STATEMENT OF PROBLEM Complete dentures fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) techniques have become popular. The 2 principal CAD-CAM techniques, milling and rapid prototyping (3D printing), used in the fabrication of complete dentures have been reported to yield clinically acceptable results. However, clinical trials or in vitro studies that evaluated the accuracy of the 2 manufacturing techniques are lacking. PURPOSE The purpose of this in vitro study was to compare the differences in trueness between the CAD-CAM milled and 3D-printed complete dentures. MATERIAL AND METHODS Two groups of identical maxillary complete dentures were fabricated. A 3D-printed denture group (3DPD) (n=10) and a milled denture group (MDG) (n=10) from a reference maxillary edentulous model. The intaglio surfaces of the fabricated complete dentures were scanned at baseline using a laboratory scanner. The complete dentures were then immersed in an artificial saliva solution for a period of 21 days, followed by a second scan (after immersion in saliva). A third scan (after the wet-dry cycle) was then made after 21 days, during which the complete dentures were maintained in the artificial saliva solution during the day and stored dry at night. A purpose-built 3D comparison software program was used to analyze the differences in the trueness of the complete dentures. The analyses were performed for the entire intaglio surface and specific regions of interest: posterior crest, palatal vault, posterior palatal seal area, tuberosity, anterior ridge, vestibular flange, and mid-palatal raphae. Independent t tests, ANOVA, and post hoc tests were used for statistical analyses (=.05). RESULTS The trueness of the milled prostheses was significantly better than that of the rapid prototyping group with regard to the entire intaglio surface (P<.001), posterior crest (P<.001), palatal vault (P<.001), posterior palatal seal area (P<.001), tuberosity (P<.001), anterior ridge (baseline: P<.001; after immersion in saliva: P=.001; after the wet-dry cycle: P=.011), vestibular flange (P<.001), and mid-palatal raphae (P<.001). CONCLUSIONS The CAD-CAM, milled complete dentures, under the present manufacturing standards, were superior to the rapidly prototyped complete dentures in terms of trueness of the intaglio surfaces. However, further research is needed on the biomechanical, clinical, and patient-centered outcome measures to determine the true superiority of one technique over the other with regard to fabricating complete dentures by CAD-CAM techniques.
Initial attempts to fabricate complete dentures (CDs) with computer-aided design and computer-aided manufacturing (CAD-CAM) technology began in the 1990s 1-3 ; since then, there has been an evolution of the techniques and the associated technologies. 4-10 The infusion of CAD-CAM techniques into CD fabrication methods has led to the evolution of modified and easier clinical protocols, 11,12 the use of materials with improved properties, 13-18 better fit and retention of the CDs, 19-29 reduction in the chairside and laboratory times, 12,30-32 and overall reduction in clinical and laboratory costs. 30 High patient and clinician satisfaction with CAD-CAM CDs has been reported. 33-35 The CAD-CAM clinical protocols used are modified versions of the conventional clinical steps followed during the fabrication of CDs. Although promoted by various manufacturers as being more straightforward and easier, the CAD-CAM protocols require extended time to learn the procedure and to digitize the analog clinical procedures. 34,36 Elaborate instruments, depending on the manufacturing system, are often required to carry out these novel clinical protocols.
Purpose: This study aimed to validate an ageism scale for dental students in Switzerland. Methods: The original scale was first translated to German and then evaluated by 14 experts for relevance; four items were eliminated. Validation of the resulting questionnaire was performed at three Swiss dental schools. Principal component analysis (PCA) was performed; Cronbach's alpha (α) was used to assess the internal consistency reliability, and Pearson's coefficient to identify any correlations with demographic parameters (P < 0.05). Results: PCA revealed 11 items among 4 factors (Overall: 11 items, α = 0.63, variance = 56.6%; Factor #1 (F1): items = 3, α = 0.64; Factor #2 (F2): items = 3, α = 0.42; Factor #3 (F3): items = 3, α = 0.35; Factor #4 (F4): items = 2, α = 0.37). F1 and F4 were correlated with clinical experience (F1: P = 0.042; F4: P = 0.006) and participation in a gerodontology course (F1: P = 0.021; F4: P = 0.004). F1 was correlated with experience of dealing with the elderly (P = 0.031), while residence locality was correlated with F3 (P = 0.047) and F4 (P = 0.043). F2 was correlated with the presence of elderly in the family (P = 0.047). Conclusion:The translated dental ageism questionnaire for Switzerland resulted in an 11-item scale with acceptable reliability.
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