O uso de implantes osseointegrados vem crescendo nas últimas décadas e, juntamente com eles, suas complicações. A periimplantite se apresenta como uma infecção bacteriana que afeta os tecidos moles e duros ao redor do implante, promovendo perda da osseointegração. Assim, o objetivo primário deste estudo foi analisar a efetividade da remoção de bactérias, através do software ImageJ, aderidas às superfícies de titânio por diferentes agentes químicos condicionantes, por meio de análise em microscopia eletrônica de varredura (MEV). Juntamente foi analisado a alteração da rugosidade de superfície após a utilização dos agentes. Foi realizado estudo in vitro, no qual 70 covers (protótipos de implantes) passaram por preparo das superfícies para adequação do meio à cultura bacteriana, fixação das bactérias; e em seguida, foram divididos em 7 grupos (n=10), de acordo com o tratamento: AF180 aplicação de ácido fosfórico (AF) por 180 segundos; AF90- AF por 90 segundos; EDTA180 EDTA por 180 segundos; EDTA90 EDTA por 90 segundos; AC180 ácido cítrico por 180 segundos; AC90 AC por 90 segundos; Controle RAR. A análise comparativa do grau de contaminação bacteriana observado antes e depois do tratamento entre os diferentes grupos foi realizada por meio do teste não paramétrico de Kruskal-Wallis; e as alterações da rugosidade superficial foram analisadas por meio do teste ANOVA a dois critérios, pós-teste de Dunnett. Através desta metodologia, este trabalho sugere que o tratamento de superfícies de titânio contaminadas por meio do emprego de solução em gel de EDTA a 24% por 90 e 180 segundos e ácido cítrico a 50% por 180 segundos é efetiva para remoção de A. atinomycetencomitans. Além disso, o tratamento por meio de EDTA por 90 e 180 segundos promove alteração significativa dos parâmetros de rugosidade superficial, especialmente quando comparado aos grupos controle e AF180, indicando que este tratamento pode resultar em subtração ácida adicional. / The use of dental implants has grown in recent decades and, with them, their complications. The periimplantitis is presented as a bacterial infection that affects the soft and hard tissue around the implant, promoting loss of osseointegration. Thus, the primary objective of this study was to analyze the effectiveness of removal of bacteria tby means of the ImageJ software, adhered to the titanium surfaces by different chemical conditions, through analysis in scanning electron microscopy (SEM). The change of surface roughness was also analyzed after using the chemical agents. An in vitro study in which 70 covers (implant prototypes) was prepared for the bacteria culture, fixation of the bacterias; and then they were divided into 7 groups (n = 10), according to the surface treatment: AF180- application of phosphoric acid (FA) for 180 seconds; AF90- AF for 90 seconds; EDTA180 - EDTA for 180 seconds; EDTA90 - EDTA for 90 seconds; AC180 - citric acid for 180 seconds; AC90 -AC for 90 seconds; Control - RAR. The comparative analysis of the degree of bacterial contamination was performed using Kruskal-Wallis non parametric test; and changes of surface roughness were analyzed by ANOVA two criteria, post-test Dunnett. Through this method, this work suggests that treatment of titanium contaminated surfaces by means of EDTA gel solution employing 24% for 90 and 180 seconds and citric acid 50% for 180 seconds is effective for removing A. atinomycetencomitans. Moreover, treatment using EDTA for 90 to 180 seconds promotes significant change of surface roughness parameters, especially when compared to control groups and AF180, indicating that this treatment can result in additional acidic subtraction.

"October, 2005" / Coursework / Bibliography: leaves 97-105. / xvi, 136 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Clin.Dent.)--University of Adelaide, Dental School (Endodontics), 2005

Thesis (Ph.D.)--University of Melbourne, Melbourne Dental School, Faculty of Medicine, Dentistry and Health Sciences, 2010. / Typescript. Includes bibliographical references.

O uso de implantes osseointegrados vem crescendo nas últimas décadas e, juntamente com eles, suas complicações. A periimplantite se apresenta como uma infecção bacteriana que afeta os tecidos moles e duros ao redor do implante, promovendo perda da osseointegração. Assim, o objetivo primário deste estudo foi analisar a efetividade da remoção de bactérias, através do software ImageJ, aderidas às superfícies de titânio por diferentes agentes químicos condicionantes, por meio de análise em microscopia eletrônica de varredura (MEV). Juntamente foi analisado a alteração da rugosidade de superfície após a utilização dos agentes. Foi realizado estudo in vitro, no qual 70 covers (protótipos de implantes) passaram por preparo das superfícies para adequação do meio à cultura bacteriana, fixação das bactérias; e em seguida, foram divididos em 7 grupos (n=10), de acordo com o tratamento: AF180 aplicação de ácido fosfórico (AF) por 180 segundos; AF90- AF por 90 segundos; EDTA180 EDTA por 180 segundos; EDTA90 EDTA por 90 segundos; AC180 ácido cítrico por 180 segundos; AC90 AC por 90 segundos; Controle RAR. A análise comparativa do grau de contaminação bacteriana observado antes e depois do tratamento entre os diferentes grupos foi realizada por meio do teste não paramétrico de Kruskal-Wallis; e as alterações da rugosidade superficial foram analisadas por meio do teste ANOVA a dois critérios, pós-teste de Dunnett. Através desta metodologia, este trabalho sugere que o tratamento de superfícies de titânio contaminadas por meio do emprego de solução em gel de EDTA a 24% por 90 e 180 segundos e ácido cítrico a 50% por 180 segundos é efetiva para remoção de A. atinomycetencomitans. Além disso, o tratamento por meio de EDTA por 90 e 180 segundos promove alteração significativa dos parâmetros de rugosidade superficial, especialmente quando comparado aos grupos controle e AF180, indicando que este tratamento pode resultar em subtração ácida adicional. / The use of dental implants has grown in recent decades and, with them, their complications. The periimplantitis is presented as a bacterial infection that affects the soft and hard tissue around the implant, promoting loss of osseointegration. Thus, the primary objective of this study was to analyze the effectiveness of removal of bacteria tby means of the ImageJ software, adhered to the titanium surfaces by different chemical conditions, through analysis in scanning electron microscopy (SEM). The change of surface roughness was also analyzed after using the chemical agents. An in vitro study in which 70 covers (implant prototypes) was prepared for the bacteria culture, fixation of the bacterias; and then they were divided into 7 groups (n = 10), according to the surface treatment: AF180- application of phosphoric acid (FA) for 180 seconds; AF90- AF for 90 seconds; EDTA180 - EDTA for 180 seconds; EDTA90 - EDTA for 90 seconds; AC180 - citric acid for 180 seconds; AC90 -AC for 90 seconds; Control - RAR. The comparative analysis of the degree of bacterial contamination was performed using Kruskal-Wallis non parametric test; and changes of surface roughness were analyzed by ANOVA two criteria, post-test Dunnett. Through this method, this work suggests that treatment of titanium contaminated surfaces by means of EDTA gel solution employing 24% for 90 and 180 seconds and citric acid 50% for 180 seconds is effective for removing A. atinomycetencomitans. Moreover, treatment using EDTA for 90 to 180 seconds promotes significant change of surface roughness parameters, especially when compared to control groups and AF180, indicating that this treatment can result in additional acidic subtraction.

Indiana University-Purdue University Indianapolis (IUPUI) / An investigation was conducted into the effect of acid etching of the enamel and the use of pins on the retention of direct filling resins when used for restoration of fractured incisor teeth. The retention secured by these techniques as related to the cavity design also was studied. Four different cavity preparations were used. The retention of the resin in all four was compared when there was no pretreatment of the enamel, when the enamel was etched by 50 per cent phosphoric acid, and when pins were used for retention. Retention was assessed on the basis of resistance of the restoration to displacement by a lingual force. No significant difference was observed in retention as related to cavity design in the control specimens. In all four cavity preparations, acid etching of the enamel and the use of two retentive pins increased the resistance of the restorations to displacement. (However; when only one "L" shaped retentive pin was employed in Conjunction with a flat incisal preparation the force required to accomplish displacement was no greater than for controls.) The acid etch technique when employed with a cavity preparation that extended 1.7 mm. or more onto the lingual surface of the enamel generally offered a higher resistance to lingual force than double pin retained restorations. There was no significant difference between the resistance offered by a circumferential preparation when the resin was retained by either acid etching or by two pins. In the acid etch technique the enamel surface area and its distribution are important factors in retention.

OBJECTIVES: This in-vitro study aimed to evaluate the effect of hydrofluoric acid etching and airborne particle abrasion on zirconia bond strength, using three different types of cement. To assess the impact of hydrofluoric acid etching on zirconia surface roughness and investigate the effect of hydrofluoric acid etching on zirconia's surface topography, microstructure, and crystal structure. MATERIALS AND METHODS: Crown-abutment simulation systems were constructed, using a custom-made zirconia tapered ring model and tapered titanium pin-abutments. Twelve groups were included in the study and classified according to the surface treatment and type of cement used. Each group had 10 specimens for a total of 120 test specimens. The fully sintered zirconia ring was alumina particle abrasion (APA) treated with a 50-μm alumina and/or etched with 9.5% HF acid, solution for 1 minute. The Ti pin was APA treated with 125-μm alumina. Three different types of cement were used: one RMGIC (GC FujiCem Evolve) and two resin composite types of cement (Panavia SA Universal and Panavia V5). A cementing jig was used to standardize the cementation process of the titanium pins to the zirconia rings. An Instron was used to obtain the retention load values. The failure load between the zirconia ring and the titanium pin was determined using an axial pullout test and the values were statistically analyzed for the effects of etching treatment, APA treatment, and cement type using JMP Pro 16. Zirconia-disk specimens were constructed using a custom-made disk model. Thirteen groups were included in the study and classified according to the hydrofluoric acid etching concentrations, consistencies, and timing used. Each group had 3 specimens. The total specimen size was thirty-nine specimens. Disks were polished and etched using 5% HF, 9.5% HF, and 40% HF acid etching concentrations, gel, and solution consistencies, and for 1 and 15 minutes of etching time. Disks were examined with an SEM, X-Ray diffractometer, and a profilometer for microstructure, crystallography, and surface roughness, respectively. RESULTS: HF acid-etching treatment significantly increased retention load compared to non-etched groups. There was no significant difference in retention load between APA-treated and non-APA-treated groups. Groups cemented with Panavia V5 showed a higher retention load compared to GC FujiCem Evolve and Panavia SA Universal. There was no significant difference in the surface roughness among the etched groups and the control groups. Roughening of the crystal boundaries with irregularities and pits was observed under SEM. As etching time and concentration increased the surface became rougher and more irregular. There were no obvious crystal structure differences between the etched groups and non-etched groups. CONCLUSIONS: Significantly different retention loads were found among tested groups. Hydrofluoric acid etching increases the bond strength of zirconia and titanium, using resin composite cement. Using hydrofluoric acid etching to pre-treat the zirconia surface may be an alternative approach to obtain sufficient bonding strength.

Indiana University-Purdue University Indianapolis (IUPUI) / Etching of enamel caries lesions has been demonstrated to enhance remineralization. However, this effect reaches a plateau after a period of time. This study aimed at investigating the effectiveness of additional acid etching on remineralization. Forty 1 mm × 2 mm human enamel blocks with chemically induced artificial incipient lesions were used. Ten specimens were randomly selected at the end of demineralization for transverse microradiography (TMR) analysis. The remaining specimens were then divided into three groups (n = 10). Group A was remineralized by a pH cycling system with 1100 ppm sodium fluoride for 20 days. In group B, the specimens were etched with 35-percent phosphoric acid for 30 s and then remineralized. Group C was remineralized by same procedure as group B plus and given an additional acid etch after 10 days of remineralization. Mineral density was measured by x-ray microtomography (µ-CT). The volumetric mineral content [VM (µm3×105)] was determined between 91 and 0-wt%. The µ-CT % mineral recovery (%) was calculated using the formula 100×(remineralize VM - demineralization VM) / (sound VM - demineralization VM). One-hundred-μm sections of demineralized and remineralized specimens were used to assess the mineral loss (IML: vol%×µm) and lesion depth (µm) using TMR. The three groups showed no significant difference in mineral change or mineral content for µ-CT or TMR lesion depth. The TMR IML showed a significant difference between the demineralized specimens and the three remineralized groups. The correlation between TMR IML and TMR lesion depth was 0.66 (p < 0.0001). The µ-CT percent mineral recovery from demineralization was correlated with neither TMR IML nor TMR lesion depth. When evaluated with µ-CT, the twice-acid-etched group presented lower mineral gain values than the group etched only once with acid. Also, the twice-etched group presented lower mineral gain and greater TMR IML compared with the non-acid etch group. TMR images revealed reduction of surface layer in the acid-etched groups, especially in the twice-etched group, in which significant reduction or loss of surface layer occurred. Based on these results, we conclude that additional acid etching with 35-percent phosphoric acid does not enhance remineralization compared with a single application of acid etching. We believe that the viable existence of the surface layer is essential for remineralization of the lesion. Further investigations into the accuracy of µ-CT to detect minute mineral changes in incipient caries lesions are probably needed.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O uso de primers autocondicionantes e de bráquetes com compósito pré-incorporado tem sido apresentado como uma alternativa para a redução de passos clínicos. O propósito deste estudo foi avaliar o efeito de um primer autocondicionante (Transbond Plus Self-Etching Primer - SEP) na resistência ao cisalhamento de bráquetes com compósito pré-incorporado colados in vivo. A amostra consistiu de 92 dentes obtidos de 23 pacientes com indicação prévia de extração de 4 pré-molares. Os dentes foram divididos em 4 grupos, sendo os bráquetes colados pelo mesmo operador, alternando os quadrantes em cada paciente: Grupo 1 (controle) - Ácido fosfórico à 37% + primer (Transbond XT Primer) + compósito (Transbond XT Adhesive Paste) + bráquete convencional; Grupo 2 - Ácido fosfórico à 37% + primer + bráquete com compósito pré-incorporado; Grupo 3 SEP + compósito + bráquete convencional; Grupo 4 - SEP + bráquete com compósito pré-incorporado. Após 30 dias os pré-molares foram extraídos, sendo submetidos ao teste de resistência ao cisalhamento através da uma Máquina de Ensaios Universal, com velocidade de 0,5mm/min. Os dados obtidos pelos grupos foram analisados com 2-way ANOVA (p<0,05). As forças médias e desvios padrão obtidos foram os seguintes: Grupo 1 = 11,35 (2,36) MPa; Grupo 2 = 9,77 (2,49) MPa; Grupo 3 = 10,89 (2,60) MPa; e Grupo 4 = 10,16 (2,75) MPa. Não foi observada diferença significativa entre o uso do SEP e o de condicionador e primer tradicionais (p = 0,948). De qualquer modo, diferenças significativas na força de adesão foram observadas quando utilizados bráquetes com compósito pré-incorporado (p = 0,032). Pode ser concluído que a combinação do primer autocondicionante com o bráquete com compósito pré-incorporado apresentou valores de força de adesão adequados, sendo promissora para uso clínico. / The use of self-etching primers and precoated brackets are presented as alternatives to shorten the clinical bonding steps. The aim of this study was to evaluate the influence of a self-etching primer - SEP (Transbond Plus SEP, 3M Unitek) on shear bond strength of adhesive uncoated and precoated Victory brackets (3M Unitek). The sample group consisted of 23 patients with 4 premolars each one, equally divided in four different groups according to the bracket and enamel preparation. Brackets were bonded in vivo, by the same operator, using a split mouth random technique: Group 1- 37% Phosphoric acid + primer + composite + conventional Victory bracket; Group 2- 37% Phosphoric acid + primer + precoated Victory bracket; Group 3- SEP + composite + conventional bracket; Group 4- SEP + precoated bracket. After 30 days premolars were extracted for orthodontic reasons, and a Universal Testing Machine was used to apply an occlusal shear force directly to the enamel-bracket interface at a speed of 0.5 mm/min. Mean results and standard deviation for the groups were: Group 1 = 11,35 (2,36) MPa; Group 2 = 9,77 (2,49) MPa; Group 3 = 10,89 (2,60) MPa; e Group 4 = 10,16 (2,75) MPa. The groups were compared using 2-way ANOVA. No difference was observed while a conventional etching and primer or self-etching primer was used (p = 0.948). But, it was indicated significant differences in bond strength between uncoated and precoated brackets (p = 0.032). However, it could be concluded that the self etching primer combined with adhesive precoated brackets showed adequate shear bond strength, and may be suitable for clinical use.

Thesis (M.S.D.)--Indiana University School of Dentistry, 2009. / Title from PDF t. p. (viewed Feb. 10, 2010) Advisor(s): Masatoshi Ando, Chair of the Research Committee, Carlos Gonzalez-Cabezas, Melvin Lund, Tien-Min Gabriel Chu, Michael Cochran. Curriculum vitae. Includes abstract. Includes bibliographical references (leaves 64-70).

Diss. Stockholm : Karol. inst.