Effects of dentin surface preparations on bonding of self-etching adhesives under simulated pulpal pressure.

Objectives: This study evaluated the effects of different smear layer preparations on the dentin permeability and microtensile bond strength (µTBS) of 2 self-etching adhesives (Clearfil SE Bond [CSE] and Clearfil Tri-S Bond Universal [CTS]) under dynamic pulpal pressure. Materials and Methods: Human third molars were cut into crown segments. The dentin surfaces were prepared using 4 armamentaria: 600-grit SiC paper, coarse diamond burs, superfine diamond burs, and carbide burs. The pulp chamber of each crown segment was connected to a dynamic intra-pulpal pressure simulation apparatus, and the permeability test was done under a pressure of 15 cmH2O. The relative permeability (%P) was evaluated on the smear layer-covered and bonded dentin surfaces. The teeth were bonded to either of the adhesives under pulpal pressure simulation, and cut into sticks after 24 hours water storage for the µTBS test. The resin-dentin interface and nanoleakage observations were performed using a scanning electron microscope. Statistical comparisons were done using analysis of variance and post hoc tests. Results: Only the method of surface preparation had a significant effect on permeability (p < 0.05). The smear layers created by the carbide and superfine diamond burs yielded the lowest permeability. CSE demonstrated a higher µTBS, with these values in the superfine diamond and carbide bur groups being the highest. Microscopic evaluation of the resin-dentin interface revealed nanoleakage in the coarse diamond bur and SiC paper groups for both adhesives. Conclusions: Superfine diamond and carbide burs can be recommended for dentin preparation with the use of 2-step CSE.

Avaliação clínica de restaurações Classe V em cavidades tratadas com o laser de Er: YAG associado ao uso de sistemas adesivos autocondicionantes / Clinical evaluation of Class V restorations in cavities treated with Er: YAG laser associated with the use of self-etching adhesive systems

O objetivo deste estudo clínico, controlado, randomizado, cego e prospectivo foi de avaliar a efetividade clínica de restaurações em lesões não cariosas (cavidades Classe V) realizadas em superfícies dentais pré-tratadas ou não com laser de Er:YAG e utilizando dois sistemas adesivos autocondicionantes. Este estudo foi realizado com um total de 91 lesões e divididas em 4 grupos (n = 23) :G1(FL): Sem pré-tratamento e utilizando o adesiso FL-Bond II/Shofu; G2 (CF): sem pré-tratamento e utilizando o adesivo Clearfil SE Bond 2/Kuraray Noritake; G3 (Laser + FL): pré-tratamento associado ao uso do FL-Bond II/Shofu e G4 (Laser + CF): pré-tratamento associado ao uso do Clearfil SE Bond 2/Kuraray Noritake Os dentes avaliados foram os pré-molares de ambas as arcadas. A avaliação foi feita imediatamente após o tratamento e ao longo do tempo, em 3, 6 e 12 meses após a finalização da restauração. Para a avaliação da sensibilidade foi considerado a EVA (Escala Visual Analógica) e para a qualidade da restauração o método do USPHS modificado, considerando a avaliação de perda de retenção, integridade marginal, pigmentação marginal, presença de lesão de cárie em margem de restauração, vitalidade pulpar e sensibilidade pós-operatória. Os dados foram registrados em tabelas de frequência, e os escores transformados em postos para a aplicação do teste ANOVA. A significância estatística foi considerada para valores de p<0,05. Para os resultados da avaliação de sensibilidade houve uma diferença estatística significante da sensibilidade ao longo do tempo (p<0,001), sendo que essa diferença se deu a partir da avaliação T1 (48 horas) em todos os grupos. Em relação aos critérios avaliados no USPHS, foram encontrados variações estatísticas em alguns tópicos: Pigmentação marginal - G1 (FL) (p=0,041) e G2 ( Laser + FL) (p=0,009) e Integridade marginal G1(FL)( p=0,036). Os demais grupos e critérios não apresentaram variações estatísticas significantes.Pré-tratamentos com laser Er:YAG podem ser uma alternativa viável em restaurações adesivas do tipo classe V; no entanto, nenhum efeito sinérgico de ambos os tratamentos combinados foi observado.

The objective of this clinical, controlled, randomized, blinded and prospective study was to evaluate the clinical effectiveness of restorations in non-carious lesions (Class V cavities) performed on dental surfaces pre-treated or not with Er:YAG laser and using two adhesive systems self-conditioning. This study was carried out with a total of 91 lesions and divided into 4 groups (n = 23) :G1(FL): No pre-treatment and using the FL-Bond II/Shofu adhesive; G2 (CF): without pre-treatment and using Clearfil SE Bond 2/Kuraray Noritake adhesive; G3 (Laser + FL): pre-treatment associated with the use of FL-Bond II/Shofu and G4 (Laser + CF): pre-treatment associated with the use of Clearfil SE Bond 2/Kuraray Noritake The teeth evaluated were the premolars of both arcades. Assessment was performed immediately after treatment and over time, at 3, 6, and 12 months after completion of the restoration. The VAS (Visual Analogue Scale) was used for the sensitivity assessment and the modified USPHS method for the quality of the restoration, considering the assessment of loss of retention, marginal integrity, marginal pigmentation, presence of caries in the restoration margin. , pulp vitality and postoperative sensitivity. Data were recorded in frequency tables, and the scores were transformed into ranks for the application of the ANOVA test. Statistical significance was considered for values of p<0.05. For the results of the sensitivity evaluation, there was a statistically significant difference in sensitivity over time (p<0.001), and this difference occurred from the T1 evaluation (48 hours) in all groups. Regarding the criteria evaluated at the USPHS, statistical variations were found in some topics: Marginal pigmentation - G1 (FL) (p=0.041) and G2 (Laser + FL) (p=0.009) and Marginal integrity - G1(FL)( p =0.036). The other groups and criteria did not present significant statistical variations. Pretreatments with Er:YAG laser can be a viable alternative in class V adhesive restorations; however, no synergistic effect of both treatments combined was observed.

Bonding Performance of Self-etching Adhesives to Bur-cut Dentin with Active Application Mode.

PURPOSE: This study evaluated whether active application of self-etching adhesives would influence their microtensile bond strength (µTBS) to dentin cut with burs of different grit sizes. MATERIALS AND METHODS: Eighty-four human premolars were divided into 12 groups according to 1) two dentin surface preparations with either superfine- or regular-grit diamond burs; 2) three adhesives - Clearfil SE Bond 2 (SE2), Scotchbond Universal (SBU, 3M Oral Care) and G-Premio Bond (GPB, GC); and 3) two application modes of each adhesive (active or passive). Six bonded teeth per group were sectioned into sticks for µTBS testing. Statistical analyses were performed using 3-way ANOVA followed by Duncan's test (p < 0.05). Additional teeth were prepared to observe the interaction between the dentin smear layer obtained from each bur with adhesives under different application modes using transmission electron microscopy (TEM). RESULTS: Active application significantly increased the dentin bond strength of SE2, irrespective of the kind of bur used (p < 0.05). The highest bond strength of SBU was observed when bonded to superfine-grit diamond bur-cut dentin with the active application. There was, however, no influence of the tested factors on GPB group (p > 0.05). TEM observation showed that active application promoted dentin smear layer dissolution in all adhesive groups. CONCLUSIONS: Bond strengths of self-etching adhesives to dentin are influenced by bur-cut smear layers and mainly by application mode of adhesive materials. Active application improves µTBS of self-etching adhesives by enhancing smear layer modification and resin penetration into bur-cut dentin.

Effect of erosive challenge and cigarette smoke on dentin microhardness, surface morphology and bond strength / Efeito de desafios erosivos e fumaça de cigarro na microdureza, morfologia de superfície e resistência de união à dentina

Objective: This study aimed to evaluate the surface microhardness and morphology, as well as the microshear bond strength of a self-etching adhesive (Clearfil SE, Kuraray) to eroded dentin, exposed or not to cigarette smoke. Forty dental crowns were divided into 4 groups (n = 10): no treatment (control) (C); erosion (E); erosion + cigarette smoke exposure (ES); cigarette smoke exposure (S). Samples were prepared through third molars polishing until dentin exposure, followed by crown section. Erosive cycles were performed 5 times/day for 30 s at 60 min intervals. Cigarette smoke was produced with twenty cigarettes/day, during 5 days. Microhardness was evaluated initially and after the treatments. Microshear bond strength was tested after the treatments and dentin restoration with flow composite. Failure patterns and dentin morphology was evaluated by Scanning Electron Microscopy. Microshear bond strength data was submitted to two-way ANOVA, microharness test was adjusted by gamma distribution to be a non-parametric analyses (p=0.05), and surface morphology as qualitative analyses. Loss percentage of microhardness was observed only in groups submitted to erosion. Bond strength was statistically similar between all groups. The most prevalent failure pattern was of adhesive type. Morphological analysis of dentin showed obliterated tubules in groups submitted to cigarette smoke exposure. Cigarette smoke exposure did not promote any effect in the percentage of microhardness loss, as in sound dentin as in eroded dentin. Cigarette smoke, erosion, and association of both, did not alter the bond strength of self-etching adhesives to dentin. (AU)

Objetivo: Este estudo teve como objetivo avaliar a microdureza (% perda de dureza) e morfologia de superfície (MS), assim como a resistência de união (RU) de um adesivo autocondicionante (Clearfil SE, Kuraray) à uma dentina erodida, exposta ou não à fumaça de cigarro. Material e Métodos: Quarenta coroas dentais de terceiros molares foram seccionadas da raiz e polidas até a exposição dentinária, sendo aleatoriamente divididas em 4 grupos (n=10): sem tratamento (controle), erosão (E), erosão+ exposição a fumaça de cigarro (ES); exposição a fumaça de cigarro (S).O ciclo erosivo foi realizado 5 vezes/dia por 30s, com 60 minutos de intervalo entre eles. Os grupos ES e S foram exposto à fumaça de cigarro produzida por 20 cigarros/dia, durante 5 dias. A avaliação da microdureza foi realizada antes e após os tratamentos, enquanto a resistência da união por microcisalhamento foi realizada após os tratamentos Os padrões de fratura representativos e a MS dentinária foram avaliados por microscopia eletrônica de varredura (MEV). Os dados de RU foram analisados por ANOVA dois fatores, enquanto a análise de microdureza foi ajustada por distribuição gama por ser uma análise não-paramétrica (p=0.05). A MS foi analisada qualitativamente. Resultados: Os grupos expostos aos ciclos erosivos (E e ES) apresentaram % de perda de dureza significativamente menor que os grupos não expostos (Controle e S. aos ciclos erosivos (E e ES). Para RU, não houve diferença estatística significativa entre os grupos. O padrão de fratura mais observado foi do tipo adesivo, e através das imagens obtidas por MEV, observou-se a obliteração de túbulos dentinários no grupo exposto à fumaça de cigarro, enquanto os grupos submetidos aos ciclos erosivos (E e ES) apresentaram maior exposição e diâmetro de túbulos dentinários. Conclusão: A exposição à fumaça de cigarro não promove nenhum efeito quanto a perda de porcentagem de dureza dentinária, assim como em dentina erodida e saudável. A fumaça de cigarro, o processo erosivo, e a associação de ambos, não altera a resistência da união de adesivos autocondicionantes à dentina. (AU)

Bond strength of self-etching adhesives to dentin surface after smear layer removal with ultrasonic brushing.

This study determined the micro-shear bond strength (µSBS) of two self-etching adhesives to dentin surface after smear layer removal with a novel ultrasonic brushing method. Ninety-five dentin discs were ground flat with diamond burs and divided into 5 groups; no treatment (control), brushing with a custom-made brush for 10 and 30 s without and with ultrasonic application. The smear layer thickness was evaluated using SEM. The 24 h µSBS of Clearfil SE Bond (CSE) and Clearfil Tri S Bond (CTS) to these dentin surfaces were evaluated. Smear layer thickness decreased significantly from control, brushing without, and brushing with ultrasonic groups, respectively. The µSBS of CSE were higher than CTS in all groups. The µSBS were improved with ultrasonic brushing for 30 s for both adhesives. Ultrasonic brushing is the effective method in mechanical smear layer removal which can improve bond strength of self-etching adhesives to ground dentin.

Influence of self-etch all-in-one adhesives on fissure sealant shear bond strength under contaminated enamel conditions.

AIM: To determine the influence of two all-in-one self-etching adhesive systems on shear bond strength of a fissure sealant applied under different enamel surface conditions. METHODS: A total of 180 bovine enamel specimens were randomly distributed to nine experimental groups, defined by the combination of the sealant application technique (using phosphoric acid, or a self-etching water-based adhesive or a self-etching ethanol and water-based adhesive) and enamel surface conditions (dry enamel, saliva or water contaminated enamel). The specimens were submitted to thermocycling prior to the shear bond strength test. RESULTS: High shear bond strength mean values were obtained with the classic technique for dry enamel (31.47 MPa), statistically similar values were obtained when the sealant was combined with a self-etching water-based adhesive, in dry enamel (32.36 MPa), and when the sealant was combined with a self-etching water-based adhesive in water contaminated enamel (32.62 MPa). Under enamel salivary contamination, the best results were achieved using a water-based adhesive (24.78 MPa). CONCLUSIONS: In saliva contaminated enamel, the combination of a sealant with a water-based self-etching adhesive can maintain high and satisfactory values of bond strength.

Effect of smear layer and surface roughness on resin-dentin bond strength of self-etching adhesives.

The purpose of this study was to evaluate the effect of surface roughness and smear layer on the micro-shear bond strength (µSBS) of two self-etching adhesives, Clearfil SE Bond (SE) and Clearfil Tri-S Bond (S3). Flat dentin surfaces were prepared with SiC papers (600-, 180- and 120-grit) and diamond burs (extra fine, medium and coarse). They were further divided into smear-covered and smear-free surfaces and bonded with respective adhesives. µSBS test was performed after water storage at 37ºC for 24 h. Smear layer thickness measurement was evaluated by scanning electron microscope (SEM). Surface roughness was examined by contact stylus profilometer. Smear layer thickness and surface roughness were significantly different among all groups (p<0.05). No difference in µSBS was observed among surface prepared by SiC whereas bur-cut smear layer had negative effect on µSBS, especially for S3. Surface roughness from different surface preparations had no influence on µSBS (p<0.05).

Evaluation of sealing ability two self-etching adhesive systems and a glass ionomer lining LC under composite restoration in primary tooth: An in vitro study.

AIMS AND OBJECTIVES: To evaluate the sealing ability of two self-etching adhesive systems and glass ionomer cement (GIC) lining Light cure (LC) under composite restorations in primary teeth. MATERIALS AND METHODS: Class V cavities are prepared on the cervical third of the facial and lingual surfaces of primary molars. The specimens are then assigned into four experimental groups. The restored primary molars are stored in distilled water and subjected to thermocycling. Each section was examined using a stereomicroscope to assess dye penetration at the margin of the restoration and evaluated via pictures. STATISTICAL ANALYSIS USED: The degree of microleakage was analyzed using Kruskal-Wallis test and the intergroup significance by multiple comparison analysis. RESULTS: The mean rank of the groups are Group I (Adper Prompt™ + Z-100) 19.44, Group II (UniFil BOND + Solare) 5.38, Group III (GIC lining LC + Z-100) 20.06, and Group IV (GIC lining LC + Solare) 21.13 with the P < 0.001. CONCLUSION: Composite resin restorations bonded with two-step self-etching adhesive system (UniFil Bond) exhibited lesser microleakage than one-step self-etching adhesive system (Adperprompt™) in primary teeth.

Comparison of Shear Bond Strength of Three Self-etching Adhesives: An In-Vitro Study.

BACKGROUND: The aim of the study was to determine and compare the shear bond strength of brackets bonded with Adper Promt self-etching adhesive (3M ESPE), Xeno III self-etching adhesive (DENSPLY), Transbond plus self-etching adhesive (3M) with that of conversional bonding procedure, and to calculate the adhesive remnant index (ARI). MATERIALS AND METHODS: Totally, 60 maxillary premolar teeth were collected, and divided into Group I (Blue): Transbond™ XT primer, Group II (Purple): Adper™ Prompt™ self-etching adhesive, Group III (Orange): Xeno III® self-etching adhesive, Group IV (Pink): Tranbond™ Plus self-etching adhesive. RESULTS: The results of the study showed there was no statistical significance in the shear bond strength according to an analysis of variance (P = 0.207) of the four groups. The mean shear bond strength of Groups I, II, III, IV were 14.56 ± 2.97 Megapascals (MPa), 12.62 ± 2.48 MPa, 13.27 ± 3.16, and 12.64 ± 2.56, respectively. Chi-square comparison for the ARI indicated that there was a significant difference (P = 0.003) between the groups. CONCLUSION: All the four self-etching adhesives showed clinically acceptable mean shear bond strength. The ARI score showed a self-etching adhesive the debonding occurred more within the adhesive interface leaving less composite adhesive on the tooth surface making it easy to clean up.

Carious affected dentine: its behaviour in adhesive bonding.

BACKGROUND: Carious affected dentine (CAD) represents a very common substrate in adhesive dentistry. Despite its ability to interact with adhesive systems, the intrinsic character of CAD leads to lower bonding compared with sound dentine, regardless of the adhesive systems used. This low bonding may be more susceptible to leakage and hydrolysis of the interface by matrix metalloproteinases (MMPs). This systematic review aimed to determine current knowledge of CAD bonding, together with bond strength and MMP inhibitors' ability to prevent hybrid layer instability. METHODS: MEDLINE/Pubmed, Scopus and The Cochrane Library databases were electronically searched for articles published from 1 January 1960 to 31 August 2014. Two reviewers independently screened and included papers according to predefined selection criteria. RESULTS: The electronic searches identified 320 studies. After title, abstract and full-text examinations, 139 articles met the inclusion criteria. Data highlighted that a poor resin saturation of the already demineralized collagen matrix in CAD is strictly related to nanoleakage in interdiffusion and is the basis of the progressive decrease in strength with hydrolysis by MMPs. The use of mild self-etching systems seems to be the more accredited method to establish bonding in CAD. Inhibitors of MMPs may ensure better performance of CAD bonding, allowing undisturbed remineralization of the affected matrix. CONCLUSIONS: CAD bonding needs further understanding and improvement, particularly to enhance the strength and durability of the hybrid layer.

The role of spacer carbon chain in acidic functional monomers on the physicochemical properties of self-etch dental adhesives.

OBJECTIVES: To evaluate the effects of acidic functional monomers with different hydrophilicity and spacer carbon chain length on the degree of conversion (DC), wettability (contact angle), water sorption (WS) and ultimate tensile strength (UTS) of experimental one-step self-etch adhesives (1-SEAs). METHODS: A series of standard resin blends was prepared with each formulation containing 15mol% of each acidic monomer. The structural variations of the acidic monomers were MEP (spacer chain with 2 carbons), MDP (10-carbons), MDDP (12-carbons), MTEP (more hydrophilic polyether spacer) and CAP-P (intermediate hydrophilicity ester spacer). Dumbbell-shaped and disc specimens were prepared and tested for UTS and WS, respectively. DC was assessed by FTIR, while the wettability of each 1-SEA was evaluated on glass slides and flat dentine surfaces. Results were analysed with one-way ANOVA and Tukey's test (p<0.05). RESULTS: The outcomes showed lower UTS for CAP-P, control blend and MEP than MTEP, MDDP and MDP (p<0.05). The degree of conversion was statistically similar for all resins (p=0.122). On dentine, the wettability was higher (lower contact angle) with the most hydrophilic monomer MTEP. Higher WS was attained using MTEP. Different lengths of the spacer chains did not result in different wettability and WS (p>0.05). CONCLUSION: At similar molar percentage, different acidic functional monomers induced similar degree of conversion and different UTS when included in a 1-SEA. However, the inclusion of highly hydrophilic monomer may increase the wettability on dentine and the WS.

Fluid flow through dentin-self-etch resin interface during long term in vitro aging.

This work aimed at characterizing the interface between dentin and the resin-infiltrated dentin made following the etching procedure that prepares for the bonding of tooth-colored restorations. The non-destructive measurement of fluid flow through the dentin-self-etch resin interface was followed repeatedly during a two year aging period. Two self-etch adhesive systems were selected for experiments on the evolution of permeability and evaluation of infrared spectral changes following the 24 month aging period. The adhesives contained water and a co-solvent, namely acetone for iBond, and t-butanol for Xeno V. For both adhesive systems, the permeability decreased during the first 3 months after etching, reaching values of -66.9 and -70.5% for iBond and Xeno V, respectively. Afterwards, the fluid flow slowly increased but still remained below 50% of the initial value following the 2-year aging period. The slow degradation of the resin-dentin interface, attributed to water impregnated collagen hydrolysis, is evidenced by these variations in fluid flow, and is also noted by the increase in water-related infrared absorption bands at 3300 cm(-1) and at 1600 cm(-1). The results are discussed in terms of co-solvent hydrophobicity, evaporation rate and viscosity together with resin infiltration depth and affinity for water.

Effect of chlorhexidine cavity disinfection on microleakage in cavities restored with composite using a self-etching single bottle adhesive.

AIMS: This study evaluated the effect of 2% chlorhexidine cavity disinfectant on microleakage in class II cavities restored with light cured composites using a single bottle adhesive in an in vitro model. MATERIALS AND METHODS: Proximal box cavities were prepared on mesial and distal surfaces of 40 non carious mandibular third molars, resulting in total of 80 cavities. Forty cavities on were rinsed with normal saline and 40 cavities were rinsed with 2% chlorhexidine cavity disinfectant. All cavities were restored with a single bottle adhesive and nano hybrid composite resin. Microleakage was evaluated at the gingival margin using methylene blue dye penetration method. RESULTS AND CONCLUSION: Chlorhexidine cavity disinfectants produced significantly higher microleakage while restoring the cavities using a self-etching single bottle adhesive.

Aspectos importantes na escolha dos adesivos autocondicionantes / Important aspects in the choice of autocondicionantes adhesives

Desde os trabalhos de Buonocore, a adesão resinosa à estrutura dentária trouxe mudanças importantes para a prática odontológica, desenvolvendo alternativas de tratamento restaurador, com preparo cavitário mais conservador, maior preservação de esmalte/dentina sadios e melhoria no aspecto estéticodas restaurações. Na atualidade, os adesivos autocondicionantes, que excluem a etapa do condicionamento ácido prévio, apresentam um aumento na sua popularidade de uso. Este artigo tem o objetivo de revisar a literatura sobre os adesivos autocondicionantes, avaliando aspectos sobre sua composição e mecanismo de ação.

Since the study of Buonocore, resinous adhesion to dental structure brought important changes fordentistry practical, developing alternative of restoring treatment with preparation of cavity more conservative,greater healthy enamel /dentine preservation and improvement in the aesthetic aspect of therestorations. In the present time, the self-etching adhesives which exclude the stage of previous the acidconditioning, present an increase in its popularity of use. This article has the purpose to revise literature onself-etching adhesives, evaluating aspects on its composition and mechanism of action.

The effects of total-etch, wet-bonding, and light-curing of adhesive on the apical seal of a resin-based root canal filling system / 대한치과보존학회지

OBJECTIVES: This study evaluated the effects of adhesion variables such as the priming concepts of canal wall and the curing modes of adhesives on the sealing ability of a resin-based root canal filling system. MATERIALS AND METHODS: Apical microleakage of the Resilon-RealSeal systems filled with 3 different combinations of adhesion variables was compared with the conventional gutta-percha filling using a dye penetration method. Experimental groups were SEDC, Resilon (Resilon Research LLC) filling with self-etch RealSeal (SybronEndo) primer and dual-cure RealSeal sealer; NELC, Resilon filling with no etching, Scotchbond Multi-Purpose (3M ESPE) primer application and light-curing adhesive; and TELC, Resilon filling with Scotchbond Multi-Purpose primer and adhesive used under total etch / wet bonding and light-cure protocols. GPCS, gutta-percha filling with conventional AH26 plus sealer, was the control group. RESULTS: The median longitudinal dye penetration length of TELC was significantly shorter than those of GPCS and SEDC (Kruskal-Wallis test, p < 0.05). In the cross-sectional microleakage scores, TELC showed significant differences from other groups at 2 to 5 mm from the apical foramen (Kruskal-Wallis test, p < 0.05). CONCLUSIONS: When a resin-based root canal filling material was used, compared to the self-etching primer and the dual-cure sealer, the total etch/wet-bonding with primer and light-curing of adhesive showed improved apical sealing and was highly recommended.

Influence of application methods of one-step self-etching adhesives on microtensile bond strength / 대한치과보존학회지

OBJECTIVES: The purpose of this study was to evaluate the effect of various application methods of one-step self-etch adhesives to microtensile resin-dentin bond strength. MATERIALS AND METHODS: Thirty-six extracted human molars were used. The teeth were assigned randomly to twelve groups (n = 15), according to the three different adhesive systems (Clearfil Tri-S Bond, Adper Prompt L-Pop, G-Bond) and application methods. The adhesive systems were applied on the dentin as follows: 1) The single coating, 2) The double coating, 3) Manual agitation, 4) Ultrasonic agitation. Following the adhesive application, light-cure composite resin was constructed. The restored teeth were stored in distilled water at room temperature for 24 hours, and prepared 15 specimens per groups. Then microtensile bond strength was measured and the failure mode was examined. RESULTS: Manual agitation and ultrasonic agitation of adhesive significantly increased the microtensile bond strength than single coating and double coating did. Double coating of adhesive significantly increased the microtensile bond strength than single coating did and there was no significant difference between the manual agitation and ultrasonic agitation group. There was significant difference in microtensile bonding strength among all adhesives and Clearfil Tri-S Bond showed the highest bond strength. CONCLUSIONS: In one-step self-etching adhesives, there was significant difference according to application methods and type of adhesives. No matter of the material, the manual or ultrasonic agitation of the adhesive showed significantly higher microtensile bond strength.

Reflections about adhesive systems / Reflexiones acerca de los sistemas adhesivos

The adhesive systems are responsible for an efficient union between teeth and resin, resulting in a longevity restoration. They are organic molecules di or multifunctional that contain reactive groups that interact with dentin and with the resin monomer of composite resin. The adhesive systems are characterized by wet adhesion, which is a result of presence of hidrophylics radicals in their compositions, to promote a better bond and the best properties of the adhesion. Adhesive systems may use two different strategies to interact with the dental structure: total-etching and self-etching technique. The total-etching systems require a conditioning, a rinsing and a priming step in order to allow involvement of collagen fibers by the resin monomers and the formation of the so-called ‘hybrid layer’. The total-etching promotes the cleaning of dentin, also promotes superficial demineralization and delivers collagen fibrils to participate of an interface union mechanism teeth/ adhesive system/restorative material. Self-etching adhesive systems are characterized by demineralization and infiltration of resin monomers simultaneously. This technique is attractive because reduced sensitivity associated with retaining the smear layer and smear plugs, thereby, minimize the possibility of inadvertent contamination of the bonding surface with dentinal surface through dentinal fluid transudate.

Los sistemas adhesivos son responsables de una unión eficaz entre los dientes y la resina, dando como resultado una restauración durable. Son moléculas orgánicas bi o multifuncionales que contienen grupos reactivos que interactúan con la dentina y con el monómero de resina de composite. Los sistemas adhesivos se caracterizan por la adhesión húmeda, que es el resultado de la presencia de radicales hidrofílicos en sus composiciones, para promover una mejor adherencia y las mejores propiedades de la adhesión. Los sistemas adhesivos pueden utilizar dos estrategias diferentes para interactuar con la estructura dental: Técnica de grabado total y auto-grabado. Los sistemas de grabado total requiere un acondicionamiento, un lavado y un paso de priming con el fin de permitir la participación de las fibras de colágeno por los monómeros de resina y la formación de la llamada capa híbrida. El grabado total promueve la limpieza de la dentina, también promueve la desmineralización superficial y condiciona a las fibrillas de colágeno para participar de un mecanismo de interfaz de unión diente/sistema adhesivo /material de restauración. Los sistemas adhesivos autograbantes se caracterizan por la desmineralización y la infiltración de los monómeros de resina de forma simultánea. Esta técnica es atractiva debido a la sensibilidad reducida asociada a conservar la capa de barro dentinario y tapones de barro dentinario, reduciendo al mínimo la posibilidad de contaminación accidental de la superficie de unión con la superficie de la dentina a través del líquido dentinario trasudado.

Bond Strength of One-Step Adhesives under Different Substrate Moisture Conditions.

OBJECTIVES: The aim of this study was to evaluate the bond strength of one-step adhesive systems to dry or moist dental substrate. METHODS: Thirty human third molars were sectioned into two halves, in the mesio-distal direction, parallel to the long axis of the tooth. Each half was embedded in a polystyrene resin cylinder so that the buccal/lingual surface remained exposed. This exposed surface was abraded to obtain both flat exposed enamel and dentin. The samples were randomly allocated according to the adhesive system (Xeno III, Adper Prompt and iBond) and moisture condition (dry and moist). The substrates were air-dried for 30 s for dry condition, while the moist substrates were re-wet with 2.5 mul of distilled water after drying. After the adhesive procedures, two resin composite cylinders were build-up on dentin and enamel substrates, totaling four per sample. A shear load was applied to the samples at a crosshead speed of 0.5 mm/min until failure. Data were statistically analyzed by three-way ANOVA and the Tukey test (alpha=0.05). RESULTS: The evaluated one-step adhesives showed higher bond strength to dentin than enamel. The iBond presented better bond performance to moist substrate and Xeno III to dry substrate. The moisture condition did not interfere in the performance of Adper Prompt. The Xeno III and iBond presented higher bond strength than the other adhesives to both dry and moist substrates. CONCLUSIONS: The moisture condition of substrate interfered in the performance of one-step self-etching adhesives and the best moisture condition was material dependent.

Bond strength durability of self-etching adhesives and resin cements to dentin

OBJECTIVES: To evaluate the microtensile bond strength (µTBS) of one- (Xeno III, Dentsply) and two-step (Tyrian-One Step Plus, Bisco) self-etching adhesive systems bonded to dentin and cemented to chemically cured (C&B Metabond) or light-cured paste of a dual-cure resin cement (Variolink II, Ivoclar) within a short (24 h) and long period of evaluation (90 days). MATERIAL AND METHODS: Forty recently extracted human molars had their roots removed and their occlusal dentin exposed and ground wet with 600-grit SiC paper. After application of one of the adhesives, the resin cement was applied to the bonded surface and a composite resin block was incrementally built up to a height of 5 mm (n=10). The restored teeth were stored in distilled water at 37ºC for 7 days. The teeth were then cut along two axes (x and y), producing beam-shaped specimens with 0.8 mm² cross-sectional area, which were subjected to µTBS testing at a crosshead speed of 0.05 mm/min and stressed to failure after 24 h or 90 days of storage in water. The µTBS data in MPa were subjected to three-way analysis of variance and Tukey's test (α= 0.05). RESULTS: The interaction effect for all three factors was statistically significant (three-way ANOVA, p<0.001). All eight experimental means (MPa) were compared by the Tukey's test (p<0.05) and the following results were obtained: Tyrian-One Step Plus /C&B/24 h (22.4±7.3); Tyrian-One Step Plus /Variolink II/24 h (39.4±11.6); Xeno III/C&B/24 h (40.3±12.9); Xeno III/Variolink II/24 h (25.8±10.5); Tyrian-One Step Plus /C&B/90 d (22.1±12.8) Tyrian-One Step Plus/VariolinkII/90 d (24.2±14.2); Xeno III/C&B/90 d (27.0±13.5); Xeno III/Variolink II/90 d (33.0±8.9). CONCLUSIONS: Xeno III/Variolink II was the luting agent/adhesive combination that provided the most promising bond strength after 90 days of storage in water.

Influence of human and bovine substrate on the microleakage of two adhesive systems

The aim of this study was to evaluate in vitro the marginal sealing of two adhesive systems and to analyze the influence of human and bovine substrates on marginal microleakage in enamel. Rectangular-shaped class V cavities (4 mm wide x 2 mm high x 2 mm deep) were made as follows: 8 cavities were prepared on the buccal and lingual surfaces of the human teeth with margins located on enamel and 16 cavities were prepared on the buccal surfaces of the bovine teeth. The cavities were randomly assigned to 4 groups of 8 cavities according to the adhesive system and substrate: G1 - Prime & Bond 2.1 (Dentsply)/human substrate; G2 - Adhese (Ivoclar/Vivadent)/human substrate; G3 - Prime & Bond 2.1 (Dentsply)/bovine substrate; G4 - Adhese (Ivoclar/Vivadent)/bovine substrate. The cavities were filled with microhybrid composite resin (Fillmagic) and after polishing/finishing procedures, the teeth were subjected to a thermocycling regimen of 500 cycles with 1-min immersions in water at 55° ±2°C and 5° ± 2°C. Next, the teeth were coated with two layers of nail polish to within 1 mm of the margin, submerged in a 50 percent silver nitrate solution for 2 h, rinsed thoroughly in running tap and immersed in developing solution for 8 h. The restorations were bisected resulting in 16 specimens. Microleakage was observed under a stereomicroscope at x25 and recorded using four-point (0-3) scoring system. The data were analyzed statistically by the Mann Whitney U-test at 5 percent significance level. Leakage was present in all specimens and there was statistically significant difference between the adhesive systems. Adhese self-etching system showed significantly more leakage in both substrates (human - p= 0.0001 and bovine - p= 0.0031). There was no statistically significant difference between human and bovine substrates for either of the adhesive systems based on different bonding mechanisms (Prime & Bond 2.1 - p= 0.6923 and Adhese - p= 0.6109). Neither of the...