Osteoradionecrosis of the jaws--a current overview--Part 2: dental management and therapeutic options for treatment

Pre- and Post-Operative Quality of Life in Patients with Osteoradionecrosis of the Jaw

Osteoradionecrosis of the jaw (ORNJ) is a feared complication following radiation therapy performed for oncological treatment of head and neck cancers (HNC). To date, there is no clear evidence regarding the impact of surgical treatment of ORNJ on the quality of life (QoL) of affected patients. However, understanding the significance of the surgical treatment approach and its effects on QoL is an essential factor in the decision-making process for optimal, individualized therapy. In this prospective clinical study, QoL was assessed in relation to health related QoL (HRQoL) and oral health related QoL (OHQoL) before and after surgical treatment of ORNJ using standardized questionnaires (EORTC QLQ-C30, QLQ-HN35, OHIP-14). The overall QoL scores as well as individual domains of the collected scales regarding functional and symptom-related complaints were statistically analyzed. Subgroups concerning age, gender, different risk factors and type of ORNJ therapy were compared using Kruskal Wallis test. In addition, clinical and demographic patient data were collected and analyzed. QoL improvement correlated with the type of surgical ORNJ and the length of hospitalization. Better QoL scores were achieved post-operatively regarding different symptoms like pain, swallowing and mouth opening. Long-term effects of radiation therapy remained visibly restrictive to QoL and worsen over time.

Mandibular Osteoradionecrosis: Defining the Microbial Milieu and Antimicrobial Resistance at the Time of Rescue Flap Surgery

OBJECTIVE

To report the microorganisms and their antibiotic sensitivity profile from tissue cultures and stains at the time of anterolateral thigh fascia lata (ALTFL) rescue flap for management of mandibular osteoradionecrosis (ORN).

METHODS

Retrospective chart review of patients who underwent ALTFL rescue flap for native mandibular ORN between 2011 and 2022.

RESULTS

Twenty-six cases comprising 24 patients (mean age 65.4 years, 65.4% male) with mandibular ORN from whom tissue cultures and gram stain were obtained at the time of ALTFL rescue flap. 57.7% grew bacterial species, while 34.6% grew fungal species. Multibacterial speciation was noted in 26.9% of cultures. A combination of bacterial and fungal growth was also seen in 15.4% of cases. All gram-positive cocci (GPC) were pansensitive to antibiotics except for one case of Staphylococcus aureus, which was resistant to levofloxacin. Gram-negative bacilli (GNB) species were isolated in 50.0% of cases. All fungal growth was due to Candida species. No growth was noted in 23.1% of cases. Multidrug resistance was noted in 53.8% of cases when GNB was isolated.

CONCLUSION

We report 76.9% of our cases of mandibular ORN had microbial growth from tissue cultures obtained at the time of the ALTFL rescue flap. Fungal growth was noted in a substantial number of cases and should be obtained as a specimen when pursuing culture-driven antibiotic therapy. Most GPCs were pansensitive to antibiotics, while GNBs were often the harbinger of multidrug resistant mandibular ORN.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:166-169, 2024.

Oral Surgery and Osteoradionecrosis in Patients Undergoing Head and Neck Radiation Therapy: An Update of the Current Literature

Osteoradionecrosis (ORN) is a serious long-term complication of head and neck radiotherapy (RT), which is often triggered by dental extractions. It results from avascular aseptic necrosis due to irradiated bone damage. ORN is challenging to treat and can lead to severe complications. Furthermore, ORN causes pain and distress, significantly reducing the patient's quality of life. There is currently no established preventive strategy. This narrative review aims to provide an update for the clinicians on the risk of ORN associated with oral surgery in head and neck RT patients, with a focus on the timing suitable for the oral surgery and possible ORN preventive treatments. An electronic search of articles was performed by consulting the PubMed database. Intervention and observational studies were included. A multidisciplinary approach to the patient is highly recommended to mitigate the risk of RT complications. A dental visit before commencing RT is highly advised to minimize the need for future dental extractions after irradiation, and thus the risk of ORN. Post-RT preventive strategies, in case of dento-alveolar surgery, have been proposed and include antibiotics, hyperbaric oxygen (HBO), and the combined use of pentoxifylline and tocopherol ("PENTO protocol"), but currently there is a lack of established standards of care. Some limitations in the use of HBO involve the low availability of HBO facilities, its high costs, and specific clinical contraindications; the PENTO protocol, on the other hand, although promising, lacks clinical trials to support its efficacy. Due to the enduring risk of ORN, removable prostheses are preferable to dental implants in these patients, as there is no consensus on the appropriate timing for their safe placement. Overall, established standards of care and high-quality evidence are lacking concerning both preventive strategies for ORN as well as the timing of the dental surgery. There is an urgent need to improve research for more efficacious clinical decision making.

Clinical outcomes of dental implants in head and neck cancer patients: An overview

OBJECTIVE

The aim of this study was to evaluate the clinical outcomes of dental implants (DIs) in patients with head and neck cancer (HNC) treated with radiotherapy (RT), isolated chemotherapy, or bone modifying agents (BMAs).

STUDY DESIGN

This study was registered in the Prospective Register of Systematic Reviews (CRD42018102772); conducted via the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist; and based on PubMed, Scopus, Embase, Cochrane Library, Web of Science, and gray literature searches. The selection of studies was performed in 2 phases by 2 independent reviewers. The risk of bias (RoB) was assessed by the Measurement Tool to Assess the Methodological Quality of Systematic Reviews 2.

RESULTS

Twenty systematic reviews were included in the qualitative analysis. The majority scored as having high RoB (n = 11). Primary DIs placement in the mandible of patients with HNC subjected to RT doses <50 Gy was associated with better survival rates.

CONCLUSIONS

The placements of DIs could be considered safe in patients with HNC in sites of alveolar bone that received RT (≤5000 Gy); however, no conclusions could be made in patients with cancer managed by chemotherapy or BMAs. Due to the heterogeneity of studies included, the recommendation for DIs placement in patients with cancer should be carefully considered. Future better controlled randomized clinical trials are required to provide enhanced clinical guidelines for best patient care.

Osteonecrosis of the Jaws: An Update and Review of Literature

Aim

To provide a concise review on risk factors, stages, pathophysiology, prevention and possible treatment options for both MRONJ and ORN individually.

Methods

The review was conducted according to the 'Preferred Reporting Items for Systematic Reviews and Meta-Analyses' (PRISMA) guidelines. A comprehensive search of the PUBMED, Ebsco, SCOPUS, WEB OF SCIENCE and NDH for articles published up until 2021 was performed. After screening and full text analyses, 44 studies were included in this review. Definition, risk factors, etiology, symptoms, stages, pathophysiology, prevention and possible management options were explored and highlighted in this article.

Results

Three studies described osteonecrosis of jaw (ONJ) in general, 15 studies described ONJ associated with radiotherapy and 26 studies described ONJ associated with medications. Both the two conditions (ORN) and (MRONJ) have relatively similar clinical presentations clearing the fact that a resemblance in clinical presentations does not necessarily denote a similar pathophysiology.

Conclusion

However, various advancements have been made in the control and management of ONJ, but until and unless need for high tumoricidal doses exists, ONJ will certainly continue to remain as a clinical challenge demanding satisfactory treatment to improve the quality of life of the patient.

The Progress in Reconstruction of Mandibular Defect Caused by Osteoradionecrosis

Osteoradionecrosis (ORN) is described as a disease with exposed, nonviable bone that fails to heal spontaneously or by means of conservative treatment after radiotherapy in at least 3 months. Though traditional theories in the early stage including hypoxic-hypocellular-hypovascular and fibro-atrophic in addition to new findings such as ferroptosis were put forward to explain the mechanisms of the osteoradionecrosis, the etiology of ORN is still unclear. With the high rate of occurrence in the head and neck area, especially in the mandible, this disease can disrupt the shape and function of the irradiated area, leading to a clinical presentation ranging from stable small areas of asymptomatic exposed bone to severe progressive necrosis. In severe cases, patients may experience pain, xerostomia, dysphagia, facial fistulas, and even a jaw defect. Consequently, sequence therapy and sometimes extensive surgery and reconstructions are needed to manage these sequelae. Treatment options may include pain medication, antibiotics, the removal of sequesters, hyperbaric oxygen therapy, segmental resection of the mandible, and free flap reconstruction. Microanastomosed free-flaps are considered to be promising choice for ORN reconstruction in recent researches, and new methods including three-dimensional (3-D) printing, pentoxifylline, and amifostine are used nowadays in trying increase the success rates and improve quality of the reconstruction. This review summarizes the main research progress in osteoradionecrosis and reconstruction treatment of osteoradionecrosis with mandibular defect.

Osteoradionecrosis of the Jaw Following Proton Radiation Therapy for Patients With Head and Neck Cancer

Importance

Proton radiation therapy (PRT) has reduced radiation-induced toxic effects, such as mucositis and xerostomia, over conventional photon radiation therapy, leading to significantly improved quality of life in patients with head and neck cancers. However, the prevalence of osteoradionecrosis (ORN) of the jaw following PRT in these patients is less clear.

Objective

To report the prevalence and clinical characteristics of ORN in patients with oral and oropharyngeal cancer (OOPC) treated with PRT.

Design, Setting, and Participants

This case series reports a single-institution experience (Memorial Sloan Kettering Cancer Center, New York, New York) between November 2013 and September 2019 and included 122 radiation therapy-naive patients with OOPC treated with PRT. Data were analyzed from 2013 to 2019.

Main Outcomes and Measures

Clinical parameters, including sex, age, comorbidities, tumor histology, concurrent chemotherapy, smoking, comorbidities, and preradiation dental evaluation, were obtained from the medical record. Patients with clinical or radiographic signs of ORN were identified and graded using the adopted modified Glanzmann and Grätz grading system. Characteristics of ORN, such as location, clinical presentation, initial stage at diagnosis, etiology, time to diagnosis, management, and clinical outcome at the last follow-up, were also collected.

Results

Of the 122 patients (mean [SD] age, 63 [13] years; 45 [36.9%] women and 77 [63.1%] men) included in this study, 13 (10.6%) developed ORN following PRT during a median (range) follow-up time of 40.6 (<1-101) months. All patients had spontaneous development of ORN. At the time of initial diagnosis, grade 0, grade 1, grade 2, and grade 3 ORN were seen in 2, 1, 9, and 1 patient, respectively. The posterior ipsilateral mandible within the radiation field that received the full planned PRT dose was the most involved ORN site. At a median (range) follow-up of 13.5 (0.2-58.0) months from the time of ORN diagnosis, complete resolution, stable condition, and progression of ORN were seen in 3, 6, and 4 patients, respectively. The 3-year rates of ORN and death in the total cohort were 5.2% and 21.5%, while the 5-year rates of ORN and death were 11.5% and 34.4%, respectively.

Conclusions and Relevance

In this case series, the prevalence of ORN following PRT was found to be 10.6%, indicating that ORN remains a clinical challenge even in the era of highly conformal PRT. Clinicians treating patients with OOPC with PRT should be mindful of this complication.

Dental Care in Head and Neck Cancer Patients Undergoing Radiotherapy

External beam radiotherapy is an integral part of the management of head and neck cancer. Radiotherapy for head and neck cancer lead to many treatment-related toxicities, including a wide range of dental morbidities. These complications depend on the various patient and treatment-related factors. Patients with poor oral hygiene, pre-existing periodontal disease, and the conventional mode of radiotherapy delivery are major factors leading to acute and severe late dental problems. Most of the complications are preventable with proper oral and dental care before, during and after radiotherapy. Pre radiotherapy dental evaluation to diagnose patients with potential risk and timely intervention can reduce long-term morbidities like carries, osteoradionecrosis, etc., thereby improving patients' quality of life. This article highlights the various aspects of dental care and management in head neck cancer patients before, during and after radiation therapy.

Photobiomodulation therapy in management of cancer therapy-induced side effects: WALT position paper 2022

Disclaimer

This article is based on recommendations from the 12th WALT Congress, Nice, October 3-6, 2018, and a follow-up review of the existing data and the clinical observations of an international multidisciplinary panel of clinicians and researchers with expertise in the area of supportive care in cancer and/or PBM clinical application and dosimetry. This article is informational in nature. As with all clinical materials, this paper should be used with a clear understanding that continued research and practice could result in new insights and recommendations. The review reflects the collective opinion and, as such, does not necessarily represent the opinion of any individual author. In no event shall the authors be liable for any decision made or action taken in reliance on the proposed protocols.

Objective

This position paper reviews the potential prophylactic and therapeutic effects of photobiomodulation (PBM) on side effects of cancer therapy, including chemotherapy (CT), radiation therapy (RT), and hematopoietic stem cell transplantation (HSCT).

Background

There is a considerable body of evidence supporting the efficacy of PBM for preventing oral mucositis (OM) in patients undergoing RT for head and neck cancer (HNC), CT, or HSCT. This could enhance patients’ quality of life, adherence to the prescribed cancer therapy, and treatment outcomes while reducing the cost of cancer care.

Methods

A literature review on PBM effectiveness and dosimetry considerations for managing certain complications of cancer therapy were conducted. A systematic review was conducted when numerous randomized controlled trials were available. Results were presented and discussed at an international consensus meeting at the World Association of photobiomoduLation Therapy (WALT) meeting in 2018 that included world expert oncologists, radiation oncologists, oral oncologists, and oral medicine professionals, physicists, engineers, and oncology researchers. The potential mechanism of action of PBM and evidence of PBM efficacy through reported outcomes for individual indications were assessed.

Results

There is a large body of evidence demonstrating the efficacy of PBM for preventing OM in certain cancer patient populations, as recently outlined by the Multinational Association for Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). Building on these, the WALT group outlines evidence and prescribed PBM treatment parameters for prophylactic and therapeutic use in supportive care for radiodermatitis, dysphagia, xerostomia, dysgeusia, trismus, mucosal and bone necrosis, lymphedema, hand-foot syndrome, alopecia, oral and dermatologic chronic graft-versus-host disease, voice/speech alterations, peripheral neuropathy, and late fibrosis amongst cancer survivors.

Conclusions

There is robust evidence for using PBM to prevent and treat a broad range of complications in cancer care. Specific clinical practice guidelines or evidence-based expert consensus recommendations are provided. These recommendations are aimed at improving the clinical utilization of PBM therapy in supportive cancer care and promoting research in this field. It is anticipated these guidelines will be revised periodically.

Osteoradionecrosis of the jaw: A mini review

Osteoradionecrosis (ORN) of the jaw is one of the most dreaded complications of head and neck radiation therapy. Despite the evolution of radiation treatment modalities, ORN continues to remain a therapeutic challenge and its etiopathogenesis still remains unclear. It is clinically characterized by exposed necrotic bone within the head and neck radiation field. Over the past years, several studies have reported on the definition, staging, incidence, etiology, and management of this oral complication. In this review, we summarize the literature on ORN and discuss our institutional experience and management strategies that aim to predict and mitigate risk for ORN.

Fluorescence-guided surgery for osteoradionecrosis of the jaw: a retrospective study

OBJECTIVE

Osteoradionecrosis of the jaw (ORNJ) is one of the most severe head and neck complications in patients treated with radiotherapy. The goal of treatment is to suppress ORNJ progression. Currently, surgical removal of necrotic bone is an effective management approach for advanced stages. In this study, we present our experience in managing ORNJ using fluorescence-guided surgery.

METHODS

Nineteen ORNJ lesions in 15 hospitalized patients were treated with fluorescence-guided surgery. We retrospectively reviewed patients' demographic data, comorbidities, local preceding event, location, ORNJ stage, and treatment outcomes with a median follow-up of 12 months.

RESULTS

Twelve lesions (63%) were treated surgically under tetracycline fluorescence, and seven lesions (37%) were surgically treated under auto-fluorescence. Overall, four lesions (21%) achieved complete mucosal healing, eight lesions (42%) showed partial mucosal healing with bone exposure and no signs or symptoms of inflammation, and seven lesions (37%) were progressive. The results showed that either healing or ORNJ stabilization was achieved in 63% of lesions (n = 12).

CONCLUSION

Fluorescence-guided surgery can be beneficial in curing or stabilizing ORNJ. However, randomized clinical trials are needed to confirm these findings.

Dental Evaluation Prior to Cancer Therapy

A comprehensive oral examination and dental care prior to the start of cancer therapy is the standard of care in many cancer centers. This is because good oral health will likely minimize the undesirable complications such as opportunistic infections during cancer therapy. As the considerations differ between anti-neoplastic regimens, this chapter discusses the indications and rationale when planning and executing a treatment plan for patients undergoing various cancer therapies.

Pre-medical dental evaluation and treatment of oral infection - a survey study among hospital-affiliated dentists in Sweden

OBJECTIVE

To examine how hospital-affiliated dentists assess risk and evaluate oral foci of infection in patients facing certain medical treatments, and whether the nature of upcoming medical treatment affects the choice of dental intervention.

MATERIALS AND METHODS

A survey comprising six clinical cases (50 teeth) was sent to hospital-affiliated dentists in Sweden. A treatment option for the affected tooth/teeth in each case was selected whether the patient was facing heart valve surgery, chemotherapy, radiation therapy, intravenous bisphosphonate treatment, solid organ transplantation or was diagnosed with endocarditis.

RESULTS

Consensus in choice of dental treatment was high in 62%, moderate in 32% and low in 6% of the assessments. High variability of choice of treatment was seen for eight teeth whereas the remaining 42 teeth often received the same therapy regardless of medical issue. Chemotherapy and radiotherapy were thought to entail the highest risk for oral infectious sequelae with a risk ranging from 1% to 100%.

CONCLUSION

Pre-medical dental evaluations and recommended treatments are often uniform with the exception of the management of asymptomatic root canal treated teeth with persisting apical radiolucency and heavily decayed molars. In many instances, dental diagnosis has a greater impact on choice of treatment than the underlying medical issue and associated implications thereof.

Bacterial Colonization of the Condyle in Patients with Advanced Mandibular Osteoradionecrosis: Analysis of Hemimandibulectomy Specimens

Advanced mandibular osteoradionecrosis (ORN) sometimes requires extended resection (e.g., hemimandibulectomy). Bacterial infection contributes to ORN pathogenesis. To control infection and determine the extent of debridement required, an understanding of bacterial spread within sites of mandibular ORN is important. The current study used a histopathological approach to assess bacterial colonization in the mandibular condyle and elucidate possible paths of bacterial spread towards the mandibular condyle. Four hemimandibulectomy specimens were selected. Areas of bone destruction were macroscopically assessed and confirmed using hematoxylin and eosin staining. Bacterial presence within mandibular condyle was confirmed with Gram staining. Bone exposure was observed in the molar area in all specimens. Macroscopic bone destruction was apparent especially near the medial side of the cortical wall. Gram staining revealed bacterial colonization of the mandibular condyle in three of the four specimens. In conclusion, bacteria tended to spread posteriorly and through the medial side of the mandibular cortical wall. In patients with advanced ORN, the potential for bacterial colonization of the mandibular condyle should be considered during treatment.

The Balance between Orthodontic Force and Radiation in the Jawbone: Microstructural, Histological, and Molecular Study in a Rat Model

Simple Summary

Patients with head and neck cancer are frequently treated by radiation, which results in a lifelong risk of damage (necrosis) to the jawbones. Some of the irradiated young patients at a later time in life may be interested in orthodontic treatment for esthetic or functional purposes. We undertook this study in order to investigate changes that occur in irradiated jawbones when mild orthodontic force is applied in a rat laboratory model. We found that one low dose of radiation had negatively affected the jawbones and that these changes were visible in X-ray images as well as in microscopic slides. The irradiated bones seemed to be denser in the X-rays and had fewer cells that usually regulate normal bone turnover, compared to non-irradiated bones. However, when orthodontic force was applied after radiation, the changes in the irradiated bones were largely, but not completely, reversed in both X-rays and microscopy to the point that bone properties were approaching those of non-irradiated, orthodontically treated, bones. The findings of this study indicate that orthodontic force may have a beneficial effect on the maintenance of jawbone vitality after radiation, but additional studies using different time-lags between radiation and orthodontic force and higher radiation doses are warranted to support these findings.

Abstract

Irradiation of facial bones is associated with a lifelong risk of osteonecrosis. In a rat model, maxillae were exposed to a single 5 Gy dose of external beam radiation and orthodontic force was applied for 2 weeks on the first maxillary molar; control rats were treated identically without radiation. Tooth movement in irradiated jaws was 30% less than in controls, representing radiation-related damage. Micro-CT, histological, and molecular outcomes of orthodontic tooth movement were studied. Microstructurally, bone parameters (trabecular thickness, bone volume fraction, bone mineral density) were significantly affected by orthodontic force but not by radiation. Histological parameters were influenced only by orthodontic force, especially by an increase in osteoclasts. A molecular study revealed a differential distribution of cells expressing pre-osteoclast markers (RANK+—majority, CD11b+, CD14+—minority), with changes being influenced by orthodontic force (increased CD11b+ and CD14+ cells) and also by radiation (decreased RANK+ cells). The activation status of osteoclasts (TRAP staining) showed an orthodontic-force-related increase, which probably could not fully compensate for the radiation-associated impairment. The overall balance showed that orthodontic force had elicited a substantial microstructural, histological, and functional normalization process in irradiated maxillae but a radiation-induced impact was still conspicuous. Additional studies are needed to validate these findings.

Predictors of osteoradionecrosis following irradiated tooth extraction

Background

Tooth extraction post radiotherapy is one of the most important risk factors of osteoradionecrosis of the jawbones. The objective of this study was to determine the predictors of osteoradionecrosis (ORN) which were associated with a dental extraction post radiotherapy.

Methods

A retrospective analysis of medical records and dental panoramic tomogram (DPT) of patients with a history of head and neck radiotherapy who underwent dental extraction between August 2005 to October 2019 was conducted.

Results

Seventy-three patients fulfilled the inclusion criteria. 16 (21.9%) had ORN post dental extraction and 389 teeth were extracted. 33 sockets (8.5%) developed ORN. Univariate analyses showed significant associations with ORN for the following factors: tooth type, tooth pathology, surgical procedure, primary closure, target volume, total dose, timing of extraction post radiotherapy, bony changes at extraction site and visibility of lower and upper cortical line of mandibular canal. Using multivariate analysis, the odds of developing an ORN from a surgical procedure was 6.50 (CI 1.37–30.91, p = 0.02). Dental extraction of more than 5 years after radiotherapy and invisible upper cortical line of mandibular canal on the DPT have the odds of 0.06 (CI 0.01–0.25, p < 0.001) and 9.47 (CI 1.61–55.88, p = 0.01), respectively.

Conclusion

Extraction more than 5 years after radiotherapy, surgical removal procedure and invisible upper cortical line of mandibular canal on the DPT were the predictors of ORN.

[State of art of photobiomodulation in the management of radiotherapy adverse events: Indications and level of evidence]

PURPOSE

To evaluate the current and potential indications of photobiomodulation (PBM) and their level of evidence in the prevention or management of radiation therapy-related side effects.

MATERIALS AND METHODS

The Embase, Medline/PubMed, Cochrane, EBSCO, Scopus, and LILACS databases were systematically reviewed to include and analyze publications of clinical studies that have assessed PBM in the prevention or management of radiotherapy-related side effects. The keywords used were "photobiomodulation"; "low level laser therapy"; "acute oral mucositis"; "acute dysphagia"; "acute radiation dermatitis"; "lymphedema"; "xerostomia"; "hyposalivation"; "trismus"; "bone necrosis"; "osteoradionecrosis"; and "radiation induced fibrosis". Prospective studies were included, whereas retrospective cohorts and non-original articles were excluded from the analysis.

RESULTS

PBM in the red or infrared spectrum has demonstrated efficacy in randomized controlled trials in the prevention and management of radiotherapy-related side effects, especially acute oral mucositis, acute radiation dermatitis, and upper extremity lymphedema. The level of evidence associated with PBM was heterogeneous, but overall was still moderate. The main shortcomings were the diversity and lack of detail in treatment protocols, which could have compromised efficiency and reproducibility of PBM results.

CONCLUSION

The published data suggest that PBM may be considered as a full-fledged supportive care for patients treated with radiotherapy, or at least in the setting of a therapeutic clinical trial. However, until strong evidence has been published on its long-term safety, the use of PBM should be considered with caution, specifically when applied near areas with proven or potential tumors. The patient should be informed of the theoretical benefits and risks of PBM in order to obtain his informed consent before treatment.

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.

18F-FDG PET/CT in Osteoradionecrosis of the Hyoid

Osteoradionecrosis (ORN) is a well-documented complication following radiation treatment for head and neck malignancy. Facial bones, mainly the mandible, laryngeal cartilage, and skull, are frequently involved sites for ORN. A rare site for ORN is the hyoid, with very limited cases described in the literature. Recognition of the imaging pattern of hyoid ORN is critical to avoid misdiagnosis of recurrent disease, prompting early treatment.

Medication-related osteonecrosis and osteoradionecrosis of the jaws: Update and current management

Medication related osteonecrosis of the jaws (MRONJ) and osteoradionecrosis of the jaws (ORNJ) are two different diseases of quite similar appearance. MRONJ is mainly due to antiresorptive or antiangiogenic drug therapy and ORNJ to radiotherapy. The present work aimed at presenting and comparing the current knowledge on MRONJ and ORNJ. They both present as an exposure of necrotic bone and differ in some clinical or radiological characteristics, clinical course and mostly in treatment. They share similar risk factors. A tooth extraction is more frequently found as a triggering factor in MRONJ. The frequency of a maxillary localisation seems higher for MRONJ. On computed tomographic images, a periosteal reaction seems characteristic of MRONJ. More frequent pathological fractures seem to occur in ORNJ. It is mandatory, for ORNJ diagnosis, to exclude a residual or recurrent tumour using histological examination. Both MRONJ and ORNJ are challenging to treat and cannot be managed similarly. For both, it would still be worth to optimise awareness within the medical community, patients' oral hygiene and dental cares to improve their prevention and make their incidences decrease. Conservative therapy is more frequently achieved for MRONJ than ORNJ and surgical resection is more often performed for ORNJ. For both diseases, the last treatment possible in refractory cases is a surgical extensive resection with free flap reconstruction. A MRONJ classification is widely used today, whereas no consensus exists to date for ORNJ classification. We propose a classification that could play this role.

Preradiation tooth extraction and jaw osteoradionecrosis: Nationwide population-based retrospective study in Taiwan

OBJECTIVE

Radiotherapy (RT) for head and neck cancer (HNC) within 7 days of tooth extraction is contraindicated because it may increase the risk of osteoradionecrosis of the jaw (ORNJ). However, delayed RT could compromise survival in patients with HNC. By using a national healthcare database, we reviewed the contraindications and analysed other risk factors for ORNJ.

DESIGN

A retrospective cohort study.

SETTING

By using Taiwan's National Health Insurance Research Database, 5,062 HNC patients with at least one tooth extraction 1-21 days before the first RT day (index day) and without any extractions during or after RT from 2000 to 2013 were included. The patients were divided into two groups according to the time of tooth extraction before the index day: 1-7 days and 8-21 days.

PARTICIPANTS

Taiwanese patients with head and neck cancer.

MAIN OUTCOMES MEASURE

Univariate and multivariate Cox proportional hazard regression models were used to evaluate the risk factors of ORNJ.

RESULTS

The overall incidence of ORNJ in the included patients was 1.03% (mean follow-up duration, 4.07 ± 3.01 years; range, 1.00-13.99 years). Tooth extraction within 7 days before RT was not associated with increased ORNJ risk (hazard ratio [HR] =0.734; P = .312). Significant risk factors for ORNJ included oral cancer (adjusted HR = 3.961), tumour excision surgery within 3 months before RT (adjusted HR = 3.488) and mandibulectomy within 3 months before RT (adjusted HR = 5.985; all P < .001).

CONCLUSION

In a mean follow-up of 4 years, tooth extraction within 7 days before RT for HNC treatment did not increase the ORNJ risk compared with tooth extraction 7-21 days before RT.

Development of a Rat Model of Mandibular Irradiation Sequelae for Preclinical Studies of Bone Repair

Repairing mandibular bone defects after radiotherapy of the upper aerodigestive tract is clinically challenging. Although bone tissue engineering has recently generated a number of innovative treatment approaches for osteoradionecrosis (ORN), these modalities must be evaluated preclinically in a relevant, reproducible, animal model. The objective of this study was to evaluate a novel rat model of mandibular irradiation sequelae, with a focus on the adverse effects of radiotherapy on bone structure, intraosseous vascularization, and bone regeneration. Rats were irradiated with a single 80 Gy dose to the jaws. Three weeks after irradiation, mandibular bone defects of different sizes (0, 1, 3, or 5 mm) were produced in each hemimandible. Five weeks after the surgical procedure, the animals were euthanized. Explanted mandibular samples were qualitatively and quantitatively assessed for bone formation, bone structure, and intraosseous vascular volume by using micro-computed tomography, scanning electron microscopy, and histology. Twenty irradiated hemimandibles and 20 nonirradiated hemimandibles were included in the study. The bone and vessel volumes were significantly lower in the irradiated group. The extent of bone remodeling was inversely related to the defect size. In the irradiated group, scanning electron microscopy revealed a large number of polycyclic gaps consistent with periosteocytic lysis (described as being pathognomonic for ORN). This feature was correlated with elevated osteoclastic activity in a histological assessment. In the irradiated areas, the critical-sized defect was 3 mm. Hence, our rat model of mandibular irradiation sequelae showed hypovascularization and osteopenia. Impact statement Repairing mandibular bone defects after radiotherapy of the upper aerodigestive tract is clinically challenging. Novel tissue engineering approaches for healing irradiated bone must first be assessed in animal models. The current rat model of mandibular irradiation sequelae is based on tooth extraction after radiotherapy. However, the mucosal sequelae of radiotherapy often prevent the retention of tissue-engineered biomaterials within the bone defect. We used a submandibular approach to create a new rat model of mandibular irradiation sequelae, which enables the stable retention of biomaterials within the bone defect and should thus facilitate the assessment of bone regeneration.

Dental prevention of maxillo-mandibular osteoradionecrosis: A ten-year retrospective study

INTRODUCTION

Osteoradionecrosis (ORN) remains a frequent complication of radiotherapy in head and neck cancer. As ORN management is often complex, it is essential to focus on its prevention, mainly by dental prophylaxis. The objectives of this study were to evaluate a dental preventive approach based on ORN data and to highlight individual risk factors statistically associated with time-to-ORN.

MATERIALS AND METHODS

A retrospective study (January 2004-December 2013) included 415 patients with head and neck cancer who received radiotherapy in their treatment with at least 50 Grays on maxillo-mandibular bones. Pre-radiotherapy dental assessment (clinical and radiological) and prevention (with standardised extraction protocol) were performed.

RESULTS

The ORN rate was 7.5%, with a dental origin in 35.5% of cases, mainly represented by dental infection in exclusive mandibular locations. More than 90% of patients were partially or completely dentate, and more than 70% had poor oral hygiene. Dental extractions were performed in 67.9% of patients before radiotherapy and in 42.9% after radiotherapy. Statistically significant risk factors associated with time-to-ORN were addictions (tobacco and alcohol), diabetes, oropharyngeal tumour location, combination of surgery followed by radiotherapy and post-radiotherapy dental extractions.

DISCUSSION AND CONCLUSION

Considering that ORN implies severe disabilities and complex management, the rate of 7.5% is unacceptable. A better dental prevention could reduce this rate by one-third. Dental extractions could be systematic in high-dose irradiation mandibular areas in patients presenting with poor oral hygiene and/or statistically significant risk factors for the occurrence of ORN. Moreover, favourable oral condition after radiotherapy should be maintained.

Chinese expert group consensus on diagnosis and clinical management of osteoradionecrosis of the mandible

Osteoradionecrosis of the mandible (MORN) is one of the most devastating complications caused by radiation therapy in the head and neck region. It is characterized by infection and chronic necrosis of the mandible as the main manifestation. Clinically, MORN-related symptoms include swelling, pain, dysphagia, trismus, masticatory or speech disorders, refractory orocutaneous fistula, bone exposure, and even pathological fracture. MORN has become a challenging clinical problem for oral and maxillofacial surgeons to deal with, but thus far, this problem has not been solved due to the lack of widely accepted treatment algorithms or guidelines. Because of the nonexistence of standardized treatment criteria, most clinical treatment against MORN nowadays is largely based on controversial empirical understandings, while recommendations on post-therapeutic evaluations are scarce. Therefore, to further unify and standardize the diagnosis and treatment of MORN, to decrease the huge waste of medical resources, and ultimately, to improve the wellbeing of the patients, the Chinese Society of Oral and Maxillofacial Surgery (CSOMS) convened an expert panel specialized in MORN from 16 domestic medical colleges and affiliated hospitals to discuss the spectrum of diagnosis and and formulate treatment. In addition, consensus recommendations were also revised with a comprehensive literature review of the previous treatment experiences and research pearls. This 'expert consensus statement on diagnosis and clinical management of MORN' is for clinical reference.

Symptom distress and interference among cancer patients with osteoradionecrosis of jaw: A cross-sectional study

Objective

Osteoradionecrosis of the jaws (ORNJ) is among the most serious oral complications of head and neck cancer treatment with radiation therapy. This study aimed to examine the level of symptom distress and interference of ORNJ in head and neck cancer patients in China.

Methods

A cross-sectional study was conducted to profile patient reported symptom severity. Ninety-five hospitalized ORNJ patients were recruited. Participants completed the MD Anderson Symptom Inventory–Head and Neck Module-Chinese version.

Results

The percentage of participants who reported that they experienced at least one type of symptom was 97.9%, and 85.2% patients reported interference. The 10 most severe symptoms were as follows: limited mouth opening, problem with teeth/gums, difficulty swallowing/chewing, dry mouth, oral malodor, difficulty with voice/speech, dental ulcer, tinnitus/ear obstruction, skin pain/burning/rash, and difficulty hearing. The problem of limited mouth opening was more severe in patients with longer time to onset of ORNJ after radiotherapy. The interference of patients positively correlated with core symptoms (r = 0.612), head and neck symptoms (r = 0.709), and ORNJ symptoms (r = 0.440) (P < 0.01). The longer time to the onset of ORNJ after radiotherapy was positively and significantly correlated with symptom distress (r = 0.479, P < 0.001), and mouth opening correlated negatively with symptom distress (r = −0.298, P = 0.003).

Conclusions

ORNJ patients suffered mainly from limited mouth opening and other maxillofacial symptoms. The problem of limited mouth opening was more severe in patients with longer time to onset of ORNJ after radiotherapy. ORNJ patients commonly had symptom distress, which influenced their quality of life.

Osteoradionecrosis, an increasing indication for microvascular head and neck reconstruction

Better cancer treatment has led to a steadily growing population of cancer survivors suffering from late adverse effects after cancer treatment. The aim of this study was to investigate whether there has been an increase in free flap reconstruction due to osteoradionecrosis (ORN). A retrospective review was conducted to identify all consecutive head and neck free flap reconstructions performed over an 18-year period (1995-2012) at Karolinska University Hospital. A total of 235 free flaps were identified. Cases were divided into two groups: head and neck cancer reconstructions and ORN reconstructions. A comparison between the two groups showed longer survival (P<0.001) and higher rates of late complications (P<0.001) among ORN cases. ORN as an indication for reconstruction increased over time, from 7.0% of the total number of free flaps performed in 1995-2000, to 15.2% during the period 2001-2006, and to 27.3% in 2007-2012 (P<0.001). This, in accordance with the results of other studies, highlights the importance of the appropriate allocation of resources within the healthcare system to treat this patient group within the steadily increasing population of cancer survivors.

Osteoradionecrosis of the jaws triggered by dental implants placement: A case report

Background

The decision-making process about how to rehabilitate edentulous osseous defects in patients with head and neck cancer history can be complex. Even though, endosseous dental implants could be considered to be the first choice for treating these patients, it is highly important to be aware of the complications that might occur. The aim of this report was to describe the clinical features of mandibular fracture after dental implants placement on a cancer irradiated patient and update the available information about this event.

Case report

The case describes a 70-year-old man, with medical background of radiotherapy in jaw bones to treat a carcinoma in the floor of the mouth and later on in the soft palate and cheek. One week after dental implant surgery, the patient presented a mandibular osteoradionecrosis that healed in 8 months. A fracture on the right side of the body mandible was diagnosed one year after implant placement. Although several options were suggested in order to repair the fracture, the patient did not accept any further treatment despite the callus formation not being radiographically evident. The implant-supported prosthesis is functionally useful for more than 8 years of follow-up without significant problems.

Conclusions

The implant treatment and management of oncologic irradiated patients require special considerations due to the risk of osteoradionecrosis and its possible complications, such as pathologic fracture. It is necessary to provide full information to the patient about risk factors and complications.

Key words:Dental implants, mandibular fracture, osteoradionecrosis jaw, complications, fracture, cancer.

Nomogram model to predict postoperative infection after mandibular osteoradionecrosis surgery

Osteoradionecrosis of the mandible (ORNM) is one of the most dreaded complications of radiotherapy. The poor healing capacity of soft tissue after radiation may lead to surgical failure. The current study was designed to identify prognostic factors for postoperative infection (PPI) and propose corresponding prophylaxis and intervention protocols. A retrospective study was conducted concerning ORNM patients from 2000 to 2015. A risk-stratification score and nomogram model were established to predict the risk of PPI. A total of 257 patients were analyzed, and the total incidence of PPI was 23.3% (60/257). In multiple logistic regression analysis, radiation dose [Formula: see text]80 Gy (versus <80 Gy, OR = 2.044, P = 0.035, 95% CI: 1.05-3.979), bilateral ORNM (versus unilateral, OR = 4.120, P = 0.006, 95% CI: 1.501-11.307), skin fistula (versus none, OR = 3.078, P = 0.040, 95% CI: 1.05-9.023), and implant utilization (versus none, OR = 2.115, P = 0.020, 95% CI: 1.125-3.976) were significantly associated with PPI. The susceptibility to PPI in patients with risk-stratification scores of 14-22 was 2.833 times that of patients with scores of 7-13, and 7.585 times that of cases defined as scores of 0-6. The discrimination capability of the nomogram model was estimated using a ROC curve with an AUC of 0.708, revealing potentially useful predictive abilities. In conclusion, current risk-stratification scores and nomogram models effectively predicted the risk of PPI in ORNM patients.

Comparison of the incidence of osteoradionecrosis with conventional radiotherapy and intensity-modulated radiotherapy

BACKGROUND

Modern techniques of radiotherapy are supposed to decrease the incidence of osteoradionecrosis of the mandible (ORNM). The purpose of this study was to compare the incidence of ORNM after intensity-modulated radiotherapy (IMRT) in comparison to conventional 3D conformal radiotherapy techniques (conventional RT).

METHODS

We conducted a retrospective study of consecutive unselected patients treated in a single institution between 2002 and 2012. To minimize confounding effects, only patients with oropharyngeal carcinoma without surgery of the primary site were included.

RESULTS

The cohorts included 145 patients in the conventional RT group and 89 patients in the IMRT group. Total incidence rate of ORNM was similar for both groups with rates of 11% versus 10% (n = 16 for conventional RT and n = 9 for IMRT; p = 1.0). Subanalysis revealed more ORNM in T4 classified lesions with IMRT (p = .007). Analysis of different risk factors showed no statistically significant difference between ORNM and no-ORNM patients.

CONCLUSION

We found no reduction in ORNM with IMRT. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1708-1716, 2016.

Osteoradionecrosis of the Posterior Maxilla: A New Approach Combining Erbium: Yttrium Aluminium Garnet Laser and Bichat Bulla Flap

Osteoradionecrosis (ORN) of the jaw is a complication of radiation therapy for head and neck cancers. We report a case of ORN of the posterior maxilla treated with Er: YAG laser and a pedicled buccal fat pad (bichat bulla adipose) flap. A 69-year-old man presented complaining of pain on left maxilla. He had received high-dose radiotherapy (90 Gy) for squamous cell carcinoma of the left soft palate 2 years earlier. Clinical and radiographic examinations revealed ORN of the left maxillary molar region and maxillary sinusitis. Daily home care consisted of 0.9% saline irrigation and 0.8% H2O2 gel application. Sequestrectomy and tooth extraction were followed by debridement with Er: YAG laser and repair with a pedicled buccal fat pad flap. Complete resolution of ORN and maxillary sinusitis was established one year postsurgically. The excellent clinical outcome suggests that Er: YAG laser debridement and pedicled buccal fat pad flap are a viable option to treat ORN of the posterior maxilla.

Hydrogen-rich saline may be an effective and specific novel treatment for osteoradionecrosis of the jaw

Hydrogen, a therapeutic medical gas, can exert antioxidant activity via selectively reducing cytotoxic reactive oxygen species such as hydroxyl radicals. Hydrogen-rich saline is an alternative form of molecular hydrogen that has been widely used in many studies, including metabolic syndrome, cerebral, hepatic, myocardial ischemia/reperfusion, and liver injuries with obstructive jaundice, with beneficial results. Osteoradionecrosis of the jaw is a serious complication following radiotherapy for head and neck cancers. It has long been known that most radiation-induced symptoms are caused by free radicals generated by radiolysis of H₂O, and the hydroxyl radical is the most reactive of these. Reducing the hydroxyl radical can distinctly improve the protection of cells from radiation damage. We hypothesized that hydrogen-rich saline might be an effective and specific method of managing and preventing osteoradionecrosis of the jaw.

The Effects of Ionizing Radiation on the Oral Cavity

AIM

The aim of this study is to present a literature review on the effects of the ionizing radiation from radiotherapy treatment on dental tissues.

BACKGROUND

Among the effects of increasing global life expectancy and longevity of the teeth in the oral cavity, increasing rates of neoplastic diseases have been observed. One of the important treatment modalities for head and neck neoplastic diseases is radiotherapy, which uses ionizing radiation as the main mechanism of action. Therefore, it is essential for dentists to be aware of the changes in oral and dental tissues caused by ionizing radiation, and to develop treatment and prevention strategies.

RESULTS

In general, there is still controversy about the effects of ionizing radiation on dental structures. However, qualitative and quantitative changes in saliva and oral microbiota, presence of oral mucositis and radiation-related caries are expected, as they represent the well-known side effects of treatment with ionizing radiation. Points that still remain unclear are the effects of radiotherapy on enamel and dentin, and on their mechanisms of bonding to contemporary adhesive materials.

CONCLUSION

Ionizing radiation has shown important interaction with organic tissues, since more deleterious effects have been shown on the oral mucosa, salivary glands and dentin, than on enamel.

CLINICAL SIGNIFICANCE

With the increasing number of patients with cancer seeking dental treatment before and after head and neck radiotherapy, it is important for dentists to be aware of the effects of ionizing radiation on the oral cavity.

Dental implants in irradiated versus nonirradiated patients: A meta-analysis

The purpose of the present meta-analysis was to test the null hypothesis of no difference in dental implant failure rates, postoperative infection, and marginal bone loss for patients being rehabilitated by dental implants and being previously irradiated in the head and neck region versus nonirradiated patients against the alternative hypothesis of a difference. The study suggests that irradiation negatively affects the survival of implants, as well as the difference in implant location (maxilla vs mandible), but there is no statistically significant difference in survival when implants are inserted before or after 12 months after radiotherapy. The study failed to support the effectiveness of hyperbaric oxygen therapy in irradiated patients. It was observed that there was a tendency of lower survival rates of implants inserted in the patients submitted to higher irradiation doses. The results should be interpreted with caution because of the presence of uncontrolled confounding factors in the included studies.

Time interval after radiotherapy and dental implant failure: systematic review of observational studies and meta-analysis

BACKGROUND

Typically, dental implants are placed in irradiated bone after a delay that exceeds 6 months, but it is not known whether longer delays are beneficial.

PURPOSE

The purpose of the study is to review the literature comparing the failure rate of dental implants placed in irradiated bone between 6 and 12 months and after 12 months from the cessation of radiotherapy.

MATERIALS AND METHODS

Four electronic databases were searched for articles published until February 2013 without language restriction: Lilacs, Medline, Scopus, and the Cochrane Central Register of Controlled Trials. Two reviewers independently assessed the eligibility criteria and extracted data. Fixed effect meta-analysis was performed.

RESULTS

Overall, 3,749 observational studies were identified. After the screening of titles and abstracts, 236 publications were selected, and 10 were included in the final analysis. The pooled relative risk (RR) of failure was RRpooled  = 1.34 (95% confidence interval [CI]: 1.01-1.79), higher in individuals who had dental implants installed between 6 and 12 months after receiving radiotherapy. I(2) indicated nearly 21% heterogeneity (p = .25). Egger's test indicated no evidence of publication bias (p = .62); however, the removal of one study significantly affected the overall RR (RRpooled  = 1.08, 95% CI: 0.77-1.52).

CONCLUSIONS

Placing implants in bone within a period shorter than 12 months after radiotherapy may result in a higher risk of failure; however, additional evidence from clinical trials is needed to verify this risk.

Open versus closed reduction: comminuted mandibular fractures

PURPOSE

The purpose of the study was to review the literature regarding the evolution of current thoughts on management of comminuted mandibular fractures (CMFs).

METHODS

An electronic search in PubMed was undertaken in May 2012. The titles and abstracts from these results were read to identify studies within the selection criteria. Eligibility criteria included studies published in English or German reporting clinical series of CMFs.

RESULTS

The search strategy initially identified 409 studies. Fifteen studies were identified without repetition within the selection criteria. One case report article showing significance in the development of treatment techniques was included. Additional hand-searching yielded five additional papers. Thus, a total of 21 studies were included.

CONCLUSIONS

Open reduction and internal fixation (ORIF) in cases of CMFs are indicated in (a) severe injuries with significant displacement to allow restoration of pretraumatic anatomic relationships, (b) in the edentulous and semi-dentate patient, who may benefit from ORIF of CMFs when stable occlusal relationships are absent, and (c) in cases with multiple fractures of the midface, in which the mandible has to serve as a guide to reposition the midfacial bones. However, there is still a place for closed reduction/conservative treatment (CTR). ORIF in CMFs is not indicated in cases of minimally displaced comminuted fractures that could easily and adequately be treated with CTR. If the surgical team is not well versed in the nuances of rigid internal fixation, or the necessary equipment is not available, it is far better to do simple CTR. However, it would be more reasonable to refer the patient to a hospital that can provide means of ORIF in cases of clear indication of its use in CMFs. In cases where ORIF is indicated, stabilization by compression or any other form of load-sharing osteosynthesis is obviously contraindicated because small fragments cannot be compressed and are not capable of sharing loads. Thus, the ORIF of CMFs is best performed using load-bearing osteosynthesis; most experience has been gained with 2.7-mm reconstruction plates. External pin fixation could be used in cases when there is so much comminution, soft tissue disruption (mostly gunshot wounds), and there are inadequate teeth on either side of the comminuted fracture to control the spatial relationship of the remaining mandibular fragments with maxillomandibular fixation (MMF).

Myofibroblasts and their resistance to apoptosis: a possible mechanism of osteoradionecrosis

Osteoradionecrosis (ORN) in the head and neck area is the most devastating long-term complication of radiotherapy, with slow progression and inability to heal spontaneously. ORN can lead to intolerable pain, fractures, and sequestration of devitalized bone and fistulae, making oral feeding impossible and causing facial deformation. In spite of its notorious reputation over at least 90 years, the precise pathogenesis of ORN has not been fully clarified, which has led to obstacles in the management of the disease. Several theories about its pathogenesis have been formulated, and radiation-induced fibrosis is the newest one. According to this theory, ORN is essentially a type of fibrosis induced by radiotherapy, and antifibrosis therapy has been shown to be effective in its treatment. We assumed that ORN, like fibrosis in other organs, is the result of a process of fibrogenesis in which myofibroblasts are the key effector cells. The uninterrupted accumulation of myofibroblasts and consequent persistent excess production of collagenous extracellular matrix and tensile force result in loss of normal function and ultimately radiation-induced fibrosis. During this process, myofibroblasts may be protected from apoptosis by acquiring an immune-privileged capacity, which allows continuous matrix synthesis. If this hypothesis proves to be correct, it would enable better understanding of the cellular and molecular mechanisms underlying the pathogenesis and progression of ORN, and would help improve our ability to prevent occurrence of ORN, give an earlier diagnosis, and treat it more effectively.

Osteoradionecrosis: an update

Osteoradionecrosis (ORN) of the mandible is the most serious and severe side effect of combined treatment of head and neck tumors. A new theory for the pathogenesis of ORN has been proposed relating it to a fibro-atrophic mechanism including free radical formation, endothelial dysfunction, inflammation, microvascular thrombosis leading to bone and tissue necrosis. Risk factors mainly include radiation related risk factors, surgery and, tobacco and alcohol abuse. Removing of diseased teeth after and even probably after radiotherapy is generally considered the main risk factor in ORN. Conversely, steroid use before or after radiation may have a protective effect related to the inhibition of the initial inflammatory phase of ORN. Prevention of ORN is still based on the preventive extractions of decayed or periodontally compromised teeth before radiotherapy. Based on the current understanding of ORN pathophysiology, new preventive and therapeutic protocols have been suggested for mild to moderate stages. Free tissue surgical transfers is the treatment of choice of severe, extensive and long established ORN.