Abstract

Background: Mandibular molars lose hard tissue due to many factors, such as caries, wear, and ?old ?restoration replacement. To restore missing tooth structure, the dental ?material used should ?be biologically compatible with the surrounding tissues and ?capable of withstanding the ?forces of mastication. In addition, there ?are difficulties in isolating the deep proximal ?margins from oral fluids to take an accurate impression and cement the indirect ?restorations. ?Thus, Finite element analysis (FEA) is adopted to evaluate the influence of stress distribution of elevated cervical margin of ?deep distal caries using flowable composite with different levels of elevated margins on ?MOD mandibular molars CAD CAM indirect PEEK inlay.?

Methods: Three 3D mandibular left first molar models were prepared ?according to the level of elevated cervical margin of deep distal caries of (MOD). Stress ?distribution in FEA was analyzed using the von Mises theory, after applying vertical and ?oblique forces. Moreover, an oblique force of 600 N was used.

?Results: This study shows that oblique forces have resulted in stress values and ?stress concentrations in dental tissues and restorations higher than those caused by vertical forces in the three ?models.

Conclusions: We can conclude that badly broken-?down molars restored with PEEK CAD CAM indirect inlay and a 2 mm elevated I ?cervical margin of the deep distal cavity using flowable composite have the lowest stress ?on the gingival step, compared with a 1 mm elevated cervical margin and a PEEK inlay cervical margin of the deep distal cavity.