Thermal and Stability Outcomes of Different Osteotomy Techniques and Implant Macrogeometries in Type IV Bone: An In Vitro Study

Achieving reliable implant stability in type IV (D4) bone remains a clinical challenge due to thin cortical plates and low trabecular density, which increase the risk of early failure. Novel osteotomy techniques such as osseodensification and the OsseoShaper have been proposed, yet their combined effects with different implant macrogeometries are not fully understood. This in vitro study evaluated forty osteotomies in standardized polyurethane foam blocks simulating D4 bone density. Three site preparation protocols—conventional osteotomy, osseodensification, and OsseoShaper—were combined with two implant macrogeometries (parallel-walled conical and tri-oval tapered designs). Insertion torque (IT) was measured using a calibrated digital torque meter, and implant stability was assessed by resonance frequency analysis (ISQ). Intraoperative thermal changes were monitored with infrared thermography under constant irrigation. Statistically significant differences were observed among groups (p < 0.05). Osseodensification with parallel-walled implants achieved the highest stability, whereas osseodensification with tri-oval implants showed the lowest. Although osseodensification produced the greatest thermal rise, all values remained below the 47 °C osteonecrosis threshold. Within the study’s limitations, both osteotomy technique and implant macrogeometry significantly affected stability and thermal outcomes, with osseodensification plus parallel-walled implants providing the most predictable performance in D4 bone.