Dina Ihab Kamal Amin Yacoub, Amr A. Shabka, Maha El Baz And Mona Fadel,

ABSTRACT

Objectives: The Aim Of This Study Was To Evaluate The Fracture Resistance Of Four Different Resin Composite Materials; Two Ormocer Based And Two Non-ormocer Based Materials, To Restore Mesio-occlusal-distal Cavity Preparations Of Two Widths, Either 1/3 Inter-cuspal Distance Or 1/2 Inter-cuspal Distance. Methods: 80 Freshly Extracted Human Premolar Teeth Were Selected For This Study. Teeth Were Randomly Divided Into 2 Groups Of 40 Teeth Each, According To Cavity Width. Group B1: Cavity Width Was Prepared 1/3 The Inter-cuspal Distance And Group B2: Cavity Width Prepared 1/2 The Inter-cuspal Distance. Each Group Was Furtherly Subdivided Into 4 Subgroups Of 10 Teeth Each, According To The Type Of Restorative Material Used. MOD Cavities Were Prepared And Standardized In All Dimensions Except For The BL Width Of The Cavity. Etch And Rinse Adhesive System Futurabond M+ Was Used For All Specimens. Resin Composite Restoration Was Applied Either Incremental Or Bulk According To The Type Of Restorative Material: Admira Fusion Xtra (ormocer-based Bulk-fill Composite); Admira Fusion (ormocer-based Incremental Composite); Xtra Fil (conventional Bulk-fill Composite); Or GrandioSo (conventional Incremental Composite). All Teeth Were Tested For Fracture Resistance In A Universal Testing Machine With A 5 Mm Diameter Stainless Steel Sphere Applied On The Inclined Planes Of The Buccal And Lingual Cusps Of The Tested Specimens At A Cross-head Speed Of 0.5 Mm/min Until Fracture Occurred. Data Was Statistically Analyzed Using Three Way ANOVA To Compare Between Tested Materials, Application Technique And Cavity Width For Mean Fracture Resistance (N). Independent T-test Was Used To Compare Between Different Materials, Application Technique And Cavity Width Within Each Variable. Significant Level Was Set At P<0.05.

Results: Results Showed That Ormocer Based Composites Showed Significantly Lower Fracture Resistance Compared To Non-ormocer Based Materials. Regarding The Effect Of Application Technique, Bulk Fill Technique Showed Significantly High Fracture Resistance When Used To Restore Cavities Of 1/3 ICD. While Incremental Technique Showed High Significant Fracture Resistance In Cavities Of 1/2 ICD.

Conclusions: Ormocer Based Composites Did Not Improve The Fracture Resistance Of Teeth When Compared To Conventional Composites. The Fracture Resistance Of Teeth Was Not Influenced By The Technique Of Composite Application (incremental And Bulk Fill). Clinical Significance: The Cavity Width Seemed To Be The Only Factor That Really Had An Effect On The Fracture Resistance Of The Teeth.