Osteonecrosis of the jaw unrelated to medication or radiotherapy

A Narrative Review of Osteonecrosis of the Jaw: What a Clinician Should Know

Medication-related osteonecrosis of the jaw (MRONJ) is an uncommon complication of antiresorptive therapy (ART) in patients receiving higher and more frequent doses of osteoclast inhibitors. The jaws are the most common site, as they have high bone turnover. The oral structures are exposed to various types of stresses, like mastication and dental diseases, which lead to microtrauma and increased bone remodeling. The hallmark feature of MRONJ is the area of exposed, necrotic, nonhealing, asymptomatic bone for more than eight weeks. Objective signs are pain in the jaw and oral cavity, loose teeth, gingival swelling, ulceration, soft tissue infection, and paresthesia in the trigeminal nerve branches' territory. Clinically, the MRONJ has been defined in four stages, from stage 0 to stage 3. Close coordination between the dentist and oncologist is critical for optimal treatment. Conservative management should be preferred over surgical management. There is significant underreporting and misdiagnosis of MRONJ cases in regular clinical practice. There needs to be more awareness among treating physicians about this sporadic complication of bisphosphonate therapy. This narrative review has given a detailed insight into the subject, starting with etiology, pathogenesis, incidence, clinical presentation, workup, staging, and various management strategies. The review article focuses mainly on practical aspects of MRONJ, which every clinician dealing with the disease must know. With a better awareness of this potential complication, healthcare practitioners dealing with at-risk patients can better diagnose, prevent, address, and provide necessary care.

Osteonecrosis of the Jaw

Osteonecrosis of the jaw is a condition in which bone cells die due to various causes. It is classified as drug-induced jaw osteonecrosis, osteoradionecrosis, traumatic, non-traumatic, and spontaneous osteonecrosis. Antiresorptive or antiangiogenic drugs cause drug-induced osteonecrosis. The combination of medications, microbial contamination, and local trauma induces this condition. Osteoradionecrosis is a severe radiation therapy side effect that can affect people with head and neck cancer. It is described as an exposed bone area that does not heal for longer than three months after the end of radiation treatment with the absence of any indications of an original tumor, recurrence, or metastasis. Trauma (tooth extraction), tumor site, radiation dose that the patient receives, the area of the bone which is irradiated, oral hygiene, and other factors are risk factors for the development of osteonecrosis. Less frequently, osteonecrosis can also be induced by non-traumatic and traumatic causes. Non-traumatic osteonecrosis is brought on by infections, acquired and congenital disorders, as well as the impact of chemicals. Traumatic osteonecrosis is brought on by thermal, mechanical, or chemical damage. The treatment of osteonecrosis can be conservative, which aims to be beneficial for the patient's quality of life, and surgical, which involves debridement of the necrotic bone.

Actinomyces sp. Presence in the Bone Specimens of Patients with Osteonecrosis of the Jaw: The Histopathological Analysis and Clinical Implication

Medication-related osteonecrosis of the jaw (MRONJ) and osteoradionecrosis (ORN) are two similar bone pathologies in the jaw with different aetiologies. Actinomycosis is a relatively rare oral infection caused by the Gram-positive anaerobe Actinomyces sp. that normally colonizes the oral cavity. Actinomycosis is associated with the pathogenesis of both the MRONJ and ORN, as evident in our cases, and not just as a superficial contaminant. The clinical and histopathological aspects of the cases treated in our centre were also reported with a review of the literature. Clinical implication on the treatment of the cases was highlighted in view of the presence of this microorganism.

Osteonecrosis of the Jaws in Patients with Hereditary Thrombophilia/Hypofibrinolysis-From Pathophysiology to Therapeutic Implications

Osteonecrosis of the jaws (ONJ) usually has a clear etiology. Local infection or trauma, radiotherapy and drugs that disrupt the vascular supply or bone turnover in the jaws are its major contributors. The thrombotic occlusion of the bone’s venous outflow that occurs in individuals with hereditary thrombophilia and/or hypofibrinolysis has a less known impact on jaw health and healing capability. Our research provides the most comprehensive, up-to-date and systematized information on the prevalence and significance of hereditary thrombophilia and/or hypofibrinolysis states in ONJ. We found that hereditary prothrombotic abnormalities are common in patients with ONJ refractory to conventional medical and dental treatments. Thrombophilia traits usually coexist with hypofibrinolysis traits. We also found that frequently acquired prothrombotic abnormalities coexist with hereditary ones and enhance their negative effect on the bone. Therefore, we recommend a personalized therapeutic approach that addresses, in particular, the modifiable risk factors of ONJ. Patients will have clear benefits, as they will be relieved of persistent pain and repeated dental procedures.

Radiotherapy-induced bone deterioration is exacerbated in diabetic rats treated with streptozotocin

Following radiotherapy, patients have decreased bone mass and increased risk of fragility fractures. Diabetes mellitus (DM) is also reported to have detrimental effects on bone architecture and quality. However, no clinical or experimental study has systematically characterized the bone phenotype of the diabetic patients following radiotherapy. After one month of streptozotocin injection, three-month-old male rats were subjected to focal radiotherapy (8 Gy, twice, at days 1 and 3), and then bone mass, microarchitecture, and turnover as well as bone cell activities were evaluated at 2 months post-irradiation. Micro-computed tomography results demonstrated that DM rats exhibited greater deterioration in trabecular bone mass and microarchitecture following irradiation compared with the damage to bone structure induced by DM or radiotherapy. The serum biochemical, bone histomorphometric, and gene expression assays revealed that DM combined with radiotherapy showed lower bone formation rate, osteoblast number on bone surface, and expression of osteoblast-related markers (ALP, Runx2, Osx, and Col-1) compared with DM or irradiation alone. DM plus irradiation also caused higher bone resorption rate, osteoclast number on bone surface, and expression of osteoclast-specific markers (TRAP, cathepsin K, and calcitonin receptor) than DM or irradiation treatment alone. Moreover, lower osteocyte survival and higher expression of Sost and DKK1 genes (two negative modulators of Wnt signaling) were observed in rats with combined DM and radiotherapy. Together, these findings revealed a higher deterioration of the diabetic skeleton following radiotherapy, and emphasized the clinical importance of health maintenance.

Cancer Patients at Risk for Medication-Related Osteonecrosis of the Jaw. A Case and Control Study Analyzing Predictors of MRONJ Onset

The goal of this investigation was to identify potential risk factors to predict the onset of medication-related osteonecrosis of the jaw (MRONJ). Through the identification of the multiple variables positively associated to MRONJ, we aim to write a paradigm for integrated MRONJ risk assessment built on the combined analysis of systemic and local risk factors. The characteristics of a cohort of cancer patients treated with zoledronic acid and/or denosumab were investigated; beyond the set of proven risk factors a new potential one, the intake of new molecules for cancer therapy, was addressed. Registered data were included in univariate and multivariate logistic regression analysis in order to individuate significant independent predictors of MRONJ; a propensity score-matching method was performed adjusting by age and sex. Univariate logistic regression analysis showed a significant effect of the parameters number of doses of zoledronic acid and/or denosumab (OR = 1.03; 95% CI = 1.01–1.05; p = 0.008) and chemotherapy (OR = 0.35; 95% CI = 0.17–0.71; p = 0.008). The multiple logistic regression model showed that breast, multiple myeloma, and prostate cancer involved a significantly higher risk compared to lung cancer; a significant effect of the combined variables number of doses of zoledronic acid and/or denosumab (OR = 1.03; 95% CI = 1.01–1.06); p-value = 0.03) and exposure to novel molecule treatment (OR = 34.74; 95% CI = 1.39–868.11; p-value = 0.03) was observed. The results suggest that a risk assessment paradigm is needed for personalized prevention strategies in the light of patient-centered care.

Mycobacterial and Plasmodium ovale-associated destruction of the jaw bones

OBJECTIVES

The project aims were to identify infectious mechanisms responsible for an extreme form of mandibular osteonecrosis and osteomyelitis in West African populations and test the hypothesis that Mycobacterium tuberculosis plays a pivotal role.

MATERIALS AND METHODS

DNA was extracted from mandibular fragments of 9 of 19 patients previously included in a prospective study leading to the mycobacterial hypothesis. Amplified DNAs were used for preparing libraries suitable for next-generation sequencing. For comparison of the whole-genome sequencing data of the 9 patients with DNAs of both microbiota and human tissues, DIAMOND v0.9.26 was used to align sequencing reads to NCBI-nr database and MEGAN 6 for taxonomy binning and identification of Mycobacterium tuberculosis strains.

RESULTS

The data show that mandibular bone fragments of all 9 patients not only contain Homo sapiens and Mycobacterium tuberculosis DNAs; they also contain DNAs of Plasmodium ovale wallikeri, Staphylococcus aureus, Staphylococcus hominis, and Prevotella P3-120/intermedia; as well as large numbers of DNAs from other infectious components.

CONCLUSIONS

The data obtained provide direct evidence to support the conclusion that combinations of Mycobacterium tuberculosis, Plasmodium ovale wallikeri, and other oral bacteria are involved in this particular type of mandibular destruction in West African individuals of many ages.

Osteomyelitis, osteoradionecrosis, or medication-related osteonecrosis of the jaws? Can CBCT enhance radiographic diagnosis?

OBJECTIVE

To attempt defining differential radiographic diagnostic characteristics for osteonecrotic lesions using 2D as opposed to 3D images.

MATERIALS AND METHODS

This was a cross-sectional study. Subjects presenting mandibular osteonecrotic lesions (osteomyelitis, osteoradionecrosis, and medication-related osteonecrosis of the jaws) were selected and compared to a group of age- and gender-matched controls, all having both cone-beam computed tomographic images (CBCT) and panoramic radiographs (PANO). Both imaging modalities (predictor variables) were evaluated by two radiologists that scored lesion presence, eight additional radiological features, and a composite severity index (outcome variables). For each pathologic condition, characteristic features were assessed in PANO and CBCT by the Wilcoxon signed-rank test. Regression tree analysis revealed the predictive value of PANO and CBCT (α = 5%).

RESULTS

Overall, the predictive value of PANO reached 74%, while for CBCT it became 90%. Regarding the composite severity index, CBCT enabled to detect more subtle lesions. Also, CBCT imaging allowed showing more distinct radiographic diagnostic features as compared to PANO imaging, more specifically when distinguishing osteomyelitis from both other lesions.

CONCLUSIONS

Cone-beam computed tomography enabled showing more differences in radiological features between distinct osteonecrosis disease entities. CBCT imaging might be a better contributor for the detection of early lesions and to monitor further pathological developments in the mandible.

Spontaneous oral ulceration with bone sequestration: its relevance in current clinical practice

Oral ulceration associated with bony exposure and sequestration is uncommon and often related to well-recognised conditions. In a small group of patients no obvious aetiological factors can be elucidated, and various terminologies have been utilised to describe these lesions. We report six cases of spontaneous oral ulceration with bone sequestration as a specific entity and review the pertinent literature. We retrospectively reviewed patients presenting in the period 2013-2018. Data collected included demographic details, relevant medical, drug, and radiotherapy history; presentation, investigations, management, and outcome. Six patients with an age range of 49-65 years were identified with spontaneous oral ulceration with bone sequestration in the study period. All were males, and none had any relevant history. Five lesions occurred over the mylohyoid ridge and one was related to a lingual mandibular torus. The most common presentation was a painful ulcer with exposed bone, which had been present for 6 - 12 weeks. Occlusal radiographs demonstrated focal rarefaction in two patients. All were managed conservatively and by removal of the loose sequestrum. Healing occurred successfully in all cases, and this was earlier when the loose sequestrum was removed. Spontaneous oral ulceration with bone sequestration is a distinct lesion that most often presents over the prominence of the mylohyoid ridge. It is currently an uncommon entity (0.02%), but this could well be due to a lack of recognition and under-reporting. It should be considered as a diagnosis only when other causes have been excluded. Lesions heal successfully with conservative management and surgical intervention, and this occurs earlier following removal of the loose sequestrum.

Oral and Dental Abnormalities Caused by a Pediatric Rhabdomyosarcoma Tumor Treatment: A Clinical Case Report

Rhabdomyosarcoma is one of the most common soft-tissue sarcomas in children. The therapy for this condition has evolved significantly over recent decades, as has survival rates. Nevertheless, multiagent chemotherapy, radiation therapy, surgical resection or a combination of these modalities still have to be performed. This case report presents a 16-year-old boy with oral and dental effects after rhabdomyosarcoma treatment, diagnosed at the age of 4 years old. This report highlights the key role of dentists in the clinical management of rhabdomyosarcoma cases before, during and after treatment, and its potential side effects.

Everolimus-induced osteonecrosis of the jaw in the absence of bisphosphonates: a case report

Osteonecrosis of the jaw (ONJ) is a rare, but severe, condition that has traditionally been associated with the use of bisphosphonates. We report what is, to our knowledge, the first case of ONJ secondary to the use of everolimus, in the absence of treatment with bisphosphonates in a 65-year-old man who was given it for immunosuppression after a renal transplant. After 18 months of treatment, he was diagnosed with severe ONJ and underwent radical debridement of the palate and complete dental clearance of the maxilla.

Oral ulceration with bone sequestration: Retrospective study of eight cases and literature review

OBJECTIVE

Oral ulceration with bone sequestration (OUBS) describes a site-specific intraoral ulcer that covers exposed, non-vital bone in patients lacking any etiological factor known to induce osteonecrosis. We aimed to conduct a retrospective study of eight new cases of OUBS and review the literature.

SUBJECTS AND METHODS

This is a retrospective study of OUBS cases, diagnosed and managed during 2007-2017. Inclusion criteria were the presence of oral ulcer with exposed non-vital bone at sites of bone prominence and the absence of any factor known to cause osteonecrosis. The English literature was reviewed on original OUBS cases.

RESULTS

Eight patients (5 males and 3 females, aged 27-75 years) were diagnosed with OUBS during years 2007-2017. Four cases involved the mandibular mylohyoid ridge, one a mandibular anterior exostosis and three the maxillary buccal/palatal exostoses. Exposed bone was removed under local anesthesia, resulting in complete healing in all cases. The literature review yielded 32 OUBS cases in the mandible.

CONCLUSION

Oral ulceration with bone sequestration is a distinct, probably under-reported rather than rare clinical entity that should be regarded the provisional diagnosis in case of an oral ulcer covering exposed, non-vital bone at sites of bone prominence in patients lacking any etiological factor known to induce osteonecrosis.