Clinical efficiency of a natural resin fluoride varnish (Shellac F) in reducing dentin hypersensitivity.

Previous in vitro permeability and scanning electron microscopic studies have demonstrated the effectiveness of a new natural based-resin varnish (Shellac F) in dentin permeability reduction and effective tubule occlusion. The aim of this randomized double-blind, controlled, split mouth 8-week clinical study was to evaluate the efficiency of Shellac F in reducing dentin hypersensitivity. Ten patients (eight women: two men) completed the study. A quadrant including at least one hypersensitive tooth (Visual Analog Scale - VAS = 15 mm to air blast) was considered as a unit and randomly assigned to different groups for Shellac F, Duraphat, Isodan. Three applications of each material were completed at days 0, 1 and 7. The subjective response was assessed by tactile and thermal/evaporative methods. Data were collected at baseline and after the first application, at 15 min, 1, 7, 14, 28 and 56 days. Analysis was based on Kruskall-Wallis test, Wilcoxon signed rank test and the method of the least square means. No statistically significant difference was noted between Shellac F and the two control materials. Regardless of the type of stimulus, Shellac F showed significant immediate and progressive continuous efficiency in reducing dentin hypersensitivity until 56 days (VAS of 14 +/- 12 mm and provoking pain force of 89 +/- 12 cN, respectively, compared with 38 +/- 23 mm and 41 +/- 10 cN at baseline), corresponding to a highly effective relief dentin hypersensitivity. Shellac F reduced dentin hypersensitivity and did not differ from the two desensitizing agents used as controls.

The use of a resorbable membrane in mucogingival surgery. Case series.

A surgical technique involving a resorbable membrane was used to treat 3 to 7 mm localized human buccal recessions on 10 consecutive patients. The exposed root surface was scaled and a trapezoidal mucoperiosteal flap was elevated after de-epithelization of the papillae. The space between the root and the membrane was created using a bur to form a concavity on the root and by bending the membrane with a suture. The flap was positioned as coronally as possible covering the membrane. The sutures were removed 15 days postsurgery and tetracycline therapy prescribed for 10 days. The results were evaluated at 12 months. The surgical procedure resulted in a significant reduction in recession (2.9 mm +/- 1.3) as well as a gain in attachment (3.4 mm +/- 2.1). Calculation of mean root coverage was 59.6%. There was no significant change of the keratinized tissue width. For therapeutic reasons, re-entry was performed in 2 cases: newly formed tissue was observed on the previously exposed roots. Guided tissue regeneration using a resorbable membrane appears to provide good results in cases of localized buccal recession.

Cutting efficiency of a mid-infrared laser on human enamel.

In this study, the cutting ability of a newly developed dental laser was compared with a dental high-speed handpiece and rotary bur for removal of enamel. Measurements of the volume of tissue removed, energy emitted, and time of exposure were used to quantify the ablation rate (rate of tissue removal) for each test group and compared. Cutting efficiency (mm3/s) of the laser was calculated based on the mean volume of tissue removed per pulse (mm3/pulse) and unit energy expended (mm3/J) over the range of applied powers (2, 4, 6, and 8 W). The specimens were then examined by light microscopy and scanning electron micrographs for qualitative analysis of the amount of remaining debris and the presence of the smear layer on the prepared enamel surface. Calculations of the cutting efficiency of the laser over the range of powers tested revealed a linear relationship with the level of applied power. The maximum average rate of tissue removal by the laser was 0.256 mm3/s at 8 W, compared with 0.945 mm3/s by the dental handpiece. Light microscopy and scanning electron micrograph examinations revealed a reduction in the amount of remaining debris and smear layer in the laser-prepared enamel surfaces, compared with the conventional method. Based on the results of this study, the cutting efficiency of the high-speed handpiece and dental bur was 3.7 times greater than the laser over the range of powers tested, but the laser appeared to create a cleaner enamel surface with minimal thermal damage. Further modifications of the laser system are suggested for improvement of laser cutting efficiency.

Comparison of the intraosseous biocompatibility of Vitremer and super EBA by implantation into the mandible of rabbits.

OBJECTIVES: This study compared the intraosseous biocompatibility of Vitremer, a new hydrophilic glass-ionomer cement, to that of Super EBA. STUDY DESIGN: Twenty-two New Zealand rabbits were anesthetized, the mandibular bone exposed, and two holes were drilled through the cortical plate. The materials were loaded into silicone carriers and inserted into the mandibles. Eleven rabbits were killed 4 weeks after implantation, 11 animals after 12 weeks. The mandibles were prepared with standard histologic procedures; the tissue reactions were graded from none to very severe. RESULTS: At 4 weeks Vitremer implants showed very slight to slight reactions, and the Super EBA implants showed slight reactions and one moderate reaction with no significant difference between the two materials. At 12 weeks, bone healing had occurred, despite the persistence of some fibrous tissue interposition. The reactions were classified as none to very slight for Vitremer and very slight to slight for EBA. Statistical analysis showed better results for Vitremer at 12 weeks. CONCLUSION: The intraosseous biocompatibility of Vitremer was similar at 4 weeks and superior at 12 weeks to that of Super EBA. Its other properties should be evaluated before considering its use in clinical practice.

[Modification of the level of adenosine triphosphate in digital pulp capillary blood in patients with microcirculatory disorders following i.v. injection of coenzyme A (CoA 1000)]. / Modification du taux d'adénosine tri-phosphate (ATP) dans le sang capillaire prélevé au niveau de la pulpe digitale, dans les troubles de la microcirculation, après injection i.v. de coenzyme A (CoA 1000).

Capillary blood ATP assay was performed in 2 groups of patients (diabetic and non-diabetic) with disorders of microcirculation, before and several minutes after 2 mg I.V. of Coenzyme A (CoA 1000). Values obtained showed a significant increase in both groups. The hypothesis advanced, based on previous experimental data indicating an action of CoA on intracellular calcium movement, is that CoA 1000 acts by elevation of the membrane ATP/Ca+ ratio of red corpuscles, and possible activation of their deformability and flow rate in the microcirculation.

Quantitative evaluation by glucose diffusion of microleakage in aged calcium silicate-based open-sandwich restorations.

This study compared the in vitro marginal integrity of open-sandwich restorations based on aged calcium silicate cement versus resin-modified glass ionomer cement. Class II cavities were prepared on 30 extracted human third molars. These teeth were randomly assigned to two groups (n = 10) to compare a new hydraulic calcium silicate cement designed for restorative dentistry (Biodentine, Septodont, Saint Maur des Fossés, France) with a resin-modified glass ionomer cement (Ionolux, Voco, Cuxhaven, Germany) in open-sandwich restorations covered with a light-cured composite. Positive (n = 5) and negative (n = 5) controls were included. The teeth simultaneously underwent thermocycling and mechanocycling using a fatigue cycling machine (1,440 cycles, 5-55°C; 86,400 cycles, 50 N/cm(2)). The specimens were then stored in phosphate-buffered saline to simulate aging. After 1 year, the teeth were submitted to glucose diffusion, and the resulting data were analyzed with a nonparametric Mann-Whitney test. The Biodentine group and the Ionolux group presented glucose concentrations of 0.074 ± 0.035 g/L and 0.080 ± 0.032 g/L, respectively. No statistically significant differences were detected between the two groups. Therefore, the calcium silicate-based material performs as well as the resin-modified glass ionomer cement in open-sandwich restorations.

An experimental technique to repair cracked teeth using calcium phosphate, melted by a laser beam: an in vitro evaluation.

Using a neodymium: yttrium-aluminum-garnet laser beam to seal vertical root fracture lines with tricalcium phosphate paste represents an alternative treatment for cracked teeth with noted clinical results. This article describes a study of the permeability of molten crystals of hydroxyapatite in the dentin of a cracked root after crack lines have been filled with a preparation of tricalcium phosphate melted by a neodymium: yttrium-aluminum-garnet laser beam. The morphology of the sealed cracks was analyzed under a scanning electron microscope that showed a deep fusion of tricalcium phosphate along crack lines.

[Hormones and venous system]. / Hormones et système veineux.

Sex hormones have an effect on venous "content" and "container" according to their chemical nature, their dosage and their mode of administration: 17 beta-estradiol (endogenous): protective effect; synthetic estrogens, at normal or low doses: thrombogenic; oral natural estrogens: thrombogenic; extra-digestive natural estrogens: non thrombogenic; non steroid progestagens (androgenic): thrombogenic; non androgenic progestagens: non thrombogenic. Clinically, the venous disease si characterized by sudden episodes occurring at key-periods of the hormonal life: puberty, pregnancy, menopause, oral contraceptives intake, substitute treatments of menopause, premenstrual syndrome. Evaluation of these different situations shows that an early treatment is possible and needed, which, although not providing a new venous wall for these constitutionally fragile patients, may act effectively at two levels: 1) correction of the haemodynamic disorder (venous reflux in the saphenous arches and the perforators; 2) resorption of tissue infiltration. As primary prevention, in a patient with hormonal disorders or who must be treated with estrogens or progestagens, the objective of our treatment is to protect the venous wall and encourage the return circulation. One must: 1) reinforce the vaso-constrictive effect and the parietal tone, 2) limit collagen and elastin alteration, 3) reinforce capillary permeability and decrease the interstitial edema, 4) normalize the haemorheological constants, 5) restore the balance hemostasis-fibrinolysis. The opinion of a phlebologist seems essential before prescribing a hormonal treatment and monitoring the effects of the treatment. Cooperation between gynaecologists and phlebologists is particularly essential in the interpretation of the clinical disorders as well as discussing the venous risk, the dosage and the administration route of sex hormones.