Volume 1 Issue 3

Research Article: Effect of Aligned Implants on The Stress in Partial Fixed Prosthesis Submitted To Axial or Oblique Loads Exerted on The Molar: A Photoelastic Study

Bianca Piccolotto Tonella, Marcelo Ferraz Mesquita, Valentim Adelino Ricardo Barao, Mauro Antonio de Arruda Nobilo, Carmem Silvia Pfeifer and Rafael Leonardo Xediek Consani*

Objective: The aim of this study was to verify the effect of aligned implants on the stress in partial fixed prosthesis submitted to axial or oblique loads.
Methods: A photoelastic model was made for each implant type (EH - external hexagon, IH - internal hexagon, and MT - Morse taper) in which were placed three aligned implants and a Ni-Cr framework with three units. The prostheses were subjected to axial (AL) or oblique (OL) loads of 100 N applied at first molar. A polariscope analyzed the photoelastic behavior of the models with Fringes software in Matlab platform.
Results: Qualitative analysis: EH/AL - Greater stress on the implant apexes of the second premolar and first molar, and lower intensity on second molar; IH/AL - Similar stress at the implant apexes of the first and second molars, and larger intensity at the second premolar; MT/AL - Higher stress with different concentrations at regions of the implants; EH/OL - Lower stress intensity at the apexes of the second molar and second premolar when compared to first molar; IH/OL - Stress with similar intensity at implant apexes; and MT/OL - Greater stress at the second molar, and smaller at the first molar and second premolar. Quantitative analyses: EH/AL (T=15.32 and Nf=1.53, IH/AL (T=13.29 and Nf=1.32), MT/AL (T=15.29 and Nf=1.52), EH/OL (T=15.29 and Nf=1.52, IH/OL (T=14.15 and Nf=1.41), and MT/OL (T=17.08 and Nf=1.70). Conclusions: Aligned implants in partial fixed prosthesis promoted different stresses when the first molar was submitted to axial or oblique loads.

Cite this Article: Tonella BP, Mesquita MF, Ricardo Barao VA, de Arruda Nobilo MA, Xediek Consani RL, et al. Effect of Aligned Implants on The Stress in Partial Fixed Prosthesis Submitted To Axial or Oblique Loads Exerted on The Molar: A Photoelastic Study. Sci J Res Dentistry. 2017;1(3): 057-062.

Published: 07 November 2017

Research Article: Influence of Tooth Thickness on Depth of Cure and Degree of Conversion of a Photo-Activated Resin Composite Irradiated Through the Tooth

Yujiao Li , Shuang Gao, Samson Alexander Tarimo, Hongyan Zhao, Hong Zhang, Li Liu, Xuan Ren, Wenyue Li and Zhimin Zhang*

Objective: To investigate the influence of trans-dental photo-curing on the Depth of Cure (DoC) and Degree of Conversion (DC) of a resin composite irradiated by a light curing unit operating in different curing modes.
Methods: Six main groups were formed in accordance with different tooth thicknesses which were further divided into six subgroups (n=5) according to light modes. DoC was evaluated by means of an ISO4049 standard scraping technique. Fourier Transformation Infrared (FTIR) spectroscopy was used to determine DC.
Results: DoC and DC decreases with increasing intervening tooth thickness. At 3mm tooth thickness, except for Turbo mode, there is no obvious curing performance. Turbo and High light modes could achieve the resin composite 2mm DoC even when tooth structure was 1.0mm thick. However for the rest of the light modes, the 2mm composite layer could adequately be cured when the tooth thickness was 0.5mm only. FTIR analysis mean DC values for the through-tooth-structure indirect curing were lower than the 45%-75% direct curing values. Among the groups, 0.5mm group had the highest DoC and DC mean values, 2.5 mm and 3mm groups had the lowest mean values. The composite resin showed lower DoC and DC mean values when irradiated indirectly compared to control direct curing (p < 0.005). 0.5 mm and Turbo light groups recorded the highest DoC and DC values than other groups, differences between tooth thickness groups were statistically significant with p < 0.005. Conclusions: (1) A nano-composite resin cured through different tooth thickness will have lower DoC and DC compared to direct curing. (2) In clinical operation, composite should be directly cured, indirect curing must be avoided at all possibilities.

Cite this Article: Li Y, Gao S, Tarimo SA, Zhao H, Zhang Z, et al. Influence of Tooth Thickness on Depth of Cure and Degree of Conversion of a Photo-Activated Resin Composite Irradiated Through the Tooth. Sci J Res Dentistry. 2017;1(3): 050-056.

Published: 27 October 2017

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