Abstract The aim of this study was to investigate the mechanical performance and the fracture behavior of endocrown restorations prepared using distinct restorative materials. A total of 42 sound molars with similar crown size and shape were cut at 2 mm above the cementoenamel junction and endodontically treated. They were categorized according to the restorative material used to fabricate endocrown restorations (n=7), namely, conventional composite (Filtek™ Z350 XT), bulk fill composite (Filtek™ Bulk Fill), conventional composite modeled using resin adhesives (SBMP: Scotchbond™ Multipurpose Adhesive; or SBU: Scotchbond™ Universal Adhesive), and IPS e.max lithium disilicate (Ivoclar Vivadent; positive control). Unprepared sound teeth were used as negative control. All endocrowns were bonded using a self-adhesive cement (Rely-X™ U200). The teeth were submitted to fatigue (Byocycle) and fracture (EMIC DL500) testing. Load-to-fracture (in N) and work-of-fracture (Wf, in J/m2) values were analyzed by ANOVA (p < 0.05). The endocrowns did not fracture or de-bond upon fatigue, showing similar load-to-fracture and work-of-fracture values, regardless of the restorative material (p > 0.05). The endocrowns fabricated by combining Z350 and SBMP had the least harsh fractures, in contrast to endocrowns prepared using Z350 only, which exhibited an equilibrium between repairable and irrepairable fractures. The e.max endocrowns exhibited more aggressive failures (root fracture) than other groups, resulting in higher rates of irrepairable fractures. In conclusion, dental practitioners may satisfactorily restore severely damaged nonvital teeth using the endocrown technique. Composite endocrowns prepared using resin adhesive as modeler liquid or using bulk fill material may result in less aggressive failures, thus providing a new material perspective for endocrown restorations.

Resumo O objetivo neste estudo foi sintetizar e avaliar as propriedades físico-químicas de um novo derivado do salicilato em cimentos endodônticos experimentais à base de cálcio. Dois derivados de salicilato foram sintetizados por meio de uma reação de trans esterificação do salicilato de metila com dois diferentes alcoóis (1,3-butilenoglicol dissalicilato-BD e pentaeritritol tetrassalicilato-PT) na proporção molar de 1: 3 e 1:6, respectivamente. Os produtos (BD e PT), foram caracterizados por espectroscopia infravermelho transformada de Fourier (FTIR) e espectroscopia de ressonância magnética nuclear (RMN). Os cimentos experimentais à base de cálcio foram preparados com a mesma pasta catalisadora (60% de MTA, 39% de N-etil o/p toluenosulfonamida e 1% de dióxido de titânio) e quatro concentrações diferentes de BD e PT nas pastas base (40/0 - controle, 35/5, 30/10 e 20/20) com 60% de óxido de bismuto. Os cimentos foram avaliados quanto ao tempo de endurecimento, à solubilidade (24 h, 7, 14 e 28 dias), resistência à tração diametral e ao módulo de elasticidade. Os dados foram analisados por ANOVA um ou dois fatores e as médias comparadas pelo teste de Tukey (p<0,05). A adição de PT reduziu o tempo de endurecimento dos materiais testados. Após 24 horas os cimentos 40/0 e 35/5 apresentaram maior solubilidade que os demais e após 14 e 28 dias o cimento 20/20 foi o que apresentou menor solubilidade (p<0,05). Após 7 dias o grupo 20/20 estabilizou a sua solubilidade. O cimento 40/0 apresentou os maiores valores e o cimento 20/20 apresentou os menores valores de resistência à tração diametral e módulo de elasticidade (p<0,05). A adição de PT a cimentos à base de cálcio possibilita benefícios ao tempo de presa e solubilidade.

Abstract The aim of this study was to synthesize and evaluate physicochemical properties of a new salicylate derivative in experimental calcium-based root canal sealers. Two salicylate derivatives were synthesized for the transesterification reaction of methyl salicylate with two different alcohols (1,3-butylenoglicol disalicylate-BD and pentaerythritol tetrasalicylate -PT) in molar ratio 1:3 and 1:6, respectively. The products (BD and PT), were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance spectroscopy (RMN). Calcium-based experimental sealers were prepared with the same catalyst paste (60% of MTA, 39% of n-ethyl-o-toluenesulfonamide, and 1% titanium dioxide) and four different concentrations of BD and PT in the base pastes (40/0 - control, 35/5, 30/10 and 20/20) with 60% of bismuth oxide. The experimental sealers were evaluated for setting time, solubility (24 h, 7, 14 and 30 days), diametral tensile strength and Young’s Modulus. Data were analyzed by one- or two-way ANOVA with Tukey’s test (p<0.05). The addition of PT reduced the materials setting time. After 24 h the sealer 40/0 and 35/5 had higher solubility, and after 14 and 28 days the sealer 20/20 showed the lowest solubility (p<0.05). After 7 days the sealer 20/20 stabilized its solubility. The sealer 40/0 presented the highest values and the 20/20 presented the lowest values of diametral tensile strength and Young’s modulus (p<0.05). The addition of PT to calcium-based root canal sealers provides benefits to the setting time and solubility.

Abstract The aim of this study is to evaluate the influence of modeling liquids on the translucency and color shade of resin composites (RCs) after one year of storage. RC specimens were prepared using either a conventional insertion technique (control; without modeling liquid) or a restorative dental modeling insertion technique (RDMIT) with dental adhesives as modeling liquids (Scotchbond™ Multi-Purpose [SBMP; 3M ESPE] or Adper™ Single Bond 2 [SB; 3M ESPE]). The initial colors of the specimens were obtained with a digital spectrophotometer and the CIEL*a*b* color system, after which specimens were stored (37°C) in distilled water or red wine for 12 months. Color measurements were reassessed after 6 and 12 months of storage, and scanning electron microscopy was performed after 12 months. Translucency and color change (ΔE*) were calculated and analyzed using ANOVA and Tukey’s test (α = 5%). RC samples prepared via RDMIT showed a translucency similar to that of control samples. ΔE* was also less intense for RCs containing SBMP than for RCs containing SB. Specimens stored in wine showed a clear pattern of degradation, especially in the control group, and surface degradation seemed to be less intense for specimens prepared with SBMP and SB than for specimens without. Specimens stored in water did not show clear evidence of surface degradation. RDMIT appears to be an interesting approach to reduce ΔE* in RCs over time without negative effects on the translucency of the material. However, the modeling liquid should feature a hydrophobic composition, similar to that used in the SBMP group, the achieve the best results.

Abstract Modeling liquids/resins have been used to build up resin composite (RC) restorations, although there is a lack of information regarding their effects on the color stability of the latter. Therefore, the purpose of the present study was to evaluate the effects of the presence of modeling liquid between layers of RC and the finishing/polishing state of the material on color change in specimens exposed to red wine staining over time. Specimens were prepared by placing four increments (±0.5 mm thick) of RC (Filtek™ Z350 XT, 3M ESPE) into molds; half of which were prepared by applying modeling liquid (Scotchbond™ Multi-Purpose™ Adhesive, SBMP, 3M ESPE) between the layers of RC, whereas the other half were prepared without SBMP (control). Light-activation was performed after application of the final RC layer using a light-emitting diode (Radii, SDI) curing unit with an irradiance of 900 mW/cm2 for 20 s. Each group was divided according to the surface finishing protocol (n = 7): nothing (non-polished) or polishing with Sof-Lex™/diamond paste (polished). Initial colors of the specimens were evaluated with a digital spectrophotometer and the CIEL*a*b* color system. The specimens were stored in wine (37°C) for 12 months, and the color measurements were reassessed after 4, 6, and 12 months of storage. Scanning electron microscopy (SEM) analysis was performed at the end. Data were analyzed using ANOVA and Tukey’s test (α = 5%). The presence of SBMP resulted in lower overall color change of the RC as compared with the control. The non-polished specimens exhibited a significantly higher color change than the polished specimens. SEM images corroborated the previous findings. In summary, the use of modeling liquid between layers of RC shows potential for application to reduce or delay the staining process of RC over time. Moreover, polishing is essential to provide increased color stability of the RC restoration.

The aims of this study were to evaluate the effect of immediate and delayed resin cement application on the microtensile bond strength of indirect composite resin restorations and, to evaluate adhesive strategies (for regular resin cement or humidity parameters for self-adhesive resin cement). Forty-five enamel/dentin discs (0.5 mm height and 10 mm of diameter) obtained from bovine teeth were divided into nine groups (n = 5). For regular cement, the variation factors were cementation technique at three levels (immediate cementation, 5 or 30 min after adhesive system application); and type of adhesive system at two levels (three- or two-step). For self-adhesive cement, the dentin moisture was the source of variation at three levels (normal, dry, or wet cementation). The specimens were submitted to microtensile bond strength (μTBS) testing using a universal testing machine. Data were analyzed by ANOVA, Tukey’s test, and linear regression. Regular cement and three-step etch-and-rinse adhesive system showed the highest values of bond strength (25.21 MPa–30 min of delay). Only for this condition, three-step adhesive showed higher bond strength than the two-step adhesive. Nevertheless, the linear regression showed that irrespective of the strategy, the use of the two-step approach when compared with three-step adhesive system decreased μTBS (p < 0.001). The failure analysis showed predominant adhesive failures for all tested groups. All groups had comparable values of bond strength to bovine dentin when the same materials were used, even in suboptimal clinical conditions.

A busca da excelência estética na odontologia atual exige, por parte do cirurgião-dentista, o aprimoramento de seus conhecimentos e técnicas para a confecção de restaurações em dentes anteriores. Em razão da alta incidência e prevalência de fraturas nesta região dentária, o desafio de mimetizar as propriedades e características ópticas da estrutura dental em pacientes jovens (entre 6 e 15 anos) torna-se um desafio. O presente caso clínico relata a restauração minimamente invasiva, sem utilização de bisel, na superfície dentária de duas classes IV. Após a constatação de fratura nos elementos 11 e 21 do paciente com 10 anos, realizou-se o ensaio restaurador do mesmo, com posterior moldagem e enceramento diagnóstico. A partir da confecção do guia de silicone, confeccionaram-se as restaurações através da técnica da muralha e posteriormente foi realizada a estratificação de cores mediante o uso de diferentes tipos de resina composta. Finalmente, realizaram-se os procedimentos de acabamento e polimento.

The pursuit of esthetic excellence in dentistry today requires dental practitioners to enhance their knowledge and technique in restorations of the anterior teeth. Due to the high incidence and prevalence of fractures in this dental area, mimicking the optical properties and characteristics of the dental structure in young patients (aged 6 to 15 years) is a major challenge. This case report describes the minimally invasive, non-beveled restoration of two fractured anterior teeth (class IV). After diagnosing fractures of teeth 11 and 21 in a 10-year-old patient, a composite mock-up was performed, followed by a diagnostic wax-up. With the aid of a silicon guide, the restorations were prepared without beveling the enamel surface. We performed color stratification by using different types of composite resins. Finally, finishing and polishing procedures were carried out.

AIM: To evaluate the immediate microtensile bond strength (µTBS) of three two-step etch-and-rinse adhesive systems applied under different dentin surface moisture conditions. METHODS: Class V cavities were prepared in seventy-two bovine incisors. Each tooth was randomly allocated into three groups, according to the adhesive system used: Single Bond 2 (SB), Prime & Bond 2.1 (PB) and XP Bond (XPB). Each group was divided in three subgroups, according to the dentin moisture condition: over-wet, moist and dry (n=8). For the moist subgroups the adhesive was applied as to the manufacturer's instructions; for the over-wet ones, without drying the cavity after the rinsing procedure; and for the dry subgroups, drying the surface for 20 s. The teeth were restored with Filtek Z-250 and stored in distilled water (24 h); next, each restoration was sectioned in beam-shaped specimens which were stored for 24 h at 37 °C. Each specimen was submitted to µTBS test (EMIC), and data were analyzed using two-way ANOVA and Tukey test (p<0.05). RESULTS: There was a statistically significant interaction between the adhesive system type and the dentin surface moisture condition (p=0.003). SB and XPB presented higher bond strength in the moist dentin condition, and PB showed high µTBS values in the dry substrate. CONCLUSIONS: The moisture condition influenced the bond strength between the adhesives and dentin. SB performed better in the moist condition, whereas PB and XPB showed satisfactory bond strength in the moist and in the dry substrates. The over-wet dentin condition only impaired bond strength to SB and XPB.