Degradation starts at the resin-dentine bonded interfaces within a few months’ of bonding. There are two major causes of degradation of the bonded interfaces over time. The simplified dental adhesives that are routinely used in the contemporary clinical dental practice are extremely hydrophilic and are prone to water sorption, leading to hydrolytic degradation. Dentine matrix-bound metalloproteinases (MMPs) and cysteine cathepsins (CCs) are proteolytic enzymes that have been shown to degrade the uninfiltrated demineralized collagen at the bottom of the hybrid layer. Ethanol-wet bonding (EWB) with hydrophobic adhesive has been proven to improve the longevity of resin-dentine bonds in vitro. Chlorhexidine (CHX) treatment of demineralized dentine before bonding with adhesive resin has been shown to preserve resin-dentine bond durability in vivo and in vitro by inhibition of dentine matrixbound MMPs and CCs. However, it is not known whether simultaneous application of CHX and EWB would have any interactional effect on stability of resin-dentine bonds. 1-Ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC), both a dentine collagen cross-linker and a MMP inhibitor, has been shown to preserve dentine bond durability in vitro. However, both EDC and CHX are prepared in aqueous solutions using water as a solvent for application. The MMPs are hydrolases and the presence of residual water in the demineralized dentine following EDC and CHX applications will enhance dentine bond degradation. The general aims of this thesis were to investigate the effects of solvents in resindentine bonding, in particular the role of solvents in the enhancement of resin-dentine bond durability. In the earlier part of this thesis, the adjunctive application of 2% CHX with EWB using the simplified dehydration protocol for 60 s was examined as a bonding strategy to preserve dentine bond durability to sound and caries-affected dentine. The adjunctive application of EWB and CHX preserved bond durability of hydrophobic adhesive to both sound and caries-affected dentine after 12 months’ ageing. The same bonding strategy was applied to preserve the bond durability of luting fibre post to radicular dentine. However, the addition of 2% CHX to EWB did not further improve bond durability of hydrophobic adhesive to radicular dentine, when compared to EWB alone. In the later part of this thesis, the role of the solvents (commonly used in commercial dentine adhesives) in the enhancement of dentine bond preservation potential by CHX and EDC were assessed. The incorporation of 2% CHX in ethanol showed greater inhibitory effect on matrix-bound proteases than 2% CHX in water. Conversely, the use of acetone as a solvent for EDC also enhanced its dentine collagen cross-linking potential. The dentine collagen cross-linked by EDC in acetone was more resistant to enzymatic degradation. Within the limitations of this thesis, it could be concluded that solvents play a significant role in the enhancement of dentine bond durability. In general, ethanol and acetone are better than water for the preservation of dentine bond durability. / published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

Thesis (M.S.)--University of Michigan, 1963.

Thesis (M.S.)--University of Michigan, 2005. / Includes bibliographical references.

Habilitationsschrift--Münster. / Bibliography: p. [120]-127.

Thesis (M.S.)--University of Michigan, 1963.

Thesis (M.D.S.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 87-98)

Habilitationsschrift--Münster. / Bibliography: p. [120]-127.

Regensburg, Univ., Diss., 2010 (Nicht für den Austausch)

Orientadora: Denise Pedrini / Coorientador: Alberto Carlos Botazzo Delbem / Banca: Douglas Roberto Monteiro / Banca: Carla Oliveira Favretto / Resumo: O objetivo deste estudo foi avaliar in vitro a energia livre de superfície (γS) da dentina após tratamento com trimetafosfato de sódio (TMP) associado ou não ao fluoreto (F), exposto ou não ao cálcio (Ca), bem como, a adsorção de TMP, F e Ca na dentina. Blocos de dentina bovino (4 mm x 4 mm, n=12 blocos/grupo) foram tratados por meio da imersão em soluções contendo TMP nas concentrações: 0%; 1%; 3% e 9% seguido da aplicação ou não de Ca. Estas concentrações de TMP foram associadas ou não ao F na concentração de 1100 ppm F. Foram determinadas as concentrações de F, Ca e TMP nas soluções antes e após o tratamento para calcular a adsorção destes a dentina. Para analisar a energia livre de superfície (γS) da dentina, os componentes apolar (γSLW) e polar (γSAB) eram determinados após os tratamentos por meio da medida do ângulo de contato. Os dados foram submetidos à análise de variância a dois critérios seguidos pelo teste Student-Newman-Keuls (p<0,05). O TMP reduziu a γS da dentina e aumentou os sítios doadores de elétrons (γS). Houve correlação positiva entre a adsorção de TMP e os valores de γS (Pearson's r=0,801; p<0,001). Maiores valores de γS levou a maior adsorção de Ca (p<0,001). A associação F/TMP não alterou a γS e γSLW e reduziu os valores de γS, entretanto houve maior adsorção de Ca. Houve correlação positiva entre a adsorção de TMP e F (Pearson's r=0,871; p<0,001). Concluiu-se que o TMP aumentou a γS e adsorção de Ca, e reduziu a γS. A associação com o F aumentou... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The objective of this study was to evaluate in vitro the free surface energy (γS) of dentin after treatment with sodium trimetaphosphate (TMP) associated or not to fluoride (F), exposed or not to calcium (Ca), as well as the adsorption of TMP, F and Ca in dentin. Bovine dentin blocks (4 mm x 4 mm, n=12 blocks/group) were treated by immersion in solutions containing TMP at concentrations: 0%; 1%; 3% and 9% followed or not by the application of Ca. These concentrations of TMP were or not associated with F at the concentration of 1100 ppm F. Concentrations of F, Ca and TMP were determined in the solutions before and after the treatment to calculate the adsorption to the dentin. To analyze the free surface energy (γS) of the dentin, the apolar (γSLW) and polar (γSAB) components were determined after the treatments by means of the contact angle measurement. Data were submitted to analysis of variance at two criteria followed by the Student-Newman-Keuls test (p<0.05). The results showed that TMP reduces γS of dentin and increases electron donor sites (γS). There was a positive correlation between the adsorption of TMP and the values of γS, (Pearson's r=0.801; p<0.001). Higher values of γS led to higher adsorption of Ca (p<0.001). The F/TMP association did not change γS and γSLW and reduced the values of γS,, but the adsorption of calcium was higher. There was a positive correlation between the adsorption of TMP and F (Pearson's r=0.871, p<0.001). TMP increased γS and Ca adsorp... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-10-09T12:50:16Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:02Z (GMT). No. of bitstreams: 1 10827.pdf: 7513346 bytes, checksum: c9f7e38c15b5625e4417859ce83b1118 (MD5) / Dissertacao (Mestrado Profissionalizante em Lasers em Odontologia) / IPEN/D-MPLO / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP; Faculdade de Odontologia, Universidade de Sao Paulo