Fracture resistance of teeth restored with cast post and core: An in vitro study

Abstract

Context:Influence of luting agent, design of tooth preparation for cast posts on tooth resistance to fracture.Aim:To evaluate fracture resistance of teeth restored with cast posts and cores with or without cervical ferrule and cemented with zinc phosphate, glass ionomer, or resin cement.Materials and Methods:Sixty single-rooted maxillary first premolars of similar sizes were selected. Biomechanical preparation and post space preparation for cast post was done for all samples and then they were divided into two groups (n=30). Cervical ferrule preparation was done for Group A, and Group B was prepared without any cervical ferrule. Both groups were further divided into three subgroups (1, 2, and 3; n=10) Cast posts for subgroups 1, 2, and 3 were cemented with zinc phosphate, glass ionomer, and resin cement, respectively. A shearing load was applied to indented buccal cusp of specimens at an angle of 45° in universal testing machine at a cross-head speed of 1 mm/min until fracture.Results:Specimens with ferrule (Group A) had significantly higher shear bond strength values (mean 1503.37 N) than specimens without ferrule (Group B) (mean 1052.09 N).Conclusion:Inclusion of ferrule in tooth preparations for posts increased the fracture resistance regardless of the luting agent.

Estudo Comparativo entre Pino de Fibra de Vidro e Pino Metálico Fundido: Uma Revisão de Literatura

“…Essa técnica se mostra eficiente e promissora também pela criação de um retentor individualizado, possuindo melhor adaptação, diminuição da linha de cimentação e embricamento mecânico e promoção de menor risco de fraturas radiculares irreversíveis, tendo em vista que o módulo de elasticidade é semelhante ao da dentina. (MANKAR et al, 2012).…”

“…Outro elemento a ser observado é a altura da férula, a qual vem sendo apontada como elemento que contribui com a maior resistência do dente, quando maior for sua altura. (AKKAYAN, 2004;MANKAR et al, 2012;KAR et al, 2017). Dentes com ausência de férula (0mm) apresentaram a menor resistência à fratura, já os dentes com férula de 3mm mostraram o melhor desempenho, tendo a maior resistência, apontando cada milímetro aumentado, acarreta no aumento da resistência e que o comprimento da férula impacta na resistência final da restauração.…”

“…Alguns materiais são utilizados como retentores intrarradiculares, entre eles os núcleos metálicos fundidos e os pinos pré-fabricados metálicos e não metálicos de fibra de vidro (MANKAR et al, 2012).…”

“…Os núcleos metálicos fundidos são feitos com ligas metálicas como níquel-cromo, prata-paládio e cobre-alumínio), sendo indicados devido à sua resistência e boa adaptação ao conduto radicular, apesar de serem esteticamente desvantajosos pela cor prata e mais tempo para confecção (MANKAR et al, 2012).…”

Effect of tapering internal coronal walls on fracture resistance of anterior teeth treated with cast post and core: In vitro study

“…Group II results in this study could be explained by a uniform stress distribution between post and the canal as the cement layer provides a buffer zone. 49 – 51 It has been shown in the crown cementation procedure that wall tapering affects zinc phosphate filtration phenomenon and escapement at cementation procedure 52 , 53 and alleviates hydrostatic pressure during cementation. 8 , 53 – 55 The taper degree was also shown to improve the cementation and seating of cast post and core similar to the cementation of crowns.…”