Chemical and Radiation-Associated Jaw Lesions

Radiomorphometric indices for measuring mandibular bone quality in oncologic patients

OBJECTIVE

This retrospective study compared the thickness and degree of resorption of the mandibular cortex in patients with head and neck cancer (AG), patients with cancer at sites other than the head and neck (BG), and patients with no cancer (CG) to describe and compare the changes in the mandible after antineoplastic therapy and their possible clinical implications.

MATERIALS AND METHODS

A total of 287 panoramic radiographs were examined. The following radiomorphometric indices were analyzed: mental index (MI), panoramic mandibular index (PMI), and mandibular cortical index (MCI). Analysis of variance (ANOVA) and the Kruskal‒Wallis test, with p < 0.05 considered significant, were performed.

RESULTS

Males predominated in the AG (83%), while females predominated in the BG and CG (78.6 and 62%, respectively). In the AG, tongue carcinoma (22.1%) was prevalent, while in the BG, breast carcinoma was predominant (53.8%). All parameters measured in the AG and BG patients were significantly lower than those in the CG patients: MI (p < 0.001), right PMIc/a (p < 0.001), left PMIc/a (p < 0.001), right PMIc/b (p = 0.004), left PMIc/b (p < 0.001), and MCI (p < 0.001).

CONCLUSIONS

Radiomorphometric indices MI, PMI, and MCI were significantly lower in panoramic radiographs of patients with head and neck cancer and patients with cancer in other regions of the body than in those of nononcological patients.

Clinicopathologic features and exploration of new molecular mechanisms of radiation-induced bone injury: report of two cases and review of the literature

Radiation-induced bone injury (RBI) has a multifaceted mechanism of occurrence, is influenced by various factors, and is difficult to prevent. Clinicopathologic features and manifestations of disease progression were observed in two patients with distinct fractures: one with a left-sided fourth rib fracture after postoperative radiotherapy for lung cancer, and the other with a right-sided intertrochanteric femur fracture following accidental exposure to a 192Ir radiation source 5 years prior. These two clinical case reports discussed the clinicopathologic features of RBI and disease progression and utilized transcriptome sequencing to explore potential new targets for treating this type of RBI. Both patients exhibited similar incurable osteolytic bone destruction and fatty infiltration in their pathology. It is proposed that XIST, the most significantly upregulated gene identified by transcriptome sequencing analysis, maybe a potential target for understanding these molecular mechanisms.

Diagnostic and Therapeutic Approaches to Jaw Osteoradionecrosis

Jaw osteoradionecrosis (ORN) is a major complication of head and neck cancer radiotherapy. Treatment complications account for most of the poor outcomes for head and neck cancers and the associated racial health disparities in cancer survivorship. The global incidence of jaw ORN is improving due to pre-radiotherapy patient preparations and improved head and neck cancer radiotherapy protocols. The diagnosis and management of jaw ORN are based on the patient's history and clinical presentation combined with radiological and histopathological tests. Evidence-based jaw ORN therapies focus on preventive, palliative, and surgical principles. However, new and innovative therapeutic approaches based on the cellular and molecular pathophysiological processes of jaw ORN and the jawbone's susceptibility to radiation bone damage are limited. The rationale for this narrative review is to highlight the current diagnostic approaches to jaw ORN and the pathophysiological basis for new therapeutic options for ORN.

Craniofacial disorders and dysplasias: Molecular, clinical, and management perspectives

There is a wide spectrum of craniofacial bone disorders and dysplasias because embryological development of the craniofacial region is complex. Classification of craniofacial bone disorders and dysplasias is also complex because they exhibit complex clinical, pathological, and molecular heterogeneity. Most craniofacial disorders and dysplasias are rare but they present an array of phenotypes that functionally impact the orofacial complex. Management of craniofacial disorders is a multidisciplinary approach that involves the collaborative efforts of multiple professionals. This review provides an overview of the complexity of craniofacial disorders and dysplasias from molecular, clinical, and management perspectives.

Application of Panoramic Radiography in the Detection of Osteopenia and Osteoporosis-Current State of the Art

PURPOSE OF REVIEW

Osteoporosis ranks high among morbidities in the elderly as it is a natural process to lose bone, making them susceptible to fractures from minor falls. The cost of managing these patients is staggering. The fractures can be prevented with better care of the elderly, and by treating the major predisposing factor, osteoporosis. Clinicians and scientists, in general, constantly look for early diagnostic and prognostic indicators for osteopenia and osteoporosis to proactively prevent fractures. Dental panoramic radiography (DPR) is a rotational pantomography used for identifying dental pathology in patients. Early signs of osteopenia and osteoporosis can be identified in DPR. The usefulness of notable jaw changes in DPR to predict osteopenia and osteoporosis is still evolving as more studies continue to delve into this concept. The purpose of this review is to present advances made in the practical application of DPR for predicting early onset of osteopenia and osteoporosis.

RECENT FINDINGS

Dental panoramic radiography, a form of tomography commonly used by dental practitioners, has been the standard of care for decades for detecting dento-alveolar pathology. Several technological advancements have taken place with respect to the use of DPR. These include conversion from plain film to digital radiography, advancements in the manufacture of flat panel detectors, and accurate imaging of the layers of mandible and maxilla that has become possible with appropriate patient positioning within the focal trough of the machine. Improvements in the software infrastructure make it easier to view, enhance, and save the radiographic images. The radiographic appearance of the trabecular bone within the mandible and indices measured from the dental panoramic radiographs focusing on the inferior cortex of the mandible are considered useful tools for identifying asymptomatic individuals with osteoporosis or at risk for developing osteoporosis. These indices apparently correlate with risks of fragility fractures of osteoporosis in other parts of the body. Dental panoramic radiography (DPR) is a commonly used radiographic procedure in dentistry for evaluation of teeth and associated maxillofacial structures. The evaluation of the inferior border of the mandible for reduction or loss of cortical thickness and evaluation of the trabecular bone within the mandible are helpful markers for early signs of osteopenia to identify patients at risk for osteoporosis. This review focused on research advancements on practical application of DPR in early identification of osteopenia and osteoporosis.

Oral Implications of Polypharmacy in Older Adults

Over the next several decades, rates of aged populations will increase rapidly. These populations are susceptible to multimorbidities and polypharmacy (concurrently, prescribed 5 or more medications). Many medications have side effects that manifest orally. Therefore, it essential to possess current pharmacologic knowledge to diagnose and treat oral implications of commonly prescribed medications. This article details common medication-induced oral lesions and patient assessment of risk factors for polypharmacy and provides a template to integrate medication reconciliation into dental clinical practice.

Conditioned Medium from Bone Marrow Mesenchymal Stem Cells Restored Oxidative Stress-Related Impaired Osteogenic Differentiation

Oxidative stress from high levels of intracellular reactive oxygen species (ROS) has been linked to various bone diseases. Previous studies indicate that mesenchymal stem cells (MSC) secrete bioactive factors (conditioned medium (MSC-CM)) that have antioxidant effects. However, the antioxidant role of MSC-CM on osteogenesis has not been fully studied. We aimed to identify antioxidant proteins in MSC-CM using mass spectrometry-based proteomics and to explore their effects on osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSC) exposed to oxidative stress induced by hydrogen peroxide (H₂O₂). Our analysis revealed that MSC-CM is comprised of antioxidant proteins that are involved in several biological processes, including negative regulation of apoptosis and positive regulation of cell proliferation. Then, hBMSC exposed to H₂O₂ were treated with MSC-CM, and the effects on their osteogenic differentiation were evaluated. MSC-CM restored H₂O₂-induced damage to hBMSC by increasing the antioxidant enzyme-SOD production and the mRNA expression level of the anti-apoptotic BCL-2. A decrease in ROS production and cellular apoptosis was also shown. MSC-CM also modulated mRNA expression levels of osteogenesis-related genes, runt-related transcription factor 2, collagen type I, bone morphogenic protein 2, and osteopontin. Furthermore, collagen type I protein secretion, alkaline phosphatase activity, and in vitro mineralization were increased. These results indicate that MSC-CM contains several proteins with antioxidant and anti-apoptotic properties that restored the impaired hBMSC osteogenic differentiation associated with oxidative stress.

Primary Cilia Enhance Osteogenic Response of Jaw Mesenchymal Stem Cells to Hypoxia and Bisphosphonate

PURPOSE

Primary cilia play a significant role in mesenchymal stem cell (MSC) lineage commitment, skeletal development, and bone homeostasis. MSC responsiveness to metabolic stress is associated with radiation and drug-induced jaw osteonecrosis. Therefore, we hypothesize that orofacial MSCs (OFMSCs) osteogenic commitment in response to cellular stressors hypoxia and bisphosphonates is a survival response coupled to primary cilia biogenesis.

MATERIALS AND METHODS

Human OFMSCs were subjected to cellular stress using severe hypoxia, nitrogen-containing bisphosphonate (pamidronate) and low serum starvation. OFMSC primary cilia formation, as well as cell survival and proliferation, were detected using immunofluorescence, CellTitre-Glo, and WST-1 assays respectively. OFMSC differentiation was tested using Alizarin Red S staining. OFMSCs survival and osteogenic markers were assessed by western blotting relative to primary cilia number and associated acetylated tubulin levels.

RESULTS

Baseline OFMSC proliferation was stable under short-term severe hypoxia and pamidronate treatments whether combined with or without serum starvation. Hypoxia and pamidronate decreased the number of OFMSCs positive for primary cilia that was consistent with increased HIF-1α and caspase 3 but decreased cyclin D1. Combined effects of hypoxia and pamidronate on OFMSCs significantly reduced ciliation but did not completely abrogate it. Combination of serum deprivation, hypoxia, and pamidronate promoted OFMSCs osteogenic differentiation that was consistent with upregulated HIF-1α levels.

CONCLUSIONS

Partial rather than complete loss of OFMSC ciliation and enhanced osteogenic commitment represent adaptive survival response of OFMSCs to severe hypoxia and pamidronate-induced metabolic stress. Hypoxia and drug-induced OFMSC stress may be significant events governing the pathogenesis and clinical outcomes of jaw osteonecrosis.

Practical Approach to Radiopaque Jaw Lesions

Radiopaque lesions of the jaw are myriad in type and occasionally protean in appearance. In turn, the radiologic analysis of these lesions requires a systematic approach and a broad consideration of clinical and imaging characteristics to enable reliable radiologic diagnosis. Initially categorizing lesions by attenuation pattern provides a practical framework for organizing radiopaque jaw lesions that also reflects important tissue characteristics. Specifically, the appearance of radiopaque lesions can be described as (a) densely sclerotic, (b) ground glass, or (c) mixed lytic-sclerotic, with each category representing a distinct although occasionally overlapping differential diagnosis. After characterizing attenuation pattern, the appreciation of other radiologic features, such as margin characteristics or relationship to teeth, as well as clinical features including demographics and symptoms, can aid in further narrowing the differential diagnosis and lend confidence to clinical decision making. The authors review the potential causes of a radiopaque jaw lesion, including pertinent clinical and radiologic features, and outline a simplified approach to its radiologic diagnosis, with a focus on cross-sectional CT. An invited commentary by Buch is available online. ^©RSNA, 2021.

Radiographic Diagnosis of Systemic Diseases Manifested in Jaws

Radiographic changes of the oral and maxillofacial hard tissues can be an indication of an underlying systemic disease. In this article, the range of individual disease entities that have both systemic and dental manifestations are reviewed. Images for many conditions are provided to illustrate the radiographic changes. A summary of the most common jaw affected, radiographic and pathognomonic findings, and management aspects is listed in a table format within this article for quick reference.

Mandibular osteonecrosis following herpes zoster infection: Report of a rare case with a literature review

Any patient with a herpes zoster infection of the mandibular branch of the trigeminal nerve should benefit from early oral monitoring, especially in elderly population where traumatic dental prostheses are common, because osteonecrosis can occur.

Schemes for Drug-Induced Treatment of Osteonecrosis of Jaws with Particular Emphasis on the Influence of Vitamin D on Therapeutic Effects

Drugs that inhibit bone resorption are prescribed most often by orthopedists, hematologists, or oncologists. Dental practice rarely draws attention to their importance and the effects they carry. The problem concerns mainly older people owing to oncological problems or postmenopausal consequences, but everyone can be at risk. Carefully conducted interviews and analysis of history and disease should always be performed before any action is taken by patients taking this type of medicine. Further action should consider possible complications and, above all, the risk of their occurrence. In this article, the most important issues related to the treatment of drug-induced osteonecrosis of the jaws (ONJ) are raised, including medication-related osteonecrosis of the jaw (MRONJ); conservative treatment, including the use of laser; and the impact of vitamin D supplementation on the overall treatment, prognosis, and prevention before complication, which is osteonecrosis of the jaw in the course of treatment with bisphosphonates and other drugs predisposing to MRONJ, such as denosumab and angiogenesis inhibitors. The degree of osteonecrosis is also critical, as it is possible to avoid surgical procedures for only conservative methods that sometimes bring good results. Surgical treatment of advanced stages is complicated and carries a high risk of error and complications. MRONJ is a disease that is easy to avoid, but it is difficult to treat and treatment sometimes leads only to a partial remission of the disease, not a complete cure.

Oral Implications of Polypharmacy in Older Adults

Over the next several decades, rates of aged populations will increase rapidly. These populations are susceptible to multimorbidities and polypharmacy (concurrently, prescribed 5 or more medications). Many medications have side effects that manifest orally. Therefore, it essential to possess current pharmacologic knowledge to diagnose and treat oral implications of commonly prescribed medications. This article details common medication-induced oral lesions and patient assessment of risk factors for polypharmacy and provides a template to integrate medication reconciliation into dental clinical practice.

The Outcome of Primary Root Canal Treatment in Postirradiated Patients: A Case Series

Osteoradionecrosis (ORN) of the jaw is considered the most severe long-term adverse effect that can occur in radiation therapy patients. Teeth extractions and dental diseases are the main risk factors for ORN in irradiated patients. The aim of this case series was to evaluate the outcome of primary root canal treatments performed on patients who underwent head and neck radiotherapy and to evaluate any ORN related to the endodontic treatment. In this case series, primary root canal therapies (absence of radiolucency) were performed on 10 teeth of 8 patients who underwent radiotherapy for head and neck cancers. Radiation doses to the periapical area were calculated using the radiotherapy planning computed tomographic scan. After a 277-day mean follow-up, all patients were asymptomatic, no teeth showed periapical radiolucency, and no ORN was observed. Even if a limitation of buccal opening occurred after radiotherapy and complicated the endodontic procedures, root canal therapy seemed to be safe and a valid alternative to tooth extraction.

Development of an experimental model for radiation-induced inhibition of cranial bone regeneration

Background

Radiation therapy is widely employed in the treatment of head and neck cancer. Adverse effects of therapeutic irradiation include delayed bone healing after dental extraction or impaired bone regeneration at the irradiated bony defect. Development of a reliable experimental model may be beneficial to study tissue regeneration in the irradiated field. The current study aimed to develop a relevant animal model of post-radiation cranial bone defect.

Methods

A lead shielding block was designed for selective external irradiation of the mouse calvaria. Critical-size calvarial defect was created 2 weeks after the irradiation. The defect was filled with a collagen scaffold, with or without incorporation of bone morphogenetic protein 2 (BMP-2) (1 μg/ml). The non-irradiated mice treated with or without BMP-2-included scaffold served as control. Four weeks after the surgery, the specimens were harvested and the degree of bone formation was evaluated by histological and radiographical examinations.

Results

BMP-2-treated scaffold yielded significant bone regeneration in the mice calvarial defects. However, a single fraction of external irradiation was observed to eliminate the bone regeneration capacity of the BMP-2-incorporated scaffold without influencing the survival of the animals.

Conclusion

The current study established an efficient model for post-radiation cranial bone regeneration and can be applied for evaluating the robust bone formation system using various chemokines or agents in unfavorable, demanding radiation-related bone defect models.

Osteoradionecrosis prevalence and associated factors: A ten years retrospective study

BACKGROUND

Osteoradionecrosis (ORN) is one of the most serious complications of head and neck radiotherapy and is considered a public health problem worldwide. This study aims to determine the prevalence and associated factors of ORN in patients undergoing radiotherapy for head and neck malignancy.

MATERIAL AND METHODS

A cross-sectional retrospective study was conducted, in which all medical records of patients undergoing head and neck radiation in the period between 2006 to 2015 (10 years) were examined. Clinical and demographic data were extracted. Multivariate Poisson regression analysis with robust variance was employed to access the relationship between ORN and independent variables (p < 0.05; 95% CI).

RESULTS

The sample comprised 413 medical records of patients undergoing radiotherapy. The prevalence of ORN was 9.7 %. Most participants were males (78.2%). The mean age of subjects was 55 years (± 14 years). The mandible was the main site of occurrence of ORN (85.0%). The following variables were associated with ORN : presence of oral mucositis (PR = 3.03; 95% CI: 1.30-7.03), history of smoking (PR = 0.23; 95% CI: 0.07-0.74), number of teeth removed before radiotherapy (PR = 1.06; 95% CI: 1.01-1.11) and visit to the dentist before radiation (PR = 0.08; 95% CI: 1.02-1.11).

CONCLUSIONS

The prevalence of ORN was low and was associated with the presence of oral mucositis and the number of removed teeth before radiation. Visiting the dentist before radiotherapy and stop-ping smoking were protective factors for ORN.

Dental Management of Patients Who Have Undergone Oral Cancer Therapy

Oral cancer therapies are associated with orofacial complications that could result in dose-limiting cancer treatment and consequent suboptimal tumor control. Oral cancer treatment complications include oral mucositis, salivary gland hypofunction, odontogenic infections, pain, dermatitis, neurotoxicity, soft tissue fibrosis, trismus, osteoradionecrosis, and potential cancer recurrence. These complications significantly affect cancer survivorship, quality of life, and psychosocial status. Effective dental management of patients with oral cancer involves the coordination of care among several health care professionals before, during, and after cancer therapy. The goal is to minimize complications, and establish optimal quality of life for survivors.

Ameloblastoma: current etiopathological concepts and management

Ameloblastoma is a benign odontogenic tumor of epithelial origin. It is locally aggressive with unlimited growth capacity and has a high potential for malignant transformation as well as metastasis. Ameloblastoma has no established preventive measures although majority of patients are between ages 30 and 60 years. Molecular and genetic factors that promote oncogenic transformation of odontogenic epithelium to ameloblastoma are strongly linked to dysregulation of multiple genes associated with mitogen-activated protein kinase, sonic hedgehog, and WNT/β-catenin signaling pathways. Treatment of ameloblastoma is focused on surgical resection with a wide margin of normal tissue because of its high propensity for locoregional invasion; but this is often associated with significant patient morbidity. The relatively high recurrence rate of ameloblastoma is influenced by the type of molecular etiological factors, the management approach, and how early the patient presents for treatment. It is expected that further elucidation of molecular factors that orchestrate pathogenesis and recurrence of ameloblastoma will lead to new diagnostic markers and targeted drug therapies for ameloblastoma.

Impact of communication between physicians and dentists on the incidence of jaw osteonecrosis caused by bone anti-resorptives

Dental management of osteoporosis patients on anti-resorptive therapy can be challenging for both the dentist and physician because of the risk of osteonecrosis of the jaw (ONJ). This editorial reflects on the paper written by Tagushi et al that expressed a relative lack of communication between health care providers when treating osteoporosis patients. Osteoporosis-related bone fractures can be debilitating and occasionally lethal, but management with anti-resorptives is vital while cognizant of the complication of ONJ that can also negatively impact patient’s quality of life.

Hyperbaric oxygen therapy and osteonecrosis

Osteonecrosis of the jaw may be caused by radiation, medication, or infection. Optimal therapy requires a multimodal approach that combines surgery with adjuvant treatments. This review focuses on the use of adjunctive hyperbaric oxygen therapy for this condition. In addition to evidence regarding the basic and clinical science behind hyperbaric oxygen therapy, controversies in the field and economic implications are discussed.