Aim:  Bone healing is impaired after irradiation, and implant surgery in irradiated mandibles is associated with lower implant survival compared with normal bone. The aim of this study was to investigate irradiated mandibular bone and implant stability and osseointegration in such compromised tissues. Materials and methods:  Thirty-one patients irradiated for head and neck cancer had 125 implants, one-stage with healing abutments installed as part of their oral rehabilitation. Bone biopsies were collected as part of the implant operation from 12 mandibles. All patients received adjunctive hyperbaric oxygen therapy pre- and post-operatively. Implant stability was measured during operation using a resonance frequency device, and for 16 patients, additional implant stability quotient (ISQ) values were recorded up to 20 weeks post-operatively. Results:  All bone biopsies showed radiation tissue injuries with focal necrosis and fibrosis. ISQ recorded at the time of operation showed values within normal range, with two thirds above 70. Sixteen implants (12.8%) were lost at an early stage (average of 3 months post-operatively), despite good initial stability. Sixteen patients with 63 implants were followed post-operatively for another 20 weeks. Thirty-seven implants (58.7%) showed ISQ values above baseline, whereas 26 implants (41.3%) had lower values. Soft-tissue problems with prolonged healing around the implants were observed in 12 patients, two of whom developed osteoradionecrosis. Conclusion:  Implant surgery in irradiated mandibles with poor bone quality is feasible but associated with increased soft-tissue complications and implant losses. The risk of such complications, however, is outweighed by the benefits of implants to enhance the outcome of oral rehabilitation of head and neck cancer patients. The dispersion of ISQ values makes implant loss in irradiated mandibles hard to predict from resonance frequency analysis alone.

BACKGROUND:Direct microscopy, anaerobic culture and DNA-DNA hybridization have previously demonstrated an association between microorganisms and osteoradionecrosis (ORN). The purpose of our study was to use culture independent molecular techniques to detect bacteria in necrotic bone lesions of the mandible after radiation therapy.DESIGN:Bacterial DNA was extracted from eight deep medullar specimens from resected mandibles (six cases), including one patient with relapse. 16S rRNA genes were PCR amplified, cloned, transformed into Escherichia coli and sequenced to determine species identity and closest relatives.RESULTS:From the analysis of 438 clones, 59 predominant species were detected, 27% of which have not been cultivated. The predominant species detected from radionecrotic mandibles were Campylobacter gracilis, Streptococcus intermedius, Peptostreptococcus sp. oral clone FG014, uncultured bacterium clone RL178, Fusobacterium nucleatum, and Prevotella spp. The study demonstrated intersubject variability of the bacteria present in ORN. In contrast to the diverse bacterial profile detected in primary infection, only a few members of the oral indigenous flora were identified from the relapse case.CONCLUSIONS:Diverse bacterial profiles in specimens of ORN in marrow spaces of the mandible were detected by culture independent molecular techniques. To better understand the pathogenesis and to improve the therapy of the infection, detection of all members of the complex bacterial flora associated with ORN is necessary.

Objective. To study the species and phenotypic characteristics of yeasts, i.e. colony morphology, biotypes, and biotype relatedness, and the oral distribution of yeasts, in thrush and denture stomatitis. Material and Methods. Yeast colony morphology was observed under a stereo-microscope and photographed with a digital camera. Genus, species, and biotypes of the yeast isolates were identified by using a commercial kit, ID 32C. Yeast biotype dendrograms were generated by Spotfire software and SPSS 15.0 for Windows. Results. Multiple colony morphologies were observed among the yeasts from both thrush and denture stomatitis. One genus, 6 species, and 21 biotypes were identified among the yeasts from thrush, while 2 genera, 7 species, and 20 biotypes were identified among the yeasts from denture stomatitis. Considerable similarities in predominant species, biotypes, and biotype clustering profiles were shown among the yeasts from thrush and denture stomatitis. However, Candida dubliniensis was identified exclusively in subgingival areas and biotype 7347340215 of C. albicans was identified more frequently in palate and sulci in thrush. Conclusions. A diversity of species and phenotypes was found among the yeasts in thrush and denture stomatitis. Candidal commensals were predominant in thrush and denture stomatitis, but the observation of divergent Candida species and biotypes, constituting 23% of all the yeast isolates, should not be ignored.

Osteoma is an uncommon benign neoplasm composed of mature bone and the growth is slow and continuous. The case of a 46-year-old man is presented. He presented with a large swelling on the left side close to the temporomandibular joint. He had suffered an accident with trauma to the head when he was 10-years. After another trauma at the age of 35 he was examined and a computed tomography revealed a radiopaque mass laterally to the left condylar neck. The osteoma gradually increased in size and resembled an ectopic condyle. The osteoma was removed surgically through an intraoral approach, and no recurrence has been observed.

Background/aim: Candida is an opportunistic pathogen. Understanding its genetic characters might increase our understanding of the pathogenesis of candidosis. We examined the genetic relationships of yeasts from the most common forms of oral candidosis: thrush and denture stomatitis.Methods: Yeasts were sampled from palate, buccal mucosa, gingival sulci/periodontal pockets and/or denture fitting surface of 19 thrush patients and 22 denture stomatitis patients. Random amplified polymorphic DNA and the Dendron computer-assisted program were used to determine the genotypic relatedness of the yeasts.Results: A dendrogram generated from 105 thrush isolates had similarity coefficients (S-AB) ranging from 0.58 to 1 with four clusters derived at S-AB 68%. Another dendrogram was generated from 91 isolates from denture stomatitis, with S-AB ranging from 0.59 to 1. Three clusters were established at S-AB 71%. In a composite dendrogram incorporating the thrush and denture stomatitis data and orally healthy data compiled from a previous study, five genotypic clusters were generated at S-AB 68%. Cluster II, the most dominant, comprised isolates from thrush, denture stomatitis and healthy conditions, while clusters III and IV contained yeasts mainly from thrush.Conclusions: Palatal yeast carriage was significantly increased in thrush and denture stomatitis, also after radiation, chemotherapy and denture wearing. The buccal mucosa was favorable for yeast colonization regardless of oral condition. Yeasts in thrush were more diverse than in conditions of oral health. The common clone (II) of infecting yeasts and commensals suggested that commensals could induce thrush and denture stomatitis, whereas the unique clones in thrush (III, IV) might have been established through strain replacement or maintenance with minor genetic variation.

PURPOSE:Mandibulotomy is a recognised surgical approach to tumours of the oral cavity and oropharynx. However, the nature and frequency of complications associated with this procedure varies in many studies. We report our experience with access osteotomies, with special reference to radionecrotic complications.PROCEDURES:A retrospective study of 18 consecutive patients undergoing planned mandibular osteotomies as part of the ablative surgery was performed. Various flaps were used for tissue closure: myocutaneous flap (n = 8), nasolabial flap (n = 1) and radial forearm free vascular flap (n = 6). Primary closure using remaining mucosa was achieved in 3 patients.RESULTS:Complete healing of the osteotomy was noted in 13 patients, and 5 patients (27%) developed major wound healing problems and osteoradionecrosis. Dental problems with resorption of the alveolar bone crest and loosening of the teeth adjacent to the osteotomy were seen in 7 patients (39%).CONCLUSIONS:Adequate soft-tissue closure is as important for a successful outcome as the type of osteotomy and fixation method applied. Extraction of the incisors is recommended for easier and safer tissue adaptation, especially when flaps are used for coverage and the osteotomy site will be included in the radiation field.

According to the current concept of osteoradionecrosis such tissue has become hypoxic, hypovascular and hypocellular and it has previously failed to show any bacterial growth. By using a molecular method, i.e., DNA-DNA hybridization, the presence of microorganisms in radionecrotic bone has formerly been demonstrated by us. The aim of the present study was to visualise bacteria in such bone by using scanning and transmission electron microscopy. Fourteen deep medullar specimens from resected radionecrotic mandibles were studied. Microorganisms were detected in 9 of the 14 samples (64%). The bacteria seen included rods, spirochetes and cocci, with rods being the predominant cells. One sample also contained yeasts (blastoconida and pseudohyphae). The data from this study strongly suggest an association between microorganisms and osteoradionecrosis. This may call for a revision of its presumed pathophysiology, including the possibility of an infectious etiology.

Bone necrosis secondary to radiation was previously attributed to trauma of devitalized bone and microbiological sepsis. However, conventional microbiological technique has failed to demonstrate microorganisms throughout osteoradionecrotic bone, claimed to be hypoxic, hypovascular and hypocellular. The aim of the present study was to examine such bone for bacteria using DNA-DNA hybridization. Compared to standard culture methods this technique enables the investigation of a vast number of bacteria in a fairly short time. Twelve deep medullary specimens from resected radionecrotic mandibles were studied. A multitude of bacterial species were detected, most of them anaerobic. Porphyromonas gingivalis was the most predominant organism, followed by Fusobacterium nucleatum subspecies polymorphum. All samples contained Actinomyces, Prevotella and F. nucleatum. The results of this study indicate that bacteria, particularly anaerobes, may play a more fundamental role in the pathophysiology of osteoradionecrosis than being merely surface contaminants.

OBJECTIVE:This retrospective study evaluates the results after orthognathic surgery in a group of patients with juvenile rheumatoid arthritis.METHODS:The material comprised sixteen patients where genioplasty with or without bilateral sagittal split (BSSO) had been performed during a 10-year period between 1991 and 2000. The patients were recalled for follow-up examination and the clinical records and radiographs of the patients were analysed.RESULTS:All patients reported an improved facial esthetics. Sixty-two% reported altered neurosensory dysfunction in the inferior alveolar nerve, but no patients reported altered feelings to interfere with function. Two patients reported reduction in pain in the TMJ from a score 10 and 7 in the VAS-scale preoperatively, to 0 after the orthognathic surgery. Eight of the patients reported this to be less uncomfortable compared to other surgical procedures because of their JRA. Ninety-four% noted a positive social change after the operation.CONCLUSION:Orthognathic surgical treatment of the JRA patient improves the facial profile. The described procedures are safe and serious complications were not seen in our study.

Purpose: By comparing our old (DP5, in use from 1978 to 1994) and new (Plato, Nucletron) dose planning system, we found that the old system underestimated doses by 20-25%. To study the possible consequences for the patients treated between 1978 and 1994, all who were still alive were invited to undergo an examination with respect to side effects and quality of life (QOL).Methods and Materials: The degree of overdosage was calculated by comparing the isodose distribution generated on the two dose planning systems. Eighty-four patients were then invited to undergo an examination with respect to side effects and QOL. The side effects were scored according to the LENT SOMA system and QOL according to European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30), and EORTC Quality of Life Questionnaire-Head & Neck 35 (QLQH&N35).Results: The mean overdosage of brachytherapy was 19.3%. No association was found between overdosage and side effects or QOL. For implants in the lateral border of the tongue, we found a statistically significant correlation between osteoradionecrosis and the following parameters: linear activity, total activity, dose rate, and extrapolated response dose. By multivariate analysis, only total implanted activity and the use of lead protection during brachytherapy were found to be of prognostic significance with respect to development of osteoradionecrosis.Conclusion: The incidence of side effects after brachytherapy at the Norwegian Radium Hospital seems to have been somewhat higher in the period under investigation than at other institutions. There may be several explanations, including the use of external beam radiotherapy before brachytherapy and departure from the Paris system among others. However, the side effects were not associated with the overdosage that was the basis for the study. As opposed to the general consensus of opinion, long-term QOL was found to be worse after brachytherapy than after external beam radiotherapy. This calls for increased awareness and a systematic prospective registration of the long-term side effects of brachytherapy. (C) 2002 Elsevier Science Inc.

Osteoradionecrosis of the mandible is a serious complication following radiotherapy of head and neck cancers. A retrospective study of 20 reconstructions of mandibular defects due to osteoradionecrosis was performed. Various osseocutaneous free flaps were used: upper lateral arm (n = 5), radial forearm (n = 1), iliac crest (n = 4) and fibula (n = 7). Four grafts had a condylar prosthesis, and for seven grafts fixation was accomplished with a reconstruction plate. In three patients the mandibular defect was reconstructed using a bridging plate only. We defined a successful reconstruction as a graft or plate that did not need removal. Success was noted in 15 out of 20 patients, giving an overall success rate of 75%. For the free grafts alone (n = 17), successful reconstruction was achieved in 15 patients (88%). Two fibular grafts were lost owing to exposure and infection, as well as all three alloplastic reconstructions. Minor postoperative complications were observed in 11 patients (58%).

Objective: To compare the difference in location and severity of osteoradionecrosis (ORN) of the mandible following either external beam irradiation alone or combined with brachytherapy in the management of orofacial cancer.Methods: CT was used to evaluate ORN in relation to the radiation source and field and the site of malignancy in 31 patients with orofacial carcinomas. Twenty-three patients received combined radiotherapy and brachytherapy and eight patients only external radiotherapy. The radiation dose distribution to the mandible was calculated retrospectively.Results: In the: combined radiotherapy group all patients had ORN of the lingual cortex, mostly adjacent to the position of previous iridium implants. Lingual defects were also found in the contralateral mandible in 35% of patients. Defects in the buccal cortex were seen in 30%. In the external radiotherapy group, ORN was found in both buccal and lingual cortices and 50% also in the contralateral mandible. When brachy therapy with iridium implants was used the dose to the buccal cortex was about one-third of that to the lingual cortex. There was no dose gradient between the cortices using external beam irradiation alone.Conclusions: Evidence of ORN was Found in both groups of irradiation regimens. Thus, the entire irradiated mandible should be considered as a compromised tissue at risk of ORN.

Purpose: Osteoradionecrotic bone has been characterised as hypovascular and metabolically inactive tissue with impaired perfusion. The present study was conducted to determine if dynamic contrast-enhanced MR imaging could provide additional information about the vascularity of radionecrotic mandibular bone. Material and Methods: Dynamic contrast-enhanced MR imaging was performed on 10 patients with mandibular osteoradionecrosis (ORN), and on 6 patients, irradiated for oropharyngeal tumours, without symptoms or signs of ORN. Nine patients in the ORN group received a series of 20 hyperbaric oxygen (HBO) treatments, after which the dynamic MR investigation was repeated. Results and Conclusion: Radiation per se did not lead to increased contrast enhancement, whereas all patients with ORN showed marked contrast enhancement of the osteoradionecrotic bone marrow. After HBO treatment, pathological contrast enhancement of the abnormal bone marrow could still be seen, but the rate of enhancement was less than before in 7 of 9 patients. Two patients had an increase in the enhancement rate. The findings suggest the existence of an increased and patent microvasculature.

We have retrospectively studied 73 patients with mandibular osteoradionecrosis (ORN) following radiotherapy (high voltage external beam radiation alone, or combined with brachytherapy) ranging from 50 to 130 Gy (mean 76) with fields including the mandible. Based on this analysis we defined four distinctive stages: Stage 0: mucosal defects only; Stage I: radiological evidence of necrotic bone with intact mucosa; Stage II: positive radiographic findings with denuded bone intra-orally; Stage III: clinically exposed radionecrotic bone, verified by imaging techniques, along with skin fistulas and infection. The clinical features and characteristics of these stages are described, along with their clinical courses and outcome. The incompleteness of current ORN definitions, mainly emphasizing mucosal defects and bone exposure, and the need for a revised ORN classification is pointed out. Based on these observations and the insufficiency of previous definitions, we arrived at the following ORN definition: Radiological evidence of bone necrosis within the radiation field, where tumour recurrence has been excluded.

OBJECTIVES To compare the value of computed tomography (CT) with panoramic radiography in the diagnosis and presurgical evaluation of mandibular osteoradionecrosis (ORN). METHODS Retrospective study comparing the diagnostic information from CT and panoramic radiography of 33 patients with clinical symptoms of ORN. In six patients the imaging was compared macroscopically with the resected mandible. RESULTS Both panoramic radiography and CT revealed ORN in 31 cases. In 22 the anterior-posterior extent of the lesions could be estimated with equal reliability. In six patients the lesion appeared larger on CT and in three on panoramic radiography. Mono- or bicortical destruction, central necrosis and sequestration were better visualized by CT. Comparison between the imaging findings and the surgical resection showed that CT depicted the topography of the specimen more accurately. CONCLUSIONS CT is superior to panoramic radiography in visualizing the features of mandibular ORN and the anterior-posterior extent of the lesion.

We undertook a microradiographic study in osteoradionecrotic mandibular bone to estimate the number of vascular channels in the compact bone, number of resorption areas, and number of regeneration areas. Normal mandibles had a similar number of vascular channels/vision field compared with compact bone in other parts of the body. Irradiation itself did not significantly alter this number. After osteoradionecrosis had developed in the mandible, the number of vascular channels increased (p = 0.02). Treatment with hyperbaric oxygen further increased the number of vascular channels/vision field (p < 0.003). The normal mandible had no resorptive or regenerative areas, either before or after radiotherapy. The osteoradionecrotic mandible, however, had an increased number of resorptive as well as regenerative areas/vision field. Fluorescence as an indication of incorporation of tetracycline was seen in the regenerative areas of all osteoradionecrotic specimens treated with doxycycline. The process started from the vascular channels, periosteum, and endosteum. We conclude that the compact bone of mandibular osteoradionecrosis has high metabolic activity with active resorption and regeneration of bone and the limitation of the blood supply through cortical vascular channels, seems to be only one of many important factors.

Since 1989, 40 free-tissue grafts were used in 39 patients to repair defects following major head and neck ablative surgery (n = 32) and for reconstruction of the mandible because of osteoradionecrosis or trauma (n = 7). The radial forearm flap was used in 17 patients (five including a segment of radius), the lateral arm flap in seven, fibula in five and a segment of ileum for restoration of the hypopharynx in 11 cases. Three radial forearm flaps and the bone in one lateral arm flap failed. Better functional and cosmetic results seem to be obtained with free flaps than with other reconstructive techniques.