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STATEMENT OF PROBLEM: Lighting conditions are an essential factor for accurately determining tooth color. However, the ideal lighting conditions for determining tooth shade are rarely met and are difficult to quantify. While the use of a standardized daylight lamp D55 can improve accuracy, its high cost limits its use in dental offices. The use of modern operatory treatment units for tooth color determination is promising, as they now allow for the adjustment of light source settings such as color temperature and intensity. However, studies are needed to determine whether they provide accurate color determination. PURPOSE: The purpose of this study was to assess the accuracy of visual tooth shade determinations under the adjusted light sources of 2 different dental treatment units in comparison with a standardized daylight lamp D55. MATERIAL AND METHODS: Dental treatment units from 2 manufacturers KaVoLUX 540 LED (LK) and LEDview Plus (LDS) were tested. The light sources of these units were adjusted to match daylight conditions. A daylight lamp (Dialite Color 7; Eickhorst & Co. KG) was used as a control (D55). A total of 49 participants (median age of 25 years, 30 women) underwent the Ishihara screening and received standardized training calibration. A total of 2205 clinical visual tooth shade determinations were performed with the Toothguide Training Box using the Vita 3D-Master shade guide under the 3 different lighting types. Each participant had 15 color determinations made under each of the 3 light settings. Color differences were analyzed by using the Kruskal-Wallis, Wilcoxon rank-sum, and chi-squared tests (α=.05). RESULTS: The type of lighting used for tooth shade determination had no significant effect on the accuracy of selected shade based on the ΔE00 metric (P=.133). Perfect matches were achieved in 50.8% of the cases under LK, 49.8% under LDS, and 53.6% under D55 light, with no significant difference among percentages (P=.315). Although there was a significant difference in time elapsed for shade determination by light type (P=.004), this difference was not clinically relevant (20.8 seconds for LK, 23.9 seconds for LDS, 21.9 seconds for D55). CONCLUSIONS: The accuracy of color determination for both examined dental operatory lamps was found to be comparable with that of the standard D55 daylight lamp when adjusted to specific settings.
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OBJECTIVES: To evaluate oral sequelae after head and neck radiotherapy (RT) when using two different types of intraoral appliances. Thermoplastic dental splints (active control) protect against backscattered radiation from dental structures. Semi-individualized, 3D-printed tissue retraction devices (TRDs, study group) additionally spare healthy tissue from irradiation. MATERIALS AND METHODS: A total of 29 patients with head and neck cancer were enrolled in a randomized controlled pilot trial and allocated to receive TRDs (n = 15) or conventional splints (n = 14). Saliva quality and quantity (Saliva-Check, GC), taste perception (Taste strips, Burghart-Messtechnik), and oral disability (JFLS-8, OHIP-14, maximum mouth opening) were recorded before and 3 months after RT start. Radiotherapy target volume, modality, total dose, fractionation, and imaging guidance were case-dependent. To evaluate intra-group developments between baseline and follow-up, nonparametric Wilcoxon tests were performed. Mann-Whitney-U tests were applied for inter-group comparisons. RESULTS: At follow-up, taste perception was unimpaired (median difference in the total score; TRDs: 0, control: 0). No significant changes were found regarding oral disability. Saliva quantity (stimulated flow) was significantly reduced with conventional splints (median -4 mL, p = 0.016), while it decreased insignificantly with TRDs (median -2 mL, p = 0.07). Follow-up was attended by 9/15 study group participants (control 13/14). Inter-group comparisons showed no significant differences but a tendency towards a better outcome for disability and saliva quality in the intervention group. CONCLUSION: Due to the small cohort size and the heterogeneity of the sample, the results must be interpreted with reservation. Further research must confirm the positive trends of TRD application. Negative side-effects of TRD application seem improbable.
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OBJECTIVES: To investigate the predictability and image quality of low-dose cone-beam computed tomography (LD-CBCT) in computer-guided implantology. METHODS: Pig cadaver mandibles were imaged using high-definition CBCT (HD-CBCT) and LD-CBCT (HD-CBCT: 85 kV, 6 mA, 14.2 s, 767 frames, 1184 mGycm2, voxel size 80 µm, effective dose 231 µSv; LD-CBCT: 85 kV, 10 mA, 2.1 s, 384 frames, 84 mGycm2, voxel size 160 µm, effective dose 16 µSv; Orthophos SL, Dentsply Sirona, Bensheim, Germany). Digital impressions were taken using intraoral scanning (IOS; Omnicam, Dentsply Sirona). Data of CBCT modalities and IOS were aligned. Forty-eight implants were planned virtually (24 implants per modality; Bone Level 4.1 × 10 mm; Straumann AG, Basel, Switzerland). Implants were inserted using templates by initial pilot drilling ("partially-guided implantation"). Implant positions were recorded using IOS. Geometric deviations between planned and definitive positions were assessed regarding implant apex, entry-point and angle. CBCT image quality was evaluated by raters twice on a four point scale. The results were exploratively compared (linear models, Mann-Whitney-U tests). RESULTS: Regarding implant apex, deviations were greater for LD-CBCT (mean 3.0±1.2 mm), as compared to HD-CBCT (mean 2.3±1.1 mm). For entry-point, no distinct difference was detected with a mean deviation of 1.4±0.9 mm in LD-CBCT, and 1.7±0.6 mm in HD-CBCT. Regarding angle, deviations were greater for LD-CBCT (mean 13.2±6.3°), as compared to HD-CBCT (mean 9.2±5.3°). The image quality of HD-CBCT provided to be better (mean 2.7±0.6) than that of LD-CBCT (mean 2.5±0.6). CONCLUSIONS: Within the partially-guided approach, the results underline the potential of LD-CBCT alternatively to HD-CBCT for computer-guided implantology. Advantages of HD-CBCT need to be balanced against the higher radiation dose.