Comparative evaluation of the fracture resistance of standard and modified mesio - occluso - distal class ii cavity designs with cention-n restoration: an invitro study

Objectives: The main goal of this study was to assess the fracture resistance of standard and modified mesio - occluso - distal class II cavity designs with cention-N restoration.
Material And Method: Forty eight extracted teeth were randomly divided into 6 Groups of 8 teeth each. G1 consists of intact teeth. G2 was prepared with separate proximal boxes. The proximal preparation was standardized in all test groups. G3 was prepared with an occlusal extension that extend approximately one-third of buccolingual width and 2 mm in depth. G4 were prepared with the occlusal extension of 1mm in depth and width and with retention locks. G5: The occlusal extension was set as 1mm in depth and 2 mm in width and with retention locks. G6: The occlusalextension were having 2 mm in depth and 1 mm in width with retention lock. Samples were restored with Cention N and subjected to load to evaluate the fracture resistance.
Result: Fracture resistance of G4(2419.38N) and G5(1958.73N) was significantly greater than G3(1457.75N). Fracture resistance of G4(2419.38N) and G5(1958.73N) was significantly greater than G6(1664.78N).There was no significant difference between G3 and G6.All the three MOD modified groups with retention locks showed increased resistance to fracture than standard MOD group with no retention locks.
Conclusion: In modified MOD designs, resistance to fracture was increased when the cavity was prepared within the enamel and when retention locks were given compared to standard MOD deigns.