Correlating implant stability to bone structure

Objectives: The aim of this study was to demonstrate a possible correlation between bone microarchitecture and primary implant stability.
Material and methods: Twenty-two implants (Ankylos^® and Straumann^®) were inserted into the maxillae and mandibles of human cadavers. Bone structure was determined by computed tomography in three specimens (male, age 53; female, 67; female, 80). A strict clinical protocol was used for implantation. Primary implant stability was measured by resonance frequency analysis (Osstell Mentor). The bone structure was analyzed by micro-computed tomography (CT). Bone histomorphometrical parameters were calculated and correlated to primary implant stability.
Results: Implant stability quotients (ISQ) ranged from 50 to 70% depending on the specimens and sites. Histomorphometry indicated differences in the bone microstructures of the specimens. However, ISQ values were not related to trabecular bone histomorphometrical parameters. The sole correlation was found between ISQ values and cortical bone thickness.
Conclusion: This study confirms the relevance for primary stability of cortical thickness around implants. The thickness of cortical bone can be assessed using a standard clinical CT.