Correlating Radiographic Fractal Analysis at Implant Recipient Sites with Primary Implant Stability: An In Vivo Preliminary Study.

Objectives The aim of this study was to demonstrate a possible correlation between radiographic trabecular bone quantified with fractal dimensions analysis and values of primary implant stability deliberated using the Osstell® monitor (Integration Diagnostics AB, Goteborgsvagen, Sweden) with the density of bone specimens harvested from the implant recipient sites and calculated using the mass and volume of the bone bloc specimens. Material and methods Fifty implants of the same brand, diameter, and length were inserted with the same surgical procedures; 25 implants in the molar premolar region of the maxilla and 25 implants in the mandibular posterior region of only healthy male patients between 20 and 50 years of age. Prior to the placement of the implants, biopsies were taken from the selected site for density calculation using a calibrated trephine. Two photostimulable phosphor digital periapical radiographs were obtained for each patient and two regions of interest were selected for a fractal dimension analysis: one site before implantation and the same site immediately postoperatively adjacent to the implant. Results There were correlations between the fractal dimensions and implant stability quotient as well as between fractal dimensions and bone density. No significant difference was found between the fractal dimensions of pre- and postoperative periapical radiographs for the same region of interest and between implant stability quotient values of the maxillae and mandible sites. Conclusion All executed analyses were helpful in assessing the bone density in the recipient site of implant placement using fractal dimensions, offering complementary information about predictable bone density assessed on a periapical radiograph.

In vivo registration of force development with ceramic and acrylic resin occlusal materials on implant-supported prostheses.

PURPOSE: It has been hypothesized that the shock generation on implant-supported prostheses during chewing should generate higher implant loads if the veneering material is porcelain rather than acrylic resin. MATERIALS AND METHODS: The present study uses strain-gauged abutments to measure the force transferred to the implant after a shock has been applied. This was measured in vitro and in vivo in 5 patients. RESULTS: The different occlusal materials did not lead to different forces generated to the implants of the patients. DISCUSSION: From a practical point of view, the choice of occlusal material has no bearing per se on force generation to the implants. CONCLUSIONS: The present study demonstrated that there: (a) is a difference in resilience between acrylic resin and ceramic veneering materials, but (b) this difference is only measurable in in vitro where the force is generated by a shock only and the implant is rigidly anchored.