Differences between bisphosphonate-related and denosumab-related osteonecrosis of the jaws: a systematic review.

OBJECTIVE: Bisphosphonates and denosumab are both antiresorptive medications, each with their own mechanism of action; yet both may result in the same adverse effect: medication-related osteonecrosis of the jaw (ONJ). The present systematic review aims to answer the following question: "Are bisphosphonate-related ONJ and denosumab-related ONJ any different, regarding clinical and imaging aspects?" METHODS: This review followed the Joanna Briggs Review's Manual, and the searches were performed on PubMed, Cochrane, Scopus, Web of Science, and Lilacs databases and on the grey literature (ProQuest, Open Grey, and Google Scholar). RESULTS: The searches resulted in 7535 articles that were critically assessed. Based on the selection criteria, seven studies were included in the review: five cross-sectional studies and two randomized clinical trials. A total of 7755 patients composed the final population. An increase in bone sequestra, cortical bone lysis, and bone density was observed in bisphosphonate-related ONJ, while larger bone sequestra, more frequent periosteal reactions, and mandibular canal enhancement were noted in denosumab-related ONJ. CONCLUSION: This systematic review demonstrated that the imaging characteristics of bisphosphonate-related and denosumab-related ONJ are not similar. Although clinically similar conditions, they were found to be radiographically distinct. More studies are necessary to further elucidate these differences.

Early bony changes associated with bisphosphonate-related osteonecrosis of the jaws in rats: A longitudinal in vivo study.

OBJECTIVE: To evaluate early bony changes in an animal model of Medication-Related Osteonecrosis of the Jaw (MRONJ) at the side of the local trauma and at the contralateral side, comparing with a control group. Bony changes were evaluated by Microcomputed Tomography (MicroCT) at three times points: at baseline (T0), after drug administration (T1) and after dental extraction (T2). DESIGN: Two groups were compared: the experimental group in which zoledronic acid (ZA) was administered (17 rats) and the control group (13 rats). Dental extractions of the lower left first molars were performed in all animals. The left side was considered as the supposed affected area in the ZA group, and the right side was considered as the unaffected area. In these areas, the following structural microtomographic bone parameters were calculated: Bone Mineral Density (BMD), Trabecular Thickness (Tb.Th), and Bone Volume Proportion (BV/TV). The comparison of quantitative bone parameters among the different sides and experimental phases of both studied groups were performed by ANOVA-factorial. RESULTS: None of the animals of the control group developed MRONJ. In the ZA group, 76% presented bone exposure. From T0 to T1, Tb.Th and BV/TV increased, and in T2, the mean values were higher in ZA group than in the control group. BMD increased throughout the different phases of both groups. CONCLUSIONS: Structural bony changes occurred in the ZA group at both mandibular sides before the dental extraction (T1). Tb.Th and BV/TV should be further investigated as potential early bone markers of MRONJ.

Cone-beam computed tomography and microtomography for alveolar bone measurements.

PURPOSE: To compare cone-beam computed tomography (CBCT) and microtomography (micro-CT) for alveolar bone measurements. METHODS: Forty teeth and alveolar bone blocks of five pigs were scanned on a micro-CT with a 9.05 µm pixel size, and on a CBCT device at 0.125 mm voxel size. One height and four thickness measurements were performed twice in standardized slices by two radiologists to verify reliability. Agreement between imaging methods was assessed by correlation coefficients, Bland-Altman plots, and the difference was tested by a Wilcoxon signed-rank test. RESULTS: Regarding intra- and interobserver agreements, all bone measurements presented excellent precision values for micro-CT, but interobserver agreement for CBCT presented good to moderate values. Bone height differed about 0.3 mm, but no statistically significant differences were found for the bone thickness measurements. CONCLUSION: CBCT underestimated bone height. No statistically significant differences were found for bone thickness. Regions of thin bone tissue may not be visualized on CBCT images. There are risks of underestimating bone measurements with CBCT and assuming bone loss that does not exist clinically. Although the difference of the bone height measurement was small, the clinical relevance must be analyzed on how to interpret CBCT.