title: Root-end cavity preparation using the MicroMega Sonic Retro-prep Tip. SEM analysis.
abstract: The objective of this laboratory study was to compare root-end cavities prepared with sonic Retro-prep tips in a MM1500 Sonic Air handpiece with those created by burs in a conventional handpiece. A total of 80 single-rooted extracted human teeth with mature apices and straight canals were included in the study. Four groups of 20 extracted teeth were prepared as follows: I, a 3-4 mm root-end resection perpendicular to the long axis of the root, with a size 40 sonic Retro-prep tip creating an apical cavity 3 mm into root canal system; II, a 45 degrees bevel of the root-face removing a 3-4 mm root segment and root-end preparation as per group I; III, root-end resection as per group I, with an apical cavity prepared using a size 010 inverted cone bur 3 mm down the long axis of the root; IV, resection as per group II, followed by an apical cavity preparation with a size 010 inverted cone bur 3 mm into the root canal system. The apical root portion and root-end cavities were replicated and prepared for SEM analysis at x 20 and x 80 magnification. The degree of chipping associated with the margin of the root-end cavities, as evaluated with a standard grading system, and the incidence of root-face cracks were noted. Marginal chipping of root-end cavities prepared using sonic instrumentation was significantly worse than that produced by burs (P < 0.001). Perpendicular root-end resections showed significantly better scores than bevelled root-end resections (P < 0.005). The incidence of root-face cracking was low with no significant difference between the experimental groups.
authors.affiliation: Department of Restorative Dentistry, University of Wales College of Medicine, Cardiff, UK.
authors.forename: A
authors.initials: A
authors.lastname: Lloyd
authors.forename: A
authors.initials: A
authors.lastname: Jaunberzins
authors.forename: P M
authors.initials: PM
authors.lastname: Dummer
authors.forename: S
authors.initials: S
authors.lastname: Bryant
mesh_terms: D003762:Dental Instruments; D003786:Dental Pulp Cavity / Q000293:injuries / Q000648:ultrastructure*; D005069:Evaluation Studies as Topic; D006801:Humans; D008855:Microscopy, Electron, Scanning; D012184:Retrograde Obturation / Q000295:instrumentation*; D018915:Root Canal Preparation / Q000295:instrumentation*; D013010:Sonication / Q000295:instrumentation; D018709:Statistics, Nonparametric; D019227:Tooth Apex / Q000293:injuries / Q000648:ultrastructure*