Dental implants as risk factors for patients with medication-related osteonecrosis of the jaws (MRONJ).

An increasing number of patients with medication-related osteonecrosis of the jaws (MRONJ) has recently been reported. It is still being debated whether the presence or placement of dental implants can lead to MRONJ, so the aim of this study was to find out whether dental implants are a risk factor for MRONJ. From January 2003-January 2019 180 patients with MRONJ were seen at the Leiden University Medical Center. Luxating moments for the onset of MRONJ were calculated retrospectively. We collected clinical data and details of antiresorptive medication and found 22 patients with both dental implants and MRONJ. In 18 patients the implants were in the region of the MRONJ and they were included in this study, 14 who had had implants before using antiresorptive drugs and four who had had antiresorptive drugs before or at the time that the implants were placed. The median times between the placement of implants and the diagnosis of MRONJ in these two groups were 24 months and 6 months, respectively. Among the 47 implants, 30 were located in the necrotic region, and all 30 were either lost spontaneously or had to be removed during treatment of MRONJ. Our results show an increased risk for developing MRONJ in patients with dental implants. Both peri-implantitis around previously placed implants, and insertion of dental implants, are risk factors. Prevention of peri-implantitis and caution when inserting dental implants in patients who take antiresorptive medication are therefore important.

Density of the mandibular ramus (cancellous:cortical bone volume ratio) as a predictor of the lingual fracture pattern in bilateral sagittal split osteotomy.

The aim of this retrospective cohort study was to evaluate the relative amount of cancellous bone in the mandibular ramus as a predictor of lingual fracture patterns after bilateral sagittal split osteotomy (BSSO). The study including 78 consecutive patients (156 osteotomy sites). In preoperative cone-beam computed tomographic (CT) scans, the volumes of cancellous and cortical bone in the BSSO surgical field were estimated. Patients were divided into two groups based on the cancellous:cortical bone ratio. We studied postoperative cone-beam CT scans for lingual fracture lines and subcategorised them according to the lingual split scale (LSS). Generalised linear mixed models (GLMM) were estimated to evaluate the association between the cancellous:cortical bone ratio and the lingual fracture pattern. There was a significant association between the cancellous:cortical bone ratio of the mandibular angle and the lingual fracture pattern after BSSO. Mandibular angles with a relatively small amount of cancellous bone showed significantly more LSS3 fracture lines (OR=1.990, 95%CI 1.043 to 3.796, p=0.043). These mandibular angles also showed more unfavourable fractures (LSS4), although this was not significant (OR=2.352, 95%CI 0.748 to 7.392, p=0.143). The relative amount of cancellous bone in the mandibular angle is significantly associated with the lingual fracture line after BSSO.