ABSTRACT
Introduction: The alveolar bone resorption that occurs after tooth loss leads to maladaptation of prostheses over the mucosa, causing discomfort to the patient. However, these maladaptations can be solved by prosthesis relining. Objective: The aim of this study was to discuss based on the literature, the relining of complete and partial removable dentures. Literature review: Dentistry makes use of relining materials that can be either rigid or resilient, having a temporary or permanent characteristic. However, to obtain a satisfactory result, the knowledge of their indications, contraindications, advantages, disadvantages is required, in addition to the characteristics and types of materials. Patients should be aware of the importance of constant monitoring, or even the need to reline their dentures, as it is not possible to determine the biological tolerance of each individual. Conclusion: The installation and proservation phases become essential to minimize bone resorption, and also to achieve rehabilitative treatment success.
ABSTRACT
ABSTRACT Introduction and Objective: This study aimed to evaluate the effect of Er:YAG (L) and diamond drills (DD) on: 1) the microshear bond strength (MPa); 2) the adhesive interface of two-step (TS) - Adper Scotchbond Multipurpose and one-step (OS) adhesives - Adper EasyOne, both from 3M ESPE. Material and methods: According to the preparation condition and adhesives, the samples were divided into four groups: DD_TS (control); DD_OS; L_TS and L_OS. 60 bovine incisors were randomly divided into experimental and groups: 40 for microshear bond strength (n = 10) and 20 for the adhesive interface morphology [6 to measure the thickness of the hybrid layer (HL) and length of tags (t) by CLSM (n = 3); 12 to the adhesive interface morphology by SEM (n = 3) and 2 to illustrate the effect of the instruments on dentine by SEM (n = 1)]. To conduct the microshear bond strength test, four cylinders (0.7 mm in diameter and 1 mm in height with area of adhesion of 0.38 mm) were constructed with resin composite (Filtek Z350 XT - 3M ESPE) on each dentin surface treated by either L or DD and after adhesives application. Microshear bond strength was performed in universal testing machine (EMIC 2000) with load cell of 500 kgf and a crosshead speed of 0.5 mm / min. Adhesive interface was characterized by thickness of hybrid layer (HL) and length of tags (t) in nm, with the aid of UTHSCSA ImageTool software. Results: Microshear bond strength values were: L_TS 34.10 ± 19.07, DD_TS 24.26 ± 9.35, L_OS 33.18 ± 12.46, DD_OS 21.24 ± 13.96. Two-way ANOVA resulted in statistically significant differences only for instruments (p = 0.047). Mann-Whitney identified the instruments which determined significant differences for HL thickness and tag length (t). Concerning to the adhesive types, these differences were only observed for (t). Conclusion: It can be concluded that 1) laser Er:YAG results in higher microshear bond strength values regardless of the adhesive system (TS and OS); 2) the tags did not significant affect the microshear bond strength; 3) the adhesive interface was affected by both the instruments for cavity preparation and the type of adhesive system used.
ABSTRACT
O objetivo deste trabalho foi avaliar a resistência de união ao microcisalhamento de diferentes sistemas adesivos autocondicionantes de dois passos e passo único, com graus de acidez distintos, em substrato dentinário normal e hipermineralizado artificialmente. Sessenta e cinco (n = 65) incisivos bovinos hígidos foram selecionados, sendo cinqüenta e sete (n = 57) para o teste de resistência de união ao microcisalhamento e oito (n = 8) para a observação da interface adesiva em microscopia eletrônica de varredura (MEV). Os dentes tiveram suas raízes removidas com o auxílio de um motor elétrico e disco diamantado. As coroas tiveram sua superfície vestibular desgastada com o objetivo de expor a superfície dentinária plana, sendo os dentes divididos aleatoriamente em dois diferentes grupos, de acordo com o tipo de dentina: normal (N/ n = 28) e hipermineralizada artificialmente (H/ n = 29). O conjunto H recebeu tratamento para hipermineralização e um espécime foi selecionado aleatoriamente para observação em MEV para a confirmação do procedimento de hipermineralização. Cada coroa foi incluída em um cilindro de PVC com o auxílio de resina acrílica autopolimerizável. Cada grupo foi dividido em 4 subgrupos de acordo com o sistema adesivo autocondicionante empregado: Clearfil SE Bond (n=7) suave de dois passos, Adhese (n = 7) moderado de dois passos, Adper Easy One (n = 7) suave de passo único, Optibond All in One (n = 7) moderado de passo único. Sobre essa superfície foram inseridos e fotopolimerizados cilindros de resina composta (FiltekTM Z350 XT - 3M ESPE). Após período de armazenagem de 24 horas em ambiente úmido a 37°C (± 1°C), foram realizados os testes de microcisalhamento em máquina de ensaios mecânicos com velocidade de 0,5 mm/min até à fratura dos espécimes. A fim de verificar a presença de interface e/ou a aparência de tags de resina, um um espécime de cada grupo foi preparado para avaliação da interface adesiva em MEV. As diferenças entre os grupos foram determinadas utilizando os testes ANOVA e Bonferroni (p<0,05). Os valores de resistência de união ao microcisalhamento foram Clearfil=15,65 ± 6,18, AdheSE=14,71 ± 10,36, Easy One=21,92 ± 6,40, OptiBond=28,43 ± 6,55 para dentina normal e Clearfil=20,96 ± 8,06, AdheSE=17,23 ± 5,16, Easy One=31,79 ± 8,31, OptiBond=23,29 ± 3,66 para dentina hipermineralizada, sendo a diferença significante apenas para o adesivo Adper Easy One (p<0,05). Ao analisar os fatores adesivo, dentina e interação foi encontrada diferença significativa apenas para o adesivo (p=0,0002), concluindo que a resistência ao microcisalhamento é dependente do fator adesivo, mas não em relação ao tipo de dentina ou interação. Com base nos resultados obtidos pode-se concluir que sistemas adesivos autocondicionantes com maior grau de acidez não apresentam necessariamente maior resistência ao microcisalhamento em dentina hipermineralizada
The aim of this study was to evaluate the microshear bond strength of different self-etching two-step and all-in-one adhesive systems, with different acid concentrations to sound and artificially hypermineralized dentin. Sixty-five (n = 65) healthy bovine incisors were selected, fifty-seven (n = 57) to test the microshear bond strength and eight (n = 8) to observe the presence of adhesive interface with scanning electron microscopy (SEM). Teeth have roots removed using an electric motor and diamond disc. Vestibular surface were ground flat to expose a flat dentin surface, the teeth were divided randomly into two different groups according the type of dentin: sound (N / n = 28) or artificially hypermineralized (H / n = 29). The set H received hypermineralizing treatment and a specimen was selected randomly to observe the procedure with SEM. Each crown was included in a PVC cylinder using acrylic resin. Each group was divided into 4 subgroups according to dentin adhesive systems: Clearfil SE Bond (n = 7) - mild two steps, AdheSE (n = 7) - moderate two steps, Adper Easy One (n = 7) - mild all-in-one, Optibond All in One (n = 7) - moderate all-inone. Then were inserted and cured resin cylinders (Filtek Z350 XT - 3M ESPE) at the surface. After 24 hours storage at 37 ° C (± 1°C), for humid environment, microshear was taked using mechanical testing machine with 0.5 mm/min speed until fracture of the specimens. For analysis the presence of an interface and/or appearance of resin tags, a specimen of each group was prepare for evaluating the adhesive interface with SEM. Bond strengths data were subjected to ANOVA and Bonferroni (p<0.05) test. The bond strength values were Clearfil = 15.65 ± 6.18, AdheSE = 14.71 ± 10.36, Easy One = 21.92 ± 6.40, OptiBond = 28.43 ± 6.55 to sound dentin and Clearfil = 20.96 ± 8.06, AdheSE = 17.23 ± 5.16, Easy One = 31.79 ± 8.31, OptiBond = 23.29 ± 3.66 to hypermineralized dentin, a statistically significant difference was found only for Adper Easy One (p <0.05). By analyzing adhesive, dentin and interaction factors was found significant difference only for adhesive (p = 0.0002), concluding that microshear bond strength is adhesive factor dependent, but not for the type of dentin or interaction. Based on the obtained results it can be concluded that adhesive systems with higher acidity not necessarily improve greater microshear bond strength to hypermineralized dentin