RESUMO
PURPOSE: Evaluating the distortion probability in impressions of completely dentate arches when different impression materials are used in relation to operator experience. MATERIAL AND METHODS: Twenty-eight students (group A) and 7 dentists (group B) performed 3 maxillary impressions on 28 students (participants), each using vinyl siloxane ether (VSE), polyether (PE), and irreversible hydrocolloid (IHC). Gypsum master casts were fabricated and subsequently digitized. Intraoral scans were taken as a control. Differences between master casts and intraoral scans were visualized by heatmaps and planar deviations were investigated. If planar deviations of >120 µm were found, the impression was rated as "distorted." An additional superimposition using the casts from VSE or PE was performed to confirm the presence of distortions. The relative number of surfaces with distortions in each impression was calculated. The procedure was repeated for a distortion threshold of 500 µm. The statistical analyses included measures ANOVA and post-hoc tests (a < 0.05). RESULTS: When 120 µm was considered as the threshold for distortions, IHC impressions showed higher distortion probability than PE impressions in group A (P = 0.003) and group B (P < 0.0001). In group B only, PE showed a lower distortion probability than VSE (P = 0.02). There was no difference between the study groups (P = 0.42). Considering 500 µm as a threshold for distortions, there was no difference between impression materials (P = 0.17) or study groups (P = 0.53). CONCLUSION: There were no statistic significant differences in relation to operator experience. Different impression materials had a significant impact on distortion probability. Polyether impressions showed the lowest distortion probability. Int J Prosthodont. 10.11607/ijp.8555.
RESUMO
STATEMENT OF PROBLEM: Scientific data analyzing the clinical outcomes and costs of complete dentures fabricated by using conventional and computer-aided design and computer-aided manufacturing (CAD-CAM) processes are lacking. PURPOSE: The purpose of this retrospective study was to compare the treatment duration, financial costs, and postdelivery adjustments of CAD-CAM and conventional removable complete dentures. MATERIAL AND METHODS: Thirty-two edentulous participants (16 women, 16 men; age 35-85 years) who had received either CAD-CAM (n=16) or conventional (n=16) maxillary and mandibular removable complete dentures provided by prosthodontists with a minimum of 2 years of experience were evaluated. The CAD-CAM denture systems were either DDS-AV (AvaDent Digital Dental Solutions) (n=11) or DD-IV (Wieland Digital Denture) (n=5). The total treatment period (days) was recorded at 3 different time points (T0: preliminary alginate impression; T1: denture delivery; T2: last scheduled postdelivery adjustment). Adjustments during the follow-up (after T2) were noted and included the removal of areas of excessive pressure, relining, or repairs. The costs of the dental treatment and the laboratory fees were calculated. The Wilcoxon rank sum tests were used for statistical analysis (α=.05). RESULTS: No statistically significant difference regarding the treatment duration between digitally and conventionally fabricated removable complete dentures was found: T0-T1 (P=.889); T1-T2 (P=.675); T2- T3 (P=.978). No significant difference was found in the number adjustments for areas of excessive pressure, relines, or repairs (P=.757, P=1.000, P=1.000) during the period. Laboratory costs of CAD-CAM removable complete dentures were significantly lower than those of conventional removable complete dentures (P<.001), but clinical fees were similar between groups (P=.596), resulting in a reduction in the overall total costs for the CAD-CAM removable complete dentures (P=.011). Regarding the number of clinical visits, neither the group (conventional/CAD-CAM (P=.945)/DDS-AV/DD-IV [P=.848]) nor the interaction group (conventional/CAD-CAM and DDS-AV/DD-IV)/period (P=.084/P=.171) showed any significant differences. CONCLUSIONS: CAD-CAM removable complete dentures can be considered a viable alternative to conventional removable complete dentures regarding treatment duration, clinical and follow-up visits, adjustments, and maintenance requirements.