Undersized Implant Site Preparation to Enhance Primary Stability in Computer-Guided Flapless Surgery: Sequential Drilling Protocol

ABSTRACT

Keywords:Implant stability, drilling protocol, undersized preparation, implant mounter, implant sleeve Purpose: Achieving primary implant stability in areas with poor bone density is often challenging for the clinician. This modified surgical protocol might be beneficial in such situations in computer-guided surgery. The purpose of the present clinical application is to give the clinician the sequence and steps for undersized implant site preparation in areas with poor bone density.

Methods: After an evaluation of the bone density with the software on the CT scan, the implant diameter is chosen and the implant site is prepared. The bone level drill drives the first osteotomy. The last drill diameter used may change with respect to the bone quality D1, D2, D3 or D4, therefore remaining undersized in diameter. There are situations in D3, D4 bone qualities where we will remain undersized in length also with the last drill (up to the 7mm depth only), just to give the right path to the implant without losing primary stability. The implant is then inserted by setting the torque of the implant motor between 35 N-cmand 70 N-cm.

Results: The surgical drilling protocol allows the clinician to limit the number of drills and to use the pre-planned implant diameter as a reference point to chose the right drilling sequence. However, we must be ready eventually remove the implant and to prepare again if, when it stops, it is too far from the lower limit of the sleeve.

Conclusions: The results of this clinical application suggest that undersized implant site preparations may be helpful in enhancing primary implant stability in computer-guided surgery and that there are significant correlations among bone density, maximum insertion torque, implant mounter and drilling kit.