We studied the fracture resistance of maxillary premolars restored with recent restorative materials. Fifty maxillary premolars were divided into five groups: Group 1 were unprepared teeth; Group 2 were teeth prepared without restoration; Group 3 were teeth restored with tetric ceram HB; Group 4 were teeth restored with InTen S; and Group 5 were teeth restored with Admira. The samples were tested using a universal testing machine. Peak loads at fracture were recorded. The teeth restored with Admira had the highest fracture resistance followed by those restored with InTen-S and tetric ceram HB. Prepared, unrestored teeth were the weakest group. There was a significant difference between the fracture resistance of intact teeth and the prepared, unrestored teeth. There was also a significant difference among the tested restorative materials. Teeth restored with Admira showed no significant difference when compared with the unprepared teeth. It was concluded that the teeth restored with Admira exhibited the highest fracture resistance.

The aim of this study was to evaluate the shear bond strength of ormocer-based restorative material bonded to tooth structure using specific ormocer and nonspecific resin-based adhesives. Human molars were prepared to obtain flat buccal enamel surfaces and flat occlusal dentin surfaces. Admira bond, and Prime & Bond NT, Excite, AdheSE, and Prompt-L-Pop were applied to the prepared enamel and dentin surfaces. Ormocer restorative material was inserted into a mold fixed onto the prepared tooth surfaces. The restorative material was applied and cured. The shear bond strength was measured using a universal testing machine. The highest bond strength was recorded for Admira bond. The non-specific adhesives (AdheSE and Prompt-L-Pop) were recorded the lowest bond strength. Etch & Rinse (Prime & Bond NT and Excite) adhesives were recorded an intermediate values. Admira bond usually showed cohesive failure in the material with enamel and cohesive and mixed failure with the dentin. Etch & Rinse adhesives showed mixed failure with the enamel and, mixed and adhesive failures with the dentin. Self-etching adhesives commonly exhibited adhesive mode of failure. So, Etch & Rinse, non-specific bonding agents can be used with Admira ormocer-based restorative material when the specific adhesive is depleted.