In Vitro Radiographic Detection of Cement Overhangs on Cement-Retained Implant Restorations

Purpose: The aim of this in vitro study was to investigate the potential of digital and conventional radiography to detect small amounts of residual dental luting cements around implant abutments. Materials and Methods: Artificial cement and aluminum overhangs in varying thicknesses, heights, and depths were radiographed adjacent to implant restorations with a radiovisiography sensor. Five trained evaluators were asked to identify the smallest depth of overhang that could be detected on radiographs. Results: For detection of cement overhangs adjacent to implant abutments, a luting agent must have greater radiopacity than what is recommended by relevant International Organization for Standardization directives. To detect a 0.1-mm-thick portion of excess cement adjacent to an implant abutment, the cement should have a radiopacity of at least 1.7 mm of aluminum for high-resolution digital radiographs and 2.2 mm of aluminum for film-based radiographs. Two-way analysis of variance revealed that the thickness of the specimens, type of imaging detector, and type of cement all affected the radiopacity threshold for artificial cement excess (P .05). The height of the specimens and the surrounding structures were not statistically significant factors in cement detection. Conclusions: Digital radiography offers better possibilities for visualization of cement excess than conventional radiography. Keywords: cement overhang, digital radiography, luting cement, radiopacity