The purpose of the current study was to develop a bonding method that can achieve clinically acceptable bond strength values while leaving a minimum amount of adhesive on the tooth surface during the debonding process. One hundred teeth were randomly assigned into groups. Five different enamel surface preparation protocols were tested (N = 20, each): Conventional acid etch, standard SEP, SEP applied with a light brush stroke (altered SEP 1), SEP applied directly to the composite of pre-coated bracket (altered SEP 2), and Primer Only groups. Brackets were debonded using an Instron universal testing machine (Instron, Canton, MA) in shear mode and the mean shear bond strength values were calculated. In addition, enamel surfaces were examined under light microscope to determine the location of failure using ARI. The Primer Only group had significantly lower mean shear strength (0.14 MPa, P0.05). With respect to ARI values, there was a significant difference among these four groups. 85% of samples in the altered SEP 2 group had 10% or less composite resin left on their surfaces. This group had also a mean shear bond strength value of 11.43 MPa, significantly above the minimal strength needed for orthodontic attachment bonding, and the lowest ARI values overall. Therefore, application of SEP directly to the composite resin of the pre-coated brackets may be an ideal bonding method by providing adequate bond strength and leaving a minimum amount of composite resin on the tooth surface during debonding. It should be kept in mind that future in-vivo studies would be needed to confirm the findings obtained from the current in-vitro study.

Orientador: Sizenando de Toledo Porto Neto / Banca: Marcelo Ferrarezi de Andrade / Banca: Maria Salete Machado Cândido / Banca: Alberto Magno Gonçalves / Banca: Edson Alves de Campos / Resumo: Este trabalho teve como objetivo avaliar in vitro a força de união da resina composta à dentina tratada com quatro adesivos dentinários, sendo dois sistemas universais simplificados (G1- Prime & Bond® NT/ Dentsply, G2- Single Bond/ 3M) e dois auto-condicionantes (G3- AdheSE® / Vivadent, G4- Adper- PromptL-Pop/ 3M). Para a realização deste estudo, foram selecionados 20 terceiros molares humanos íntegros e livres de cárie, que tiveram suas superfícies oclusais cortadas em 3mm. Após o corte, cada grupo de dentes receberam seus respectivos sistemas de tratamento adesivo, pré-selecionados. Todas as amostras de dentes foram restauradas com a resina composta Tetric Ceram® / IvoclarVivadent, termocicladas em 550 ciclos e cortadas. Dessa forma, obtendo-se espécimes de 1,0mm2 l0,1mm2 que foram levados a uma Máquina de Teste Universal onde foi realizado o ensaio de microtração. Os tipos de fraturas foram analisados, mediante microscopia óptica (40X) e as fraturas mais representativas foram levadas à microscopia eletrônica de varredura. Os resultados mostraram que os sistemas universais simplificados (G1 e G2) apresentaram valores de resistência de união mais elevados do que os sistemas auto-condicionantes (G3 e G4). A maioria das fraturas encontradas foram do tipo adesiva para os grupos G3 e G4, enquanto nos grupos G1 e G2 87% dos modos de fraturas foram distribuídas entre adesivas e coesivas da resina. / Abstract: This work had with aim to evaluate "in vitro" the bond strength of composite resin to dentine bonded with four dentin adhesives. In this study, were used two one-step adhesive systems (G1- Prime & Bond® NT/Dentsply, G2-Single Bond/ 3M)and two self-etching adhesive systems (G3- AdheSE® /Vivadent, G4- Adper Prompt L-Pop/3M). For this, were chosen twenty human healthy third molars, that had their oclusal surfaces cut in 3mm. After the cut, each group of teeth received their respectives adhesive systems, even then chosen. All the samples were restored with the composite Tetric Ceram® / IvoclarVivadent, thermocycled 550 times and cut. Then, obtaining specimens of 1,0mm2 l 0,1mm2 that were made a test of micro tensile bond strength in a Universal Test Machine. The fractures were analyzed in a optical microscope (40X), and the more representative fractures were then analyzed at scanning electronic microscope. The results revealed that the one-step adhesive systems (G1 and G2) showed higher values of bond strength compared to the self-etching adhesive systems (G3 and G4). The fractures more commum were the adhesive type in the G3 and G4 groups, while in the G1 and G2 groups, 87% of the fractures were the adhesive and cohesion of resin types. / Doutor

In vivo and in vitro degradation of resin-dentin interfaces can occur and accounts for poor clinical performance of adhesive dentin interfaces/restorations. Interfacial degradation results from several factors, to include, but not limited to: water sorption, hydrolysis of ester linkages of methacrylates resins, and activation of endogenous dentin matrix metalloproteinases (MMPs) in non-infiltrated collagen fibrils. Reduction of collagenolytic and gelatinolytic activity in dentin has been shown to be effective both in vivo and in vitro upon application of proteases inhibitors, such as chlorhexidine. This study compared the in vitro durability of resin-dentin bonds using microtensile testing over 12-month of water storage among five adhesive systems, including an experimental adhesive system, which had 2% chlorhexidine incorporated into the material. The results showed that all adhesive systems had a significant decrease in bond strength after 6 months, and that this reduction in bond strength was not significant different among the five adhesive systems studied. It is possible that chlorhexidine might have its inhibitory activity against MMPs lost or reduced due to chemical interaction with the adhesive system components. Also, to assess resin-dentin bonds degradation process, laboratorial studies use long-term water storage, which is labor-intense and time consuming process, therefore this study tested the possibility of accelerating the resin-dentin degradation process using water storage at 50° C. A significant reduction in microtensile bond strength occurred for specimens after 12-month storage at 50° C. The higher temperature may have increased the rate of water sorption and hydrolytic activity within the polymer network leading to adverse consequences to the interface.

Made available in DSpace on 2014-06-11T19:31:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02-28Bitstream added on 2014-06-13T20:41:46Z : No. of bitstreams: 1 xavier_ccg_dr_arafo.pdf: 2502909 bytes, checksum: 3349b0ab0c81badc5aa688fd716eaa6b (MD5) / Este trabalho teve como objetivo avaliar in vitro a força de união da resina composta à dentina tratada com quatro adesivos dentinários, sendo dois sistemas universais simplificados (G1- Prime & Bond® NT/ Dentsply, G2- Single Bond/ 3M) e dois auto-condicionantes (G3- AdheSE® / Vivadent, G4- Adper- PromptL-Pop/ 3M). Para a realização deste estudo, foram selecionados 20 terceiros molares humanos íntegros e livres de cárie, que tiveram suas superfícies oclusais cortadas em 3mm. Após o corte, cada grupo de dentes receberam seus respectivos sistemas de tratamento adesivo, pré-selecionados. Todas as amostras de dentes foram restauradas com a resina composta Tetric Ceram® / IvoclarVivadent, termocicladas em 550 ciclos e cortadas. Dessa forma, obtendo-se espécimes de 1,0mm2 l0,1mm2 que foram levados a uma Máquina de Teste Universal onde foi realizado o ensaio de microtração. Os tipos de fraturas foram analisados, mediante microscopia óptica (40X) e as fraturas mais representativas foram levadas à microscopia eletrônica de varredura. Os resultados mostraram que os sistemas universais simplificados (G1 e G2) apresentaram valores de resistência de união mais elevados do que os sistemas auto-condicionantes (G3 e G4). A maioria das fraturas encontradas foram do tipo adesiva para os grupos G3 e G4, enquanto nos grupos G1 e G2 87% dos modos de fraturas foram distribuídas entre adesivas e coesivas da resina. / This work had with aim to evaluate in vitro the bond strength of composite resin to dentine bonded with four dentin adhesives. In this study, were used two one-step adhesive systems (G1- Prime & Bond® NT/Dentsply, G2-Single Bond/ 3M)and two self-etching adhesive systems (G3- AdheSE® /Vivadent, G4- Adper Prompt L-Pop/3M). For this, were chosen twenty human healthy third molars, that had their oclusal surfaces cut in 3mm. After the cut, each group of teeth received their respectives adhesive systems, even then chosen. All the samples were restored with the composite Tetric Ceram® / IvoclarVivadent, thermocycled 550 times and cut. Then, obtaining specimens of 1,0mm2 l 0,1mm2 that were made a test of micro tensile bond strength in a Universal Test Machine. The fractures were analyzed in a optical microscope (40X), and the more representative fractures were then analyzed at scanning electronic microscope. The results revealed that the one-step adhesive systems (G1 and G2) showed higher values of bond strength compared to the self-etching adhesive systems (G3 and G4). The fractures more commum were the adhesive type in the G3 and G4 groups, while in the G1 and G2 groups, 87% of the fractures were the adhesive and cohesion of resin types.

Resumo: A adesão longitudinal continua a representar um dos maiores desafios da Odontologia moderna. Uma nova proposta para o estabelecimento do equilíbrio da adesão aos tecidos dentários surge, baseada na observação dos resultados obtidos com a tecnologia Grander para revitalização da água. Objetiva-se com o estudo verificar a influência dessa tecnologia nas propriedades físicas de dois sistemas adesivos (convencional e autocondicionante) à partir da medição da tensão superficial e do ângulo de contato; e avaliar a formação e a qualidade da camada híbrida em dentina humana e bovina. A tensão superficial de quatro diferentes líquidos (água, Single Bond- 3M, Primer do Clearfil SE Bond -Kuraray, e Bond do Clearfil SE-Kuraray), foi medida antes e após a modificação pelo procedimento Grander em aparelho goniômetro (Ramé-hart). O ângulo de contato com três substratos distintos (placa de titânio, dentina humana e dentina bovina), foi medido para os quatro líquidos também antes e após a modificação pelo procedimento Grander, também em goniômetro. A formação e qualidade da camada híbrida, foi avaliada em MEV, a partir da confecção de corpos de prova dos substratos humano e bovino, devidamente embutidos, preparados em lixas de variada granulação até a exposição de dentina, submetidos ao procedimento adesivo (SB ou CSEB) normal ou grander modificado, recebendo ao final dupla camada de resina composta Z250-3M, fotopolimerizada por 40s. Após armazenamento em estufa bacteriológica por 24h, os procedimentos para análise ao MEV foram realizados (fixação, desidratação, secagem e metalização). A estatística de Análise de Variância ANOVA e Teste de Tukey 5% revelou que: houve redução estatisticamente significante da tensão superficial para todos os líquidos Grander modificados; houve redução estatisticamente... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: A long-lasting adhesion is still one of the biggest challenges of the modern Dentistry. A new approach to reaching the equilibrium of the adhesion to the dental tissues emerges based on the observation of the results obtained with the Grander Technology for revitalizing water. The aim of this study was to verify the influence of this technology on the physical properties of two adhesive systems (conventional and self-etching) through the measurement of the surface tension and of the contact angle and through the evaluation of the formed hybrid layer in human and bovine dentin. The surface tension of four different liquids (water, Single Bond - 3M, Clearfil SE primer - Kuraray and Clearfil SE bond - Kuraray) was measured before and after submitting these liquids to the Grander modifying unit, with the aid of a goniometer (Ramé-hart). The measurement of the contact angle of the liquids followed the same procedure using three distinct surfaces: titanium plate, human dentin and bovine dentin. The hybrid layer formed for both: non-modified and Grander modified adhesive systems, was evaluated in SEM. For this purpose human and bovine dentin samples were prepared. The teeth were fixed in acrylic resin and the dentin surfaces exposed and finished with various grit polishing paper discs. These dentin surfaces were then treated with the adhesive procedures (normal and Grander modified), before the placement of a double composite resin layer (Z250- 3M). After storage at 37oC for 24h, the SEM analysis were conducted. The data were submitted to ANOVA and Turkeys test 5%. The results showed statistically significant reduction for the surface tension of all liquids modified by the Grander technology, as well as for the contact angle in the human dentin. Statistically significant were also the results showing a thicker hybrid layer formation with the two adhesive systems when modified by the Grander... (Complete abstract click electronic access below)

Submitted by Renata Lopes (renatasil82@gmail.com) on 2015-12-07T17:01:41Z No. of bitstreams: 1 carolinaoliveiradeandradefurtado.pdf: 2894297 bytes, checksum: f089f62fc6081d6501fc211279a846ba (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2015-12-07T21:41:56Z (GMT) No. of bitstreams: 1 carolinaoliveiradeandradefurtado.pdf: 2894297 bytes, checksum: f089f62fc6081d6501fc211279a846ba (MD5) / Made available in DSpace on 2015-12-07T21:41:56Z (GMT). No. of bitstreams: 1 carolinaoliveiradeandradefurtado.pdf: 2894297 bytes, checksum: f089f62fc6081d6501fc211279a846ba (MD5) Previous issue date: 2015-04-29 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A clorexidina (CHX) é um agente antimicrobiano com capacidade de retardar a ação das metaloproteinases em tecido dentinário condicionado com ácido fosfórico. Mas, especula-se que os produtos de sua reação podem interferir química e fisicamente sobre os valores imediatos de resistência da união (TBS) dos adesivos autocondicionantes universais. O objetivo foi analisar a influência do tratamento da destina com solução de CHX a 2% previamente a aplicação dos adesivos autocondicionantes e universais sobre TBS. Superfícies oclusais de 20 molares humanos hígidos foram removidas para expor superfície dentinária média. Estes foram divididos em 8 grupos de acordo com o tipo de tratamento submetido: SEself- aplicação do sistema adesivo Clearfil SE Bond de acordo com as instruções do fabricante; SEself + CHX: aplicação prévia da clorexidina por 20 s seguido pela lavagem; SBself: aplicação do adesivo Scotchbond Universal de acordo com as instruções do fabricante no modo autocondicionante; SBself + CHX: aplicação prévia de CHX por 20 s seguido da secagem; SEtotal: condicionamento com ácido fosfórico a 35% por 15 s seguido da lavagem, secagem, primer ácido por 10 s, adesivo e fotoativação deste por 10 s; SEtotal + CHX: sequência técnica semelhante ao anterior, porém com aplicação de CHX após o condicionamento ácido; SBtotal: aplicação do adesivo de acordo com as instruções do fabricante no modo condiciomento ácido total; SBtotal + CHX: após o condicionamento com ácido fósforico, a CHX foi aplicada por 20 s seguido pela secagem e aplicação do adesivo. Blocos em resina composta com 5 mm foram construídos sobre as superfícies hibridizadas, seccionados em palitos de 1 mm2 e armazenados em água deionizada a 37 ºC por 24 horas. Após, os corpos de prova foram submetidos ao teste de microtração com velocidade de 1 mm/min até a fratura. As médias obtidas foram submetidas a ANOVA dois fatores e ao teste Tukey (p = 0.05). No modo autocondicionante, os grupos SEself (39,77 ± 11,56MPa) e SBself (40,84 ± 12,49MPa) não diferiram entre si e foram superiores estatisticamente aos grupos Seself + CHX (22,86 ± 5,18MPa) e Sbself + CHX (27,02 ± 5,58MPa), os quais não apresentam diferença estatística entre si. No modo com condicionamento ácido total, o grupo SBU + CHX apresentou a maior média (37,81 ± 11,69MPa), seguido pelos grupos SBtotal (31,53 ± 9,22MPa) e SEtotal+CHX (28,09 ± 4,2MPa). Já o grupo SEtotal (25,95 ± 5,43MPa) apresentou a menor média e foi inferior estatisticamente aos demais. Conclui-se que a aplicação prévia da CHX sobre a dentina interferiu na efetividade dos valores de resistência da união dos sistemas autocondicionantes e universais à dentina. / Chlorhexidine (CHX) is an antimicrobial agent with ability to slow down the action of metalloproteinases in dentin tissue conditioning with phosphoric acid. But, it is speculated that the products of their reaction may interfere chemically and physically on the immediate values of bond strength (TBS) of self-etching universal adhesives. The objective was to analyze the influence of treatment designed with CHX solution 2% prior to application of self-etch and universal adhesives on TBS. Occlusal surfaces of 20 sound human molars were removed to expose middle dentin surface. These were divided into 8 groups according to the type of treatment submitted: SEself- application of Clearfil SE Bond adhesive system according to the manufacturer's instructions; SEself + CHX: prior use of chlorhexidine for 20 s followed by washing; SBself: applying Scotchbond Universal according to the manufacturer's instructions in self-etching mode; SBself + CHX: previous application of CHX for 20 s followed by drying; SEtotal: phosphoric acid etching to 35% for 15 sec followed by washing, drying, primer acid for 10 seconds, adhesive and curing this for 10 seconds; SEtotal + CHX: Technical sequence similar to the above, but with application of CHX after acid etching; SBtotal: applying the adhesive according to the manufacturer's instructions in order condiciomento Total acid; SBtotal + CHX: after phosphoric acid etching, CHX was applied for 20 s followed by drying and application of the adhesive. Composite resin blocks with 5mm were built on the hybridized surfaces, cut into sticks of 1 mm2 and stored in deionized water at 37 °C for 24 hours. Afterwards, the samples were submitted to microtensile test speed of 1 mm/min until failure. The averages were submitted to two factors ANOVA and Tukey test (p = 0.05). In the self-etching mode, the SEself groups (39.77 ± 11,56MPa) and SBself (40.84 ± 12.49) did not differ statistically and were superior to SEself + CHX groups (22.86 ± 5,18MPa) and SBself + CHX (27.02 ± 5,58MPa), which have no statistical difference between them. On the total etching mode, SBU + CHX group had the highest average (37.81 ± 11,69MPa), followed by SBtotal groups (31.53 ± 9,22MPa) and SEtotal + CHX (28.09 ± 4, 2 MPa). Already SEtotal group (25.95 ± 5.43MPa) had the lowest average and was statistically lower to the other groups. It was concluded that the prior application of CHX on dentine interfered in the effectiveness of bond strength values of self-etching dentin and universal systems.

Neste estudo, o objetivo foi avaliar, in vitro, o comportamento de três sistemas adesivos dentários (SAD), sendo dois autocondicionantes Clearfil SE Bond Kuraray Co (CSEB) e Xeno III Dentsply (X-III) e um condicione e lave de 3 passos Scothbond Multi-Purpose Plus - 3M ESPE (SBMP), no que se refere à inibição de lesões recidivantes de cárie em dentina, frente à um desafio cariogênico bacteriano, que utilizou uma cepa de Streptococcus mutans. Além destes materiais, foi inserido no estudo um controle negativo (CN), o qual não recebeu tratamento adesivo. A amostra formada por terceiros molares humanos (n=40) foi preparada com cavidades Classe V e restaurada com a resina composta (RC) Z250 (3M ESPE), deixando-se um nicho na interface restauração/dente na parede gengival em dentina. Os quatro grupos experimentais (n=10) foram submetidos ao desafio cariogênico para o desenvolvimento das lesões durante 30 dias. Foi realizada em microscopia óptica de luz (MOL) a medição das variáveis: profundidade da lesão de parede, extensão da lesão de parede e profundidade da lesão externa e em MEV (Microscopia Eletrônica de Varredura) a análise morfológica das lesões de cárie formadas. Os dados referentes às lesões foram analisados através de Análise de Variância, testes auxiliares, além do Teste de Brown e Forsythe, com grau de significância de 5%. A metodologia adotada foi capaz de desenvolver lesões externas e de parede e de padronizar uma fenda entre restauração/dente. Em relação às variáveis estudadas, concluiu-se que o CSEB apresentou menores lesões de parede em profundidade e extensão do que os demais SAD, e que os resultados do X-III foram similares estatisticamente ao SBMP para as mesmas variáveis. Quanto a profundidade da lesão externa, todos os SAD tiveram comportamento semelhante. / The aim of this study was to evaluate the in vitro behavior of three dental adhesive systems (DAS), namely the two self etching Clearfil SE Bond Kuraray Co (CSEB) and Xeno III Dentsply (X-III) as well as the three-step etch and rinse Multi-Purpose Plus 3M ESPE (SBMP), concerning the inhibition of secondary dentine caries in the face of a bacterial cariogenic challenge using Streptococcus mutans. Besides the aforementioned material, a negative control group (NC) which did not receive any adhesive treatment was included in this study. The sample, which consisted of human third molars (n=40), in which class-V cavities prepares were restored with the composite resin (CR) Z250 (3M ESPE). An interfacial gap was left between teeth and restorations in the dentinal gingival wall. The four experimental groups (n=10) were exposed to a cariogenic challenge during 30 days. Light Optical Microscopy (LOM) was used to measure wall caries lesion depth, wall caries lesion extension and outer caries lesion depth. SEM (Scanning Electron Microscopy) was the method chosen for the morphological analysis of the formed carie lesions. The data regarding lesions was analyzed through Analysis of Variance and Component of Variance Model in addition to the Brown-Forsythe test at a 5% significance level. The adopted methodology could develop external and wall lesions, also standardizing a gap between restorations and teeth. About the studied variables, it was possible to conclude that CSEB presented the smallest wall lesions both in depth and extension, and the X-III and SBMP results were statistically similar concerning the same variables. Regarding outer lesion depth, all DAS showed similar behaviour.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-08-31T20:05:30Z No. of bitstreams: 1 Tese-AdrianaMaraAraujoLeal.pdf: 1605470 bytes, checksum: 5e809d0da87d46e2077716ab7023a4a6 (MD5) / Made available in DSpace on 2017-08-31T20:05:30Z (GMT). No. of bitstreams: 1 Tese-AdrianaMaraAraujoLeal.pdf: 1605470 bytes, checksum: 5e809d0da87d46e2077716ab7023a4a6 (MD5) Previous issue date: 2016-02-29 / FAPEMA / Objectives: To evaluate the effect of airborne-particle abrasion with niobium phosphate bioglass (NbG) microparticles on the bond strength (µTBS) and longevity of an adhesive system to different dentin substrates. Methods and Materials: Caries-free molars were used in this study. The dentin surfaces were evaluated in three groups: (1) Control – Healthy Dentin; (2) Partial removal of carious tissue; (3) complete removal of carious tissue. Half the teeth in each group were submitted to airborne-particle abrasion with NbG microparticles (15s/1cm/5bar). After this, the adhesive Clearfil S3 was applied and composite buildups were constructed incrementally; and specimens were longitudinally sectioned to obtain bonded sticks (1.0 mm2) to be tested in tension (0.5 mm/min) immediately or after 6 months of storage in water. The fracture patterns were evaluated by stereomicroscope (40x) and then by scanning electron microscopy (SEM). The data were analyzed by the Kruskal-Wallis (post-hoc Dunn) and Mann-Whitney tests (α=0.05). Results: Healthy dentin showed the highest bond strength (µTBS). Airborne-particle abrasion with NbG increased the µTBS values in the complete caries removal group. The bond strength values in the 24-hr period were higher than those at 6 months. In the majority of the specimens the fracture mode was adhesive/ mixed. Conclusion: The authors concluded that airborne-particle abrasion on dentin with NbG particles increased the µTBS in the group in which carious dentin was completely removed. / Objetivo: Avaliar o efeito do jateamento de micropartículas de vidro niobofosfato (NbG) na resistência de união (RU) e na longevidade de um sistema adesivo em diferentes substratos dentinários. Dezoito molares extraídos livres de cárie foram usados. As superfícies de dentina foram avaliadas em três grupos: (1) Controle – Dentina Sadia; (2) Remoção parcial do tecido cariado; (3) Remoção total do tecido cariado. Metade dos dentes de cada grupo sofreu um jateamento com partículas de NbG (15s/1cm/5bar). Em seguida o adesivo Clearfil S3 Bond Plus foi aplicado e uma coroa de resina composta foi construída. Os dentes foram seccionados para obtenção dos espécimes (1,0 mm2) e submetidos ao teste de microtração (0,5 mm/min) imediatamente e após 6 meses de estocagem em água. Os padrões de fratura foram avaliados usando estereomicroscópio (40x) e levados ao microscópio eletrônico de varredura (SEM). Os dados foram analisados pelos testes Kruskal-Wallis (pos-hoc Dunn) e Mann-Whitney (α=0.05). Resultados: A dentina sadia apresentou os maiores valores de RU. O jateamento com NbG aumentou os valores de RU no grupo remoção total. Os valores de RU no período de 24h foram superiores ao de 6 meses. A maioria das fraturas dos espécimes foi adesiva/mista. Conclusão: Os autores concluíram que o jateamento à dentina com partículas NbG aumentou a RU no grupo onde a dentina cariada foi totalmente removida.

El objetivo de este estudio fue evaluar el efecto sobre la fuerza adhesiva (SBS), adhesivo remanente, y superficie del esmalte del recementado de brackets nuevos en la misma superficie de esmalte utilizando distintos métodos de acondicionamiento del esmalte.Utilizamos 135 incisivos bóvinos. Los brackets fueron cementados al esmalte con: (1)acido-fosfórico al 37%, (2)ácido-fosfórico al 37% (antes del primer cementado pero no en los siguientes cementados), (3)Transbond-Plus-Self-Etching-Primer® (TSEP) y (4)acondicionador que no precisa lavado (NRC). Los brackets fueron cementados y descementados tres veces utilizando el mismo procedimiento de acondicionamiento con la excepción del grupo 2 donde no se volvió a grabar con ácido-fosfórico al 37% en la segunda ni tercera secuencias de cementado. SBS y el adhesivo remanente fueron evaluados para cada descementado. Se realizaron observaciones al MEB para cada secuencia de acondicionamiento. Se realizó el análisis estadístico utilizando ANOVA, test de Mann-Whitney, y test de Kruskal-Wallis. / The aims of this study were to evaluate the effect on shear bond strength (SBS), adhesive remnant, and enamel surface of repeated bonding of new brackets on the same tooth using different methods of enamel conditioning.135 bovine incisors were used. Brackets were bonded to enamel using oneof the following conditioning procedures: (1) 37% phosphoric-acid, (2) 37% phosphoric-acid (prior to first bond but not for further bonds), (3) Transbond Plus Self Etching Primer® (TSEP), and (4) non-rinse-conditioner (NRC). Brackets were sequentially bonded and debonded three timesfollowing the same conditioning procedure with the exception of group 2 where 37% phosphoric-acid was not reapplied prior to the second and third bonding sequences. SBS and adhesive remnant were evaluated for each debond. SEM observations were made for each conditioning sequence. Statistical analysis was undertaken using ANOVA, Mann-Whitney, and Kruskal-Wallis tests.

No description available.