[Contribution and limitations of MIS(®) screwed expanders in the jaws: illustration from clinical cases and comparison of the osseous volume from three-dimensional radiographic pictures]. / Intérêts et limites des expanseurs vissés de MIS(®) aux maxillaires : illustration à partir de cas cliniques et comparaison du volume osseux à partir de clichés radiographiques tridimensionnels.

INTRODUCTION: Implanting on an atrophic maxilla alveolar ridge may require bone augmentation. Screwed expanders may sometimes be used, thus avoiding a more invasive bone graft. It allows bone density to increase and results in alveolar ridge expansion, by using bone elasticity and adaptation, allows the optimization of the available bone volume, with low morbidity. TECHNICAL NOTE: Despite its apparent simple implementation, the technique should be adapted to each type of bone so as to optimize results. We present two clinical cases, use of screwed expanders, their action on the crestal bone, and the limitations of this technique depending on ridge configuration. DISCUSSION: Screwed expanders are non-traumatic easy-to-use tools. They can be inserted like implants because they have a good self-tapping effect. Their use is more secure in narrow spaces; they are more comfortable for the patient than impacted expanders use. They allow increase of cancellous bone density, which improves primary stability in case of low density bone. Bone volume preservation and avoiding bone grafts can shorten the implant treatment procedure and decrease costs for the patient. Unfortunately, this technique does not allow alveolar ridge height increase. If this is required, onlay graft or guided tissue generation are the best alternatives.

Database analysis of a French type 2 diabetic population shows a specific age pattern of tooth extractions and correlates health care utilization.

AIMS: To assess the relationship between type 2 diabetes and tooth loss and the predictive value of health behavior and routine dental care in regard to both dental and medical follow-ups. METHODS: Cross-sectional study from a national database of a French population of railways transport workers was conducted with a descriptive analysis between registered diabetic patients and non-diabetic subjects. The relationship between oral health and diabetes was measured by tooth extraction prevalence in regard to the frequency of scaling-prophylaxis sessions and the number of medical and dental appointments. RESULTS: The prevalence of tooth extractions in the type 2 diabetic population is 1.88 higher than the non-diabetic population. Diabetic patients tend to undergo dental extractions earlier and more often than non-diabetic individuals. They also have more medical appointments and less dental check-ups and scaling sessions than the non-diabetic population. CONCLUSION: Measured by tooth loss, type 2 diabetic patients have a significantly earlier detrimental oral status when compared to the non-diabetic population. They exhibit a different pattern in health care utilization of outpatient medical resources. Oral health surveillance is not correctly addressed by the medical and dental coverage of these diabetic patients. Emphasis should be directed on specific dental care programs aimed at preventing tooth loss.

[Chemotherapy and dental growth]. / Chimiothérapie et croissance dentaire.

A prospective study about the development of the mandibular second right molar, has been performed with 17 chemotherapy treated children in the Paediatric Oncology department of the Centre Oscar-Lambret (Lille). Our method is based upon the measure of the crown or root length for different periods: periods with or without chemotherapy. These measurements have been performed every 6 months for 18 months with orthopantomograms. We notice for both the crown and the root: a significant difference in growing speed between periods with an without chemotherapy; a speeding up of the mineralization at the end of the treatment rejoining the average figures of a healthy test population.

[Dental anomalies following anticancer chemotherapy]. / Anomalies dentaires après chimiothérapie anticancéreuse.

Chemotherapy administered during childhood may induce dental abnormalities, such as acquired amelogenesis imperfecta, microdontia, hypodontia and altered root morphology. The magnitude of the defect varies according to the cytotoxic agents, the duration of their use and the stage of tooth development at the time of chemotherapy. Patients who received high-dose chemotherapy before the age of 5 are particularly concerned. The dental supervision of these children is based upon three orthopantomograms: the first one has to be performed before starting chemotherapy and will be used as a reference; the second is done soon after the drug therapy in order to evaluate the first consequences; the third is performed after the eruption of all permanent teeth (age 12-13 in average) in order to determine the dental abnormalities. In case of hypodontia, orthodontic treatment must be considered, but it is necessary to take into account the fact that it may increase the risk of root resorption. Preventive dental care is important for these children. It involves meticulous oral hygiene and frequent dental visits to assess and maintain dental health.

[Mesoscopic anatomy of the peribuccal facial muscles]. / Anatomie mésoscopique des muscles faciaux péri-buccaux.

In 16 human face dissections under the operative microscope, the authors recall the classical anatomy of perioral muscles. Instead of the 3 muscles around the nostrils, they prefer to discern two layers: deep and superficial. The subnasal region can similarly be dissociated. Resuming the commissural node study they insist upon the peculiar role of the platysma muscle and its expansions, and upon the tight imbrication of buccinator and orbicularis oris muscles.

[Giant-cell reparative granuloma: a case report]. / Granulome réparateur central à cellules géantes (GRCCG).

We report a case of giant-cell granuloma located in the maxilla of a 9-year-old child. The pathogenesis of giant-cell reparative granuloma (GCRG) remains obscure. Radiological features are variable. Radiolucency or well or ill-defined uni-or multilocular aspects with trabeculations can be observed. Symptoms of compression on the adjacent tooth's root and pathology findings confirm the diagnosis. Curettage is effective and recurrence is rare.

[Cleaning implantation burs. Observations using scanning electron microscopy]. / A propos du nettoyage des forets implantaires. Observation en microscopie electronique a balayage.

Drastic aseptic conditions are necessary in implantological treatments. A good sterilizing procedure of the specific instrumentation, like drills, is based on an efficient cleaning. Because of their design, the cleaning of drills is a real challenge. The aim of this investigation is to evaluate two different cleaning procedures usually used by implantologists. One is based on a manual cleaning, the other on an ultra-sonic cleaning. The instrument observed by scan-electron-microscope, is a I.T.I. system drill. The results show the superiority of the ultra-sonic cleaning. The manual cleaning is especially ineffective on the inside and the cutting part of the drill. Even if ultra-sonic cleaning is definitely a better procedure, it has to be improved. A extensive study should be conducted to optimize the cleaning parameters, if not, single-use drill should be definitely preferred by implantologists.

Preliminary results and evidence of early regeneration in inferior alveolar nerve fibers.

Inferior alveolar nerve (IAN) damage can occur in trauma, cyst enucleation, sagittal split osteotomy or third molar removal, and the consequences are a loss of sensation to the mandibular teeth, gingiva and lower lip. Because of its anatomical position in a bony canal, IAN suture is rarely evoked. The aim of this study was to demonstrate the reality of IAN regeneration by using electrophysiological and histological methods after experimental section and suture of this nerve in rabbits. Nine adult female animals were used for the experiments. Six months after section and suturing using 10.0 nylon with a conventional technique, electrical stimulation of the nerve was performed to record electrophysiological activity. Each rabbit was its own reference. In each case, an action potential was recorded after microsurgical repair and definitively suppressed by section of the nerve. Morphometric analysis showed a decrease in the number of nerve fibers in the operated nerve versus the control nerve. The histological study showed an increase in nerve fibers with a cross-sectional area of 19-36 and 37-73 micro m(2) and a decrease in the smaller fibers (2-4 and 5-7 micro m(2)). This preliminary study confirms the possibility of nerve regeneration in rabbits 6 months after section and conventional suturing.

[A technic using MRI. A comparative study of 3 anesthetic technics of the inferior alveolar nerve]. / Approche en I.R.M. D'une etude comparative de 3 techniques d'anesthesie du nerf alveolaire inferieur.

In our study we used M.R. sectional imaging in the axial and coronal planes to investigate three alveolar nerve anaesthesia techniques: Gow Gates, Akinosi and Classical techniques. Furthermore, anatomic sections were made using cadaveric specimens in axial and coronal planes to visualize anatomical relations of the anaesthetic drug. The present study showed the more or less important and quick spreading of the anaesthetic drug through the infra temporal area depending on the anaesthesia technique. Possible incidents are also discussed.

[Raman spectrometry applied to calcified tissue and calcium-phosphorus biomaterials]. / Spectrometrie raman appliquee aux tissus calcifies et aux biomateriaux phospho-calciques.

The rigid part of the human body consists essentially of carbonated apatite (calcium phosphate). Biologists don't have any tools to study this "mineral" phase, though its origin is organic. A new approach of some compounds like enamel or bone is obtained with the Raman micro-characterisation by a very fine analysis of chemical bonds in a micrometric scale. This method allows the characterisation, the analysis and the dosage of ions, like carbonate, acid phosphates, proteins and fatty acids. The identification of other organic or mineral compounds (e.g. calcium carbonate, calcium oxide, substitutant ions...) is also possible. The Raman microspectrometry can also be used to study the chemical and physical properties of biomaterials and their evolution after implantation in a dental or bone site. On synthetical calcium phosphate, beta-TCP, brushite and hydroxyapatite can be distinguished and the impurities found in plasma spray deposits can be measured. The detection of alpha-, beta-, or gamma-pyrophosphates could be obtained in some commercial beta-TCP. The Raman microspectrometry is the only non-destructive method which allows the identification of the chemical bonds in a micrometric scale and gives the "fingerprint" of the studied component.