Influence of sonic vibration and cement type on the bond strength of fiberglass posts after aging / Influencia de la vibración sónica y el tipo de cemento en la fuerza de unión de los postes de fibra de vidrio después del envejecimiento

Introduction: This study evaluated the influence of sonic vibration and thermocycling on the bond strength of fiberglass posts using conventional dual-cured and self-adhesive resin cements. Material and Methods: Ninety-six single-rooted endodontically treated teeth were divided randomly into eight groups according to the cement used (dual-cured or self-adhesive resin cement), use of sonic vibration during post accommodation, and aging conditions (24h in distilled water or 5,000 thermal cycles). The fiberglass posts (White Post DC1, FGM) were cleaned with alcohol, treated with silane and cemented with dual-cured (Allcem Core, FGM) or with self-adhesive resin cement (seT, SDI). For groups in which sonic vibration was used, the posts were accommodated, and sonic vibration was applied for 10 s using a special tip placed on top of the post (Sonic Smart Device, FGM). Pull-out tests were performed after storage in distilled water for 24h at 37°C or after thermocycling (5000 cycles, at 5°C and 55°C). The results were evaluated using three-way ANOVA and Tukey's test (α=0.05). Results: Significant differences were not observed between the bond strengths of dual-cured (87.93±41.81 N) and self-adhesive cement (82.53±41.43 N). Bond strength for the sonic vibration groups (100.36±42.35 N) was significantly higher than for groups without sonic vibration (70.13±34.90 N). There were significant differences between specimens subjected to thermocycling (98.33±39.42 N) and those stored for 24h in distilled water (72.16±39.67 N). Conclusion: It can be concluded that both sonic vibration and thermocycling significantly improved bond strength of fiberglass posts with the two evaluated resin cements.

Introducción: Este estudio evaluó la influencia de la vibración sónica y el termociclado en la fuerza de unión de los postes de fibra de vidrio utilizando cementos de resina autoadhesivos y de curado dual convencionales Material y Métodos: Se dividieron aleatoriamente noventa y seis dientes tratados endodónticamente de raíz única en ocho grupos según el cemento utilizado (cemento de resina de curado dual o autoadhesivo), el uso de vibración sónica durante la acomodación posterior y las condiciones de envejecimiento (24 horas agua destilada o 5.000 ciclos térmicos). Los postes de fibra de vidrio (White Post DC1, FGM) se limpiaron con alcohol, se trataron con silano y se cementaron con cemento de curado dual (Allcem Core, FGM) o con cemento de resina autoadhesivo (seT, SDI). Para los grupos en los que se utilizó vibración sónica, se acomodaron los postes y se aplicó la vibración sónica durante 10 s utilizando una punta especial colocada en la parte superior del poste (Sonic Smart Device, FGM). Las pruebas de extracción se realizaron después del almacenamiento en agua destilada durante 24 horas a 37ºC o después del termociclado (5000 ciclos, a 5ºC y 55ºC). Los resultados se evaluaron mediante ANOVA de tres vías y la prueba de Tukey (α = 0.05). Resultados: No se observaron diferencias significativas entre las resistencias de adhesión del cemento de curado dual (87,93 ± 41,81 N) y el cemento autoadhesivo (82,53 ± 41,43 N). La fuerza de unión para los grupos de vibración sónica (100,36 ± 42,35 N) fue significativamente mayor que para los grupos sin vibración sónica (70,13 ± 34,90 N). Hubo diferencias significativas entre los especímenes sometidos a termociclado (98,33 ± 39,42 N) y los almacenados durante 24 h en agua destilada (72,16 ± 39,67 N). Conclusión: Se puede concluir que tanto la vibración sónica como el termociclado mejoraron significativamente la fuerza de unión de los postes de fibra de vidrio con los dos cementos de resina evaluados.

Effect of Sonic Vibrations on Bond Strength of Fiberglass Posts Bonded to Root Dentin

Abstract Sonic vibrations may improve the bond strength and durability of fiberglass posts by improving adhesive penetration into dentin as well as the cement flow. The objective of this study was to evaluate the effect of sonic vibrations on the bond strength between fiberglass posts and root dentin using the pull-out test. Bovine roots were endodontically treated and divided randomly into four groups (n=12): Group C - conventional cementation (control); Group SA - sonic vibration (Smart Sonic Device, FGM) of the adhesive system and conventional post accommodation; SP group - conventional adhesive application and sonic vibration of the post during accommodation; and SASP - sonic vibration of the system adhesive and the post during accommodation. The posts were cleaned, treated with a silane and adhesive system (Ambar, FGM), and cemented with a dual-cured resin cement (Allcem Core, FGM). After 24 h, the specimens were subjected to mechanical tests and failure analyses. Representative specimens were analyzed by a scanning electron microscope to observe the cementation line. The results were analyzed using ANOVA and Tukey's test (a=5%). The bond strengths were as follows: SASP (90.9±27.1 N), C (121.4±60.6 N), SA (127.6±31.8 N) and SP (156.4±41.3 N). The use of sonic vibrations during the application of adhesive or post cementation separately did not affect the bond strength but had a negative effect when used for both procedures.

Resumo Vibrações sônicas podem melhorar a resistência e a durabilidade da união de pinos de fibra de vidro, melhorando a penetração do sistema adesivo à dentina, bem como o escoamento do cimento. O objetivo deste estudo foi avaliar o efeito da vibração sônica na resistência de união de pinos de fibra de vidro à dentina radicular, através de ensaio pull out. Raízes bovinas tratadas endodonticamente foram preparadas e divididas aleatoriamente em quatro grupos (n=12): Grupo C - cimentação convencional, (controle); Group SA - vibração sônica (Smart Sonic Device(r), FGM) do sistema adesivo e assentamento convencional do pino; grupo SP - aplicação convencional do sistema adesivo e vibração sônica no assentamento do pino; e SASP - vibração sônica do sistema adesivo e no assentamento do pino. Os retentores foram limpos, tratados com silano e sistema adesivo (Ambar, FGM) e cimentados com cimento resinoso dual (Allcem Core, FGM). Após 24 h as amostras foram submetidas ao teste mecânico e análise de falha. Amostras representativas foram avaliadas sob microscópio eletrônico de varredura, para avaliação da linha de cimentação. Os resultados foram analisados por meio de análise de variância e teste de Tukey (a=5%). Os resultados obtidos foram: SASP (90,9±27,1 N, C (121,4±60,6 N), SA (127,6±31,8 N) e SP (156,4±41,3 N). A vibração sônica para aplicação apenas do sistema adesivo ou pino não afetou a resistência de união, entretanto interferiu negativamente quando utilizada para ambos procedimentos.