Clinical Relevance of Bone Density Values from CT Related to Dental Implant Stability: A Retrospective Study

Abstract

Purpose . The majority of the techniques used to assess the primary implant stability are subjective and empirical and can be used during or after the surgery. The aim of this study is to evaluate the bone density prior to surgery, in order to give recommendations to the clinician about the best surgical technique and the type of implant which is needed. Materials and Methods . A surgeon operated on 75 patients for 269 implants over the period 2010–2014. He required a CT to plan the surgery and he documented the type, the diameters, and the lengths of the implants, the insertion torque, and the ISQ values. At a later stage another clinician measured bone density and cortical thickness. We endeavoured to get the most accurate superimposition between the implants placed by the surgeon and those placed by the clinician. Results . In maxilla ISQ showed a significant positive correlation with HU values detected for coronal-buccal (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi>r</mml:mi><mml:mo>=</mml:mo><mml:mn fontstyle="italic">0.302</mml:mn></mml:math>; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mi>p</mml:mi><mml:mo>=</mml:mo><mml:mn fontstyle="italic">0.020</mml:mn></mml:math>) and middle-lingual (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mi>r</mml:mi><mml:mo>=</mml:mo><mml:mn fontstyle="italic">0.295</mml:mn></mml:math>; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mi>p</mml:mi><mml:mo>=</mml:mo><mml:mn fontstyle="italic">0.023</mml:mn></mml:math>). Torque showed a positive correlation with cortical bone thickness at the middle of the ridge (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M5"><mml:mi>ρ</mml:mi><mml:mo>=</mml:mo><mml:mn fontstyle="italic">0.196</mml:mn></mml:math>; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M6"><mml:mi>p</mml:mi><mml:mo>=</mml:mo><mml:mn fontstyle="italic">0.032</mml:mn></mml:math>). Conclusion . It is important to take into consideration the Hounsfield Units and the cortical thickness as predictive parameters during the preoperative assessment, with regard to the choice of the implant type as well as the surgical technique.