Treatment of dentin hypersensitivity with a combination of nano- fluorhydroxyapatite and Nd:YAG laser

The aim of this study was to evaluate a new treatment modality of dentin hypersensitivity combining nano-fluor-hydroxyapatite [NFH] and Nd:YAg laser and to compare its effect with other therapies such as cyanoacrylate and sodium fluoride using scanning electron microscope. Sixty freshly extracted human premolar teeth were collected. The coronal portion of each tooth was removed and the canals were instrumented and obturated with gutta-percha. A 3 mm wide ring of root surface was cut with a rotary instrument to expose the underlying dentin. Teeth were randomly separated into six groups of ten teeth each: 1] combination of NFH and Nd:YAG laser; 2] Nd:YAG laser; 3] NFH; 4] desensitizing cyanoacrylate resin bonding [Tetric N Ceram]; 5] 2% sodium fluoride; 6] control group. The topography of each group after treatment was determined by scanning electron micro graph. The percentage of occluded tubules was calculated by dividing the total number of occluded tubules by the total number of tubules in each photomicrography. The highest occluding effect of dentinal tubules was obtained for the combination of NFH and Nd: YAG laser [99.8 +/- 3.3%]. However, no significant difference was found among groups 2 [83.1 +/- 5.2%], 3 [82.3 +/- 4.4%], 4 [82.1 +/- 7.2%] and 5 [81.4 +/- 3.5%] [p>0.05]; these treatment modalities showed similar occluding effect on dentinal tubules. The use of NFH and Nd:YAG laser was beneficial for closure of exposed dentinal tubules compared to other treatment modalities. This approach could be promising for dentin hypersensitivity treatment

novel nano-calcium carbonate-polyurethane-based root canal obturation material: synthesis and evaluation of some physical properties

The aim of this study was to prepare a new root canal obturation material named "nano-calcium carbonate-polyurethane" and to evaluate three of its physical properties which are solubility, water sorption and radiopacity. Polycarbonate 1, 6-hexamethylene diisocyanate, NCO 49.79%, and 1, 4-butanediol were mixed together to form polycarbonate-based thermoplastic polyurethane [TPU[. Additive materials like nano-calcium carbonate powder, zinc oxide, calcium hydroxide and barium sulfate with different ratios were blend together with the polycarbonate-based thermoplastic polyurethane to form the final obturation material. The nano-calcium carbonate-polyurethane was found to be a promising root canal filling material; the percentages of solubility, water sorption and radiopacity were consistent with ISO standards

Evaluation of the microleakage of different class V cavities prepared by using Er: YAG laser, ultrasonic device and conventional rotary instruments with two dentin bonding systems: an in vitro study

The aim of this study was to evaluate the extent of microleakage in class V cavities prepared with bur, Er: YAG laser and ultrasonic, hybridized with two different bonding agents ["Single bonding", a solvent-free bonding agent, and "Swiss TEC SL bond", an alcohol-based solvent]. Thirty freshly extracted human premolars were divided into three groups of ten teeth each according to the device used in cavity preparation: Group 1] Er:YAG laser [500 mJ, 10 Hz, 63.69J/cm 2]; group 2] ultrasonic device and group 3] diamond burs. On each tooth, two cavities were prepared, one on the buccal surface and one on the lingual surface. Each group was subdivided into two subgroups of 5 teeth each according to the bonding system used: subgroup a] "Single bonding" and subgroup b] "Swiss TEC SL bond]. Cavities were restored with a micro-hybrid composite resin. After thermocycling, the specimens were immersed in 2% methylene blue solution for four hours and then sectioned in the buccolingual direction. Dye penetration was scored using a stereomicroscope. The two-way ANOVA test and paired t-test revealed no statistically significant differences among the methods of preparation [conventional, laser and ultrasonic]. However, statistical differences were found between the adhesive tested; the "Single bonding" had lower microleakage values than "Swiss TEC SL bond". Based on the results of this study it can be concluded that the Er: YAG laser and ultrasonic device are as effective as the conventional method in preparing cavities. The extent of microleakage depends on the type of the bonding agents

new concept in hybridization bromelain enzyme for deproteinizing dentin before application of adhesive system

To assess the deproteinizing effect of bromelain enzyme and compare it with Nd:YAG laser and 10% NaOCl by using scanning electron microscope SEM and polarized microscope. Sixty extracted human upper premolars were selected to be given standardized buccal and lingual class V cavities. The teeth were divided into three groups each one consisted of twenty teeth. Thirty teeth were recruited for SEM study and the other thirty for polarized microscope. Group 1: Teeth were deproteinized with Nd:YAG laser, group 2: Teeth were deproteinized with bromelain enzyme and group 3: Teeth were deproteinized with 10% NaOCl. Application of bromelain enzyme has led to removing collagen network and significantly decreased the global leakage scores of the adhesive system