Comparative Clinical Study of Implant Stability and Peri-implant Bone Loss in Two Implant Designs

Dental implants have become a widely accepted and predictable treatment modality for the rehabilitation of partially and completely edentulous patients. The long-term success of dental implants is primarily dependent on achieving and maintaining adequate implant stability and preserving peri-implant bone levels. Implant stability is influenced by several factors, including bone quality, surgical technique, and implant design. Among these, implant macro-design-particularly thread configuration and body geometry-plays a critical role in determining primary stability and stress distribution at the bone-implant interface.

Implant designs vary in terms of thread pitch, depth, and number of threads, as well as body shape (straight/cylindrical versus tapered/conical). Conical implants are believed to enhance primary stability by generating compressive forces within the surrounding bone, especially in areas of low bone density. Similarly, multiple-thread configurations may increase bone-to-implant contact and improve insertion efficiency and mechanical engagement. However, the combined influence of thread design and implant body geometry on implant stability and peri-implant bone behavior remains an area requiring further clinical investigation.

The present study was designed as a randomized, prospective interventional clinical trial with a parallel-group design to evaluate and compare implant stability and peri-implant marginal bone loss between two implant systems with different macro-design characteristics. A total of 30 patients requiring implant-supported restoration in the posterior mandibular region were included. Participants were randomly assigned into two groups using a computer-generated randomization method to ensure unbiased allocation.

Group A received double-threaded straight-body implants, while group B received triple-threaded conical-body implants. All implant placements were performed under standardized clinical conditions using a two-stage surgical protocol. Preoperative clinical and radiographic assessments were carried out to determine bone quality, quantity, and suitability for implant placement. Implant dimensions (diameter and length) were selected based on available bone at the implant site.

Primary implant stability was measured immediately after implant placement using resonance frequency analysis, which provides implant stability quotient values as an objective and non-invasive measure of stability. The same measurements were repeated at 3 months and 6 months postoperatively to evaluate changes in stability over time, reflecting the transition from primary mechanical stability to secondary biological stability during osseointegration.

Peri-implant marginal bone levels were assessed using standardized intraoral periapical radiographs obtained using a paralleling technique with grid calibration. Mesial and distal bone levels were measured relative to the implant platform at baseline, 3 months, and 6 months. These measurements were used to evaluate bone remodeling and marginal bone loss during the early healing phase.

All patients were followed up at regular intervals to monitor clinical healing, implant stability, and peri-implant tissue health. Postoperative care and follow-up protocols were standardized for all participants to minimize variability. Radiographic measurements were performed twice by the same examiner to ensure consistency, and intra-examiner reliability was evaluated.

The primary objective of the study was to compare implant stability between the two implant designs over time. The secondary objective was to evaluate and compare peri-implant marginal bone changes associated with each implant design during early healing.

The underlying hypothesis of the study was that triple-threaded conical-body implants would demonstrate superior implant stability due to enhanced mechanical engagement and compressive force distribution, while both implant designs would show comparable peri-implant bone response within clinically acceptable limits.

The results of this study are expected to contribute to the existing body of clinical evidence regarding the role of implant macro-design in influencing stability and bone preservation. This information may assist clinicians in selecting appropriate implant systems based on clinical requirements, thereby improving treatment outcomes and long-term success in implant dentistry.