AAE Abstracts of Papers
Journal of Endodontics
(Abstract #46, continued)
(Abstract #49, continued)
the media on the opposite side of the restoration were indicative of microbial leakage. Restorations showing no leakage were observed for up to 16days. Results: In all instances, the + and- controls produced the expected results. All experimental groups showed leakage. The direction of leakage, pulp space to external or external to pulp space, did not appearto be a factor. This model system appears practical for the evaluation of microbial leakage and resorafive materials in-vitro. Supported, in part, by the AAE Research and Education Foundation.
examined. Each tooth was evaluated for pulpal health, periodontal integrity, and clinical acceptability of the restoration Of the 603 teeth that were examined, 166 had undergoneroot canal therapy prior to replacement of the restoration, leaving 437 that were crowned while vital. Of these, 25 (5.7%) were in need of root canal therapy or had undergone root canal therapy after cementation of the fixed prothesis. Of the 603 restorations, 46 (7.6%) were determined to be clinically unacceptable. Forty-one had unacceptable margins; three were retainers that had come loose; one was a fractured bridge; and one was perforated on the occlusal surface. Thirty-seven open contacts with adjacent teeth were found. An analysis of the data revealed no significant difference in pulpal failure for single crown or bridge abutment, posteriorversus anterior, or male versus female. There was no correlation between pulpal failure and clinical acceptability of the prostheses. It was concluded that the procedures used at the West Virginia University School of Dentistry to create preparation and fixed prostheses are acceptable with regard to pulpal health.
ABSTRACT #47 - Human saliva coronal leakage of unsealed endodontically treated teeth. S.J. Lee*, A. Khayat, M. Torabinejad, J. Kettering Loma Linda University, Loma Linda, California Studies have shown presence of a significant amount of coronal dye and bacterial leakage following exposure of sealed root canals to artificial and natural saliva. The purpose of this study was to determine the length of time needed for bacteria present in natural saliva to contaminate the entire length of root canals obturated by lateral and vertical condensationtechniques. Forty root canals were cleaned and shaped using a step-back technique. Thirty root canals were obturated with gutta-percha and root canal sealer using either lateral(s) or vertical(s) condensation techniques. Five root canals were obturated without a root canal sealer and served as positive controls. After obturation the coronal 3 mm of five root canals were sealed with sticky wax and served as negative controls. The coronal portions of the filling materials were placed in contact with human saliva and the number of days required for bacteria present in saliva to penetrate the entire root canals were determined. No bacterial leakageoccurred in the negative control group. Complete bacterial leakageoccurred within 2 days in the positive control group. All root canals were recontaminated in less than thirty days after coronal exposure to natural saliva. No statistical significant difference was found between the two methods of obtu ration. The results of this study indicate that a lack of integrity of coronal seal can resuIt in recontamination of sealed root canals in short period of time. ABSTRACT # 48 - Coronal dye penetration of apical fillings following post space preparation. M. Monsef*, S. Ravanshad, M. Torabinejad Shiraz University, Shiraz, Iran Loma Linda University, Loma Linda, California Most leakage studies have focussed on the degree of apical leakage following post space preparation. The purpose of this study was to compare the amount of coronal dye leakage of apical root filling materials produced by lateral condensation, vertical condensation and Thermafil techniques following post space preparation. Forty canals of palatal and distal roots of molars were cleaned and shaped using a step-back technique. Thirty were obtu rated (10each) by lateral, vertical and Thermafil techniques. Five root canals were obturated without a root canal sealer and served as positive controls. Another five root canals were obturated and their coronal half was sealed with sticky wax and served as negative controls. The coronal 5-6 mm of the filling materials were exposed to india ink for 48 hours. The depth of dye penetration was measured in all groups and statistically analyzed. The apical plugs in the Thermafil group had the highest degree of coronal leakage. The ANOVA test showed a significant statistical difference between the coronal dye leakage between this group and those found in canals filled by lateral or vertical condensation techniques. The results indicate that the apical filling materials obtained by lateral or vertical condensation leak less than those obtained by Thermafil.
ABSTRACT # 50 - Site comparisons of dentin collagen cross-links in human teeth. E. Rivera*, M. Yamauchi University of Iowa, Iowa City, Iowa Collagencovalent intermolecular cross-links provide the dentin matrix with stability and tensile strength. It is unknown whethercross-linkages vary in different tooth groups as an adaptation to functional requirements. To test this, the types and content of major cross-links in dentin of human teeth were quantified and compared from three different sites: 1. incisors, 2. premolar-canines, and 3. molars. After removal of cementum and pulp, 25 extracted teeth were pulverized individually and demineralized with EDTA. Collagenwas reduced with tritiated sodium borohydride, hydrolyzed, and subjected to amino acid and cross-link analyses. Both mature and immature cross-links were quantified as moles per mole of collagen. The findings indicated 1. all teeth contained mature (pyridino/ine and L-pyridino/ine) and immature (DHLNL and HLNL) cross-links, and 2. the content of both mature and immature cross-links increased posterior/y, being/east in incisors and greatest in molars. This suggests that dentin matrix formation maybe functionally adaptive. This study was partially supported by the NIH-NIDR Grant DE08522, DE00233, DE08611. ABSTRACT # 51 - Incidence of interappointment emergency associated with endodontic therapy. C. Mor*, I. Rotstein, S. Friedman Hebrew University, Jerusalem, Israel Past studies reported a high incidence of endodontic interappointment emergency, based on a variability of criteria used for defining it. Recently a clinical definition of endodontic interappointment emergency led to reports of a lower incidence of this clinical entity when treatment was performed by qualified operators. The purpose of this study was to assess the incidence of clinically defined endodontic interappointment emergency after treatment by undergraduate students, and to examine its correlation with preoperative and operative parameters. Randomly selected 334 patient records were retrospectively surveyed for unscheduled emergency appointments following endodontic treatment by undergraduate dental students. All treatments included step-back canal preparation in multiple visits using formocresol as interappointment intracanal medicament. Emergency patient evaluation included a comprehensive examination. Emergency treatment was individually adapted for each case, including one or more of occlusal reduction, drainage, intracanal medication, analgesics and antibiotics. The incidence of endodontic interappointment emergency found in the study material was 4.2%, and unrelated to patient's sex and age, or to tooth location. It was significantly higher in non-vital than in vital teeth (c2test, p<0.005), with the highest occurrence in non-vital teeth unassociated with periapical radiolucency (9.6%). Endodontic interappointment emergency did not
ABSTRACT # 49 - A pulpal and clinical evaluation of teeth with fixed prostheses. C. Jackson*, A.E. Skidmore, R.T. Rice West Virginia University, Morgantown, West Virginia This study was conducted to evaluatethe effects of complete coverage fixed prosthetic restorations on the dental pulp. A recall letter was mailed to 1221 patients that had received a fixed bridge or single crown during the years 1984-1988. One hundred thirty patients were 198