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]

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]

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]

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]

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]

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]

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]

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]

Marginal and internal adaptation of commercially pure titanium and titanium-aluminum-vanadium alloy cast restorations.

J Contemp Dent Pract. 2007 Jan 1;8(1):19-26

Authors: Al Wazzan KA, Al-Nazzawi AA

AIM: The purpose of this in vitro study was to investigate the marginal accuracy and internal fit of complete cast crowns and three-unit fixed partial dentures (FPDs) cast with commercially pure titanium (CPTi) and Titanium-Aluminum-Vanadium alloy (Ti-6Al-4V). METHODS AND MATERIALS: CPTi and Ti-6Al-4V alloy were used to cast twelve single crowns and twelve three-unit FPDs. A traveling microscope was used to measure marginal gap and discrepancies in internal fit. Two and one-way analysis of variance (ANOVA) analyses were used to determine the effects of the marginal and internal fit discrepancies. RESULTS: The Ti-6Al-4V alloy demonstrated a significantly smaller marginal gap than CPTi (P<0.0001). The recorded marginal discrepancies for both metals were within a clinically accepted range (<100 microm). The single crown fit discrepancy was significantly smaller than the three-unit FPD for both the CPTi and the Ti-6Al-4V alloy (P<0.0001). For the internal fit discrepancy, the occlusal surface showed the greatest gaps. CONCLUSIONS: The Ti-6Al-4V alloy demonstrated a better fit than CPTi. Single crowns showed an improved fit when compared with the three-unit FPD. Mid-occlusal internal gap demonstrated greater values than the axial internal gap. CLINICAL IMPLICATIONS: This in vitro study suggested marginal fit of complete crowns and three-unit FPDs cast by CPTi or Ti-6Al-4V alloy were within the range of what is clinically acceptable for longevity of restorations.

PMID: 17211501 [PubMed - indexed for MEDLINE]

Eye safety practices in U.S. dental school restorative clinics, 2006.

J Dent Educ. 2006 Dec;70(12):1294-7

Authors: Hill EE

This study was conducted to determine how much progress U.S. dental schools have made in providing eye protection during restorative (adult operative and fixed prosthodontic) procedures since a 1979 survey. A seven-question survey was placed at a website, and fifty-five different U.S. dental schools were asked to complete the survey. Thirty-one schools responded (56 percent). Eighty-four percent of schools had safety glasses available for patients, but only 77 percent required usage during restorative procedures. Similarly, while 87 percent of schools required dental students working in restorative clinics to wear safety glasses, just 73 percent enforced the policy. Additionally, 84 percent provided blue light protection on curing lights and required students to wear eye protection while doing lab procedures. Compared to the 1979 survey, considerable progress has been made over the last twenty-seven years in protecting dental school patients and students from ocular injuries. Because one would hope to have 100 percent compliance on this issue, there is room for improvement in promoting patient eye safety and teaching good habits to dental students.

PMID: 17170319 [PubMed - indexed for MEDLINE]

Radiographic assessment of post-retained crowns in an adult Jordanian population.

J Contemp Dent Pract. 2006 Sep 1;7(4):29-36

Authors: Al-Hamad KQ, Al-Omari M, Al-Wahadni A, Darwazeh A

AIM: The objective of this study was to radiographically assess and compare the quality of post-retained crowns fabricated at the Dental Health Centre of the Jordan University of Science & Technology (JUST). METHODS AND MATERIALS: Study data were collected in 2002 from existing dental records for all patients receiving treatment with post-retained crowns between October, 1997 and June, 1999. The posts were assessed radiographically to evaluate various aspects of the quality of post-retained crowns. All 129 posts were fabricated in the dental school. RESULTS: The most-frequently restored teeth were the maxillary incisors (38.8%). Sixty-two percent of the posts were tapered, while 38% were parallel-sided. The mean length of the posts was 0.95 mm (SD 0.41) with a range between 0.22-2.85 mm. Caries was diagnosed radiographically in 10.8% of cases with lesions located on root surfaces in 64.3% of them, while 35.7% of lesions were within the root canal. Three posts (2.3%) were deviated from the line of the root canal in the mesio-distal plane. No evidence of root filling was found in 2.3% of the cases. In the remainder of teeth 15.5% had gutta percha extended to the radiographic apex of the tooth, while 59.7% fell 0.5-1 mm short of the radiographic apex. Gutta-percha was extruded beyond the apex in 22.5% of the teeth. Space between the end of the post and the root filling was found in 22.2%. The percentage of canals with apparently completely healthy periapical tissue was 51.2%. In the rest of the cases 34.8% had areas of radiolucency at or near the root apices and 14% demonstrated widening of the periodontal space around the root apex. Root resection had been completed in 2.3% cases. Signs of external resorption were apparent in one case (0.78%). CONCLUSION: The standards of the treatment of the endodontically treated teeth made at the dental hospital were satisfactory but could be improved by a controlled academic supervisory environment and a strict scientific approach to fixed prosthodontics within the dental school.

PMID: 16957788 [PubMed - indexed for MEDLINE]

The efficacy of noncontingent escape for decreasing children's disruptive behavior during restorative dental treatment.

J Appl Behav Anal. 2006;39(2):161-71

Authors: O'Callaghan PM, Allen KD, Powell S, Salama F

We evaluated the effectiveness of a dentist-implemented behavioral intervention in which brief escape from dental treatment was provided on a regular basis, independent of the child's behavior. Within a multiple baseline design across subjects, 5 children, ages 4 to 7 years, were provided with temporary escape from dental treatment on a fixed-time schedule. The intervals were signaled by an electronic timer worn by the dentist. Clinically significant reductions were observed in physically disruptive behavior across all 5 children with the introduction of noncontingent escape, and verbally disruptive behavior was markedly reduced in 4 of the 5 children. In addition, the dental staff s use of physical restraint was reduced to near zero across all 5 children. The research extends the literature in both clinical dentistry and in applied behavior analysis by demonstrating that a dentist can easily and effectively implement noncontingent reinforcement to produce clinically significant and socially important changes in children's health behavior.

PMID: 16813038 [PubMed - indexed for MEDLINE]

Has the 'total-etch' concept disappeared?

J Am Dent Assoc. 2006 Jun;137(6):817-20

Authors: Christensen GJ

PMID: 16803812 [PubMed - indexed for MEDLINE]

Two new clinical/laboratory protocols for CAD/CAM implant restorations.

J Am Dent Assoc. 2006 Jun;137(6):794-800

Authors: Drago CJ

BACKGROUND: Conventional casting technology has some disadvantages for dental laboratory technicians and restorative dentists, including porosity of restorations, miscasting and inaccuracy. It also is labor-intensive. Computer-aided design/computer-aided manufacturing (CAD/CAM) technology was developed in the late 1980s for dentistry, and it significantly reduced and/or eliminated problems associated with dental castings. The purpose of this article is to give readers an overview of the use of CAD/CAM technology for dental implants and illustrate two clinical protocols for that use. CLINICAL IMPLICATIONS: The CAD/CAM technology described in this article can reduce restorative dentists' chairside time associated with implant treatment in both edentulous and partially edentulous patients, can decrease costs without sacrificing accuracy or biocompatibility for both clinicians and dental laboratory technicians, and is available to dental laboratories without the capital expenses associated with purchasing new technology.

PMID: 16803809 [PubMed - indexed for MEDLINE]

A retrospective clinical evaluation of two-unit cantilevered resin-bonded fixed partial dentures.

J Am Dent Assoc. 2006 Jun;137(6):783-8

Authors: Botelho MG, Leung KC, Ng H, Chan K

BACKGROUND: The authors conducted a study to examine the clinical performance of two-unit cantilevered resin-bonded fixed partial dentures (RBFPDs) that were inserted at The Prince Philip Dental Hospital, University of Hong Kong. METHODS: The authors recalled patients who had received two-unit cantilevered RBFPDs at least 24 months before the recall examination. The authors recorded the following data: patient's sex and age, operator's experience, prosthesis cementation date, endodontic treatment if performed, bone support, tooth mobility, the presence of shim-stock contacts on the abutment or pontic in intercuspal position, and the presence of aproximal axial contacts adjacent to the prosthesis. They also recorded the date of any debonding with subsequent treatment. They asked the patients qualitative questions about their prostheses. RESULTS: A total of 269 prostheses were placed in 214 patients and had a mean service life of 51.7 months +/- 19.5 months standard deviation, with a range of 13.2 to 141.6 months. Of 14 failed prostheses, 12 debonded, resulting in a success rate of 94.8 percent and clinical retention rate of 95.5 percent. No discernable rotation or drifting of the abutments was apparent in any of the prostheses. Overall patient satisfaction with RBFPDs was good, with an average assessment score of 8.5. CONCLUSIONS: The authors observed a 95.5 percent clinical retention rate of 269 two-unit RBFPDs, with no apparent drifting of the abutments. Longer-term follow-up studies are required. CLINICAL IMPLICATIONS: Two-unit RBFPDs are conservative and clinically retentive prostheses in the short to medium term.

PMID: 16803807 [PubMed - indexed for MEDLINE]

Microhardness of Ni-Cr alloys under different casting conditions.

Braz Oral Res. 2006 Jan-Mar;20(1):40-6

Authors: Bauer JR, Loguercio AD, Reis A, Rodrigues Filho LE

This study evaluated the microhardness of Ni-Cr alloys used in fixed prosthodontics after casting under different conditions. The casting conditions were: (1-flame/air torch) flame made of a gas/oxygen mixture and centrifugal casting machine in a non-controlled casting environment; (2-induction/argon) electromagnetic induction in an environment controlled with argon; (3-induction/vacuum) electromagnetic induction in a vacuum environment; (4-induction/air) electromagnetic induction in a non-controlled casting environment. The 3 alloys used were Ni-Cr-Mo-Ti, Ni-Cr-Mo-Be, and Ni-Cr-Mo-Nb. Four castings with 5 cylindrical, 15 mm-long specimens (diameter: 1.6 mm) in each casting ring were prepared. After casting, the specimens were embedded in resin and polished for Vickers microhardness (VH) measurements in a Shimadzu HMV-2 (1,000 g for 10 s). A total of 5 indentations were done for each ring, one in each specimen. The data was subjected to two-way ANOVA and Tukey's multiple comparison tests (alpha = 0.05). The VH values of Ni-Cr-Mo-Ti (422 +/- 7.8) were statistically higher (p < 0.05) than those of Ni-Cr-Mo-Nb (415 +/- 7.6). The lowest VH values were found for Ni-Cr-Mo-Be (359 +/- 10.7). The VH values obtained in the conditions induction/argon and induction/vacuum were similar (p > 0.05) and lower than the values obtained in the conditions induction/air and flame/air torch (p < 0.05). The VH values in the conditions induction/air and flame/air were similar (p > 0.05). The microhardness of the alloys is influenced by their composition and casting method. The hardness of the Ni-Cr alloys was higher when they were cast with the induction/air and flame/air torch methods.

PMID: 16729173 [PubMed - indexed for MEDLINE]

Do admissions data and NBDE Part I scores predict clinical performance among dental students?

J Dent Educ. 2006 May;70(5):518-24

Authors: Park SE, Susarla SM, Massey W

The purpose of this study was to evaluate possible associations between a variety of measures used to evaluate didactic knowledge and clinical performance within a predoctoral dental program. In this study, clinical performance was assessed by clinical productivity and clinical proficiency across four different competency areas: operative dentistry, major restorative dentistry, fixed prosthodontics, and removable prosthodontics. Predental and preclinical predictors were undergraduate GPAs (overall and science), DAT subtest scores (including the Perceptual Ability Test, PAT), and performance on subtests of Part I of the National Board Dental Examination. The sample consisted of eighty-four students at the Harvard School of Dental Medicine who graduated during the period 2002-04. Associations between predictors and outcomes were first evaluated individually. Any associations that were near statistically significant (p=0.15) were then included in a multiple linear regression model. The criterion for statistical significance in the multiple linear regression model was p=0.05. While a number of measures were associated in bivariate analyses, few predictors were statistically significantly associated with clinical outcomes in the multiple regression analyses. Those predictors that were associated with clinical outcomes were also not consistently associated with the different outcomes studied. These data indicate that, within this study population, there is little to no uniform association between preclinical didactic performance and measurements of clinical productivity and clinical proficiency. It is possible that the overlap in skill sets required for success in the predental/preclinical and clinical areas is minimal.

PMID: 16687636 [PubMed - indexed for MEDLINE]

Fixed space maintainers combined with open-face stainless steel crowns.

J Contemp Dent Pract. 2006 May 1;7(2):95-103

Authors: Yilmaz Y, Kocogullari ME, Belduz N

OBJECTIVE: This study investigates the clinical performance of fixed space maintainers placed on seriously damaged abutment teeth. METHODS: Crowns were placed on damaged abutment primary teeth. Fixed space maintainers were prepared by using rectangular wire between the window in the facial surface of the crowns and other abutment teeth and were subsequently bonded with a flowable resin composite. This procedure was introduced clinically, and the cases were observed over a period of twelve months. RESULTS: Twenty-seven fixed space maintainers (25 on lower jaw, two on upper jaw) were included in this study. No clinical failure was recorded in any of the cases in the observation time, and the rate of clinical performance was 100%. CONCLUSION: The study shows the effectiveness of fixed space maintainers combined with stainless steel crowns ("open-face fixed space maintainers") which were placed on primary molar teeth used as abutments in cases with extensive caries and loss of occlusogingival dimension.

PMID: 16685300 [PubMed - indexed for MEDLINE]

Fracture surface analysis of clinically failed fixed partial dentures.

J Dent Res. 2006 Mar;85(3):277-81

Authors: Taskonak B, Mecholsky JJ, Anusavice KJ

Ceramic systems have limited long-term fracture resistance, especially when they are used in posterior areas or for fixed partial dentures. The objective of this study was to determine the site of crack initiation and the causes of fracture of clinically failed ceramic fixed partial dentures. Six Empress 2 lithia-disilicate (Li(2)O x 2SiO(2))-based veneered bridges and 7 experimental lithia-disilicate-based non-veneered ceramic bridges were retrieved and analyzed. Fractography and fracture mechanics methods were used to estimate the stresses at failure in 6 bridges (50%) whose fracture initiated from the occlusal surface of the connectors. Fracture of 1 non-veneered bridge (8%) initiated within the gingival surface of the connector. Three veneered bridges fractured within the veneer layers. Failure stresses of the all-core fixed partial dentures ranged from 107 to 161 MPa. Failure stresses of the veneered fixed partial dentures ranged from 19 to 68 MPa. We conclude that fracture initiation sites are controlled primarily by contact damage.

PMID: 16498078 [PubMed - indexed for MEDLINE]

An application of a splint purposeful resin-bonded fixed partial denture after orthodontic treatment: a case report.

J Contemp Dent Pract. 2006 Feb 15;7(1):141-9

Authors: Bayda&#x15F; B, Denizoglu S

An adult male patient who had lost his maxillary left central incisor seven years ago in a traffic accident presented with a chief complaint about his unaesthetic appearance associated with the loss of his maxillary left central incisor space, a Class III molar occlusion, and an anterior open bite malocclusion due to tongue-thrust swallowing. Fixed orthodontic treatment was rendered following fan-type expansion of the maxilla. A Maryland bridge as a minimally invasive dentistry approach was used as a retention appliance and the patient's aesthetic appearance was restored.

PMID: 16491157 [PubMed - indexed for MEDLINE]

Making fixed prostheses that are not too high.

J Am Dent Assoc. 2006 Jan;137(1):96-8

Authors: Christensen GJ

It has been observed that a high percentage of multiple crowns or FPDs arrive from laboratories too "high." This article suggests methods to create accurate alginate impressions, opposing casts and IORs. If dentists use these techniques, it is anticipated that fewer FPDs will be too high as dentists attempt to seat them in the mouth.

PMID: 16457005 [PubMed - indexed for MEDLINE]

Characterization of the peri-implant epithelium in hamster palatine mucosa: behavior of Merkel cells and nerve endings.

Biomed Res. 2005 Dec;26(6):257-69

Authors: Suzuki Y, Matsuzaka K, Ishizaki K, Tazaki M, Sato T, Inoue T

The purpose of this study was to investigate the relationship between Merkel cells and nerve elements during tissue regeneration after receiving dental implants. Golden hamsters were divided into 3 groups and titanium alloy implants were fixed in their left-side maxilla through the third palatine rug. Animals were sacrificed at 1, 2, 3, 4, 5, 6, and 7 days after the implantation and tissues were characterized at the immunohistochemical and morphological levels. CK 20 and PGP 9.5 antibodies which react with Merkel cells and nerve fibers were used. Immunohistochemically, no CK 20-positive Merkel cells were seen in the peri-implant epithelium throughout the 7 days. However, starting at day 4, PGP 9.5-positive nerve fibers appeared in the connective tissue, and by day 7, nerve fibers had invaded the more superficial layer of the peri-implant epithelium compared to the mucosa removal control group. At the electron microscopic level, the intercellular spaces of the regenerating epithelium in the mucosa removal control group were small. In contrast, intercellular spaces of the peri-implant epithelium tended to be wide and regenerating nerve fibers invaded those intercellular spaces. In both the mucosa removal control group and the implantation group, the basal lamina and connective tissues regenerated completely. However, clear Merkel cells containing neurosecretory granules were not observed. Taken together, our results indicate that Merkel cells in the hamster palatine mucosa do not regenerate in the peri-implant epithelium. However, regenerative nerve fibers seem to play essential roles as part of the defense and sensory systems around the peri-implant epithelium to compensate for the weakened defense mechanism.

PMID: 16415507 [PubMed - indexed for MEDLINE]

A single-retainer zirconium dioxide ceramic resin-bonded fixed partial denture for single tooth replacement: a clinical report.

J Oral Sci. 2005 Sep;47(3):139-42

Authors: Komine F, Tomic M

This clinical report describes a treatment for the replacement of a missing mandibular anterior tooth using a cantilever single-retainer resin-bonded fixed partial denture (RBFPD), fabricated from zirconium dioxide (ZrO2) ceramic. No clinical complications were observed at the 2-year 6-month follow-up examination after placement of the ZrO2 ceramic RBFPD, and satisfactory functional and esthetic results were achieved. A treatment modality using a cantilever ZrO2 ceramic RBFPD is an alternative for single anterior tooth replacement. Further clinical studies are required to evaluate the long-term potential of cantilever single-retainer ZrO2 ceramic RBFPDs.

PMID: 16313092 [PubMed - indexed for MEDLINE]

Quantitative evaluation of axial wall taper in prepared artificial teeth.

J Oral Sci. 2005 Sep;47(3):129-33

Authors: Okuyama Y, Kasahara S, Kimura K

The purpose of this study was to quantitatively evaluate the axial wall taper of prepared artificial teeth using a non-contact three-dimensional shape measuring system. A total of 54 artificial teeth prepared by pre-clinical dental students for complete cast restorations were evaluated. For quantitative analysis, five cross sections were computer-graphically placed perpendicularly to the z-axis. The surface coordinate values (x, y, z) of each cross section were converted into polar coordinate values (r, theta), which were then graphically rendered to a two-dimensional plane. At four points, each 90 degrees from the distal center point of the cross section, the axial wall taper was quantitatively calculated using a formula based on the differences in radius between the highest and lowest positions of the cross sections of the prepared tooth. The average calculated taper was 5.8 degrees in the distal region, 21.7 degrees in the buccal region, 14.9 degrees in the mesial region and 12.5 degrees in the lingual region. These results suggest that the axial wall taper of prepared teeth can be quantitatively evaluated using this measuring system.

PMID: 16313090 [PubMed - indexed for MEDLINE]

Fiber-reinforced composite fixed partial denture to restore missing posterior teeth: a case report.

J Contemp Dent Pract. 2005 Nov 15;6(4):168-77

Authors: Rappelli G, Coccia E

In patients refusing implant surgery for psychological reasons, when minimal tooth reduction is desired, a fiber-reinforced composite inlay fixed partial denture (IFPD) can be used to replace missing teeth. In comparison to other restorative systems this conservative approach carries a lower risk of pulp exposure and/or periodontal inflammation, maintaining the health of supporting tissues. The purpose of this case report is to describe the clinical procedure for fabricating an IFPD with a pre-impregnated glass fiber system and a hybrid composite. Fiber-reinforced composite, in combination with adhesive techniques, appears promising for an IFPD. Further clinical investigation will be required to provide additional information on this technique.

PMID: 16299619 [PubMed - indexed for MEDLINE]

Failures related to crowns and fixed partial dentures fabricated in a Nigerian dental school.

J Contemp Dent Pract. 2005 Nov 15;6(4):136-43

Authors: Oginni AO

The purpose of this investigation was to document the failure rate and length of service of crowns and fixed partial dentures (FPDs) fabricated in a Nigerian dental school. The reasons for failure of the initial restorations and their length of service were also ascertained. Also, the numbers of retainers, pontics, and the types of restoration were recorded. Poor esthetics was the most frequent cause of failure, 66 units (40.5%); followed by fracture, 58 units (35.6%); and dental caries, 25 units (15.4%). These outcomes were contrary to findings previously reported in studies from western countries where dental caries was principally responsible for failures (22.0% to 38.0% of cases). The resin-retained FPDs had the shortest mean years of service at 2.7 years, while the three-unit metal-ceramic FPDs had the greatest longevity at 8.6 years. The overall mean years of service for replaced restorations were 5.6 years. The study found a decrease in the mean years of service as the number of units in the fixed-fixed partial dentures increased. This is in sharp contrast to previous reports where no relationship existed between length of service and the number of units in a FPD.

PMID: 16299615 [PubMed - indexed for MEDLINE]

'A simpler technique'.

J Am Dent Assoc. 2005 Sep;136(9):1218

Authors: Guinta JL

PMID: 16196227 [PubMed - indexed for MEDLINE]

Microbial leakage of Cavit, IRM, and Temp Bond in post-prepared root canals using two methods of gutta-percha removal: an in vitro study.

J Contemp Dent Pract. 2005 Aug 15;6(3):53-61

Authors: Balto H, Al-Nazhan S, Al-Mansour K, Al-Otaibi M, Siddiqu Y

The aim of this study was to evaluate the integrity of the coronal seal of Temp-Bond and compare it to Cavit and IRM after post space preparation using S. faecalis as a microbial tracer. In addition, the affect of two methods of gutta percha removal on the apical seal of root canal fillings was also evaluated. Forty extracted human single rooted teeth were prepared chemomechanically and obturated with gutta percha and AH26 sealer cement using the lateral cold condensation technique to a standardized working length of 15 mm. About 10 mm of the coronal gutta-percha was removed with either Peeso-reamer or a hot plugger. The roots were divided into three experimental groups of 10 roots and a control group. Each experimental group was subdivided equally into two groups of 15 each according to the method of post space preparation. Cavit, IRM, and Temp-Bond were used to seal the access opening. Each root was fixed in a cuvette containing Tryptic Soya Broth which, covered 2 mm of the root apex. Bacterial suspension was introduced through pipette. Fresh bacterial suspension was added every week, and the system was monitored daily for the growth of microorganisms for a period of one month. The results showed there was no significant difference in terms of coronal leakage between the three coronal materials used (P=0.478), but the methods of gutta-percha removal did have an impact on the apical leakage (P=0.047). The mean value showed the Peeso-reamer provided less leakage compared to using a hot plugger during the 30-day experimental time period. It was concluded the temporary type of coronal seal of endodontically treated teeth will not prevent coronal leakage if left for a long period of time. In addition, permanent cementation of the post with the coronal restoration should be carried out as soon as possible to prevent recontamination of the root canal.

PMID: 16127472 [PubMed - indexed for MEDLINE]

Making fixed provisional restorations for patients hypersensitive to acrylic resin.

J Am Dent Assoc. 2005 Jun;136(6):779-80

Authors: Cohen MD

PMID: 16022043 [PubMed - indexed for MEDLINE]

Effect of noble metal adhesive systems on bonding between an indirect composite material and a gold alloy.

J Oral Sci. 2004 Dec;46(4):235-9

Authors: Nagano K, Tanoue N, Atsuta M, Koizumi H, Matsumura H

In this study, the bond strength between an indirect composite and a gold alloy was determined for the purpose of evaluating noble metal bonding systems. A single liquid primer designed for conditioning noble metal alloys (Infis Opaque Primer) and tri-n-butylborane-initiated adhesive resins (Super-Bond C & B), with or without the powder component, were assessed. Cast gold alloy disks (Casting Gold type IV) were air-abraded with alumina, followed by six surface preparations, and were then bonded with a light-activated composite material (New Metacolor Infis). Shear testing was performed both before and after thermocycling for evaluation of bond durability. The results showed that three primed groups improved post-thermocycling bond strengths compared to each of the corresponding unprimed groups (P < 0.01). The bond strength was reduced for all six groups by the application of thermocycling (P < 0.01). After thermocycling, the group primed with the Infis Opaque Primer material and bonded with the Super-Bond C & B resin exhibited the greatest bond strength (23.4 MPa). The Infis Opaque Primer and Super-Bond bonding system increased the post-thermocycling bond strength of the control group by a factor of approximately ten. This simple technique is applicable in the fabrication of composite veneered restorations and cone-telescope dentures.

PMID: 15901068 [PubMed - indexed for MEDLINE]

[Application of Bränemark system's multi-unit abutment: report of 37 consecutive cases]

Shanghai Kou Qiang Yi Xue. 2005 Apr;14(2):120-2

Authors: Yu YC, Gu ZY, Wang Q, Gong YM, Bi W, Ruan H

PURPOSE: To evaluate the short-term clinical effect and advantages of Bränemark system's multi-unit abutment used for standard or MK III implants supported fixed prosthodontics. METHODS: Routine clinical examinations and preparations, including panoramic tomography, periapical radiograph and surgical guide plate, were performed in 37 cases with multiple lost teeth. A total of 117 Bränemark system's implants were placed using a two-stage surgical approach. Multi-unit abutment connection was performed 3-6 months after implant installation. All superstructure prosthetic appliances were porcelain-fused-to-golden metal bridges. RESULTS: The follow-up period for the implants was 12 to 24 months. The total survival rate was 95.7%. Two implants were lost at second-stage surgery (the survival rate was 98.29% for first-stage), and 3 implants were lost after loading (the survival rate was 97.43% for second-stage). The other 112 implants function uneventfully. There were no bone loss around implants, no abutment and gold cylinder screw loosen. CONCLUSIONS: The multi-unit abutment, on basis of collecting all the merits of the traditional abutment, was further designed in a simplified way, which not only expands its clinical application, operate easily, but also enhance its whole superstructure. It is more suitable for implant supported fixed prosthodontics with high success rate and more advantages than the traditional abutment.

PMID: 15886831 [PubMed - in process]

The state of fixed prosthodontic impressions: room for improvement.

J Am Dent Assoc. 2005 Mar;136(3):343-6

Authors: Christensen GJ

Impressions for crowns and fixed prostheses could be better. I have offered several suggestions to improve their quality. None of the suggestions is difficult or time-consuming. The result of making better impressions will be greater longevity for the resultant restorations and happier patients, dentists and laboratory technicians.

PMID: 15819348 [PubMed - indexed for MEDLINE]

Fixed prosthetics with a connective tissue and alloplastic bone graft ridge augmentation: a case report.

J Contemp Dent Pract. 2004 Nov 15;5(4):111-21

Authors: Breault LG, Lee SY, Mitchell NE

Augmentation of the partially edentulous ridge can significantly improve the final prosthodontic rehabilitation. For enhancing soft tissue contours in the anterior region, the subepithelial connective tissue graft is the treatment of choice. The combination of connective tissue grafts with alloplastic bone graft material can optimize the ridge augmentation and reduce post extraction defects. The aim of this clinical report is to describe the use of subepithelial connective tissue in conjunction with an alloplastic bone graft for augmentation of a maxillary anterior ridge prior to prosthetic rehabilitation.

PMID: 15558096 [PubMed - indexed for MEDLINE]

Influence of Different Techniques of Laboratory Construction on the Fracture Resistance of Fiber-Reinforced Composite (FRC) Bridges.

J Contemp Dent Pract. 2004 Nov 15;5(4):1-13

Authors: Ellakwa AE, Shortall AC, Marquis PM

The aim of the current investigation is to evaluate optimal pontic and retainer fiber positions for Polyethylene fiber-reinforced composite (FRC) restorations. In series I notch disc specimens were used to mimic loading cuspal regions of pontics. Four groups (n=15/group; codes A to D) were prepared from Artglass composite. Groups A to C were reinforced with polyethylene fibers, and group D was an unreinforced control. Fibers were positioned either around (A), beneath the notch (B), or at the disc base (C). Specimens were stored in distilled water at 37 degrees C for 24 h before testing to failure (CHS=1mm/min) in a universal testing machine. Mean torque to failure values ranked [P< 0.05; one-way analysis of variance (ANOVA)] as follows A = B > C = D. In series II five groups of three unit bridges (n =5/group; codes A to E) were prepared from Artglass dental composite without (group A) or with (groups B to E) different Connect fiber reinforcement locations/techniques. Bridges were cemented using 2 bond resin cement to a standardized substructure. After storage, as per series I, bridges were loaded mid-pontic region to failure. One-way ANOVA showed no significant (P=0.08) difference between test groups. The research hypothesis was that notched disc and 3 unit bridge test techniques would discriminate equally between fiber-reinforced specimens and an unreinforced composite control was rejected.

PMID: 15558085 [PubMed - indexed for MEDLINE]

Aspiration and ingestion in dental practice: a 10-year institutional review.

J Am Dent Assoc. 2004 Sep;135(9):1287-91

Authors: Tiwana KK, Morton T, Tiwana PS

BACKGROUND: This article is an institutional retrospective review of incidents involving aspiration and ingestion of dental foreign objects at a large multidisciplinary dental educational facility. It was undertaken to determine which dental procedures were more likely to involve aspiration or ingestion, as well as to evaluate the outcome of these adverse incidents. METHODS: The inclusion criteria involved all patients who were documented to have experienced loss of dental instruments or material behind the posterior pharynx during a 10-year consecutive period. The dental and medical records of these patients were analyzed, and the outcomes of the adverse events fell into three categories: aspiration, ingestion, or neither aspirated nor ingested. The authors also noted the type of dental instrument and the specialty or area of dentistry in which this event occurred. RESULTS: There were 36 documented cases. Twenty-five of these were instances of ingestion and one was an aspiration. In 10 cases, aspiration and ingestion were ruled out through radiographic examination or the object was retrieved from the patient's mouth. CONCLUSIONS: Fixed prosthodontic therapy had the highest number of incidents of adverse outcomes. Ingestion was a more prevalent outcome than aspiration. Dental procedures involving single-tooth cast or prefabricated restorations involving cementation have a higher likelihood of aspiration. CLINICAL IMPLICATIONS: The implications for clinical practice include the recognition of risk that dental therapy demands in regard to the airway and posterior pharynx, documentation and follow-up of adverse outcomes, and the use of preventive measures such as rubber dams or gauze throat screens or floss ligatures.

PMID: 15493393 [PubMed - indexed for MEDLINE]

Interdisciplinary management of dental implant patient: a case report.

Kaohsiung J Med Sci. 2004 Aug;20(8):415-8

Authors: Chen CM, Tseng YC, Huang IY, Yang CF, Shen YS, Lee HE, Chen CH

Maxillary molars can over-erupt when their antagonists are lost and there are no replacements. When the opposing molars severely extrude into the edentulous space, it is difficult to replace the missing teeth with either fixed or removable prostheses. We present the following case report, providing a solution for this type of problem. A two-stage posterior subapical osteotomy was used to reestablish the intermaxillary space. Following orthodontic treatment and implant placement, the patient regained occlusal harmony and normal masticatory function.

PMID: 15473654 [PubMed - indexed for MEDLINE]

Changes in occlusion and maxillary dental arch dimensions in adults with treated unilateral complete cleft lip and palate: a follow-up study.

Eur J Orthod. 2004 Aug;26(4):385-90

Authors: Marcusson A, Paulin G

The purpose of this study was to evaluate the occlusion and maxillary dental arch dimensions in adults with repaired complete unilateral cleft lip and palate (UCLP) and to investigate the patterns of change in early adulthood. Study models from 39 patients (25 men, 14 women; mean age 24.7 years, range 20.2-29.3 years) with a diagnosis of complete UCLP taken at a follow-up examination were analysed and compared with the study models taken at baseline examination (mean age 19.1 years, range 16.0-20.6 years). Lip closure was carried out according to the Millard technique and palatal closure according to the Wardill-Kilner technique. All patients had received orthodontic treatment with fixed appliances. The patients were divided into three groups according to the type of retention in the upper arch: no retention (n = 15), retention with a bonded twisted retainer (n = 13), an onlay or fixed bridge (n = 11). Occlusion was evaluated according to a scoring system. The maxillary dental arch dimensions were measured with a video imaging system. There was a significant deterioration in the total occlusal score during the follow-up period and this was larger on the cleft than on the non-cleft side. There were no significant differences in the anterior scores. A comparison of the transversal and sagittal maxillary arch dimensions revealed significant differences in all measurements during the follow-up interval. The reduction was largest for the maxillary second premolar width, followed by the first molar width. The overjet differed significantly between the registrations. The occlusal score and the maxillary arch dimensions were reduced in all of the three subgroups, but there were no differences between the groups.

PMID: 15366382 [PubMed - indexed for MEDLINE]

[Advances in the research of all-ceramic FPD]

Shanghai Kou Qiang Yi Xue. 2004 Aug;13(4):321-4

Authors: Zhang LP, Mou YZ

The all-ceramic restoration has no metal base,no need to mask, and it also has perfect esthetic attribute. But in the past, lower strength restricted its clinical use. With the development of high strength ceramics, all-ceramic restoration has been widely used than before. Recently, more and more research on all-ceramic materials, laboratory test and clinical test showed good prospect in prosthodontics field.

PMID: 15349678 [PubMed - indexed for MEDLINE]

Implantology and the severely resorbed edentulous mandible.

Crit Rev Oral Biol Med. 2004;15(4):240-8

Authors: Stellingsma C, Vissink A, Meijer HJ, Kuiper C, Raghoebar GM

Patients with a severely resorbed edentulous mandible often suffer from problems with the lower denture. These problems include: insufficient retention of the lower denture, intolerance to loading by the mucosa, pain, difficulties with eating and speech, loss of soft-tissue support, and altered facial appearance. These problems are a challenge for the prosthodontist and surgeon. Dental implants have been shown to provide a reliable basis for fixed and removable prostheses. This has resulted in a drastic change in the treatment concepts for management of the severely resorbed edentulous mandible. Reconstructive, pre-prosthetic surgery has changed from surgery aimed to provide a sufficient osseous and mucosal support for a conventional denture into surgery aimed to provide a sufficient bone volume enabling implants to be placed at the most optimal positions from a prosthetic point of view. The aim of this paper is to review critically the literature on procedures related to the severely resorbed edentulous mandible and dental implant treatment. The study includes the transmandibular implant, (short) endosseous implants, and reconstructive procedures such as distraction osteogenesis, augmentation of the mandibular ridge with autogenous bone, and bone substitutes followed by the placement of implants. The number of patients participating in a study, the follow-up period, the design of the study, the degree of mandibular resorption, and the survival rate of the dental implants all are considered evaluation parameters. Although numerous studies have described the outcome results of dental implants in the edentulous mandible, there have been few prospective studies designed as randomized clinical trials that compare different treatment modalities to restore the severely resorbed mandible. Therefore, it is not yet possible to select an evidence-based treatment modality. Future research has to be focused on long-term, detailed follow-up clinical trials before scientifically based decisions in treating these patients can be made. This will contribute to a higher level of care in this field.

PMID: 15284188 [PubMed - indexed for MEDLINE]

Is occlusion becoming more confusing? A plea for simplicity.

J Am Dent Assoc. 2004 Jun;135(6):767-8, 770

Authors: Christensen GJ

It is not difficult to observe and record patient occlusal characteristics before starting simple or complex occlusal rehabilitations. If this is done, and if the subsequently placed crowns and fixed prostheses are constructed in observation of similar characteristics, clinical success usually is the result. Deviations from the suggestion to duplicate the "normal" occlusion should be made when the original natural occlusion had caused overt pathosis, or when all teeth or one arch of the teeth is being restored at one time. If this is the case, centric relation occlusion is more reproducible and easier to develop than occlusion with a shift from centric relation to centric occlusion. Peculiar requests of patients relative to occlusal positioning, or routine dependence on various devices to predetermine occlusal characteristics for rehabilitation (as is currently popular in some groups), should be considered, but they should be tempered with careful observation of preoperative occlusal characteristics.

PMID: 15270161 [PubMed - indexed for MEDLINE]

[The establishment of 3D-FE model libraries for the elements of FPD]

Shanghai Kou Qiang Yi Xue. 2004 Apr;13(2):115-7

Authors: Zheng YL, Wei B, Zhang FQ, Yu LN, Wang CT

PURPOSE: To establish the 3D-FE model libraries for the elements of the FPD. METHODS: Based on the 3-D geometric model libraries of the normal stomatognathic system, using the software, such as Powershape,Pro/E and Ansys5.5, the models of abutments,retainers and pontics were created according to the models of natural crowns. The models of connectors were established according to the sutures between the crowns. RESULTS: This study has established the FE model libraries for the elements of the FPD, including the retainers,pontics,and connectors, three kinds of libraries and 82 elements in all. CONCLUSION: The established models have a satisfied geometric configuration; the analysis models can be easily established and edited.

PMID: 15133554 [PubMed - indexed for MEDLINE]

AIDA: web agents in dental treatment planning.

Adv Dent Res. 2003 Dec;17:74-6

Authors: Finkeissen E, Stamm I, M&#xFC;ssig M, Streicher J, Koke U, Helmstetter C, Hassfeld S, Wetter T

The objective of the AIDA project (Artificial Intelligent Dental Agents, http://aida.uni-hd.de) is the analysis of dental decision-making, the design of a computer-based decision support system, as well as the testing of the decision structure in interactions with dental experts, practicing dentists, and patients. The planning of the solution alternatives for an individual patient is based on a top-down structure for dental decision-making, aiming at a standardization of the argumentation. From a theoretical point of view, decision support can be provided only for anticipated decisions (planning). Moreover, only parts of these anticipated decisions can be supported. Accordingly, a separation of these partial aspects has to take place before one is able to build decision support systems. For prosthetic dentistry, clinicians have been shown how to use individual patient findings to sketch the possible treatment alternatives and later derive guidelines for the treatment. The planning module for fixed prostheses has already been integrated into a software agent. Planning modules for other types of prostheses are currently specified, implemented, and verified.

PMID: 15126212 [PubMed - indexed for MEDLINE]

Improving quality and speed in providing fixed prosthodontics.

J Am Dent Assoc. 2004 Mar;135(3):333-5

Authors: Christensen GJ

American dentists should be pleased with the level of care they provide to their patients in the area of fixed prosthodontics. The American public is served with good, competent care at a moderate cost. However, this article has addressed the potential for increasing the quality level of care, increasing the speed of treatment and maintaining the moderate cost by delegating some of the clinical tasks to qualified staff members. In my opinion and experience, these results are achievable by delegating up to one-half of the time involved in fixed prosthodontic clinical tasks to qualified, educated, supervised non-dentist staff members, where such delegation is legal.

PMID: 15058622 [PubMed - indexed for MEDLINE]

Speech with maxillary implant prostheses: ratings of articulation.

J Dent Res. 2004 Mar;83(3):236-40

Authors: Heydecke G, McFarland DH, Feine JS, Lund JP

Speech is often perturbed after placement of maxillary implant-retained prostheses. We tested the hypothesis that the rate of speech errors varies with prosthetic design. Thirty edentulous subjects with mandibular implant prostheses entered two within-subject crossover trials. Subjects wore maxillary fixed prostheses and removable long-bar overdentures (Trial 1), or overdentures with and without palates (Trial 2). Test words from a French language speech battery were recorded after each prosthesis had been worn for two months. The percentages of stops, fricatives, and vowels correctly perceived by lay judges were calculated. Subjects produced a significantly higher percentage of sounds correctly with overdentures than with fixed prostheses. Between-treatment differences were significant for stops and fricatives (p < 0.01), but not for vowels. There were no significant differences in error rates between the two overdentures. In conclusion, maxillary implant overdentures with and without palates enable patients to produce more intelligible speech than fixed prostheses.

PMID: 14981126 [PubMed - indexed for MEDLINE]

[Cell behavior of periodontal ligament cells cultured on commercially pure titanium]

Shanghai Kou Qiang Yi Xue. 2003 Dec;12(6):439-42

Authors: Zhou B, Cheng XR, Jiang T, Wang YN

OBJECTIVE: To study the cell behavior of periodontal ligament cells (PDLCs) cultured on commercially pure titanium (cpTi) by cell morphology, cell counting and osteoclin (OC) immunofluorescent staining. METHODS: 1 x 10(5)/ml PDLCs in 2 ml culture medium were seeded on cpTi discs fixed in 24-well culture plates. Morphological study of cell attachment was observed by scanning electron microscope (SEM) and fluorescence microscopy. Cell adhesion was analyzed by MTT at 0.5, 1, 2, 4 hours respectively. OC was directly observed by immunofluorescent staining. RESULTS: PDLCs could attach and spread on cpTi discs. SEM showed that PDLCs had pseudopod-like protuberance. PDLCs showed different attaching phase and reached saturation in cell number at the early stage. The cells and ECM could express OC 7 days later. CONCLUSION: PDLCs show a regular, dynamic pattern in early stage and they can keep proliferating and differentiating on CpTi in vitro. It was indicated that the biological function of PDLCs around dental implant should be reconsidered.

PMID: 14966586 [PubMed - indexed for MEDLINE]

The confusing array of tooth-colored crowns.

J Am Dent Assoc. 2003 Sep;134(9):1253-5

Authors: Christensen GJ

The venerable PFM crown or fixed prosthesis still dominates the tooth-colored restoration market. However, use of PFMs is declining slightly, as the many new all-ceramic and resin-based composite crowns and fixed-prosthesis products flood the market. Several situations may indicate the use of materials other than PFM. They include patients requiring a high level of esthetic acceptability, patients with proven or perceived allergies to the metals used in dentistry and bruxing or clenching patients with metal allergies or desire to eliminate metal from their mouths. PFM restorations have been proven during 40 years of successful use. They provide acceptable esthetics for most situations, minimal fracture during service, proven ability to serve in multiple-unit situations and excellent fit, and the profession has detailed knowledge of these restorations' advantages, disadvantages and physical characteristics. PFM restorations have only a few well-known negative characteristics. Be cautious as you elect to move from the reliability and positive history of PFM to relatively unknown types of restorations.

PMID: 14528998 [PubMed - indexed for MEDLINE]

Have fixed-prosthodontic impressions become easier?

J Am Dent Assoc. 2003 Aug;134(8):1121-3

Authors: Christensen GJ

Excellent fixed-prosthodontic impressions are ensured with the presence of healthy soft tissue, atraumatic tooth and soft-tissue preparation, use of packing cords when indicated, routine use of astringents and taking enough time to accomplish the preimpression procedures thoroughly. Currently advertised products that supposedly eliminate the difficulty of fixed-prosthodontic impressions and the need for cords have decreased some of the frustrations of impression making, but the challenge remains. Excellent impressions require accurate and stable impression materials, time, conscientious and thorough techniques, attention to every detail, good support staff and a working knowledge of all aspects of the concepts involved.

PMID: 12956356 [PubMed - indexed for MEDLINE]

Repairing fractured porcelain-fused-to-metal bridge pontics.

J Am Dent Assoc. 2003 Aug;134(8):1097-100

Authors: Quarnstrom FC, Aw TC

PMID: 12956351 [PubMed - indexed for MEDLINE]

Implants in handicapped patients.

Med Oral. 2003 Aug-Oct;8(4):288-93

Authors: L&#xF3;pez-Jiménez J, Romero-Domínguez A, Giménez-Prats MJ

Implantology as an approach for replacing missing teeth has become a generalized practice in recent years. The present study describes the results of placing 67 implants in 18 patients with various degrees of mental and physical impediments. Only four implants were lost, though in all cases fixed-prosthesis oral rehabilitation was achieved -- the implant failure rate (5.6%) being similar to that observed in healthy individuals. A description is provided of the course of different clinical cases illustrating the rehabilitation process, from implant placement to completion of the prosthesis. In our opinion, implantology may constitute a valid management alternative to be taken into consideration in the oral rehabilitation of handicapped patients. The use of implants should be evaluated taking into account the particular characteristics of each individual patient.

PMID: 12937390 [PubMed - indexed for MEDLINE]