Factors affecting marginal bone loss around implants and opposing teeth: a CBCT-based retrospective study

This study aimed to investigate the effects of angulation of dental implants and prosthetic/periodontal factors on the marginal bone loss (MBL) of the implant and opposite teeth using cone beam computed tomography (CBCT). The study included 131 previously performed implants in 41 patients. The crown-implant body angles of the implants and the angles between the implant and the long axis of the opposing tooth were measured in the coronal and sagittal directions. The amount and angles of MBL around the implants and teeth were measured. The distal and vestibular MBL of implants in the mandible were higher than those in the maxilla ( p = 0.034, p < 0.01, respectively). MBL in the mesial and distal of implants with low bone density (BD) was higher than that in implants with normal BD ( p < 0.01). The amount of mesial and distal defects was significantly higher in implants with opposing implants than in those with opposing natural teeth ( p < 0.05). Mesial and distal MBL were observed to be higher in the implants with poor crown fit and/or natural teeth with vertical MBL ( p < 0.05). In the sagittal plane, there was a negative correlation between implant-opposing tooth angle and implant mesial, vestibular, and lingual defect amounts, opposing tooth lingual, mesial and distal defect amounts ( p < 0.05). The site of implantation, BD, crown fit, and the presence of vertical MBL in the remaining teeth seem to affect MBL. In addition, the angular relationship of the implants with the opposing teeth can affect the MBL in both the implant and the opposing teeth.