Patricia A. Tordik

An agar diffusion comparison of the antimicrobial effect of calcium hydroxide at five different concentrations with three different vehicles.

The purpose of this study was to determine if varying the percent (by weight) of aqueous calcium hydroxide or using different vehicles had an effect on its antibacterial efficacy against common endodontic pathogens in a pour plate/traditional streak agar diffusion model. Mixtures of calcium hydroxide powder and sterile saline in 40, 50 and 60 percent concentrations and the commercial preparations UltraCal XS and Vitapex were tested against six known endodontic pathogens with an agar diffusion method. Each medicament was placed in one of five wells, in each of 10 agar plates (n = 10), for cultures of each bacterial species. Zones of inhibition were measured after 48 hours incubation for aerobes and 96 hours incubation for anaerobes. Multiple one-way analyses of variance and post-hoc Student Neuman Keuls evaluated the data at alpha = 0.05. Larger zones of inhibition were consistently observed for higher concentrations of calcium hydroxide with statistical significance among the bacteria, particularly between 40% and 60%. Vitapex had significantly smaller zones of inhibition than all other medicaments and 35% UltraCal XS with methylcellulose was nearly as effective as 50% Ca(OH)(2) in inhibitory activity. Formulations containing 50-60% Ca(OH)(2) or 35% Ca(OH)(2) with aqueous methylcellulose are recommended as endodontic interappointment medicaments.

Effect of Dentin Thickness on Root Surface Temperature of Teeth Undergoing Ultrasonic Removal of Posts

The purpose of this study was to measure root surface temperature changes on thin-rooted and thick-rooted teeth undergoing ultrasonic vibration of cemented posts, with and without irrigation. Twenty-four single canal teeth were decoronated, length standardized, instrumented, obturated, and cemented with prefabricated posts. The teeth were divided into thin-rooted or thick-rooted groups. Thermocouples were cemented to the external proximal root surfaces adjacent the post ends. The roots were then mounted in standardized plaster molds and placed in a temperature-controlled water bath. Posts were ultrasonically vibrated with and without irrigation, and external root temperatures were recorded from an initial 37 degrees C baseline for a period of 4 minutes. The data were analyzed with the Student t test at alpha = .05. No significant differences were found in temperature change between the thin-rooted and thick-rooted groups, with or without irrigation. Linear regression and correlation analysis revealed no relationship between dentin thickness and temperature change.

Quantitation of catecholamines in inflamed human dental pulp by high-performance liquid chromatography.

Catecholamines may play an important role in the control of intrapulpal pressure as mediators of vasoconstriction. A baseline level of catecholamines (dopamine, epinephrine, and norepinephrine) in the uninflamed human dental pulp was previously reported using high-performance liquid chromatography. The purpose of this study was to compare the level of catecholamines present in the inflamed human dental pulp with the baseline level established in virgin teeth. Twelve uninflamed pulps were analyzed as a control and to validate previous findings. Pulp tissue was obtained from 10 vital and inflamed teeth requiring endodontic treatment. Selective criteria for each patient included: absence of systemic disease, medications, and allergies; a vital response to ice, heat, and electric pulp tests; and periodontal probing < or = 3 mm. A prior history of pain associated with the tooth was an additional criterion for inflamed pulps. To avoid the presence of an exogenous catecholamine, local anesthesia without epinephrine was administered. Dopamine, epinephrine, and norepinephrine were chemically extracted and analyzed by high-performance liquid chromatography with ultraviolet detection. Catecholamine levels found to be present in the pulp during inflammation were greater than the baseline level established in uninflamed pulp tissue.

Effect of EDTA preparations on rotary root canal instrumentation.

INTRODUCTION The aim of this study was to evaluate whether rotary instrumentation using saline, EDTA 17% solution, or RC-Prep (Premier Dental, Philadelphia, PA) resulted in differences in root canal transportation. The secondary objective was to assess if instrumentation using these agents caused changes in the working length and canal volume. METHODS Moderately curved mesiobuccal roots of 24 maxillary molars were standardized in length and randomized into 1 control and 2 experimental groups. The canals were instrumented with 0.04 taper rotary files to size #30. All groups were irrigated with saline. Group 1 was also irrigated using EDTA 17% solution (Pulpdent Corp, Watertown, MA), and in group 2, RC-Prep was used. X-ray micro-computed tomographic scans and working length measurements were made before and after instrumentation. Three-dimensional models were created from the pre- and postinstrumentation scan data and compared for volume changes. Centroid points were calculated in cross-sectional slices of the canals, and transportation was determined by measuring the distance between the pre- and postinstrumentation points. The data were analyzed with 1-way analysis of variance (α = 0.05) and the Tukey post hoc test. RESULTS Less transportation was observed in group 2 than in group 1 (P = .001) and the control group (P = .014). Transportation in group 1 and the control group was not significantly different. Canal volume in group 1 was increased relative to group 2 (P = .004) and the control group (P = .022). No significant differences in the working length were observed. CONCLUSIONS The use of chelating agents during root canal instrumentation did not significantly increase apical transportation.