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Objective: To investigate the effect of the accelerated aging process on the color stability of feldspathic ceramic treated with dual ion exchange, overglaze, polishing, and autoglaze surface treatments. Method and Materials: A total of 40 disks (15 mm in diameter and 2 mm thick) of feldspathic ceramic were made in an A2 shade according to the manufacturer's recommendations. The samples were randomly divided into 4 groups: dual ion exchange, overglaze, polishing, and autoglaze. The samples were subjected to conditions in an accelerated aging machine for 150 and 300 hours. Differences in color before and after accelerated aging were calculated using spectrophotometric analyses. Overall color difference (DE) was determined using the CIE L*a*b* system for measuring small color differences. Scanning electron microscopy was used to evaluate the surface texture of samples. Color difference data were evaluated statistically by Kruskal-Wallis and Mann-Whitney U tests, with a significance level of .05. Results: After 150 and 300 hours of accelerated aging, color changes of the 4 surface treatment groups ranged between 0.35 and 1.31 DE units. All DE values were below a quantitative level that would be considered clinically acceptable. Autoglazed samples were the most color stable, followed by ion exchanged, overglazed, and polished test samples. Conclusions: All groups demonstrated color stability below a quantitative level that would be considered clinically acceptable, but long-term clinical studies are necessary to verify these findings. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effect of oral moisturizing agents, denture adhesives, and surface treatments on the retention of an acrylic resin test base dislodged from the maxillary alveolar ridges of xerostomic radiotherapy patients. Acrylic resin test bases prepared for 10 edentulous xerostomia patients were subjected to 8 surface treatment methods: method 1 = untreated dry surface; method 2 = use of Biotène oral moisturizer; method 3 = use of Protefix denture adhesive; method 4 = combination of Biotène and Protefix; method 5 = sandblasting of test bases; method 6 = use of Biotène on sandblasted surface; method 7 = use of Protefix on sandblasted surface; method 8 = combination of Protefix and Biotène on sandblasted surface. After each treatment, a tensile testing apparatus was used to dislodge the inserted test bases, and force values (N) were recorded. A significant difference in retentive force was observed between the 4 Protefix groups and those that did not use denture adhesive (P < .001). There were no differences among the 4 combinations of denture adhesive treatments (P > .05). Sandblasting the denture surfaces did not increase retentive forces alone or in combination with any other treatments. Biotène oral moisturizing agent was used in 4 treatment methods, but only had a significant effect on increasing retentive force when used with a nonsandblasted surface (P < .05). Biotène had no effect on retentive force compared to a nonsandblasted surface without moisturizer or when it was used in combination with any other methods. Protefix denture adhesive offered the greatest improvement in retentive force. Sandblasting the intaglio surface did not improve retentive force. Biotène was reported to improve patient comfort but had minimal effect on retentive force; however, Biotène can be assumed to be a more advantageous method of increasing retention compared to sandblasting (P < .05). [ABSTRACT FROM AUTHOR]

This study aimed to compare the effect of precementation desensitizing laser treatment and conventional desensitizing agents on crown retention. Crowns were fabricated for 50 molar teeth, and specimens were assigned to 5 groups based on treatment method: untreated control group (CON), laser group (LAS), sodium fluoride group (FLU), Oxagel oxalate group (OXA), and Gluma primer group (GLU). All crowns were luted with glass-ionomer cement. Tensile force was applied for crown dislodgement. Recorded forces and calculated retentive strengths were as follows: CON (261 N) > LAS (223 N) = FLU (208 N) > GLU (161 N) = OXA (147 N) (P < .05). The differences in force magnitudes between all groups were significant (P < .05), except for LAS versus FLU and GLU versus OXA. The retention decrease was 15% for LAS, 20% for FLU, 38% for GLU, and 44% for OXA. Laser treatment had a less negative effect on retention for crowns luted with glass-ionomer cement than the other treatment modalities, and it may be a more suitable desensitization method if crown retention can be moderately sacrificed. [ABSTRACT FROM AUTHOR]

A self-inflicted gunshot maxillofacial defect was restored with dental implants and various attachments. Following mandibular surgical reconstruction, a fixed full-arch implant-supported prosthesis was fabricated. The maxillary defect was restored with an obturator retained with bar-clip and ball attachments. Crowns with an unfavorable crown-to-root ratio were used to rectify a compromised unilateral interocclusal space. Functional rehabilitation was achieved without any pathologic sequelae and maintained over a 1-year observation period. Provision of a fixed implant-retained mandibular prosthesis opposing a specific design for a maxillary obturator provided short-term and optimistic prognosis in the management of a serious traumatic injury. [ABSTRACT FROM AUTHOR]

PURPOSE: To determine the optimal thickness of protective oral radiation shields composed of an acrylic resin stent and a lead shield, which are used in head and neck radiotherapy to minimize undesired normal tissue radiomorbidity. MATERIALS AND METHODS: Intraoral acrylic resin stents and lead shields of different thicknesses were inserted into a specially designed human mandible phantom with thermoluminescent lithium fluoride dosimeter chips (TLD-100) placed on the buccal and lingual sites and exposed to irradiation of different energies. Fifty-cGy irradiation was performed and TLD-100 dose measurements were obtained for each irradiation type, acrylic resin stent thickness, and lead shield thickness. RESULTS: Acrylic resin stents with a 2-mm lead shield reduced 20% and 15% of the normal tissue dose for Co-60 and 6 MV X photon radiations, respectively, whereas the stents with a 4-mm lead shield achieved a higher reduction of the normal tissue dose (30% and 23% for Co-60 and 6 MV X photons, respectively). CONCLUSION: In protective oral radiation shields, acrylic resin stent thickness has little effect on the reduction of normal tissue dose, but lead shield thickness significantly effects the reduction of normal tissue dose. [ABSTRACT FROM AUTHOR]

PURPOSE: The purpose of this in vitro study was to demonstrate the dentinal tubule-occluding effect of desensitizing laser treatment on dentin surfaces using environmental scanning electron microscopy (E-SEM). MATERIALS AND METHODS: Ground dentin surfaces were divided into 5 areas. Each area received a different mode of laser irradiation (low potency [LP] versus high potency [HP] and short time [ST] versus long time [LT]). Lased dentin surfaces were viewed and graded under E-SEM at x5000 magnification. RESULTS: The tubule closure rates of 4 different irradiation modes were as follows: LP/LT (74%) > HP/ST (70%) > LP/ST (51%) > HP/LT (46%) > control (6%). CONCLUSION: It was demonstrated that desensitizing laser application was an efficient treatment option for the occlusion of dentinal tubule apertures. [ABSTRACT FROM AUTHOR]

Objectives: In this study, quantification of backscatter doses between scattering titanium dental implant and the thermoluminescent dosimeter (TLD100) radiation detector at axial beam irradiation-angle range of 0–90° in head and neck radiotherapy is done to evaluate irradiation angle dependency of dose enhancement contributing to osteoradionecrosis. Methods: A cylindrical titanium dental implant with diameter of 4 mm and length of 9 mm was implanted into a specially-designed human mandible phantom with a TLD100 chip placed on the buccal site and irradiated with 6 MV X, 25 MV X and Co-60 gamma sources at 19 different irradiation angles. Results: Dose enhancement on a buccal site of the titanium implant depends on the incident beam angle. At angles of 65°, 60° and 40° the maximum detected scatter doses over the titanium implant are 36%, 32% and 23% for Co-60 gamma, 6 MV X-ray and 25 MV X-ray, respectively. The dose enhancement at different beam angles was less pronounced in 25 MV X and more pronounced in Co-60 gamma irradiation. Conclusions: For the different radiation beams studied, the irradiation angle between scattering titanium dental implants and the central axis does not significantly affect the total dose that may lead to osteoradionecrosis of the mandible. [ABSTRACT FROM AUTHOR]

Little information is available on the immunological basis for side-effects of dental materials. The objective of this study is to evaluate effects of pure metals, dental alloys and ceramic on cell viability and interleukin-1 beta (IL-1 β) release in three-dimensional human gingival fibroblast cultures as an indicator of their biological performance in gingival tissues. The gingival fibroblast cultures were exposed to test specimens fabricated from nickel, iron, molybdenum, copper, indium, gold, Ni–Cr–Mo alloy (Remanium CS), Au–Pt–In alloy (Pontostar) and a dental ceramic (In-ceram). Cell viability was determined by the MTT method 24 and 48 h after exposure. Assays for IL-1 β were carried out by ELISA. Statistical analysis was performed applying the non-parametric Mann–Whitney pairwise test. Dental ceramic and gold did not influence cell viability after 24 and 48 h. Cell viability was determined after 24 and 48 h to nickel (79–77%), iron (92–90%), molybdenum (86–83%), copper (48–36%), indium (90–90%), Remanium CS (83–80%), Pontostar (94–91%) compared with control cultures. Dental ceramic, Pontostar and gold had no significant influence on IL-1 β secretion. The highest amounts of IL-1 β (10-fold) levels were determined in cell cultures exposed to copper. Indium, molybdenum and iron induced twofold IL-1 β levels compared with untreated control cultures. These results support that some metals may alter immune responses and thereby contribute to a variety of dental pathological conditions and three-dimensional cell culture models for gingival fibroblasts appear to be suitable for in vitro studies. [ABSTRACT FROM AUTHOR]