Implant Stability Quotients of Osteotome Bone Expansion and Conventional Drilling Technique for 4.1 mm Diameter Implant at Posterior Mandible

Background: Clinical conclusions in studying the stability and osseointegration of mandibular implants positioned using the bone expansion techniques are conflicting and limited. Purpose: The objective was to examine the implant stability quotient (ISQ) values of mandibular posterior dental implants with 4.1 mm diameter that inserted with osteotome bone expansion technique versus conventional drilling technique during a 12-week observation period. Materials and Methods: Twenty-four implants with 4.1mm diameter in 18 patients were included. Twelve implants in 10 patients were positioned using osteotome bone expansion technique, and 12 fixtures in 9 patients were installed using the conventional drilling technique. The ISQ values of a 3.3 mm diameter implant was measured at recipient sites (ISQ_b) before final drilling or expansion technique to standardize the increased ISQ value of 4.1 mm diameter implants. The ISQ values at Weeks 0, 1, 2, 3, 4, 6, 8, 10, and 12 post-surgery were recorded. Data were analyzed by Wilcoxon rank sum test, repeated measure ANOVA, and Fisher Lest Significant Difference test. Results: Calibrated according to a 3.3-mm-diameter implant, bone expansion technique was adopted for the sites with ISQ≦65 bone density, and the areas with ISQ >65 bone condition were treated with conventional drilling technique (p =.038). Both groups presented a similar healing pattern and a comparable ISQ reading from Week 0 to Week 12 (p >.05) for 4.1 mm diameter implants. However, bone expansion technique could enhance more stability when the ISQ values were calibrated by 3.3 mm diameter implant (p <.05). Conclusions: Bone expansion technique substantially increased more ISQ values from primary stability and achieved comparable primary and secondary stabilities with the conventional technique. Both groups reached a stability plateaus at Week 10.