Definition of a drilling protocol for mini dental implants in different bone qualities.

ABSTRACT

Mini dental implants (MDI) have proven to be a good alternative of the conventional implants to support lower overdentures in elderly edentulous patients with narrow residual ridge. The aim of the present study was to define drilling protocols for each diameter of the MDI in each bone quality. The number and the diameter of the drilling bur and the drilling depth was investigated. A total of 48 MDIs with a ball head and transgingival collar were used to the drilling protocol in four different bone qualities (Q1-Q4). All available four diameters of the implants were included 1.8mm, 2.1mm, 2.4mm, and 2.9mm. The length of all implants was 15mm. Three different protocols were prepared for each of the four bone qualities and for each implant diameter. The insertion torques and the primary stability of the implants were measured in their final position. Regardless of implant diameter and bone quality, the insertion torque was significantly higher using drilling protocol 1 than 3 and using drilling protocol 2 than 3 as well. The insertion torque was significantly higher in bone quality Q1 than in Q2-Q4. The unscrewing resulted in considerably increase in the torque, which exceeded the insertion torques by up to two times. This repeatedly led to the bending and fractures of implants.