Effect of nano-modified titanium surface with alkali heat treatment on early adhesion and growth of osteoblasts / 中国组织工程研究

BACKGROUND:Nanostructure modification of pure titanium surface is a hot research field of titanium implant surface treatment. OBJECTIVE:To evaluate the effect of nano-modified titanium surface treated with alkali heat treatment on early adhesion and growth of osteoblasts. METHODS:Four-grade pure titanium sheets with a diameter of 15 mm and a thickness of 1.5 mm were taken and processed in three groups:the smooth treatment group was polished step by step with 250 mesh,800 mesh,and 1 500 mesh silicon carbide sandpaper.In the sandblasting group,the smoothed titanium sheet was sandblasted with 100 μm Al2O3 particles at 0.45 MPa pressure,and then the acid etching was carried out.In the alkali heat treatment group,the smoothed titanium sheet was placed in the reactor,immersed in 10 mol/L NaOH solution,and heated in the oven at 100 ℃for 12 hours.The surface morphology,roughness,and hydrophilicity of three groups of titanium sheets were measured.MG63 osteoblasts were inoculated on the surface of three groups of titanium tablets,and the adhesion of the cells was observed by immunofluorescence staining. RESULTS AND CONCLUSION:(1)Scanning electron microscopy showed that the surface of titanium sheets in the smooth treatment group had uniform scratches;the surface of titanium sheets in the sandblasting group was uneven,and the surface of titanium sheets in the alkali heat treatment group had uniform nanoscale three-dimensional pore morphology.The roughness value of the titanium sheets in sandblasting and alkali heat treatment groups was higher than that in the smooth treatment group(P<0.05),and the water contact angle was lower than that in the smooth treatment group(P<0.05).(2)Immunofluorescence staining after 3 and 6 hours of inoculation of MG63 cells showed that the number of adhesion cells on the surface of the titanium sheet in the sandblasting group and alkali heat treatment group was higher than that in the smooth treatment group(P<0.05).Immunofluorescence staining 12 hours after inoculation showed that compared with the smooth treatment group,the actin skeleton of cells on the surface of titanium sheets in the sandblasting group and alkali heat treatment group was more extended,and most cells extended stronger pseudopodia,which was conducive to subsequent intercellular signal transduction and intercellular interaction.(3)The results showed that the nanostructures with certain biological activity could be prepared on the surface of a titanium sheet by alkali heat treatment,which was conducive to the early adhesion of osteoblasts.

Preheated acid associated with silane and electric current in the adhesion of the resin cement to ceramic

Abstract This study verified the effect of the combination of preheated hydrofluoric acid/silane/electric current in the adhesion of the resin cement to ceramic. IPS E.max Press ceramic discs embedded in PVC rigid tubes were divided into four groups associating preheated hydrofluoric acid and silane applied with electrical current (n=10): Ha+S (Heated acid + silane); Ha+S+Ec (Heated acid + silane + electrical current); A+S (Acid + silane) and A+S+Ec (Acid + silano + electrical current). Resin cement/ceramic samples were stored in water at 37°C for 24h. After storage, they were submitted to the microshear test, fracture analysis, and contact angle at 24h or after thermocycling (10,000 cycles/5-55ºC). Bond strength data were evaluated by two-way ANOVA. For comparison between evaluation times (24h or thermocycling) was applied unpaired t-test. A significance post-hoc test of p=0.05 was assumed for analyses and graphs (GraphPad Prism 9.0 software). At 24h, the microshear strength showed similar values between Ha+S, Ha+S+Ec, and A+S+Ec groups, while A+S showed the lowest value with a statistical difference. After thermocycling, Ha+S and Ha+S+Ec were similar, as well as A+S and A+S+Ec. There was a significant difference in all groups comparing 24h (highest value) with after thermocycling (lowest value). Adhesive fracture was predominant in all groups and evaluation times. Ha+S and A+S groups showed higher contact angle values compared to the Ha+S+Ec and A+S+Ec with lower values. In conclusion, the association of preheated hydrofluoric acid/silane applied or not with electric current promoted different microshear strength values, fracture types, and contact angles in the resin cement/ceramic bond.

Resumo Este estudo verificou o efeito da combinação ácido fluorídrico pré-aquecido/silano/corrente elétrica na adesão do cimento resinoso à cerâmica. Os discos cerâmicos IPS E.max Press embutidos em tubos rígidos de PVC foram separados em quatro grupos associando ácido fluorídrico pré-aquecido e silano aplicado com corrente elétrica (n=10): Ha+S (ácido aquecido + silano); Ha+S+Ec (Ácido aquecido + silano + corrente elétrica); A+S (Ácido + silano) e A+S+EC (Ácido + silano + corrente elétrica). Amostras de cimento resinoso/cerâmica foram armazenadas em água a 37°C por 24 horas. Após o armazenamento foram submetidas ao ensaio de micro cisalhamento, análise de fratura e ângulo de contato no período de 24 horas ou após termociclagem (10.000 ciclos/5-55ºC). Os dados de resistência de união foram avaliados por ANOVA dois fatores. Para comparação entre os tempos de avaliação (24 horas ou termociclagem) foi aplicado o teste t não pareado. Foi assumida significância de 5% para análises e gráficos (software GraphPad Prism 9.0). Em 24 horas, a resistência ao micro cisalhamento apresentou valores similares entre os grupos Ha+S, Ha+S+Ec e A+S+Ec, enquanto A+S apresentou menor valor com diferença estatística. Após a termociclagem, Ha+S e Ha+S+Ec foram similares, assim como A+S e A+S+Ec. Houve diferença significativa em todos os grupos comparando 24 horas (maior valor) com após termociclagem (menor valor). A fratura adesiva foi predominante em todos os grupos e tempos de avaliação. Os grupos Ha+S e A+S apresentaram maiores valores de ângulos de contato comparados aos grupos Ha+S+Ec e A+S+Ec com valores menores. Em conclusão, a associação ácido fluorídrico pré-aquecido/silano aplicado com corrente elétrica promoveu diferentes valores de resistência ao micro cisalhamento, tipos de fratura e ângulos de contato na adesão do cimento resinoso à cerâmica.

Evaluation the stress distribution in root canals by 3D finite element analysis after the materials used in reattaching the vertically root fractured fragments

Abstract The aim was to evaluate the effect of stress distribution on vertical, horizontal, and oblique forces on the tooth model after reattaching the fragments of the maxillary incisor with vertical root fracture (VRF) using different materials, by 3D finite element analysis (FEA). Tooth with a root canal, spongious, and cortical bone models were designed. VRF was modeled on a tooth with 4 different re-attachment models: Group 1: dual-cure cement (DC)+fiber reinforced composite (FRC), Group 2: DC+polyethylene fiber, Group 3: DC+glass fiber, and Group 4:DC. 100 N force was applied in 3 different directions. Maximum principal stresses (σmax) of dentin, and re-attachment materials were evaluated on colored images. The highest σmax values ​​were on the repair materials under vertical forces for Groups 1 and 4, respectively; Groups 2 and 3 showed similarity. The highest σmax values in repair materials under horizontal and oblique forces were observed in Group 3 however the lowest σmax values in repair materials under oblique and horizontal forces were observed in Group 1. The stress values ​​on repair materials gradually increased respectively starting from horizontal to vertical. As the elasticity modulus of the repair materials increased, the stress values ​​on root dentin increased. Through all force directions, except vertical forces, lower stress values were observed with FRC. The fracture resistance was bigger when using solely FRC or dual-cure resin cement in comparison to fiber-supported designs. Adding polyethylene fiber to re-restorations decreased stress values ​​compared to glass fiber addition. Therefore, when adding fibers, polyethylene fiber will be advantageous.

Resumo O objetivo foi avaliar o efeito da distribuição de estresse nas forças verticais, horizontais e oblíquas no modelo de dente após a recolocação dos fragmentos do incisivo superior com fratura radicular vertical (FRV) usando diferentes materiais, por meio da análise de elementos finitos (FEA) em 3D. Métodos: Foram projetados modelos de dentes com canal radicular, osso esponjoso e cortical. A FRV foi modelada em um dente com 4 modelos diferentes de reataque, como Grupo 1: cimento de cura dupla (DC) + compósito reforçado com fibra (FRC), Grupo 2: DC + fibra de polietileno, Grupo 3: DC + fibra de vidro e Grupo 4: DC. Foi aplicada uma força de 100 N em 3 direções diferentes. As tensões principais máximas (σmax) da dentina e os materiais de recolocação foram avaliados em imagens coloridas. Resultados: Os valores mais altos de σmax foram registrados nos materiais de reparo sob forças verticais para os Grupos 1 e 4, respectivamente; os Grupos 2 e 3 apresentaram semelhança. Os valores mais altos de σmax nos materiais de reparo sob forças horizontais e oblíquas foram observados no Grupo 3; no entanto, os valores mais baixos de σmax nos materiais de reparo sob forças oblíquas e horizontais foram observados no Grupo 1. Os valores de tensão nos materiais de reparo aumentaram gradualmente, respectivamente, começando da holizontal para a vertical. À medida que o módulo de elasticidade dos materiais de reparo aumentava, os valores de tensão na dentina da raiz aumentavam. Em todas as direções de força, exceto nas forças verticais, foram observados valores de tensão mais baixos com o FRC. Conclusões: a resistência à fratura foi maior quando se utilizou apenas FRC ou cimento resinoso de cura dupla em comparação com os designs com suporte de fibra. A adição de fibra de polietileno às restaurações diminuiu os valores de tensão em comparação com a adição de fibra de vidro. Portanto, ao adicionar fibras, a fibra de polietileno será vantajosa.

Impact of Access Cavity Design on Fracture Resistance of Endodontically Treated Maxillary First Premolar: In Vitro

Abstract This study was designed to investigate the impact of access cavity designs on fracture resistance of endodontically treated maxillary first premolars. The study sample consisted of 72 intact maxillary first premolars, randomly divided into six groups (n = 12). A standardized proximal cavity preparation was prepared for all samples using standard bur. Groups I: control group with only standard proximal cavity and no endodontic access, group II: Truss access cavity, group III: Separated access to buccal and palatal canals without removal of dentine in between, group IV: Access to buccal and palatal canals with removal of dentine in between, group V: Traditional access cavity, group VI: Mesio-occlusal-distal cavity (MOD). For groups I and VI, only composite restoration was used to restore the proximal cavity, while for groups II- V, the access was prepared and endodontic treatment was performed on all teeth, then composite restoration was placed. The root canals were instrumented using nickel-titanium files, irrigated with sodium hypochlorite, and filled with AH plus sealer and gutta-percha using warm vertical condensation. All samples were then placed in an acrylic mold and underwent thermal aging for 10,000 cycles between 5 and 55°C. The samples were fixed in a universal testing machine with the long axis of the roots positioned at 20° to a load applied at a crosshead speed of 1 mm/min using a stainless steel semi-spherical indenter (Ø = 3 mm) until fracture occurred to determine the fracture resistance force in Newton. The normality test (Shapiro-Wilk) showed that data are normally distributed. Group II exhibited the highest mean fracture resistance, and group VI was the least likely to resist the fracture. No statistically significant differences between tested groups (p-value = 0.237). The MOD group showed a more unfavorable mode of fracture compared to other groups. No significant difference in fracture resistance between conservative and traditional access cavities. The missing marginal ridges, such as in MOD cavities played an important role in decreasing the fracture resistance of endodontically treated teeth.

Resumo O objetivo deste estudo foi investigar o impacto do design da cavidade de acesso na resistência à fratura de primeiros pré-molares superiores tratados endodonticamente. MÉTODOS: A amostra do estudo consistiu em 72 primeiros pré-molares superiores intactos, divididos aleatoriamente em seis grupos (n = 12). Um preparo padronizado da cavidade proximal foi realizado para todas as amostras usando broca padrão. Grupos I: grupo de controle com apenas cavidade proximal padrão e sem acesso endodôntico, grupo II: cavidade de acesso Truss, grupo III: acesso separado aos canais vestibular e palatino sem remoção de dentina entre eles, grupo IV: acesso aos canais vestibular e palatino com remoção de dentina entre eles, grupo V: cavidade de acesso tradicional, grupo VI: cavidade mesio-oclusal-distal (MOD). Para os grupos I e VI, apenas a restauração de compósito foi usada para restaurar a cavidade proximal. Já nos grupos II e V, o acesso foi preparado e o tratamento endodôntico foi realizado em todos os dentes e, em seguida, foi colocada a restauração de resina composta. Os canais radiculares foram instrumentados com limas de níquel-titânio, irrigados com hipoclorito de sódio e preenchidos com AH plus sealer e guta-percha usando condensação vertical quente. Todas as amostras foram então colocadas em molde de acrílico e submetidas a envelhecimento térmico por 10.000 ciclos entre 5 e 55°C. As amostras foram fixadas em uma máquina de teste universal com o eixo longo das raízes posicionado a 20° para uma carga aplicada a uma velocidade de cruzeta de 1 mm/min usando indentador semiesférico de aço inoxidável (Ø = 3 mm) até que ocorresse a fratura para determinar a força de resistência à fratura em Newton. RESULTADOS: O teste de normalidade (Shapiro-Wilk) mostrou que os dados são normalmente distribuídos. O grupo II apresentou a maior resistência média à fratura, e o grupo VI foi o menos propenso a resistir à fratura. Não houve diferenças estatisticamente significativas entre os grupos testados (p-valor = 0,237). O grupo MOD apresentou um modo de fratura mais desfavorável em comparação com os outros grupos. CONCLUSÕES: Não houve diferença significativa na resistência à fratura entre as cavidades de acesso conservador e tradicional. A ausência de cristas marginais, como nas cavidades MOD, desempenhou um papel importante na diminuição da resistência à fratura dos dentes tratados endodonticamente.

Longitudinal bond strength of a universal adhesive and chemical dentin characterization under different acid etching protocols

Abstract Objective This study aimed to analyze the longitudinal bond strength of a universal adhesive and chemically characterize the dentin substrate under different acid etching protocols. Methodology Dentin samples were etched with polyacrylic acid 25% (PAA) for 10 seconds (n=3) and phosphoric acid 32% (PA) for 15 seconds (n=3) and analyzed by Fourier transform infrared spectroscopy - attenuated total reflectance (FTIR-ATR) before and after treatment. For collagen degradation, samples (n=12) were divided into 3 groups: PAA, PA, and Deionized water (control), and analyzed by the quantity of solubilized type I collagen C-terminal cross-linked telopeptides and solubilized C-terminal peptide in relation to total protein concentration (ICTPtp and CTXtp) and by their ultimate tensile strength (UTS). For the adhesive interface analysis, dentin samples (n=72) were divided into 3 groups: PAA, PA, and Self-etch (SE), and subdivided into 2 groups: 24 h (baseline) and 1 year. The following tests were performed: microtensile bond strength (μTBS) (n=48), scanning electron microscopy (SEM) (n=12), and nanoleakage (n=12). Results The FTIR of PAA showed lower reduction of the peaks in the phosphate group when compared to PA. For ICTPtp, PA showed a significantly higher value. For CTXtp, PA and PAA groups failed to statically differ from each other. UTS was significantly lower for PA. For μTBS, storage time significantly affected bond strength. The results were unaffected by the etching protocol. For SEM, after 1 year, PA had little evidence of degradation in the upper third of the adhesive interface in comparison to the other groups. Nanoleakage showed no considerable silver impregnation after 1 year in the SE group. Conclusion The use of PAA prior to a universal adhesive (when compared to PA) represents a less aggressive type of etching to dentin. However, self-etching still seems to be the best option for universal adhesive systems that have functional monomers in their composition.

Effect of hydrofluoric acid concentration and aging on the bond strength ceramics to a resin cement

Abstract This study evaluated the influence of hydrofluoric acid (HF) concentration and thermal cycling on the microshear bond strength (µSBS) of a resin luting agent to IPS e.max® CAD and Rosetta® SM. Ceramic specimens (12.0 x 14.0 x 1.5mm) were randomized into 8 groups (n=10) according to HF concentration, commercial brand, and aging. Immediately after polishing, and etching, all specimens were silanized and a layer of adhesive was applied. A PVS mold of 3 mm thickness and 10mm diameter with (four) 1.0mm holes was fabricated, placed on each specimen, and then filled with a resin luting agent. Half of the specimens were subjected to the µSBS test using an Instron at a speed of 1.0 mm/min, following a 24-hour storage in deionized water at 37ºC. The remaining specimens were subjected to thermal cycling (5ºC-55ºC, 30 seconds per bath) and µSBS. The data were evaluated utilizing a three-way ANOVA and Tukey's post-hoc test (α=0.05). Significant differences were found for HF concentration and aging (p<0.0001). No significant difference in µSBS was found for commercial brands (p=0.085). The interaction between brand and HF concentration (p=0.358), brand and aging (p=0.135), and HF concentration and aging (p=0.138) were not statistically significant. The triple interaction among these factors was not statistically significant (p=0.610). In conclusion, the bond strength is affected by the HF concentration. No statistical difference was observed between the two ceramics. Thermal cycling significantly reduced µSBS.

Resumo Este estudo avaliou a influência da concentração do ácido fluorídrico (AF) e da ciclagem térmica na resistência de união ao microcisalhamento (RUµC) de um cimento resinoso para IPS e.max® CAD e Rosetta® SM. Espécimes cerâmicos (12,0 x 14,0 x 1,5mm) foram divididos em 8 grupos (n=10) de acordo com concentração do HF, marca comercial e envelhecimento. Imediatamente após o polimento e condicionamento ácido, todos os espécimes foram silanizados e uma camada de adesivo foi aplicada. Um molde PVS de 3 mm de espessura e 10 mm de diâmetro com (quatro) orifícios de 1,0 mm foi confeccionado, colocado em cada espécime e preenchido com o cimento resinoso. Metade dos espécimes foi submetida ao teste RUµC na Instron a velocidade de 1,0 mm/min, após 24 horas de armazenamento em água deionizada a 37ºC. Os espécimes restantes foram submetidos a ciclagem térmica (5ºC-55ºC, 30 segundos por banho) e a RUµC. Os dados foram avaliados por ANOVA de três fatores e ao teste post-hoc de Tukey (α=0,05). Diferenças significativas foram encontradas para concentração de HF e envelhecimento (p<0,0001). Nenhuma diferença significativa na RUµC foi encontrada para cada marca comercial (p=0,085). A interação entre marca comercial e a concentração do HF (p=0,358), marca comercial e envelhecimento (p=0,135) e concentração do HF e envelhecimento (p=0,138) não foram estatisticamente significativas. A tripla interação entre esses fatores não foi estatisticamente significativa (p=0,610). Concluindo, a resistência de união é afetada pela concentração de HF. Não foi observada diferença estatística entre as duas cerâmicas. A ciclagem térmica reduziu significativamente a resistência de união ao microcisalhamento.

Cytotoxic effects on human dental pulp stem Cells after exposure to adhesive bonding agents

Abstract Studies regarding cytotoxic effects attributed to the use of adhesive bonding agents on pulp tissue are not conclusive. To point out whether these materials are safe for clinical use, in vivo exposure of dental pulp to adhesive bonding agents was simulated using an experimental setup in which Human Dental Pulp Stem Cells (hDPSC) are exposed to the action of two kinds of adhesives: self-etching adhesives and two-step bonding agents through a dentine barrier. Cytotoxic effects on these cells were evaluated by MTT assay protocol and fluorescence microscopy, and their results were contrasted to those obtained through Raman spectra taken on single hDPSCs. Overall, no significant cytotoxic effects were observed by combining all the techniques, and cell viability close to 90% was achieved for a dentine barrier of at least 1 mm thick. Moreover, Raman spectroscopy was able to detect structural DNA damage in some dental pulp cells when exposed to two-step bonding agents, suggesting that this technique could be considered a complementary tool with the potential to evaluate cell toxicity beyond cell viability.

Resumo Os estudos sobre os efeitos citotóxicos atribuídos ao uso de agentes de união adesivo no tecido pulpar não são conclusivos. Para determinar se esses materiais são seguros para uso clínico, a exposição in vivo da polpa dentária a agentes de união adesiva foi simulada por meio de uma configuração experimental na qual as células-tronco da polpa dentária humana (hDPSC) são expostas à ação de dois tipos de adesivos: adesivos autocondicionantes e agentes de união de duas etapas por meio de uma barreira de dentina. Os efeitos citotóxicos nessas células foram avaliados pelo protocolo de ensaio MTT e microscopia de fluorescência, e seus resultados foram contrastados com os obtidos por meio de espectros Raman obtidos em hDPSCs individuais. De modo geral, não foram observados efeitos citotóxicos significativos com a combinação de todas as técnicas, e a viabilidade celular próxima a 90% foi obtida para uma barreira de dentina de pelo menos 1 mm de espessura. Além disso, a espectroscopia Raman foi capaz de detectar danos estruturais ao DNA em algumas células da polpa dentária quando expostas a agentes de colagem de duas etapas, sugerindo que essa técnica poderia ser considerada uma ferramenta complementar com potencial para avaliar a toxicidade celular além da viabilidade celular.

Application of proanthocyanidin in the treatment and repair of deep caries / 口腔疾病防治

@#Proanthocyanidin (PA), as a kind of natural plant polyphenol, have a variety of biological functions, such as promoting remineralization, inducing collagen cross-linking, inhibiting protease activity and inhibiting bacteria. Therefore, PA could be broadly used in the clinical application of treatment and repair of deep caries in the future; for example, PA could promote dentin remineralization, improve resin-dentin bonding durability and improve the dentin acid erosion effect. This application potential of PA arises from several features, firstly, PA can not only promote dentin remineralization on its own or with other remineralizers but also exhibits antibacterial effects, which can inhibit acid production while reducing the formation of cariogenic pathogens and their biofilms. Based on the above features, PA can reduce the incidence of caries disease; thus, PA improves deep caries and long-term effects after treatment. In addition, PA added to adhesives or etch agents can improve the etching and bonding effect of dentin by inducing collagen cross-linking and inhibiting protease activity, thus achieving the ultimate goal of improving the bonding performance of deep caries. This paper summarizes recent progress of research on PA for the treatment and repair of deep caries, including the promotion of dentin remineralization and antibacterial activity as well as the improvement in dentin bonding and acid etching effect, to provide a more comprehensive reference for treating and restoring deep caries in clinical practice.

Effect of Neodymium-Doped Yttrium Aluminum Garnet Laser Combined With Desensitizing Toothpaste on Dentinal Tubule Occlusion Against Acid Challenge / 中国医学科学院学报

Objective To assess the effects of different application sequences of neodymium-doped yttrium aluminum garnet(Nd∶YAG)laser and the desensitizing toothpaste containing stannous fluoride on dentinal tubule occlusion.Methods Twelve intact third molars freshly extracted from human were selected and prepared into dentin slices with a thickness of 0.8 mm.Each dentin slice was subdivided into four small slices,three of which were etched with 6% citric acid and randomly assigned to the following three groups(n=12):(1)control group:no treatment;(2)Nd∶YAG+toothbrushing(TB)group:first irradiated with Nd∶YAG laser and then brushed with desensitizing toothpaste;(3)TB+Nd∶YAG group:first brushed with desensitizing toothpaste and then irradiated with Nd∶YAG laser.The Nd∶YAG laser irradiation were carried out at 1 W,15 pulses/s,and the pulse width of 150 μs for 10 s(for a total of 6 cycles).After the above treatment,the 12 dentin slices from the Nd∶YAG+TB and TB+Nd∶YAG groups were randomly assigned to four subgroups(n=3)and subjected to acid etching in the Coca-Cola solution for 0,5,10,and 15 min.A scanning electron microscope was used to observe and photograph the dentin slices in each group,and eight single-blinded examiners scored the slices according to uniform criteria.The analysis of variance was carried out to compared the scores between groups.Results Before acid etching,the dentin tubule occlusion scores of the Nd∶YAG+TB and TB+Nd∶YAG groups were(4.83±0.09) scores and(3.85±0.66) scores,respectively,which had no significant difference between each other(P=0.0590)and were higher than that[(0.10±0.07)scores]of the control group(both P<0.0001).The dentin tubule occlusion scores of the Nd∶YAG+TB group after acid etching for 5,10,and 15 min were(4.33±0.60)scores,(4.27±0.24)scores,and(3.63±0.07)scores,respectively,which were not significantly different from those[(4.04±0.10)scores,(3.76±0.59)scores,and(3.17±0.29)scores,respectively]of the TB+Nd∶YAG group(all P>0.05).In the Nd∶YAG+TB subgroup,the dentin tubule occlusion score after acid etching for 15 min was significantly lower than that before acid etching(P=0.0011).In the TB+Nd∶YAG group,there was no statistically significant difference in the score between before and after acid etching(P>0.05).Conclusions Nd∶YAG laser irradiation with appropriate parameters combined with the use of desensitizing toothpaste could produce an excellent occluding effect on dentinal tubules regardless of the sequence.However,brushing with desensitizing toothpaste followed by Nd∶YAG laser irradiation produced more consistent dentin sealing after acid etching.

Bonding performance of universal adhesives with concomitant use of silanes to CAD/CAM blocks / Associação de adesivos universais com silanos na adesão em blocos de CAD/CAM

ABSTRACT Objective: This study assessed whether the use of a silane coupling agent influence the bond strength of two universal adhesives to ceramic or resin CAD/CAM blocks. Methods: Forty-eight samples were obtained from each resin nano-ceramic hybrid block (RCBs) and lithium disilicate ceramic blocks (LD). Samples were treated with silane with MDP (Monobond - S-MDP), silane without MDP (Prosil - PS), and no silane application (Control - Ctr) followed by universal adhesive with silane (UAS) and without silane (UA) (n=8). Three polyurethane tubes (1.5 mm of internal diameter) were positioned in each sample treated surface and filled with a dual cured resin cement. Bond strength was assessed by microshear bond strength test and failure analysis was performed for all samples. Results: For the RCBs, UAS presented the highest bond strength values (p=0.004). Silane application was not significant in bond strength values (p=0.444). For LD, silane application was significant in bond strength values (p<0.001), but the adhesive was not (p=0.066). Failure analysis showed high prevalence of adhesive failures for both substrates. Conclusion: A silane-containing universal adhesive promoted the best bond strength results to the resin nano-ceramic hybrid block. For bonding to a glass-ceramic CAD/CAM material, additional silane (without MDP) application presented the best results.

RESUMO Objetivo: Este estudo avaliou se o uso de um agente de união silano influencia na resistência de união de dois adesivos universais a blocos CAD/CAM cerâmicos ou resinosos. Métodos: Quarenta e oito amostras foram obtidas de blocos resinosos (RCBs) e cerâmicos de dissilicato de lítio (LD). As amostras foram tratadas com silano contendo: MDP (Monobond - S-MDP), silano sem MDP (Prosil - PS) ou sem aplicação de silano (Control - Ctr) seguido de adesivo universal com silano (UAS) ou sem silano (UA) (n=8). Três tubos de poliuretano (1,5 mm de diâmetro interno) foram posicionados em cada superfície tratada da amostra e preenchidos com um cimento resinoso dual. A resistência de união foi avaliada pelo teste de microcisalhamento e a análise de falha foi realizada para todas as amostras. Resultados: Para os RCBs, UAS apresentou os maiores valores de resistência de união (p=0,004). A aplicação de silano não foi significativa nos valores de resistência adesiva (p=0,444). Para LD, a aplicação de silano foi significativa nos valores de resistência de união (p<0,001), mas o adesivo não (p=0,066). A análise de falhas mostrou alta prevalência de falhas adesivas para ambos os substratos. Conclusão: O adesivo universal contendo silano promoveu os melhores valores de resistência adesiva ao bloco de resina. Para o bloco cerâmico, a aplicação adicional de silano (sem MDP) apresentou melhores resultados.

Survival rate and stability of surface-treated and non-surface-treated orthodontic mini-implants: a randomized clinical trial

ABSTRACT Objectives: This clinical trial was conducted to evaluate the stability and failure rate of surface-treated orthodontic mini-implants and determine whether they differ from those of non-surface-treated orthodontic mini-implants. Trial Design: Randomized clinical trial with a split-mouth study design. Setting: Department of Orthodontics, SRM Dental College, Chennai. Participants: Patients who required orthodontic mini-implants for anterior retraction in both arches. Methods: Self-drilling, tapered, titanium orthodontic mini-implants with and without surface treatment were placed in each patient following a split-mouth design. The maximum insertion and removal torques were measured for each implant using a digital torque driver. The failure rates were calculated for each type of mini-implant. Results: The mean maximum insertion torque was 17.9 ± 5.6 Ncm for surface-treated mini-implants and 16.4 ± 9.0 Ncm for non-surface-treated mini-implants. The mean maximum removal torque was 8.1 ± 2.9 Ncm for surface-treated mini-implants and 3.3 ± 1.9 Ncm for non-surface-treated mini-implants. Among the failed implants, 71.4% were non-surface-treated mini-implants and 28.6% were surface-treated mini-implants. Conclusion: The insertion torque and failure rate did not differ significantly between the groups, whereas the removal torque was significantly higher in the surface-treated group. Thus, surface treatment using sandblasting and acid etching may improve the secondary stability of self-drilling orthodontic mini-implants. Trial registration: The trial was registered in the Clinical Trials Registry, India (ICMR NIMS). Registration number: CTRI/2019/10/021718

RESUMO Objetivos: Este ensaio clínico foi conduzido para avaliar a estabilidade e a taxa de falha de mini-implantes ortodônticos com superfície tratada, e determinar se elas diferem das dos mini-implantes ortodônticos sem superfície tratada. Desenho do estudo: Ensaio clínico randomizado com desenho de boca dividida. Instituição: Department of Orthodontics, SRM Dental College, Chennai/India. Participantes: Pacientes que necessitavam de mini-implantes ortodônticos para retração anterior em ambas as arcadas. Métodos: Mini-implantes ortodônticos autoperfurantes, cônicos, de titânio com ou sem tratamento de superfície, foram colocados em cada paciente, seguindo um desenho de boca dividida. Os torques máximos de inserção e de remoção foram medidos para cada mini-implante, usando um torquímetro digital. As taxas de falha foram calculadas para cada tipo de mini-implante. Resultados: O valor médio do torque máximo de inserção foi de 17,9 ± 5,6 Ncm para mini-implantes com superfície tratada e 16,4 ± 9,0 Ncm para mini-implantes sem superfície tratada. O valor médio do torque máximo de remoção foi de 8,1 ± 2,9 Ncm para mini-implantes com superfície tratada e 3,3 ± 1,9 Ncm para mini-implantes sem superfície tratada. Entre os implantes que falharam, 71,4% eram mini-implantes sem superfície tratada e 28,6% eram mini-implantes com superfície tratada. Conclusão: O torque de inserção e a taxa de falha não diferiram significativamente entre os grupos; porém, o torque de remoção foi significativamente maior no grupo com superfície tratada. Assim, o tratamento de superfície com jateamento e condicionamento ácido pode melhorar a estabilidade secundária dos mini-implantes ortodônticos autoperfurantes. Registro do estudo: Esse estudo foi registrado no Clinical Trials Registry, Índia (ICMR NIMS). Número de registro: CTRI/2019/10/021718

Acid-Base Resistant Zone in Teeth with the Direct Restoration Using Different Adhesive System Generations: A Systematic Review

ABSTRACT Objective: To find out what the acid-base resistant zone (ABRZ) is and the mechanism of its formation. Material and Methods: This systematic review was based on the search of laboratory studies in which selfetching adhesive systems were used. The electronic database PubMed was used for the search. The search began on August 2021 and ended on June 2022. We have analyzed the materials and methods of each research and entered them in the appropriate tables to give a clearer assessment of the obtained results. Results: This systematic review included 15 full-text articles published from 2011 to 2019. The ABRZ is formed on both dentine and enamel. On dentine, the ABRZ is formed only when using self-etching adhesive systems; on the enamel, on the contrary, the step of preliminary etch and rinse contributes to the formation of a thicker ABRZ. The functional monomer MDP and fluorine increase the thickness of the ABRZ and provide a hybrid layer /ABRZ boundary without defects and erosions. Conclusion: Self-etching adhesive systems ensure the creation of an ABRZ resistant to acid-base tests. This phenomenon can provide the resistance of tooth tissues to demineralization, and therefore increase their resistance to caries.

Uso de adhesivo universal con pregrabado y autograbado en tejidos duros del diente / Use of universal adhesive with pre-etch and self etch strategies on hard tooth tissues

RESUMEN Introducción: Buscando satisfacer la demanda con procedimientos adhesivos más rápidos, menos sensibles a la técnica y facilidad de uso, se han desarrollado los adhesivos universales, que brindan al profesional la opción de seleccionar la estrategia de adhesión con diferentes modos de grabado, ya sea con grabado y enjuague, autograbado o grabado selectivo. Debido a la poca información existente, se han generado dudas sobre el rendimiento, propiedades y la aplicación de una técnica adhesiva adecuada sobre los tejidos dentales. Objetivo: Determinar el nivel de adhesión con el uso de adhesivos universales en modo de grabado y enjuague y autograbado. Métodos: Se realizó una revisión de la literatura, a través de la búsqueda electrónica en las bases de datos: SciELO, Scopus, PubMed, Springer y EBSCO. Inicialmente se seleccionaron por título y resumen, artículos duplicados se consideraron solo una vez, se incluyeron artículos de acceso libre y pagos, escritos en idioma español e inglés, publicados desde el año 2015, de los cuales 39 artículos fueron seleccionados para el estudio. Conclusiones: El uso de adhesivos universales sobre dentina presenta un nivel de adhesión mayor cuando se aplica en modo de autograbado. La aplicación activa del adhesivo universal en esmalte mejora la fuerza y resistencia de unión. El nivel de adhesión en el esmalte es mayor cuando se aplica en modo de grabado y enjuague. La resistencia inicial y por fatiga del adhesivo, no mejora con los tiempos prolongados del grabado ácido.

ABSTRACT Introduction: universal adhesives have been developed to satisfy the demand with faster adhesive procedures, less sensitive to the technique and ease of use, which offer the professional the option of selecting the adhesion strategy with different etching modes, either with etch-and-rinse, self-etch or selective etching ones. Doubts have been generated about the performance, properties and application of an adequate adhesive technique on dental tissues due to the little existing information. Objective: to determine the level of adhesion with the use of universal adhesives in etch-and-rinse and self-etch modes Methods: an electronic search of the literature was carried out in SciELO, Scopus, PubMed, Springer and EBSCO databases. Initially, articles were selected by title and abstract, duplicate ones were considered only once, free and paid access articles, written in Spanish and English and published since 2015 were included; 39 of them were selected for the study. Conclusions: the use of universal adhesives on dentin presents a higher level of adhesion when applied in self-etch mode. The active application of the universal adhesive improves the enamel bond strength. The level of adhesion on the enamel is higher when applied in etch-and-rinse. The initial fatigue resistance of the adhesive does not improve with prolonged acid etching times.

Comparación de la fuerza de adhesión a dentina de cementos de autograbado vs grabado total / Comparison of bond strength to dentin of self-etching cements vs total etching

Los sistemas cementantes han mejorado notablemente, los objetivos que persiguen los nuevos cementos es que la adhesión sea duradera y conseguir siempre que sea posible una interface cerrada con un sellado perfecto. Se han podido desarrollar nuevas técnicas y nuevos materiales de cementación que han ido perfeccionando la unión del material restaurador al diente. En el presente estudio se compara la fuerza de adhesión a dentina de cementos de autograbado y cementos de grabado total para comprobar los efectos positivos en el grabado de la dentina. Para el estudio se utilizaron dos cementos a base de resina (RelyX U200 Clicker 3M y RelyX Ultimate 3M). Se encapsularon 40 molares en acrílico en dos grupos de 20 muestras para la aplicación de dos sistemas cementantes de autograbado (grupo 1) y de grabado total (grupo 2), respectivamente, se desgastaron hasta descubrir la dentina; siguiendo las especificaciones del fabricante se colocó el cemento en cada grupo, y después se sometieron a pruebas de cizalla en una máquina de ensayo universal Instron. La medida expresada en megapascales (MPa) fue: grupo 1 = 7.5569 y grupo 2 = 12.6444. En este caso fueron analizados dos grupos, tomándose la primera significancia bilateral. Se realiza la prueba en t de Student, con 95% de intervalo de confianza en la diferencia, demostrando así que el cemento RelyX Ultimate 3M tiene mayor fuerza de adhesión que el cemento RelyX U200 Clicker 3M. Nuestra investigación fue factible y llegamos a nuestro propósito, en el cual comprobamos la mayor adhesión de cementos de grabado total, los cuales son sometidos a un previo tratamiento del diente (AU)

The effect of storage temperature and application temperature on the properties of adhesives and resin composites / 口腔疾病防治

@#The properties of adhesives and light-cured resin composites are closely related to the repair of dental defects. Therefore, improving the properties of adhesives and resins composite to increase the success rate of filling has been the focus of research in the field of prosthodontics in recent years. Current studies have confirmed that temperature can change the properties of adhesives and light-cured resin composites, affecting their repair effect. A proper storage temperature ensures the good performance of materials: the self-etching adhesive system should be refrigerated, and the light-cured resin composite should be refrigerated or stored at room temperature according to its composition, proportion and other properties; however, the appropriate storage temperature for the etch-and-rinse adhesive system is not clear. The appropriate application temperature could improve the fluidity, monomer conversion, bonding strength, compressive strength and other properties of the materials to improve the quality of filling restoration. However, there is a wide variety of adhesives and resin composites, and the effect of temperature on each material is different. Thus, it is still necessary to explore the temperature range for material storage, precooling and preheating. Few studies have been performed in vivo, and the clinical restorative effects of adhesives and resin composites stored and used at different temperatures need to be further studied.

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.

Influence of laser deproteinization of acid-etched dentin on marginal microleakage of class V composite restoration

Aim: Recent reports indicate that deproteinization of acid-etched dentin surface can extend penetration depth of adhesive agents. The main goal of the present research was to investigate the deproteinization effect of Nd:YAG and diode 940 lasers on acid-etched dentin and microleakage grade in class V composite restorations. Methods: 36 extracted human premolar teeth were selected to make standard buccal and lingual class V cavities. These samples were randomly split into three sub-groups: 1.Control group, in which composite was applied for restoration after etch and bonding process without deproteinization; 2.Nd:YAG laser group, in which the teeth were deproteinized with Nd:YAG laser after etching and painting internal surfaces of cavities with Van Geison stain and then composite restorations applied just as control group; 3.Diode laser group, in which the process was similar to Nd:YAG laser group, but instead, diode 940 laser was irradiated. The teeth were bisected into two equal longitudinal buccal and lingual halves. Marginal microleakage of samples was scored by using a stereomicroscope. Kruskal- Wallis, Mann-Whitney U and Fisher's statistical tests were employed for analysis of the obtained data. Results: A significant reduction in marginal microleakage was observed for both groups treated with laser (Nd:YAG and diode 940)compared to control (p=0.001 & p=0.047). There was no significant difference in marginal microleakage between Nd:YAG laser and diode 940groups (P = 0.333). Conclusion: Nd:YAG and diode 940 laser deproteinization of acid-etched dentin decreased the marginal microleakage of in-vitro class V resin composite restorations

The effect of acid concentration and etch time on morphology and tensile bond strength of primary dentin An in vitro study

Background: There are conflicting results concerning the ideal time for etching primary dentin and its effect on the bond strength of adhesive restorative materials. Aim: To assess in vitro, the effect of varied acid concentration and etch time on the morphological features and tensile bond strength of primary dentin. Materials and Methods: Forty healthy primary molars were prepared by exposing the dentin of the occlusal surface, creating a smear layer. A 3 mm × 3 mm test indow was demarcated, and specimens were randomly allocated to four groups (n = 10): Group 1A 10% phosphoric acid, 7 s; Group 1B 10% phosphoric acid, 15 s; Group 2A 37% phosphoric acid, 7 s and Group 2B 37% phosphoric acid, 15 s. Surface analysis was done using atomic force microscope and scanning electron microscope. For tensile bond strength evaluation, 24 specimens prepared as mentioned were mounted in acrylic blocks and allocated to four groups according to the prescribed etching protocol. Resin rods were bonded and tested in tension after 24 h (n = 6). Data were analyzed statistically using unpaired t-test. Results: Etching of primary dentin using 37% phosphoric acid for 7 s produced the highest tensile bond strength of 9.51 ± 2.19 MPa. Conclusion: Etching time of 7 s may improve the adhesion of resin restorative materials with primary dentin.

Polifluoruro de amonio como alternativa de acondicionamiento para laminados ultradelgados de disilicato de litio. Reporte de caso / Ammonium polyfluoride as an alternative for the surface conditioning of ultrathin lithium disilicate veneers. A case report

RESUMEN: Los laminados vitrocerámicos ultradelgados constituyen una alternativa conservadora para la resolución de alteraciones estéticas. Sin embargo, su acondicionamiento con ácido fluorhídrico suele no estar exento de complicaciones, por lo que el uso de un sistema autograbante en base a polifluoruro de amonio (Monobond Etch&Prime, MEP) permite disminuir el riesgo de sobregrabado, simplificando la técnica. El presente reporte presenta el seguimiento a dieciocho meses de un caso clínico resuelto mediante laminados vitrocerámicos acondicionados únicamente con MEP. Caso. Paciente joven con alteraciones estéticas en el sector anterosuperior. Se realizaron preparaciones conservadoras para la confección de laminados ultradelgados en disilicato de litio (e.maxPress). Las vitrocerámicas fueron acondicionadas sólo con MEP y se cementaron con Variolink Esthetic LC. Al año y medio las restauraciones se observaron indemnes, manteniendo un buen ajuste marginal y ausencia de tinciones. Conclusiones. MEP aparece como una alternativa prometedora para reemplazar al ácido fluorhídrico en la cementación de laminados vitrocerámicos.

ABSTRACT: Ultrathin glass-ceramic veneers are a conservative approach for the restorative treatment of aesthetic disorders in the anterior region. However, surface conditioning with hydrofluoric acid of the thin structures can be usually a challenging step. Therefore, the use of a self-etching ceramic primer containing ammonium polyfluoride (Monobond Etch&Prime, MEP) offers a simplified technique with a reduced risk of overetching. Here we present an 18-month follow-up of ultrathin glass-ceramic veneers conditioned with MEP only. Case. Young female patient with an aesthetic disorder in the front region. The four upper incisors were conservatively prepared for ultrathin lithium disilicate (e.maxPress) veneers. Pre-treatment of the glass-ceramics consisted only of MEP application, followed by adhesive cementation with Variolink Esthetic LC. At the 1.5-year recall, the restorations appeared undamaged, with no marginal gap or staining. Conclusions. MEP constitutes a promising alternative to hydrofluoric acid for the adhesive cementation of glass-ceramic veneers.

Research progress on bracket bonding for dental fluorosis / 口腔疾病防治

@#Bonding of brackets to dental fluorosis has always been a difficult problem for clinicians. At present, clinical research has adopted several methods to facilitate bracket bonding, including prolonging etching time, enamel microabrasion, enamel ground, using adhesion promoter and laser etching. Prolonging etching time is suitable for mild-to-moderate dental fluorosis with easy chair-side operation; however, over-etching may cause severe tooth damage. Microabrasion can be applied to mild dental fluorosis while removing pigment deposition simultaneously; however, rubber dam protection is needed. Enamel ground can improve the bond strength to all kinds of dental fluorosis at the price of removing a relatively large amount of superficial enamel. Adhesion promoters might improve the bond strength of moderate to severe dental fluorosis; however, the current results conflict with one another. This needs further verification using larger-sample clinical trials. Laser etching has no effect on improving bond strength; however, it can remove pigment without destroying tooth enamel, which is worth further modification and enhancement.