Research Outputs (Oral Health Sciences)
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Item How to set about a research project(1986) Cleaton-Jones, P.Item Writing a research report, dissertation or thesis(1986) Cleaton-Jones, P.Item Seal development and composition at amalgam-ceramic interfaces after NaCl and Na2S storage(1987) Jodaikin, A.; Grossman, E. S.; Witcomb, M. J.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 Analyses of marginal seals in aged amalgam restorations using extraction replicas(1984) Grossman, E. S.; Witcomb, M. J.; Jodaikin, ASince dental amalgam does not bond chemically to tooth structure, a microcrevice is present at the amalgam/tooth interface of a freshly placed restoration. This gap is of sufficient width to allow fluids and microorganisms to pass along the cavity walls and thereby facilitating the recurrence of dental caries, which accounts for the majority of amalgam restoration replacements.Item Seal development and composition at amalgam-ceramic interfaces after NaC1 and Na2S storage(1987) Jodaikin, A; Grossman, ES; Witcomb, MJChlorine and sulphur -.have been found in the marginal seal of some tooth-amalgam interfaces . Although the role of Cl in the sealing process is relatively well established the role of S remains more obscure. The purpose of the present study was to compare the sealing properties and elemental composition of the seal formed at the interface of amalgams placed in ceramic cavities and stored in either a 10% NaCl or 10% Na2S aqueous solution. This investigation undertaken in a simple controlled environment, devoid of complex oral influences, would clarify the role that these two elements play in the sealing process at amalgam-tooth interfaces within the mouth.Item The effect of enamel etchants and a cleaning agent on cut dentine: an in vitro study(1985) Sparrius, O.; Grossman, E. S.Cavities 1,25 x 2,00mm were prepared in the cervical dentine of extracted human premolar teeth using a no. 577 tungsten carbide bur. The cavity depth was standardised at 1mm with the aid of a depth gauge fitted to the high speed airturbine. The cavities were hemisected with a low speed, water cooled, diamond disc saw, then cleaned with water and air. Thereafter the following solutions were applied to six cavities each as per manufacturers' instructions: Anhydron; Chemfill (Citric Acid); Enamelbond etchant and Scotchbond etchant gel. Once the cavities had been cleaned and dried, the specimens were prepared for scanning electron microscopy (SEM) and viewed at magnifications of x35, x200 and x2000. Cavity walls and floors were viewed separately and representative areas photographed. Similarly prepared unetched cavities served as a control.Item Primary fixation of vervet monkey oral epithelium for SEM and TEM(1987) Grossman, E. S.Vervet monkey attached gingiva and alveolar mucosa was used to investigate the effect of primary fixative composition and osmolarity on the scanning electron microscope appearance and epithelial cell surface feature density. Primary fixation was obtained using 12 different fixatives with osmolarities varying between 320-2010mOsm followed by further standard SEM processing procedures. All primary fixatives investigated produced acceptably fixed oral epithelium for SEM study, showing all the morphologic features characteristic of either keratinized or non-keratinized oral tissue. Point counting revealed that the density of microvilli of attached gingiva epithelial cells when fixed at 2010mOsm was 72 +/- 8% of the cell surface area. This decreased to 40 +/- 5% when fixed at 320mOsm. Similarly the microplication density of the alveolar mucosa epithelial cells decreased from 70 +/- 5% at 2010mOsm to 43 +/- 7% at 320mOsm. Both these differences proved to be highly significantItem Experimental marginal leakage around dental amalgams placed in artificial cavities(1984) Jodaikin, A.; Grossman, E. S.Experimental marginal leakage of high- and low-Cu amalgam restorations placed in acrylic teeth, where the cavities were untreated or painted with denatured collagen and/or a CaP slurry, was assessed after specimens were stored in a 1% NaCl solution for ten days and for one yr. All specimens stored for ten days showed severe marginal leakage. High- and low-Cu amalgam restorations placed in untreated acrylic teeth cavities formed seals after a storage period of one yr, indicating that these materials are able to form a seal without interacting with a natural tooth cavity interface. Cavities treated with denatured collagen also formed seals in the long-term group. It was apparent that, when the CaP slurry was used, generally more leakage resulted after the year's storage period than when amalgam restorations were placed in uncoated acrylic cavity surfaces or in those painted with denatured collagen.Item Hard tissue barrier formation in pulpotomized monkey teeth capped with cyanoacrylate or calcium hydroxide for 10 and 60 minutes(1987) Cvek, M.; Granath, L.; Cleaton-Jones, P.; Et alMonkey incisor teeth were pulpotomized in groups of 10. After physiological hemostasis, the pulps of group I were covered with isobutyl cyanoacrylate, and those of groups II and III with calcium hydroxide for 10 and 60 minutes, respectively, whereafter this compound was washed away and the wound surfaces covered with Teflon. In group IV, calcium hydroxide was used as a positive control, and Teflon as a negative control in group V. The animals were killed after 12 weeks and the teeth removed in tissue blocks. The material was processed and evaluated histologically with respect to location and continuity of a hard tissue barrier, type of newly formed hard tissue, state of the pulp, and presence of stainable bacteria in the coronal cavity. Seven of nine teeth in group I showed a hard tissue barrier. The corresponding figure for group II was eight out of 10 teeth. All teeth in groups III and IV had a barrier. The incidence of a continuous barrier increased from group I through group IV, as did the incidence of its location below the level of the original wound surface. The condition of the pulp was related to the presence of bacteria and the continuity of the barrier to the presence of inflammation. There was no bridging in group V. The results support the theory that a low-grade irritation is responsible for the formation of a hard tissue barrier in exposed pulps.