Evaluation of drilling techniques in enhancing initial primary stability and on osseointegration

Background

A bone drilling concept namely osseodensification, has been introduced for the placement of endosteal implants to increase primary stability through densification of the osteotomy walls. This study investigated the effect of osseodensification on the initial stability, bone mineral density and initial bone to implant contact of implant placed with osseodensification drilling and the conventional drilling.

Aim/Hypothesis

Aim is to validate the biomechanical properties of osseous densification. The hypothesis of the present study was that osseodensification would increase primary stability, periimplant bone density (%BV) and percentage of bone to implant contact compared to conventional drilling.

Materials and Methods

A total of 60 osteotomies (n = 30 conical and n = 30 cylindrical implants) were created in bovine bone samples using three preparation techniques- standard drilling, under preparation drilling and osseodensification drilling, with the bur rotating in a reversed direction which work as non-cutting edges to increase the density of the bone as they expand an osteotomy. The surgical process (temperature increase and torque), mechanical stability during the insertion of 4x10 mm diameter implant (implant torque and stability quotient), and bone imaging (CBCT, Micro CT) measurement of bone mineral density, were compared among the three preparation techniques.

Results

Undersized and Osseodensification drilling significantly increased insertion and removal torques compared to standard drilling. Implant stability quotient or temperature increase readings were not appreciably different among the three groups. An undersized osteotomy allows to increase implant initial stability but it is not able to modify the %BV around the implant as compared with osseodensification. Imaging methods showed increased bone mineral density around the periphery of osseodensification sites. The percentage of bone at the implant surface was increased by approximately three times for implants prepared with osseodensification compared with standard drilling.

Conclusion and Clinical Implications

The OD technique would increase implant primary stability, bone mineral density and the percentage of bone implant contact compared to conventional drilling. Additionally, this study validated the bone expansion attitude of osseodensification showing that wider implant diameter could be inserted in narrow ridge without creating bone dehiscence or fenestration. Future in vivo human studies are needed to confirm the results showed in the present study.