Are intraoral radiographs reliable in determining peri-implant marginal bone level changes? The correlation between open surgical measurements and peri-apical radiographs

This study was performed to evaluate the reliability of peri-apical radiographs in determining peri-implant marginal bone level changes. The STROBE guidelines were followed. Marginal bone levels were measured at the time of implant insertion using a straight periodontal probe and using peri-apical radiographs. These intraoperative and radiographic measurements were repeated at the time of second surgery. All radiographs were analysed by two examiners blinded to the intraoperative measurements. To standardize the radiographic images, the long-cone parallel technique and a film-holding system were used. Intra-observer agreement and inter-observer variability were assessed using the intra-class correlation coefficient (ICC). Descriptive statistics, the t-test, and the Pearson correlation coefficient were also used. A total of 268 implants were inserted in 142 patients. Inter-observer agreement was 0.950; intra-observer variability was 0.980 and 0.973. The mean difference between the radiographic and intraoperative measurements was 0.50 +/- 1.55 mm (range 0-8 mm); the difference was statistically significant (P = 0.000). A significant linear correlation was found between the marginal bone level changes evaluated intraoperatively and radiographically (P < 0.005). Radiographic analysis significantly overestimated the level of peri-implant marginal bone compared to intraoperative measurements, but peri-apical radiographs are reliable in determining the bone level changes at different follow-ups.