The Correlation between Cortical Bone Thickness and the Implant Stability Quotient (ISQ): A Systematic Review

Abstract

The advent of implantology, marked by Professor Per-Ingvar Branemark’s concept of osseointegration, revolutionised tooth replacement. A key indicator of successful osseointegration is implant stability, which can be categorised into primary stability (initial mechanical fixation) and secondary stability (biological integration through bone remodelling). The overall success of a dental implant is largely dependent on achieving both forms of stability. This systematic review investigates the correlation between cortical bone thickness and the Implant Stability Quotient (ISQ), a key metric for assessing the stability and osseointegration of dental implants. Recognising the critical role of implant stability in the long-term success of dental prostheses, the review explores the biological and mechanical factors underpinning primary and secondary stability. It emphasises the significance of osseointegration, first conceptualised by Branemark, and the increasing use of resonance frequency analysis (RFA) as a non-invasive method for monitoring implant integration through ISQ values. Advances in imaging technologies, such as CT and CBCT, have improved preoperative assessment of cortical bone thickness, a parameter hypothesised to influence ISQ by enhancing mechanical engagement. However, inconsistencies in imaging data and variations in study outcomes have led to inconclusive findings regarding this relationship. By systematically evaluating current literature, the review aims to determine whether cortical bone thickness can serve as a reliable predictor of implant stability. The findings suggest a potential association but underscore the need for further standardised, high-quality research to validate cortical bone thickness as a predictive tool in implant dentistry.