20  dentate subjects with one or two missing teeth will be selected. The study procedure will be explained to the subjects and with prior consent of the subjects the study will be further conducted.All necessary investigations before implant placement will be carried out. 7 implants will be placed with abutment implant complex/microgap,machined collar supracrestally and other 7 implants will be placed with abutment implant complex/microgap,machined collar subracrestally by following proper manufacturer’s instructions.

Implant stability will be measured by periotest instrument immediately after implant placement and 6  months after implant placement with implant mount in place in  both technniqe. The readings will be correlated with a grading scale provided by manufactures of periotest instrument. This study was also undertaken to evaluate marginal bone loss on the mesial and distal side of the implant, by  Digital opg  in both technique at the end of six months after placing the implants, but before prosthetically loading it. A  Digital opg and an IOPA  X-ray was taken on the day of implant placement, one hour after  the surgery. Crestal bone loss was measured on opg taken on the same machine, which was used for opg at the time of implant placement. The distance between the top of the implant and the level of crestal bone (first bone to implant contact) along the implant surface on mesial and distal side was measured on the opg  machine monitor, using its software. The measured value was auto-corrected by the in-built software for radiographic magnification factor.

All readings will be filled in the proforma for the study as given below and results will be analyzed.

Keeping this in mind, a study will be  undertaken to evaluation of  effect of placement of abutment–implant complex/microgap,machined collar on implant stability and marginal bone level changes of  unloaded  2-piece implants six months after the implant placement. The site was  kept common in  lower posterior region .