Cumulative incidence and risk factors for medication-related osteonecrosis of the jaw during long-term prostate cancer management.

Bone-modifying agents (BMA) are extensively used in treating patients with prostate cancer with bone metastases. However, this increases the risk of medication-related osteonecrosis of the jaw (MRONJ). The safety of long-term BMA administration in clinical practice remains unclear. We aimed to determine the cumulative incidence and risk factors of MRONJ. One hundred and seventy-nine patients with prostate cancer with bone metastases treated with BMA at our institution since 2008 were included in this study. Twenty-seven patients (15%) had MRONJ during the follow-up period (median, 19 months; interquartile range, 9-43 months). The 2-year, 5-year, and 10-year cumulative MRONJ incidence rates were 18%, 27%, and 61%, respectively. Multivariate analysis identified denosumab use as a risk factor for MRONJ, compared with zoledronic acid use (HR 4.64, 95% CI 1.93-11.1). Additionally, BMA use at longer than one-month intervals was associated with a lower risk of MRONJ (HR 0.08, 95% CI 0.01-0.64). Furthermore, six or more bone metastases (HR 3.65, 95% CI 1.13-11.7) and diabetes mellitus (HR 5.07, 95% CI 1.68-15.2) were risk factors for stage 2 or more severe MRONJ. MRONJ should be considered during long-term BMA administration in prostate cancer patients with bone metastases.

Epidemiology, etiopathogenesis, and management of MRONJ: A European multicenter study.

INTRODUCTION: The purpose of this European multicenter study was to describe the general characteristics and risk factors of MRONJ lesions as well as their clinical diagnosis and management at different European Oral and Maxillofacial Surgery centers, in order to minimize selections biases and provide information about the epidemiology, etiopathogenesis, and the current trends in the treatment of MRONJ across Europe. MATERIALS AND METHODS: The following data were registered for each patient: gender; age at MRONJ diagnosis; past medical history; indication for antiresorptive or antiangiogenic therapy; type of antiresorptive medication; local risk factor for MRONJ; MRONJ Stage; anatomic location and symptoms; treatment; surgical complications; recurrence. RESULTS: A total of 537 patients (375 females, 162 males) with MRONJ were included. Statistically significant associations were found between patients with metastatic bone disease and recurrences (P < 0.0005) and between advanced MRONJ stages (stages 2 and 3) and recurrences (P < 0.005). Statistically significant associations were also found between male gender and recurrences (P < 0.05), and between MRONJ maxillary sites and recurrences (P < 0.0000005). CONCLUSIONS: A longer mean duration of antiresorptive medications before MRONJ onset was observed in patients affected by osteoporosis, whereas a shorter mean duration was observed in all metastatic bone cancer patients, and in particular in those affected by prostate cancer with bone metastases or multiple myeloma. Surgery plays an important role for the management of MRONJ lesions.

Key insights into antiresorptive drug use and osteonecrosis in osteoporotic patients undergoing tooth extractions: A clinical and CBCT assessment.

This study investigates the effects of antiresorptive drugs and risk factors for medication-related osteonecrosis of the jaws in osteoporotic patients undergoing tooth extraction. Among the findings, antiresorptive-treated patients had thicker lamina dura and longer healing times. Additionally, corticosteroid intake and multi-rooted teeth carried a higher osteonecrosis risk. Bone sequestrum indicated osteonecrosis. PURPOSE: To describe the effects of antiresorptive drugs (ARD) in the maxilla and mandible and risk factors for medication-related osteonecrosis of the jaws (MRONJ) in osteoporotic patients undergoing tooth extractions using clinical data and cone beam computed tomography (CBCT). METHODS: This retrospective cohort study collected clinical and CBCT data from 176 patients. The study group (n = 78; 224 extractions) received ARD treatment, underwent tooth extraction, and had a pre-operative CBCT. Additionally, age-, sex-, and tooth-matched controls were selected (n = 98; 227 extractions). Radiographic examinations were performed independently by three calibrated examiners. Statistical analysis included Chi-square, Fisher's exact, Mann-Whitney U, and t-tests to contrast clinical and radiographic data between study and control, MRONJ + and MRONJ - , and bisphosphonate and denosumab patients/sites. Significance was set at p ≤ 0.05. RESULTS: From the study group, 4 patients (5%) and 5 sites (2%) developed MRONJ after tooth extraction. ARD-treated patients exhibited significantly more thickening of the lamina dura and a longer average mucosal healing time (4.4 weeks) than controls (2.6 weeks). In the study group, MRONJ risk significantly increased with corticosteroid intake and in multi-rooted teeth. No significant differences between bisphosphonates and denosumab use were seen in the tomographic features (p > 0.05). Lastly, bone sequestrum was exclusively observed in osteoporotic patients, who exhibited post-operative exposed bone or histological evidence of osteonecrosis. CONCLUSION: Osteoporotic patients under ARD may exhibit thickening of the lamina dura and prolonged post-operative healing. Among these patients, multi-rooted teeth are at higher risk for MRONJ than single-rooted teeth. Sequester formation is a radiographic indicator of osteonecrosis.

The assessment of halitosis with a new screening tool in medication-related osteonecrosis of the jaw.

OBJECTIVES: This study aimed to identify the levels of halitosis in patients with Medication-related osteonecrosis of the jaw (MRONJ) and osteoporosis and to suggest a new MRONJ screening method using halitosis measurement. MATERIALS AND METHODS: From October 2019 to April 2023, participants aged 19 years or older without periodontal disease were selected. Seventy-five participants, 25 in each group, were divided into an MRONJ group, an osteoporosis group without MRONJ, and a control group without osteoporosis and not taking osteoporosis drugs or antibiotics. Each participant underwent halitosis assessment twice using an exhaled breath analyzer to measure halitosis twice by blowing a straw for 1 min. Measured concentrations of hydrogen, hydrogen sulfide, and methyl mercaptan were compared between groups. RESULTS: Data from 22 patients in the MRONJ group, 25 in the osteoporosis group, and 25 in the control group were analyzed. The concentrations of hydrogen sulfide and methyl mercaptan were significantly higher in the MRONJ group than in the other groups, but the concentrations of hydrogen did not differ between the groups. When comparing the concentrations of hydrogen sulfide and methyl mercaptan in osteoporosis patients and solid cancer patients in the MRONJ group, there was a significant difference in hydrogen sulfide concentration, but there was no significant difference in methyl mercaptan. CONCLUSIONS: Quantifying the level of halitosis can be used to screen for MRONJ in patients taking bisphosphonates, such as patients with osteoporosis, prostate cancer, and breast cancer. CLINICAL RELEVANCE: MRONJ is accompanied by bad breath, and the concentrations of hydrogen sulfide and methyl mercaptan are associated with MRONJ.

Rodents as an animal model for studying tooth extraction-related medication-related osteonecrosis of the jaw: assessment of outcomes.

OBJECTIVE: To assess the outcomes of several rodent animal models for studying tooth extraction-related medication-related osteonecrosis of the jaw (MRONJ). DESIGN: After a search of the databases, 2004 articles were located, and 118 corroborated the inclusion factors (in vivo studies in rodents evaluating tooth extraction as a risk factor for the development of MRONJ). RESULTS: Numerous studies attempting to establish an optimal protocol to induce MRONJ were found. Zoledronic acid (ZA) was the most used drug, followed by alendronate (ALN). Even when ZA did not lead to the development of MRONJ, its effect compromised the homeostasis of the bone and soft tissue. The association of other risk factors (dexamethasone, diabetes, and tooth-related inflammatory dental disease) besides tooth extraction also played a role in the development of MRONJ. In addition, studies demonstrated a relationship between cumulative dose and MRONJ. CONCLUSIONS: Both ZA and ALN can lead to MRONJ in rodents when equivalent human doses (in osteoporosis or cancer treatment) are used. Local oral risk factors and tooth-related inflammatory dental disease increase the incidence of MRONJ in a tooth extraction-related rodent model.

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.

Establishment and assessment of rodent models of medication-related osteonecrosis of the jaw (MRONJ).

Medication-related osteonecrosis of the jaw (MRONJ) is primarily associated with administering antiresorptive or antiangiogenic drugs. Despite significant research on MRONJ, its pathogenesis and effective treatments are still not fully understood. Animal models can be used to simulate the pathophysiological features of MRONJ, serving as standardized in vivo experimental platforms to explore the pathogenesis and therapies of MRONJ. Rodent models exhibit excellent effectiveness and high reproducibility in mimicking human MRONJ, but classical methods cannot achieve a complete replica of the pathogenesis of MRONJ. Modified rodent models have been reported with improvements for better mimicking of MRONJ onset in clinic. This review summarizes representative classical and modified rodent models of MRONJ created through various combinations of systemic drug induction and local stimulation and discusses their effectiveness and efficiency. Currently, there is a lack of a unified assessment system for MRONJ models, which hinders a standard definition of MRONJ-like lesions in rodents. Therefore, this review comprehensively summarizes assessment systems based on published peer-review articles, including new approaches in gross observation, histological assessments, radiographic assessments, and serological assessments. This review can serve as a reference for model establishment and evaluation in future preclinical studies on MRONJ.

One changing and challenging scenario: the treatment of cancer patients with bone metastases by bisphosphonates and denosumab, the cost-benefit evaluation of different options, and the risk of medication-related osteonecrosis of the jaw (MRONJ).

Antiresorptive drugs (bisphosphonates and denosumab) have become the cornerstone of medical supportive treatment of bone metastases in solid cancer patients. In the beginning, the choice of available antiresorptive agents was limited to bisphosphonates and the treatment options restricted principally to monthly pamidronate and monthly zoledronic acid. Introduction of new antiresorptive therapies (monthly denosumab) and schedules (zoledronic acid every 3 months, upfront or after initial period of monthly infusion) in the last decade increased the range of available options, thus challenging treatment decision making. Direct and indirect costs of very different treatment options are difficult to interpret in a global cost-benefit analysis. In addition, awareness of the increased risk of medication-related osteonecrosis of the jaw (MRONJ) in bone metastatic cancer patients receiving long-term antiresorptive medications is likely to influence therapy choice in the real-life scenario. We discuss the possible threat of MRONJ risk underestimation and the need for long-term risk stratification of patients based on actuarial data, the role of bisphosphonates and denosumab in that scenario, and the emerging role of surgical therapy to successfully cure MRONJ, in the light of the improved quality of life and survival of patients with bone metastases from solid cancers.

Medication Management of Selected Pathological Jaw Lesions.

Most jaw lesions are treated surgically. Areas of abnormal proliferation or destruction in bone are commonly treated by regional curettage, excision, or resection. However, surgery is invasive and leaves a defect where the lesion was removed. Surgical trauma to adjacent healthy tissue, including vital neurovascular bundles is often unavoidable, and can be especially traumatizing to the pediatric patient. Select jaw lesions with well-studied nonsurgical pharmaceutical treatments are presented here.

Quantitative assessment of mandibular bone marrow using computed tomography texture analysis for detect stage 0 medication-related osteonecrosis of the jaw.

PURPOSE: Medication-related osteonecrosis of the jaw (MRONJ) is a serious complication of treatment with bisphosphonates or antiangiogenic inhibitors. MRONJ has four stages (0-3); however, stage 0 MRONJ is difficult to detect using computed tomography (CT). This study aimed to quantitatively assess the mandibular bone marrow using texture analysis to detect stage 0 MRONJ from CT images. METHODS: This retrospective study included 25 patients with stage 0 MRONJ who had a history of treatment with bisphosphonates and underwent CT and magnetic resonance imaging (MRI). The mandibular bone marrow with abnormal signals (T1-weighted imaging: low, T2-weighted imaging: low or high, short-tau inversion recovery: high) on MRI, and no qualitative characteristic CT and oral findings indicative of osteonecrosis (exposed bone, sequestrum, periosteal reaction, and osteolysis) was identified as 0 MRONJ. Texture features of the bone marrow of the mandible with MRONJ and the contralateral, normal mandibular bone marrow were extracted using an open-access software, namely, LIFEx. The volumes of interest (VOIs) were manually placed on CT images by tracing the bilateral mandibular bone marrow regions, excluding the teeth, mandibular canal, and cortical bone. Thirty-seven texture features were extracted from each VOI. RESULTS: Six gray-level run length matrix features and four gray-level zone length matrix features exhibited significant differences between mandibular bone marrow with and without MRONJ. CONCLUSIONS: CT was able to quantitatively assess texture features of normal mandibular bone marrow and that with MRONJ. Texture analysis may be useful as a new method for detecting stage 0 MRONJ using CT.

ASSESSMENT OF LEUKOCYTES FUNCTION IN PERIPHERAL BLOOD IN PATIENTS WITH MEDICINAL JAWS OSTEONEKROSIS.

The aim of the study was to assess the functional activity of peripheral blood phagocytes in patients with drug-induced osteonecrosis of the jaws to develop a new approach to treatment. A total of 35 people were examined, including: 10 healthy individuals, 8 with purulent-inflammatory diseases of the maxillofacial region (GVZ ChLO), 17 patients with medical osteonecrosis of the jaws (MRONJ). Among patients with MRONJ, there were 10 men and 7 women, aged from 54 to 73 years, with a mean age of 62 years. She had a history of cancer (prostate cancer, breast cancer). In connection with the presence of metastases, the patients took bisphosphonates - the drug Zometa (zoledronic acid) in injections of 4 mg intravenously 1 time per month. Phagocytic activity of peripheral blood leukocytes was determined by flow cytometry. The examination of the patients was carried out before and on the 14th day after the surgical treatment, osteonecrectomy. In patients with MRONJ and HVD, the phagocytic activity of leukocytes was reduced by 30-40% compared with healthy individuals (p<0.05). Low phagocytic activity was confirmed by the indicators of stimulation of E. coli leukocytes and the stimulation index (oxidative burst). On the 14th day after surgical treatment in patients with BRONJ, the leukocyte phagocytosis indices did not normalize. The dysfunction of macrophage cells is more pronounced in cancer patients treated with bisphosphonates than in patients with HVD ChLH. A low level of indices of innate immunity factors contributes to the recurrence of osteonecrosis.

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.

A New Medical Record Proposal to the Prognostic Risk Assessment for MRONJ in Oncologic Patients: "Sapienza Head and Neck Unit" Proposal.

Medication-related osteonecrosis of the jaw (MRONJ) is an adverse event associated with antiresorptive and antiangiogenic drugs. The use of these drugs in the treatment of cancer patients with bone metastasis is necessary and standardized in the literature. A multidisciplinary approach for the patient's management is strongly recommended. Therefore, it should be necessary to integrate the path of these subjects with a dedicated dental screening in order to first assess the individual risk of developing a MRONJ, and then to plan dental treatments and oral hygiene sessions, and finally to schedule a follow-up to intercept and treat early osteonecrosis. The aim of this manuscript is to propose a new simple medical report to evaluate patients affected by metastatic bone cancer in order to reduce the risk of developing MRONJ.

Microvascular Reconstruction of Osteonecrosis: Assessment of Long-term Quality of Life.

OBJECTIVE: Review long-term clinical and quality-of-life outcomes following free flap reconstruction for osteonecrosis. STUDY DESIGN: Retrospective multi-institutional review. SETTING: Tertiary care centers. METHODS: Patients included those undergoing free flap reconstructions for osteonecrosis of the head and neck (N = 232). Data included demographics, defect, donor site, radiation history, perioperative management, diet status, recurrence rates, and long-term quality-of-life outcomes. Quality-of-life outcomes were measured using the University of Washington Quality of Life (UW-QOL) survey. RESULTS: Overall flap success rate was 91% (n = 212). Relative to preoperative diet, 15% reported improved diet function at 3 months following reconstruction and 26% at 5 years. Osteonecrosis recurred in 14% of patients (32/232); median time to onset was 11 months. Cancer recurrence occurred in 13% of patients (29/232); median time to onset was 34 months. Results from the UW-QOL questionnaire were as follows: no pain (45%), minor or no change in appearance (69%), return to baseline endurance level (37%), no limitations in recreation (40%), no changes in swallowing following reconstruction (28%), minor or no limitations in mastication (29%), minor or no speech difficulties (93%), no changes in shoulder function (84%), normal taste function (19%), normal saliva production (27%), generally excellent mood (44%), and no or minimal anxiety about cancer (94%). CONCLUSION: The majority of patients maintained or had advancement in diet following reconstruction, with low rates of osteonecrosis or cancer recurrence and above-average scores on UW-QOL survey suggesting good return of function and quality of life.

Risk assessment of bisphosphonate-related osteonecrosis of the jaw based on CBCT scans / A biszfoszfonátkezelés állcsontnekrózist eloidézo kockázatának megítélése CBCT-felvételek alapján.

INTRODUCTION: Bisphosphonate-related osteonecrosis of the jaw is a condition that severely affects the quality of life, therefore an early diagnosis is of utmost importance (both from a general and a surgical point of view), alongside with an accurate assessment of the risk of emergence of the disease. AIM: Estimation of the prognosis is not resolved; among several radiological options those used in dentistry seem the most fit for the purpose, with cone-beam computed tomography (CBCT) being superior in this task. Assessment of the risk of BRONJ developed following orally applied bisphosphonate is unemphatic in most case studies - these focus more on the intravenous application carrying a greater risk of BRONJ. METHOD: In contrast with the studies published so far, we performed our measurements on preoperative CBCT scans, thereby directly studying the possibility of risk assessment. Our measurements were conducted through evaluating CBCT scans. We chose the frontal section in the midline of the mental foramen as the representative area. We measured density and thickness of the cortical bone on several given points; the diameter of the mental foramen was also measured. In the first group, we examined patients suffering from osteoporosis who had developed BRONJ following oral bisphosphonate treatment. In the second group, we looked at patients suffering from osteoporosis, who had received oral bisphosphonate therapy for this condition but did not develop BRONJ after oral surgery. As control group, we chose patients suffering from osteoporosis who had not received any of the medications known to cause BRONJ. RESULTS: Based on our results, it is clear that there is no significant difference in the bone density of those patients who developed BRONJ and those who did not, examining the preoperative CBCT scans. CONCLUSIONS: Using CBCT scans (and thereby submitting the patient to radiation exposure) in order to estimate the possibility of BRONJ following oral bisphosphonate treatment for osteoporosis is not recommended. It is important not to expose patients to more radiation than strictly necessary to predict BRONJ following oral bisphosphonate treatment in accordance with the ALARA (as low as reasonably achievable) principle. Orv Hetil. 2020; 161(21): 867-872.

General and Specific Considerations as to why Osteoporosis-Related Care Is Often Suboptimal.

PURPOSE OF REVIEW: The assessment of fracture risk and use of antiosteoporosis medications have increased greatly over the last 20-30 years. However, despite this, osteoporosis care remains suboptimal worldwide. Even in patients who have sustained a fragility fracture, fewer than 20% actually receive appropriate antiosteoporosis therapy in the year following the fracture. There is also evidence that treatment rates have declined substantially in the last 5-10 years, in many countries. The goal of this article is to consider the causes for this decline and consider how this situation could be remedied. RECENT FINDINGS: A number of possible reasons, including the lack of prioritisation of osteoporosis therapy in ageing populations with multimorbidity, disproportionate concerns regarding the rare side effects of anti-resorptives and adverse changes in reimbursement in the USA, have been identified as contributing factors in poor osteoporosis care. Improved secondary prevention strategies; screening measures (primary prevention) and appropriate, cost-effective guideline and treatment threshold development could support the optimisation of osteoporosis care and prevention of future fractures.

Duration of Bisphosphonate Drug Holidays and Associated Fracture Risk.

BACKGROUND: Discontinuation of bisphosphonates (BP) or a "drug holiday" after several years of treatment is increasingly common. However, the association of drug holiday duration with future fracture risk is unclear. OBJECTIVES: We evaluated the rate of fracture in relation to various lengths of drug holidays among women receiving long-term BP therapy. RESEARCH DESIGN: Observational cohort study using US Medicare data 2006-2016. Incidence rates (IRs) and Cox proportional hazards models were used to evaluate the rate and adjusted hazard ratios (aHRs) controlling for potential confounders. SUBJECTS: Women aged 65 years and above enrolled in fee-for-service Medicare who had been adherent (≥80%) to alendronate, risedronate, or zoledronate for ≥3 years. MEASURES: Hip, humerus, distal forearm, and clinical vertebral fracture. RESULTS: Among 81,427 eligible women observed for a median (interquartile range) of 4.0 (2.5, 5.3) years, 28% of women underwent a drug holiday. In the alendronate cohort (73% overall), the IR of hip fracture among women who discontinued BP for >2 years was 13.2 per 1000 person-years. Risk was increased (aHR=1.3, 1.1-1.4) versus continuing therapy (IR=8.8, referent). Rates were elevated for humerus fracture with discontinuation >2 years (aHR=1.3, 1.1-1.66) and for clinical vertebral fracture with discontinuation >2 years (aHR=1.2, 1.1-1.4). Results were similar for risedronate, zoledronate, and ibandronate for hip and clinical vertebral fracture. CONCLUSION: Discontinuing alendronate beyond 2 years was associated with increased risk of hip, humerus, and clinical vertebral fractures.

Nitrogen-containing bisphosphonate therapy-Part II: Assessment of alveolar bone tissue inflammatory response in rats-A blind randomized controlled trial.

This study aimed to evaluate the alveolar bone tissue inflammatory response in rats undergoing zoledronic acid therapy. The study sample was composed of 28 Wistar rats. Animals from the test group GTa received a weekly intraperitoneal dose of 0.2 mg/kg of zoledronic acid for 3 weeks, while test group GTb received the same dose for 8 weeks. A physiological saline dose, equivalent to that of the medication, was administered to the controls in groups GCa and GCb. A defect was created in the dental crown of the lower first molars using a drill to simulate pulp and periapical injury. Data were evaluated regarding image grey levels by cone-beam computed tomography and histologically by assigning scores for the presence of inflammatory infiltrate, type of infiltrate, vascularization, bone necrosis and dental resorption. Grey levels in the 3-week therapy group (GTa) showed more pronounced changes in comparison with those seen in the GCa group (P < 0.05). Evaluation of the scores demonstrated no association between any of the variables amongst the groups (>0.05). However, bone remodelling decreased in the groups receiving the medication. Bone necrosis was present more frequently in group GTb than in the control group GCb. The results suggest that the drug interfered in the reaction capacity of the alveolar bone tissue as test group GTa showed higher grey levels in comparison to the control group GCa. In addition, there was less bone remodelling activity, with the appearance of bone necrosis zones and intense acute inflammatory infiltrate associated with the 8-week therapy group GTb.