New material perspective for endocrown restorations: effects on mechanical performance and fracture behavior

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.

Prevotella intermedia: uma breve revisão / Prevotella intermedia: A brief review

Prevotella intermedia é um microrganismo anaeróbio Gram negativo, considerado um dos agentes etiológicos de doenças periodontais. Tendo em vista que o biofilme subgengival é um dos seus principais habitats, qualquer quebra na homeostase do meio pode favorecer seu desenvolvimento e consequente dano aos tecidos atingidos. Diversas pesquisas vêm sendo realizadas a fim de identificar o papel deste microrganismo nas doenças periodontais. Assim, este trabalho teve por objetivo revisar a literatura para coletar informações sobre as características e efeitos de Prevotella intermedia no contexto saúde-doença periodontal. A busca foi realizada nas bases de dados PubMed e Lilacs, bem como através de uma busca aleatória. De um total de 47 artigos incluídos, alguns principais resultados puderam ser destacados: Prevotella intermedia está fortemente associada ao quadro de doenças periodontais e suas características favorecem o acometimento e intensificação de doenças diversas. Além disso, este microrganismo é capaz de produzir pigmentos e uma variedade de enzimas as quais favorecem danos aos tecidos periodontais. Existem várias características que aumentam a patogenicidade e virulência deste microrganismo, como por exemplos a sua cápsula polissacarídica, a presença de enzimas protetoras contra o oxigênio, a presença e produção de proteases, além da estimulação de fatores de crescimento no hospedeiro. Não há consenso na literatura acerca da relação de causa-efeito entre presença de Prevotella intermedia e diabetes. Contudo, este microrganismo parece estar envolvido no quadro de pacientes HIV positivo. Por fim, é importante salientar que Prevotella intermedia pode adquirir resistência a alguns tipos de antibióticos, e, por isso, o seu controle é um desafio à clínica atual...

Prevotella intermedia is a Gram negative anaerobic microorganism, considered one of the etiologic agents of periodontal diseases. Taking into account that the subgingival biofilm is its major habitat, any break of the environment homeostasis may lead to the development of the microorganism and consequent damage to the surrounding tissues. Several researches have been conducted in order to identify the role of this microorganism in the periodontal diseases. Thus, this study aimed to review the literature in an attempt to collect information about the characteristics and effects of Prevotella intermedia in the periodontal healthdisease context. The search was performed in the PubMed and Lilacs databases, as well as under a random search. From a total of 47 included articles, some major results could be drawn: Prevotella intermedia is strongly related to the occurrence of periodontal diseases, and its characteristics lead to the incidence of several diseases. Moreover, this microorganism is able to produce pigments and a variety of enzymes, which potentiate the damage of periodontal tissues. There are several characteristics that increase the pathogenicity and virulence of this microorganism, including the polyssacharidic capsule, the presence of protective enzymes against oxygen, the presence and production of proteases, as well as the stimulation of grow factors in the host. There is no consensus in the literature regarding the cause-effect relationship between the presence of Prevotella intermedia and diabetes. However, this microorganism seems to be involved in the occurrence of HIV-positive people. Lastly, it is worth to mention that Prevotella intermedia may acquire strength to some antibiotic types, and, therefore, its control is a challenge to the current clinic...

Conservative dentistry: non-beveled esthetic restorations in anterior teeth / Odontologia conservadora: restaurações estéticas sem bisel em dentes anteriores

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.

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.

Influence of surface moisture condition on the bond strength to dentin of etch-and-rinse adhesive systems

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...