Effect of metal conditioners on the adhesive bonding of resin cements to cast titanium

Objective: To assess the effect of metal conditioners on the bond strength between resin cements and cast titanium. Method and Materials: Commercially pure titanium (99.56%) was cast using an arc casting machine. Surfaces were finished with 400-grit silicon carbide paper followed by air abrasion with 50-mu m aluminum oxide. A piece of double-coated tape with a 4-mm circular hole was then positioned on the metal surface to control the area of the bond. The prepared surfaces were then divided into 4 groups (n=10): G1, unprimed Panavia F; G2, Alloy Primer-Panavia F; G3, unprimed Bistite DC; G4, Metaltite-Bistite DC. Forty minutes after insertion of the resin cements, the specimens were detached from the mold and stored in water at 37 C for 24 hours. Shear bond strength was performed in a testing machine (MTS 810) at a crosshead speed of 0.5 mm/min. Data were analyzed using ANOVA and Tukey's test with a .05 significance level. The fractured surfaces were observed through an optical microscope at 10x magnification. Results: the G1 group demonstrated significantly higher shear bond strength (17.95 MPa) than the other groups. G3 (13.79 MPa) and G4 (12.98 MPa) showed similar mean values to each other and were statistically superior to G2 (9.31 MPa). Debonded surfaces generally presented adhesive failure between metal surfaces and resin cements. Conclusion: While the Metaltite conditioner did not influence the bond strength of the Bistite DC cement, the Alloy Primer conditioner significantly decreased the mean bond strength of the Panavia F cement.

Customized fiber glass posts. Fatigue and fracture resistance

Purpose: To evaluate the root fracture strength of human single-rooted premolars restored with customized fiberglass post-core systems after fatigue simulation. Methods: 40 human premolars had their crowns cut and the root length was standardized to 13 mm. The teeth were endodontically treated and embedded in acrylic resin. The specimens were distributed into four groups (n=10) according to the restorative material used: prefabricated fiber post (PFP), PFP+accessory fiber posts (PFPa), PFP+unidirectional fiberglass (PFPf), and unidirectional fiberglass customized post (CP). All posts were luted using resin cement and the cores were built up with a resin composite. The samples were stored for 24 hours at 37 degrees C and 100% relative humidity and then submitted to mechanical cycling. The specimens were then compressive-loaded in a universal testing machine at a crosshead speed of 0.5 mm/minute until fracture. The failure patterns were analyzed and classified. Data was submitted to one-way ANOVA and Tukey's test (alpha= 0.05). Results: The mean values of maximum load (N) were: PFP - 811.4 +/- 124.3; PFPa - 729.2 +/- 157.2; PFPf - 747.5 +/- 204.7; CP - 762.4 +/- 110. Statistical differences were not observed among the groups. All groups showed favorable restorable failures. Fiberglass customized post did not show improved fracture resistance or differences in failure patterns when compared to prefabricated glass fiber posts. (Am J Dent 2012;25:35-38).

Resistance to compression of weakened roots subjected to different root reconstruction protocols

Objective: This study evaluated, in vitro, the fracture resistance of human non-vital teeth restored with different reconstruction protocols. Material and methods: Forty human anterior roots of similar shape and dimensions were assigned to four groups (n=10), according to the root reconstruction protocol: Group I (control): non-weakened roots with glass fiber post; Group II: roots with composite resin by incremental technique and glass fiber post; Group III: roots with accessory glass fiber posts and glass fiber post; and Group IV: roots with anatomic glass fiber post technique. Following post cementation and core reconstruction, the roots were embedded in chemically activated acrylic resin and submitted to fracture resistance testing, with a compressive load at an angle of 45 degrees in relation to the long axis of the root at a speed of 0.5 mm/min until fracture. All data were statistically analyzed with bilateral Dunnett's test (alpha=0.05). Results: Group I presented higher mean values of fracture resistance when compared with the three experimental groups, which, in turn, presented similar resistance to fracture among each other. None of the techniques of root reconstruction with intraradicular posts improved root strength, and the incremental technique was suggested as being the most recommendable, since the type of fracture that occurred allowed the remaining dental structure to be repaired. Conclusion: The results of this in vitro study suggest that the healthy remaining radicular dentin is more important to increase fracture resistance than the root reconstruction protocol.

Resistência adesiva de sistemas autocondicionante e convencional frente a diferentes substratos e associação ao laser Nd:YAG: estudo in vitro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo comparativo da influência do condicionamento do esmalte humano e bovino com laser de Er:YAG sobre a resistência de união de um sistema adesivo convencional e de um sistema adesivo autocondicionante

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da smear layer e da condição de tratamento da dentina (in vivo e in vitro), sobre a resistência de união

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito de diferentes soluções irrigadoras na resistência de união dentina radicular - adesivo autocondicionante

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Resistência de união e limite de fadiga de nichos confeccionados em resina composta e cimentos à base de ionômero de vidro

Pós-graduação em Reabilitação Oral - FOAR

Efeito de tratamentos térmicos na resistência à tração e na dureza Vickers do Ti c.p. e da liga Ti-6Al-4V obtidos por fundição odontológica

Pós-graduação em Reabilitação Oral - FOAR

Influência do volume do preparo oclusal para inlays e do material restaurador na distribuição de tensão e resistência à fratura de pré-molares

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Restaurações inlays em cerâmicas feldspáticas injetadas em pré-molares: efeito da estratégia de cimentação e da ciclagem mecânica na resistência adesiva entre dentina e restauração

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da influência da ciclagem mecânica sobre a resistência de união ao cisalhamento entre uma cerâmica de recobrimento estético e duas cerâmicas infiltradas por vidro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo longitudinal da resistência adesiva aos substratos dentários de sistemas adesivos associados ou não ao Nd:YAG Laser

Pós-graduação em Odontologia Restauradora - ICT

Desenvolvimento de um Gnatodinamômetro digital para estudo e análise da força dos músculos da mastigação

Pós-graduação em Engenharia Mecânica - FEG

Avaliação da resistência ao cisalhamento e da durabilidade de união entre sistemas para reparo em metalocerâmicas e titânio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)