Examination of the influence of a reverse tapered body shift on the mechanical performance of dental implants in extraction sockets

Abstract

Background As a result of continuous development, changes in the macro geometry of dental implants over time have had a profound influence on their mechanical behaviour and the osseointegration process. Aim/Hypothesis The objective of the present in vitro study was to evaluate the mechanical performance of dental implants with macro geometric changes to the apical region, relative to conventional implants. Material and Methods Comparative insertion torque measurements were conducted between conventionally tapered implants and the newly designed reverse tapered body shift implants (see Figure 1). All implants were placed in simulated extraction sockets created in orthopaedically-certified synthetic bone blocks with a density of 0.32 g/cm3. The simulated extraction sockets were created by drilling a 5 mm deep osteotomy with a diameter of 5.3 mm, to ensure that the coronal section of the implants had no influence on the insertion torque performance. Thereafter, the osteotomies for the implants were prepared as per the manufacturers guidelines. For the sake of comparison, all implants had a total length of 11.5 mm and a coronal diameter of 3.0 mm, whereas the newly designed implant had a reverse tapered body shift with a diameter of 3.5 mm. Results In total, 40 insertion torque measurements were recorded (20 in the control group and 20 in the test group). The average insertion torque for the conventionally tapered implants was 8.45 Ncm (SD = 0.69), whereas the average insertion torque in the test group was 12.55 Ncm (SD = 1.61). To convert these in vitro results to a more clinically relevant situation, the percentage increase in insertion torque between the two groups was calculated. On average, the newly designed reverse taper body shift implant achieved 49% greater insertion torque, compared with a conventional implant of the same coronal diameter and length. Conclusions and Clinical Implications Reverse tapered body shift implants achieve an average of 49% greater primary stability in extraction sockets than conventionally tapered implants with the same coronal diameter and length. This may overcome issues with primary stability in cases of immediate placement. FIGURE 1