ABSTRACT
OBJECTIVES: To evaluate the influence of restorative materials used on the rehabilitation of MOD cavities and loading type, on biomechanical behavior of wedge-shaped (WS) lesions in endodontically treated maxillary premolars. The investigation was conducted by 3D finite element analysis (FEA) and strain gauge test. MATERIALS AND METHODS: Six models were generated, with MOD cavities and endodontic treatment: A (MOD amalgam restoration), R (MOD composite restoration), AL (A + cervical lesion (L)), RL, ALR (A + cervical lesion restored with composite (LR)), and RLR. Each model underwent two compressive loading (100N): axial and oblique-45° angle to the long axis on the buccal cusp. The models were analyzed by von Mises criteria. For strain gauge test, 14 standardized maxillary premolars were treated according to the groups described for FEA. Two strain gauges were bonded on each sample submitted to compressive loading in a mechanical testing machine. RESULTS: A presented higher stress concentration and strain values than R. Oblique loading promoted highest stress concentration and strain rates for all groups. ALR and RLR presented similar stress-strain distribution pattern when compared to A and R. CONCLUSION: The interaction between MOD cavity restored with amalgam and oblique loading propitiated the highest stress concentration and strain values on cervical region and WS lesion. CLINICAL RELEVANCE: The MOD cavity restored with composite resin is a better option than amalgam to improve the biomechanical behavior of wedge-shaped lesion, avoiding dental failure. In addition, the occlusal interferences must be removed, allowing homogeneous contact distribution and preventing WS lesion progression.
Subject(s)
Bicuspid/physiopathology , Composite Resins/chemistry , Dental Amalgam/chemistry , Dental Cavity Preparation/methods , Dental Materials/chemistry , Dental Restoration Failure , Dental Restoration, Permanent/methods , Tooth, Nonvital/physiopathology , Biomechanical Phenomena , Bisphenol A-Glycidyl Methacrylate/chemistry , Dental Stress Analysis , Elastic Modulus , Finite Element Analysis , Gutta-Percha/chemistry , Stress, MechanicalABSTRACT
Many dental students struggle for visual recognition when first exposed to the study of tooth cavity preparation in the operative dentistry laboratory. Rapid prototypes and virtual models of different cavity preparations were developed for the incoming first-year class of 2010 at the Dental School of Federal University of Uberlândia, Brazil, to help them to visualize the subtle differences in cavity preparations and are described in this article. Rapid prototyping techniques have been used in dental therapy, mainly for the fabrication of models to ease surgical planning in implantology, orthodontics, and maxillofacial prostheses. On the other hand, the application of these technologies associated with 3D-virtual models in dental education is waiting to be exploited, once they have significant potential to complement conventional training methods in dentistry.
