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.

Within the limits of this in vitro study, it can be concluded that the investigated overdenture attachment systems are sufficiently resistant to wear. However, the Dalbo(®) -Plus- and SFI(®) -Bar- exhibit higher retentive capacities than the Locator(®) -attachment over time. The fixation screw of the SFI(®) -Bar may loosen during long-term use, but these observations might be less important if 1-year recall intervals are respected. An angulation of up to 12° between implants does not seem to have a significant effect on attachment wear.

This study compared the biocompatibility, mechanical properties, and surface roughness of a pre-polymerized polymethyl methacrylate (PMMA) resin for CAD/CAM complete removable dental prostheses (CRDPs) and a traditional heat-polymerized PMMA resin. Two groups of resin substrates [Control (RC): conventional PMMA; Test (RA): CAD/CAM PMMA] were fabricated. Human primary osteoblasts and mouse embryonic-fibroblasts were cultured for biocompatibility assays. Mechanical properties and surface roughness were compared. ANOVA revealed no difference between the resin groups in the biocompatibility assays. RA demonstrated a higher elastic modulus (p=0.002), young's modulus (p=0.002), plastic energy (p=0.002), ultimate strength (p=0.0004), yield point (p=0.016), strain at yield point (p=0.037), and toughness (p<0.0001); while RC displayed a higher elastic energy (p<0.0001). Laser profilometry concluded a rougher surface profile (p<0.0001) for RA. This study concluded that the tested CAD/CAM resin was equally biocompatible and presented with improved mechanical properties than the traditional heat-polymerized PMMA resin used in the fabrication of CRDPs.

Objectives: This review evaluated implant survival in geriatric patients (≥75 years) and/or the impact of systemic medical conditions. Materials and Methods: Systematic literature searches were performed to identify studies reporting on geriatric subjects with dental implants and on implant patients who had any of the seven most common systematic conditions among geriatric patients. Meta-analyses were performed on the postloading implant survival rates. The impact of systemic medical conditions and their respective treatment was qualitatively analyzed.Results: A total of 6,893 studies were identified; of those, 60 studies were included.The fixed-effects model revealed an overall implant survival of 97.3% (95% CI: 94.3, 98.7; studies = 7) and 96.1% (95% CI: 87.3, 98.9; studies = 3), for 1 and 5 years, respectively. In patients with cardiovascular disease, implant survival may be similar or higher compared to healthy patients. High implant survival rates were reported for patients with Parkinson's disease or diabetes mellitus type II. In patients with cancer, implant survival is negatively affected, namely by radiotherapy. Patients with bone metastases receiving high-dose antiresorptive therapy (ART) carry a high risk for complications after implant surgery. Implant survival was reported to be high in patients receiving low-dose ART for treatment of osteoporosis. No evidence was found on implant survival in patients with dementia, respiratory diseases, liver cirrhosis, or osteoarthritis.Conclusions: Implant prostheses in geriatric subjects are a predictable treatment option with a very high rate of implant survival. The functional and psychosocial benefits of such intervention should outweigh the associated risks to common medical conditions.

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