Retention of three fissure sealants and a dentin bonding system used as fissure sealant in caries prevention: 12-month follow-up results.

Med Oral Patol Oral Cir Bucal. 2007 Oct;12(6):E459-63

Authors: Baca P, Bravo M, Baca AP, Jiménez A, González-Rodríguez MP

BACKGROUND: Bonding agents could be used as fissure sealants. This study compares the retention three fissure sealants (Delton, Delton Plus and Concise) and a filled dentin bonding system (Optibond Solo). METHODS. Fifty-six children aged 7-8 years received fissure sealants either in the four permanent first molars, in the four deciduous second molars, or in all eight of these teeth. Every child received a different sealing material in each quadrant on a random basis. Clinical evaluation at 12 months was performed by a single blind examiner, and the retention was classified as either a success (total retention) or a failure (partial retention or not present). RESULTS: There were no statistically significant differences among the four materials in permanent maxillary molars or deciduous molars. In permanent mandibular molars, Optibond Solo showed a lower percentage of retention (40.9%), significantly different (p=0.002) to that of Delton (89.5%), Delton Plus (87.5%) and Concise (76.5%). CONCLUSION: One bottle dentin bonding system used as a sealant does not improve the retention of conventional fissure sealants. CLINICAL IMPLICATION: Because of the scarcity of studies on the use of dental adhesives as sealants, further studies are warranted for the final support of that conclusion.

PMID: 17909514 [PubMed - indexed for MEDLINE]

Dental trauma: restorative procedures using composite resin and mouthguards for prevention.

J Contemp Dent Pract. 2007;8(6):89-95

Authors: Santos Filho PC, Quagliatto PS, Simamoto PC, Soares CJ

AIM: The aim of this article is to describe a step-by-step protocol for emergency care of a patient with a dentoalveolar injury in the anterior region of the mouth as well as the fabrication of a mouthguard to prevent future trauma. BACKGROUND: Dental trauma is one of the most serious oral health problems in active children and adolescents. Care of traumatized patients requires immediate initial emergency treatment followed by integrated procedures to restore damaged oral structures along with a subsequent trauma prevention strategy. Dentoalveolar injuries in the anterior region of the mouth are often characterized by tooth avulsion and coronal fracture. They are managed using procedures such as dental splinting, endodontic therapy with its unique characteristics, and restorative techniques to re-establish function and esthetics as well as protective mouthguards. REPORT: A 16-year-old male presented with avulsion of his maxillary central incisors as a result of a direct, unintentional impact with an opponent during a basketball game. The teeth had been stored in physiological serum immediately following the injury and the patient received immediate care. On clinical examination, the right central incisor was fractured at the incisal third of the crown but no bone fractures were found. The teeth were reimplanted and splinted. The fractured right central incisor was restored following endodontic treatment and a mouthguard was fabricated for the patient. SUMMARY: The dentist must be knowledgeable about the most efficient and suitable treatment for each traumatic scenario in order to provide appropriate care for dental injuries. Coordinated multi-disciplinary action is fundamental in the successful treatment of these injuries. The dental mouthguard is an effective device for protecting the teeth and supportive structures during physical activities and must be part of the protective equipment used by athletes. It is the responsibility of the dental professional to make parents, trainers, and athletic associations aware of the risks associated with physical activities without orofacial protection; this should encourage the proper use of all protective devices to prevent dentoalveolar injuries that compromise oral functions, esthetics, and increase the cost of healthcare.

PMID: 17846676 [PubMed - indexed for MEDLINE]

Bond strength of composite resin luting cements to fiber-reinforced composite root canal posts.

J Contemp Dent Pract. 2007;8(6):17-24

Authors: Le Bell-Rönnlöf AM, Lahdenperä M, Lassila LV, Vallittu PK

AIMS: The aim of this study was to compare the attachment of different composite resin luting cements to a fiber-reinforced composite (FRC) post with a semi-interpenetrating polymer network polymer matrix. METHODS AND MATERIALS: Six different brands of composite resin luting cement stubs were applied on the surface of FRC post material and light-cured for 40 seconds. Shear bond strengths of luting cement stubs were measured using a universal testing machine. RESULTS: The differences in shear bond strengths between the cements were not statistically significant. CONCLUSION: All of the tested composite resin luting cements provided acceptable attachment to the tested FRC post. The tested FRC post material is suitable to use with different composite resin luting cements.

PMID: 17846667 [PubMed - indexed for MEDLINE]

The influence of temperature on the efficacy of polymerization of composite resin.

J Contemp Dent Pract. 2007;8(6):9-16

Authors: Awliya WY

AIM: The purpose of this study was to investigate the effect of different temperatures on the efficacy of polymerization during the insertion of composite resin using different light curing units. METHODS AND MATERIALS: A total of 45 disc-shaped specimens were fabricated from Z250 composite resin (3M/ESPE, St. Paul, MN, USA) with 15 each prepared at three different temperatures (refrigerated to 5 masculineC, room temperature at 25 masculineC, and preheated to 37 masculineC). Each of these temperature-controlled specimen groups of 15 were then subdivided into three groups of five specimens, according to the type of curing light used to polymerize them. Curing lights included a conventional halogen light (QTH) in two modes (continuous and soft-start polymerization) and a light emitting diode (LED). The microhardness of the top and bottom surfaces of the specimens was determined using a Buehler Micromet II digital microhardness tester (Buehler, Dusseldorf, Germany). Data obtained was analyzed using two-way analysis of variance (ANOVA)/Post Hoc Tukey's test at a 0.05 significance level. RESULTS: As the temperature of composite resin increased, the top and bottom microhardness of the specimens also increased regardless of the type of polymerizing light used. The LED light produced a significantly better hardness on top and bottom surfaces of composite resin specimens polymerized at the three different temperatures. Effectiveness of cure at top and bottom surfaces of composite specimens was significantly reduced by using soft-start curing. CONCLUSION: The use of pre-warmed composite resins might help to improve polymerization of composite resin especially at the deeper areas of a restoration which could result in an increase in the expected life of a composite restoration.

PMID: 17846666 [PubMed - indexed for MEDLINE]

Effect of light curing modes and light curing time on the microhardness of a hybrid composite resin.

J Contemp Dent Pract. 2007;8(6):1-8

Authors: Aguiar FH, Braceiro A, Lima DA, Ambrosano GM, Lovadino JR

AIMS: The aim of this in vitro study was to evaluate the influence of light curing modes and curing time on the microhardness of a hybrid composite resin. METHODS AND MATERIALS: Forty-five Z250 composite resin specimens (3M-ESPE Dental Products, St. Paul, MN, USA) were randomly divided into nine groups (n=5): three polymerization modes (conventional-550 mW/cm2; light-emitting diodes (LED)-360 mW/cm2, and high intensity-1160 mW/cm2) and three light curing times (once, twice, and three times the manufacturer's recommendations). All samples were polymerized with the light tip 8 mm from the specimen. Knoop microhardness measurements were obtained on the top and bottom surfaces of the sample. RESULTS: Conventional and LED polymerization modes resulted in higher hardness means and were statistically different from the high intensity mode in almost all experimental conditions. Tripling manufacturers' recommended light curing times resulted in higher hardness means; this was statistically different from the other times for all polymerization modes in the bottom surface of specimens. This was also true of the top surface of specimens cured using the high intensity mode but not of conventional and LED modes using any of the chosen curing times. Top surfaces showed higher hardness than bottom surfaces. CONCLUSIONS: It is important to increase the light curing time and use appropriate light curing devices to polymerize resin composite in deep cavities to maximize the hardness of hybrid composite resins.

PMID: 17846665 [PubMed - indexed for MEDLINE]

Analysis of the relationship between the surface hardness and wear resistance of indirect composites used as veneer materials.

Braz Dent J. 2007;18(1):60-4

Authors: Faria AC, Benassi UM, Rodrigues RC, Ribeiro RF, Mattos Mda G

This study evaluated the surface hardness and wear resistance of indirect composites (Artglass and Solidex) and the existence of a correlation between these properties. Twenty-four specimens (12 per material) were fabricated using a polytetrafluoroethylene matrix (5.0 mm in diameter; 7.0 mm high) following an incremental technique. Polymerization was done with a xenon stroboscopic light curing unit. After polishing, the specimens were stored in water at 37 degrees C during either 1 day (n=6 per material) or 55 days (n=6 per material), after which Vickers surface hardness and wear resistance were assessed. Data were analyzed statistically by unpaired Student t-test, two-way ANOVA and Tukey's test. SURFACE HARDNESS: Artglass had higher surface hardness than Solidex after 1-day immersion period (p<0.01), but after 55 days there was no significant difference between the materials (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p<0.01), while no significant difference was found between Solidex means (p>0.05). WEAR RESISTANCE: Solidex had higher wear than Artglass after 1-day immersion period (p<0.01), but no significant difference was found between the materials after 55 days (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p<0.01), with higher wear at 55-day period, but no difference was found between Solidex means (p>0.05). These results suggest that Artglass was better than Solidex in terms of hardness and wear resistance after 1-day water immersion. However, it was more susceptible to degradation, showing greater wear after 55 days. In conclusion, there was an inverse correlation between surface hardness and wear resistance for both Artglass and Solidex indirect composites, that is the higher the hardness, the lower the wear.

PMID: 17639203 [PubMed - indexed for MEDLINE]

Effect of air abrasion on tensile bond strength of a single-bottle adhesive/indirect composite system to enamel.

Braz Dent J. 2007;18(1):45-8

Authors: Silva PC, Gon&#xE7;alves M, Nascimento TN, Centola AL

This study evaluated the efficiency of air abrasion alone and associated with phosphoric acid etching on tensile bond strength of a single-bottle adhesive/indirect composite restorative system (Bond 1/Alert) to human enamel. Forty enamel surfaces from extracted human third molars were assigned to 4 groups (n= 10). Mach 4.1 (Kreativ Inc.) air abrasion equipment was used for 20 s. A special system of rod pairs aligned in a specific apparatus was used for tensile strength tests, according to ISO/TR 11405 standard (1994) with some modifications. Bond strength means were: G1 (air abrasion + rinsing + condensable composite resin Alert) = 3.46 +/- 0.83 MPa; G2 (air abrasion + rinsing + Bond 1 adhesive system + Alert) = 4.00 +/- 1.60 MPa; G3 (air abrasion + rinsing + 37% phosphoric acid + rinsing + Bond 1 + Alert) = 20.80 +/- 3.95 MPa; and G4 (37% phosphoric acid + rinsing + Bond 1 + Alert) = 17.00 +/- 2.74 MPa. The statistical analysis by Kruskal-Wallis test revealed that G1 and G2 presented statistically significant difference (p< 0.05) from G3 and G4 (p<0.01) and G1 and G3 did not differ significantly (p> 0.05) from G2 and G4, respectively.

PMID: 17639200 [PubMed - indexed for MEDLINE]

Dentin bond strength of composites with self-etching adhesives using LED curing lights.

J Contemp Dent Pract. 2007;8(5):34-42

Authors: Korkmaz Y, Attar N

AIM: The purpose of this study was to investigate the effect of light-emitting diode (LED) light curing units (LCUs) compared with halogen LCUs on the shear bond strength (SBS) of one nanofill composite (Filtek Supreme) and one microhibrid composite (Artemis) with self-etch adhesives. METHODS AND MATERIALS: The buccal surfaces of 60 non-carious extracted human molars were flattened to expose dentin and, subsequently, polished for 60 seconds with 600-grit wet silicon carbide abrasive paper. Specimens were assigned into six groups (n=10) according to composite material, self-etch adhesive, and curing light used as follows: Group 1: Adper Prompt L-Pop (AP) and Filtek Supreme (FS) using an Elipar Free Light (EFL); Group 2: AP and FS using an Elipar Free Light 2 (EFL2); Group 3: AP and FS using a Hilux Expert (HE) light, Group 4: AdheSE (AS)+Artemis (AR) using an EFL; Group 5: AS+AR using an EFL2; and Group 6: AS+AR using a HE light. The specimens were thermocycled for 500 cycles (5 masculineC-55 masculineC) and then loaded to failure in a Zwick universal testing machine at a crosshead speed of 5 mm/minute. SBS values were calculated as megapascals (MPa) and statistically analyzed using the one-way analysis of variance (ANOVA) test at a significance level of 0.05. RESULTS: Mean SBS (+/- standard deviations) values were as follows: Group1: 15.99+/-5.18; Group 2: 18.76+/-6.71; Group 3: 17.70+/-5.04; Group 4: 16.93+/-3.99; Group 5: 18.01+/-5.19, and Group 6: 17.46+/-5.40. There were no statistically significant differences for SBS to dentin among the groups tested. CONCLUSION: The LED curing lights used in the study seem to be comparable with the halogen curing light for nanofill and microhybrid composites used in conjunction with self-etching systems in dentin. The EFL2 reduces curing time, which can be considered as an advantage.

PMID: 17618328 [PubMed - indexed for MEDLINE]

Chlorhexidine's effect on sealing ability of composite restorations following Er:YAG laser cavity preparation.

J Contemp Dent Pract. 2007;8(5):26-33

Authors: Geraldo-Martins VR, Robles FR, Matos AB

AIM: The aim of this study was to evaluate the influence of chlorhexidine on microleakage of composite restorations in class V cavities prepared with a carbide bur (CB) and a erbium:yttrium-aluminum-garnet (Er:YAG) laser. METHODS AND MATERIALS: Cavity preparations were created on the buccal surfaces of 48 bovine incisors using different methods then equally dividing them into four groups. Groups I and II were prepared with a #56 CB in a high speed handpiece while Groups III and IV were prepared with a Er:YAG laser at 350m J/4Hz on enamel and at 80.24 J/cm2 on dentin. The cavity preparations were rinsed with 2% chlorhexidine solution before the application of Clearfill SE Bond system and placement of a Z100 composite resin restoration. After 24 hours, the teeth were polished, thermocycled, and sealed with cosmetic varnish. The samples were then immersed in 2% methylene blue for four hours and sectioned in the buccolingual direction to determine the degree of microleakage. RESULTS: After statistical analysis (Kruskal-Wallis, p<0.05), no significant differences were verified among the tested groups and between the evaluated cervical or incisal margins of the restoration. CONCLUSION: The use of the chlorhexidine did not interfere with the adhesion process regardless of whether a CB or the Er:YAG laser were used to prepare class V cavities when restored with the tested self-etching adhesive system.

PMID: 17618327 [PubMed - indexed for MEDLINE]

Surface roughness and adherence of Candida albicans on soft lining materials as influenced by accelerated aging.

J Contemp Dent Pract. 2007;8(5):18-25

Authors: Tari BF, Nalbant D, Dogruman Al F, Kustimur S

AIM: Candida albicans (C. albicans) has been widely associated with the etiology of denture-related stomatitis and has been found on soft denture lining materials. The aim of this study was to examine the surface roughness and adherence of C. albicans to saliva coated and non-coated soft lining materials by subjecting them to an in vitro accelerated aging test. METHODS AND MATERIALS: Samples were prepared from three soft lining materials (Visco Gel, Ufi Gel P, Molloplast B). Surface roughness measurements and adhesion of C. albicans were examined before and after an aging process. The stimulated human whole saliva was used to assess its effect on adhesion. RESULTS: The aging process promotes the surface roughness of soft lining materials. The aging surface roughness of Visco Gel was significantly higher than Ufi Gel P and Molloplast B. No significant difference was observed between non-aged and uncoated materials, but aged and uncoated soft lining materials showed a greater adherence of C. albicans. No significant difference was observed between non-aged and saliva coated materials, but aged and saliva coated soft lining materials showed a greater adherence of C. albicans. CONCLUSIONS: Candidosis induced by C. albicans is the most common fungal infection. Awareness of susceptibility of soft lining materials to the adherence of C. albicans is an important factor in their selection. The use of soft lining materials with smooth surfaces minimizes the adherence of C. albicans.

PMID: 17618326 [PubMed - indexed for MEDLINE]

Three-dimensional surface profile analysis of different types of flowable restorative resins following different finishing protocols.

J Contemp Dent Pract. 2007;8(5):9-17

Authors: Yazici AR, M&#xFC;ftü A, Kugel G

AIM: The aim of this study was to investigate the surface roughness of different types of flowable restorative resins and compare the effectiveness of diamond finishing burs followed by aluminum oxide discs with aluminum oxide discs alone in producing smooth surfaces. METHODS AND MATERIALS: Twenty-four specimens (10 mm X 2 mm) for each flowable resin (flowable microhybrid composite, flowable liquid microhybrid composite, flowable compomer, and flowable ormocer) were fabricated in an acrylic mold and randomly assigned to three groups. In group I samples were left undisturbed after the removal of a Mylar strip (control). In group II samples were polished with diamond finishing burs, followed by aluminum oxide discs. In group III samples were finished with only aluminum oxide discs. The mean surface roughness (Ra, microm) was determined with 3-D non-contact interferometry. Data were subjected to one way analysis of variance (ANOVA), and post hoc comparison was accomplished using Tukey's HSD. RESULTS: Although significant differences in surface roughness (Ra) values were observed among the materials using a Mylar strip (control), no significant differences between restorative materials were found when all finishing/polishing methods were combined. For all flowable restorative resins tested, the Mylar strip produced surfaces smoother than those produced by a diamond finishing bur followed by a disc or by using discs alone. Surface roughness values were statistically similar for a diamond finishing bur followed by a disc and for disc treated surfaces within each material except for Dyract Flow, a flowable compomer. CONCLUSION: Although the surface roughness of flowable restorative resins differs among the types, this difference can be overcome with different finishing/polishing methods.

PMID: 17618325 [PubMed - indexed for MEDLINE]

[Antifungal activity of the novel adduct, GX-95, of silver with nanometer-scale particles to peptidic hydrolysates from collagen]

Nippon Ishinkin Gakkai Zasshi. 2007;48(2):97-100

Authors: Yaguchi T, Takizawa K, Taguchi H, Tanaka R, Kubota T, Kubota Y, Kubota M, Fukushima K

Silver has long been known to have an antimicrobial activity against bacteria and other microorganisms, and has been used as eating utensils, as dental fillings and so on. We developed a novel adduct, GX-95, of silver with nanometer-scale particles to peptidic hydrolysates from collagen. Antifungal activity of the adduct against pathogenic yeasts and filamentous fungi was examined in terms of minimal inhibitory concentrations (MICs). GX-95 was found to possess strong and broad antifungal activities against all fungi examined in the following MICs: 0.25 to 0.31 microg/ml for Candida albicans including resistant strains to fluconazole, itraconazole and flucytosine, 0.05 to 0.2 microg/ml for Cryptococcus neoformans strains, 0.025 to 0.4 microg/ml for Aspergillus fumigatus strains, 0.4 microg/ml for Trichophyton rubrum, and 0.05 microg/ml for Cladophialophora carrionii.

PMID: 17502845 [PubMed - indexed for MEDLINE]

Comparative evaluation of the marginal sealing ability of Fuji VII and Concise as pit and fissure sealants.

J Contemp Dent Pract. 2007;8(4):10-8

Authors: Ganesh M, Shobha T

AIM: The anatomical pits and fissures of the teeth have long been recognized as susceptible areas for the initiation of dental caries. The extreme vulnerability to decay of these pits and fissures on the occlusal surfaces has prompted dental scientists to seek methods of caries prevention. Motivated by the role of pit and fissure sealants in caries prevention, the aim of this study was to compare the efficacy of Fuji VII glass ionomer sealant and Concise resin-based sealant. METHODS AND MATERIALS: An in vitro study was undertaken using forty premolars extracted for orthodontic reasons. The teeth were divided into two groups and sealants were applied. One was an experimental group using Fuji VII as a pit and fissure sealant and the other a control group using Concise. The teeth were kept in gentian violet dye for 24 hours, the sectioned samples were observed for the extent of dye penetration, and scores were based on established scoring criteria. RESULTS: The comparison of the performance of the two groups showed a statistically significant difference. CONCLUSION: The Concise resin-based sealant performed better in terms of sealing ability than did the Fuji VII glass ionomer sealant.

PMID: 17486182 [PubMed - indexed for MEDLINE]

Analysis of the diametral compressive bond strength between composite resin and amalgam in different stages of oxidation.

Minerva Stomatol. 2007 Apr;56(4):209-13

Authors: Benitez Catirse AB, Oliveira Pagnano V, Da Silva Mello AS, Do Nascimento C, Mardegan Issa JP

AIM: Amalcomp is a technique that combines composite resin to amalgam in restorative procedures to improve esthetics and minimize the negative effects of polymerization on dental tissues. The objective of this in vitro study was to measure the diametral compressive bond strength between Fill Magic composite (Vigodent) versus Permite (DFL) or Velvalloy (SS White) amalgams in different oxidation stages. METHODS: Twenty-four cylinders of each amalgam brand were fabricated using a Teflon matrix and divided into 3 groups according to the immersion period in artificial saliva for oxidation: A (1 day), B (7 days) and C (30 days). After immersion, the amalgam cylinders were bonded to the composite specimens using the Scotch Bond Multi Use Plus (3M) bonding system. Diametral compression assays were then carried out in an EMIC-MEM 2000 universal testing machine set to 0.5 mm/min. Statistical analysis was performed using ANOVA and Tukey's test. RESULTS: The mean recorded strength (MPa) for each oxidation group was: A=9.71, B=8.21 and C=6.98 (A>B = C; P<0.01). Permite (7.24) provided significantly less adhesion to the composite than Velvalloy (9.36; P<0.05). There was no interaction between the factors alloy, resin and time. CONCLUSIONS: Under the conditions of this study, the less oxidized amalgam showed the greatest diametral compressive strength values.

PMID: 17452958 [PubMed - indexed for MEDLINE]

Biomolecular surface coating to enhance orthopaedic tissue healing and integration.

Biomaterials. 2007 Jul;28(21):3228-35

Authors: Reyes CD, Petrie TA, Burns KL, Schwartz Z, Garc&#xED;a AJ

Implant osseointegration is a prerequisite for clinical success in orthopaedic and dental applications, many of which are restricted by loosening. Biomaterial surface modification approaches, including calcium-phosphate ceramic coatings and macro/microporosity, have had limited success in promoting integration. To improve osseointegration, titanium surfaces were coated with the glycine-phenylalanine-hydroxyproline-glycine-glutamate-arginine (GFOGER) collagen-mimetic peptide, selectively promoting alpha2beta1 integrin binding, a crucial event for osteoblastic differentiation. Titanium surfaces presenting GFOGER triggered osteoblastic differentiation and mineral deposition in bone marrow stromal cells, leading to enhanced osteoblastic function compared to unmodified titanium. Furthermore, this integrin-targeted coating significantly improved in vivo peri-implant bone regeneration and osseointegration, as characterized by bone-implant contact and mechanical fixation, compared to untreated titanium in a rat cortical bone-implant model. GFOGER-modified implants also significantly enhanced osseointegration compared to surfaces modified with full-length type I collagen, highlighting the importance of presenting specific biofunctional domains within the native ligand. In addition, this biomimetic implant coating is generated using a simple, single-step procedure that readily translates to a clinical environment with minimal processing and cytotoxicity concerns. Therefore, this study establishes a biologically active and clinically relevant implant-coating strategy that enhances bone repair and orthopaedic implant integration.

PMID: 17448533 [PubMed - indexed for MEDLINE]

Development of a peptide-containing chewing gum as a sustained release antiplaque antimicrobial delivery system.

AAPS PharmSciTech. 2007;8(1):26

Authors: Faraj JA, Dorati R, Schoubben A, Worthen D, Selmin F, Capan Y, Leung K, DeLuca PP

The objective of this study was to characterize the stability of KSL-W, an antimicrobial decapeptide shown to inhibit the growth of oral bacterial strains associated with caries development and plaque formation, and its potential as an antiplaque agent in a chewing gum formulation. KSL-W formulations with or without the commercial antibacterial agent cetylpyridinium chloride (CPC) were prepared. The release of KSL-W from the gums was assessed in vitro using a chewing gum apparatus and in vivo by a chew-out method. A reverse-phase high-performance liquid chromatography method was developed for assaying KSL-W. Raw material stability and temperature and pH effects on the stability of KSL-W solutions and interactions of KSL-W with tooth-like material, hydroxyapatite discs, were investigated. KSL-W was most stable in acidic aqueous solutions and underwent rapid hydrolysis in base. It was stable to enzymatic degradation in human saliva for 1 hour but was degraded by pancreatic serine proteases. KSL-W readily adsorbed to hydroxyapatite, suggesting that it will also adsorb to the teeth when delivered to the oral cavity. The inclusion of CPC caused a large increase in the rate and extent of KSL-W released from the gums. The gum formulations displayed promising in vitro/in vivo release profiles, wherein as much as 90% of the KSL-W was released in a sustained manner within 30 minutes in vivo. These results suggest that KSL-W possesses the stability, adsorption, and release characteristics necessary for local delivery to the oral cavity in a chewing gum formulation, thereby serving as a novel antiplaque agent.

PMID: 17408225 [PubMed - indexed for MEDLINE]

A rational use of dental materials in posterior direct resin restorations in order to control polymerization shrinkage stress.

Minerva Stomatol. 2007 Mar;56(3):129-38

Authors: Giachetti L, Bertini F, Bambi C, Scaminaci Russo D

One of the main problems when using resin-based composites is the resulting polymerization shrinkage stress. Composite strain is hindered every time the composite is bonded to the tooth's walls. In the pre-gel phase the shrinkage stress is reduced by the composite flow from the free to the bonded surface areas. Therefore, no stress develops at the dentine-composite interface. When a gel point is reached, the composite flow no longer compensates for the volumetric shrinkage. The generated stress may cause adhesive failure and several other adverse clinical consequences such as enamel fracture, cracked cusps, cuspal movement, microcracking of the restorative material and gaps between the resin and cavity walls which may cause secondary caries and postoperative sensitivity. A sensible use of materials in direct restorations may contribute to a reduced rate of shrinkage stress. To this aim glass-ionomer cement as well as flowable, light-curing and self-curing composites were examined. The aim of this study was to provide some useful information for a sensible choice of restoration materials in order to control shrinkage stress and its negative consequences in direct posterior restorations.

PMID: 17327817 [PubMed - indexed for MEDLINE]

Effect of two microwave disinfection protocols on adaptation of poly (methyl methacrylate) denture bases.

Minerva Stomatol. 2007 Mar;56(3):121-7

Authors: Fleck G, Ferneda F, Ferreira da Silva DF, Mota EG, Shinkai RS

AIM: A few protocols of microwave irradiation have been proposed for disinfection of dental prostheses, but their effect on dimensional alteration still is unknown. This study evaluated the effect of 2 protocols of microwave disinfection on adaptation of resin denture bases polymerised by conventional hot water bath or by microwave energy. METHODS: Thirty-six resin bases were obtained from stone casts duplicated from a metallic master model of an edentulous maxilla and polymerised by either conventional hot water bath or microwave energy. Experimental disinfection treatments were: 1) control (no disinfection); 2) protocol 1 (690 W/6 min); 3) protocol 2 (345 W/6 min). Disinfection procedures were performed 3 times (T1, T2, T3) with a 7-day interval. Adaptation was measured by weighing a vinyl polysiloxane film reproducing the gap between resin base and master model. Data were analysed by ANOVA for repeated measures and Bonferroni test (a=0.05). RESULTS: In T1 and T2, all groups polymerised by microwave energy had higher mean values than the groups polymerised by conventional technique. In T3, denture resin bases polymerised by microwave energy had increased poor adaptation when submitted to microwave disinfection at 690 W for 6 min. No significant changes were found for bases submitted to microwave disinfection at 345 W for 6 min (P>0.05). CONCLUSIONS: Adaptation of denture bases varied as a function of polymerisation technique and protocol of microwave disinfection (power and time) over time. Microwave disinfection at 690 W for 6 min proved harmful to denture bases after repeated disinfection procedures.

PMID: 17327816 [PubMed - indexed for MEDLINE]

Apical seal comparison of low-temperature thermoplasticized gutta-percha technique and lateral condensation with two different master cones.

Med Oral Patol Oral Cir Bucal. 2007 Mar;12(2):E175-9

Authors: P&#xE9;rez Heredia M, Clavero González J, Ferrer Luque CM, González Rodríguez MP

AIM: To compare the apical sealing in mesio-buccal canals of extracted molars obturated with low-temperature thermoplasticized gutta-percha or cold lateral condensation techniques using a .06 or a .02 mm/mm tapered gutta-percha master cone. The secondary aim was to evaluate the depth of spreader penetration in root canals using a .06 or a .02 mm/mm tapered gutta-percha master cone. METHODOLOGY: Forty-four mesio-buccal curved canals (25-40 degree) were instrumented with .06 nickel-titanium rotary instruments and randomly distributed into two control groups (n=4) and three experimental groups (n=12) for obturation by the Ultrafil 3D system or by cold lateral condensation with .06 or .02 tapered master cone. Canal sealer AH-Plus was used. The depth of spreader penetration was recorded in millimetres. Roots were covered with two layers of nail polish, immersed in India ink for 7 days, transversally sectioned and examined with a stereomicroscope. Student s t test was used to determine whether there was a difference in spreader penetration between groups. Kruskal-Wallis test was used to determine whether there was a difference in leakage. RESULTS: There were no differences among the three groups (p=0.396), which showed a very similar mean microleakage (0.42, 0.75 and 0.42). The difference in spreader penetration between the groups filled by cold lateral condensation was significant (p=0.001) CONCLUSION: The Ultrafil 3D system and cold lateral condensation techniques with .06 or .02 tapered master cones were equally effective in the apical sealing of curved canals. The spreader penetrated deeper using a .02 mm/mm tapered gutta-percha master cone.

PMID: 17322810 [PubMed - indexed for MEDLINE]

Augmentation of keratinized gingiva through bilaminar connective tissue grafts: a comparison between two techniques.

Minerva Stomatol. 2007 Jan-Feb;56(1-2):3-20

Authors: Bertoldi C, Bencivenni D, Lucchi A, Consolo U

AIM: A mucogingival deficiency is considered a potential risk factor for periodontal disease. In particular, mucogingival deficiency can lead to gingival recession, which is a pathological entity per se, due to the increased risk for dental hypersensitivity and root caries. The aim of this study was to evaluate and compare 2 bilaminar grafting techniques normally employed to achieve root coverage. METHODS: Thirty-five patients were divided into 2 groups. Group 1 included 19 patients with 49 gingival recessions treated by Nelson technique (as modified by Harris), while group 2 included 15 patients with 40 recessions treated by Langer technique. Clinical evaluation was performed at preoperative level (T0), after 1 month (T1) and after 1 year (T2). Statistical analysis was performed by means of Friedmann and Wilcoxon test and U-Mann-Whitney test. RESULTS: The statistical analysis did not reveal any significant difference between groups, both in terms of percentage of root coverage and of width of keratinizaed gingiva gain. A significant difference was only observed within each group, for the amount of keratinized gingiva at T1 vs T0 and at T2 vs T1. CONCLUSIONS: This study did not show any statistical difference between the Nelson and the Langer technique as to root coverage and gain in keratinized gingiva.

PMID: 17287702 [PubMed - indexed for MEDLINE]

Split-increment technique: an alternative approach for large cervical composite resin restorations.

J Contemp Dent Pract. 2007;8(2):121-8

Authors: Hassan KA, Khier SE

AIM: This article proposes and describes the split-increment technique as an alternative for placement of composite resin in large cervical carious lesions which extend onto the root surface. TECHNIQUE: Two flat 1.5 mm thick composite resin increments were used to restore these cervical carious lesions. Prior to light-curing, two diagonal cuts were made in each increment in order to split it into four triangular-shaped flat portions. The first increment was applied to cover the entire axial wall and portions of the four surrounding walls. The second increment was applied to fill the cavity completely covering the first one and the rest of the four surrounding walls as well as sealing all cavity margins. CLINICAL SIGNIFICANCE: This technique results in the reduction of the C-factor and the generated shrinkage stresses by directing the shrinking composite resin during curing towards the free, unbonded areas created by the two diagonal cuts. The proposed technique would also produce a more naturally looking restoration by inserting flat dentin and enamel increments of composite resin of a uniform thickness which closely resembles the arrangement of natural tooth structure.

PMID: 17277835 [PubMed - indexed for MEDLINE]

Effect of centripetal and incremental methods in Class II composite resin restorations on gingival microleakage.

J Contemp Dent Pract. 2007;8(2):113-20

Authors: Ghavamnasiri M, Moosavi H, Tahvildarnejad N

AIM: The aim of this study was to evaluate the microleakage at gingival margins below the cementoenamel junction (CEJ) of Class II composite restorations using various placement techniques. METHODS AND MATERIALS: Sound human maxillary premolars were selected. Eighty slot-style cavities on the mesial or distal surfaces were prepared with the cervical margins located apical to the CEJ. The specimens were divided into two groups based on the restorative technique utilized (centripetal or incremental). Each group was then categorized into two subgroups according to the type of matrix used resulting in a total of four experimental groups as follows: IP=Incremental and Palodent matrix, IT = Incremental and Transparent matrix, CP= Centripetal and Palodent matrix, and CT = Centripetal and Transparent matrix. Following restoration with a total etch adhesive (Single Bond) and a resin composite (Z100), the teeth were thermocycled. Then specimens were immersed in 0.5% basic fuchsin dye for 24 hours at a temperature of 37 degrees C. Sectioned restorations were examined under a stereomicroscope (40X magnification), and the extent of the microleakage was scored and recorded. Data were analyzed using the Kruskal-Wallis non-parametric statistical test (P=0.05). RESULTS: In the four groups of the study no significant differences in the mean rank of microleakage were observed (p>0.05). CONCLUSION: When the gingival margin was located on cementum, the kind of matrix and filling technique did not reduce the microleakage.

PMID: 17277834 [PubMed - indexed for MEDLINE]

A comparison of two different methods and materials used to repair polycarbonate crowns.

J Contemp Dent Pract. 2007;8(2):105-12

Authors: Yilmaz A

AIM: The aim of this study was to evaluate the bond strength and crown-repair material interface of polycarbonate crown repaired using flowable resin composite and hybrid resin composite following two different surface preparations. METHODS AND MATERIALS: The facial surfaces of fifty-two polycarbonate crowns were flattened and roughened. Specimens were then divided into four test groups. A bonding agent alone (Groups 1 and 2) or a combination of methylmethacrylate (MMA) + bonding agent (Groups 3 and 4) was applied to the prepared surfaces. Then either a flowable (Groups 1 and 3) or a microfilled hybrid (Groups 2 and 4) resin composite was placed on the surfaces. Forty-eight of the original fifty-two specimens were used for shear bond strength testing. Failure types (adhesive, cohesive, and mixed) were evaluated. The remaining four specimens, one from each group, were used for crown-resin composite interface analysis using a scanning electron microscope (SEM). RESULTS: There were significant differences in both mean shear bond strength values and failure types (P<0.05). The SEM evaluation revealed a close interface relationship in Groups 3 and 4. CONCLUSION: MMA monomer application on a polycarbonate crown prior to application of an adhesive agent improved the shear bond strength of the repair material.

PMID: 17277833 [PubMed - indexed for MEDLINE]

The effect of different finishing and polishing systems on the surface roughness of different composite restorative materials.

J Contemp Dent Pract. 2007;8(2):89-96

Authors: U&#xE7;taşli MB, Arisu HD, Omürlü H, Eligüzeloğlu E, Ozcan S, Ergun G

AIM: The purpose of this in vitro study was to examine the effect of two different finishing systems on the surface roughness of different types of composite restorative materials. METHODS AND MATERIALS: Thirty specimens, 8 mm in diameter and 3 mm in depth, were prepared using a microfill composite (Clearfil ST, Kuraray Co. Ltd., Osaka, Japan), a hybrid composite (Clearfil AP-X, Kuraray Co. Ltd., Osaka, Japan), and a packable composite (Clearfil Photo Posterior, Kuraray Co. Ltd., Osaka, Japan) cured against a Mylar matrix strip to create a baseline surface. The average surface roughness was measured using a surface profilometer (Surftest 211, Mitutoyo, Japan) in five different positions on each sample before and after finishing with one of the two finishing systems [Sof-Lex discs (3M) and Po-Go (Dentsply)]. The obtained data were analyzed by two-way analysis of variance (ANOVA) at a p=0.05 significance level. RESULTS: There were statistically significant differences in the average surface roughness (Ra, microm) between the Mylar matrix strip, Sof-Lex discs, and Po-Go discs (p<0.05). For all tested materials, the Mylar matrix strip provided smoother surfaces than both of the finishing systems (p<0.05). When the finishing discs were compared, Sof-Lex discs produced a smoother surface than Po-Go discs for all tested materials (p<0.05). CONCLUSION: The Mylar matrix strip provided a smoother surface than Sof-Lex and Po-Go discs. Furthermore, Sof-Lex discs produced smoother surfaces than Po-Go discs. Sof-Lex and Po-Go systems produced clinically acceptable surface roughness for microfill, hybrid, and packable composite resin materials. The effect of finishing and polishing systems on surface roughness was dependent on both the system and the composite resin restorative material.

PMID: 17277831 [PubMed - indexed for MEDLINE]

Effect of two light-emitting diode (LED) and one halogen curing light on the microleakage of Class V flowable composite restorations.

J Contemp Dent Pract. 2007;8(2):80-8

Authors: Attar N, Korkmaz Y

AIM: The disadvantages of light cured composite resin materials with respect to microleakage are predominantly a result of polymerization shrinkage upon curing. It has been shown curing methods play a significant role in polymerization shrinkage of light-cured composite resins. The purpose of this study was to investigate the effect of light-emitting diode (LED) light curing units (LCUs) compared with a halogen LCU on microleakage of three different flowable composites using self-etch adhesives. METHODS AND MATERIALS: A total of 63 extracted human premolars were prepared with standardized Class V cavity preparations on the buccal and lingual surfaces of each tooth. The occlusal margin of the cavities was located on the enamel and the gingival margin was on dentin. Teeth were randomly assigned to three groups of 21 teeth each as follows: Group 1: Adper Prompt L-Pop + Filtek Flow (3M ESPE); Group 2: AdheSE + Tetric Flow (Ivoclar, Vivadent); and Group 3: Clearfil Protect Bond + Clearfil Protect Liner F (Kuraray Medical Inc.). All the groups were subdivided into three groups according to the curing lights used (n=7). Two LED LCUs, Elipar FreeLight and Elipar FreeLight 2 (3M ESPE), and one halogen-based LCU, Hilux Expert (Benlioglu ), were used. All teeth were then immersed in 0.5% basic fuchsin dye solution for 24 hours after thermocycling (500 cycles; between 5 degrees C to 55 degrees C). The teeth then were longitudinally sectioned and observed under a stereomicroscope (40X magnification) by two examiners. The degree of dye penetration was recorded separately for enamel and dentin. Data were analyzed with the Kruskal-Wallis and Mann-Whitney tests with the Bonferroni correction. RESULTS: No statistically significant differences in microleakage were observed between groups either on enamel or dentin (p>0.05). CONCLUSION: With the limitation of this in vitro study, the differences in microleakage between LCUs used were not statistically significantly different. Elipar Free Light 2 reduces curing time which can be considered as an advantage.

PMID: 17277830 [PubMed - indexed for MEDLINE]

Effect of photoactivation systems and resin composites on the microleakage of esthetic restorations.

J Contemp Dent Pract. 2007;8(2):70-9

Authors: Cavalcante LM, Peris AR, Ambrosano GM, Ritter AV, Pimenta LA

AIM: The aim of this study was to evaluate the influence of four photoactivation systems [quartz tungsten halogen (QTH), light-emitting diode (LED), argon ion laser (AL), and plasma arc curing PAC)] on cementum/dentin and enamel microleakage of Class II restorations using a microhybrid [Z250-3M ESPE] and two packable composites [(SureFil-Dentsply and Tetric Ceram HB-Ivoclair/Vivadent]. METHODS AND MATERIALS: Three hundred sixty "vertical-slot Class II cavities" were prepared at the mesial surface of bovine incisors using a 245 carbide bur in a highspeed handpiece. Specimens were divided into twelve groups (composite-photoactivation systems). Half of the specimens had the gingival margin placed in enamel (n=15) and the other half in cementum/dentin (n=15). Composites were inserted and cured in 2 mm increments according to manufacturers' recommended exposure times. After polishing, the samples were immersed in 2% methylene blue solution, sectioned, and evaluated at the gingival margins. Data were submitted to statistical analysis using the Kruskal-Wallis and Mann-Whitney tests. RESULTS: No significant differences were found among the photoactivation systems and among resin composites (p>0.05). Microleakage was not significantly affected by location (enamel vs. cementum/dentin, p>0.05). These findings suggested neither the photoactivation systems nor the resin composite types might have an effect on the microleakage at gingival margins Class II cavities.

PMID: 17277829 [PubMed - indexed for MEDLINE]

Gap formation between different cavity walls and resin composite systems on primary and permanent teeth.

J Contemp Dent Pract. 2007;8(2):60-9

Authors: Tulunoglu O, Ulker AE

AIM: The aim of this study was to compare the effectiveness of five self-etching and etch-rinse dentin-bonding agents in achieving a gap-free adaptation between the restorative material and the dentin in primary and permanent teeth. METHODS AND MATERIALS: Gaps located at the restoration dentin interface were evaluated using scanning electron microscopy (SEM). RESULTS: There were more gaps on the corner of the cavities, but no significant difference was detected between different cavity walls (p>0,05). Statistical results of the SEM analysis revealed fewer gaps in the restorations made with self-etching dentin bonding agents than etch-rinse agents at the restoration-dentin interface in both primary and permanent teeth. CONCLUSION: Self-etching bonding systems were preferable in primary and permanent teeth according to the results of this study. However, further studies should be conducted to determine a favorable strategy to eliminate the gaps on the corners of cavities and maintain a gap-free adaptation between resin composite and tooth structure.

PMID: 17277828 [PubMed - indexed for MEDLINE]

The Knoop hardness of a composite resin polymerized with different curing lights and different modes.

J Contemp Dent Pract. 2007;8(2):52-9

Authors: Yazici AR, Kugel G, G&#xFC;l G

AIM: The purpose of this study was to compare the surface hardness of a hybrid composite resin polymerized with different curing lights. METHODS AND MATERIALS: Two 3.0 mm thick composite resin discs were polymerized in a prepared natural tooth mold using: (1) a conventional quartz-tungsten halogen light (QTH- Spectrum 800); (2) a high-intensity halogen light, Elipar Trilight (TL)-standard/exponential mode; (3) a high-intensity halogen light, Elipar Highlight (HL)-standard/soft-start mode; (4) a light-emitting diode, Elipar Freelight (LED); and (5) a plasma-arc curing light, Virtuoso (PAC). Exposure times were 40 seconds for the halogen and LED lights, and three and five seconds for the PAC light. Following polymerization, the Knoop hardness was measured at the bottom and the top surfaces of the discs. RESULTS: Significant differences were found between top and bottom Knoop Hardness number (KHN) values for all lights. The hardness of the top and bottom surfaces of both specimens cured by the PAC light was significantly lower than the other lights. No significant hardness differences were observed between the remaining curing units at the top of the 2.0 mm specimens. Significant differences were found between the LED and two modes of HL on the bottom surfaces. For the 3.0 mm thick samples, while significant differences were noted between LED and TL standard mode and between the two TL curing modes on the top, significant differences were only observed between QTH and the standard modes of TL and HL at the bottom.

PMID: 17277827 [PubMed - indexed for MEDLINE]

Radiometric and spectrophotometric analysis of third generation light-emitting diode (LED) light-curing units.

J Contemp Dent Pract. 2007;8(2):43-51

Authors: Owens BM, Rodriguez KH

AIMS: Light-emitting diode (LED) polymerization of dental restorative materials has become increasingly popular. However, individual light-curing unit (LCU) functions (intensity and/or wavelength emission) may not conform to manufacturer specifications due to quality control issues. The purpose of this study was to evaluate the quality of irradiance, in terms of power density (intensity) and spectral distribution (peak wavelength), emitted from LED and quartz-tungsten halogen (QTH) LCUs in vitro. The battery expenditure of these LED units was also tested. METHODS AND MATERIALS: The intensity and spectral distribution from four third generation LED (Smartlite PS, Coltolux LED, radii Plus, Diopower) and one QTH (Schein Visible Cure) light sources were measured using six different dental curing light meters (Coltolux, Cure Right, Demetron 100, Demetron LED., Hilux, and Light Meter-200) and a visible-ultraviolet light spectrophotometer (Hitachi Elmer-Perkins). The battery life was also plotted for each light source following a 1500 second duration period. The data obtained from radiometric and spectrophotometric analysis was compared to manufacturer specifications. RESULTS: Radiometric evaluation revealed LED light units tested did not satisfy manufacturer claims for minimum intensities. Spectral emissions from the LED light sources did meet manufacturer requirements. No clinically appreciable battery drain was evidenced from testing all re-chargeable LED units. CONCLUSION: Despite limitations LED technology appears to be an effective alternative for curing of light-activated esthetic restorative materials. Additional advantages associated with LED curing lights include ergonomic handling capabilities, negative heat generation, and minimal maintenance concerns.

PMID: 17277826 [PubMed - indexed for MEDLINE]

Effectiveness of second-generation light-emitting diode (LED) light curing units.

J Contemp Dent Pract. 2007;8(2):35-42

Authors: Campregher UB, Samuel SM, Fortes CB, Medina AD, Collares FM, Ogliari FA

AIM: The purpose of this study was to evaluate the effectiveness of three commercially available light emitting diode (LED) light curing units (LCU) (Elipar FreeLight--3M ESPE; UltraLume LED2--Ultradent; and Single V--BioArt) for polymerizing Z250-A3 composite (3M ESPE) using Knoop hardness, polymerization depth, and flexural strength properties. METHODS AND MATERIALS: The XL 2500 (3M ESPE) LCU, which is a conventional halogen unit, was used as a control. In all cases the curing time was 20 seconds. Hardness was determined 24 hours after composite cure for 10 samples of 8 mm diameter and 2 mm height for each LCU tested. Samples were stored dry in a light-proof container prior to testing. The depth of cure of the composite was measured immediately after composite polymerization for each LCU using three samples 4 mm in diameter and 6 mm in height. Flexural strength was determined for five samples 24 hours after immersion in distilled water at 37 degrees C. Each sample measured 25 mm in length, 2 mm in width, and 2 mm in height for each LCU tested. CONCLUSION: The results were treated statistically for comparison of the LCUs. In all cases the results obtained by LED LCUs were not different or were higher than a conventional halogen LCU. CLINICAL SIGNIFICANCE: Second generation LED LCUs were as effective as/or more effective than a halogen LCU for polymerization of the used composite. The present study shows second generation LEDs have the potential to replace halogen LCUs.

PMID: 17277825 [PubMed - indexed for MEDLINE]

Shear bond strength of resin modified glass ionomer cement bonded to different tooth-colored restorative materials.

J Contemp Dent Pract. 2007;8(2):25-34

Authors: Taher NM, Ateyah NZ

AIM: The aim of this study was to determine in vitro the shear bond strength (MPa) and the type of bond failure when resin-modified glass ionomer cement (RMGIC) was bonded with different tooth-colored restorative materials. METHODS AND MATERIALS: The RMGIC tested was Fuji II LC (FL) and the tooth-colored restorative materials used were composite resin Point-4 (P4), Compomer Dyract AP (DY), and Ormocere Admira (AD). A total number of 60 FL specimens were prepared using Teflon molds. The specimens were divided into six equal groups. Each group of ten specimens was bonded to a tested tooth-colored restorative material as follows: Group I--etched FL bonded to P4; Group II--non-etched FL bonded to P4; Group III--etched FL bonded to DY; Group IV--non-etched FL bonded to DY; Group V--etched FL bonded to AD; and Group VI--non-etched FL bonded to AD. The specimens were stored in distilled water at 37 degrees C for 24 hours. The shear bond strength was measured in a universal testing machine, and the fractured surfaces were examined under a stereomicroscope. RESULTS: The results of the shear bond strength indicated the lowest mean value (14.46 MPa) was in Group III, and this was significantly different from the values of other groups (p<0.05). However, Groups V and VI recorded the highest mean values (24.5 MPa and 28.39 MPa) which were significantly different (p<0.05) when compared to other groups. Groups I, II, and IV showed no significant difference with mean values of 20.06, 19.99, and 20.1 MPa which were significantly different from other groups (p<0.05). CONCLUSION: AD showed the highest shear bond strength to RMGIC. All groups demonstrated a cohesive failure in FL except for Group IV where a cohesive failure in DY was recorded. AD showed good shear bond strength when laminated with FL.

PMID: 17277824 [PubMed - indexed for MEDLINE]

The effect of thermocycling on the adhesion of self-etching adhesives on dental enamel and dentin.

J Contemp Dent Pract. 2007;8(2):17-24

Authors: El-Araby AM, Talic YF

AIM: The aim of the present study was to investigate the effectiveness of one total-etch self-priming adhesive and two one-step self-etching adhesive systems on the adhesion of a resin composite to both dentin and enamel. The effect of thermocycling on the adhesion was also investigated. The null hypothesis tested was thermocycling would not affect bond strengths to enamel and dentin treated with self-etching adhesives or a total-etch adhesive. METHODS AND MATERIALS: Two single-step self-etching adhesives [Xeno III (XE3) and Prompt L-Pop (PP)] and one two-step total-etch adhesive system (Prime & Bond NT) (P&B NT) were used in this study. Thirty caries-free unrestored human third molars were used to make specimens of enamel and dentin. Different adhesives were applied on enamel and dentin surfaces according to the manufacturer's instructions then hybrid composite restorative material was condensed on the surface using a mold. The bonded specimens were stored in distilled water at 37 masculineC for 24 hours before being tested. Half of the bonded specimens were tested for shear bond strength without thermocycling. The other half of the test specimens were thermocycled using a thermocycling apparatus in water baths held at 5 masculineC and 55 masculineC with a dwell time of one minute each for 10,000 cycles prior to shear testing. The mean shear bond strength before and after thermocycling was calculated, and the results were subjected to two-way analysis of variance (ANOVA) and repeated measure design to show the interaction between different materials and different times. RESULTS: The results showed shear bond strength on both enamel and dentin of the total-etch adhesive and the self-etching adhesives decreased after the specimens were subjected to thermocycling. CONCLUSIONS: The null hypothesis tested "thermocycling would not affect bond strengths treated with self-etching adhesives" was rejected. Furthermore, the study revealed the following: 1. The shear bond strength to both enamel and dentin of the total-etch adhesive and the self-etching adhesives decreased after the specimens were subjected to thermocycling. 2. XE3 achieved the highest bond strength to both enamel and dentin (26.994+/-1.17 and 25.22+/-1.26, respectively). 3. XE3 showed even better bonding after thermocycling to enamel and dentin than the total-etching system or PP. 4. Although PP bonded to enamel showed lower shear bond strength value than XE3, it has durable bond strength even after thermocycling.

PMID: 17277823 [PubMed - indexed for MEDLINE]

Fatigue strength of fragmented incisal edges restored with a fiber reinforced restorative material.

J Contemp Dent Pract. 2007;8(2):9-16

Authors: Garoushi SK, Lassila LV, Vallittu PK

AIM: The aim of this study was to determine the compressive fatigue limits (CFLs) of fractured incisor teeth restored using either a conventional adhesive-composite technique or using fiber-reinforced composites (FRCs). METHODS AND MATERIALS: Fifteen extracted sound upper incisor teeth were prepared by cutting away the incisal one-third part of their crowns horizontally. The teeth were restored using three techniques. Group A (control group) was restored by reattaching the original incisal edge to the tooth. Group B was restored using particulate filler composite (PFC). Group C was restored with PFC and FRC by adding a thin layer of FRC to the palatal surface of the teeth. The bonding system used was a conventional etch system with primer and adhesive. All restored teeth were stored in water at room temperature for 24 h before they were loaded under a cyclic load with a maximum controlled regimen using a universal testing machine. The test employed a staircase approach with a maximum of 103 cycles or until failure occurred. Data were analyzed using analysis of variance (ANOVA) (p=0.05). Failure modes were visually examined. RESULTS: Group A (reattaching fractured incisal edge) revealed the lowest CFL values, whereas the creation of a new incisal edge with PFC revealed a 152% higher CFL value compared to Group A. Group C (teeth restored with FRC) revealed a 352% higher CFL than the control group. ANOVA revealed the restoration technique significantly affected the compressive fatigue limit (p<0.001). The failure mode in Group A and B was debonding of the restoration from the adhesive interface. While in Group C, the sample teeth fractured below their cemento-enamel junctions. CONCLUSION: These results suggested an incisally fractured tooth restored with the combination of PFC and FRC-structure provided the highest CFL.

PMID: 17277822 [PubMed - indexed for MEDLINE]

Silane based concepts on bonding resin composite to metals.

J Contemp Dent Pract. 2007;8(2):1-8

Authors: Matinlinna JP, Vallittu PK

INTRODUCTION: The longevity of silane promoted adhesion of surface conditioned metallic materials is of concern in dentistry and poses both a functional and esthetic dilemma for the patient and dental professionals. Several methods for surface conditioning exist, but some are employed more frequently in clinical practice. AIM OF THE REVIEW: This overview aims to characterize and discuss the most commonly used surface conditioning methods based on silanization. The primary chemical features in silane treatment will also be presented. METHOD OF REVIEW: The literature regarding silane utilization was systematically selected and 68 cited references published during 1967-2005 were reviewed. Technical descriptions of different silica-coating (silicatization) methods are presented and some comparative clinical and in vitro experiences are reported. Some other surface condition methods applied in dental laboratories were also selected for presentation. CONCLUSION: It is concluded in this overview tribochemical silica-coating followed by a mandatory silane coupling agent application is a clinically proved, relevant adhesion promotion method to enhance the bonding of resin composites to metallic dental materials.

PMID: 17277821 [PubMed - indexed for MEDLINE]

Sealer penetration and marginal permeability after apicoectomy varying retrocavity preparation and retrofilling material.

Braz Dent J. 2006;17(4):323-7

Authors: Winik R, Araki AT, Negr&#xE3;o JA, Bello-Silva MS, Lage-Marques JL

Apicoectomy failure is generally related to inappropriate marginal sealing of the retrocavity, which allows percolation of microorganisms and their products from root canal system to periapex. This study evaluated tubular penetration of canal sealers and marginal permeability after retrocavity irradiation with Er;Cr:YSGG laser and retrofilling with MTA or cyanoacrylate. Twenty-two single-rooted teeth were decoronated and endodontically treated, their apical 3 mm were resected and the root ends were retroprepared with a low-speed bur. Twenty roots were randomly assigned to 4 groups (n=5): GI and GII--retrofilling with MTA and cyanoacrylate, respectively; GIII and GIV--retrocavity irradiation with Er;Cr:YSGG laser (2.78 microm, 4 W, 20 Hz, 70.8 J/cm(2)) and retrofilling with MTA and cyanoacrylate, respectively. The remaining 2 roots served as positive and negative controls. The analysis of rhodamine B dye infiltration (p=0.05) demonstrated that laser irradiation and MTA retrofilling presented significantly higher permeability rates (p<0.05). Retrofilling with cyanoacrylate showed significantly lower permeability, either when laser was used or not on retrocavity. SEM analysis depicted more cyanoacrylate penetration through dentinal tubules when compared to MTA, suggesting a more efficient marginal sealing. Based on these results, it may be concluded that cyanoacrylate provided a less permeable retrofilling regardless of the retropreparation method, suggesting a more favorable condition to the establishment of the periapical healing.

PMID: 17262147 [PubMed - indexed for MEDLINE]

Antimicrobial analysis of different root canal filling pastes used in pediatric dentistry by two experimental methods.

Braz Dent J. 2006;17(4):317-22

Authors: Amorim Lde F, Toledo OA, Estrela CR, Decurcio Dde A, Estrela C

The objective of this study was to compare, by two experimental methods, the antimicrobial efficacy of different root canal filling pastes used in pediatric dentistry. The tested materials were: Guedes-Pinto paste (GPP), zinc oxide-eugenol paste (OZEP), calcium hydroxide paste (CHP), chloramphenicol + tetracycline + zinc oxide and eugenol paste (CTZP) and Vitapex. Fiven microbial strains (S. aureus, E. faecalis, P. aeruginosa, B. subtilis and C. albicans) obtained from the American Type Culture Collection were inoculated in Brain Heart Infusion (BHI) and incubated at 37 degrees C for 24 h. For the direct exposure test (DET), 72 paper points were contaminated with the standard microbial suspensions and exposed to the root canal filling pastes for 1, 24, 48 and 72 h. The points were immersed in Letheen Broth (LB), followed by incubation at 37 degrees C for 48 h. An inoculum of 0.1 mL obtained from LB was then transferred to 7 mL of BHI, under identical incubations conditions and the microbial growth was evaluated. The pastes showed activity between 1 and 24 h, depending on the material. For the agar diffusion test (ADT), 30 Petri plates with 20 mL of BHI agar were inoculated with 0.1 mL of the microbial suspension, using sterile swabs that were spread on the medium. Three cavities were made in each agar plate (total = 90) and completely filled with one of the filling root canal pastes. The plates were pre-incubated for 1 h at room temperature and then incubated at 37 degrees C for 24 to 48 h. The inhibition zone around each well was recorded in mm. The complete antimicrobial effect in the direct exposure test was observed after 24 h on all microbial indicators. All root canal filling materials induced the formation of inhibition zones, except for Vitapex (range, 6.0-39.0 mm).

PMID: 17262146 [PubMed - indexed for MEDLINE]

Effect of surface treatment on the shear bond strength of a resin-based cement to porcelain.

Braz Dent J. 2006;17(4):290-5

Authors: Nagayassu MP, Shintome LK, Uemura ES, Ara&#xFA;jo JE

The purpose of this in vitro study was to evaluate the effect of different surface treatments on the shear bond strength of a resin-based cement to porcelain. Sixty pairs of 50% aluminous porcelain discs were fabricated. In each pair, one disc measured 6 mm in diameter X 3 mm thickness (A) and the other measured 3 mm in diameter X 3mm thickness (B). The specimens were randomly assigned to 6 groups (n=10 pairs of discs), according to the surface treatment: etching with 10% hydrofluoric acid for 2 or 4 min (G1 and G2); 50-microm particle aluminum oxide sandblasting for 5 s (G3); sandblasting followed by etching for 2 or 4 min (G4 and G5) and control--no treatment (G6). A silane agent was applied to the treated surface of both discs of each pair. Bistite II DC dual-cure resin cement was applied and the B discs were bonded to their respective A discs. Specimens were stored in distilled water at 37 degrees C for 24 h and were tested in shear strength at a crosshead speed of 2 mm/min. Means in MPa were: G1: 14.21 +/- 4.68; G2: 8.92 +/- 3.02; G3: 10.04 +/- 2.37; G4: 12.74 +/- 5.15; G5: 10.99 +/- 3.35; G6: 6.09 +/- 1.84. Data were compared by one-way ANOVA and Tukey's test at 5% significance level. Bond strength recorded after 2-min acid etching was significantly higher than 4-min etching (p<0.05) and control (p<0.05), but did not differ significantly from sandblasting alone (p>0.05) or followed by etching for 2 or 4 min (p>0.05). Within the limitations of an in vitro study, it may be concluded that 2-min hydrofluoric acid etching produced a favorable micromechanical retention that enhanced resin cement bond strength to porcelain.

PMID: 17262141 [PubMed - indexed for MEDLINE]

Polishing methods of an alumina-reinforced feldspar ceramic.

Braz Dent J. 2006;17(4):285-9

Authors: Bottino MC, Valandro LF, Kantorski KZ, Bressiani JC, Bottino MA

The purpose of this study was to test the hypothesis that mechanical polishing methods of ceramic surfaces allow similar superficial roughness to that of glazed surfaces. Twenty-five Vitadur Alpha ceramic discs (5 mm x 2 mm) were prepared according to the manufacturer's specifications. All specimens were glazed and randomly assigned to 5 groups (n=5), according to finishing and polishing protocols: G1: glazed (control); G2: diamond bur finishing; G3: G2 + silicon rubber tip polishing; G4: G3 + felt disc/diamond polishing paste; G5: G3 + felt disc impregnated with fine-particle diamond paste. Next, surface roughness means (Ra - microm) were calculated. Qualitative analysis was made by scanning electron microscopy. Surface roughness data were submitted to ANOVA and Tukey's test at 5% significance level. G1 and G4 were statistically similar (p>0.05). G2 presented the highest roughness means (p<0.05) followed by groups G3, G5, G4 and G1 in a decreasing order. The hypothesis was partially confirmed as only the mechanical polishing (G4) produced similar superficial roughness to that of surface glazing, although finishing and polishing are technically critical procedures.

PMID: 17262140 [PubMed - indexed for MEDLINE]

Collagen analysis in human tooth germ papillae.

Braz Dent J. 2006;17(3):208-12

Authors: Abrah&#xE3;o IJ, Martins MD, Katayama E, Antoniazzi JH, Segmentilli A, Marques MM

The extracellular matrix (ECM) performs a very important role in growth regulation and tissue differentiation and organization. In view of this, the purpose of this study was to analyze the collagen, the major organic component of dental pulp ECM, in papillae of human tooth germs in different developmental phases. The maxillas and mandibles of 9 human fetuses ranging from 10 to 22 weeks of intrauterine life were removed and 16 tooth germs (1 in the cap stage, 8 in the early bell stage and 7 in the late bell stage) were obtained. The pieces were processed for histological analysis and stained with hematoxylin-eosin, Masson's Trichrome and picrosirius staining technique. Both types of collagen in the dental papilla were only detected by the picrosirius staining technique under polarized light microscopy. Type III collagen was detected in all specimens. Type I collagen was present in focal areas of the dental papilla only in some specimens. In conclusion, the findings of this study showed that type III collagen is a regular component of the papillae of human tooth germs whereas type I collagen is present in a significantly lesser amount.

PMID: 17262126 [PubMed - indexed for MEDLINE]

Effect of microwave disinfection on denture base adaptation and resin surface roughness.

Braz Dent J. 2006;17(3):195-200

Authors: Sartori EA, Schmidt CB, Walber LF, Shinkai RS

This study evaluated the effect of disinfection methods [chemical disinfection (immersion in 100 ppm chloride solution) or microwave disinfection (690 W for 6 min)] on the internal adaptation of denture bases and resin surface roughness. For the adaptation test, 18 maxillary denture bases were obtained from stone casts duplicated from a metallic master model and submitted to the following treatments: 1) control (no disinfection), 2) chemical disinfection or 3) microwave disinfection. Disinfection procedures were performed twice (T1, T2) with a 7-day interval between them. Internal adaptation was measured at baseline (T0) and after T1 and T2 by weighing a vinyl polysiloxane film reproducing the gap between the resin base and the master model. For surface roughness measurement, 60 rectangular (5x10x40 mm) resin specimens were either mechanically or chemically polished and then submitted to the disinfection treatments. Surface roughness (Ra) was recorded after polishing (T0) and after T1 and T2. Data were analyzed by ANOVA GLM for repeated measures and Bonferroni correction at 5% significance level. Bases submitted to microwave disinfection had gradual increase of misfit, while bases immersed in chloride solution did not differ from the control group. Surface roughness increased in the mechanical polishing groups with microwave disinfection and decreased in the chemical polishing groups.

PMID: 17262124 [PubMed - indexed for MEDLINE]

Effect of refrigeration on bond strength of self-etching adhesive systems.

Braz Dent J. 2006;17(3):186-90

Authors: Borges GA, Spohr AM, de Oliveira WJ, Correr-Sobrinho L, Correr AB, Borges LH

The purpose of this study was to investigate the tensile bond strength to dentin of three self-etching adhesive systems at refrigerated and room temperatures. Seventy-eight bovine incisors were embedded in self-cured acrylic resin, abraded on a water-cooled lathe and polished with 400- and 600-grit sandpapers to obtain standard dentin surfaces. The specimens were randomly assigned to 6 groups (n=13). Clearfil SE Bond, AdheSE and One-Up Bond F adhesive systems at refrigerated (4 degrees C) and room temperatures (23 degrees C) were applied to dentin according to the manufacturers' instructions. A truncated composite resin (Herculite XRV) cone was bonded to dentin surface. The specimens were stored in distilled water at 37 degrees C for 24 h and submitted to tensile bond strength testing at a crosshead speed of 0.5 mm/min. Means in MPa were analyzed statistically by Student's t-test at 5% significance level. No statistically significant differences (p>0.05) were found between the adhesive systems applied at refrigerated and room temperatures. In conclusion, no adverse effects on tensile bond strength were observed when self-etching adhesive systems were used after being taken directly from the refrigerated storage.

PMID: 17262122 [PubMed - indexed for MEDLINE]

Morphological characterization of the tooth/adhesive interface.

Braz Dent J. 2006;17(3):179-85

Authors: Moura SK, Santos JF, Ballester RY

The purpose of this study was to assess the morphological characteristics of the tooth/adhesive interface using different adhesive systems in MOD restorations under scanning electron microscopy (SEM). The tested hypothesis was that the morphology of the bonding interface would vary in different areas of MOD restorations for the three adhesive systems. MOD cavities were prepared in 12 sound extracted human third molars and restored with Filtek Z250 composite resin and one of the following adhesive systems: Experimental ABF (n=4), Clearfil SE Bond (n=4) self-etching primers and Single Bond etch-and-rinse adhesive system (n=4). After 24-h storage in distilled water at 37 degrees C, teeth were sectioned and prepared for SEM. The interfacial morphology varied depending on the adhesive system and also on the evaluated area. The null hypothesis was accepted because the morphology of the tooth/adhesive interface reflected the characteristics of both the dental substrate and the adhesive systems.

PMID: 17262121 [PubMed - indexed for MEDLINE]

Retention of radicular posts varying the application technique of the adhesive system and luting agent.

Braz Oral Res. 2006 Oct-Dec;20(4):347-52

Authors: Fonseca TS, Alfredo E, Vansan LP, Silva RG, Sousa YT, Saquy PC, Sousa-Neto MD

This study evaluated in vitro the retention of intracanal cast posts cemented with dual-cure resin varying the application method of the primer/adhesive solution and luting agent in the prosthetic space prepared to receive the posts. Sixty endodontically treated maxillary canines had their crowns discarded, and their roots were embedded in acrylic resin. The prosthetic spaces were prepared with Largo burs mounted on a low-speed handpiece coupled to a parallelometer in order to maintain length and diameter of intraradicular posts constant and to guarantee that the preparations were parallel after casting. Two groups (n = 30) were randomly formed according to the device used to apply the adhesive system: microbrush or standard bristle brush (control). Each group was divided into 3 subgroups (n = 10) according to the technique used to place the luting agent into the root canal: using only a lentulo spiral before setting the post, applying it onto the post surface, or combining both methods. After 72 hours, the tensile force required to dislodge each post was determined by a universal testing machine (Instron 4444) set at a speed of 1 mm/min. The results indicated that the use of the microbrush yielded higher bond strength values (0.1740 +/- 0.04 kN) than those recorded for the bristle brush tip (0.1369 +/- 0.04 kN, p < 0.001). Bonferroni's test demonstrated a higher retention (p < 0.001) in radicular post cemented with the technique that combined both methods (lentulo + post: 0.1787 +/- 0.03 kN) than that obtained with lentulo (0.1461 +/- 0.065 kN) or post (0.1416 +/- 0.03 kN) alone. The interactions between the adhesive system and luting agent application techniques presented statistical difference (p < 0.001). It was concluded that the best performance in terms of tensile strength among the tested conditions was obtained when the adhesive system was applied with a microbrush and the luting agent was taken into the root canal with lentulo spirals alone (0.1961 +/- 0.04 kN) and combining both methods (lentulo + post: 0.1911 +/- 0.02 kN).

PMID: 17242797 [PubMed - indexed for MEDLINE]

Hardness of a bleaching-shade resin composite polymerized with different light-curing sources.

Braz Oral Res. 2006 Oct-Dec;20(4):337-41

Authors: Gomes GM, Calixto AL, Santos FA, Gomes OM, D'Alpino PH, Gomes JC

The microhardness of a bleaching-shade resin composite polymerized with different light-curing units was evaluated. Composite samples (3M ESPE Filtek Supreme) were applied to brass rings (2 mm in thickness, 5 mm in diameter). Three commercial LED lights were used to polymerize the specimens and the results were compared to those of a conventional halogen light. The light sources used in the present study were: Demetron Optilux 401 (QTH), 3M ESPE Elipar FreeLight (LED 1); Kerr L.E.Demetron I (LED 2), and ColtoluxLED lights (LED 3). The microhardness of the top and bottom surfaces was assessed with a digital Vickers hardness-measuring instrument, under load. At the bottom surface, no significant difference among the light sources was observed (two-way ANOVA). At the top surface, the QTH light source presented significantly higher hardness values compared to the values observed when LED 1 and LED 3 were used. There were no significant differences between the QTH and LED 2 light sources. Significantly higher hardness values were also found at the top surface when compared to the values observed at the bottom surface. The power density of the polymerization light sources seemed to be responsible for the observed resin composite hardness, not their irradiance.

PMID: 17242795 [PubMed - indexed for MEDLINE]

Densitometric analysis of the autogenous demineralized dentin matrix on the dental socket wound healing process in humans.

Braz Oral Res. 2006 Oct-Dec;20(4):324-30

Authors: Gomes MF, Abreu PP, Morosolli AR, Ara&#xFA;jo MM, Goulart MG

The aim of this study was to evaluate the effects of the autogenous demineralized dentin matrix (ADDM) on the third molar socket wound healing process in humans, using the guided bone regeneration technique and a polytetrafluoroethylene barrier (PTFE). Twenty-seven dental sockets were divided into three groups: dental socket (Control), dental socket with PTFE barrier (PTFE), and dental socket with ADDM slices associated to PTFE barrier (ADDM + PTFE). The dental sockets were submitted to radiographic bone densitometry analysis and statistical analysis on the 15th, 30th, 60th and 90th days using analysis of variance (ANOVA) and Tukey's test (p < or = 0.05). The radiographic analysis of the ADDM + PTFE group showed greater homogeneity of bone radiopacity than the Control group and the PTFE group, during all the observation times. The dentin matrix gradually disappeared from the dental socket during the course of the repair process, suggesting its resorption during the bone remodeling process. It was concluded that the radiographic bone density of the dental sockets treated with ADDM was similar to that of the surrounding normal bone on the 90th day. The ADDM was biocompatible with the bone tissue of the surgical wounds of human dental sockets. The radiographic analysis revealed that the repair process was discreetly faster in the ADDM + PTFE group than in the Control and PTFE groups, although the difference was not statistically significant. In addition, the radiographic image of the ADDM + PTFE group suggested that its bone architecture was better than that of the Control and PFTE groups.

PMID: 17242793 [PubMed - indexed for MEDLINE]

In vitro evaluation of the antimicrobial activity of endodontic sealers.

Braz Oral Res. 2006 Oct-Dec;20(4):303-6

Authors: Miyagak DC, de Carvalho EM, Robazza CR, Chavasco JK, Levorato GL

The purpose of this study is to evaluate the antimicrobial activity of the endodontic sealers: N-Rickert, Sealapex, AH Plus, Mineral Trioxide Aggregate (MTA) and portland cement. The Agar diffusion method was used in plates previously inoculated with the following microorganisms: C. albicans, S. aureus, E. faecalis, E. coli. The diameters of microbial inhibition zones were measured after 24 hours of incubation in kiln at 37 degrees C. According to the methodology used, it was possible to conclude that only the sealers AH Plus and N-Rickert presented antimicrobial activity against C. albicans, S. aureus, and E. coli; no antimicrobial activity in MTA, Sealapex and portland cement was observed. N-Rickert presented the largest inhibition zones varying from 8 to 18 mm, and the microorganism E. faecalis was resistant against all sealers tested.

PMID: 17242789 [PubMed - indexed for MEDLINE]

Porcelain laminate veneer restorations bonded with a three-liquid silane bonding agent and a dual-activated luting composite.

J Oral Sci. 2006 Dec;48(4):261-6

Authors: Matsumura H, Aida Y, Ishikawa Y, Tanoue N

This clinical report describes the fabrication and bonding of porcelain laminate veneer restorations in a patient with anterior open spaces. Laminate veneer restorations made of feldspathic porcelain were etched with 5% hydrofluoric acid, rinsed under tap water, ultrasonically cleaned with methanol, and primed with a chemically activated three-liquid silane bonding agent (Clearfil Porcelain Bond). The enamel surfaces were etched with 40% phosphoric acid, rinsed with water, and primed with a two-liquid bonding agent (Clearfil New Bond) that contained a hydrophobic phosphate (10-methacryloyloxydecyl dihydrogen phosphate; MDP). The restorations were bonded with a dual-activated luting composite (Clapearl DC). The veneers have been functioning satisfactorily for an observation period of one year. Combined use of the Clearfil bonding agents and Clapearl DC luting composite is an alternative to conventional materials for seating porcelain laminate veneer restorations, although the system is inapplicable to dentin bonding.

PMID: 17220627 [PubMed - indexed for MEDLINE]

Effect of metal priming agents on bonding characteristics of an acrylic resin joined to SUS XM27 steel.

J Oral Sci. 2006 Dec;48(4):215-8

Authors: Ishikawa Y, Kawamoto Y, Koizumi H, Furuchi M, Matsumura H, Tanoue N

The purpose of the current study was to evaluate the effect of functional monomers contained in the primers on adhesive bonding of a steel alloy. SUS XM27 steel was primed with one of the following materials; Alloy Primer, Estenia Opaque Primer, and V-Primer. The functional monomers in the primers were a phosphate (10-methacryloyloxydecyl dihydrogen phosphate; MDP) and a thione (6-(4-vinylbenzyl-n-propyl) amino-1,3,5-triazine-2,4-dithione, -dithiol tautomer; VTD) for Alloy Primer, MDP alone for Estenia, and VTD alone for V-Primer. The steel disks were bonded with an acrylic resin (Unifast Trad), and bond strength was determined. Of the three primers, both the Alloy Primer (33.3 MPa) and Estenia Opaque Primer (33.9 MPa) materials exhibited far better post-thermocycling bond strength than V-Primer (0 MPa). It can be concluded that the phosphate MDP is effective, whereas the thione VTD is ineffective for bonding SUS XM27 steel.

PMID: 17220619 [PubMed - indexed for MEDLINE]

Biocompatibility of natural latex implanted into dental alveolus of rats.

J Oral Sci. 2006 Dec;48(4):201-5

Authors: Balabanian CA, Coutinho-Netto J, Lamano-Carvalho TL, Lacerda SA, Brentegani LG

The present study investigated the biocompatibility of a biopolymer based on vegetable latex extracted from the Hevea brasiliensis rubber tree, implanted into the bony alveolar cavity after dental extraction in rats. A granule of latex (area = 0.25 +/- 0.04 mm(2)) was implanted inside the alveolus immediately after extraction of the upper right incisor, and the animals were sacrificed 7, 21 and 42 days after the procedure. The hemi-maxillas were decalcified and processed for embedding in paraffin to obtain semi-serial longitudinal sections 5 mum thick, and then stained with hematoxylin-eosin. The latex granule was observed in the cervical third of the alveolus without any foreign body reaction, or persistence of the initial acute inflammatory reaction. Bone repair in the areas adjacent to the material was quantified, and a decrease was noted in the thickness of the fibrous capsule surrounding the implants from 92.8 +/- 9.3 microm on day 7 to 9.4 +/- 1.8 microm on day 42 (ANOVA, P = 0.01). The quantitative data confirmed acceleration of bone formation (statistically significant at 5%) in parallel with a decrease of connective tissue in the areas around the implants. These results show that the tested material is biologically compatible, and progressively integrated into the alveolar bone, simultaneously accelerating bone formation and playing an important role in the healing process.

PMID: 17220617 [PubMed - indexed for MEDLINE]

Diabetes and its effects on dental pulp.

J Oral Sci. 2006 Dec;48(4):195-9

Authors: Catanzaro O, Dziubecki D, Lauria LC, Ceron CM, Rodriguez RR

Uncontrolled or poorly controlled diabetes mellitus may be a risk factor for the development of oral complications. The objective of this investigation was to determine the effect of diabetes mellitus progression on inflammatory and structural components of dental pulp. Male Wistar rats were given a single injection of Streptozotocin (STZ), and induction of diabetes was confirmed 24 h later. Dental pulp tissue samples were taken from central incisors and molars of diabetic rats 30 and 90 days after the STZ treatment. Plasma glucose levels in diabetic rats 30 and 90 days after STZ treatment were significantly increased when compared to control rats (P < 0.001). Nitrite and kallikrein levels in dental pulp tissue were higher in diabetic rats 30 days after STZ treatment than in controls, while only nitrite were decreased 90 after of STZ treatment. Myeloperoxidase activity showed changes 30 and 90 days after STZ injection when compared to controls. The activity of alkaline phosphatase showed significant changes 30 and 90 days after STZ treatment. On the other hand the concentration of collagen was decreased in diabetic rats 30 and 90 days after STZ injection. These results suggest that diabetes is a critical factor that has profound effects upon oral tissues, resulting in expression of inflammatory mediators and modifications of structural components of dental pulp.

PMID: 17220616 [PubMed - indexed for MEDLINE]