A prospective case series in regenerative endodontics: The effective use of diluted antibiotic hydrogels in endodontic regeneration procedures.

Objective: to investigate the effectiveness of diluted antibiotic hydrogels in endodontic regeneration procedures. Materials and Methods: One conventional treatment (calcium hydroxide) and two experimental treatments containing 1 mg/mL antibiotic in gel (MC-TAP and MC-DAP) were prepared for this study. The effect of these medicaments on the proliferation and differentiation potential of dental pulp stem cells (DPSCs) was examined before their clinical use, using WST and ALP assays. Twenty-two teeth diagnosed with necrotic immature roots were treated with calcium hydroxide, MC-TAP or MC-DAP using the endodontic regeneration protocol as described by the American Association of Endodontists (AAE). Teeth were examined after application of the medicament, at the time of regeneration and after 12-24 months. Results: All treated teeth showed resolution of signs and symptoms shortly after treatment with the different medicaments. However, signs and symptoms returned a few months after initial treatment in clinical cases treated with MC-DAP. All successfully treated teeth examined after 12-24 months were free of signs and symptoms, but vitality was not achieved. Conclusion: Low concentration antibiotic gel containing triple antibiotic paste (MC-TAP) can be successfully used for endodontic regeneration procedures.

Effect of gender on performance of undergraduate dental students at the University of Jordan, Amman.

The purpose of this study was to see if gender-based differences exist in the performance of dental students at the University of Jordan (UJ), Amman. The retrospective analysis included data from two groups of students: 413 fourth-year dental students (178 males and 275 females) from four consecutive years (2005 through 2008) and 357 fifth-year students (128 males and 229 females) who graduated in the years 2005 to 2008. The influence of gender on the results of the fourth-year students in six theoretical and six clinical courses and the cumulative GPAs of the fifth-year students were studied. In both theoretical and clinical fourth-year courses, multivariate analysis of variance (MANOVA) revealed significant main differences in raw scores between the two gender groups. Female students were significantly better in five theoretical courses. In clinical courses, female students outscored male students in pediatric dentistry and prosthodontics, male students outperformed female students in conservative dentistry and orthodontics, and no significant gender differences were seen in oral surgery and fixed prosthodontics. The cumulative GPAs of the female graduated students were significantly higher than those of the male students. The results showed a significant relationship between gender and academic performance of dental students for these classes. The reasons for these findings should be further investigated.

A palladium-free gallium-based alloy: analysis of composition and microstructure.

OBJECTIVES: To study the microstructure of a palladium-free gallium-based alloy (Galloy) before and after mixing to identify the metallic phases produced by the setting reaction and assess the quantitative elemental analysis of the phases present. METHODS: The Galloy powder was analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the particle size distribution was determined using a high resolution particle size analyzer. Cylindrical test specimens were mechanically condensed in accordance with ISO 1559: 1986 for XRD, energy dispersive spectroscopy (EDS) and SEM analyses of the set alloy. Disc shaped specimens were prepared by manual condensation to compare the width of the reaction zone with specimens condensed mechanically. RESULTS: The Galloy powder consisted of spherical particles varying between 0.1 and 40 microm in diameter which contained a network of grooves and clefts extending deep within the substance of the particles. The reaction zone appeared 'grainy' and 'fragmented' compared with the well defined reaction zone previously observed for Pd-containing gallium-based alloys. The student t-test indicated the width of reaction zone varied significantly (P<0.001) with method of specimen fabrication.Significance. The significantly larger reaction zone in the manually condensed specimens was possibly due to failure of the condensation technique to force out excessive liquid alloy present in the triturated mass. The surface topography of the Pd-free Galloy powder particles could be responsible for the characteristically fragmented and ill-defined reaction zone observed in the set material compared with the well defined reaction zone previously observed for Pd-containing gallium-based alloys.

The effect of thermocycling on microleakage of several commercially available composite Class V restorations in vitro.

STATEMENT OF THE PROBLEM: Microleakage is a major factor contributing to the occurrence of secondary carious lesions around composite restorations. PURPOSE OF STUDY: This in vitro study investigated the effect of thermocycling on microleakage of several composite Class V restorations. MATERIAL AND METHODS: One hundred twenty molars were randomly distributed into 6 groups of 20 teeth. Class V preparations were made in the buccal and lingual surfaces of each tooth and restored in bulk by use of 6 composites (Arabesk, Silux-Plus, Solitaire 2, Durafill VS, Charisma, and Renew) according to the manufacturers' recommendations. The teeth were stored in distilled water at room temperature for 24 hours. The teeth in each group were divided randomly into 2 subgroups: (a) thermocycled for 500 cycles between 5 degrees and 55 degrees C with a dwell time of 30 seconds, (b) no thermocycling treatment. All restored teeth were immersed in 1% methylene blue dye for 4 hours and sectioned buccolingually with a diamond wheel. Dye penetration was scored by use of a stereomicroscope at original magnification x4. The generalized linear models statistical analysis was used (alpha=.05). RESULTS: The preparation margins (enamel/dentin) and thermocycling had a significant effect on microleakage (P=.0351, P<.0001, respectively); the type of material had no significant effect (P=.1689). CONCLUSIONS: Thermocycling significantly increased the microleakage (P<.0001). The overall microleakage at the enamel margins was significantly less than at the dentinal margins (P=.0351).