Influence of alveolar bone height on the biomechanical behavior of roots restored with custom-made posts-and-cores.

OBJETIVE: This study evaluated the influence of alveolar bone height and post type on compressive force resistance, fracture pattern, and stress distribution in endodontically treated teeth. MATERIALS AND METHODS: Bovine roots were endodontically treated and divided into eight groups (n = 10) according to alveolar bone height (normal alveolar bone and alveolar bone loss - 2 and 5 mm from the margin of the crown, respectively) and post type (prefabricated glass fiber post, anatomic glass fiber post, customized milled glass fiber post-and-core and customized milled polyetheretherketone (PEEK) post-and-core). Mechanical fatigue was simulated (300.000 cycles/50 N/1.2 Hz). Compression force resistance (N) was analyzed by two-way ANOVA and Tukey test (α = 0.05). Fracture patterns were described as percentages. Stress distribution was analyzed by finite element analysis. RESULTS: Significant diferences were found for alveolar bone height (P < 0.0001): normal alveolar bone groups showed higher mean values of compression force resistance compared to alveolar bone loss groups, while no significant differences were found for post type (P = 0.4551), and there was no double interaction between them (P = 0.5837). Reparable fractures were more predominant in normal alveolar bone groups, especially in the milled glass fiber and PEEK post-and-core groups. Stress distribution was similar in groups with prefabricated glass fiber posts and milled PEEK posts-and-cores, and the alveolar bone loss condition significantly increased stress concentration and strain values, mainly on apical dentin. CONCLUSIONS: Alveolar bone loss due to physiological aging and/or periodontal disease may lead to increased risk of restored tooth failure, although milled glass fiber and PEEK posts-and-cores provide more reparable fractures. CLINICAL SIGNIFICANCE: Custom-made glass fiber and PEEK post-and-cores are interesting options, since they enable clinicians to work with a single-body post-and-core system that avoid several materials interfaces and fits well in the root canal provided promising results to improve the failure behavior of restored roots, as they offer more reparable fractures even in situations of alveolar bone loss.

PEEK and fiberglass intra-radicular posts: influence of resin cement and mechanical cycling on push-out bond strength.

OBJECTIVES: To evaluate the bond strength of four types of posts (pre-fabricated fiberglass post, fiberglass post anatomized with composite resin, milled fiberglass post, and milled polyetheretherketone (PEEK) post), and two types of resin cements (conventional and self-adhesive) by assessing immediate bond strength and post-mechanical aging at each root third. MATERIALS AND METHODS: Bovine endodontically treated roots (16 groups, n = 8) were prepared and the posts were produced and luted; the specimens of aging groups were cycled (300,000 cycles under 50 N load at 1.2 Hz frequency); six slices of each root were obtained; push-out test was performed by using a universal testing machine (500 N load at 1 mm/min cross speed); fracture pattern was classified into five levels. The statistical analyses used were three-way ANOVA, Tukey's test (for bond strength), and Fisher's test (for fracture pattern) (α < 0.05). RESULTS: Differences were found between the cements for posts (conventional: p < 0.001; self-adhesive: p = 0.002), whereas no difference was found for root region (p = 0.941; p = 0.056, respectively); analysis of each root showed significant differences for cements (p < 0.001), posts (p < 0.001), and mechanical cycling (p = 0.001); in terms of double interaction, differences were found for posts and mechanical cycling (p = 0.005); no other interactions were observed (double or triple); the fracture pattern showed difference between the groups for both cements. CONCLUSIONS: Milled PEEK posts seem to be a good clinical option, but they require improvement of CAD-CAM technology and advances towards their adhesion. CLINICAL RELEVANCE: Milled posts are promising and can reduce clinical time for rehabilitation of extensively destroyed teeth.

Tratamento de lesão de mancha branca com infiltrante resinoso: relato de caso / Resin infiltration of enamel white spot lesion: a case report

O diagnóstico precoce de lesões de mancha branca no esmalte dental permite que um tratamento não invasivo seja indicado para a remineralização das lesões ativas. O objetivo deste trabalho foi relatar um caso clínico onde foi utilizado um infiltrante resinoso para o tratamento não invasivo de uma lesão de mancha branca do esmalte dental. Foi selecionado um paciente com 14 anos de idade, do sexo masculino, leucoderma, com boa saúde geral, de alto risco à cárie, que apresentava lesão de mancha branca no incisivo central superior direito. Devido ao aspecto rugoso e opaco da lesão, optou-se pela realização do tratamento do dente com uma resina infiltrante (Icon®, DMG, Hamburg, Alemanha). Inicialmente foram realizadas fotografias intraorais e radiografia do dente acometido para fins de documentação do caso e futuras comparações. Em seguida, o dente recebeu profilaxia e posterior tratamento pela técnica da resina infiltrante, de acordo com as instruções do fabricante. Para a verificação da efetividade do procedimento, o paciente foi avaliado imediatamente e após 2 meses da conclusão do tratamento. Concluiu-se que a técnica da resina infiltrante de baixa viscosidade para o tratamento da lesão de mancha branca do dente 11 foi satisfatória, pois foi capaz de promover a paralização da doença e o mascaramento da lesão de mancha branca naquele dente.

The early diagnosis of enamel white spot lesions allows adopting a non-invasive treatment to remineralize active lesions. The objective of this study was to report a case where an infiltrant composite was used to treat enamel white spot lesion. A Caucasian 14- year-old male patient, with overall good health, and high-risk for dental caries was selected. He presented white spot lesion in the upper right central incisor. Due to the rough and opaque appearance of the lesion, the treatment with an infiltrant resin (Icon®, DMG, Hamburg, Germany) was chosen. Initially, intraoral photos and x-ray of the affected tooth have been were taken for documentation purposes and future comparisons. Then, the tooth was cleaned and treated with the infiltrant resin following the manufacturer's instructions. To verify the effectiveness of the procedure, the patient was assessed immediately and 2 months after treatment. In conclusion, the technique of low-viscosity infiltrant resin was satisfactory because it was able to impair the progression of the disease and to camouflage the white spot lesion on that tooth.