Effect of Nisin-based pretreatment solution on dentin bond strength, antibacterial property, and MMP activity of the adhesive interface.

OBJECTIVE: To evaluate the effect of a Nisin-based dentin pretreatment solution on microtensile bond strength, antibacterial activity, and matrix metalloproteinase (MMP) activity of the adhesive interface. MATERIALS AND METHODS: 100 human molars were sectioned to expose dentin. The teeth were assigned to five groups (n = 20), according to the dentin pretreatment: 0.5%, 1.0%, or 1.5% Nisin; 0.12% chlorhexidine (positive control), and no solution (negative control), and divided into 2 subgroups: no aging, and thermomechanical aging. Specimens were etched with 37% H3PO4 for 15 s and submitted to the dentin pretreatment. Then, they were bonded with an adhesive (Adper Single Bond 2) and a resin composite for microtensile bond strength (µTBS) evaluation. Antibacterial activity against Streptococcus mutans was qualitatively examined using an agar diffusion test. Anti-MMP activity within hybrid layers was examined using in-situ zymography. Data were analyzed with two-factor ANOVA and post-hoc Tukey's test (α = 0.050). RESULTS: For µTBS, significant differences were identified for the factors "solutions" (p = 0.002), "aging" (p = 0.017), and interaction of the two factors (p = 0.002). In the absence of aging, higher µTBS was observed for the group 0.5% Nisin. In the presence of aging, all groups showed similar µTBS values. All Nisin concentrations were effective in inhibiting the growth of S. mutans. Endogenous MMP activity was more significantly inhibited using 0.5% and 1.0% Nisin (p < 0.050). CONCLUSION: 0.5% and 1.0% Nisin solutions do not adversely affect resin-dentin bond strength and exhibit a potential bactericidal effect against S. mutans. Both concentrations effectively reduce endogenous gelatinolytic activity within the hybrid layer. CLINICAL RELEVANCE: The use of 0.5% and 1.0% Nisin solutions for dentin pretreatment potentially contributes to preserving the adhesive interface, increasing the longevity of composite restorations.

Influence of chlorhexidine, propolis, pulpal pressure simulation, and aging on dentin bond strength.

The present study evaluated the bond strength (µTBS) of dentin treated with chlorhexidine and propolis subjected to simulated pulpal pressure (SPP) and thermocycle aging. One hundred and twenty healthy human molars were sectioned to obtain 2 mm of dentin thickness and were divided into two groups (n = 60): SPP (15 cm H2 O) and no SPP (Control group). Dentin surfaces were conditioned with 37% phosphoric acid for 15 s and were divided according to the dentin treatment (n = 20): Control; Chlorhexidine gluconate (0.2% for 30 s) and Propolis (aqueous propolis extract for 30 s). Half of the specimens were submitted to 15,000 thermocycle aging (5 ± 2°C and 55 ± 2°C). The samples were sectioned into beams and submitted to µTBS. Data were analyzed by three-way ANOVA (SPP × Dentin treatment × Thermocycle aging) and the Tukey's tests (p < .001). With regard to the SPP, ANOVA revealed that the Control group (32.98 MPa) had significantly higher values of µTBS when compared to the SPP (29.19 MPa). With regard to Thermocycle aging, no aging (34.05 MPa) had significantly higher values of µTBS when compared to the aging (28.12 MPa). With regard to the dentin treatment, Propolis and Chlorhexidine did not statistically influence the results (p > .05). The SPP and thermocycle aging negatively influenced the bond strength between the dentin and resin; the 0.2% chlorhexidine digluconate and aqueous propolis extract solutions did not interfere in the bond strength between the resin and dentin. The use of chlorhexidine and propolis as a dental treatment may not influence the dentin bond strength, but SPP and thermocycle aging may damage the longitudinal dentin bond strength. RESEARCH HIGHLIGHTS: Chlorhexidine and propolis as a dental treatment may not influence the dentin bond strength. Simulated pulpal pressure and thermocycle aging may damage the longitudinal dentin bond strength.

Computer Aided Design Modelling and Finite Element Analysis of Premolar Proximal Cavities Restored with Resin Composites.

This study evaluated the stress distribution in five different class II cavities of premolar models restored with conventional or bulk-fill flowable composite by means of finite element analysis (FEA) under shrinkage and occlusal loading. An upper validated premolar model was imported in the software, and five class II cavities with different occlusal extensions and dimensions were prepared: horizontal cavity on the mesial surface (horizontal slot), mesio-occlusal cavity, mesial cavity (vertical slot), tunnel type cavity and direct access cavity. The models were restored with conventional or bulk-fill flowable resin composite. The tested materials were considered as homogeneous, linear, and isotropic. The Maximum Principal Stress criteria was chosen to evaluate the tensile stress results. The lowest shrinkage stress value was observed in the direct access cavity restored with bulk-fill flowable resin composite (36.12 MPa). The same cavity, restored with conventional composite showed a score of 36.14 MPa. The horizontal slot cavity with bulk-fill flowable showed a score of 46.71 MPa. The mesio-occlusal cavity with bulk-fill flowable had a score of 53.10 MPa, while with conventional composite this was 55.35 MPa. Higher shrinkage stress was found in the vertical slot cavity with conventional resin 56.14 MPa, followed by the same cavity with bulk-fill flowable 56.08 MPa. Results indicated that the use of bulk-fill flowable composite resin more significantly decreased the polymerization shrinkage stress magnitude. The larger the cavity and the volume of material necessary to restore the tooth, the greater the residual stress on enamel and dentin tissue.

Minimal intervention in dentistry: which is the best approach for silorane composite restoration repairs?

BACKGROUND: This study aimed to evaluate surface treatments, adhesives and composites for repairing silorane based restorations. MATERIAL AND METHODS: One hundred and twenty truncated cones (2 mm smaller diameter and 4 mm larger diameter) made of silorane composite were divided in 12 groups according with the surface treatment (diamond bur and oxide aluminum abrasion), the adhesive (Adper Scothbond Multipurpose (3M ESPE), Ecusit (Voco) and Filtek P90 Adhesive (3M ESPE)). Each group was subdivided in two according with the composite used for repair (methacrylate and silorane). The repair was made with a second truncated cone build over the first one and bond strength assssed by tensile strength. Data were submitted to ANOVA 3-way and Tukey's test (p<0.05). RESULTS: There was difference only for the adhesives and the composites, with conventional adhesives (Adper Scothbond Mutipurpose) and methacrylate-based composites (Filtek Z350) presenting superior tensile strength compared to the silorane ones (P90 Adhesive system and composite). CONCLUSIONS: Therefore, it must be concluded that silorane composite can be repaired with methacrylate base composites and adhesives. Key words:Silorane composites, composites, bond strength, minimal intervention.

Avaliação das propriedades de um sistema adesivo modificado por partículas de vidro bioativas / Evaluation of the properties of an adhesive system modified by bioactive glass particles

O objetivo desse estudo foi avaliar as propriedades de um sistema adesivo modificado com a incorporação de partículas de vidro bioativas (SCHOTT Bioactive Glass) em duas diferentes concentrações (0,5 e 1%). Foram avaliados a resistência de união da interface adesiva, o grau de conversão e a atividade antibacteriana, além da análise por meio do Estereomicroscópio e Microscópio Eletrônico de Varredura (MEV). Os adesivos foram divididos em três grupos: ASB - Adesivo Single Bond 2 (3M-ESPE) sem a incorporação de partículas bioativas, ASB0,5 ­ Adesivo Single Bond 2 com a incorporação de partículas bioativas na concentração de 0,5% e ASB1 ­ Adesivo Single Bond 2 com a incorporação de partículas bioativas na concentração de 1%. Para o teste de resistência de união foram utilizados 30 molares humanos hígidos (n=10) que posteriormente foram observados em Estereomicroscópio para análise do padrão da fratura. O grau de conversão foi feito no FTIR, onde foram feitas três leituras das gotas do adesivo dos diferentes grupos. A atividade antibacteriana foi feita através dos testes de difusão em ágar e contagem da unidade formadora de colônia (UFC), onde foram utilizados discos de adesivos polimerizados dos diferentes grupos. Os testes antibacterianos foram repetidos por três vezes. Os dados foram analisados estatisticamente quanto à sua normalidade. Como estes apresentaram distribuição normal, realizou-se o teste de análise de variância (ANOVA) paramétrica um fator (sistema adesivo) e o teste de Tukey, sendo adotado o nível de significância de 5% para a tomada de decisões. De acordo com os resultados obtidos na microtração (MPa±Dp) , a maior média foi observada no grupo ASB0,5 49,04±4,72A, seguida do grupo ASB 41,19±2,34B e a menor média foi observada no grupo ASB1 27,15±2,36C. No grau de conversão a maior média foi observada no grupo ASB 77,75±2,97A, seguido do grupo ASB0,5 63,18 ± 20,03A e grupo ASB1 58,35 ± 14,95A. Na atividade antibacteriana não houve diferença na formação de áreas de inibição, entretanto na unidade formadora de colônia o grupo ASB0,5 0,36±0,02B apresentou menor média em relação aos grupos ASB1 0,53±0,06A e ASB 0,51±0,01A. Foi concluído que a incorporação de partículas de vidro bioativas na concentração de 0,5% no sistema adesivo, aumentou a resistência de união da interface adesiva e apresentou atividade antibacteriana (UFC), no entanto, nas diferentes concentrações, não influenciou no grau de conversão do adesivo(AU)

The objective of this study was to evaluate the properties of a modified adhesive system with the incorporation of bioactive glass particles (SCHOTT Bioactive Glass) in two different concentrations (0.5 and 1%). The bond strength of the adhesive interface, the degree of conversion and antibacterial activity were evaluated, in addition to analysis using the Stereomicroscope and Scanning Electron Microscope (SEM). The adhesives were divided into three groups: ASB - Single Bond 2 Adhesive (3MESPE) without the incorporation of bioactive particles, ASB0.5 - Single Bond 2 Adhesive with the incorporation of bioactive particles at a concentration of 0.5% and ASB1 - Single Bond 2 adhesive with the incorporation of bioactive particles at a concentration of 1%. For the microtensile bond strength test, 30 healthy human molars (n = 10) were used, which were subsequently observed in a stereomicroscope to analyze the fracture pattern. The degree of conversion was made in the FTIR, where three readings of the drops of the adhesive of the different groups were made. The antibacterial activity was performed through the agar diffusion tests and colony forming unit (CFU) counting, where polymerized adhesive discs from different groups were used. The antibacterial tests were repeated three times. The data were analyzed statistically for normality. As these showed normal distribution, the parametric one-way analysis of variance (ANOVA) test (adhesive system) and the Tukey test were performed, with a significance level of 5% for decision making. According to the results obtained in microtensile (MPa ± Dp), the highest average was observed in the ASB0.5 group 49.04 ± 4.72A, followed by the ASB group 41.19 ± 2.34B and the lowest average was observed in the ASB1 group 27.15 ± 2.36C. In the degree of conversion, the highest average was observed in the ASB group 77.75 ± 2.97A, followed by the ASB0.5 group 63.18 ± 20.03A and ASB1 group 58.35 ± 14.95A. In the antibacterial activity there was no difference in the formation of areas of inhibition, however in the colony-forming unit the ASB0.5 group 0.36 ± 0.02B presented a lower average in relation to the ASB1 groups 0.53 ± 0.06A and ASB 0.51 ± 0.01A. It was concluded that the incorporation of bioactive glass particles at a concentration of 0.5% in the adhesive system, increased the bond strength of the adhesive interface and showed antibacterial activity (CFU), however, in different concentrations, did not influence the degree of conversion of the adhesive(AU)

Avaliação das propriedades de um sistema adesivo modificado por partículas de vidro bioativas / Evaluation of the properties of an adhesive system modified by bioactive glass particles

O objetivo desse estudo foi avaliar as propriedades de um sistema adesivo modificado com a incorporação de partículas de vidro bioativas (SCHOTT Bioactive Glass) em duas diferentes concentrações (0,5 e 1%). Foram avaliados a resistência de união da interface adesiva, o grau de conversão e a atividade antibacteriana, além da análise por meio do Estereomicroscópio e Microscópio Eletrônico de Varredura (MEV). Os adesivos foram divididos em três grupos: ASB - Adesivo Single Bond 2 (3M-ESPE) sem a incorporação de partículas bioativas, ASB0,5 ­ Adesivo Single Bond 2 com a incorporação de partículas bioativas na concentração de 0,5% e ASB1 ­ Adesivo Single Bond 2 com a incorporação de partículas bioativas na concentração de 1%. Para o teste de resistência de união foram utilizados 30 molares humanos hígidos (n=10) que posteriormente foram observados em Estereomicroscópio para análise do padrão da fratura. O grau de conversão foi feito no FTIR, onde foram feitas três leituras das gotas do adesivo dos diferentes grupos. A atividade antibacteriana foi feita através dos testes de difusão em ágar e contagem da unidade formadora de colônia (UFC), onde foram utilizados discos de adesivos polimerizados dos diferentes grupos. Os testes antibacterianos foram repetidos por três vezes. Os dados foram analisados estatisticamente quanto à sua normalidade. Como estes apresentaram distribuição normal, realizou-se o teste de análise de variância (ANOVA) paramétrica um fator (sistema adesivo) e o teste de Tukey, sendo adotado o nível de significância de 5% para a tomada de decisões. De acordo com os resultados obtidos na microtração (MPa±Dp) , a maior média foi observada no grupo ASB0,5 49,04±4,72A, seguida do grupo ASB 41,19±2,34B e a menor média foi observada no grupo ASB1 27,15±2,36C. No grau de conversão a maior média foi observada no grupo ASB 77,75±2,97A, seguido do grupo ASB0,5 63,18 ± 20,03A e grupo ASB1 58,35 ± 14,95A. Na atividade antibacteriana não houve diferença na formação de áreas de inibição, entretanto na unidade formadora de colônia o grupo ASB0,5 0,36±0,02B apresentou menor média em relação aos grupos ASB1 0,53±0,06A e ASB 0,51±0,01A. Foi concluído que a incorporação de partículas de vidro bioativas na concentração de 0,5% no sistema adesivo, aumentou a resistência de união da interface adesiva e apresentou atividade antibacteriana (UFC), no entanto, nas diferentes concentrações, não influenciou no grau de conversão do adesivo (AU)

The objective of this study was to evaluate the properties of a modified adhesive system with the incorporation of bioactive glass particles (SCHOTT Bioactive Glass) in two different concentrations (0.5 and 1%). The bond strength of the adhesive interface, the degree of conversion and antibacterial activity were evaluated, in addition to analysis using the Stereomicroscope and Scanning Electron Microscope (SEM). The adhesives were divided into three groups: ASB - Single Bond 2 Adhesive (3MESPE) without the incorporation of bioactive particles, ASB0.5 - Single Bond 2 Adhesive with the incorporation of bioactive particles at a concentration of 0.5% and ASB1 - Single Bond 2 adhesive with the incorporation of bioactive particles at a concentration of 1%. For the microtensile bond strength test, 30 healthy human molars (n = 10) were used, which were subsequently observed in a stereomicroscope to analyze the fracture pattern. The degree of conversion was made in the FTIR, where three readings of the drops of the adhesive of the different groups were made. The antibacterial activity was performed through the agar diffusion tests and colony forming unit (CFU) counting, where polymerized adhesive discs from different groups were used. The antibacterial tests were repeated three times. The data were analyzed statistically for normality. As these showed normal distribution, the parametric one-way analysis of variance (ANOVA) test (adhesive system) and the Tukey test were performed, with a significance level of 5% for decision making. According to the results obtained in microtensile (MPa ± Dp), the highest average was observed in the ASB0.5 group 49.04 ± 4.72A, followed by the ASB group 41.19 ± 2.34B and the lowest average was observed in the ASB1 group 27.15 ± 2.36C. In the degree of conversion, the highest average was observed in the ASB group 77.75 ± 2.97A, followed by the ASB0.5 group 63.18 ± 20.03A and ASB1 group 58.35 ± 14.95A. In the antibacterial activity there was no difference in the formation of areas of inhibition, however in the colony-forming unit the ASB0.5 group 0.36 ± 0.02B presented a lower average in relation to the ASB1 groups 0.53 ± 0.06A and ASB 0.51 ± 0.01A. It was concluded that the incorporation of bioactive glass particles at a concentration of 0.5% in the adhesive system, increased the bond strength of the adhesive interface and showed antibacterial activity (CFU), however, in different concentrations, did not influence the degree of conversion of the adhesive (AU)

Adhesive systems effect over bond strength of resin-infiltrated and de/remineralized enamel.

Background: The purpose of this study was to evaluate the effect of different bonding agents on bond-strength to demineralized enamel after remineralizing treatments and resin infiltration. Methods: Buccal enamel of 120 bovine incisors was polished and then were divided into five experimental groups: SE (sound enamel); DE (demineralized enamel); AS (demineralized enamel immersed in artificial saliva for eight weeks); NaF (demineralized enamel treated with 0.05% sodium fluoride solution (one minute) for eight weeks); Ic (demineralized enamel infiltrated with a low-viscosity resin (Icon-DGM). These groups were subdivided according to adhesive system used: self-etching adhesive Adper Easy One (3M/ESPE) and etch-and-rinse adhesive Single Bond (3M/ESPE). The composite resin blocks were fabricated using a Teflon matrix. A thermomechanical cycling machine was used to carry out the artificial aging of the specimens and thus were sectioned into sticks. The microtensile tests were performed using a universal testing machine at a cross-head speed of 1 mm/min. Data (in MPa) were subjected to two-way ANOVA and Tukey's tests (5%). Results: Significant differences were found for both factors tested and interactions (p<0.05). Tukey's test results of µTBS (mean ± SD) were: etch-and-rinse SE (28.79±3.93); DE (30.41±7.22); AS (29.03±3.33); NaF (29.81±4.06)a; Ic (29.47±5.5);  and self-etching SE (30.37±6.96); DE (14.62±4.47); AS (9.79±2.32); NaF (9.36±2.31); Ic (30.78±8.68).   Conclusions: Resin infiltration did not affect the bond strength of demineralized enamel for both adhesive systems tested. For etch-and-rinse adhesive, no differences were observed for the tested groups. For self-etching adhesive, only the resin-infiltrated group showed similar bond strength to sound enamel. Both etch-and-rinse and self-etching adhesive systems can be used in resin-infiltrated enamel, if a composite restoration needs to be further performed. In enamel that has undergone the de/remineralization process, the use of a total-etch adhesive might be preferable for the restorative procedure.

Previsibilidade em resolução estética para recessões gengivais / Predictability in esthetic solutions for gingival recessions: a case report

A recessão gengival é uma queixa relativamente comum entre os pacientes quando procuram o cirurgião-dentista, e os motivos desse incômodo são sensibilidade e estética. Os autores relatam que o tratamento de recessões gengivais posteriores bilaterais são realizados a partir do transplante do tecido conjuntivo subepitelial. Já a técnica operatória utilizada nesse caso, para o posicionamento do tecido conjuntivo, foi a de Langer, com reposicionamento coronário do retalho. Houve um aumento considerável com relação ao recobrimento radicular, sugerindo um processo de reparação da recessão gengival bilateral, com a interposição do tecido conjuntivo na área receptora. Em relação à praticidade, a técnica de Langer mostra-se mais fácil de ser realizada com relação ao aspecto estético, recobrimento, ganho em altura e espessura. O objetivo desse trabalho é relatar um caso clínico de resolução estética para recessão gengival. A terapia inicial do presente caso consistiu em instruções de higiene oral acompanhado de raspagem dos dentes nos 30 dias anteriores à cirurgia. Os procedimentos cirúrgicos foram feitos seguindo técnica consagrada pela ciência. O enxerto de tecido do palato foi transplantado para a região de recessão, a fim de recobrir as áreas de exposição radicular. O paciente recebeu instruções de cuidados de higiene. Após 14 dias do pós-cirúrgico, realizou-se a remoção dos pontos e uma instrução para higiene permanente do local. O resultado clínico foi uma boa estética para o paciente. Geralmente não possui recidiva mediante cuidados no controle de higiene oral e hábitos.

Gingival recession is a relatively common complaint for patients seeking treatment due to sensitivity and esthetics. The authors report that the treatment of bilateral posterior gingival recessions is performed using the subepithelial connective tissue grafting. The operative technique used in this case was the Langer's method with coronary flap repositioning. There was a considerable increase regarding root coverage, suggesting repair process of the bilateral gingival recession with the interposition of connective tissue in the recipient area. In relation to clinical aspects, the Langer's technique is easier to be performed in relation to the esthetic aspect, coverage, and gains in height and thickness. The purpose of this paper is to report a clinical case to solve the gingival recession. The initial therapy consisted of oral hygiene instructions and root planning 30 days prior to surgery. Afterwards, the surgical procedures were performed accordingly. The graft was harvested from the palate and transplanted to the recession area to cover the areas of root exposure. After 14 days, sutures were removed and oral hygiene instruction was recommended. The clinical results were excellent in terms of esthetics. Generally, no relapse was observed after good oral hygiene and habits.