Effect of different proximal box depths on stress distribution in indirect inlay restorations with deep margin elevation: A three-dimensional finite element analysis
Maede Ghasemi, Atiyeh Feiz, Dorsa Ghasemi, Reza AbedinzadehABSTRACT
Background:
Restoration strength can be affected by differences in proximal box heights of mesio-occluso-distal (MOD) cavities. Leveling the box depths in MOD cavities using deep margin elevation (DME) can indirectly affect the restoration’s stress distribution.
Materials and Methods:
The study design was based on finite element analysis (FEA). Ten mandibular first molars with MOD cavities were modeled with varying proximal box depths and restored with either composite or ceramic inlays, with or without deep margin elevation (DME). Models were numerically analyzed using FEA. A force of 200 N was applied obliquely to the occlusal surface of the tooth. Stress distribution in the tooth and restorations was analyzed using the von Mises criterion.
Results:
Results showed that increasing unilateral depth of the proximal box had no effect on stress distribution in dentin and ceramic inlay and only led to an increase in stress of composite inlay. Application of DME exhibited no effect on the decrease of stress in these groups. By increasing bilateral depth of proximal boxes, stress on dentin increased. Use of bilateral DME reduced stress generated in dentin layer, which was more effective in ceramic inlay group. Compared to composite inlays, ceramic inlays tend to concentrate more stress, which resulted in reduced stress on tooth and possibility of tooth fracture.
Conclusion:
Different proximal depths of cavity box affected mechanical behavior of restored tooth. DME application was more effective on stress values in bilateral deep cavities compared to unilateral deep cavities.