[Prosthetic rehabilitation after osteonecrosis of the jaws due to histiocytosis X and treatment with bisphosphonates apropos of a case]. / Réhabilitation prothétique après ostéonécrose des maxillaires due à une histiocytose X et un traitement aux bisphosphonates à propos d'un cas.

Bisphosphonates are involved in the occurrence of Osteonecrosis of Jaws (ONJ), which is a complication of these treatments. This osteonecrosis concern the alveolar bone and develops generally after an oral surgery. It can however occur spontaneously without preliminary dental extraction. Other risk factors could play potentiates the risk of ONJ. This osteonecrosis results in an osseous exposure in patient treated or having been treated by bisphosphonates, without any cervico-facial irradiation. Actually, no treatment has been the proof of its effectiveness. Preventives measures of ONJ in oral cavity are the best method before, during and after administration of bisphosphonates. In this article, we present the clinical case of a patient with histiocytois treated by bisphosphonates and having developed ONJ. The selection criteria of the prosthetic rehabilitation as well as the techniques used are detailed.

Effects of high doses of ionising radiation on bone in rats: a new model for evaluation of bone engineering.

The purpose of this study was to assess the effects of high doses of ionising radiation on the histology and healing of bone in an experimental model of 12 inbred rats. Ten of the rats had external irradiation of a single dose of 30 or 45 Gy on the hind limbs, which is equivalent to 2 or 3 times the routine doses used for treatment in humans. Three weeks later, two bony defects were created on their left sides, and the animals were killed 12 or 18 weeks after irradiation. Decalcified bony specimens were studied with light microscopy for qualitative analysis. Thirty Gy irradiation induced medullar oedema or fibro-oedema and normal or fibrous healing of the defects. Forty-five Gy induced medullar oedema or fibro-oedema and depletion in bone marrow. In addition, pathological healing of the defects was obvious and characterised by oedema, fibrosis, and necrosis. In this study high doses of ionising radiation modified the histology of bone, particularly into fibro-oedema, and delayed healing. This new animal model could be used to evaluate the capacities of tissue-engineered materials to repair bony defects after irradiation and osteoradionecrosis.

[Gingival lichen planus]. / Le lichen plan gingival.

Lichen planus (LP) is a chronic inflammatory disease of uncertain etiology. When the gingiva is affected, the LP can appear under several clinical forms. The diagnosis of the gingival lichen planus is based on the anamnesis, the clinical observation and the histological analysis. Various medicamentous and non medicamentous treatments are used to treat gingival LP with random results, due to the lack of knowledge on the etiology and the recidiving character of the lesions. The risk of malignant transformation of gingival LP is weak but it depends on clinical forms, justifying a periodic follow-up of all patients.

[Desquamative gingivitis]. / La gingivite desquamative.

The desquamative gingivitis is the clinical term given to the gingival manifestation of mucocutaneous diseases. It is characterized by an erythematous, glazed, friable and hemorrhagic gingiva, which can be accompanied by pains. Except the gingiva, the lesions can be localised on other oral mucous membranes or on the skin. The three principal diseases at the origin of the desquamative gingivitis are by order of frequency: the cicatricial pemphigoïd, erosive lichen planus and pemphigus. The knowledge of the clinical, histological and immunohistochemical characteristics of these three affections is essential for the diagnosis and the suitable treatment of the desquamative gingivitis.

Carpegen real-time polymerase chain reaction vs. anaerobic culture for periodontal pathogen identification.

BACKGROUND/AIMS: The aim of this study was to compare two methods of microbiological diagnosis, anaerobic bacterial culture and real-time polymerase chain reaction (PCR), for the detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Fusobacterium nucleatum, and Treponema denticola. METHODS: Seventy-two samples were collected from 18 patients who were suffering from aggressive periodontitis. The data obtained were compared for the two methods. RESULTS: The results obtained with real-time PCR were different from those obtained with bacterial culture. The detection differences were 3% for A. actinomycetemcomitans, 8.33% for P. intermedia, and 12.5% for F. nucleatum. However, the differences for P. gingivalis and T. forsythia were 51.39% and 36.11%, respectively. No comparison was possible for T. denticola because it cannot be identified in culture. The variations found were the result of the better detection level (10(2) pathogens) of the PCR probe. Unlike bacterial culture, PCR allows the detection of T. denticola, which does not forming colonies and is oxygen sensitive. For F. nucleatum, T. forsythia and P. gingivalis, the real-time PCR technique was more sensitive than culture. CONCLUSION: Good results were obtained with the real-time PCR technique for the six periopathogens targeted. This method seems to be indicated for its simplicity, rapidity and reproducibility but it cannot analyze data for an antibiotic susceptibility test. The periodontist must therefore choose one of these two methods according to his specific clinical objective: to obtain rapid, specific detection even with weak initial concentrations (but for targeted periopathogens only) or to be non-specific and analyze the pathological activity with an antibiogram.

[Social vulnerability of out-patients consulting the dentistry service of a public hospital]. / Vulnérabilité sociale des consultants d'odontologie d'un hôpital public.

There are social inequalities in oral and dental health. It can be useful to identify people in socially vulnerable or marginalised situations because they require a particular kind of care. Through a survey of patients in a dentistry services in a public hospital, we sought to identify those people in a precarious socio-economic situation by the use of a tool designed and validated by multi-disciplinary experts. The tool includes five criteria, and is presented in the format of an index card which is filled in by the patient upon his arrival. This data collection was carried out in two distinctly separate period of time (winter and summer). 865 cards were collected, and the rate of collection of complete data was 73%. 94% of the cards allowed us to determine the socio-economic status of the patient, and 48% (n=382) of them were classified as having a socially vulnerable situation. Among them, 69% of them benefited from CMU or AME, and 59% of them do not have any supplementary health insurance. 47% of them admit to having difficulties in paying for their medications or covering the cost of their medical consultations, and 48% perceive a social service aide. The prevalence of social vulnerability of the dental centre's patients is estimated at 32%. This data collection tool has made it possible to measure the significance and the nature of the social vulnerability of the patients who receive care and services from this public hospital's dentistry unit. Its capacity to identify patients whose care needs are often not met remains to be seen, as well as the capacity of the hospital to make up for these lost opportunities thus remains to be highlighted.

[Comparative metric study of the edentulous dental arch in black Africans and white Europeans]. / Etude métrique comparative de l'arcade mandibulaire de l'édente total noir Africain et du blanc Europeen.

The current 89 samples comparative study shows that the mandible arch is different statistically in Blacks and Whites populations. African Blacks mandible dimensions are superior considering both inter retromolar tubercles measurements and the arch length. Therefore, the impression trays manufacturing should be reconsidered for Blacks prosthetic rehabilitation.

[Committee on cancer of the upper aerodigestive tract and survey on buccodental aspects. Report of 164 teams]. / Comité de cancérologie des VADS et prise en compte des aspects bucco-dentaires. Enquête auprès de 164 équipes.

BACKGROUND: Head and neck cancer occupies an important place in the field of oncology in France (8%). Patient management requires a wide diversity of treatment modalities and must be based on a multidisciplinary approach. MATERIALS AND METHODS: This clinical ethics study was based on analysis of a national survey of current practise in public and private hospital structure. A 28-questions anonymous questionnaire was send to 164 practitioners caring for these patients from the stage of diagnosis and evaluated the modalities of dental treatments and the related ethical aspects. RESULTS: The competence of the various practitioners in their respective fields is undeniable, but there is a lack of multidisciplinary collaboration. The absence of an oral practitioner is a serious problem and can reduce the patient's chances of cure. DISCUSSION: The oral practitioner must participate in head and neck cancer committees at all steps of treatment in order to provide curative, preventive care and prosthetic rehabilitation, thereby contributing to improvement of the quality of life of these patients.

Immunohistochemical localization of type IV collagen and laminin (alpha1) in denture stomatitis.

Chronic clinical irritation of the palatal mucosa by dentures involves a series of histological changes in epithelial and connective tissues, inflammatory cells and the vasculature. No single change is pathognomic of this inflammatory process. The rupture of basement membrane associated with the development of denture stomatitis often marks an important stage. This study investigated modifications in basement membrane organisation, especially the distribution of type IV collagen and a specific laminin chain (alpha1), during denture stomatitis. Biopsies of palatal mucosa were obtained from 12 patients (8 with denture stomatitis and 4 with clinically healthy mucosa) who had worn removable dentures for more than 3 years. Immunohistochemical studies performed with specific antibodies to type IV collagen and a laminin (alpha1) revealed strong expression in the basement membrane of healthy palatal mucosa. In denture stomatitis, some discontinuities or disruptions in basement membrane were observed at the interface between connective tissue and epithelial cells. These findings suggest a relationship between the expression of laminin (alpha1) and type IV collagen and the development of denture stomatitis, a disorder involving modification of soft tissues in which initial inflammation of the palatal mucosa results from stress under the denture. These changes in basement membrane can be detected by histological studies.

Biological activities of sustained polymyxin B release from calcium phosphate biomaterial prepared by dynamic compaction: an in vitro study.

Calcium phosphate ceramics (CaP) have recently been proposed as a potential matrix for a bioactive drug delivery system (DDS) in which the effect in situ of a released therapeutic agent is favored by the biocompatibility, osteoconductivity, and bioresorption of the ceramic material. Polymyxin B (PMB) is a polypeptidic antibiotic which undergoes thermodamage above 60 degrees C. The dynamic compaction method was developed to consolidate the drug load on CaP powder without external heating. Two projectile velocities (50 and 25 m/s) were used here to achieve powder consolidation. Among the different techniques used to associate therapeutic agents with CaP, wet adsorption was performed before the dynamic compaction process. The PMB release profile was measured by a capillary electrophoresis technique, CaP crystallography was studied by x-ray diffraction, and CaP physicochemical analysis was performed by infrared spectroscopy. The biological activities of PMB-loaded compacted CaP were determined by the effect of the antibiotic and monocyte/macrophage degradation on compact surfaces. PMB release began after 2-3 days of incubation for blocks compacted at 25 m/s velocity and on day 5 for those compacted at 50 m/s velocity. A discrepancy was noted between the amounts of PMB released (0.5-2.1 mg) and the amounts initially compacted (2-8 mg) with CaP powder. The biological activities (antibacterial activity and inhibited lipopolysaccharide effects on monocyte/macrophage CaP degradation) of PMB released from compacted calcium-deficient apatite were unaltered. Thus, dynamic compaction allows PMB to be used with CaP ceramics without any loss in its integrity and biological effects.

Polymyxin B inhibits biphasic calcium phosphate degradation induced by lipopolysaccharide-activated human monocytes/macrophages.

Numerous cell types, such as monocytes and osteoclasts, are involved in calcified matrix degradation. In this context, calcium-phosphate ceramics present similar degradation processes in vivo and in vitro to those found in a natural calcified substrate. As the monocyte/macrophage lineage is among the first cells to appear in ceramic implantation sites, it is a key protagonist in inflammatory reaction and biodegradation mechanisms. This study investigated the ability of human monocytes/macrophages activated by various agents [lipopolysaccharides (LPS), polymyxin B (PMB)] to degrade biphasic calcium-phosphate ceramics. PMB sulfate is a bacteriostatic antibiotic that modulates LPS-induced cell activities in vivo and in vitro. Degradation pits (about 10 microns) produced on the pellet surface by these monocytes were discrete, with well defined margins. LPS increased the degradation of calcium-phosphate ceramic (number of lacunae, mean pellet surface area degraded) in a dose-dependent manner whereas polymyxin B downmodulated it significantly. The addition of 2 micrograms/mL of polymyxin B reduced the number of degradation lacunae and the extent of degraded surface area induced by 0.1 microgram/mL LPS by 87% and 64%, respectively. Thus this cell culture system can be very useful in the study of cellular degradation of biomaterials and of the influence of therapeutic agents that may modulate these cell activities.

[Microvascular mandibular reconstruction and implantology. A study of the stability of long-term results, apropos of 2 cases followed for 8 years]. / Reconstruction mandibulaire microvascularisée et implantologie. Etude de la stabilité des résultats à long terme, à propos de deux cas suivis à 8 ans.

The objective of this study was to determine the long term stability of implants on mandibles reconstructed by microvascular bone transfer. We present two cases of mandible reconstruction, the first one was performed after tumor resection and the second one after gunshot injury. The reconstructions were performed by iliac crest osseous and osteocutaneous free flaps and the mean follow-up period was 8 years. The implant was an IMZ Titanium and a classic prosthetic system was used. No complication was observed (mucous ulceration, infiltration around the implant), and the feared friction phenomenon between the neo mucosa and the reconstructed bone has not been a problem for long term follow-up.