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Three-dimensional analysis of cavity wall deformation after composite restoration of masticatory teeth

 

Neshka А. Manchorova-Veleva1
1Department of Operative Dentistry and Endodontics, Faculty of Dental Medicine, Medical University, Plovdiv, Bulgaria
Correspondence and reprint request to: Neshka А. Manchorova-Veleva, Dept. of Operative Dentistry and Endodontics,Faculty of Dental Medicine, Medical University, Plovdiv, Bulgaria; E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.;Mob.: +359 888 853 9423 Hristo Botev Blvd., 4002 Plovdiv, Bulgaria

Citation Information: Folia Medica. Volume 53, Issue 4, Pages 53–59, ISSN (Online) 1314-2143, ISSN (Print) 0204-8043, DOI: 10.2478/v10153-011-0068-8, October 2012
Publication History:
Published Online:
2012-10-24

 


ABSTRACT

 

AIM: The aim of the present work was to study the size of cavity wall deformation in eight class I and II defects after composite restoration.

MATERIALS AND METHODS: 1. Creating a geometric model - data on the size of the left maxillary second premolar were obtained from a routine craniofacial scanning of a 20-yearold patient with a 2,5 Dental CT scanner (General Electric), with high resolution and 0.625mm-thin slices. The contour of each of the 33 cross-sections of tooth 25 was delineated using graphics software (CorelDraw 7.0) and transferred to a specialized product for engineering design (SolidWorks Offi ce Premium 2010, SolidWorks Corp. USA). The pulp cavity and periodontal ligament were created in the same manner and were integrated in the premolar body; 2. Generation of a fi nite element method - the geometric model was exported

to specialized software for analysis by the fi nite element method - COSMOSWorks 2010, which automatically builds a 3D fi nite elements mesh. Based on the generated model, eight additional models of class I and II cavities with different geometries, adhesive layer and nanofi lled composite restorations were constructed. The polymerization shrinkage was modelled by thermal deformation, with a negative temperature difference (cooling), corresponding to the actual volume shrinkage of the composite materials by 2.1%.

RESULTS: In models A and B, the maximum cavity wall displacement was small - 0.014 mm and 0.015 mm, respectively. In models A1, B1, C1 and C, the displacement was at the expense of large deformation of the dental tissues. The maximum cavity wall displacements were 0.020 mm, 0.026 mm, 0.020 mm, 0.035 mm, respectively. The least cavity wall displacement was in models A2 and B2 with 0.008 mm and 0.017 mm, respectively.

CONCLUSIONS: The least displacement resulting from cavity wall deformation is found in patient-friendly class I and II preparations. Preservation of the dental tissues reduces the risk of mechanical pressure on the dentinal lymph and the likelihood of post-operative sensitivity.