Evaluation of in vitro microleakage of visible light cured glass ionomer cements used as liners with composites in the 'sandwich' technique

PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact [email protected] (M.Sc.D.)--Boston University. Henry M. Goldman School of Graduate Dentistry, 1990 (Pediatric Dentistry)Bibliography: leaves 61-65.In dentistry, adhesion of restorative materials to tooth substance is an important objective. Glass ionomer cements, and more recently the visible light cured kind, are shown to chemically adhere to the dentin and enamel. The glass ionomer / composite resin combination in the 'sandwich' technique is gaining ln popularity and could extend the use of both materials in clinical practice. Since not much evidence exists in the literature, concerning visible light cured glass ionomer cements, the following investigation was undertaken with the objective of evaluating their microleakage aspect utilizing the "sandwich" technique.　　　　　　　　　　　　　　　　　　　　　　 Eighty extracted human premolar teeth were chosen for an in vitro experimental dye penetration study. A cervical 'V' shaped abrasion type lesion was prepared. Three kinds of visible light cured glass ionomers namely Vitrabond, Zionomer and XR Ionomer along with a composite control were chosen as the four study groups. Each group was subdivided into two, comprising of ten teeth each, on the basis of the technique used in placing the liner. Technique A consisted of the liner meeting the apical cavosurface margin at a point and a little short of the dentino- enamel junction at the coronal end. While technique B consisted of the liner forming the external apica1 1/3 of the restoration. The overlaid composite completed the restoration to the proper contour. The specimens were thermocycled followed by immersion in the dye (basic fuchsin) for twenty four hours. They were subsquently embedded in a resin and cut longitudinally to observe and photograph evidence of seepage of the dye. The microleakage was scored on a scale of 0-5. The results indicated that the glass ionomer liners allowed leakage primarily at the dentin margins, the leakage at the enamel restoration interface being negligible and hence not significant. Vitrabond was significantly different from the other groups, which were not signifiantly different from each other. Technique B was significantly better than technique A showing a lower mean leckage. This study thus helped in evaluating the adhesive nature of the visible light cured glass ionomer cements and in indicating which restorative technique would prove more beneficial in their conjunctional use with composite resins