International Journal of Health Sciences & Research (www.ijhsr.org) 156 Vol.7; Issue: 6; June 2017 International Journal of Health Sciences and Research www.ijhsr.org ISSN: 2249-9571 Original Research Article A Comparative Analysis of Microleakage around Composite Restoration and Zirconium Ceramic Inlay under Confocal Microscope - An In Vitro Study Dr. Datta Prasad S 1 , Dr. Ankanna T 2 , Dr. Sunil Kumar C 3 , Dr. Sasidhar Reddy K 3 , Dr. Hemadhri M 4 , Dr. Sunil Kumar S 5 1 Head of Department, 2 Post Graduate, 3 Professor, 4 Assistant Professor, 5 Senior lecturer, Department of Conservative Dentistry and Endodontics, C.K.S Theja Institute of Dental Sciences and Research, Tirupati, Andhra Pradesh. Corresponding Author: Dr. Ankanna T ABSTRACT Aim & Objective: To detect and compare micro leakage of nano composites and zirconia restorations done on extracted teeth using nano composites and zirconium restorative material under confocal microscope. Materials and Methods: 20 caries free maxillary premolars were collected for the study. Class II - box only preparation was done on all extracted teeth out of which 10 teeth were restored using nano composite (ivoclar) and remaining 10 teeth were restored with zirconium ceramic material designed using CAD\CAM. All samples were subjected to thermocycling followed by immersion in Rhodamine-B dye solution for 48 hrs. The samples were sectioned in mesiodistal direction using minitom and dye penetration observed under a confocal laser electron microscope. The results were subjected to statistical analysis. Results: Group II Zirconia ceramic material shows lesser microleakage than group I nano composite. Conclusion: Based on this study it is advisable to use Zirconia ceramic Material for restorative purpose to minimise the micro leakage, further studies with greater sample size is a must to prove its accuracy. Key words: Microleakage, composite, zirconia, thermo cycling, confocal microscope. INTRODUCTION “Something that is constant is change”. There have been more changes and developments in dentistry over the past decade than in the previous hundred years combined, and the pace is accelerating! In the current age of adhesive dentistry or micro dentistry, conservation of tooth structure is paramount. Rather than using extension for prevention as a treatment guideline, emphasis now is placed on restriction with conviction. [1] Microleakage is defined as the passage of bacteria, fluids or molecules between a cavity wall and the restorative material applied to it. [2] Microleakage may cause hypersensitivity, recurrent caries and pulpal pathoses. [3] Besides pulpal irritation and secondary caries, microleakage also results in marginal discoloration. It is one of the major problems in clinical dentistry. It is very important to achieve a micromechanical and biomechanical bond between the restoration and tooth as it is