Efecto del tratamiento de la morfología oclusal con materiales para restauraciones preventivas / Effect of treating occlusal morphology with materials for preventive restorations

Introducción: las fosas y fisuras son áreas formadas por delgadas irregularidades de la capa del esmalte de la superficie oclusal. La compleja morfología en dientes posteriores es un determinante biológico asociado al desarrollo de caries. Objetivo: evaluar el efecto de diversas formas de tratar la morfología oclusal en la adaptación y penetración de materiales utilizados en restauraciones preventivas. Material y métodos: diseño experimental e in vitro. Sesenta terceros molares fueron distribuidos aleatoriamente en dos grupos: surco sin ameloplastia y con ameloplastia; además, contaban con acondicionamiento del esmalte que se subdividió en tres subgrupos: 1) sellador de fosas y fisuras, 2) adhesivo/sellador de fosas y fisuras y 3) adhesivo/ resina Flow. Resultados: los subgrupos adhesivo/sellador y adhesivo/ Flow alcanzaron mayores valores de adaptación íntima a las paredes del surco. Las diferencias fueron significativas entre los materiales (p = 0.0009). Las mayores zonas de desadaptación resultaron para el sellador sin y con ameloplastia. La penetración de los materiales fue mayor en los surcos con ameloplastia. En los surcos tratados con ameloplastia, el adhesivo/Flow reveló el mayor porcentaje de penetración y la mejor adaptación a las paredes del surco. Conclusiones: la penetración del material está positivamente correlacionada con la profundidad del surco. El sellador con y sin ameloplastia mostró pobre adaptación a las paredes del surco (AU)

Introduction: pits and fissures are areas formed by fine irregularities in the enamel layer of the occlusal surface. The complex morphology in posterior teeth are biological determinants associated with the development of caries. Objective: to evaluate the effect of various ways of treating occlusal morphology on the adaptation and penetration of materials used in preventive restorations. Material and methods: experimental design, in vitro. Sixty third molars were randomly distributed into two groups: groove without ameloplasty and with ameloplasty, with enamel conditioning with three subgroups: 1) pit and fissure sealer, 2) adhesive/pit and fissure sealer, 3) adhesive/resin flow. Results: the adhesive/sealant and adhesive/flow subgroups reached higher values of intimate adaptation to the furrow walls. The differences were significant between the materials (p = 0.0009). The largest areas of maladjustment were found for the sealant without and with ameloplasty. The penetration of the materials was greater in the grooves with ameloplasty. In the grooves treated with ameloplasty, the adhesive/flow revealed the highest percentage of penetration and the best adaptation to the walls of the groove. Conclusions: the penetration of the material is positively correlated with the depth of the furrow. The sealant with and without ameloplasty showed poor adaptation to the sulcus walls (AU)

Bond strength of composite resin/universal adhesive to dentin submitted to radiotherapy / Fuerza de unión de resina compuesta/adhesivo universal a dentina sometida a radioterapia

Aim: To evaluate the bond strength of a universal adhesive system to dentin submitted to radiotherapy. Materials and Methods: Sixty extracted human teeth were divided into two groups (n = 30): without radiotherapy (control); with radiotherapy, according to the adhesive protocol (n=15): ER-etch-and-rinse (acid + Single Bond Uni-versal); SE-self-etch (Single Bond Universal). The analyzes were shear bond strength (SBS) (n=10), failure pattern (n=10) and scanning electron microscopy (n=5). Data was analyzed by a two-way ANOVA (α =0.05). Results: The radiotherapy decreased SBS of the restorative material to dentin (p<0.0001). The ER protocol provided lower bond strength values (p<0.001). The predominant type of fracture without radiotherapy was mixed (SE), cohesive to the material (ER). Both protocols presented adhesive failures with radiotherapy. Teeth had a hybrid layer and long resin tags (without radiotherapy) and few tags (with radiotherapy). Conclusions: The SE adhesive mode favors the shear bond strength of resin to dentin in teeth submitted to radiotherapy.

Objetivo: Evaluar la fuerza de adhesión de un sistema adhesivo universal a la dentina sometida a radioterapia. Materiales y Métodos: Sesenta dientes humanos extraídos se dividieron en dos grupos (n = 30): sin radioterapia (control); con radioterapia, según protocolo adhesivo (n=15): ER-grabado y enjuague (ácido + Single Bond Universal); autograbado SE (Single Bond Universal). Los análisis ejecutados fueron resistencia al cizallamiento (SBS) (n=10), patrón de falla (n=10) y microscopía electrónica de barrido (n=5). Los datos se sometieron al test de ANOVA de dos vías (α =0,05). Resultados: La radioterapia disminuyó la SBS del material restaurador a la dentina (p<0,0001). El protocolo ER proporcionó valores de fuerza de unión más bajos (p<0,001). El tipo de fractura predominante sin radioterapia fue mixta (SE), cohesiva al material (ER). Ambos protocolos presentaron fallas adhesivas con radioterapia. Los dientes tenían una capa híbrida y colas de resina largas (sin radioterapia) o pocas colas de resina (con radioterapia). Conclusión: El modo adhesivo SE favorece la resistencia al corte de la resina a la dentina en dientes sometidos a radioterapia.

Resistencia de unión al cizallamiento de diferentes agentes de fijación a aleaciones metálicas odontológicas / Shear bond strength of different bonding agents to dental metal alloys

Introducción: La fijación de las restauraciones indirectas es uno de los pasos más importantes, para conseguir una adecuada retención y sellado de la interfase entre el material restaurador y el diente. Objetivo: Evaluar la resistencia de unión al cizallamiento de diferentes agentes de fijación a dos aleaciones metálicas utilizadas en odontología. Métodos: Estudio experimental in vitro. Cien especímenes de aleaciones de metales base, 50 de níquel-cromo y 50 de níquel-cromo-titanio fueron preparados y divididos de manera aleatoria en 5 grupos. Esta división se realizó acorde con el agente de fijación utilizado: sistema autograbante de dos pasos (Clearfil SE Bond; CSB), sistema adhesivo universal (Single Bond Universal; SBU), cemento resinoso autoadhesivo (Maxcem Elite; ME), ionómero de vidrio (IV) y fosfato de zinc (ZnPO). Posteriormente a la aplicación de cada agente de fijación, los especímenes tratados fueron almacenados en agua destilada por 24 h a 37 ºC y sometidos a un ensayo de resistencia de unión al cizallamiento. Resultados: La resistencia de unión al cizallamiento fue influenciada significativamente por el tipo de agente de fijación (p = 0,002) y el tipo de aleación utilizada (p < 0,001). La resistencia de unión al cizallamiento fue mayor, al utilizar el sistema Clearfil SE Bond, seguida de Single Bond Universal; las diferencias entre Maxcem Elite y el Fosfato de zinc no fueron significativas. Finalmente, el IV no mostró adhesión a ninguna de las aleaciones metálicas utilizadas. Conclusiones: El uso de Clearfil SE Bond aumentó la resistencia de unión de los cementos resinosos a las aleaciones metálicas(AU)

Introduction: The bonding of indirect restorations is one of the most important steps, in order to achieve adequate retention and sealing of the interface between the restorative material and the tooth. Objective: To evaluate the shear bond strength of different bonding agents to two metal alloys used in dentistry. Methods: In vitro experimental study. One hundred specimens of base metal alloys, 50 nickel-chromium and 50 nickel-chromium-titanium were prepared and randomly divided into 5 groups. This division was made according to the bonding agent used: two-step self-etching system (Clearfil SE Bond; CSB), universal adhesive system (Single Bond Universal; SBU), self-adhesive resin cement (Maxcem Elite; ME), glass ionomer (IV) and zinc phosphate (ZnPO). After the application of each bonding agent, the treated specimens were stored in distilled water for 24 hr at 37 ºC and subjected to a shear bond strength test. Results: Shear bond strength was significantly influenced by the type of bonding agent (p = 0.002) and the type of alloy used (p < 0.001). Shear bond strength was highest when using the Clearfil SE Bond system, followed by Single Bond Universal; the differences between Maxcem Elite and Zinc Phosphate were not significant. Finally, IV did not show adhesion to any of the metal alloys used. Conclusions: The use of Clearfil SE Bond increased the bond strength of resinous cements to metallic alloys(AU)

Applications of collagen extrafibrillar demineralization in dentin bonding / 中华口腔医学杂志

The existing dentin bonding systems based on acid-etching technique lead to the loss of both extrafibrillar and intrafibrillar minerals from dentin collagen, causing excessive demineralization. Because resin monomers can not infiltrate the intrafibrillar spaces of demineralized collagen matrix, degradation of exposed collagen and resin hydrolysis subsequently occur within the hybrid layer, which seriously jeopardizing the longevity of resin-dentin bonding. Collagen extrafibrillar demineralization can effectively avoid the structural defects within the resin-dentin interface caused by acid-etching technique and improve the durability of resin-dentin bonding, by preserving intrafibrillar minerals and selectively demineralizing extrafibrillar dentin. The mechanism and research progress of collagen extrafibrillar demineralization in dentin bonding are reviewed in the paper.

Bottom/top hardness ratio and dentin bonding stability of conventional and bulk-fill resin composites

Aim: To evaluate the bottom/top hardness ratio (B/T) and the dentin bonding stability of conventional and bulk-fill resin composites in high c-factor preparations. Methods: Regular conventional (Tetric N-Ceram ­ TNC, and Polofil Supra ­ PFS), regular bulk-fill (Tetric N-Ceram Bulk fill ­ TBF, and Admira Fusion X-tra ­ AFX), and low viscosity bulk-fill resin composites (Tetric N-flow ­ TNF, and X-tra Base ­ XTB) were used to restore 180 dentin conical preparations. The specimens were randomly distributed in 12 groups (n = 15) according to the resin composites and storage time-points (24 h and six months) tested. After 24 h storage, all specimens were subjected to the bottom/top hardness ratio analysis. Then, the push-out bond strength test was performed in half of the specimens and the other half were maintained for six months on water storage before testing. The failure modes were analyzed in a stereomicroscopic. The data were analyzed statistically using one- and two-way ANOVA and Tukey post-test (p <0.05). Results: There were no statistically significant differences for the bottom/top hardness ratio among the resin composites (p>0.05). Regardless of the storage timepoint, regular bulk-fill resin composites showed the highest bond strength values statistically (p<0.05). Only conventional resin composites showed statistically lower bond strength values at six-month storage (p<0.05). Adhesive failures were more predominant for low-viscosity bulk-fill resin composites. Conclusion: Although the DoC was not affected by different materials tested, only bulk-fill resin composites did not present dentin bond strength loss after six-month of water storage

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.

Effect of S. mutans biofilm on the hybrid ceramic-resin cement bond strength assessed by different methods

Aim: The purpose of this study was to investigate the biofilm effect on the hybrid ceramic-resin cement bond strength (BS) by comparing two methods. Methods: Teeth were distributed into groups (n=5), according to the resin cement (Maxcem Elite-(MC) or NX3 Nexus-(NX)) and degradation method (24h or 7 days in distilled water; 7 or 30 days incubated with biofilm and 30 days in sterile media). Treated surfaces of Vita Enamic blocks (5x6x7mm) were luted to treated or no treated dentin surfaces and light-cured. After 24h, beams were obtained (1x1x10mm) and stored accordingly. The flexural bond strength (FBS) was assessed by four-point bending test. Additional beams were obtained from new teeth (n=5), stored for 24h or 7 days in distilled water, and submitted to a microtensile bond strength (µTBS) assay. Failure modes were determined by scanning electron microscopy (100X). The flexure strength of the cements (n=10) was assessed by a four-point bending test. Data were analyzed by 1 and 2-ways ANOVA, and Tukey's test (α=0.05). Results: There was no significant difference between the degradation methods for the FBS groups. For the µTBS, the significant difference was as follows: NX 7days > NX 24h > MC 7days = MC 24h. Failure mode was mainly adhesive and mixed, but with an increase of cohesive within cement and pre-failures for the MC groups assessed by µTBS. NX had better performance than MC, regardless of the method. Conclusions: The biofilm had no effect on the materials BS and FBS test was a useful method to evaluate BS of materials with poor performance

Effects of thermal cycling on bonding properties of novel low-shrinkage resin adhesive / 华西口腔医学杂志

OBJECTIVES@#The current study aimed to investigate the bonding properties of a novel low-shrinkage resin adhesive containing expanding monomer and epoxy resin monomer after thermal cycling aging treatment.@*METHODS@#Expanding monomer of 3,9-diethyl-3,9-dimethylol-1,5,7,11-tetraoxaspiro-[5,5] undecane (DDTU) as an anti-shrinkage additive and unsaturated epoxy monomer of diallyl bisphenol A diglycidyl ether (DBDE) as a coupling agent were synthesized. A blend of DDTU and DBDE at a mass ratio of 1∶1, referred to as "UE", was added into the resin matrix at the mass fraction of 20% to prepare a novel low-shrinkage resin adhesive.Then, the methacrylate resin adhesive without UE was used as the blank control group, and a commercial resin adhesive system was selected as the commercial control group. Moreover, the resin-dentin bonding and micro-leakage testing specimens were prepared for the thermal cycling aging treatment. The bonding strength was tested, the fracture modes were calculated, the bonding fracture surface was observed by scanning electron microscope (SEM), and the dye penetration was used to evaluate the tooth-restoration marginal interface micro-leakage. All the data were analyzed statistically.@*RESULTS@#After aging, the dentin bonding strength of the experimental group was (19.20±1.03) MPa without a significant decrease (P>0.05), that of the blank control group was (11.22±1.48) MPa with a significant decrease (P<0.05) and that of the commercial control group was (19.16±1.68) MPa without a significant decrease (P>0.05). The interface fracture was observed as the main fracture mode in each group after thermal cycling by SEM. The fractured bonding surfaces of the experimental group often occurred on the top of the hybrid layer, whereas those of the blank and commercial control groups mostly occurred on the bottom of the hybrid layer. Micro-leakage rating counts of specimens before and after thermal cycling were as follows: the experimental group was primarily 0 grade, thereby indicating that a relatively ideal marginal sealing effect could be achieved (P>0.05); meanwhile, the blank control group was primarily 1 grade, and the penetration depth of dye significantly increased after thermal cycling (P<0.05); the commercial control group was primarily 0 grade without statistical difference before and after thermal cycling (P>0.05), while a significant difference was observed between the commercial control group and experimental group after thermal cycling (P<0.05).@*CONCLUSIONS@#The novel low-shrinkage resin adhesive containing 20%UE exhibited excellent bonding properties even after thermal cycling aging treatment, thereby showing a promising prospect for dental application.

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.

Effects of dentinary contamination by endodontic irrigants on bonding strength of adhesive systems

This study aimed to evaluate if 2.5% sodium hypochlorite compromises the adhesion of bonding materials. The factors in the study were the irrigation solutions in two levels: 2.5% sodium hypochlorite and saline solution; and the adhesive systems used in three levels: three-step adhesive, universal adhesive, and two-step self-etch adhesive systems. The answer variable used was the microshear bond strength obtained through a universal testing machine and fracture mode. Six groups were obtained (n=10) : Etch-and-rinse/Saline (saline solution + 3-step adhesive system - Scotchbond Multipurpose, 3M ESPE); Universal/saline (saline solution + universal adhesive system ­ Prime&Bond,); Self-etch/saline (saline solution + 2-step self-etch adhesive systems - Clearfil SE Bond); Etch-and-rinse/Hypo (sodium hypochlorite 2,5% + 3-step adhesive system - Scotchbond Multiuso); Universal/Hypo (sodium hypochlorite 2,5% + universal adhesive system ­ Prime&Bond); Self-etch/Hypo (sodium hypochlorite 2,5% + 2-step self-etch adhesive system - Clearfil Se Bond). The specimens were obtained from 60 healthy bovine incisors. The crowns were separated from the roots, and the regularization of the buccal surface was performed. The groups received saline solution and 2.5% sodium hypochlorite for 30 minutes, respectively. A matrix of 1mm and 3mm oh height was stabilized by Scotch tape to obtain the resin sticks. Afterward, the bond strength test was performed in a universal testing machine at 1mm/min speed. The data were analyzed with normality Shapiro-Wilk, two-way ANOVA, and Tukey's tests (p<0.001). Etch-and-rinse and Self-etch adhesives presented the highest bond strength values after irrigation with saline solution and 2.5% sodium hypochlorite, respectively (P < 0.01). The irrigation with 2.5% sodium hypochlorite decreased the bond strength values of Etch-and-rinse and Universal (P < 0.01). On the other hand, 2.5% sodium hypochlorite improved the bond strength values of Self-etch (P < 0.01). In conclusion, 2.5% sodium hypochlorite negatively impacted the bond strength of Etch-and-rinse and Universal but improved the adhesion of Self-etch.

Comparative Study of the Shear Bond Strengths and Bracket Failure Rates of Two Orthodontic Adhesive Systems

Abstract Objective: To evaluate and compare the shear bond strengths (SBS) and bracket failure rates (BFR) of orthodontic brackets bonded with Light Cure adhesive against those bonded with Self Cure adhesive. Material and Methods: The study had in vitro and in vivo parts. In the in vitro part to determine SBS of Light Bond(LB)(R) and Rely.a.Bond(RB)(R) adhesives used in bonding brackets to 88 extracted teeth, each adhesive type was used to bond 44 brackets. The clinical study was conducted to determine the BFR of the LB(R) and RB(R) adhesives by bonding 256 teeth using each adhesive type. A standardized bonding procedure was followed in both the in vitro and in vivo parts of the study. Data were analyzed using frequency, percentage, mean, independent t-test, chi-square, and Pearson Correlation statistics. A p-value of ≤ 0.05 was considered significant. SPSS version 21.0 was used to analyze the data generated. Results: There was a significantly higher mean SBS 10.6MPa for LB(R) adhesive than the 7.0MPa of the RB(R) adhesive. In the in vivo study, (LB)(R) had a greater but not significant BFR of 9.0% than RB(R) (8.0%). No significant relationship existed between the SBS of either adhesive type (as determined in vitro) and their BFR in vivo. Conclusion: Higher SBS of LB(R) did not translate to less BFR in the clinic, nor did a lower SBS of RB(R) translate to more BFR in the clinic (AU).

Evaluation of Microleakage at the Junction Between Combined Amalgam/Composite Resin Restorations Using Different Bonding Systems in Class II Cavities

Abstract Objective: To evaluate the microleakage at the junction between amalgam-composite resin restorations using different bonding systems. Material and Methods: In this in-vitro study, standard class II cavities were prepared on 40 human maxillary premolars. The axial and gingival floor depths of the cavities were 2 mm and 1 mm below (cementoenamel junction), respectively. The samples were divided into 4 groups (n = 10). In all groups, a layer of 1-mm thick amalgam was used as a coating for the initial part of the gingival floor. In group 1, no bonding system was used for amalgam restoration. In group 2, G-Premio Bond was applied. G-Premio bond + alloy primer and single bond + alloy primer were used in group 3 and group 4, respectively. The rest of the cavities in all groups were then repaired using FiltekZ250 composite. The samples were thermocycled at 500 rpm and immersed in 1% methylene blue solution for 24 hours to allow dye penetration. Once cut, the samples were placed under a stereomicroscope (40X) to determine the microleakage rate. Data analysis was carried out using post-hoc and Chi-square tests (p<0.05). Results: The highest and lowest microleakage rate was related to groups 1 and 3, respectively. There was a significant difference between groups (1,2) and (1,3), and (1,4), and groups (2,3) (p<0.05). Conclusion: The use of alloy primer and bonding could reduce the microleakage between the two restorations (AU).

Tratamiento de la fractura corono-radicular no complicada de la corona: caso clínico / Treatment of non-complicated crown-root fracture: a clinical case

El trauma dentoalveolar se define como aquella lesión de extensión e intensidad variable y de ori- gen accidental o intencional, causada por fuerzas que actúan sobre el órgano dentario y los tejidos que lo rodean. Se puede diagnosticar a simple vista o con ayuda de la radiografía, se debe tratar sin demora para preservar la vitalidad de la pulpa, sobre todo en casos de niños y adolescentes, to- mando en cuenta la formación radicular. El trau- ma dental es motivo de urgencia por el dolor que provocan en los pacientes, la prevalencia varia del 26 al 76% de las lesiones dentales en dentición permanente (AU)

The influence of prophylaxis with amino acid glycine powder and sodium bicarbonate jet on the bond strength of dental enamel / A influência da profilaxia com aminoácido glicina em pó e jato de bicarbonato de sódio na resistência de união do esmalte dentário

Aim: To compare the influence of prophylaxis with sodium bicarbonate and amino acid glycine powder on the bond strength of bovine teeth enamel and on the properties of two adhesive systems. Methods:Thirty-six extracted bovine incisors were randomly divided into six groups (n = 6) according to the prophylactic treatment received: no prophylactic treatment (NT), sodium bicarbonate powder (SB), and glycine powder (GL). Each group was subdivided into 2 groups based on what adhesive systems were used: conventional system (A) and universal system (B). Composite resin was applied on the buccal surface of the teeth in a block measurement 8x8x6 mm. The specimens were cut to obtain beams measuring 1.0 x 1.0 mm and were subjected to microtensile bond strength tests. Results were compared using two-way ANOVA (p ≤ 0.05). Results: The GLA group obtained the highest bond strength value for the conventional adhesive (18.97 MPa), but the GLB group obtained a lower strength value than the SBB group (GLB: 21.05 MPa and SBB: 22.29 MPa) (p < 0.05). Conclusions: Cleaning of the enamel surface increases the adhesive properties of restorative materials, and the bond strength was more effective in the group that received glycine prophylaxis and the conventional adhesive system.

Objetivo:Comparar a influência da profilaxia com bicarbonato de sódio e ClinproProphy ™ na resistência de união do esmalte de dentes bovinos e nas propriedades de dois sistemas adesivos.Métodos: Trinta e seis incisivos bovinos extraídos foram divididos aleatoriamente em 6 grupos (n = 6), cada um de acordo com o tratamento profilático recebido: nenhum tratamento profilático (NT), bicarbonato de sódio em pó (SB), glicina em pó (GL). Cada grupo foi subdividido em 2 grupos com base nos sistemas adesivos utilizados: sistema convencional (A) e sistema universal (B). A resina composta foi aplicada na superfície bucal dos dentes em um bloco de 8x8x6 mm. As amostras foram cortadas para obter blocos medindo 1,0 x 1,0 mm e submetidas a testes de resistência de união por microtração. Os resultados foram comparados usando o teste two-way ANOVA (p ≤ 0,05). Resultados: O grupo GLA obteve o maior valor de resistência de união para o adesivo convencional (18,97 MPa), mas o grupo GLB obteve um valor de resistência menor que o grupo SBB (GLB: 21,05 MPa e SBB: 22,29 MPa) (p < 0,05). Conclusão: A limpeza da superfície do esmalte aumenta as propriedades adesivas dos materiais restauradores, e a resistência adesiva foi mais eficaz no grupo que recebeu profilaxia com glicina e sistema adesivo convencional.

Effect of hydroxyapatite based agents on the bonding properties of universal adhesives / 中华口腔医学杂志

Objective: To study the effect of hydroxyapatite (HA) based agents on the bonding properties of universal adhesive with different application modes, and to provide evidence for the use of adhesives after desensitization treatment. Methods: Sixty impacted third molars were extracted and selected (acquired from Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi'an Jiaotong University). Four third molars were used to prepare 1 mm thick dentin disks and treated with 1% citric acid to simulate sensitive tooth models. The dentin surfaces were observed by scanning electron microscope (SEM) after treating with no desensitization (control group), desensitized by HA based toothpaste Biorepair and Dontodent Sensitive respectively (desensitizing toothpaste A group and B group), or HA paste treatment (desensitizing paste group ) (n=2 per group). The remaining teeth were selected to expose the mid-coronal dentin and establish dentin sensitivity models. Then, the specimens were divided into 4 former groups and received corresponding treatment. Each group was randomly divided into 2 subgroups, and intermediately strong universal adhesive (G-Premio Bond) was applied on the desensitized dentin by either etch-and-rinse mode or self-etch mode. Resin-dentin slice specimens (n=4 per subgroup), microtensile specimens (n=20 per subgroup) and slice specimens (n=6 per subgroup) were prepared. The microstructure and nanoleakage of the adhesive interfaces were observed by scanning electron microscopy (SEM). The microtensile strength (bond strength) and fracture mode were tested and recorded. The water permeability of the adhesive interface was observed by laser scanning confocal microscopy (LSCM). Results: SEM showed that desensitizing toothpaste and desensitizing paste could partially or entirely occlude most of the dentin tubules. For the etch-and-rinse mode, the bond strength of specimens treated with toothpaste A [(40.98±4.60) MPa], toothpaste B [(40.89±4.64) MPa] and HA paste [(41.48±3.65) MPa] was significantly higher than that of the control group [(38.58±4.28) MPa] (F=3.89,P<0.05). There was no statistically significant difference in bond strength among the 4 subgroups for self-etch modes (F=0.48,P>0.05). After desensitization, the bond strength of the control group and desensitizing groups in the self-etch mode was significantly higher than that in the etch-and-rinse mode (P<0.05). The overall fracture modes were mixed failure and interfacial failure in the control group and desensitizing groups. SEM showed speckled silver-stained particles deposited along the bottom of the hybrid layer on the bond interface of etch-and-rinse mode, and there were few silver-stained particles deposited on the bond interface of self-etch mode. LSCM showed continuous linear penetration in the hybrid layer of etch-and-rinse mode subgroups and discontinuous linear penetration in the hybrid layer of self-etch mode subgroups. Conclusions: HA based desensitizers have no adverse effect on the bond strength of intermediately strong universal adhesive and show good bonding performance accompanied with the self-etch mode.

Effects of different concentrations of sodium hypochlorite on dentine adhesion and the recovery application of sodium erythorbate / 中南大学学报(医学版)

OBJECTIVES@#Root canal therapy is the most effective and common method for pulpitis and periapical periodontitis. During the root canal preparation, chemical irrigation plays a key role. However, sodium hypochlorite (NaOCl), the widely used irrigation fluid, may impact the bonding strength between dentin and restorative material meanwhile sterilization and dissolving. Therefore, it's important to explore the influence of NaOCl on the adhesion between dentin and restoration materials to ensure clinical efficacy. This study aims to explore the effect of NaOCl on dentine adhesion and evaluate the effect of dentine adhesion induced by sodium erythorbate (ERY), and to provide clinical guidance on dentin bonding after root canal therapy.@*METHODS@#Seventy freshly complete extracted human third molars aged 18-33 years old, without caries and restorations were selected. A diamond saw was used under running water to achieve dentine fragments which were divided into 10 groups with 14 fragments in each group: 2 control [deionized water (DW)±10% ERY] and 8 experimental groups (0.5%, 1%, 2.5%, and 5.25% NaOCl±10% ERY). The dentine specimens in the control group (treated with DW) and the experimental groups (treated with 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl) were immersed for 20 min using corresponding solutions which were renewed every 5 min. The other 5 groups were immersed in 10% ERY for 5 min after an initial washing with DW for 1 min. Then, we selected 4 dentine fragments from all 14 fragments in each group and the numbers and diameters of opening dentinal tubules were observed under scanning electron microscope (SEM). The other 10 dentine fragments from each group were used to make adhesive samples by using self-etch adhesive wand composite resin. All the above adhesive samples were sectioned perpendicular to the bonded interface into 20 slabs with a cross-sectional area of 1 mm×1 mm using a diamond saw under the cooling water, and then the morphology of 10 slabs in each group's bonding interface was observed from aspects of formation of resin tags, depth of tags in dentin, and formation of hybrid layer under SEM. The other 10 slabs of each group's microtensile bond strength and failure modes were also analyzed.@*RESULTS@#Among the 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl groups, the number and diameter of patent dentinal tubules gradually increased with the rise of concentration of NaOCl solution (all P<0.05). Among the DW, 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl groups, the number and diameter of patent dentinal tubules increased after using ERY, but without significant difference (all P>0.05). Among the DW, 0.5% NaOCl, 1% NaOCl, and 2.5% NaOCl groups, the scores of formation of resin tags under SEM gradually increased with the increase of concentration of NaOCl solution, while the score in the 5.25% NaOCl group decreased significantly compared with the score of the 2.5% NaOCl group (P<0.05). There was no significant difference between using 10% ERY groups and without using 10% ERY groups (all P>0.05). The scores of length of the tags under SEM in the 5.25% NaOCl group was significantly higher than the scores of DW, 0.5% NaOCl, and 1% NaOCl groups (all P<0.05), and it was also higher than the score of the 2.5% NaOCl group, but without significant difference (P>0.05). There was no significant difference between using 10% ERY groups and without using 10% ERY groups (P>0.05). The scores of formation of hybrid layer under SEM in the 2.5% NaOCl and 5.25% NaOCl groups significantly decreased compared with the score of the DW group (all P<0.05). There were significant differences between the 2.5% NaOCl±10% ERY groups and between the 5.25% NaOCl±10% ERY groups (all P<0.05). Microtensile bond strength was greater in the 0.5% NaOCl, 1% NaOCl, and 2.5% NaOCl groups, but lower in the 5.25% NaOCl group than that in the DW group (all P<0.05). There were significant differences between the 2.5% NaOCl±10% ERY groups and between the 5.25% NaOCl±10% ERY groups (all P<0.05). The incidence of type "Adhesive" of failure modes in the 5.25% NaOCl group was significantly higher than that in other groups (all P<0.05), while the incidence of type "Adhesive" in the 5.25% NaOCl+10% ERY group was lower than that in the 5.25% NaOCl group (P<0.05).@*CONCLUSIONS@#The bonding strength to dentine increases with the increase of NaOCl concentration when the concentration lower than 2.5%; whereas it is decreased at a higher concentration (such as 5.25%). 10% ERY has a definite recovery effect on attenuated bonding strength to 5.25% NaOCl-treated dentine.

Effect of a novel radio-frequency atmospheric-pressure glow discharge plasma jet treatment on crosslinking of dentin collagen / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effect of a noval radio-frequency atmospheric-pressure glow discharge (RF-APGD) plasma jet on crosslinking of dentin collagen.@*METHODS@#(1) Twenty intact third molars were collected. The middle dentin discs were prepared for each tooth by low-speed water-cooled Isomet saw, and then immersed in 10% (mass fraction) H3PO4 solution for 16 h to obtain fully demine-ralized dentin collagen. The twenty dentin discs were then randomly divided into five groups. The control group was untreated while the four experimental groups were treated by plasma jet with gas temperature of 4 ℃ for different times (20 s, 30 s, 40 s, and 50 s). The structure and crosslinking degree of dentin collagen were characterized by attenuated total reflection-Fourier transform infrared spectroscopy. The surface morphology of demineralized dentin was observed by scanning electron microscope, and the microstructure was observed by transmission electron microscope. (2) Fourty non-caries third molars were collected to prepare 5 g fine dentin powder, then completely demineralized with 10% H3PO4 solution. The control group was untreated, while the four experimental groups were treated by plasma jet for 20 s, 30 s, 40 s and 50 s. The crosslinking degree of each group was determined by ninhydrin colorimetric method. (3) Forty intact third molars were collected to obtain dentin strips. Only two central symmetrical dentin strips (nasty 80) were taken from each tooth and immersed in 10% H3PO4 solution for 16 h to obtain fully demineralized dentin collagen. Eighty dentine collagen fiber strips were randomly divided into five groups. The control group was untreated and the axial surfaces of dentin collagen fiber strips in the expe-rimental groups were treated with the plasma jet for 20 s, 30 s, 40 s and 50 s. The ultimate tensile strength of dentin was measured by universal mechanical machine.@*RESULTS@#(1) The surface morphology of demineralized dentin observed by scanning electron microscope showed that the network structure of collagen fibers on the surface of demineralized dentin treated with the plasma jet for 20 s, 30 s and 40 s could maintain the uncollapsed three-dimensional structure, and part of the microstructure was destroyed after plasma jet treated for 50 s. After being treated by plasma jet for 20 s, 30 s and 40 s, the three-dimensional structure was uncollapsed, and the typical periodic transverse pattern of natural type Ⅰ collagen fiber could be seen. The results of infrared spectra showed that the secondary conformation of dentin collagen fibers was the same as that of the control group after being treated with the plasma jet, and the intensity of amide band was significantly increased after being treated for 30 s and 40 s. (2) The results of ninhydrin crosslinking test showed that the crosslinking ratio of dentin collagen treated by plasma jet for 30 s and 40 s was the highest, and the difference was statistically significant (P < 0.05). (3) The results of dentin ultimate tensile strength showed that the control group was (1.67±0.24) MPa, and the plasma jet treated 20 s, 30 s, 40 s and 50 s groups were (4.21±0.15) MPa, (7.06±0.30) MPa, (7.32±0.27) MPa, and (6.87±0.17) MPa, which were significantly different from that of the control group (P < 0.05).@*CONCLUSION@#The novel RF-APGD plasma jet treatment can promote the crosslinking degree of demineralized dentin collagen and improve their ultimate tensile strength.

Effect of sodium hypochlorite in ground fluorotic enamel: Shear bond strength and surface analysis / Efecto del hipoclorito de sodio en esmalte fluorótico tallado: resistencia adhesiva al cizallamiento y análisis de la superficie

ABSTRACT: Evaluate the effect on the shear bond strength (SBS) of 5% NaOCl applied after acid etching on ground anterior teeth with fluorosis and analyze the surface with scanning electron microscopy (SEM), also compare fluorotic and healthy ground enamel by atomic force microscopy (AFM) and Vickers microhardness (VM). For the SBS test 30 anterior teeth with moderate and severe fluorosis according Dean index were selected by an examiner previously calibrated with an expert in fluorosis by using the intraclass correlation coefficient (ICC). With the help of a calibrated high speed diamond bur for veneer preparation and a parallel chamfer high speed diamond bur he vestibular face was prepared with a uniform reduction of .3 mm under water cooling. In one half of the vestibular face of the teeth the conventional adhesive procedure was carried out while in the other half was added an additional step with 5% NaOCl applied for 1 minute and washing after acid etchant. A resin post was adhered in each half and load was applied until fracture. The failure mode was evaluated and a SEM analysis was made. Posteriorly 10 samples of fluorotic and healthy ground enamel were used to measure the nanostructural characteristics by AFM (roughness average and absolute depth profile) and the VM in three operative steps (after ground, after etchant and after deproteinization). The Shapiro-Wilks and Brown-Forsythe methods were used to test the distribution of variables. The Paired Student's t-test was used to compare the differences between mean bond strength (MPa) in the two groups for SBS test. Chi- square analyzes were performed to compare the failure modes between groups. One- way ANOVA analysis and Tukey-Kramer post hoc test were used to compare groups for roughness average, absolute depth profile and Vickers microhardness. A greater SBS (32.17±4.20 MPa) and a surface more homogeneous and less contaminated were observed in the deproteinization subgruoup compared to the conventional subgroup (27.74±4.88 MPa). AFM parameters were greater in fluorosis subgroup than in healthy enamel subgroup. VM was lower in the fluorotic enamel in each operative step in comparation with healthy enamel. The use of 5% NaOCl as a deproteinizing agent after acid etchant in ground fluorotic enamel results in better adhesion, which may imply greater success in adhesive treatments. The ground surface of fluorotic enamel shows higher values of roughness and depth and lower values of VM which proves that there is a more irregular and less hard surface.

RESUMEN: Evaluar el efecto en la resistencia adhesiva al cizallamiento (SBS) de la aplicación de 5% de NAOCl después del grabado ácido en dientes anteriores fluoróticos tallados y analizar la superficie con microscopía electrónica de barrido (SEM), también comparar esmalte tallado fluorótico y sano por microscopía de fuerza atómica (AFM) y microdureza Vickers (VM). Para la prueba SBS 30 dientes anteriores con fluorosis moderada y severa de acuerdo al índice de Dean fueron seleccionados por un examinador previamente calibrado por un experto en fluorosis usando el coeficiente de correlación intraclase (ICC). La cara vestibular se preparó .3mm con la ayuda de una fresa calibrada para la preparación de carillas y una paralela con punta en chamfer de diamante a alta velocidad e irrigación. En una mitad de la superficie vestibular de los dientes se llevó a cabo el procedimiento adhesivo tradicional, mientras que en la otra mitad se incluyó un paso adicional con la aplicación de NaOCl al 5% por un minute y lavado posterior al grabado ácido. Un poste de resina fué adherido en cada mitad y se aplicó carga hasta la fractura. Se evaluó el modo de fallo y se realizó un análisis con SEM. Posteriormente se utilizaron 10 muestras de esmalte tallado fluorótico y sano para medir las características nano estructurales por medio de AFM (rugosisdad promedio y perfil de profundidad absoluta) y la VM en tres diferentes pasos operativos (posterior al tallado, posterior al grabado ácido y posterior a la desproteinización). Se utilizaron los métodos de Shapiro Wilks y Brown-Forsythe para conocer la distribución de las variables. Una T de student pareada se utilizó para comparar la diferencia entre los promedios de la fuerza de unión (MPa) entre grupos para la prueba SBS. Se llevaron a cabo análisis de chi cuadrada para comparer los modos de fallo entre los grupos. Análisis de ANOVA de una vía y Tukey-Kramer post hoc fueron utilizados para comparar los grupos para las variables rugosidad promedio, perfil de profundidad absoluta y microdureza Vickers. Se observó una mayor SBS (32,17±4,20 MPa) y una superficie más homogénea y menos contaminada en el subgrupo con desproteinización en comparación con el subgrupo convencional (27,74±4,88 MPa). Los parámetros de AFM fueron mayores en el subgrupo de fluorosis que en el subgrupo de esmalte sano. La VM fue más baja en el esmalte fluorótico en cada paso operativo en comparación con el esmalte sano. El uso de NaOCl al 5% como agente desproteinizante después del grabado ácido en el esmalte fluorótico tallado da como resultado una mejor adhesión, lo que puede implicar un mayor éxito en los tratamientos adhesivos. La superficie tallada del esmalte fluorótico muestra valores más altos de rugosidad y profundidad y valores más bajos de VM lo que prueba que existe una superficie más irregular y menos dura.

Durability of bond strength to dentin using two universal adhesives in different etching modes

Aim. To evaluate the bond durability of two universal adhesives; mild and ultra-mild in both etch-and-rinse and self-etch modes after simulated in-vitro degradation by long-term water storage or thermocycling. Methods. A total of 144 specimens were used in this study; 120 specimens (prepared from 30 teeth) for microshear bond strength testing and fracture mode assessment, and 24 specimens for scanning electron microscopic evaluation (prepared from 24 teeth). Specimens were prepared from 54 recently extracted caries free third molars and randomly divided into 12 groups, according to the adhesive treatment (All Bond or Scotchbond Universal), etching mode (etch-andrinse or self-etch) and aging method (thermocycling or water storage). Each tooth was sectioned mesio-distally into two halves exposing free dentin surface for bonding where dentin substrate 1 mm below the dentino-enamel junction was used. After adhesive application and composite build up, specimens were tested in shear mode after storing in distilled water at 37˚C for 24 hours or 1 year, or after being thermocycled between 5 and 55 °C for 10,000 cycles (n=10). Microshear bond strength (µSBS) was tested using a universal testing machine. Adhesive-dentin interface was examined using scanning electron microscope (SEM) (n=2). Data were analyzed using 3 way AN0VA and pairwise comparisons was performed using Bonferroni correction at significance level of α ≤0.05. Results. Statistical analysis revealed non-significant difference for etching mode in both adhesives (p=0.596). After aging, the bond strength was only reduced in Scotchbond Universal after one year of water storage in both modes (p<0.001). SEM evaluation revealed intact hybrid layer and longer resin tags for etch-and-rinse mode than selfetch mode of both adhesives. Conclusion. The bond strength of universal adhesives is not affected by the etching mode, however its durability was shown to be material dependent

Bond strength of selfadhesive flowable resin composites to tooth structure: a systematic review

Aim: To review the current literature regarding the bond strength of self-adhesive flowable resin composites (SAFRCs) to tooth structure, comparing the outcomes with conventional flowable resin composites (CFRCs). Methods: PubMed/Medline, EbscoHost and Scopus databases were screened (last update on November 2020) using related Medical Subject Headings (MeSH) and free terms. We included in vitro studies published in English language comparing the bond strength of SAFRCs and CFRCs to enamel and/or dentin from primary and/or permanent teeth. Results: In total, 23 articles were included. Unlike CFRCs, SAFRCs such as Vertise® Flow and Fusio™ Liquid Dentin exhibited statistically lower bond strength to enamel and dentin from permanent teeth. There were limited studies comparing the enamel bond strength of CFRCs and SAFRCs (prior phosphoric acid etching and/or adhesive system use). Also, we found few studies that evaluated the bonding effectiveness of Constic® and other SAFRCs to primary teeth. Conclusions: Current SAFRCs showed low bond strength to permanent teeth, which impedes to recommend them as a reliable alternative to CFRCs. The bonding performance of Constic® on both hard dental tissues should be evaluated on future studies. Also, more evidence assessing the bond strength of SAFRCs to primary teeth and etched enamel is needed