Evaluation Of Fracture Resistance Of Premolars Restored With Different Restorative Technique With Decoupling In Class II Composites Restorations
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Abstract
Background and aim : To analyse the outcome of decoupling technique by comparing and evaluating the fracture resistance in Class II (Mesio-occluso-distal [MOD]) composite restoration .
Methods and materials : The present study was conducted using 60 extracted premolars, 10 for each group of restorative material and technique. Class II (MOD) cavities were prepared maintaining uniform dimensions and samples were divided into six groups randomly (n = 10 each)
Group 1 (positive control) – Intact teeth ,
Group 2 (negative control)- Premolar teeth with unfilled MOD cavity.
Group 3 - Teeth restored with Universal Restorative Composite (3MFiltek Z350) by incremental layering technique without decoupling.
Group 4- Teeth restored with Universal Restorative Composite (3MFiltek Z350) after decoupling with flowable composite (3MFiltek Z350 XT) for 5 minutes.
Group 5- composite layering technique using Universal Restorative Composite (3MFiltek Z350) after decoupling with glass fibre (Interlig,Angelus) for 5 minutes.
Group 6 – Teeth restored with Bulk Fill Composite (tetric bulk flow ) after decoupling with glass fiber (Interlig Angelus) for 5 minutes.
Results : Decoupling technique significantly increased the fracture resistance. The highest fracture resistance was shown by Group 1- 1569.30N followed by Group 6 - 1421.30N. group 5 1395.80N , group 4- 1141.04N and 3- 981.92N . Group-2 showed the least mean fracture resistance of 845.50 N .
Conclusion : Decoupling with fibre in composite restorations significantly increased the fracture resistance among both the groups restored with composite layering technique and bulk fill technique. Decoupled class 2 restoration showed higher fracture resistance when compared to class 2 restorations without decoupling.
Clinical significance: This study confirms that decoupling with flowable composites or fiber reinforced composites reduces the adverse effects of polymerization shrinkage. This technique can be integrated into routine clinical practice to enhance the longevity , greater marginal adaptation and reduce the polymerization shrinkage stress , potentially reducing the failure rates of composite restorations .