Jeffrey W. Hutter

Comparison of the Cleaning Efficacy of Passive Sonic Activation and Passive Ultrasonic Activation After Hand Instrumentation in Molar Root Canals

The purpose of this study was to compare the cleaning efficacy of passive ultrasonic activation with that of passive sonic activation after hand instrumentation. Sixty curved molar canals were hand-instrumented to size 35 and divided into three groups. Group 1 received no further treatment. Group 2 received 3 min of passive sonic activation. Group 3 received 3 min of passive ultrasonic activation. The roots were split and photomicrographs (x20) were made of the apical 6 mm of canal. A transparent grid was placed over projected images, and the total number of squares covering the apical 6 mm of canal space and the number of squares containing debris were counted. A debris score was calculated for each specimen by dividing the number of squares with debris by the total number of squares. The mean debris scores were 31.6% for hand instrumentation only, 15.1% for the sonic group, and 16.7% for the ultrasonic group. The debris scores for the sonic and ultrasonic activation groups were significantly lower than that for the hand instrumentation only group (p < 0.01); however, there was no significant difference between the sonic and ultrasonic activation groups. Passive sonics after hand instrumentation produces a cleaner canal than hand instrumentation alone and is comparable with that of passive ultrasonics.

Clinical evaluation of bacterial leakage of endodontic temporary filling materials

This study was an in vivo comparison of the bacterial leakage associated with three endodontic temporary restorative materials: Cavit, Intermediate Restorative Material (IRM), and TERM. The access openings of 51 endodontically treated teeth were randomly sealed with a 4-mm thickness of one of the three materials. Three wk after placement of each temporary restoration, bacterial leakage was evaluated by sampling from beneath the temporary restoration and then culturing the samples both aerobically and anaerobically. Positive growth occurred in 4 of 14 TERM samples and in 1 of 18 IRM samples. Cavit did not demonstrate leakage in any of the teeth in which it was used. Cavit provided a significantly better seal than TERM over the study period.

Leakage of amalgam and super-EBA root-end fillings using two preparation techniques and surgical microscopy

An in vitro dye leakage study was conducted to test the root-end sealing ability of amalgam with varnish or Super-EBA using two root-end preparation techniques and surgical microscopy. Sixty-four single-rooted teeth were instrumented and obturated with gutta-percha. Teeth were randomly placed into four groups. Two groups received perpendicular root-end resections, 3-mm-deep ultrasonic root-end preparations, and either amalgam with varnish or Super-EBA root-end fillings. The other two groups received beveled root-end resections, 3-mm-deep micro-handpiece preparations, and either amalgam with varnish or Super-EBA. All root-end procedures were performed at x5 to x8 magnification. Micro-leakage was assessed at 4 months using methylene blue dye and a passive hydrostatic pressure technique. Statistical analysis showed that, regardless of technique, Super-EBA leaked significantly less than amalgam with varnish. There was no significant difference between the two root-end resection and preparation techniques.

Direct digital radiography versus conventional radiography for estimation of canal length in curved canals

A recent development in direct digital radiography (DDR) has made it possible to make additive multiple point (click) measurements of onscreen images. Canal length was examined using four estimation methods: measurement of a conventional D-speed film radiograph, and onscreen DDR allowing two clicks, six clicks, and an unlimited number of clicks of the measuring device. Thirty extracted human teeth with root curvatures ranging from 7 degrees to 47 degrees (Schneider method) were examined. Actual canal length was measured using a millimeter rule and x 2 magnification. Teeth were mounted and prepared for conventional and DDR imaging. Estimated canal length was determined by three board-certified endodontists using each of the four techniques. A two-way analysis of variance indicated that all radiographic techniques resulted in canal lengths that were significantly different from the true canal length, and there was no significant difference between experimental groups, regardless of the canal curvature.

An in vitro study of furcation perforation repair using calcium phosphate cement

Furcation perforations created in the pulpal floors of 30 extracted human molars were repaired with either light-cured glass ionomer cement (GI), calcium phosphate cement (CPC), or light-cured glass ionomer cement placed over a CPC matrix (M). After the cement was set, the teeth were immersed in India Ink for 48 h, dried, and sectioned longitudinally. Dye penetration into the furcation repair was independently evaluated by three board-certified endodontists. There was no significant difference in the mean extent of dye leakage among the three experimental groups. The use of CPC, with its enhanced biocompatibility, potential for osteoconduction, and sealing ability, may improve the prognosis of teeth with furcation perforations.

An in vitro evaluation of microleakage of a new root canal sealer

An in vitro dye leakage study was performed to compare the apical microleakage of Ketac-Endo root canal sealer with that of Roths 801E and AH26 sealers. Sixty-four single-rooted human teeth were instrumented and randomly divided into four groups. Three groups were obturated with laterally condensed gutta-percha and either Roths 801E, AH26, or Ketac-Endo as the sealer. A fourth group was obturated using a single master cone and the Ketac-Endo sealer. The teeth were suspended in 1% methylene blue dye for 6 days. The teeth were then longitudinally sectioned and evaluated for linear apical dye penetration. In general, Ketac-Endo root canal sealer showed greater dye penetration than Roths 801E and AH26. There was no statistical difference in leakage between the laterally condensed Ketac-Endo group and the single-cone-obturated Ketac-Endo group.

Use of an electronic apex locator on a cardiac pacemaker patient

Modern cardiac pacemakers are complex and heterogenous devices. The potential effect of electrically powered instruments on a patients pacemaker function must be carefully evaluated before treatment. Interference with the pacemakers function by the instrument depends on the specific type of pacemaker placed and the patients dependence on it. A case is presented in which an electronic apex locator was used on a patient with a pacemaker, despite the manufacturers written warning to the contrary. The patients cardiologist was consulted before treatment.

Production of interleukin-1 by polymorphonuclear leukocytes resident in periradicular tissue

Twenty-one patients undergoing endodontic surgery were identified. Periradicular tissue samples were recovered, and those showing significant numbers of polymorphonuclear leukocyte (PMN) infiltration were prepared for immunoperoxidase identification of interleukin (IL)-1 alpha and IL-1 beta-producing cells using specific polyclonal antibodies. In selected tissue specimens, 90% or more of the PMNs were found to stain positively for IL-1 alpha and IL-1 beta. In addition, significant numbers of plasma cells and tissue histiocytes stained positively for these ILs. Cell suspensions from selected periapical granuloma specimens, as well as from purified peripheral blood PMNs and peripheral blood mononuclear cells, were also subjected to IL-1 quantitation using a commercial ELISA procedure. Such cell suspensions were found to produce significant levels of IL and could be stimulated to produce increased levels after coculture with lipopolysaccharide. These results suggest that PMNs in inflammatory periradicular tissues may be a significant source of IL-1, and their possible roles in the establishment and resolution of periradicular lesions need to be re-evaluated.

Interleukin-6 in neutrophils from peripheral blood and inflammatory periradicular tissues

Periradicular tissue samples were recovered from patients undergoing endodontic surgery. Immunohistochemical procedures were used to identify interleukin-6 (IL-6) present in the neutrophils associated with these lesions. Using specific polyclonal antibody, 15 to 20% of the neutrophils associated with the periradicular tissue lesions were positive for IL-6. IL-6-positive plasma cells and histiocytes were also abundant. Cytokine production by neutrophils from the peripheral blood of nondiseased individuals was also evaluated. The cells were stimulated with lipopolysaccharides and bacterial extracts of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. Significant levels of IL-6 were produced by cells stimulated with Escherichia coli lipopolysaccharide B5 (933 pg/ml/10(7) neutrophils) and E. coli lipopolysaccharide B12 (791 pg/ml/10(7) neutrophils) when compared with unstimulated cells (39.31 pg/ml/10(7) cells). There was a dose-dependent increase in IL-6 production when cells were stimulated for 24 h with 6 and 12 micrograms/ml of A. actinomycetemcomitans extract. Less stimulation occurred with P. gingivalis, but it was also dose-dependent. Neutrophils resident in periradicular lesions may, therefore, provide a source of IL-6 in addition to that produced by tissue histiocytes and plasma cells.

Linear Dye Penetration of a Calcium Phosphate Cement Apical Barrier

Linear dye penetration was evaluated in teeth with open apices in which calcium phosphate cement was used as an apical barrier to facilitate obturation. The apical foramens of 42 extracted single-rooted human teeth were opened to a size 90 file. Half the teeth received apical barriers consisting of calcium phosphate cement (CPC) followed by obturation using a customized gutta-percha cone/ lateral condensation technique. The other half were obturated without benefit of apical barriers. Linear dye penetration was measured after 48 h exposure to India ink. The teeth receiving apical CPC barriers before obturation had significantly less dye penetration than teeth without apical barriers. Based on its proven biocompatibility and osteconductive potential, calcium phosphate cement may serve well as a replacement for calcium hydroxide in a single-visit immediate apical barrier apexification technique.