IADR Abstract Archives
Effects of Implant Macrodesign and Drilling Protocols on Primary Stability
Objectives: To investigate the effects of implant macrodesign and drilling protocols, in low-density artificial bone blocks, by monitoring primary stability parameters: implant insertion torque (IT); implant stability quotient (ISQ); periotest value (PTV) and implant micromotion (MM).
Methods: Polyurethane cellular-typed (10-pcf, density: 0.16 g/cc) sawbone blocks (30mm x15mm x19mm) with and without 1-mm lamination (50-pcf, density: 0.80 g/cc) were used to simulate cancellous bone with and without a thin cortical layer. Two different implant design (Nobel Biocare Mk IV-4.0, and NobelActive-4.3) were used. Implant site preparation was performed according to manufacturer's soft-bone protocol. In laminated group, standard drilling protocol (SDP), counterbore drill were used as the final drills before implant placement. In Modified drilling protocol (MDP), 2.4/2.8 twist step drill was used as the final drill. Five implants were tested for both SDP and MDP. IT, ISQ, PTV and MM were recorded for each implant. IT was recorded during implant placement, and then ISQ was measured. A 5-mm healing abutment was connected to the implant for measuring PTV and MM. MM was measured (1 mm above implant platform) with micro-miniature LVDT when a lateral force 10N applied to the top of healing abutment by a Dynamic Loading Machine. Mann-Whitney U test was performed for statistical analysis.
Results: Significantly increased IT and ISQ and decreased MM were noticed with the present of cortical bone. MDP significantly increased IT and decreased MM in Mk IV and NobelActive implants. However, no obvious changes were noted in ISQ and PTV with MDP.
Conclusions: The data suggest that low-density bone block with 1-mm cortical layer can significantly increase insertion torque and decrease micromotion. Modified drilling may improve implant stability indicated by increased insertion torque and decreased micromotion under loading. However, parallel changes could not be significantly observed with ISQ and periotest value.
Methods: Polyurethane cellular-typed (10-pcf, density: 0.16 g/cc) sawbone blocks (30mm x15mm x19mm) with and without 1-mm lamination (50-pcf, density: 0.80 g/cc) were used to simulate cancellous bone with and without a thin cortical layer. Two different implant design (Nobel Biocare Mk IV-4.0, and NobelActive-4.3) were used. Implant site preparation was performed according to manufacturer's soft-bone protocol. In laminated group, standard drilling protocol (SDP), counterbore drill were used as the final drills before implant placement. In Modified drilling protocol (MDP), 2.4/2.8 twist step drill was used as the final drill. Five implants were tested for both SDP and MDP. IT, ISQ, PTV and MM were recorded for each implant. IT was recorded during implant placement, and then ISQ was measured. A 5-mm healing abutment was connected to the implant for measuring PTV and MM. MM was measured (1 mm above implant platform) with micro-miniature LVDT when a lateral force 10N applied to the top of healing abutment by a Dynamic Loading Machine. Mann-Whitney U test was performed for statistical analysis.
Results: Significantly increased IT and ISQ and decreased MM were noticed with the present of cortical bone. MDP significantly increased IT and decreased MM in Mk IV and NobelActive implants. However, no obvious changes were noted in ISQ and PTV with MDP.
Conclusions: The data suggest that low-density bone block with 1-mm cortical layer can significantly increase insertion torque and decrease micromotion. Modified drilling may improve implant stability indicated by increased insertion torque and decreased micromotion under loading. However, parallel changes could not be significantly observed with ISQ and periotest value.
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