Comparison of hard tissue density changes around implants assessed in digitized conventional radiographs and subtraction images

Abstract

Objectives: The aim of this in vivo study was to compare peri-implant bone density assessed by the mean gray value of the histogram in digitized conventional radiographs and two digital subtraction images (DSI) methods: linear and logarithmic.

Material and methods: Thirty-four patients were monitored by standardized periapical radiographs 1 week after surgery and 4 months later. The radiographs were digitized and manipulated by means of EMAGO software. Linear and logarithmic DSI were obtained, and a filter was added to the logarithmic image. Control and test regions were selected and the mean value of the gray level of the histogram of these selected areas was obtained. This process was carried out in the digitized conventional radiographs (DCR) and the two methods of DSI. After that, the images were divided into two groups, with and without bone loss, and statistical analysis was performed.

Results: The results indicate that differences between the jaws did not reach significance, in all the images and in the two groups with and without bone loss. Furthermore, there was no statistically significant difference between the radiographic density assessed in the DCR and the two methods of subtraction images.

Conclusions: Monitoring of peri-implant bone density by the mean gray value of the histogram in a selected area can be assessed either by linear and logarithmic DSI or by DCR.