Sara Khaled Selim, Mai Mahmoud Yousry, Ahmed Abd El-Fattah Al-Zohairy And Mohamed Refaat El-Bialy ,

ABSTRACT
This Study Was Performed To Evaluate Microhardness And Fracture Resistance Of Sonic-fill Versus Bulk-fill Resin Composite Restorations. Materials And Methods A Total Number Of 80 Standardized MOD Cavities Were Prepared In 80 Maxillary Premolars. The Teeth Were Randomly Divided Into Two Equal Groups, Of 40 Teeth Each, According To The Material; Either SonicFill Resin Or X-tra Fil Resin Composite. Each Group Was Divided Into Two Equal Subgroups, Of 20 Teeth Each, According To Sonic Vibration Applied; Either Application Of Resin Composite Using Sonic Vibration Or Without Sonic Vibration. Each Subgroup Was Divided Into 2 Classes, Of 10 Teeth Each, According To The Aging Duration; Either After 24 Hours Or 12 Months In Artificial Saliva At 37?C. Five Teeth From Each Class Were Used For Microhardness Testing And The Other Five Were Assigned For Fracture Resistance Testing. An Extra Group Of Five Unprepared Teeth Was Used As Sound Control For Fracture Resistance Test. Vickers Microhardness Test Was Performed With Load Of 300 Gm For 10 Seconds, Then HV Hardness Scale Was Used At 3 Depths. For Fracture Resistance, Teeth Were Subjected To Compressive Axial Loading Until Fracture Occurred.

Results: Regarding Microhardness, The Results Showed That X-tra Fil Had A Higher Mean Microhardness Number Than Sonicfill, Also It Showed That Aging Increased The Mean Microhardness On All Specimens. On The Other Hand, Vibration Had No Effect On Mean Microhardness. Moreover, Neither Of The Three Variables Implicated In This Study Had Any Significant Effect On The Fracture Resistance Within The Restored Groups. Nevertheless, Sonicfill Showed No Significant Difference When Compared With Control Group When Applied Without Vibration.

Conclusions: Regarding The Materials, X-tra Fil Showed Higher Microhardness Value Than SonicFill. On The Contrary, SonicFill Was Advantageous Over X-tra Fil Regarding Fracture Resistance, When Applied Without Vibration. However, With Vibration, Both Materials Behaved Similarly. Sonic Vibration Did Not Influence The Microhardness Nor The Fracture Resistance Of Both Materials.