Investigating inlay designs of class II cavity with deep margin elevation using finite element method

Abstract

Background This study evaluates the mechanical performance of deep margin elevation technique for carious cavities by considering the shape designs and material selections of inlay using a computational approach combined with the design of experiments method. The goal is to understand the effects of the design parameters on the deep margin elevation technique and provide design guidelines from the biomechanics perspective. Methods Seven geometric design parameters for defining an inlay’s shape of a premolar were specified, and the influence of cavity shape and material selection on the overall stress distribution was investigated via automated modelling. Material selection included composite resin, ceramic, and lithium disilicate. Finite element analysis was performed to evaluate the mechanical behavior of the tooth and inlay under a compressive load. Next, the analysis of variance was conducted to identify the parameters with a significant effect on the stress occurred in the materials. Finally, the response surface method was used to analyze the stress responses of the restored tooth with different design parameters. Results The restored tooth with a larger isthmus width demonstrated superior mechanical performance in all three types of inlay materials, while the influence of other design parameters varied with the inlay material selection. The height of the deep margin elevation layer insignificantly affected the mechanical performance of the restored tooth. Conclusions A proper geometric design of inlay enhances the mechanical performance of the restored tooth and could require less volume of the natural dentin to be excavated. Furthermore, under the loading conditions evaluated in this study, the deep margin elevation layer did not extensively affect the strength of the tooth structure.

Deep margin elevation—Present status and future directions

“…Figure 1 shows the results of the study selection process, which led to the inclusion of seven review articles, 4,13–18 six reports of clinical investigations, 19–24 24 reports of in vitro/in silico studies, 7,7,25–47 and one report of a dental healthcare survey 48 . Data extracted from these 38 articles are reported in detail in Tables 1, 2, 3, and 4.…”

“…To restore teeth after DME, inlays and onlays/overlays made from CAD‐CAM RBC blocks, lithium disilicate, or indirect RBC were most common in the included studies 7,20–23,27–29,31–33,35–37,39–42 . Of the included studies, only in vitro investigations used leucite‐reinforced glass and feldspathic ceramics 30,31,33,43,46 .…”

“…7,26,27,[29][30][31][32][33]33,[35][36][37][39][40][41][42][43]45,46 Nine study reports did not specify whether permanent molars, deciduous molars, or both were used. 27,[32][33][34][35][36][39][40][41] Premolars were selected in four studies, 25,28,44,47 while one study used typodonts. 38 Except for the investigation that used typodonts, none of the included laboratory studies simulated physiological interproximal contacts.…”

“…To restore teeth after DME, inlays and onlays/overlays made from CAD-CAM RBC blocks, lithium disilicate, or indirect RBC were most common in the included studies. 7,[20][21][22][23][27][28][29][31][32][33][35][36][37][39][40][41][42] Of the included studies, only in vitro investigations used leucitereinforced glass and feldspathic ceramics. 30,31,33,43,46 Evidence on F I G U R E 5 Sectional metal matrix to provide ideal marginal seal for the deep margin elevation (DME) material…”

Cervical Margin Relocation for Indirect Bonded Restorations: A Literature Review

“…Recently, a new finite element analysis method based on a three-dimensional numerical simulation of the clinical situation has been described in the literature to evaluate mechanical strength and stress distribution of the restored tooth. Based on the available evidence, the study investigated that CMR does not significantly affect the strength of the tooth structure (24). Although, other studies recorded that CMR technique resulted in a higher fracture resistance (14,15,19).…”