Effect of Undersized Drilling and Sequential Osseodensification on Primary Implant Stability in Simulated Bone Types III and IV: An In Vitro Study
Purpose Primary implant stability is a key factor for successful osseointegration and may be influenced by osteotomy preparation techniques, particularly in low‐density bone. Thus, this study compared undersized drilling (UD), UD combined with osseodensification, and sequential osseodensification protocols with varying degrees of undersizing in simulated bone types III and IV with respect to implant stability. Additionally, the relationships between insertion torque (IT), removal torque (RT), and implant stability quotient (ISQ) were analyzed. Materials and Methods Eighty implants (4.0 × 11 mm) were placed in polyurethane blocks simulating type III and IV bone with a cortical layer. Four osteotomy protocols were tested: UD, UD plus osseodensification (OD1), and sequential osseodensification with −0.5 mm (OD2) and −0.7 mm (OD3) undersizing. Primary stability was assessed using IT, RT, and ISQ measurements. Data were analyzed using two‐way ANOVA, Pearson correlation, and multiple regression analysis (α = 0.05). Results OD2 and OD3 produced higher IT values in both bone types compared with UD and OD1. In type III bone, OD3 showed the highest RT values, while in type IV bone, OD2 and OD3 were significantly higher than UD and OD1. ISQ values were higher for osseodensification protocols in type III bone, whereas no significant differences were observed in type IV bone. A strong correlation was found between IT and RT (r = 0.746), whereas ISQ showed weaker associations with torque. Conclusion The use of sequential osseodensification protocols yielded superior mechanical stability parameters, specifically in IT and RT, in synthetic (polyurethane) bone models. However, improvements in ISQ were predominantly noted in the denser type III model. Importantly, because the tested protocols involved different drill designs and underpreparation dimensions, these enhancements reflect the success of the overall surgical strategy rather than the isolated effect of osseous densification.