Bone strain measurements and implant micro-surface analysis of drill-less self-threading dental implants-preliminary in-vitro results

Innovative implant thread design enables timesaving one-stage insertion, with no need for prior osteotomy. This technique may impair bone and implant surface. The aim of this study was to investigate the strain levels produced in surrounding bone by this new treatment approach during and after implant placement and the effect of high insertion torque on the surface microstructure of the implants. Fresh bovine bone was collected and prepared to receive 2 types of drill-less self-threading dental implants differing in their thread design. Prior to implant insertion, two strain-gauges were cemented onto the bovine bone at each of the implant’s neck recipient sites, one horizontally and one vertically. 5 Type 1 and 5 Type 2 implants were inserted into the bone with insertion torque of 80 Ncm. Strain was measured during implant insertion, and residual strain was recorded for 1 hour after implant placement. Implants micro-structure were analyzed by SEM. These results were compared to osteotomy and implant insertion strain data of conventional dental implants. A clear pattern of higher vertical compared to horizontal strain levels can be seen in the drill-less implants, compared to the opposite in drilling and insertion of conventional implants. Type 2 drill-less implant showed the lowest strain levels of all groups. Highest horizontal strain levels were measured for insertion of standard implants. Strain recovery was least prominent in the insertion stage of standard implants. Significant more cervical compression zones were detected in type 1 implant. However, SA and Rx. Surface roughness measurements didn’t show any differences. Favorable horizontal stress distribution was noted in the 2 types of the novel drillless implants, and comparable or lower vertical strains compared to regular protocol was also noted. Residual strain was low within all dimensions of bone. Conventional implant insertion protocol delivers strain to the frequently vulnerable bone around the implant neck. Horizontal residual strain, both in drilling and inserting conventional implants, was higher than the insertion strain of the drill-less implants. Implant surface roughness was not impaired by high insertion torque. High torque implant insertion may induce positive strain distribution within coronal part of the supporting bone. Implant surface were not impaired by high torque insertion methods.