Genotypic relatedness of yeasts in thrush and denture stomatitis.

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.

Scanning and transmission electron microscopy demonstrates bacteria in osteoradionecrosis.

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.

DNA-DNA hybridization demonstrates multiple bacteria in osteoradionecrosis.

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.

Mandibular osteotomies in patients with juvenile rheumatoid arthritic disease.

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.

Mandibular osteoradionecrosis: reconstructive surgery.

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%).

Osteoradionecrosis of the mandible. Comparison of the effects of external beam irradiation and brachytherapy.

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 brachytherapy 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.

Mandibular osteoradionecrosis: clinical behaviour and diagnostic aspects.

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.

Dynamic MR imaging of mandibular osteoradionecrosis.

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.

Osteoradionecrosis of the mandible: a microradiographic study of cortical bone.

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.

Mandibular osteoradionecrosis: a comparison of computed tomography with panoramic radiography.

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.

[Free vascular grafts in reconstructions in the head and neck region]. / Frie vaskulariserte transplantater ved rekonstruksjoner i hode- og halsregionen.

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.