Faculty of Health Sciences
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Item Marginal adaptation in composite resin restored dentine cavities Showing gross marginal leakage(1986) Grossman, E. S.; Sparrius, O.The aim of bonding composite resin restorations to the tooth is to ensure retention and also to prevent marginal leakage at the tooth restoration interface, a process which can lead to further caries. An in vitro marginal leakage study' of composite resins in combination wTEh acid' etching and dentine and enamel bonding agents highlighted the lower sealing potential of both enamel and dentine bonding agents to dentine (36%>seal) compared to enamel (79%>seal). Several studies 2-4 suggest that if the inner surface of the resin restoration appears as a well replicated negative impression of the adjacent tooth surface, bonding has been achieved. This study was undertaken to examine the appearance of the inner surface of resin restorations which showed gross marginal leakage in restored dentine cavities to determine the degree of marginal adaptation between the restoration and cavity surface.Item Bonding agents: adhesive layer thickness and retention to cavity surfaces with time(2001) Grossman, E. S.; Setzer, S.This study assessed bonding agent thickness, cover and the influence of long-term storage on bonding agent retention to enamel and dentine surfaces in cut occlusal cavities in 46 human molar teeth. Two specimens were etched and set aside. The remaining specimens were divided into two equal groups and treated with either Optibond or Scotchbond Multipurpose Plus (SMPP) up to the adhesive stage. Thereafter two specimens from each group were stored for 0, 1, 3, 7 and 14 days and 1, 2, 3, 6 and 12 months in 1% NaCl. After storage the cavity surfaces were examined in a scanning electron microscope (SEM) and scored as to bonding agent cover. One specimen from each treatment was then embedded in resin, two sections prepared midway through each cavity, polished and re-examined in the SEM to measure bonding agent thickness at 13 sites along the cavity surface. Both bonding agents showed highly variable and significant (P < 0.05) bonding agent cover and layer thickness according to cavity site, SMPP more so than Optibond. Pooling of SMPP adhesive was apparent in cavity angles. Mean film thickness was significantly different between Optibond (221 +/- 130 microns) and SMPP (118 +/- 106 microns). There was no significant difference in bonding agent thickness between long- and short-term storage.