Retention of CAD/CAM milled denture bases in complete dentures

Abstract

Introduction. CAD/CAM (Computer - aided Design / Computer - aided manufacturing) complete dentures have increased in popularity and a wide variety of systems are currently available. This new technology offers rehabilitation of complete edentulous patients by manufacturing a milled denture by 2 - 3 average appointments, from taking impressions by intraoral scanner or laboratory scanner of master cast till the fixation of the complete denture. Aim of study. To analyze the existing literature research on CAD/CAM complete dentures and to determine their retention over the conventional dentures. Methods and materials. A comprehensive review of the literature was done through MEDLINE and PubMed database for research articles with keywords “CAD/CAM complete dentures vs conventional denture”, “complete digital dentures vs conventional complete dentures”, “computer-engineered complete dentures”, “complete milled dentures”, The inclusion criteria for selection were clinical studies, laboratory technical research papers, case reports, and review articles with a comparison between CAD/CAM and conventional processing techniques for complete dentures fabrication. Results. The electronic research through MEDLINE and PubMed resulted in more than 150 titles in the English language literature, and 10 were relevant to determine the advantages of CAD/CAM against conventional dentures. CAD/CAM technology offers: 1) accuracy of marginal fit and occlusal contacts; 2) retention and stability of denture base; 3) high esthetics; 4) decrease of human factor; 5) reduced number of visits. According to 14 sources, an in vitro evaluation and comparison of biocompatibility, mechanical properties, and surface roughness of a pre-polymerized PMMA resin for CAD/CAM CDs and a traditional heat-polymerized PMMA resin, biocompatibility was assessed. The tested CAD/CAM and heatpolymerized resins were equally biocompatible; CAD/CAM resins demonstrated improved mechanical properties (higher elastic modulus, ultimate strength, and toughness); higher roughness of the CAD/CAM resin specimens. Acrylic resin denture bases undergo dimensional changes during polymerization. Injection molding techniques are reported to reduce these changes and thereby improve physical properties of denture bases. The analysis of literature revealed the fact that CAD/CAM has better retention and biocompatibility treatment for complete edentulous patients and it offers the possibility to minimize the number of visits for this group of patients is the greatest advantage. Conclusion. The analysis of literature showed that CAD/CAM technology has large prospects in modern dentistry due accuracy and post manufacture process shrinkage. The quality of CAD/CAM milled dentures surpasses the quality of conventional complete dentures. So, there is improvement at the branch of digital prosthodontics and much more precision.