The Influence on Fracture Resistance of Different Composite Resins and Prefabricated Posts to Restore Endodontically Treated Teeth.

Recent formulations of resin-based composites have incorporated different combinations of materials. However, the mechanical and bonding behavior of these materials with intraradicular posts are unclear. This study aimed to evaluate the effect of light-cure and dual-cure resin composite posts on the fracture resistance of endodontically-treated teeth. Materials and Methods: Ninety extracted human upper canines were selected and randomly divided into nine groups (n=10): (G1) endodontically treated teeth without endodontic posts; (G2) glass-fiber post cemented with glass-ionomer cement; (G3) endodontic post by dual-cure composite resin (Rebilda DC); (G4) endodontic post by dual-cure composite resin (Cosmecore); (G5) endodontic post by dual-cure composite resin (Bis-Core); (G6) endodontic post by light-cure composite resin; (G7) glass-fiber post customized with flowable composite resin; (G8) glass-fiber post cemented with light-cure composite resin; (G9) glass-fiber post cemented with self-adhesive resin cement. After the post insertion, all specimens were subjected to mechanical (250,000 cycles) and thermocycling (6000 cycles, 5 °C/55 °C) and immediate loading at 45 degrees in a universal testing machine until fracture. The data were analyzed by one-way ANOVA and multiple comparisons using the Fisher LSD Method (p < 0 05). Results: The mean failure loads (±SD) for the groups ranged from 100.7 ± 22.6 N to 221.9 ± 48.9 N. The G1 group (without endodontic posts) had a higher fracture strength than all experimental groups (p < 0.001). Conclusions: Within the limitations, the light- and dual-cure post technique did not present lower fracture resistance values as compared to the conventional glass-fiber post.

Analysis of microleakage and marginal gap presented by new polymeric systems in class V restorations: An in vitro study.

OBJECTIVE: Evaluating the contraction of polymerization effect of silorane-based composite on dental interface in enamel. MATERIALS AND METHODS: Eighty class V cavities were confectioned in forty extracted molar teeth and restored with different combinations of resinous-based and bond system. They were divided into the following groups: (G1) three-step etch-and-rinse adhesive system and methacrylate-based resin, (G2) two-step etch-and-rinse adhesive system and methacrylate-based resin, (G3) Filtek P-90 self-conditioning adhesive system and methacrylate-based resin, (G4) Adper SE Plus self-conditioning adhesive system and methacrylate-based resin, (G5) three-step etch-and-rinse adhesive system and silorane-based resin, (G6) two-step etch-and-rinse adhesive system and silorane-based resin, (G7) Filtek P-90 self-conditioning adhesive system and silorane-based resin, (G8) Adper SE Plus self-conditioning adhesive system and silorane-based resin. RESULTS: Group 7 showed lower marginal leakage when compared with all other groups (p = 0.001). CONCLUSIONS: The results allows suggesting that silorane-based resinous system is adequate to promote more satisfactory marginal sealing than any other combination, since the system is combined with its own bond system.

Push-out bond strength of fiberglass posts cemented with adhesive and self-adhesive resin cements according to the root canal surface.

Evaluating the bond strength of fiberglass posts cemented with different resin cements. MATERIALS AND METHODS: Seventy freshly extracted roots of healthy human canines were endodontically treated and prepared to receive fiberglass posts. The roots were randomly divided into seven groups: (G1) RelyX ARC, (G2) Enforce, (G3) BisCem, (G4) Duo-Link, (G5) Cement Post, (G6) Variolink II, and (G7) RelyX U200. After post cementation, the specimens were sectioned perpendicularly to the root axis using a high-speed diamond disc, totaling 340 specimens. The strength values obtained in the push-out test were submitted to two-factor ANOVA and Tukey test (p = 0.05). RESULTS: The root thirds (p = 0.001) and the type of cement (p = 0.001) influenced the bond strength values. The relation between these two factors was also significant (p = 0.011). CONCLUSIONS: The bond strength of self-adhesive resin cements was significantly higher as compared to other cements. Besides the cervical third in roots cemented with conventional cements types presented the highest bond strength values (p < 0.05).

Interdisciplinary approach using composite resin and ceramic veneers to manage an esthetic challenge.

This clinical report describes the management of an esthetic challenge in an interdisciplinary manner addressing both the soft tissue and the anterior dentition. Different restorative materials were used in an esthetic and conservative manner to provide a pleasing smile. A minimally invasive approach was adopted to manage the anterior esthetics problems, including a maxillary diastema and inadequate width-to-length tooth proportions.

The influence of titanium base abutments on peri-implant soft tissue inflammatory parameters and marginal bone loss: A randomized clinical trial.

BACKGROUND: Some techniques in implant dentistry have been suggested that may potentially alter peri-implant soft and hard tissue parameters. PURPOSE: To evaluate the peri-implant soft tissue inflammatory parameters and crestal bone loss around titanium base abutments. MATERIALS AND METHODS: Fifty two implants were placed in 21 patients and restored by single crowns. Subjects were randomly allocated into two groups: cement-retained abutment (n = 24) and titanium base (n = 28). Peri-implant probing depth, and mesial and distal marginal bone loss (MBL) were evaluated at implant loading (T1), 6 and 12 months (T2 and T3, respectively). Peri-implant bleeding-on-probing was evaluated at T2 and T3. Two-way repeated measures analysis of variance, Tukey test, Man Whitney, and Pearson correlation were performed for statistical analysis at P < .05. RESULTS: The mean difference of peri-implant MBL from implant installation to 12 months in function was 1.15 ± 0.82 mm for the cement-retained group, and 1.23 ± 0.79 mm for the titanium base group. No statistically significant difference was found between the two groups for clinical and radiographic peri-implant evaluation. CONCLUSIONS: Titanium base abutments present no negative effect on peri-implant soft tissue and MBL. When used to support single crowns, both approaches performed likewise regarding clinical and radiographic parameters.

Mechanical Degradation of Different Classes of Composite Resins Aged in Water, Air, and Oil.

A significant deterioration of the properties can drastically compromise the survival rate of restorative materials. The aim of this study was to assess flexural strength and hardness of three composite classes: hybrid composite resin (HCR), nanoparticulate composite resin (NCR), and silorane-based composite resin (SBCR). One hundred specimens were prepared for hardness testing by using a split metallic mold measuring 10 mm in diameter and 2 mm deep. Twenty specimens were prepared for each restorative material, randomly assigned for storage in air, distilled water, or mineral oil. After intervals of 24 hours, 30, 60, 90, and 120 days, hardness and flexural strength tests were initially compared in two levels: "storage medium" and "time" within each material group. A two-way analysis of variance was performed (p<0.05) on the variables "material" and "storage time" (p<0.05). The HCR showed to be stable with regard to the evaluation of flexural strength and hardness (p<0.05). A significant reduction occurs for the NCR in comparison to the other groups (p<0.05). The NCR presented the lowest values of hardness and flexural strength kept on water over time. The characteristics of material showed a strong influence on the decrease of the mechanical properties analyzed.

The surface treatment of dental ceramics: an overview

This review proposes to present some aspects of dental ceramics surface treatments, which involve the related physical and mechanical properties, as well as new technologies. The correct cementation of prosthetic restoration is essential for clinical success. However, the adhesive technique is a very recent procedure and clinicians should have a more detailed knowledge about the technique and related materials so that they can use them in their day-to-day clinical practice. Information about the the principles, indications and contraindications of adhesive cementation technique were obtained from the literature. The studies indicate that the adhesive system seems to be a valid option for fixed prosthesis cementation, since it has several advantages over conventional cementation method, especially in all-ceramic restorations. In clinical practice, the clinician should always keep in mind the characteristics of the material they are working with, so that they can select the best technique and the best cement for each clinical situation. Although more research is required in this field, there are no scientific reasons to contraindicate in routine practice.

Lentes de contato: harmonização e estética com preparos conservadores

Este trabalho teve como objetivo abordar a reabilitação do sorriso devolvendo estética e função utilizando lentes de contato dentaria com preparos conservadores, avaliando suas indicações e limitações. Para tal, foi realizada uma revisão de literatura descritiva e bibliográfica utilizando como fonte de dados para a pesquisa livros e artigos extraídos das bases Medline, Lilacs, Scielo, Pubmed. Durante o trabalho, observou-se a evolução da técnica utilizada pelo profissional juntamente com os materiais utilizados na confecção do laminado. As lentes de contato dentárias possibilitam ao dentista uma opção conservadora de utilizar materiais cerâmicos, o correto planejamento promove resultado previsíveis de sucesso, sendo assim importante o conhecimento técnico-cientifico do profissional odontológico para determinar qual material e técnica utilizar em cada caso.

Princípios básicos de oclusão ideal

A clínica odontológica engloba diversas modalidades de tratamento. Espera-se que o profissional realize os procedimentos alcançando objetivos estéticos e funcionais, com aprovação do paciente, o que representa o sucesso do tratamento. Considerando a importância dos conhecimentos acerca da oclusão estática e funcional para os procedimentos em clínica odontológica integrada, realizou-se uma revisão de literatura a fim de destacar e discutir os principais aspectos relacionados ao tema. O controle biomecânico da oclusão promove a longevidade dos tratamentos reabilitadores, minimiza a recidiva ortodôntica, impede o aparecimento de patologias oclusais, mantém restaurações estéticas em resina composta evitando possíveis fraturas e/ou desgastes. Na oclusão fisiológica há a transmissão resultante das forças oclusais para o longo eixo dos dentes posteriores, movimentos de lateralidade promovidos pelos caninos, guia anterior imediata, contatos dentários posteriores bilaterais e simultâneos, dimensão vertical de oclusão adequada e RC coincidindo com a MIH. Porém, quando ocorrem alterações, a oclusão pode tornarse patológica e os tratamentos realizados sem os devidos cuidados pouco estáveis. A má relação dos arcos dentários pode refletir em anormalidades nos dentes e/ou nos maxilares. Para corrigir aspectos ligados à oclusão há que se devolver ao paciente, por meio de reabilitação, ajustes oclusais direcionados ou movimentação ortodôntica, as características de normalidade da oclusão. Para isso, deve-se realizar abordagem única entre as especialidades, sem comprometer os aspectos estruturais e funcionais do paciente. Assim, compreende-se que uma oclusão estática e funcional correta é fundamental para qualquer tratamento odontológico, visando uma terapêutica com resultados que sejam preservados em longo prazo.

Consequências do fumo na osseointegração de implantes dentários

Os princípios de estética na Odontologia têm sido bastante defendidos nos últimos anos e a busca por um belo sorriso é cada vez maior. A implantodontia abriu novas possibilidades para a reabilitação oral, seja em pacientes edentulos parciais ou totais. Em caso de situações satisfatórias está se tornando a primeira opção para a reposição dos dentes perdidos, devido as suas inúmeras vantagens, tais como manutenção do osso alveolar, melhora na função mastigatória e fonética. Observa-se, através da literatura, que o fumo afeta a circulação rápida e eficiente, requisitos básicos para o sucesso do processo da osseointegração e do reparo ósseo.

Resistência à fratura de dentes reforçados com pinos pré-fabricados: revisão de literatura

Este estudo objetiva apresentar uma revisão de literatura sobre a resistência à fratura de dentes reforçados com pinos pré-fabricados, com ênfase nos principais fatores que contribuem para que o tratamento seja cada vez mais efetivo. Neste cenário, a reconstrução de dentes tratados endonticamente por meio dos sistemas de pinos pré-fabricados tem sido muito utilizada. Trata-se de procedimentos que têm apresentado resultados satisfatórios, aumentando a longevidade dos elementos dentários tratados endodonticamente, quando conciliados a correta indicação, qualidade dos materiais para cimentação e técnica. Destaca-se que diante da diversidade dos pinos pré-fabricados à disposição no mercado, a situação clínica deve ser estudada minuciosamente, considerando as especificidades de cada caso no momento da escolha dos pinos, para que reforcem os dentes evitando fratura. Outro fato importante, é que mais estudos se fazem necessário sobre os sistemas de pinos pré-fabricados, com vista ao sucesso clínico e longevidade do tratamento.

Levantamento de seio maxilar: uma comparação de técnicas

A utilização de implantes na reabilitação oral tem sido bastante utilizada desde a década de 1980, esse tipo de reabilitação requer uma quantidade óssea suficiente para estabilização primaria do implante. Em situações clinicas onde a quantidade óssea seja insuficiente, faz-se necessária cirurgia de enxertia para reposição desse tecido. Nessa mesma década, Tatum introduziu duas técnicas para levantamento de seio maxilar: uma traumática via janela lateral e uma atraumática através da crista. Algumas variações dessas técnicas foram descritas e novas técnicas sugeridas. Nessa revisão o objetivo foi identificar e comparar as principais técnicas de levantamento de seio maxilar, podendo concluir que a técnica traumática descrita por Tatum e a atraumática preconizada por Summers tem sua eficácia comprovada por vários autores, entretanto as outras modificações realizadas necessitam de mais estudos para comprovar sua eficácia.

Confiabilidade das medidas da face na escolha da largura dos dentes antero-superiores

Quando dentes anteriores são perdidos a substituição artificial é necessária. Um dos maiores objetivos para os profissionais de Odontologia é produzir próteses que desafiam a sua detecção. Restabelecer uma adequada dimensão mésio-distal dos dentes anteriores superiores é talvez o maior desafio e a maior dificuldade encontrada pelos cirurgiões dentistas principalmente frente à falta de registros prévios à extração. Nesse contexto o presente trabalho, através de uma revisão de literatura, avaliou a confiabilidade das medidas faciais, bem como da proporção áurea para a seleção adequada da largura dos dentes anteriores superiores. Através desse estudo pode-se observar que a proporção áurea não é encontrada na maioria da população bem como a maior parte das técnicas que utilizam referências anatômicas faciais não devem ser usadas como um fator preditivo para a seleção dos dentes anteriores superiores, porém podem ser usadas como um guia, pois podem ser importantes ferramentas na reabilitação de um sorriso quando não há referências para o planejamento. Parece serem necessários mais estudos para procurar as causas desses métodos não serem encontrados em uma parcela significativa da população.

Utilização de pinos intraradiculares

A restauração ideal de um dente compreende devolver a função, a estética e a preservação do remanescente dentário, contudo, um sistema retentor que atenda às necessidades endodônticas e proporcione uma adesão adequada é um dos maiores desafios da odontologia restauradora. Há um aumento do uso clínico de pinos de fibra de carbono e de vidro, pois além de não sofrerem corrosão, permitem um preparo conservador do tecido dental e apresentam um bom resultado estético. Além disso, se comparado com os núcleos metálicos fundidos, esses sistemas de pinos intra-radiculares de fibra diminuem o tempo clínico e não precisam do laboratório de prótese para a fabricação. Em dentes extensamente destruídos a restauração convencional tem se mostrado insatisfatórias quando comparadas a próteses de coroa total, nesses casos faz-se necessário algum tipo de retenção intra-canal como pinos e núcleos com cimentação de coroa artificial. O sistema de pinos-núcleos fundidos metálicos foram os mais populares sendo considerado "padrão ouro", devido aos percentuais de sucesso superior. São considerados ideais pela resistência e versatilidade. Os pinos pré-fabricados metálicos ou de fibra, tanto cônicos como paralelos oferecem boas retenção para restauração coronária, porém os paralelos já estão em desuso. Os pinos de fibra de vidro, por serem um tanto frágeis são recomendados em casos com mais de 50% de remanescente, quantidade recomendada também para pinos cerâmicos. Também em relação ao uso de pinos pré-fabricados, ressaltam que o diâmetro do conduto e do canal deve ser compatível, já que a dentina remanescente não deve ser diminuída a ponto de reduzir a resistência da raiz. Definitivamente deve-se considerar a quantidade de estrutura mineralizada e a possibilidade de abraçamento cervical de pelo menos 2mm cervical ao núcleo. Este efeito de abraçamento que muitos trabalhos sugerem aumenta a resistência do remanescente, preserva a integridade do selamento marginal e reduz o estresse na junção cemento núcleo. Sendo assim, todos e qualquer sistema podem apresentar ótimos resultados, desde que usados conforme sua indicação e bom senso em cada caso, respeitado comprimento e diâmetro ideais conservando ao máximo a estrutura dentária.

State of the Art of Dental Adhesive Systems.

BACKGROUND: The large dependence on a dental substrate type to bond strength has leveraged the research on materials and techniques that perform different clinical behavior, promoting a stable bonding over time. Bonding to tooth structure has different clinical behaviors and is dependent on several factors. OBJECTIVE: The aim of this paper is to reflect on the state of the art of adhesive systems after the emergence of Buonocore's experiments in current days. METHODS: An electronic search was conducted on PubMed databases and supplemented with a manual study of relevant references. RESULTS: The choice of the ideal adhesive system remains under discussion, housing a range of studies that highlight its potential characteristics, suggesting techniques that enable improvement to boost clinical outcomes. CONCLUSION: It is important to know all different types of adhesive systems, as well as their indications and limitations. An attentive consideration of several factors is crucial to achieve clinical success on the restorative procedures.

Effect of saliva contamination on cementation of orthodontic brackets using different adhesive systems.

BACKGROUND: The enamel condition and the quality of surface are points that need to be considered for achieving optimal efficiency in the treatment with orthodontic brackets. The aim of this study was to assess the immediate bond strength of metallic brackets cemented to dental. MATERIAL AND METHODS: Forty human premolars were double-sectioned, placed in PVC matrices and randomly divided into 10 groups (n=8). They received artificial saliva contamination before or after the application of adhesive systems, except for the control groups. The metallic brackets were cemented using two orthodontic cements (Transbond™ Plus Color Change, 3M Unitek e Transbond™ XT Light, 3M Unitek). The specimens were subjected to mechanical shear bond strength testing and classified according to the fracture pattern. The results were analyzed using a two-way ANOVA and Tukey's test for multiple comparisons (p<0.05). RESULTS: ANOVA analysis showed statistically significant differences between the groups (p=0.01). The Tukey's multiple comparison test indicated statistically significant difference between G6 and G7 groups (p<0.05). A high prevalence of adhesive failure in the groups receiving the hydrophobic adhesive system. CONCLUSIONS: The saliva contamination prior to the application of a hydrophobic simplified conventional adhesive system was responsible for decreasing the immediate bond strength values of brackets cemented on the dental enamel. Key words:Bonding, orthodontic brackets, shear bond strength, saliva, adhesive systems.

The Effect of Lithium Disilicate Opacity on Polymerization of a Dual-Cured Resin Cement.

The aim of this study was to evaluate the influence of different levels of opacity of the lithium disilicate framework upon polymerization of dual-cured resin cement. Four ceramic discs were used, one for each opacity framework covered by their respective ceramic veneering, and a cement group without a ceramic cover. The degree of conversion for each resin cement was estimated using the Knoop microhardness test. The group with the highest opacity showed the lowest hardness score at baseline. The study concluded that the opacity level of lithium disilicate framework could influence the degree of polymerization of a dual-cured resin cement.

Bond strength of adhesive resin cement with different adhesive systems.

BACKGROUND: To assess the immediate bond strength of a dual-cure adhesive resin cement to the hybridized dentin with different bonding systems. MATERIAL AND METHODS: Fifty-six healthy human molars were randomly divided into 7 groups (n=8). After 3 longitudinal sections, the central cuts were included in PVC matrix and were submitted to dentin hybridization according to the groups: G1 - etch & rinse system with 3-step (Apder™ Scotchbond™ Multi-Purpose, 3M ESPE), G2 - etch & rinse system with 3-step (Optibond™ FL, Kerr), G3 - etch & rinse system with 3-step (All-Bond 3®, Bisco), G4 - etch & rinse simplified system (Adper™ Single Bond 2, 3M ESPE), G5 - self-etching system with one step (Bond Force, Tokuyama), G6 - universal system in moist dentin (Single Bond Universal, 3M ESPE), G7 - universal system in dry dentin (Single Bond Universal, 3M ESPE). Then all groups received the cementing of a self-adhesive resin cement cylinder (Duo-link, Bisco) made from a polypropylene matrix. In the evaluation of bond strength, the samples were subjected to the microshear test and evaluated according to the fracture pattern by optical microscopy. RESULTS: The Kruskal-Wallis test suggests a statistically significant difference between groups (p=0,039), and Tukey for multiple comparisons, indicating a statistically significant difference between G3 and G4 (p<0.05). It was verified high prevalence of adhesive failures, followed by mixed failure and cohesive in dentin. CONCLUSIONS: The technique and the system used to dentin hybridization are able to affect the immediate bond strength of resin cement dual adhesive. Key words:Adhesion, adhesive resin cement, adhesive systems, microshear.

Does hybridized dentin affect bond strength of self-adhesive resin cement?

BACKGROUND: Evaluate the influence of different hybridization bonding techniques of a self-adhesive resin cement. MATERIAL AND METHODS: 30 human health molars were divided into six groups (n=10). The specimens received three longitudinal sections, allowing insertion of central cuts in PVC matrices. Each group received a different dentin pretreatment according to the manufacturer's recommendations, except the control group (G1), as follows. G2 - a 3-step total-etch adhesive system (Optibond™ FL, Kerr); G3 - a 3-step total-etch adhesive system (Adper™ Scotchbond™ Multi-Purpose, 3M ESPE); G4 - a 2-step total-etch adhesive system (Adper™ Single Bond 2, 3M ESPE); G5 - a single-step self-etching system (Bond Force, Tokuyama); and G6 - universal bonding system (Single Bond Universal, 3M ESPE). Then, cylinders made of self-adhesive resin cement with polypropylene matrix was cemented in all groups (RelyX U200, 3M ESPE). Bond strength was assessed by submitting the specimens to micro-shear test and was characterized according to the fracture pattern observed through optical microscopy. RESULTS: The results were submitted to the Kruskal-Wallis test, which indicated a statistically significant difference between the groups (p=0.04), and Tukey's multiple comparisons, which indicated a statistically significant difference between G1 and G3 (p<0.05). The microscopic analysis revealed a high prevalence of adhesive failures, followed by mixed fractures, and cohesive failures in the dentin. CONCLUSIONS: The use of a previous dentin hybridization protocol is able to increase adhesive bonding resistance of self-adhesive resin cement, especially when used Adper™ Scotchbond™ Multi-Purpose system. Key words:Bonding, self-adhesive resin cement, adhesive systems, microshear.

Prevalence of physical inactivity and its association on oral conditions in adolescents.

BACKGROUND: The Brazilian population presents an ever-increasing number of sedentary people with poor oral health issues, including children and adolescents. Both physical inactivity and poor oral health have shown associations with various systemic diseases. OBJECTIVE: The aim of this study was to verify the association between physical inactivity and oral health conditions. SUBJECTS: Three hundred and fifty-three adolescents (mean age 13 and 17 years). METHODS: An epidemiological cross-sectional study. Assessment of the presence of caries was made by using the decayed, missing, filled (DMF) index. Gingival bleeding and quality of oral hygiene were also examined to evaluate the oral conditions. The International Physical Activity Questionnaire (PAQ-C) was used to assess physical activity. The confidence parameter was set at p=0.05. RESULTS: The results of this study showed that 74.3% were sedentary adolescents, the great majority of whom were girls (86.4%, p=0.001). There was a positive association between sedentary lifestyle and tooth decay (p=0.001), dental plaque (p=0.009), and time spent watching television (p=0.001). CONCLUSION: This study concluded that there was a positive association between physical inactivity and poor oral health.