PROPRIEDADES MECÂNICAS DE MATERIAIS RESINOSOS UTILIZADOS PARA RESTAURAÇÕES DE LESÕES CERVICAIS / MECHANICAL PROPERTIES OF RESIN MATERIALS USED IN CERVICAL LESIONS RESTORATIONS

Introdução: Desordens oclusais complexas podem ocasionar a fratura de tecido dentário e o aparecimento de hipersensibilidade dentinária, levando o profissional a difícil escolha do material restaurador. Objetivo: Comparar as propriedades mecânicas (resistência flexural e módulo de elasticidade) de cinco materiais utilizados para restauração de lesões cervicais com a dentina bovina. Métodos: Foram utilizadas duas resinas compostas comerciais de baixa viscosidade: Opallis Flow (OL) e Natural Flow (NF); duas resinas composta comerciais de viscosidade média: Z-100 (Z100) e Opallis (OP); e um cimento de ionômero de vidro modificado por resina Riva Light Cure (RL). Para a confecção dos corpos-de-prova, o material foi inserido uma matriz de silicone e fotoativado (n=12). Para a confecção dos corpos-de-prova de dentina, raízes de dentes bovinos foram utilizadas. As raízes foram seccionadas em uma máquina de corte (Isomet 1000) e lixados para obtenção dos palitos de dentina (10x1x1mm). Após, os corpos-de-prova foram levados a uma máquina de ensaio universal (Instron 3342) sob uma velocidade de 0,5 mm/min para o ensaio de resistência flexural e módulo de elasticidade. Os dados foram submetidos ANOVA um fator e Tukey (α=0.05). Resultados: Houve diferença significativa entre os grupos experimentais testados (p<0,05). A dentina bovina apresentou valores superiores de resistência flexural (169,30 ± 19,60 MPa) e os menores valores de módulo de elasticidade (4,48 ± 0,32 GPa). Conclusão: Nenhum material utilizado na pesquisa apresenta características mecânicas próximas daquelas encontradas na dentina bovina.Palavras-chave: Módulo de Elasticidade. Materiais Dentários. Dentina.AbstractIntroduction: Complex occlusal disorders can lead to tissue tooth fracture and may cause dentin hypersensitivity, thus dental professional have difficult to choose the ideal restorative material Objective: To compare flexural strength and modulus of elasticity, of five materials used for restoration of cervical lesions with bovine dentin. Methods: Two low viscosity resins: Opallis Flow (OL) and Natural Flow (NF), two medium viscosity resins: Z-100 (Z100) and Opallis (OP), and ionomer resin modified glass Riva Light Cure (RL) were tested materials. The specimens were made by silicon matrix and halogen light curing unit (Optilux 501) (n = 12). For dentin specimens, twelve bovine teeth without coronal portion were used. The roots were cut using a cutting machine (Isomet 1000) to obtain dentin sticks (10x1x1mm). Flexural strength test was conducted on a universal testing machine (Instron 3342) at a crosshead speed of 0.5 mm/min. Data were submmited to ANOVA (one variation factor) and Tukey (α=0.05). Results: There were significant differences between experimental groups tested (p < 0.05). Bovine dentin showed higher flexural strength values, which were statistically significant (169.30 ± 19.60 MPa). Bovine dentin showed lower modulus values (4.48 ± 0.32 GPa). Conclusion: No material used in this study showed similar mechanical properties from those found in bovine dentin.Keywords: Elastic Modulus. Dental Materials. Dentin

Clinical evaluation of postoperative sensitivity using self-etching adhesives containing glutaraldehyde

The present clinical study aimed to assess the postoperative sensitivity (POS) after 48 hours and seven days in occlusal restorations bonded with three different adhesive systems, two of them containing glutaraldehyde. The restorative procedures were performed using the three-step etch-and-rinse Adper SBMP-Plus adhesive (SBMP), the two-step etch-and-rinse Gluma Comfort One Bond + Desensitizer adhesive (GC+D) and the all-in-one self-etching/priming I Bond (IB) adhesive, which also has glutaraldehyde in its formula. All cavities were restored with Filtek Supreme nanoparticle composite resin. After 48 hours and seven days the patients were recalled and the postoperative sensitivity evaluated. The data analyzed by non-parametric Friedman test showed no significant differences in POS among the three tested groups after 48 hours and seven days

Adhesive systems: important aspects related to their composition and clinical use

This literature review article addresses the types and the main components of different etch-and-rinse and self-etch adhesive systems available in the market, and relates them to their function, possible chemical interactions and infuence of handling characteristics. Scanning electron microscopy (SEM) images are presented to characterize the interface between adhesives and dentin. Adhesive systems have been recently classifed according to their adhesion approaches in etch-and-rinse, self-etch and glass ionomer. The etch-and-rinse systems require a specifc acid-etch procedure and may be performed in two or three steps. Self-etch systems employ acidic monomers that demineralize and impregnate dental substrates almost at the same time. These systems are separated in one or two steps. Some advantages and defciencies were noted for etch-and-rinse and self-etch approaches, mainly for the simplifed ones due to some chemical associations and interactions. The SEM micrographs illustrate different relationships between adhesive systems and dental structures, particularly dentin. The knowledge of composition, characteristics and mechanisms of adhesion of each adhesive system is of fundamental importance to permit the adoption of ideal bonding strategies under clinical conditions

Influence of whitening gel on pulp chamber temperature rise by in-office bleaching technique

INTRODUCTION: Dental bleaching is a conservative method for the aesthetic restoration of stained teeth. However, whitening treatments are likely to cause adverse effects when not well planned and executed. OBJECTIVE: This study evaluated the influence of whitening gel on temperature rise in the pulp chamber, using the in-office photoactivated dental bleaching technique. MATERIAL AND METHOD: The root portion of an upper central human incisor was sectioned 3mm below the cemento-enamel junction. The root canal was enlarged to permit the insertion of the K-type thermocouple sensor (MT-401) into the pulp chamber, which was filled with thermal paste to facilitate the transfer of heat during bleaching. Three photosensitive whitening agents (35% hydrogen peroxide) were used: Whiteness HP (FGM), Whiteness HP Maxx (FGM) and Lase Peroxide Sensy (DMC). An LED photocuring light (Flash Lite - Discus Dental) was used to activate the whitening gels. Six bleaching cycles were performed on each group tested. The results were submitted to one-way ANOVA and LSD t-test (&#945;<0.05). RESULT: The lowest mean temperature variation (ºC) was detected for Lase Peroxide Sensy (0.20), while the highest was recorded for Whiteness HP (1.50). CONCLUSION: The Whiteness HP and Whiteness HP Maxx whitening gels significantly affected the temperature rise in the pulp chamber during bleaching, and this variation was dependent on the type of whitening gel used

Influence of whitening gel on pulp chamber temperature rise by in-office bleaching technique

INTRODUCTION: Dental bleaching is a conservative method for the aesthetic restoration of stained teeth. However, whitening treatments are likely to cause adverse effects when not well planned and executed. OBJECTIVE: This study evaluated the influence of whitening gel on temperature rise in the pulp chamber, using the in-office photoactivated dental bleaching technique. MATERIAL AND METHOD: The root portion of an upper central human incisor was sectioned 3mm below the cemento-enamel junction. The root canal was enlarged to permit the insertion of the K-type thermocouple sensor (MT-401) into the pulp chamber, which was filled with thermal paste to facilitate the transfer of heat during bleaching. Three photosensitive whitening agents (35% hydrogen peroxide) were used: Whiteness HP (FGM), Whiteness HP Maxx (FGM) and Lase Peroxide Sensy (DMC). An LED photocuring light (Flash Lite - Discus Dental) was used to activate the whitening gels. Six bleaching cycles were performed on each group tested. The results were submitted to one-way ANOVA and LSD t-test (α<0.05). RESULT: The lowest mean temperature variation (ºC) was detected for Lase Peroxide Sensy (0.20), while the highest was recorded for Whiteness HP (1.50). CONCLUSION: The Whiteness HP and Whiteness HP Maxx whitening gels significantly affected the temperature rise in the pulp chamber during bleaching, and this variation was dependent on the type of whitening gel used