published_or_final_version / Paediatric Dentistry / Master / Master of Dental Surgery

Ethanol‐wet bonding (EW) has been proved to effectively infiltrate hydrophobic monomers into the demineralized hydrophilic dentin matrix and create a more degradation‐resistant network when bonding to normal dentin. Caries-affected dentin (CAD) has consistently demonstrated lower bond strength than normal dentin. Objective: To evaluate effect of EW on resin-CAD bond strength. Methods: Seventy five human molars with occlusal caries were randomly divided into water-wet (WW) and EW groups. CAD was obtained using the combined criteria of visual examination, surface hardness to an excavator and carbide bur and staining with 1% acid red in propylene glycol dye solution (Caries detector, Kuraray). For EW, the etched and water rinsed dentin was subsequently rinsed with absolute ethanol for 15s x3 before primer application. Four bonding agents, Bis-GMA/TEGDMA (ER2), Bis-GMA/HEMA (ER3), Bis-GMA/2-MP/HEMA (ER5), and Adper Scotchbond Multi Purpose (SBMP) were applied followed by resin-based composite (Heliomolar, Ivoclar Vivadent) incrementally built-up. Specimens (549) with a square cross-sectional area of approximately 0.7 mm2 were formed. Specimens (one day: 263; 6 month: 276) were subjected to micro-tensile bond test. Data were analyzed by one two-way and three-way ANOVA, two-sample t-test, and the parametric Weibull regression models. Result: There was a significant difference in the mean microtensile bond strength between WW and EW substrate condition for ER2 (p=0.0443). The mean microtensile bond strength with EW was significantly greater. Conclusion: Unlike prior research using normal dentin, EW bonding had significant effect only on 6 month bond strength to CAD for ER2.

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Advances in the field of medicine have extended the average human life expectancy worldwide. As a result an increasing number of people will suffer from problems associated with their mineralized tissues and will require orthopedic and dental implants to restore their quality of life. Ideally, implants should have mechanical and structural properties compatible with the original mineralized tissue, and should also promote faster and stronger implant fixation. An improved understanding of the properties of mineralized tissues can help with the improvements of implants. This thesis focuses on improving the understanding of two aspects related to mineralized tissues and implant systems: the mechanical properties of peri-implant bone, and the mechanical, composition and structural properties of dentin and jawbone. Studies have shown that local delivery of alendronate, an anti-osteoporosis drug, enhances new bone formation; however, the effects of the drug on the elastic modulus of new formed bone are unknown. In this study, nanoindentation was used to evaluate and compare the elastic modulus of peri-implant bone with and without the presence of alendronate. To better understand the properties of dentin and jawbone, nanoindentation and qualitative backscattered electron imaging were used to measure their elastic modulus, mineral content and volume fraction, and regression analyses were used to establish correlation between the properties. In this thesis, mineralized tissue samples were collected from an animal study. To study the effects of alendronate on the elastic modulus of peri-implant bone, porous tantalum implants with three different coating treatments were used: non-coated (Ta), calcium phosphate coated (Ta-CaP), alendronate-immobilized-calcium-phosphate coated (Ta-CaP-ALN). The calcium phosphate coatings, with or without alendronate, increased the elastic modulus of peri-implant Ingrown Bone by approximately 22% (3GPa). The addition of alendronate did not significantly increase the elastic modulus of peri-implant. For the study of dentin and jawbone, regression analyses showed that the elastic modulus of dentin is strongly dependent on the porosity and to a lesser extent on the calcium content. The elastic modulus of jawbone and dentin were compared and the elasticmodulus of jawbone was generally higher than that of dentin while the mineral content was lower.

Advances in the field of medicine have extended the average human life expectancy worldwide. As a result an increasing number of people will suffer from problems associated with their mineralized tissues and will require orthopedic and dental implants to restore their quality of life. Ideally, implants should have mechanical and structural properties compatible with the original mineralized tissue, and should also promote faster and stronger implant fixation. An improved understanding of the properties of mineralized tissues can help with the improvements of implants. This thesis focuses on improving the understanding of two aspects related to mineralized tissues and implant systems: the mechanical properties of peri-implant bone, and the mechanical, composition and structural properties of dentin and jawbone. Studies have shown that local delivery of alendronate, an anti-osteoporosis drug, enhances new bone formation; however, the effects of the drug on the elastic modulus of new formed bone are unknown. In this study, nanoindentation was used to evaluate and compare the elastic modulus of peri-implant bone with and without the presence of alendronate. To better understand the properties of dentin and jawbone, nanoindentation and qualitative backscattered electron imaging were used to measure their elastic modulus, mineral content and volume fraction, and regression analyses were used to establish correlation between the properties. In this thesis, mineralized tissue samples were collected from an animal study. To study the effects of alendronate on the elastic modulus of peri-implant bone, porous tantalum implants with three different coating treatments were used: non-coated (Ta), calcium phosphate coated (Ta-CaP), alendronate-immobilized-calcium-phosphate coated (Ta-CaP-ALN). The calcium phosphate coatings, with or without alendronate, increased the elastic modulus of peri-implant Ingrown Bone by approximately 22% (3GPa). The addition of alendronate did not significantly increase the elastic modulus of peri-implant. For the study of dentin and jawbone, regression analyses showed that the elastic modulus of dentin is strongly dependent on the porosity and to a lesser extent on the calcium content. The elastic modulus of jawbone and dentin were compared and the elasticmodulus of jawbone was generally higher than that of dentin while the mineral content was lower.

Thesis (M.D.S.)--University of Hong Kong, 2008. / Also available in print.

Thesis (Ph. D.)--University of Missouri-Columbia, 1995. / Typescript. Vita. Includes bibliographical references (leaves 108-117). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1995. / Typescript. Vita. Includes bibliographical references (leaves 108-117). Also available on the Internet.

Thesis (M.D.S.)--University of Hong Kong, 2008. / Includes bibliographical references (p. 63-70).

Orientador: Edson Alves de Campos / Resumo: O objetivo deste trabalho foi avaliar a resistência de união imediata, de sistemas adesivos autocondicionantes, frente a diferentes tratamentos da superfície dentinária hipermineralizada artificialmente. Incisivos bovinos hígidos (N=80) foram preparados, incluídos em resina acrílica, hipermineralizados artificialmente e aleatoriamente distribuídos em dois grupos, de acordo com o sistema adesivo autocondicionante utilizado: Universal (3M ESPE; n=40); Optibond All in One (Kerr; n=40). Para cada sistema adesivo foram realizados cinco diferentes protocolos: (T1) sistema adesivo segundo recomendações do fabricante (n=8); (T2) ácido fosfórico 37% por 15" + sistema adesivo (n=8); (T3) laser Er,Cr:YSGG (Waterlaser Millenium, Biolaser Technology, San Clement, CA, USA) + sistema adesivo (n=8); (T4) ácido fosfórico 37% por 15" + laser Er,Cr:Y5GG + sistema adesivo (n=8); (T5) laser Er,Cr:YSGG + ácido fosfórico 37% por 15" + sistema adesivo (n=8). Após os procedimentos adesivos e restauradores, os dentes permaneceram em ambiente úmido, a 37ºC, por 24 horas, para posteriormente passarem pelo ensaio de microcisalhamento. Os resultados de resistência de união foram obtidos em MPa e submetidos à Análise de Variância e Teste de Tukey ao nível de significância de 5%. O padrão de fratura de cada espécime foi avaliado e observou-se um padrão de fratura predominantemente adesivo. Os resultados mostraram que, para o sistema adesivo Optibond All in One, o maior valor de resistência de união foi obt... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aims to evaluate the immediate bond strength of self-etching adhesive systems after different treatments of the artificially hypermineralized dentin. Bovine healthy incisors (n=80) were prepared, embedded in acrylic resin and randomly distributed into two groups according to the time of adhesive systems used: Group A - Universal (3M ESPE, n=40) and Group B - Optibond All in One (Kerr, n=40). For each adhesive system, five different protocols were performed: (T1) adhesive system according to the recommendations of the manufacturer (n=8); (T2) phosphoric acid conditioning 37 % for 15" + adhesive system (n=8); (T3) laser Er,Cr:YSGG (Waterlaser Millenium, Biolaser Technology, San Clemente, CA, USA) + adhesive system (n=8); (4) phosphoric acid conditioning 37% for 15" + laser Er,Cr:Y5GG + adhesive system (n=8); (T5) laser Er,Cr:YSGG + phosphoric acid conditioning 37% for 15" + adhesive system (n=8). After the bonding procedures and composite insertion, the specimens were maintained in a humid environment at 37ºC for 24 hours, and then submitted to the microshear bond strength test. The bond strength results were obtained in MPa and submitted to Variance Analysis and Tukey's Test at a significance level of 5%. The fracture pattern of each specimen was evaluated. The pattern fracture of each specimen was evaluated and a predominantly adhesive pattern was observed. The results showed that, for the Optibond All in One adhesive system, the highest union resistance value was ... (Complete abstract click electronic access below) / Mestre