James R. Jensen

A comparison of methods used in root canal sealability studies

The purpose of the study was to compare several methods that have been used to assess marginal leakage of root canal fillings. Sixty-three extracted, single-rooted teeth were instrumented and filled in a standardized manner. Teeth were randomly divided into groups of twenty and exposed to solutions containing methylene blue dye, calcium-45, carbon-14-labeled urea, and iodine-125-labeled albumin for 48 hours to compare the degree of leakage indicated by each technique. Methylene blue dye was found to penetrate farther up the canal than any of the isotope tracers. Carbon-14-labeled urea penetrated farther than the calcium-45- or iodine-125-labeled albumin. The mean volume of solution penetrating the teeth was exceedingly small (0.0011 ml) and probably unimportant physiologically.

An evaluation of the use of amalgam, Cavit, and calcium hydroxide in the repair of furcation perforations.

The purpose of this study was to compare the clinical, radiographic, and histo[ogic changes that occur in response to three of the most commonly used materials to repair furcation perforations. The results of the experiment showed that amalgam was superior to Cavit and calcium hydroxide as a sealing material of furcation perforations. The most severe reactions occurred in the control group where the perforations were not filled.

Endodontic recall radiographs: How reliable is our interpretation of endodontic success or failure and what factors affect our reliability?

Three hundred thirty cases were selected from an endodontic practice. Postoperative and recall radiographs of each case were examined by four endodontists for an interpretation of treatment success or failure. One hundred eighteen cases were examined a second time by each endodontist. Initial analysis showed substantial inconsistency in both inter- and intraobserver interpretation. The cases were then categorized by average radiographic density differences within radiograph sets, anatomic location of the treated tooth, technical compatibility within radiograph sets, and by length of time between postoperative and recall radiographs. It appears that these factors do not affect reliability of success/failure interpretation.

Microleakage of composite resin and amalgam core material under complete cast crowns

Ninety extracted human teeth were used to compare the microleakage of composite resin over, amalgam core, and regular crown preparations under a complete cast gold crown cemented with zinc phosphate cement as determined by 2% fluorescein dye solution. Specimens were compared with and without aging after cementation in a thermal bath by cycling some of them between 4 degrees C and 60 degrees C in a 2% fluorescein dye bath and others in a similar bath held at 37 degrees C. Fluorescein dye (under ultraviolet light) demonstrated microleakage of the specimens between the crown-tooth interface and the core-tooth interface. There were no significant differences in the microleakage due to aging. The specimens held at 37 degrees C in the fluorescein dye bath showed no significant differences between the core preparations and the regular crown preparations. However, when specimens were thermally cycled between 4 degrees C and 60 degrees C, there were significant differences. With thermal cycling, the regular crown preparations were better able to resist microleakage at the crown-tooth interface than either the composite resin core or the amalgam core preparations. The results of this investigation seem to indicate a need for further evaluation of core build-ups under cemented complete gold crowns.

An in vitro study of the comparative effectiveness of obturating curved root canals with gutta-percha cones, silver cones, and stainless steel files

The quality of apical seal obtained with gutta-percha cones, silver cones, and stainless steel files was assessed in 120 freshly extracted teeth with moderately or severely curved root canals. Teeth were coated with wax, except in the apical foramen area, and immersed in 2 percent methylene blue solution for 48 hours. Apical leakage was quantitated by a linear measurement of the distance that the dye penetrated along the root canal and by a volumetric measurement of the quantity of dye within the root. There was a highly significant (p less than 0.001) correlation between the two measurements. Root canals filled with silver cones showed significantly less apical leakage than those filled with gutta-percha or stainless steel files, regardless of degree of curvature. For both silver cones and stainless steel files, leakage was less in severely curved roots than in moderately curved roots.

The Influence of Adalimumab on the Healing of Apical Periodontitis in Ferrets

Introduction Given the increasing use of anti–tumor necrosis factor &agr; (anti‐TNF&agr;) biologic medications, and their interferences with the immune‐inflammatory response, this study evaluated the effect of adalimumab (anti‐TNF&agr;), on healing and healing time of apical periodontitis (AP) in ferrets. Methods Twelve male ferrets received cone beam computed tomography of the jaws at baseline health (T0); AP confirmation (T1); and 30 (T2), 60 (T3), and 90 (T4) days after root canal treatment (RCT) to monitor healing. All animals had AP induced in the canines; 3 ferrets (12 teeth) provided the positive controls for the histologic evaluation; 9 ferrets were randomly divided into 3 treatment groups with 12 teeth each in the following manner: Systemic: conventional RCT and systemic anti‐TNF&agr;; Local: RCT and periapical administration of anti‐TNF&agr; before canal obturation; conventional RCT only (control). Two calibrated radiologists assessed the cone beam computed tomography images independently and blindly for AP identification and quantification. Rank‐based analysis of covariance was used for statistical analysis of lesion size. Results AP was induced in all teeth. Following RCT, all AP lesions in the 3 groups showed a significant reduction in size. Specific pairwise comparisons of the related samples (Friedmans 2‐way analysis of variance by ranks within each group) demonstrated a decreasing trend in lesion size with healing time in all 3 groups, most pronounced for local group (local adalimumab). No statistical difference was noticed between groups. Conclusions Both systemic and local anti‐TNF&agr; did not hinder AP healing in this animal model and a faster healing response may also be anticipated. These findings encourage follow‐up studies with larger sample sizes. HighlightsAnti‐TNF&agr; medications are tested in an animal model (ferrets) to evaluate the response to treatment of apical periodontitis.Anti‐TNF&agr; medications do not hinder healing of apical periodontitis in this animal model.A faster healing response also may be anticipated when using these medications when adequate endodontic treatment is performed.

Fractional uptake of radioactive rubidium in oral tissues of the rat

Abstract The fractional uptake of radioactive rubidium was used as an index of the fraction of the cardiac output going to normal and inflamed oral tissues. The findings suggest no increase in per cent of cardiac output to inflamed pulp. However, an increase in blood flow in inflamed mucosa was observed.