AIM–A CBCT based technique for quantitative evaluation of voidsin root canal fillings done after endodontic proceduresOBJECTIVES–To find best quality of biomechanical preparation through hand vs. Rotary instrument.To find voids in two different obturation techniques i.e. single vs.  Thermoplasticized condensation.Materials and Methods: Forty maxillary premolars will be randomly divided into two groups, 20 teeth will be hand instrumented (H) and 20 will be instrumented with rotary instrument (ROT).Both the above groups will again be divided into 2 groups of 10 each on random basis.The “H–SC and ROT–SC” groups will be instrumented with hand ProTaper files and rotary system respectively and filled with SINGLE CONE compaction. The “H–TH and ROT–TH” groups will be instrumented with Hand ProTaper filesand rotary system respectively and filled with Thermoplasticized obturation system. The volume at the filling/dentine interface (i–voids) and voids surrounded by filling material (s–voids) will be measured using CBCT.The software used for calculating volume will be ANATOMAGE–INVIVO5 software (Anatomage. 303 Almaden Blvd, Suite 700. San Jose, CA 95110).Statistical Analysis:The inter group comparison was done using the One Way ANOVA and Independent t–test.Results:hand instrumented canal obturated with Thermoplasticized technique was having less amount of volume of voids than Rotary instrumented and obturated with single cone technique. Conclusion–Among the collected data Hand instrumented Canal was having less amount of volume of voids than Rotary instrumented.Single cone obturation technique was having highest amount of volume of voids than Thermoplasticized technique.