RESUMO
INTRODUCTION: Guided endodontics emerged as an alternative method capable of providing greater precision and accuracy to endodontic treatments. The aim of the present study was to compare the volume of dental tissue removed after guided endodontic access (GEA) and conventional endodontic access (CEA) to mandibular incisors and upper molars. METHODS: Twenty extracted human mandibular incisors and upper molars were selected and submitted to cone-beam computed tomographic (CBCT) examination. They were divided into 2 groups, G1 (mandibular incisors) and G2 (maxillary molars), and subdivided into G1a (CEA), G1b (GEA), G2a (CEA), and G2b (GEA). The Digital Imaging and Communications in Medicine files obtained by examining the CBCT scans were transferred to InVesalius software (Renato Archer Information Technology Center, Campinas, SP, Brazil) to calculate the initial volume of each tooth. G1b and G2b teeth were scanned with a device to plan and print the guides. After gaining endodontic access, new CBCT examinations were performed to calculate the final volume of each sample unit. The Student t test for independent samples compared the volumes among the groups. RESULTS: G1 group had an average volume reduction of 31.667 mm3 (10.62%) using CEA and 26.523 mm3 (10.65%) using GEA with no significant difference among the groups (P = .960). There was an average volume reduction of 62.526 mm3 (5.86%) in the G2 group using CEA and 45.677 mm3 (4.11%) using GEA with a significant difference among the groups (P = .004). CONCLUSIONS: GEA preserved a greater volume of dental tissue in extracted upper human molars than CEA; however, there was no significant difference between CEA and GEA in the volume of dental tissue removed from mandibular incisors.
Assuntos
Cavidade Pulpar , Endodontia , Brasil , Tomografia Computadorizada de Feixe Cônico , Humanos , Dente Molar/diagnóstico por imagem , Dente Molar/cirurgiaRESUMO
Objectives: The aim of this study was to evaluate the influence of the color of the resin luting cement in the final shade of minimally invasive porcelain veneers after accelerated artificial aging (AAA). Material and methods: 20 bovine teeth were collected, prepared and divided into two groups. The roots were removed and the buccal surfaces were polished to obtain a flat surface. Porcelain discs (IPS Empress Esthetic) were produced to a standardized shade (ET1) and thickness (0.6mm). The teeth and the veneers surfaces were prepared according to manufacturer recommendations. For group I (n=10), the White-Opaque (WO) base-paste was used and for group II (n=10) the Yellow (Y) base-paste. Each specimen was photocured for 60 s. The specimens were next subjected to AAA. They were submitted to color readings with a spectrophotometer in three moments: after the preparation (only the substrate), after the cementation and polymerization of the veneers and after the AAA. Were obtained values of L*, a* and b* and the total color change was calculated (?E*). Values obtained were subjected to statistical analysis in SPSS 17.0 for Windows with a significance of 0.05. Results: When comparing the cements, the Y cement showed higher ?E*, lower L* and higher b* after AAA than the WO. Conclusion: Both cements could mask the substrate color. With AAA, only the Y shade showed a ?E* clinically unacceptable, becoming more yellow (higher b*) and losing lightness (lower L*).
Objetivos: O objetivo do presente estudo foi avaliar a influência da cor do cimento resinoso na tonalidade final de facetas de porcelana minimamente invasivas, após envelhecimento artificial acelerado (EAA). Material e Métodos: 20 dentes bovinos foram coletados, preparados e divididos em dois grupos. As raízes foram removidas e a face vestibular foi polida para obter uma superfície plana. Discos de porcelana (IPS Empress Esthetic) foram confeccionados na cor ET1 e espessura de 0,6 mm. Os dentes e as superfícies dos discos foram preparados de acordo com as recomendações do fabricante. Para o grupo I (n=10) foi usado o cimento resinoso White-Opaque (WO) pasta-base, e para o grupo II (n-10) utilizou-se o Yellow (Y) pasta-base. Cada espécime foi fotopolimerizado por 60 s. Os espécimes foram então submetidos ao EAA. Eles foram submetidos a leituras de cor com auxílio de um espectro fotômetro em três momentos: após o preparo (apenas o substrato), após a cimentação e polimerização das facetas e após o EAA. Foram obtios valores de L*, a* e b* e o total da variação de cor foi calculado (?E*). Os valores obtidos foram submetidos à análise estatística no SPSS 17.0 para Windows, com nível de significância de 0,05. Resultados: O cimento Y apresentou maior ?E*, menor L* e maior b* após o EAA em comparação com o WO. Conclusão: Ambos os cimentos têm capacidade de mascarar a cor do substrato. Com o EAA, apenas o Y apresentou um valor de ?E* inaceitável clinicamente, se tornando mais amarelo (maior b*) e perdendo luminosidade (menor L*).