Bone-Preserving Osteotomy Strategies for Narrow Ridges: Comparative in Vitro Analysis of Densifying, Low-Speed Shaping, and Conventional Protocols

Abstract

Adequate ridge width and thermal control are critical for predictable implant site preparation. This in vitro study compared conventional osteotomy (CO), osseodensification (OD), and OsseoShaper (OS) protocols in standardized polyurethane foam blocks simulating narrow D2 ridges. A total of 18 osteotomies (n = 6 per group) were prepared under protocol-specific irrigation. Ridge width was measured at 3, 6, and 9 mm apical to the crest before and after osteotomy using a digital caliper, and expansion (Delta W) was calculated. Intraoperative thermal changes (Delta T) were recorded in real time with an infrared thermal camera. OD achieved consistent expansion at all depths (p < 0.05), while OS produced significant widening at the 3 and 6 mm levels; CO yielded only a minor but significant gain at the 3 mm level. At the intergroup level, OS showed significantly greater crestal expansion than CO at 3 mm (p = 0.006). All protocols generated comparable thermal changes (mean Delta T 7.4-8.2 degrees C), remaining well below the critical 47 degrees C threshold. Within the limitations of this in vitro model, OD and OS enhanced ridge expansion compared with CO, particularly at the crestal level, where expansion is most critical. All protocols maintained thermally safe profiles, supporting their clinical applicability.