A comparison of the cone beam computed tomography findings in medication-related osteonecrosis of the jaws related to denosumab versus bisphosphonates: an observational pilot study

Three-dimensional clinical assessment for MRONJ risk in oncologic patients following tooth extractions

OBJECTIVES

To identify clinical and local radiographic predictors for medication-related osteonecrosis of the jaws (MRONJ) by the assessment of pre-operative CBCT images of oncologic patients treated with anti-resorptive drugs (ARDs) undergoing tooth extractions.

METHODS

This retrospective, longitudinal, case-control study included clinical and imaging data of 97 patients, divided into study and control group. Patients in the study group (n = 47; 87 tooth extractions) had received at least one dose of ARD, undergone tooth extraction(s), and had a pre-operative CBCT. An age-, gender-, and tooth extraction-matched control group (n = 50; 106 tooth extractions) was selected. Three calibrated, blinded, and independent examiners evaluated each tooth extraction site. Statistical analysis used χ2/Fisher's exact/Mann-Whitney U test to contrast control and study group, ARD type used, and sites with or without MRONJ development. p-value ≤ 0.05 was considered significant.

RESULTS

From the study group, 15 patients (32%) and 33 sites (38%) developed MRONJ after tooth extraction. When controls were compared to study sites, the latter showed significantly more thickening of the lamina dura, widened periodontal ligament space, osteosclerosis, osteolysis, and sequestrum formation. In the study group, MRONJ risk significantly increased in patients who had multiple tooth extractions, were smokers, and had shorter drug holidays. Periosteal reaction and sequestrum formation may indicate latent MRONJ lesions. Additionally, patients given bisphosphonates showed considerably more osteosclerosis than those given denosumab.

CONCLUSIONS

Periosteal reaction and sequestrum formation are suspected to be pre-clinical MRONJ lesions. Furthermore, ARD induced bony changes and radiographic variations between ARD types were seen.

Risk comparison of osteonecrosis of the jaw in osteoporotic patients treated with bisphosphonates vs. denosumab: a multi-institutional retrospective cohort study in Taiwan

In this multi-institutional retrospective cohort study, we compared the long-term risk of osteonecrosis of the jaw following the use of denosumab vs. bisphosphonates in osteoporotic patients. After 2-year use, the likelihood of osteonecrosis of the jaw is lower with denosumab compared to bisphosphonates, and the difference increases with time.

PURPOSE

To compare the long-term risk of osteonecrosis of the jaw (ONJ) between osteoporotic patients treated with bisphosphonates (BPs) and denosumab.

METHODS

This multi-institutional retrospective cohort study included patients aged > 40 years with osteoporosis between January 2010 and December 2018. Patients who met the eligibility criteria were divided into BPs and denosumab groups by propensity score matching (PSM). The risk of ONJ of denosumab vs. BPs was estimated using a Cox proportional hazards model and was described by the cumulative incidence rate using the Kaplan-Meier method.

RESULTS

A total of 84,102 patients with osteoporosis were enrolled, among whom, 8962 were eligible for inclusion based on their first-line drug use (denosumab, n = 3,823; BPs, n = 5,139). Following PCM matching (1:1), the BPs and denosumab groups included 3665 patients each. The incidence density of ONJ in the denosumab and BPs matching groups was 1.47 vs. 2.49 events (per 1000 person-years), respectively. The hazard ratio of ONJ in the denosumab vs. BPs group was estimated as 0.581 (95% confidence interval: 0.33-1.04, p = 0.07). The cumulative incidence rates of ONJ in both groups were similar for the first and second years of drug use (p = 0.062), but significantly different from the third year onwards (p = 0.022). The severity of ONJ was not significantly different between the two groups.

CONCLUSION

In osteoporotic patients, after 2 years of use, the likelihood of ONJ being induced by denosumab is lower than that of BPs, and the difference increases with time.

Medication-related osteonecrosis of the jaw without osteolysis on computed tomography: a retrospective and observational study

Medication-related osteonecrosis of the jaw (MRONJ) is a refractory osteonecrosis caused by antiresorptive agents such as bisphosphonate and denosumab (DMB). In MRONJ surgery, computed tomography (CT) is generally used to determine the extent of bone resection. However, in some recent MRONJ cases, no abnormal findings were detected on CT. Therefore, we aimed to clarify the characteristics of MRONJ without osteolysis. This retrospective and observational study included 18 patients diagnosed with MRONJ between October 2020 and October 2022 at Department of Dentistry and Oral Surgery, Kansai Medical University Medical Center. In four of 18 patients with MRONJ, no abnormal findings such as osteolysis, separation of sequestrum, and periosteal reaction were observed on CT images at the first visit. All four patients with non-osteolytic MRONJ had malignant tumors and received high-dose DMB, and in the four patients there were no preceding dental infections such as apical lesions or periodontal disease and the trigger of MRONJ was unknown. Surgery was performed in three of the four patients. The extent of bone resection was determined using magnetic resonance imaging and intraoperative gross findings. In the future, it is necessary to establish a method for diagnosing non osteolytic MRONJ and determining the extent of bone resection.

Multiple idiopathic external cervical root resorption in patient treated continuously with denosumab: a case report

Background

External root resorption is an irreversible loss of dental hard tissue as a result of odontoclastic action. Multiple external cervical root resorptions in permanent teeth are rare. The exact cause of external cervical root resorption is unclear. It is currently well established that RANK/RANKL signaling is essential for osteoclastogenesis and osteoclast-mediated bone resorption. Denosumab is an anti-RANKL antibody used for the treatment of postmenopausal osteoporosis. RANK/RANKL pathway suppression by denosumab is expected to suppress the activity of clastic cells responsible for hard tissue resorption involving both osteoclasts and odontoclasts.

Case presentation

This case report demonstrates aggressive and generalized idiopathic external cervical root resorption that started and advanced during ongoing antiresorptive therapy with the human monoclonal RANKL-blocking antibody denosumab without discontinuation of therapy in a 74-year-old female patient treated for postmenopausal osteoporosis. The extent of resorptive defects was too large and progressively led to fractures of the teeth. The number of teeth involved and the extend of destruction excluded conservative treatment. The affected teeth had to be extracted for functional prosthetic reconstruction.

Conclusions

This finding suggests that treatment with denosumab may be associated with severe and aggressive odontoclastic resorption of multiple dental roots despite an adequate inhibitory effect on osteoclasts in the treatment of osteoporosis. The RANKL-independent pathways of clastic cell formation are likely to be involved in this pathological process.

Risk of Osteonecrosis of the Jaw Under Denosumab Compared to Bisphosphonates in Patients With Osteoporosis

Osteonecrosis of the jaw (ONJ) is a rare but serious adverse event associated with antiresorptive treatment. There is little evidence regarding the incidence of ONJ among patients with osteoporosis who are treated with denosumab versus bisphosphonates (BPs). The aim of this study was to determine the risk of ONJ in a real-world population. Subjects who underwent at least one dual-energy X-ray absorptiometry (DXA) examination were included in the osteoporosis register of the Swiss Society of Rheumatology between January 1, 2015, and September 30, 2019. Statistical analyses included incidence rates, rate ratios, and hazard ratios for ONJ, considering sequential therapies and drug holidays as covariates. Among 9956 registered patients, 3068 (89% female, median age 69 years [63 to 76]) were treated with BPs or denosumab for a cumulative duration of 11,101 and 4236 patient-years, respectively. Seventeen cases of ONJ were identified: 12 in patients receiving denosumab at the time of ONJ diagnosis and 5 in patients receiving oral or intravenous BP therapy. The diagnosis of ONJ was confirmed by independent and blinded maxillofacial surgeons, using the American Association of Oral and Maxillofacial Surgeons case definition of ONJ. The incidence of ONJ per 10,000 observed patient-years was 28.3 in patients receiving denosumab and 4.5 in patients with BP-associated ONJ, yielding a rate ratio of 6.3 (95% confidence interval [CI] 2.1 to 22.8), p < 0.001. Nine of 12 patients who developed ONJ during denosumab treatment had been pretreated with BPs, but none of the 5 patients with BP-related ONJ had previously received denosumab. The risk of ONJ was higher in patients receiving denosumab therapy compared with BPs (hazard ratio 3.49, 95% CI 1.16 to 10.47, p = 0.026). Previous BP therapy before switching to denosumab may be an additional risk factor for ONJ development. © 2021 American Society for Bone and Mineral Research (ASBMR).

A Comparison of the Clinical and Radiological Extent of Denosumab (Xgeva®) Related Osteonecrosis of the Jaw: A Retrospective Study

Medication-related osteonecrosis of the jaw (MRONJ) is a severe side effect of antiresorptive medication. The aim of this study was to evaluate the incidence of denosumab-related osteonecrosis of the jaw and to compare the clinical and radiological extent of osteonecrosis. A retrospective study of patients who received Xgeva^® at the Institut de Cancérologie de Lorraine (ICL) was performed. Patients for whom clinical and radiological (CBCT) data were available were divided into two groups: “exposed” for patients with bone exposure and “fistula” when only a fistula through which the bone could be probed was observed. The difference between clinical and radiological extent was assessed. The p-value was set at 0.05, and a total of 246 patients were included. The cumulative incidence of osteonecrosis was 0.9% at 6 months, 7% at 12 months, and 15% from 24 months. The clinical extent of MRONJ was significantly less than their radiological extent: in the “exposed” group, 17 areas (45%) were less extensive clinically than radiologically (p < 0.001) and respectively 6 (67%) for the “fistula” group (p < 0.031). It would seem that a CBCT is essential to know the real extent of MRONJ. Thus, it would seem interesting to systematically perform a CBCT during the diagnosis of MRONJ, exploring the entire affected dental arch.

Quantitative Segmentation Analysis of the Radiological Changes by Using ITK-SNAP: Risk Assessment of the Severity and Recurrence of Medication-related Osteonecrosis of the Jaw

Background and purpose: Medication-related osteonecrosis of the jaw (MRONJ) severely impairs patients' quality of life and is remarkably refractory to treatment. There are lots of studies about identification of the radiographic features of MRONJ, yet reports about quantitative radiographic analysis for the risk assessment of the severity and recurrence of MRONJ are rarely heard. The aim of this study was to investigate the volumes of osteolytic lesions and radiodensity values of osteosclerotic lesions in MRONJ patients by using ITK-SNAP for severity prediction and prognosis evaluation. Materials and methods: Of 78 MRONJ patients (78 lesions) involved in this retrospective study, 53 were presented as osteolytic lesions and 25 were presented as osteosclerotic changes alone. Comprehensive CBCT images, demographics and clinical data of patients were investigated. The volumetric analysis and radiodensity measurement were performed by ITK-SNAP. SPSS 25.0 were used for statistical analysis. Results: The osteolytic lesion volumes in MRONJ patients receiving intravenous bisphosphonates (P=0.004) and patients without osteoporosis (P=0.027) were significantly large. No significant correlation between the volumes and bisphosphonates duration was found (P=0.094). The radiodensity values of osteosclerotic lesions was significantly correlated with bisphosphonates duration (P=0.040). The surrounding area of post-surgical lesions in MRONJ patients with recurrence showed significantly great radiodensity values (P=0.025). No significant correlation between the radiodensity values and the transformation from osteosclerotic lesions to osteolytic lesions was observed (P=0.507). Conclusion: MRONJ patients receiving intravenous bisphosphonates develop into large volumes of osteolytic lesions more easily. Long-term bisphosphonates duration is possibly related with higher bone density of osteosclerotic lesions, while higher density is not associated with the transformation from osteosclerotic lesions to osteolytic lesions. A rise of bone mineral density nearby post-surgical lesions is probably a predictor for MRONJ recurrence.

Bisphosphonate application and volumetric effects on MRONJ lesions

The purpose of this investigation was to analyze the volume of medication-related osteonecrosis of the jaw (MRONJ) lesions by semi-automatic segmentation of cone-beam computed tomography images, and correlate the results with the underlying diseases and applied medication. MRONJ lesions detected in cone-beam computed tomography images were assessed. The open-source software ITK-Snap enabled volumetric measurements of MRONJ lesions based on semi-automatic segmentation. Results were analyzed according to necrosis volume, localization, and gender. In addition, the underlying disease and the type of application of antiresorptive medication were investigated. Cone-beam computed tomography images of 66 patients were studied. 34 male and 32 female patients were included, with ages ranging from 50 to 93 years at the time of diagnosis. The mean volume was 993.24 ± 620.94 mm³: 484.73 ± 230.97 mm³ for the upper jaw and 1084.04 ± 625.74 mm³ for the lower jaw. The results indicated statistically significant differences between lesions of the upper and lower jaw, regardless of gender (p = 0.003). The analysis of differences between males and females did not show any significant results (p = 0.464), although males presented slightly larger lesions than females. With regard to the underlying disease, patients with osteoporosis presented larger volumes, whereas patients with malignant tumors presented smaller volumes. Nevertheless, no statistically significant differences according to the underlying disease (p = 0.313) were detected. However, patients with intravenous (iv) application showed statistically significantly larger lesions than patients who underwent oral or subcutaneous (s.c.) applications (p = 0.004). It seems that the osteonecrosis volume correlates with the applied antiresorptive agents. Larger MRONJ lesions should be expected in patients who receive intravenous antiresorptive therapy.

Do various imaging modalities provide potential early detection and diagnosis of medication-related osteonecrosis of the jaw? A review

OBJECTIVE

Patients with medication-related osteonecrosis of the jaw (MRONJ) often visit their dentists at advanced stages and subsequently require treatments that greatly affect quality of life. Currently, no clear diagnostic criteria exist to assess MRONJ, and the definitive diagnosis solely relies on clinical bone exposure. This ambiguity leads to a diagnostic delay, complications, and unnecessary burden. This article aims to identify imaging modalities' usage and findings of MRONJ to provide possible approaches for early detection.

METHODS

Literature searches were conducted using PubMed, Web of Science, Scopus, and Cochrane Library to review all diagnostic imaging modalities for MRONJ.

RESULTS

Panoramic radiography offers a fundamental understanding of the lesions. Imaging findings were comparable between non-exposed and exposed MRONJ, showing osteolysis, osteosclerosis, and thickened lamina dura. Mandibular cortex index Class II could be a potential early MRONJ indicator. While three-dimensional modalities, CT and CBCT, were able to show more features unique to MRONJ such as a solid type periosteal reaction, buccal predominance of cortical perforation, and bone-within-bone appearance. MRI signal intensities of vital bones are hypointense on T₁WI and hyperintense on T₂WI and STIR when necrotic bone shows hypointensity on all T₁WI, T₂WI, and STIR. Functional imaging is the most sensitive method but is usually performed in metastasis detection rather than being a diagnostic tool for early MRONJ.

CONCLUSION

Currently, MRONJ-specific imaging features cannot be firmly established. However, the current data are valuable as it may lead to a more efficient diagnostic procedure along with a more suitable selection of imaging modalities.

Several issues regarding the diagnostic imaging of medication-related osteonecrosis of the jaw

This review presents an overview of some diagnostic imaging-related issues regarding medication-related osteonecrosis of the jaws (MRONJ), including imaging signs that can predict MRONJ in patients taking antiresorptive drugs, the early imaging features of MRONJ, the relationship between the presence or absence of bone exposure and imaging features, and differences in imaging features by stage, between advanced MRONJ and conventional osteomyelitis, between oncologic and osteoporotic patients with MRONJ, and depending on the type of medication, method of administration, and duration of medication. The early diagnosis of MRONJ can be made by the presence of subtle imaging changes such as thickening of the lamina dura or cortical bone, not by the presence of bone exposure. Most of the imaging features are relatively non-specific, and each patient's clinical findings and history should be referenced. Oral and maxillofacial radiologists and dentists should closely monitor plain radiographs of patients taking antiresorptive/antiangiogenic drugs.