Effect of a one-step self-etch adhesive on endogenous dentin matrix metalloproteinases.

Degradation of the hybrid layer created in dentin by dentin adhesives is caused by enzyme activities present within the dentin matrix that destroy unprotected collagen fibrils. The aim of the present study was to evaluate the effect of a one-step self-etch adhesive system on dentinal matrix metalloproteinases 2 and 4 (MMP-2 and MMP-9, respectively) using in situ zymography and an enzymatic activity assay. The null hypothesis tested was that there are no differences in the activities of dentinal MMPs before and after treatment with a one-step adhesive system. The MMP-2 and MMP-9 activities in dentin treated with the one-step adhesive, Adper Easy Bond, were quantified using an enzymatic activity assay system. The MMP activities within the hybrid layer created by the one-step adhesive tested were also evaluated using in situ zymography. The enzymatic assay revealed an increase in MMP-2 and MMP-9 activities after treatment with adhesive. In situ zymography indicated that gelatinolytic activity is present within the hybrid layer created with the one-step self-etch adhesive. The host-derived gelatinases were localized within the hybrid layer and remained active after the bonding procedure. It is concluded that the one-step self-etch adhesive investigated activates endogenous MMP-2 and MMP-9 with the dentin matrix, which may cause collagen degradation over time.

Co-distribution of cysteine cathepsins and matrix metalloproteases in human dentin.

It has been hypothesized that cysteine cathepsins (CTs) along with matrix metalloproteases (MMPs) may work in conjunction in the proteolysis of mature dentin matrix. The aim of this study was to verify simultaneously the distribution and presence of cathepsins B (CT-B) and K (CT-K) in partially demineralized dentin; and further to evaluate the activity of CTs and MMPs in the same tissue. The distribution of CT-B and CT-K in sound human dentin was assessed by immunohistochemistry. A double-immunolabeling technique was used to identify, at once, the occurrence of those enzymes in dentin. Activities of CTs and MMPs in dentin extracts were evaluated spectrofluorometrically. In addition, in situ gelatinolytic activity of dentin was assayed by zymography. The results revealed the distribution of CT-B and CT-K along the dentin organic matrix and also indicated co-occurrence of MMPs and CTs in that tissue. The enzyme kinetics studies showed proteolytic activity in dentin extracts for both classes of proteases. Furthermore, it was observed that, at least for sound human dentin matrices, the activity of MMPs seems to be predominant over the CTs one.

Two-year clinical evaluation of chlorhexidine incorporation in two-step self-etch adhesive.

OBJECTIVES: The aim of this 24-month double-blind randomized paired-tooth clinical study was to evaluate the 2-year clinical performance of two self-etch adhesives containing or not chlorhexidine digluconate (CHX) in non-carious cervical lesions (NCCLs). METHODS: Twenty-two patients, with at least four NCCLs, participated in this study. After sample size calculation, 126 restorations were assigned to one of the following groups: CSE--Clearfil SE Bond (Kuraray); CSE/CHX--Clearfil SE Bond+CHX; ADS--AdheSE (Ivoclar Vivadent); and ADS/CHX--AdheSE+CHX. The composite resin Filtek Z-250 composite (3M ESPE) was placed incrementally by one expert operator. The restorations were evaluated at baseline and after 2 years using the modified USPHS criteria. Statistical analyses were performed with Friedman repeated measures ANOVA by rank and Fisher exact test for significance in each pair (α=0.05). RESULTS: No significant difference was observed between baseline and 2-year for any criteria when adhesives with and without the addition of CHX were compared (p>0.05). ADS and ADS/CHX resulted in lower retention rates (82% on average) than CSE and CSE/CHX (97%) (p=0.02). CONCLUSIONS: The inclusion of CHX into the primer of both self-etch systems did not add clinical advantages over the 2-year period. Clearfil SE Bond resulted in better retention rate than AdheSE. CLINICAL SIGNIFICANCE: It is more important to choose a gold standard self-etch adhesive, like a Clearfil SE Bond, than to consider the inclusion of CHX in the self-etch adhesives.

Adhesive performance of a multi-mode adhesive system: 1-year in vitro study.

OBJECTIVES: The aim of this study was to investigate the adhesive stability over time of a multi-mode one-step adhesive applied using different bonding techniques on human coronal dentine. The hypotheses tested were that microtensile bond strength (µTBS), interfacial nanoleakage expression and matrix metalloproteinases (MMPs) activation are not affected by the adhesive application mode (following the use of self-etch technique or with the etch-and-rinse technique on dry or wet dentine) or by ageing for 24h, 6 months and 1year in artificial saliva. METHODS: Human molars were cut to expose middle/deep dentine and assigned to one of the following bonding systems (N=15): (1) Scotchbond Universal (3M ESPE) self-etch mode, (2) Scotchbond Universal etch-and-rinse technique on wet dentine, (3) Scotchbond Universal etch-and-rinse technique on dry dentine, and (4) Prime&Bond NT (Dentsply De Trey) etch-and-rinse technique on wet dentine (control). Specimens were processed for µTBS test in accordance with the non-trimming technique and stressed to failure after 24h, 6 months or 1 year. Additional specimens were processed and examined to assay interfacial nanoleakage and MMP expression. RESULTS: At baseline, no differences between groups were found. After 1 year of storage, Scotchbond Universal applied in the self-etch mode and Prime&Bond NT showed higher µTBS compared to the other groups. The lowest nanoleakage expression was found for Scotchbond Universal applied in the self-etch mode, both at baseline and after storage. MMPs activation was found after application of each tested adhesive. CONCLUSIONS: The results of this study support the use of the self-etch approach for bonding the tested multi-mode adhesive system to dentine due to improved stability over time. CLINICAL SIGNIFICANCE: Improved bonding effectiveness of the tested universal adhesive system on dentine may be obtained if the adhesive is applied with the self-etch approach.

Resistência de união de um sistema restaurador à base de silorano ao esmalte bovino / Bond strength of a Silorane-based composite to bovine enamel

O objetivo do presente estudo foi avaliar a resistência de união ao esmalte bovino de um sistema adesivo para compósitos à base de silorano, com e sem condicionamento prévio. Para isso, foram selecionados 12 incisivos bovinos com superfície de esmalte planificada e, então, divididos em dois grupos: Grupo 1 (P90) - realizado um platô em esmalte com o sistema restaurador P90; Grupo 2 (P90A) - realizado um platô com condicionamento ácido prévio à utilização do sistema adesivo, utilizando ácido fosfórico a 37% por 15s. Os espécimes (n=6) foram seccionados nos eixos "x" e "y" para obtenção de palitos para o teste de microtração com velocidade de 0,5mm/min. Os dados obtidos foram submetidos aos testes ANOVA One-way e Tukey. Os testes de microtração mostraram um aumento na resistência de união, quando utilizado o condicionamento ácido prévio ao sistema adesivo adotado no estudo (p<0,05). Concluiu-se que o condicionamento prévio com ácido fosfórico a 37% aumentou a resistência de união do sistema restaurador à base de silorano ao esmalte bovino.

The purpose of this study was to evaluate the bond strength produced by a Silorane-based restorative system to enamel with or without prior acid etching. Twelve bovine incisors were selected. Then, the enamel was planned. The teeth were divided into two groups: Group 1 - a plateau was built in the enamel planned with P90 system (P90); Group 2 - a plateau was built in the enamel with prior etching using 37% phosphoric acid for 15s (P90A). Specimens (n=6) were sectioned in enamel/composite sticks to microtensile testing. The cross-sectional area of the sticks was measured. Beams were pulled until failure and bond strength was calculated. Data were statistically analyzed using ANOVA One-way and Tukey (p=0,05). Microtensile bond strength showed higher values to group 2 (P90A), that used prior etching to the adhesive system tested in the study. In conclusion prior etching with phosphoric acid increased microtensile bond strength values of the Silorane-based composite on bovine enamel.

Effect of carbodiimide (EDC) on the bond stability of etch-and-rinse adhesive systems.

OBJECTIVE: Recent studies supported the use of protein cross-linking agents during bonding procedures to inactivate endogenous dentin proteases, preventing dentin collagen degradation thus improving bond durability. The aim of this study was to evaluate the effect of a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-containing conditioner on the stability of the adhesive interface created by two etch-and-rinse adhesives. METHODS: Human dentin was etched with 35% phosphoric acid, treated with 0.3M EDC-containing conditioner followed by a three-step or a two-step etch-and-rinse adhesive. Adhesives were applied to control specimens without EDC pre-treatment. Specimens were subjected to microtensile bond strength test and pulled to failure after 24h or 1 year of storage and interfacial nanoleakage expression was evaluated and quantified by light microscopy. Additionally, to investigate endogenous dentin matrix metalloproteinase activity a zymographic assay was performed on protein extracts obtained from phosphoric-acid-etched dentin powder with or without EDC treatment. RESULTS: The use of the EDC-containing conditioner did not affect immediate bond strength to dentin but contributed to preserve the bond strength after 1 year (p<0.05) for both tested adhesives. No difference was found in the interfacial nanoleakage expression that increased after aging irrespective from the treatment. EDC pre-treatment inhibited dentin endogenous MMPs as assayed with the zymography. SIGNIFICANCE: In conclusion, the results of the study provide proof that EDC can produce long-term inactivation of MMPs in acid-etched dentin matrices contributing to bond strength preservation over time. Future studies are needed to support the use of EDC in vivo.

Resin-dentin bonds of etch-and-rinse adhesives to alcohol-saturated acid-etched dentin.

PURPOSE: To evaluate the effect of the alcohol wet-bonding technique on bond performance of the adhesive interface produced by two-step etch-and-rinse adhesive systems. MATERIALS AND METHODS: Composite buildups were bonded to sectioned human third molars using Adper Single Bond 2 (SB) bonded to acid-etched dentin saturated with water (control) or ethanol, or XP Bond (XP) bonded to acid-etched dentin saturated with water (control) or tert-butanol. A simplified dentin dehydration protocol was performed using 100% ethanol or 99.5% tert-butanol directly applied to dentin for 60 s. Specimens were cut into nontrimming dentin-composite beams that were divided equally in two subgroups: immediately tested and after immersion in 10% NaOCl solution for 1 h. Specimens were tested in tension at a crosshead speed of 1 mm/ min until failure, and the failure mode was evaluated. Data were statistically analyzed with three-way ANOVA and Tukey's test (α = 0.05). Additional dentin disks were bonded using the same groups tested and examined for leakage under light microscopy after immersion in ammoniacal silver nitrate solution. RESULTS: The SB control group showed significantly higher bond strength values than did SB used on ethanol saturated dentin (p < 0.05); this tendency was confirmed by the silver nitrate deposition. The use of tert-butanol did not influence XP bond strength values (p > 0.05) or silver nitrate penetration. NaOCl solution significantly reduced the bond strength of all groups tested (p < 0.05) and also increased the interfacial silver nitrate penetration. CONCLUSION: The simplified alcohol wet-bonding technique used in the present study was not able to improve resin/dentin bond performance for simplified etch-and-rinse adhesive systems.

Avaliação da infiltração marginal em restaurações com compósitos à base de metacrilato e à base de silorano / Evaluation of marginal leakage on restorations of methacrilate and silorane-based composites

Objetivo: O objetivo deste estudo in vitro foi avaliar o nível de infiltração marginal em restaurações realizadas com sistemas restauradores à base de metacrilato e à base de silorano. Materiais e método: Cavidades classe V em forma de caixa (4 x 4 x 2mm) foram preparadas na junção cemento-esmalte nas faces vestibular, lingual, mesial e distal com margens em esmalte e dentina de vinte molares humanos hígidos. Os dentes foram divididos aleatoriamente em dois grupos e restaurados da seguinte forma: Grupo 1 (G1) - Clearfil SE, aplicado se-gundo as instruções do fabricante e restaurado com re-sina composta Filtek Z250, e Grupo 2 (G2) - P90 Bond, aplicado segundo as instruções do fabricante e restau-rado com resina composta Filtek P90. Resina composta foi aplicada em incremento único e fotopolimerizada por 40s. Os espécimes foram imersos em solução de azul de metileno a 2% por 4h e seccionados longitu-dinalmente no centro da restauração. A penetração de corante na interface adesiva foi avaliada usando-se lupa esterioscópica e escores de 0 a 3 foram atribuídos às margens de esmalte e dentina. A significância dos dados foi analisada utilizando-se os testes estatísticos Kruskall Wallis e Student-Newman-Keuls. Resultados: Não houve diferença estatística entre os dois sistemas restauradores testados tanto nas margens de dentina (P = 0,19) quanto nas margens de esmalte (P = 0,97). Conclusão: Não houve diferença na capacidade sela-dora dos materiais restauradores testados.

Restoring esthetics in eroded anterior teeth: a conservative multidisciplinary approach.

Consuming a highly acidic diet can lead to erosion or excessive wear of dental hard tissues, resulting in the need for oral rehabilitation. Previously, a severely eroded dentition could be rehabilitated only by extensive crown and bridge placement or by removable partial dentures. However, developments in adhesive dentistry have made it possible to restore the esthetics and function of eroded teeth in a minimally invasive manner. This case report presents a conservative, multidisciplinary approach to restoring severe wear due to dental erosion using proper techniques and materials.

Resistência de união de pinos de fibra de vidro à dentina em diferentes regiões do canal radicular / Bond strength of glass fiber posts to dentin in different regions of the root canal

OBJETIVO: Avaliar a resistência de união da interface adesiva de pinos de fibra de vidro (Reforpost nº 3 - Angelus) e dentina radicular. MÉTODOS: Vinte e quatro raízes de dentes humanos foram tratadas endodonticamente e desobstruídas até uma profundidade de 9mm e o pino cimentado com um dos três sistemas de fixação descritos a seguir (n = 8): Grupo 1 - sistema Single Bond 2 (3M ESPE, St. Paul, MN, EUA) / RelyX ARC (3M ESPE, St. Paul, MN, EUA); Grupo 2 - sistema ED Primer/Panavia 21 (Kuraray Medical Inc. Kurashiki, Japão); Grupo 3 - cimento RelyX Unicem (3M ESPE/AG. Seefeld, Alemanha). As raízes foram seccionadas em três porções correspondentes aos terços cervical, médio e apical. Os espécimes foram submetidos aos testes de push-out e os valores de resistência de união à análise de variância (ANOVA) e ao teste de Tukey (p< 0,05). RESULTADOS: Somente o Grupo 2 apresentou diferença estatística em relação aos terços, tendo o apical apresentado menor média. Para o terço cervical, o Grupo 3 apresentou maiores valores de resistência de união que o Grupo 2, tendo sido Grupo 1 estatisticamente semelhante aos outros dois materiais. Para os terços médio e apical, Grupo 2 apresentou resistência de união menor que Grupo 1 e Grupo 3, sendo estes estatisticamente iguais entre si. CONCLUSÃO: Os cimentos de presa dual (RelyX ARC, 3M ESPE, St. Paul, MN, EUA e RelyX Unicem, 3M ESPE, St. Paul, MN, EUA) promoveram maior resistência de união entre o pino endodôntico e as paredes do canal radicular do que o cimento quimicamente ativado (Panavia 21, Kuraray Medical Inc., Kurashiki, Japão).

OBJECTIVE: This study assessed the bond strength of the adhesive interface of fiber glass posts (Reforpost nº 3 - Angelus) to root dentin. METHODS: Twenty-four roots of human teeth were treated endodontically and drilled to a depth of 9mm. Posts were cemented using one of the following three systems (n = 8): group 1 (G1) - Single Bond 2 system (3M ESPE, St. Paul, MN, EUA) / RelyX ARC (3M ESPE, St. Paul, MN, EUA); group 2 (G2) ED Primer (Kuraray Medical Inc. Kurashiki, Japan) / Panavia 21 (Kuraray Medical Inc. Kurashiki, Japan) system; and group 3 (G3) RelyX Unicem (3M ESPE/AG. Seefeld, Germany) cement. The roots were sectioned into three parts corresponding to the coronal, middle and apical thirds. The specimens were submitted to the push-out test. Bond strength values were submitted to analysis of variance (ANOVA) and the Tukey's test (p< 0.05). RESULTS: Only G2 presented statistically significant differences among the three regions of the canal with the apical third presenting the lowest mean bond strength. In relation to the coronal third, G3 presented higher bond strengths than G2. G1 was statistically equal to the other two materials. Regarding the middle and apical thirds, the mean bond strength of G2 was significantly lower than those of G2 and G3, these two being statistically equal. CONCLUSION: The dual-cure cements (RelyX ARC, 3M ESPE, St. Paul, MN, EUA and RelyX Unicem, 3M ESPE, St. Paul, MN, EUA) promoted higher bond strengths between the endodontic post and root dentin than the self-cure cement (Panavia 21, Kuraray Medical Inc., Kurashiki, Japan).