Dosimetric evaluation of the effect of dental restorative materials in head and neck radiotherapy.

Background: The aim of our study is to assess the dose enhancement from scattered radiation due to dental restorative materials used for occlusal and mesio-occlusal-distal (MOD) cavity filling during simulated head and neck radiotherapy. Methods: We have studied the dose enhancement ratio (DER) of conventional amalgam, high-copper amalgam, and resin composite dental restorative materials at cadaver mandible teeth using 2 therapeutic photon energies of 1.25 MeV (Co-60 gamma ray) and 6 MV (Linac X-ray) for irradiation. Results: DER values at buccal position for Co-60 and 6 MV X-ray were 1.250 ± 0.013 and 1.151 ± 0.012, respectively. For dental cavity fillings, DER values for 6 MV X-ray were 1.065 ± 0.021, 1.100 ± 0.014, and 1.162 ± 0.016 for resin composite filling, low-copper amalgam filling, and high-copper amalgam filling, respectively. Our results revealed that DER regarding irradiation energy was minimum for 6 MV X-rays. With respect to dental restorative filling material, DER was minimum for resin composite filling. Regarding the cavity type, our results with standard deviation (SD) calculations revealed that DER was slightly but not significantly different for both Co-60 gamma ray (1.25 MeV) and 6 MV X-ray energies for both occlusal and MOD cavities. Conclusion: Our dosimetric results for a single beam geometry suggest that, among the three types of filling, resin composite filling is an ideal restorative filling material with minimal morbidity-inducing radiation dose enhancement that may result in increased osteoradionecrosis and secondary caries risk. There is a need for further dosimetric studies with actual clinical beam arrangements.

Investigating the color changes on resin-based CAD/CAM Blocks.

OBJECTIVE: The improvement of the optical properties of new generation dental ceramics enables more esthetic and durable restorations. This study aimed to investigate the color changes, caused by exposure to different beverages on composite, hybrid ceramic, and zirconia-reinforced lithium silicate (ZLS) CAD/CAM blocks. MATERIALS AND METHODS: CAD/CAM blocks 40 samples (1.5 × 7 × 12 mm) were obtained from each material under water cooling. Following the polishing process and the initial color measurement, the prepared samples were exposed to red wine, coffee, cola, energy drink, and distilled water. Color changes were measured by spectrophotometer at the end of the 1st, 7th, and 30th days. To analyze the color change results, one-way analysis of variance (ANOVA) test was performed. RESULTS: In all restorative material groups, the most prominent color changes were observed on the red wine-exposed samples, then the coffee-exposed ones. No significant discoloration was observed on the samples exposed to cola and energy drink, compared to the control group (P > .05). Among the samples exposed to red wine and coffee, the highest discoloration values were observed in composite CAD/CAM material. CONCLUSIONS: At the end of the 30th day, all materials exposed to wine and coffee showed color change above the clinically acceptable value (ΔE00 :2.25). CLINICAL SIGNIFICANCE: Hybrid ceramic and ZLS CAD/CAM blocks recently used more often by clinicians have shown similar color changes. The results of our study indicate the necessity of choosing esthetic materials according to the dietary habits of individuals.

Root canal configurations of third molar teeth. A comparison with first and second molars in the Turkish population.

The purpose of the current study was to determine the similarities of maxillary and mandibular third molars with the other molar teeth. A total of 2016 extracted maxillary and mandibular permanent teeth were evaluated. The teeth were divided into six groups. The teeth were stored in 5% nitric acid solution for 7 days, then placed in increasing concentrations of ethyl alcohol. The teeth were rendered transparent by immersion in xylene solution for 4 days until complete transparency was achieved. Three roots were present in 93.0% of the maxillary molars, and 91.3% of the second molars. Among the maxillary third molars, 35.5% were single-rooted and 24.9% of the mandibular third molars had single roots. Double roots were present in 69.2% of the mandibular third molars, and 5.4% had three roots. Four new root canal configurations were encountered in this study. The root canal configurations of the mandibular and maxillary teeth showed similarities with the results of other studies performed in different populations.