Billie G. Jeansonne

Coronal leakage: Effects of smear layer, obturation technique, and sealer

Coronal microleakage may be a major factor in the etiology of treatment failure. This study examined the effect of obturation technique, sealer, and the presence of smear layer on coronal microleakage. Two hundred extracted human teeth were assigned to 20 treatment groups. Groups were examined with the smear layer present or smear layer removed (17% REDTA). Access cavities were exposed to artificial saliva then Pelikan Ink. Teeth were cleared and linear dye penetration measured. When all groups with the smear layer removed were compared with all groups with the smear layer present, significantly less leakage was seen when the smear layer was removed. Ultrafil displayed significantly more leakage than all other groups. Vertical compaction of lateral condensation and Thermafil obturations significantly reduced leakage. AH-26 displayed significantly less leakage than Roths 811 sealer. These results indicate that removal of the smear layer, the use of AH-26, and vertical compactin have cumulative effects in reducing coronal leakage.

In vitro evaluation of a carbon fiber post

The purpose of this study was to evaluate the influence of endodontic and restorative procedures on fracture resistance of teeth, and to compare the incidence of root fracture in teeth with clinical crowns removed that were restored with three different types of post and a composite core build-up. Seven groups of 10 extracted maxillary canines were used. A control group had only a crown preparation, but no endodontic treatment. Three groups had endodontic treatment, crown preparation, and the access restored. Three groups had endodontic treatment, the crown totally removed, a tapered, parallel, or carbon post placed, and a composite build-up. All specimens were subjected to a 45-degree load at 0.5 mm/min until failure occurred. The force at failure and the location of fracture were recorded. The groups with post and composite build-ups failed at significantly lower force than the teeth in which the crowns had not been removed. There were no significant differences in the amount of force required to produce failure among the three groups with different posts and a composite build-up. The group restored with the carbon post had no root fractures, whereas there were five fractures in each of the parallel and tapered post groups.

Effect of an Acid Environment on Leakage of Root-End Filling Materials

One hundred fifty-six single-rooted human extracted teeth received root canal treatment, apicoectomy, and ultrasonic root-end preparations. The roots were divided into six groups of 24 teeth. The groups were filled with Amalgam, Geristore, Super-EBA, Mineral Trioxide Aggregate (MTA), Calcium Phosphate Cement (CPC), or MTA with CPC matrix, respectively. Immediately after root-end filling, 12 teeth from each group were exposed to a pH of 5.0 for 24 h, and 12 teeth were exposed to a pH of 7.4 for 24 h. Twelve teeth served as controls. All teeth were exposed to Pelikan Ink for 5 days and cleared. Linear dye leakage was recorded. Data were statistically analyzed. An acid pH significantly reduced dye leakage of Geristore (0.67 vs. 3.93 mm) and MTA with CPC matrix (0.54 vs. 2.41 mm), whereas leakage of all other materials was not affected by pH. In conclusion an acid environment did not hinder the sealing ability of any of the materials tested, and enhanced the sealing ability of Geristore and MTA with CPC matrix.

Ferric sulfate hemostasis: Effect on osseous wound healing. I. Left in situ for maximum exposure*

Ferric sulfate solution is an accepted soft tissue hemostatic agent for use in dermatology and dentistry. This study was designed to test its effect on osseous healing when used during surgery to control osseous hemorrhage. Standardized osseous defects were created bilaterally in the naturally edentulous zone in rabbit mandibles. The control site was sutured immediately after clot formation in the defect. The contralateral experimental site received ferric sulfate application until complete hemostasis was achieved. The defect was filled with ferric sulfate solution to maximize any effect on healing and then closed with sutures. The experimental and control specimens were examined histologically after 18 and 46 days and scored for healing. Statistical analysis by Wilcoxon signed rank test showed significant adverse effects on osseous healing when ferric sulfate solution was left in situ.

Adhesion of human fibroblasts to root-end-filling materials.

This study evaluated the attachment of cultured explants of human periodontal ligament fibroblasts and gingival fibroblasts to different root-end-filling materials. Although periodontal ligament and gingival fibroblasts initially attached avidly to Geristore, these same cells displayed no significant attachment to ProRoot, Tytin amalgam, or SuperEBA. With further incubation on Geristore, the attachment of both periodontal ligament and gingival fibroblasts improved and these cells proliferated. In contrast, no improvement in attachment or proliferation was observed for cells incubated for greater times with ProRoot, Tytin amalgam, or SuperEBA. Because the attachment characteristics of these two groups of fibroblasts were identical, we examined the potential role of the extracellular matrix family of receptors (integrins) on the attachment of gingival fibroblasts. Gingival fibroblast attachment to collagen type I was determined to be dependent on alpha1beta1 and alpha2beta1 integrins, whereas their attachment to the RGD-binding sequence of fibronectin and vitronectin was partially inhibited by antibodies to the beta1 and alphaV integrin subunits. However, attachment of gingival fibroblasts to Geristore was not reduced by the addition of any of the attachment-perturbing anti-integrin antibodies examined. Thus, gingival fibroblasts attach to Geristore, but this attachment was mediated by mechanisms other than integrins.

Comparison of calcium hydroxide and zinc oxide and eugenol pulpectomies in primary teeth of dogs.

The purpose of this investigation was to compare calcium hydroxide with zinc oxide and eugenol (ZOE) as root canal obturants in the pulpectomy procedure for irreversibly inflamed primary pulps of dogs. Clinical, radiographic, and histologic comparisons of calcium hydroxide and ZOE root canal filling materials were made in forty-two primary premolars of seven mongrel puppies. When the animals were 6 weeks of age, the pulps of all samples teeth were extirpated and the canals left open to the oral environment. The root canals were assigned to calcium hydroxide, ZOE, and control groups, instrumented, and filled 2 weeks later. The animals were killed 1 day, 1 week, 4 weeks, and 12 weeks after filling. Statistical analysis of all categories for comparison at 4 weeks indicated that calcium hydroxide gave significantly more favorable results than ZOE. Canals treated with calcium hydroxide exhibited less inflammation, less resorption, and more hard-tissue apposition than ZOE-treated and control groups.

Ferric Sulfate Hemostasis: Effect on Osseous Wound Healing, II, With Curettage and Irrigation

Hemorrhage control is often a problem for the clinician during osseous surgery. Ferric sulfate is an effective hemostatic agent, but with prolonged application to an osseous defect can cause persistent inflammation and delayed healing. The purpose of this investigation was to evaluate the effectiveness of ferric sulfate as a hemostatic agent and to determine its effect on healing after thorough curettage and irrigation from osseous surgical wounds. Standard size osseous defects were created bilaterally in the mandibles of rabbits. Ferric sulfate was placed in one defect until hemostasis was obtained; the contralateral defect was allowed to fill with blood and clot. After 5 min both defects were curetted and irrigated. The repair of the defects was evaluated histologically at 18 and 46 days. There were no significant differences between the ferric sulfate-treated defects and the untreated controls. When adequately curetted and irrigated from the surgical site prior to closure, ferric sulfate did not cause persistent inflammation or delay osseous repair in comparison to controls.

Multiple autoclave cycle effects on cyclic fatigue of nickel-titanium rotary files produced by new manufacturing methods

INTRODUCTION Novel nickel-titanium rotary files with proprietary manufacturing techniques have recently been marketed. The purpose of this study was to assess multiple autoclave cycle effects on cyclic fatigue of GT Series X files (Dentsply Tulsa Dental Specialties, Tulsa, OK) and Twisted Files (SybronEndo, Orange, CA) METHODS: A jig using a 5-mm radius curve with 90° of maximum file flexure was used to induce cyclic fatigue failure. Files (n = 10) representing each experimental group (GT Series X 20/.04 and 20/.06; Twisted Files 25/.04 and 25/.06) were first tested to establish baseline mean cycles to failure (MCF). Experimental groups (n = 20) were then cycled to 25% of the established baseline MCF and then autoclaved. Additional autoclaving was accomplished at 50% and 75% of MCF followed by continual testing until failure. Control groups (n = 20) underwent the same procedures except autoclaving was not accomplished. RESULTS The GT Series X (20/.04 and 20/.06) files showed no significant difference (p = 0.918/p = 0.096) in MCF for experimental versus control files. Twisted Files (25/.04) showed no significant difference (p = 0.432) in MCF between experimental and control groups. However, the Twisted Files (25/.06) experimental group showed a significantly lower (p = 0.0175) MCF compared with the controls. CONCLUSIONS Under the conditions of this evaluation, autoclave sterilization significantly decreased cyclic fatigue resistance of one of the four file groups tested. Repeated autoclaving significantly reduced the MCF of 25/.06 Twisted Files; however, 25/.04 Twisted Files and both GT Series X files tested were not significantly affected by the same conditions.

The effect of guided tissue regeneration on the healing of osseous defects in rat calvaria.

The effect of guided tissue regeneration procedures on the healing of osseous defects was studied in Sprague-Dawley rats. A full thickness flap was reflected and two 5 mm defects were made in the calvaria of 17 rats. A resorbable membrane was placed over one defect in each animal, while the remaining defect served as a control. After 3, 5, or 7 wk, healing of the osseous defects was evaluated histologically. There was no statistical difference in bone regeneration between experimental and control sites at any time period.

The effect of irrigation with doxycycline or citric acid on leakage and osseous wound healing.

This study investigated the effect of doxycycline irrigation on wound healing and the apical seal of three filling materials. Part 1: 220 extracted teeth received root canal therapy followed by root resection (2 mm) and ultrasonic root end preparations (3 mm). Groups of 20 were irrigated with saline, citric acid, or doxycycline and filled with amalgam, Super EBA, or MTA. Leakage was measured (mm) after decalcification and clearing. Part 2: two defects were made on each side of the mandible of 10 New Zealand rabbits. On each side, one defect was irrigated with saline and one with either citric acid or doxycycline. The animals were killed in groups of five at 9 and 18 days. Sections of each defect were stained with hematoxylin and eosin for evaluation of healing and bone fill. Super EBA and MTA leaked significantly less than amalgam, regardless of irrigant. Leakage after irrigation with doxycycline compared to citric acid or saline was not significantly different for Super EBA or MTA but was lower for amalgam. There was no significant difference in healing or bone fill among irrigants at 9 or 18 days.