Investigation of marginal bone loss in implants with different surface properties and geometric designs: A retrospective clinical study

Objective: Dental implants are commonly used for the rehabilitation of total or partial edentulism to restore function and aesthetics. Therefore, studies focusing on achieving long-term success and detecting potential failures of dental implants are increasing. Marginal bone loss is one of the early radiological indicators of implant failure. In this study, our aim was to investigate the influence of surface characteristics and geometric design on marginal bone loss in dental implants. Additionally, we supported our data with fractal analysis to examine trabecular changes in the bone surrounding dental implants during functional loading. Method: A total of 378 implants from 114 patients were evaluated in this study using panoramic and periapical radiographs. Implants were categorized into 19 subgroups according to the jaw where they were placed, length, diameter, surface preparation, type of prosthetic superstructure, and neck design. Radiological evaluations were conducted based on radiographs obtained at the time of implant placement and 3 months after prosthetic loading. After obtaining measurements of marginal bone loss and fractal analysis data, the significance of differences between groups was statistically evaluated. The statistical package program IBM SPSS Statistics (version 26) was used for statistical analysis. Normality of continuous measurements was assessed using the Kolmogorov-Smirnov (n>50) and Skewness-Kurtosis tests, and parametric tests were applied as the measurements were normally distributed. A significance level of p<0.05 was used in the calculations. Result: Marginal bone loss measurements from the mesial and distal surfaces of the implants showed a positive correlation on both surfaces. The amount of marginal bone loss was significantly higher in the maxilla compared to the mandible when considering the changes between jaws (p<0.05). Analysis of variations among prosthetic superstructures revealed that single crown implants had the least marginal bone loss, while implant-supported removable prostheses had the highest marginal bone loss (p<0.05). Additionally, marginal bone loss was significantly lower in implants with coronal microthreads not exceeding 1 mm compared to those exceeding 1 mm (p<0.05). Fractal analysis data indicated a statistically significant increase in fractal values 3 months after prosthetic loading for all implants compared to preloading values. Moreover, the increase in fractal values was significantly higher in implants with coronal microthreads not exceeding 1 mm compared to those exceeding 1 mm. Conslusion: This study demonstrates that the geometric design of dental implants may have an impact on marginal bone loss, which is a determinant of long-term success. Furthermore, fractal analysis revealed an increase in trabeculation in function-loaded dental implants. However, considering that marginal bone loss has a multifactorial etiology, further studies are needed to identify other potential factors contributing to marginal bone loss. Key Words: Dental implant, marginal bone loss, dental implant design, fractal analysis, microthreads