Synovial chondromatosis and soft tissue chondroma: extraosseous cartilaginous tumor defined by FN1 gene rearrangement.

A fusion between fibronectin 1 (FN1) and activin receptor 2A (ACVR2A) has been reported previously in isolated cases of the synovial chondromatosis. To analyze further and validate the findings, we performed FISH and demonstrated recurrent FN1-ACVR2A rearrangements in synovial chondromatosis (57%), and chondrosarcoma secondary to synovial chondromatosis (75%), showing that FN1 and/or AVCR2A gene rearrangements do not distinguish between benign and malignant synovial chondromatosis. RNA sequencing revealed the presence of the FN1-ACVR2A fusion in several cases that were negative by FISH suggesting that the true prevalence of this fusion is potentially higher than 57%. In soft tissue chondromas, FN1 alterations were detected by FISH in 50% of cases but no ACVR2A alterations were identified. RNA sequencing identified a fusion involving FN1 and fibroblast growth factor receptor 2 (FGFR2) in the case of soft tissue chondroma and FISH confirmed recurrent involvement of both FGFR1 and FGFR2. These fusions were present in a subset of soft tissue chondromas characterized by grungy calcification, a feature reminiscent of phosphaturic mesenchymal tumor. However, unlike the latter, fibroblast growth factor 23 (FGF23) mRNA expression was not elevated in soft tissue chondromas harboring the FN1-FGFR1 fusion. The mutual exclusivity of ACVR2A rearrangements observed in synovial chondromatosis and FGFR1/2 in soft tissue chondromas suggests these represent separate entities. There have been no reports of malignant soft tissue chondromas, therefore differentiating these lesions will potentially alter clinical management by allowing soft tissue chondromas to be managed more conservatively.

Comparison of light-transmittance in dental tissues and dental composite restorations using incremental layering build-up with varying enamel resin layer thickness.

OBJECTIVES: To evaluate and compare light-transmittance in dental tissues and dental composite restorations using the incremental double-layer technique with varying layer thickness. MATERIALS AND METHODS: B1-colored natural teeth slabs were compared to dental restoration build-ups with A2D and B1E-colored nanofilled, supra-nanofilled, microfilled, and microhybrid composites. The enamel layer varied from 0.3, 0.5, or 1.2 mm thick, and the dentin layer was varied to provide a standardized 3.7 mm overall sample thickness (n = 10). All increments were light-cured to 16 J/cm2 with a multi-wave LED (Valo, Ultradent). Using a spectrophotometer, the samples were irradiated by an RGB laser beam. A voltmeter recorded the light output signal to calculate the light-transmittance through the specimens. The data were analyzed using 1-way analysis of variance followed by the post hoc Tukey's test (p = 0.05). RESULTS: Mean light-transmittance observed at thicker final layers of enamel were significantly lower than those observed at thinner final layers. Within 1.2 mm final enamel resin layer (FERL) thickness, all composites were similar to the dental tissues, with exception of the nanofilled composite. However, within 0.5 mm FERL thickness, only the supra-nanofilled composite showed no difference from the dental tissues. Within 0.3 mm FERL thickness, none of the composites were similar to the dental tissues. CONCLUSIONS: The supra-nanofilled composite had the most similar light-transmittance pattern when compared to the natural teeth. However, for other composites, thicker FERL have a greater chance to match the light-transmittance of natural dental tissues.

The effect of shade and curing mode on cure efficiency of dual-cure resin cements / Efeito da cor e do modo de cura na eficiência de cura de cimentos resinosos de cura dual

Objective: To evaluate the effect of shade and curing mode on cure efficiency of two dual-cure resin cements. Material and Methods: Two shades (A2 and TRANS) of two different dual-cure resin cements (G-CEM, GC Dental and SET PP, SDI) were submitted to different curing modes: light curing through a 2 mm thick ceramic disc (IPS Empress Esthetic, A2, Ivoclar Vivadent) for 20 s (16 J/cm2), 40 s (32 J/ cm2) or 80 s (64 J/cm2) performed immediately or with 1 or 5 min of delay. Fourier transform infrared spectroscopy (FT-IR) was used to evaluate the degree of conversion (DC) after 48 h. For the statistical analysis, data were submitted to threeway analysis of variance, followed by Tukey’s test for multiple comparisons (p<0.05). Results: Shade influenced DC (%) for the dual-cure resin cements tested (p=0.00001). TRANS shade showed lower DC (%) for both cements when there was no delay before light-curing (p=0.00001). Curing mode also influenced DC (%) for the dual-cure resin cements tested: radiant exposure greater than 32 J/cm2 and delaying light-curing for 1 to 5 min increased the DC (%) for both dual-cure resin cements evaluated. Conclusions: One minute delay prior to light-curing improved the cure efficiency and may be a more clinically acceptable approach to increase the degree of conversion of dual-cure resin cements.

Objetivo: Avaliar a influência da cor e do modo de polimerização no grau de conversão de dois cimentos resinosos duais. Material e Métodos: Duas cores (A2 e TRANS) de dois cimentos resinosos duais (G-CEM, GC Dental e SET PP, SDI) foram submetidos a diferentes modos de cura: fotoativação através de um disco de cerâmica de 2 mm de espessura (IPS Empress Esthetic, A2, Ivoclar Vivadent) por 20 s (16 J/cm2), 40 s (32 J/cm2) ou 80 s (64 J/cm2) realizada imediatamente ou após 1 ou 5 min de espera. Espectrometria com transformada de Fourier (FT-IR) foi utilizada para avaliação do grau de conversão (GC) após 48 h. Para a análise estatística, os dados foram submetidos à análise de variância com três fatores, seguida de teste de Tukey para comparações múltiplas (p=0.05). Resultados: A cor influenciou o GC (%) dos cimentos resinosos duais avaliados (p=0.00001). A cor TRANS resultou menor GC (%) para ambos os cimentos quando não houve espera antes da fotoativação (p=0.00001). O modo de cura também teve influência n o GC (%) dos cimentos resinosos duais avaliados: doses de energia superiores a 32 J/cm2 e espera de 1 ou 5 min antes da fotoativação aumentou o GC (%) dos dois cimentos resinosos duais avaliados. Conclusão: Um min de espera antes da fotoativação melhorou a eficiência de cura e pode ser uma abordagem clinicamente aceitável para aumentar o grau de conversão de cimentos resinosos duais.