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]

A method of gauging dental radiographs during treatment planning for dental implants.

J Contemp Dent Pract. 2007;8(6):82-8

Authors: Anil S, Al-Ghamdi HS

AIM: The goal of pre-surgical dental implant treatment planning is to position the optimum number and size of implant fixtures to achieve the best restorative results. The purpose of this article is to describe the use of radiographic imaging software to calibrate and measure anatomical landmarks to overcome inherent distortions associated with dental radiographs. The procedure along with its potential use as an adjunct to radiographic interpretation in routine clinical implant practice is presented. BACKGROUND: Diagnostic imaging is an essential component of implant treatment planning, and a variety of advanced imaging modalities have been recommended to assist the dentist in assessing potential sites for implants. Although technological advances have resulted in new imaging innovations for implant dentistry, dental radiography remains the most widely used tool for determining the quantity and quality of alveolar bone as it is a non-invasive procedure. However, the unreliable magnification factor associated with conventional radiographs remains a major problem when estimating the amount of bone available at the implant site. SUMMARY: This image measurement technique is capable of assessing the bone quantity by measuring the height and width of the alveolar crest for a specified region in a two dimensional plane in any direction related to the visible landmarks in the oral cavity. These measurements can be used by the clinician to select the type of implant and its position. Since there is no additional equipment or cost involved, the technique can be used as an important adjunct in implant practice.

PMID: 17846675 [PubMed - indexed for MEDLINE]

Augmentation in two stages of atrophic alveolar bone prior to dental rehabilitation: a case report.

J Contemp Dent Pract. 2007;8(6):57-63

Authors: Zahrani AA

AIM: The aim of this report is to describe a significantly deficient case of alveolar bone that was managed by alveolar bone augmentation using a technique of distraction osteogensis and onlay bone grafting prior to dental implant placement. BACKGROUND: Injury to the teeth and alveolar ridge of the maxillary anterior region can cause a severe alveolar ridge deficiency resulting in ridge atrophy and maxillary retrognathism. The loss of these teeth and alveolar bone together with fibrotic scar formation can result in adverse changes of the interarch space, occlusal plane, arch relationship, and arch form which complicates rehabilitation and can compromise the esthetic outcome. While implant dentistry has become a new paradigm in oral reconstruction and replacement of missing teeth, ideal implant positioning can be compromised by inadequate alveolar bone in terms of bone height, width, and quality of the bone itself. Correction of osseous deficiencies with ridge augmentation allows ideal implant placement and creates a more natural soft tissue profile which influences crown anatomy and esthetics. REPORT: A 20-year-old female presented with a complaint of poor esthetics resulting from oral injuries incurred in a traffic accident six years previously. In addition to a mandibular parasymphyseal fracture, five maxillary anterior teeth and the most of the alveolar ridge were lost. Clinical examination revealed severe loss of bone in the maxillary anterior region, an absence of a labial sulcus, loss of upper lip support, and a slight over eruption of the mandibular anterior teeth. In preparation for dental implants a distraction osteogenesis surgical procedure was done to lengthen the height of the alveolar ridge. After a three-month healing period, the width of the residual ridge was found to be insufficient for implant placement. To correct this deficiency, a bone graft of a cortiocancellous block was harvested from the chin and fixed to the labial aspect of the ridge. To facilitate revascularization, small perforations were made in the cortical bone of the alveolar ridge at the recipient site before cancellous bone retrieved from the donor site was gently placed between the bone block and the ridge. The patient was then appropriately medicated and healing was uneventful. After three months, the width of the residual ridge was assessed to be adequate for endosseous implants. SUMMARY: The clinical result reported here has shown several procedures may be necessary for the rehabilitation of a trauma patient. Distraction osteogenesis per se may not always satisfactorily improve the anatomical alveolar anatomy but it has advantages over other methods of augmentation. It can improve the height and also expand the soft tissue for further bone grafting. Augmentation of the alveolar bone with an onlay bone graft often provides the desired gain of bone, allows for the ideal placement of dental implants, and improves any discrepancy between the upper and lower arches.

PMID: 17846672 [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]

Pre-operative drilling simulation method for dental implant treatment.

Bull Tokyo Dent Coll. 2007 Feb;48(1):27-35

Authors: Arataki T, Furuya Y, Ito T, Miyashita Y, Shimamura I, Yajima Y

The position, depth and direction of implant placement are often planned based on evaluation of radiographs and study casts. Insertion planned in such a manner may not be adequate for precise and safe surgery in some cases due to inadequate working clearance in the oral cavity. In order to obtain high initial stability and ensure osseointegration at the implant-bone interface, careful and precise drilling must be performed at the implant placement site. Therefore, we propose the necessity of evaluating the operability of implant treatment-devices prior to surgery. The amount of handling space needed during implant placement surgery was determined. The results showed that for implants with a length of 7-18 mm, a vertical distance of as much as 50-60 mm was required, depending on the implant platform. These results suggest the necessity of pre-operative drilling simulation in each individual. Handling space was measured with angled heads and probes fabricated on a trial basis for pre-surgical drilling simulation in the oral cavity. We believe that these instruments may be clinically useful in estimating the amount of handling space required prior to surgery and ensuring precise implant placement. Evaluation of the intra-oral environment for handling of treatment devices should be included in the pre-surgical intra-oral evaluation of dental implant cases to avoid changes in treatment planning due to intra-oral interference during the course of surgery.

PMID: 17721064 [PubMed - indexed for MEDLINE]

Facemask therapy with miniplate implant anchorage in a patient with maxillary hypoplasia.

Chin Med J (Engl). 2007 Aug 5;120(15):1372-5

Authors: Zhou YH, Ding P, Lin Y, Qiu LX

PMID: 17711747 [PubMed - indexed for MEDLINE]

Denture-induced fibrous hyperplasia. Treatment with carbon dioxide laser and a two year follow-up.

Indian J Dent Res. 2007 Jul-Sep;18(3):135-7

Authors: Naveen Kumar J, Bhaskaran M

Denture-induced fibrous hyperplasia (DIFH) is a persistent lesion caused mostly by the prolonged wear of an ill-fitting, over-extended denture. Although the condition frequently coexists with denture stomatitis, it is a distinct entity with a different protocol for management. The article describes successful treatment for a case of DIFH using carbon dioxide laser and a two year follow-up. The inherent advantages of using carbon dioxide laser over conventional surgical techniques are discussed.

PMID: 17687178 [PubMed - indexed for MEDLINE]

Complete denture impression techniques: evidence-based or philosophical.

Indian J Dent Res. 2007 Jul-Sep;18(3):124-7

Authors: Singla S

Code of practice is dangerous and ever-changing in today's world. Relating this to complete denture impression technique, we have been provided with a set of philosophies--"no pressure, minimal pressure, definite pressure and selective pressure". The objectives and principles of impression-making have been clearly defined. Do you think any philosophy can satisfy any operator to work on these principles and achieve these objectives? These philosophies take into consideration only the tissue part and not the complete basal seat, which comprises the periphery, the tissues and the bone structure. Under such circumstances, should we consider a code of practice dangerous or should we develop an evidence-based approach having a scientific background following certain principles, providing the flexibility to adapt to clinical procedures and to normal biological variations in patients rather than the rigidity imposed by strict laws?

PMID: 17687175 [PubMed - indexed for MEDLINE]

Infections in implantology: from prophylaxis to treatment.

Med Oral Patol Oral Cir Bucal. 2007 Aug;12(4):E323-30

Authors: Bowen Antolín A, Pascua García MT, Nasimi A

Since the introduction of osseointegrated implant treatment, odontology, and in particular the area of prosthodontic replacement of lost teeth, has evolved in an unimaginable way, to the extent that the age-old idea of "restitutio ad integrum" has almost become possible. Implant treatment has a high success rate that has been rated as high as 95 to 99%, according to different casuists, but there is another group of cases in which implants fail, and in fact it is hard to know the causes of such failures. The microbiological component plays an important role in encouraging and facilitating implant infection during implant placement, and also later when the implant is in function in the mouth, which is a septic medium. In this paper we will study infections in implantology, classified according to the treatment phase: Infection prior to the implant; Peri-surgical infection; Severe post-surgical infection; Peri-implant disease.

PMID: 17664920 [PubMed - indexed for MEDLINE]

Management of exaggerated gag reflex using intravenous sedation in prosthodontic treatment.

Tohoku J Exp Med. 2007 Aug;212(4):373-8

Authors: Yoshida H, Ayuse T, Ishizaka S, Ishitobi S, Nogami T, Oi K

The gag reflex is a somatic natural response in which the body attempts to eliminate instruments or agents from the oral cavity by muscle contraction. Some patients suffered from such severe retching that behavioral techniques did not sufficiently reduce gagging in dentistry. In these patients, pharmacological management was thought to be the last alternative to eliminate the reflex. However, the potential of intravenous (IV) sedation as a way to overcome problems in gagging management during prosthodontic (prosthetic) therapy has not been sufficiently explored. We examined the benefit of IV sedation to facilitate prosthodontic treatment for problematic gagging patients intolerable to dental therapy. The subjects were 10 severely retching patients (7 males and 3 females) who received prosthodontic or restorative therapy under propofol IV sedation. The number, location and prognosis of dentures/restorations were reviewed retrospectively. Eight dentures (3 removable and 5 fixed partial dentures) and 22 restorations (18 crowns and 4 inlays) were seated successfully in the oral cavity without serious complications related to IV sedation. The restored teeth were located predominantly in the posterior regions. Throughout the observation period of at least 6 months, no symptoms of postoperative pain or swelling were found. Five of the 10 patients showed improved tolerance to oral inspection, indicating a behavioral adjustment to dental care. In prosthodontic treatment extended to the posterior regions, propofol IV sedation proved useful in managing reflex control.

PMID: 17660702 [PubMed - indexed for MEDLINE]

Rehabilitation of a marginal mandibulectomy patient using a modified neutral zone technique: a case report.

Braz Dent J. 2007;18(1):83-6

Authors: Pekkan G, Hekimoglu C, Sahin N

Anterior edentulous areas usually display unusual soft tissue configurations and compromised bone support in patients with marginal mandibulectomy. There are several treatment modalities for these patients. A removable partial denture may be the treatment of choice. Maximum stability of the partial denture base for mandibulectomy patients may be accomplished by the application of the neutral zone concept, which helps providing stability to the base. This case report describes the fabrication of a removable partial denture for a patient with marginal mandibulectomy using a modified neutral zone technique.

PMID: 17639208 [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]

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]

Ingestion of a fixed partial denture during general anesthesia.

Anesth Prog. 2007;54(2):50-1

Authors: Neustein S, Beicke M

Dental trauma during anesthesia is a common occurrence. Many patients have had extensive dental work, which is more fragile than the natural dentition. This work may include crowns, fixed partial dentures (bridges), and porcelain veneers. We report for the first time, a case in which a fixed partial denture became dislodged and was ingested, and was recovered postoperatively with endoscopy.

PMID: 17579503 [PubMed - indexed for MEDLINE]

Stabilization of an abutment under a rigidly fixed bridge by holographical-speckle interferometry.

J Zhejiang Univ Sci B. 2007 Jun;8(6):416-21

Authors: Zhang YZ, Zhou YC, Liu L, Lu Y, Hirofumi Y

OBJECTIVE: There are no detailed reports of three-dimensional measurement of abutment teeth in mastication, because it is knotty to observe the rotation in chewing directly, and inexact to estimate indirectly. This work studies the three-dimensional stability of rigidly fixed bridge under the stresses of distributed loads and concentrated loads by optical method that gives the tip angle and rotation angle calculated directly based on measurement data. METHODS: The specimen, taken from a 25-year-old male, was a left mandible without the second premolars and the first molars. As abutments, first premolar and second molar have complete periodontium. The specimen was soaked in formaldehyde solution. The bridge was fixed between two abutment teeth (first premolars and second molars), and the mandible was cemented in a steel box. The load was increased from 0 kg to 23 kg. Laser holographic technique was used to measure the three-dimensional bit shift of the dens, both buccolingual bit shift and mesiodistal bit shift, and determine tip angle and rotation angle. RESULTS: The effects of stress distribution on the rigidly fixed bridge were evaluated, and stabilization of the bridge under the stresses of distributed loads and concentrated loads, respectively, were analyzed. The results showed that the tips of two abutments were very similar, and no distinct difference was observed between the distributed load and the concentrated load. However, the maximum rotation angle for the distributed load was two to four times as large as that for the concentrated load. In the experiment, the tip angle of the abutment teeth was no more than 0.65 degree, and the rotation angle was no more than 0.60 degree. All maximum angles occurred in the second molar. CONCLUSION: The fixed bridge is considered to be safe. In addition, a method for measuring the rotation angle was provided effectively.

PMID: 17565512 [PubMed - indexed for MEDLINE]

[Health complaints related to dental filling materials]

Tidsskr Nor Laegeforen. 2007 May 31;127(11):1524-8

Authors: Lygre GB, Helland V, Gjerdet NR, Bj&#xF6;rkman L

BACKGROUND: A wide range of materials is used in dental treatment. To what extent these materials lead to adverse reactions is under dispute. The aim of this study was to investigate whether patients with suspected adverse reactions to dental materials experienced an improvement in health after these materials were replaced. MATERIAL AND METHODS: Information on health complaints related to dental materials was obtained from the Dental Biomaterials Adverse Reaction Unit in Bergen, Norway for 142 patients. A follow-up questionnaire regarding subjective health was sent to these patients 1(1/2) to 2(1/2) years later. A similar questionnaire was sent to a reference group of 800 persons drawn from the general population. RESULTS: The patient group had more health complaints than the reference group (p < 0.001) at baseline. Of the 84 patients who completed the questionnaire (59%) 35 had changed dental materials. Amalgam fillings had been replaced in most of these patients. 23 patients (66%) reported improved health after replacement. Intraoral complaints decreased significantly (p = 0.022), and were most pronounced in patients with lesions in contact with dental materials. The intensity of various health complaints decreased slightly in most patients with replaced dental materials, but the patient group still had significantly higher health complaint indices than the reference group. INTERPRETATION: The intensity of subjective health complaints was reduced after replacement of dental materials, but it was still higher than for a comparable group in the general population. The results indicate that there may be a specific health effect of replacing dental materials, but normal symptom fluctuations over time and placebo effects such as positive effects from expectations and general care from the health personnel may have had an influence.

PMID: 17551559 [PubMed - indexed for MEDLINE]

Perceptibility and acceptability of CIELAB color differences in computer-simulated teeth.

J Dent. 2007 Jul;35(7):593-9

Authors: Lindsey DT, Wee AG

OBJECTIVES: To determine the perceptibility and acceptability of tooth color differences using computer-generated pairs of teeth with simulated gingival displayed on a calibrated color monitor using appropriate signal detection theory methodology (SDT). METHODS: Twelve dental professionals (four from each of the following groups: dentists, dental auxiliaries, and fixed prosthodontic technicians) and four dental patients served as subjects. Responses to tooth color differences (DeltaE) were measured on each of the three principal axes of CIELAB color space (L*, a*, and b*). As a control, responses to DeltaE=0 (the false alarm rate) were also measured in the same experimental session. RESULTS: No group differences among subjects were found. All gave 50% match or acceptance points that averaged about 1.0 DeltaE units in the L* and a* directions, and 2.6 units in the b* direction. False alarm rates across all subjects averaged 27% (4-55%) and 28% (0.4-61%), respectively, for perceptibility and acceptability. A reanalysis of the data based on SDT, which takes subjects' false alarm rates into account, gave somewhat larger color difference thresholds. CONCLUSIONS: Color difference thresholds for our simulated teeth are generally in line with and extend results obtained with studies using "real" dental materials. No differences between thresholds for acceptability versus perceptibility were found. Furthermore, subjects often reported color differences when none existed, and this behavior needs to be factored into any determination of quality control standards for the fabrication of dental prostheses.

PMID: 17517460 [PubMed - indexed for MEDLINE]

Restoration of a vertical tooth fracture and a badly mutilated tooth using canal projection.

Indian J Dent Res. 2007 Apr-Jun;18(2):87-9

Authors: Velmurugan N, Bhargavi N, Lakshmi N, Kandaswamy D

Management of vertically fractured tooth or a perforation frequently poses problem during endodontic management. Such teeth often need a pre-endodontic restoration prior to initiation of root canal therapy to aid in the placement of rubber dam clamp. This paper describes a simple method of placement of a pre-endodontic restoration using the canal projection technique using hollow metallic needles as sleeves.

PMID: 17502715 [PubMed - indexed for MEDLINE]

Specialty dentistry for the hemophiliac: is there a protocol in place?

Indian J Dent Res. 2007 Apr-Jun;18(2):48-54

Authors: Kumar JN, Kumar RA, Varadarajan R, Sharma N

Restorative dental care for the hemophiliac patient is of paramount importance for the fact that advanced dental conditions and subsequent treatments prove to be more complicated and risky. Quite often, dental health is neglected by hemophiliacs for fear of bleeding during procedures. Surprisingly, even dental specialists avoid these candidates and contribute to the conversion ofa simple dental patient to an oral surgical patient. The complexities involved in diagnosing a bleeding disorder and the rarity of a standardized protocol to handle such patients contribute to this problem. This article prescribes a simple protocol to diagnose bleeding disorders and a modified scheme for endodontic and periodontal therapy in a hemophiliac patient.

PMID: 17502707 [PubMed - indexed for MEDLINE]

Restoring function and esthetics in a patient with amelogenesis imperfecta: a case report.

J Contemp Dent Pract. 2007;8(4):95-101

Authors: Gokce K, Canpolat C, Ozel E

AIM: The purpose of this case report is to present the esthetic and functional rehabilitation of the teeth in a 22-year-old patient with Amelogenesis imperfecta (AI). BACKGROUND: AI is a group of hereditary defects of enamel, unassociated with any other generalized defects. It is a rare developmental abnormality of the enamel, with a variable occurrence of approximately 1:4000 to 1:14000 in Western populations. Al results in poor development or complete absence of the enamel of the teeth caused by improper differentiation of the ameloblasts. REPORT: This report describes the diagnosis and treatment of a young male patient with AI and missing molar teeth using contemporary restorative strategies. Initially, the tooth surfaces were treated with a professional cleaning along with conservative restorative treatment. Later, metal-ceramic crowns for posterior teeth and full-ceramic crowns for anterior teeth were utilized for final restorations. SUMMARY: The complexity of the management of patients with AI supports the suggestion the dental profession should have appropriate methods for the rehabilitation of rare dental disorders. The treatment of patients with AI should start with early diagnosis and intervention to prevent later restorative problems.

PMID: 17486193 [PubMed - indexed for MEDLINE]

Rehabilitation of severely resorbed maxillae with zygomatic implants: an update.

Med Oral Patol Oral Cir Bucal. 2007 May;12(3):E216-20

Authors: Gal&#xE1;n Gil S, Peñarrocha Diago M, Balaguer Martínez J, Marti Bowen E

Studies highlight the zygomatic bone as a suitable anatomical structure for implant placements since they cross four corticals. Zygomatic implants were described by Branemark in 1988, since then zygomatic implants are indicated in maxillae with atrophy of the posterior area. They have been used in systemic diseases associated with bone loss in this area, and in patients who have suffered radical surgery for maxillofacial tumors. Computed tomography is recommended before placement in order to discount any pathology of the maxillary sinus. The surgical technique has been slightly modified since its description with procedures such as the sinus slot technique. The success rate obtained by different authors varies between 82% and 100%, indicating this technique as a valid treatment option. The objective of this study was to revise the literature with the aim of updating the subject.

PMID: 17468718 [PubMed - indexed for MEDLINE]

[influence and improvement of metal artifacts in dental structures by CT for radiation treatment planning: reconstruction of transverse images using oblique images by gantry tilt scanning]

Nippon Hoshasen Gijutsu Gakkai Zasshi. 2007 Mar 20;63(3):326-34

Authors: Nakae Y, Inoue H, Minamoto T, Yamamoto T, Johkou T

Intensity-modulated radiation therapy (IMRT) radiation treatment planning (RTP) requires accuracy. Metal artifacts are one of the factors that influence RTP. The metal artifacts from dental structures are problems at the level of the oropharynx, since these artifacts impair visualization of tumors or lymph nodes and change CT (computed tomography) values. We simulated RTP at the level of the oropharynx using CT images with and without artifacts from dental structures. Gantry tilt scanning was performed to avoid artifacts from dental structures and transverse images reconstructed from oblique images by gantry tilt scanning using a technique of multiplanar reconstruction (MPR) . The reconstructed transverse images were used for the RTP. The reconstructed transverse images were useful to obtain accurate target volumes and the RTP of two opposed equally weighted beams by correct CT values. As dose distribution was changed slightly by the metal artifacts, the use of CT images without artifact is recommended in RTP.

PMID: 17409624 [PubMed - indexed for MEDLINE]

Denture stomatitis.

Skinmed. 2007 Mar-Apr;6(2):92-4

Authors: Chen AY, Zirwas MJ

A 70-year-old woman presented for evaluation of an eruption localized to the area covered by her partial upper denture. Her medical history and physical examination were otherwise unremarkable. She originally had a metal upper partial denture, which she used for many years without difficulty. Four years before presentation, she developed a painful eruption affecting only the tissue covered by the upper partial denture. Contact dermatitis to metal was suspected, and a new upper partial denture constructed primarily of acrylates was fashioned. When she transitioned to the new denture, the inflammation in her oral mucosa persisted and perhaps worsened, despite an excellent fit. Examination revealed striking erythema and mild edema sharply localized to the areas where the partial upper denture contacted the gum ridge. Patch testing was performed and revealed allergies to multiple acrylates, including methyl methacrylate. A swab from the gums was sent for yeast culture. No Candida was detected. Based on suspected candidal overgrowth on the denture, the patient was advised to begin applying nystatin ointment between the gums and the denture, and to start soaking the dentures nightly in chlorhexidine 0.12% solution. In addition, because the relevance of the acrylate allergy was unclear, her dentist was contacted and it was recommended that the dentures be boiled to induce polymerization of any residual un-reacted methacrylate monomers. The patient had a 90% improvement in the clinical appearance and in symptoms at an 8-week follow-up appointment. Due to logistic issues, the dentures had not yet been boiled. The improvement, despite the dentures not having been boiled, was felt to demonstrate that the acrylate allergy was not relevant. The patient has continued to slowly show further improvement over 6 months of follow-up.

PMID: 17366680 [PubMed - indexed for MEDLINE]

Histological comparison of bone to implant contact in two types of dental implant surfaces: a single case study.

J Contemp Dent Pract. 2007;8(3):29-36

Authors: Shibli JA, Feres M, de Figueiredo LC, Iezzi G, Piattelli A

AIM: The purpose of this single case study was to evaluate the influence of different implant surfaces on human bone and osseointegration. METHODS AND MATERIALS: A 47-year-old partially edentulous woman received two experimental implants along with conventional implant therapy. Experimental implants placed in the mandibular ramus consisted of machined and anodized surfaces, respectively. After three months of healing, the experimental implants were removed and prepared for ground sectioning and histological analysis. RESULTS: The data demonstrate anodized implant surfaces present a higher percentage of osseointegration when compared to a machined surface in cortical human bone after a healing period of three months. CONCLUSION: This single case study suggests an anodized implant surface results in a higher percentage of bone to implant contact when compared to machined surfaced implants when placed in dense bone tissue. However, further investigations should be conducted.

PMID: 17351679 [PubMed - indexed for MEDLINE]

Prosthetic rehabilitation of a completely edentulous patient with palatal insufficiency.

Indian J Dent Res. 2007 Jan-Mar;18(1):35-7

Authors: Bhat AM

This article presents a case report of a completely edentulous patient with palatal insufficiency successfully rehabilitated with closed hollow bulb obturator prosthesis and also describes a simple technique for fabricating a two-piece hollow bulb obturator that allows for control of the bulb's wall thickness and weight of the prosthesis.

PMID: 17347544 [PubMed - indexed for MEDLINE]

Cone-beam CT (CB Throne) applied to dentomaxillofacial region.

Bull Tokyo Dent Coll. 2006 Aug;47(3):133-41

Authors: Yajima A, Otonari-Yamamoto M, Sano T, Hayakawa Y, Otonari T, Tanabe K, Wakoh M, Mizuta S, Yonezu H, Nakagawa K, Yajima Y

Cone-beam CT (CBCT) systems specifically designed for hard-tissue imaging of the maxillofacial region have recently become commercially available. The newly-developed CBCT system, CB Throne (Hitachi Medical Corp., Tokyo), is characterized by a number of features such as low dose, sub-millimeter spatial resolution, and a small footprint. This system has been clinically applied at Chiba Hospital, Tokyo Dental College, since April 2005. This article reports the characteristics of this system, and its diagnostic power for maxillofacial lesions and the pre-operative planning dental implants.

PMID: 17344621 [PubMed - indexed for MEDLINE]

Reliability of linear distance measurement for dental implant length with standardized periapical radiographs.

Bull Tokyo Dent Coll. 2006 Aug;47(3):105-15

Authors: Wakoh M, Harada T, Otonari T, Otonari-Yamamoto M, Ohkubo M, Kousuge Y, Kobayashi N, Mizuta S, Kitagawa H, Sano T

The purpose of this study was to investigate the accuracy of distance measurements of implant length based on periapical radiographs compared with that of other modalities. We carried out an experimental trial to compare precision in distance measurement. Dental implant fixtures were buried in the canine and first molar regions. These were then subjected to periapical (PE) radiography, panoramic (PA) radiography, conventional (CV) and medical computed (CT) tomography. The length of the implant fixture on each film was measured by nine observers and degree of precision was statistically analyzed. The precision of both PE radiographs and CT tomograms was closest at the highest level. Standardized PE radiography, in particular, was superior to CT tomography in the first molar region. This suggests that standardized PE radiographs should be utilized as a reliable modality for longitudinal and linear distance measurement, depending on implant length at local implantation site.

PMID: 17344618 [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]

Positional vertigo afterwards maxillary dental implant surgery with bone regeneration.

Med Oral Patol Oral Cir Bucal. 2007 Mar;12(2):E151-3

Authors: Rodr&#xED;guez Gutiérrez C, Rodríguez Gómez E

Benign paroxysmal positional vertigo (BPPV) is the most common form of vertigo. It is caused by loose otoconia from the utricle which, in certain positions, displaced the cupula of the posterior semicircular canal. BPPV most often is a result of aging. It also can occur after a blow to the head. Less common causes include a prolonged positioning on the back (supine) during some surgical procedures. Additionally one can include in this ethiopathogenesis the positioning required during the maxillary dental implant surgery with bone regeneration related to a forced head positioning and inner ear trauma induced by dental turbine noise working in the maxillary bone. Two cases of patients who suffered BPPV after undergoing maxillary dental implant with bone regeneration procedures are reported. Diagnosis and treatment are also described.

PMID: 17322805 [PubMed - indexed for MEDLINE]

Oral rehabilitation with the new SG attachment in a patient treated for oral squamous cell carcinoma.

Med Oral Patol Oral Cir Bucal. 2007 Mar;12(2):E122-5

Authors: Senent G, Barjau I, Silvestre FJ

In patients who have undergone surgery and radiotherapy for oral squamous cell carcinoma (OSCC), the posterior oral rehabilitation may prove complex. In addition to the defects produced by surgical ablation of the primary tumor, radiotherapy induces deleterious effects upon the oral tissues. We present the case of a 48-year-old male treated two years before due to OSCC in the retromolar trigone and left lateral wall of the oropharynx. Following study of the case with clinical examination and orthopantomography, a management plan was defined involving rehabilitation of the upper dental arch with fixed ceramometallic prostheses, while in the lower arch we chose a unilateral removable prosthesis adapted to a fixed prosthesis by means of a special and versatile attachment based on a new system that functions as a fixed element but which can be removed or changed at some later date. The present clinical case illustrates this type of prosthodontic solution for the management of oncological patients of this kind.

PMID: 17322799 [PubMed - indexed for MEDLINE]

Retrieval of blade implants with piezosurgery: two clinical cases.

Minerva Stomatol. 2007 Jan-Feb;56(1-2):53-61

Authors: Sivolella S, Berengo M, Fiorot M, Mazzuchin M

In this work an ultrasound device was used to perform an ostectomy for the removal of blade implants in order to save as much bone tissue as possible, so that root form implants might later be inserted. Two patients underwent surgery for the removal of two blade implants (one maxillary, the other mandibular) that were no longer functional. The peri-implant ostectomy was carried out with a piezoelectric surgery device. The instrument demonstrated to be effective and precise during ostectomy, providing an extremely thin cutting line. During the course of the operation and at controls after 7 and 30 days, patients did not show any relevant complications and both still had sufficient alveolar bone to be treated with root form implants. The piezosurgery device proved to be an effective instrument in interventions requiring a significant saving of bone tissue, extreme precision in cutting, and respect of soft tissues.

PMID: 17287707 [PubMed - indexed for MEDLINE]

Esthetics and implantology: medico-legal aspects.

Minerva Stomatol. 2007 Jan-Feb;56(1-2):45-51

Authors: Santoro V, De Donno A, Dell'Erba A, Introna F

In recent years the high number of malpractice lawsuits in dentistry has attracted closer attention of dental practitioners to its medico-legal aspects. Implantology, in particular, presents many points of medico-legal concern connected with the difficulties inherent to dental procedures and objectives (both functional and esthetic), as well as full patient collaboration as an essential part of successful treatment. An accurate assessment of each case by the clinician is fundamental, especially in circumstances where esthetic considerations are preponderant as, for instance, in the frontal sectors. In such cases, the options of implantology or of a traditional fixed prosthesis need to be carefully weighed in light of the patient's anatomic condition. The patient should therefore receive complete information and be made fully aware of the risk of treatment failure, as well as possible complications, limits to the procedures, and the fact that successful outcome will also depend on her/his scrupulous observance of the practitioner's instructions. In short, the aim is to make the patient an active ''accomplice'' in treatment. To this end, the use of an extremely detailed information leaflet is strongly advised; after careful clarification of any doubts the patient may have, the patient's written informed consent should be obtained. Nevertheless, there is the risk that excessive intrusion of bureaucracy into medical procedures in defence of the practitioner against malpractice suits may hinder the principal aim of traditional medicine, i.e. to provide the best care for the patient through mutual trust fostered within the doctor-patient relationship.

PMID: 17287706 [PubMed - indexed for MEDLINE]

Measurement of color for craniofacial structures using a 45/0-degree optical configuration.

J Prosthet Dent. 2007 Jan;97(1):45-53

Authors: Gozalo-Diaz DJ, Lindsey DT, Johnston WM, Wee AG

STATEMENT OF PROBLEM: The color of vital craniofacial structures has not been measured accurately. PURPOSE: The purpose of this study was to determine the color of vital craniofacial structures and evaluate the validity and test-retest reliability of a noncontacting 45/0-degree optical configuration. MATERIAL AND METHODS: A spectroradiometer and an external light source were configured in a noncontacting 45/0-degree (45-degree illumination and 0-degree observer) optical configuration to measure the color of subjects' vital craniofacial structures (central and lateral incisor and canine, attached gingiva, lips, and facial skin). The 120 subjects were stratified into 5 age groups with 4 racial categories and balanced for gender. For evaluation of validity, linear regressions and 95% confidence intervals were calculated for DeltaL( *), Deltaa( *), Deltab( *) [color difference of (CIE) LAB values] between the measured and certified values of the 22 color patches of the DC Color Checker. For test-retest reliability, a random sample of 12 (10%) subjects was remeasured at a second visit. Paired t tests, correlations, and Bland-Altman analyses were performed between the first and second measurements of the 12 pairs of L( *), a( *), and b( *) values for the 6 craniofacial structures. RESULTS: For validity, the mean color difference and linear regression for Commission Internationale d'Eclairage (CIE) LAB values between measured and certified color of the 22 opaque color patches were DeltaE of 1.46 and 0.99 for all regressions, respectively. Only Deltaa( *) did not contain zero in its 95% confidence interval. For test-retest reliability, no paired t tests were significantly different from each other, and the Pearson correlation coefficient ranged from 0.9 (9 pairs) to 0.7 (3 pairs). Ten of the 18 Bland-Altman plots showed good reliability. CONCLUSION: The spectral reflectance of craniofacial structures can be measured with acceptable validity and test-retest reliability using a noncontacting 45/0-degree optical configuration.

PMID: 17280891 [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 influence of commercially pure titanium and titanium-aluminum-vanadium alloy on the final shade of low-fusing porcelain.

J Contemp Dent Pract. 2007;8(2):97-104

Authors: Al Wazzan KA, Al Hussaini IS

AIMS: The aims of this study were to investigate the influence of commercially pure titanium (PTi) and titanium-aluminum-vanadium (Ti-6Al-4V) alloys (TiA) on the final shade of low-fusing porcelain bonded to them and to compare the shade changes with those of three conventional metal-ceramic systems. METHODS AND MATERIALS: A titanium casting unit was used to cast PTi and Ti-6Al-4V alloy specimens followed by A3 shade low-fusing porcelain (Noritake) being bonded to them. Gold-based (AuA), palladium-based (PdA), and nickel-chromium (Ni-Cr) alloys were cast with an automatic centrifugal casting machine, then A3 shade conventional porcelain material (Vita, VMK 95) was applied to them. Ten specimens of each metal were then fabricated. The CIE L* a* b* color coordinates of the specimens were measured with a spectrophotometer. RESULTS: All alloys had significant color changes when compared with A3 shade tabs. The color differences from the shade tabs were 5.79 for the Ti-6Al-4V group, 6.46 for PdA alloy, 8.12 for AuA alloy, 8.15 for Ni-Cr alloy, and 12.58 for PTi. The specimens differed from the shade tabs primarily because of the differences in a* and b* coordinate values. CONCLUSIONS: Predictable shade reproduction of metal-ceramic restorations (MCRs) may be impaired by the underlying metal. The PTi had the greatest color differences among all the tested metal when compared with the shade tabs, whereas the Ti-6Al-4V alloy had the lowest. PTi is more likely to affect the final shade of low-fusing porcelain than Ti-6Al-4V alloy.

PMID: 17277832 [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]

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]

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]

Evaluation of the marginal gingival health using laser Doppler flowmetry.

Braz Dent J. 2006;17(3):219-22

Authors: Develioglu H, Kesim B, Tuncel A

The purposes of this study were to compare the gingival blood flow (GBF) in test sites (teeth retaining fixed partial dentures) and control sites (contralateral natural teeth) and investigate whether there is any relationship between clinical indices and GBF values. Twelve healthy subjects (6 females and 6 males) aged 20 to 54 years were enrolled this study. The GBF was measured from the middle point of the marginal gingiva in the test and control sites using laser Doppler flowmetry (LDF). Additionally, plaque index, gingival index and probing depth measurements were recorded. Statistically significant difference (p<0.05) was found between the test and control sites for marginal GBF. In contrast, no significant difference (p>0.05) was found between test and control sites with respect to the clinical indices, except for plaque index. The findings of this study suggest that there is a significant relation between resin-bonded fixed partial dentures with margins located subgingivally and marginal GBF. Clinical indices are helpful to collect information about the clinical health status of gingival tissues, but GBF is a good tool to measure gingival tissue blood flow and assess periodontal health. In conclusion, laser Doppler flowmetry can be used together with clinical indices to evaluate the marginal gingival health.

PMID: 17262128 [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]

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]