Assessment of Dental Implant

Overview

This study describes a novel methodology for the generation of a patient specific dental model for the evaluation of dental implants. The study used the +CAD module to integrate CAD models of the implant into the image based world. This enabled the strong meshing capabilities of the +FE module to be applied to the integrated model, efficiently generating an accurate mesh for FEA.

Characteristics:

  • Based on in vivo CT data
  • Segmentation tools rapidly generate model of boney regions
  • Reverse engineering of implant guide from CT
  • The +CAD module allows positioning and integration of CAD models into image
  • Robust, accurate meshing of integrated model
  • FE analysis performed directly on generated mesh using COMSOL Multiphysics®

Thanks to

Prof Gianni Frisardi (Department of Oral Rehabilitation, University of Sassari) and COMSOL, Italy

Image Processing

A clinical CT of a dental patient requiring two implants was imported into ScanIP. Using semi-automated, greylevel based segmen-tation tools it was possible to model the mandible and teeth. The model was then exported to +CAD where two dental screws were imported and manipulated into place using a further model of the patient’s moulded implant guide. These CAD models were then voxelised and exported back into ScanIP along with the original image model.

Mesh Generation

A hex dominant, mixed hexahedral/tetrahedral, mesh was generated for the combined implants and mandible. The mesh had conforming interfaces, with mesh decimation in areas of low topological change. Homogeneous material properties were assigned to the implants while modulus was assigned to the mandible and teeth based on the greylevel of the original CT.

Simulation

The mesh was exported to COMSOL Multiphysics® where boundary conditions were applied to simulate the patient biting. The stress results through the jaw were analysed to find possible stress concentrations around the implants. Using the method it was possible to rapidly implant the screws in different positions and identify the optimal configuration.