The stress distribution of a primary molar tooth restored with stainless steel crown using different luting cements.

BACKGROUND: The aim of this study is to evaluate the stress distributions of a primary molar tooth restored with a stainless steel crown (SSC) using resin and glass ionomer luting cements by Finite Element Analysis (FEA). METHODS: Original DICOM data of a primary molar was used to create a 3D model. One model was prepared as a tooth model with SSC. A 30 µm cement layer was used in model. Two different luting cements were tested in the study: self-cure adhesive resin cement, and glass ionomer cement. Vertical and oblique loads of 330 N were applied to simulate maximum bite force and lateral forces in the occlusal contact areas of the models. Maximum von Mises stress values in the models were evaluated as MPa. RESULTS: The maximum von Mises stress value was observed in the force application and general occlusal contact areas for all models. The maximum von Mises stress values were higher in the tooth model with SSC using self-cure adhesive resin cement (478.09 MPa and 214.62 MPa) than in the tooth model with SSC using glass ionomer cement (220.06 MPa and 198.72 MPa) in both vertical and oblique loading, respectively. CONCLUSIONS: Depending on the magnitude of the bite force on the SSC, fracture of the luting cement materials could occur if the stress exceeds the endurance limit of the luting cement. Cementation with glass ionomer cement may help to reduce stress levels in SSC restorations of primary molars in children.

Evaluation of the amount of residual monomer released from different flowable composite resins.

Today, resin materials are used in the restoration of permanent and deciduous teeth or as fissure sealants. The materials can contain different types of monomers (Bis-GMA, UDMA, TEGDMA). These monomers can be released into the oral cavity after polymerization. Residual monomers released from resin-containing restorative materials after polymerization have been reported to have negative effects on mechanical properties. The aim of our study is to evaluate the amount of residual monomers released after polymerization of different flowable composite resin materials using two different modes of LED light source. Composite disc samples (8 mm diameter/2 mm depth) prepared for each material group were polymerized using two different modes of the LED light device (Standard mode and extra power mode). HPLC (High Performance Liquid Chromatography) device was used to measure the amount of residual monomer release at 1 h, 1 day, 3 days and 7 days periods. Pairwise comparison of the differences between the materials was performed by Post-hoc test. For each residual monomer, the Kruskal Wallis test was used to analyze the difference between the materials in standard mode and the difference between the materials in extra power mode. According to the results of the study; Grandio flow flowable composite showed the highest release of TEGDMA and Bis-GMA while SDR® Flow flowable composite showed the lowest release of TEGDMA, Bis-GMA and UDMA. For all materials, the extra power mode resulted in more residual monomer release. TEGDMA and Bis-GMA release was detected in all tested flowable composites at all time periods.

Complex-Compound Odontoma: A Rare Clinical Presentation / Odontoma compuesto complejo: Una presentación clínica rara

ABSTRACT Odontomas can be detected as complex or compound variants and they rarely show the histologic characteristics of both types together. The tumor commonly associated with malocclusion, eruption disturbances and pathological anomalies, but they seldom cause bony expansion. Early detection and management of odontoma with multidisciplinary approach pose an important role to prevent disturbances associated with this common odontogenic tumor. Here we report a rare case of an odontoma which show the features of both complex and compound types and also cause bony expansion, eruption failure in an 8-year-old boy.

RESUMEN Los odontomas pueden detectarse como variantes complejas o compuestas y rara vez muestran la característica histológica de ambos tipos juntos. El tumor comúnmente se asocia con maloclusión, alteraciones de la erupción y anomalías patológicas, pero rara vez causan expansión ósea. La detección temprana y el manejo del odontoma con abordaje multidisciplinario representan un papel importante para prevenir las alteraciones asociadas con este tumor odontogénico común. Aquí presentamos un caso raro de un odontoma que muestra las características de los tipos complejos y compuestos y también causa expansión ósea, falla de erupción en un niño de 8 años.