ABSTRACT
The gathering of clinical data on fractures of dental restorations through prospective clinical trials is a labor- and time-consuming enterprise. Here, we propose an unconventional approach for collecting large datasets, from which clinical information on indirect restorations can be retrospectively analyzed. The authors accessed the database of an industry-scale machining center in Germany and obtained information on 34,911 computer-aided design (CAD)/computer-aided manufacturing (CAM) all-ceramic posterior restorations. The fractures of bridges, crowns, onlays, and inlays fabricated from different all-ceramic systems over a period of 3.5 y were reported by dentists and entered in the database. Survival analyses and estimations of future life revealed differences in performance among ZrO2-based restorations and lithium disilicate and leucite-reinforced glass-ceramics.
Subject(s)
Ceramics/chemistry , Computer-Aided Design , Dental Materials/chemistry , Dental Restoration Failure , Dental Restoration, Permanent , Aluminum Silicates/chemistry , Crowns , Databases as Topic , Dental Porcelain/chemistry , Dental Veneers , Denture, Partial , Follow-Up Studies , Humans , Inlays , Materials Testing , Retrospective Studies , Survival Analysis , Zirconium/chemistryABSTRACT
BACKGROUND AND PURPOSE: Different digital software tools are available today for the purpose of designing anatomically correct anterior and posterior restorations. The current concepts present weaknesses, which can be potentially addressed by more advanced modeling tools, such as the ones already available in professional CAD (Computer Aided Design) graphical software. AIM: This study describes the morphogenic designer (MGD) as an efficient and easy method for digitally designing tooth forms for the anterior and posterior dentition. MATERIALS AND METHOD: Anterior and posterior tooth forms were selected from a collection of digitalized natural teeth and subjectively assessed as "average". The models in the form of STL files were filtered, cleaned, idealized, and re-meshed to match the specifications of the software used. The shapes were then imported as wavefront ".obj" model into Modo 701, software built for modeling, texturing, visualization, and animation. RESULTS: In order to create a parametric design system, intentional interactive deformations were performed on the average tooth shapes and then further defined as morph targets. By combining various such parameters, several tooth shapes were formed virtually and their images presented. CONCLUSION: MGD proved to be a versatile and powerful tool for the purpose of esthetic and functional digital crown designs.
Subject(s)
Computer-Aided Design , Dental Prosthesis Design , Software , Bicuspid/anatomy & histology , Cuspid/anatomy & histology , Esthetics, Dental , Humans , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Incisor/anatomy & histology , Molar/anatomy & histology , Principal Component Analysis , Therapy, Computer-Assisted , User-Computer InterfaceABSTRACT
Ceramic inlays and partial crowns have become scientifically recognized posterior restorations. Their clinical effectiveness depends on the development of durable dental ceramics and luting materials as well as an effective bonding system. Therefore, these factors were in the focus of interest in the past. In contrast, only little attention was given to preparation techniques. However, current studies show that special preparation rules should be followed to ensure best fitting CAD/CAM ceramic restorations and long-lasting clinical success. This paper describes preparation requirements by means of detailed three-dimensional schematic drawings and then deduces the clinical procedure for the preparation of ceramic inlays and partial crowns with standardized preparation instruments.