title: Evaluation of ultrasonically placed MTA and fracture resistance with intracanal composite resin in a model of apexification.
abstract: The purpose of this study was to evaluate whether intracoronal delivery of an apical barrier of mineral trioxide aggregate (MTA) placed ultrasonically, non-ultrasonically, or ultrasonically with the addition of an intracanal composite resin provided a better seal against bacterial leakage. A second purpose was to determine whether intracanal composite resin or gutta-percha and sealer placed against an apical barrier of MTA provided greater resistance to root fracture. In a standardized in vitro open apex model, MTA was placed as an apical barrier at a thickness of 4 mm, with and without ultrasonic vibration. The barriers were challenged with bacteria exposure within a leakage model, and fracture resistance was assessed with increasing forces applied via an Instron machine. After 45 days, the addition of ultrasonics significantly improved the MTA seal, compared with the non-ultrasonics treatment (Kruskal Wallis nonparametric ANOVA with Dunn multiple comparison test p < 0.05). Bacterial leakage occurred in 6 (33%) of 18 in the non-ultrasonic MTA group, 2 (11%) of 18 in the ultrasonic MTA group, and 1 (6%) of 18 in the ultrasonic MTA-composite group. There were no significant differences at 90 days. A 4-mm thickness of MTA followed with an intracanal composite resin demonstrated a significantly greater resistance to root fracture than MTA followed with gutta-percha and sealer (one-way ANOVA with Newman-Keuls multiple comparison test, p < 0.01). The MTA-gutta-percha group was not significantly different than the MTA unrestored positive control.
authors.affiliation: Department of Endodontics, Wilford Hall Medical Center, Lackland AFB, Texas, USA.
authors.forename: G Robert
authors.initials: GR
authors.lastname: Lawley
authors.forename: William G
authors.initials: WG
authors.lastname: Schindler
authors.forename: William A
authors.initials: WA
authors.lastname: Walker
authors.forename: David
authors.initials: D
authors.lastname: Kolodrubetz
mesh_terms: D017607:Aluminum Compounds / Q000494:pharmacology; D000704:Analysis of Variance; D001641:Bicuspid; D017610:Calcium Compounds / Q000494:pharmacology; D003188:Composite Resins; D003763:Dental Leakage / Q000517:prevention & control; D003799:Dental Stress Analysis; D004338:Drug Combinations; D006171:Gutta-Percha; D006801:Humans; D007180:Incisor; D008422:Materials Testing; D010087:Oxides / Q000494:pharmacology; D012387:Root Canal Filling Materials / Q000494:pharmacology; D012389:Root Canal Obturation / Q000379:methods*; D017640:Silicates / Q000494:pharmacology; D019227:Tooth Apex / Q000187:drug effects* / Q000502:physiology; D014082:Tooth Fractures / Q000517:prevention & control*; D014465:Ultrasonics
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D003188:Composite Resins; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate; C078905:Bisfil; D006171:Gutta-Percha