Stability Behavior of 2 Different Designs of Implants Placed in Pterygoid Bone: An Anatomical Cadaveric Study

Objective: Implant placement to the pterygoid bone has become more popular in implant-supported prosthetic rehabilitation of full arch or posterior edentulous areas. However, this type of implant placement, which has anchorage points on the maxillary bone and pterygoid bone, sometimes poses difficulties for the clinician due to differences in bone density. For a stable implant placement, the macro design of the implant and related factors affect the success as much as the success of the clinician. In this article, the authors aimed to evaluate the 2 different dental implant macro-design behaviors in the pterygoid bone. For the clinician, it is difficult to place an implant in the pterygoid bone due to the anatomic position of the bone. Because of that, most of the time, a clinician has only one chance to prepare and place the implant in this bone. Because of this situation, it is important to know the behavior of the implant macro design and the effect of the design to the primary stability. Materials and Methods: Tapered and parallel implant types (NobelActive and NobelParallel, Nobel Biocare, Gothenburg, Sweden) were placed on the right and left sides of the maxilla of 10 fresh human cadavers. Using Osstell Mentor III and SmartPegs (Integration Diagnostics, Göteborg, Sweden), the resonance frequency measurements were made immediately after the implant placement. The 2 different macro-design types of implants were compared in terms of implant stability quotients (ISQ) values. Results: Our study showed that the pterygoid bone was ideal for biomechanical stability scenario in managing the edentulous solutions of posterior maxilla with the tapered and parallel types of dental implants. However, a significant difference was observed in terms of ISQ values between group 1 and group 2. Group 2 measurement values were significantly lower ( P <0.05) with total standard deviation of 5.36. Conclusions: Tapered macro-design implants showed better ISQ values than the parallel macro-design implants according to primary stability. Clinicians must evaluate the implant macro-design type to get better primary stability on the pterygoid bone due to the clinical complexity of the area. Results and their clinical impacts are also discussed in the study.