Objective: The aim of this study was to evaluate the effect on dentinal surfaces of diode lasers (810 and 980 nm) at different parameters. Materials and methods: Twenty-four caries-free human impacted wisdom teeth were used. The crowns were sectioned transversely in order to expose the dentin. The smear layer was removed by a 1 min application of ethylenediaminetetraacetic acid (EDTA). Each surface was divided into four quadrants irradiated at a different output power setting for each kind of laser: 0.8, 1, 1.6, and 2 W (energy densities: 2547, 3184, 5092, and 6366 J/cm 2 , irradiation speed 1 mm/sec; optical fiber diameter: 200 lm; continuous and noncontact mode). Half of the samples were stained with a graphite paste. All specimens were sent for scanning electron microscopic (SEM) analysis. Pulp temperature increases in additional 20 teeth were measured by a thermocouple. Results: Diode laser irradiations at 0.8 and 1 W led to occlusion or narrowing of dentin tubules without provoking fissures or cracks. The application of graphite paste increased the thermal effects in dentin. Measurements of pulp temperature showed that irradiations at 0.8 and 1 W for a period of 10 sec in continuous mode increased pulp temperature (T £ 2°C). Conclusions: Diode lasers (810 and 980 nm) used at 0.8 and 1 W for 10 sec in continuous mode were able to seal the dentin tubules. These parameters can be considered harmless for pulp vitality, and may be effective in the treatment of dentinal hypersensitivity.

Objective: The aims of this in vitro study were to evaluate: (1) the influence of 5% NaOCl application on Er:YAGirradiated dentin; and (2) its effect on the quality of adaptation of the composite restoration margins. Background data: Previous research has shown that Er:YAG dentin irradiation produces a thermally affected tissue layer that results in lower bond strength than that of nonirradiated dentin. The removal of this thermally-affected layer may enhance the quality of dentin bonding Materials and methods: Forty-nine caries-free extracted human molars were transversely sectioned in order to totally expose the dentin. Four standardized cavities were created on the dentinal surface of each molar. First, two cavities were irradiated with Er:YAG laser (2.94 nm): 150 mJ, 10 Hz, variable square pulse (VSP) mode (100 lsec), beam diameter = 0.9 mm, speed of irradiation = 1 mm/sec, 20% air and 20% water. Then, one of irradiated cavities and one of nonirradiated cavities were treated for 30 sec with 5% NaOCl solution. Finally, they went through a standard bonding treatment for composite restoration, etching, bonding, and composite filling. We obtained four groups of cavities: (1) one control group of nonirradiated cavities not pretreated with NaOCl; (2) one group of nonirradiated cavities, pretreated with NaOCl; (3) one group of irradiated cavities, not pretreated with NaOCl; and (4) one group of irradiated cavities, pretreated with NaOCl. All samples were subjected to thermocycling. Every cavity was immersed into a 0.5% solution of methylene blue. The percentage of dye penetration (microleakage) in the composite-dentin interface was evaluated. Six molars were analyzed by scanning electron microscope. Results: Dye infiltration depth was significantly reduced in irradiated cavities treated with 5% NaOCl solution. Conclusions: The application of a 5% NaOCl solution on Er:YAG irradiated cavities can significantly improve the marginal quality of composite bonding.

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Résumé -Introduction : L'ostéochondromatose ou chondromatose synoviale temporo-mandibulaire est une arthropathie chronique bénigne d'étiologie inconnue. Elle se caractérise par une métaplasie chondroïde de la membrane synoviale ayant pour résultat la formation intra-articulaire de corps cartilagineux ou ostéo-cartilagineux. Observations : Quatre cas d'ostéochondromatose synoviale de l'ATM sont envisagés : le premier exhibait un tableau clinique similaire à celui d'un désordre temporo-mandibulaire (DTM) ; quant aux trois autres, ils furent diagnostiqués à la suite d'une tuméfaction de la région prétragienne. Discussion : Cette pathologie se révèle par des signes articulaires similaires à ceux d'un DTM. Un bilan radiologique par tomodensitométrie ou par imagerie par résonance magnétique permet d'évoquer le diagnostic. Le traitement est l'ablation des corps étrangers. L'évolution est favorable avec un faible taux de récidive. Conclusion : Les signes cliniques aspécifiques compliquent le diagnostic de cette pathologie. La confrontation des éléments cliniques, radiologiques et histologiques permet de poser le diagnostic.Abstract -Synovial chondromatosis of the temporomandibular joint: 4 case reports and literature review. Introduction: Synovial osteochondromatosis or chondromatosis of the Temporomandibular Joint (TMJ) is a benign arthropathy of unknown etiology that is characterized by chondrometaplasia of the synovial membrane, resulting in multiple intra-articular cartilaginous bodies. Observations: We present four cases of this disorder: the first case presented signs and symptoms of TMJ disorder and the other three presented a preauricular swelling. Discussion: Patients usually present articular symptoms similar to those related to TMJ disorders. Imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) are used for the diagnosis. Treatment of synovial chondromatosis usually consists of removal of the intra-articular bodies. The recurrence rate is low. Conclusion: Aspecific articular symptoms complicate the diagnosis of this pathology. The diagnosis is made by assessing the clinical, radiological and histological findings.