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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

EFFECT OF CYCLIC LOADING ON THE VERTICAL MICROGAP OF LONG-SPAN ZIRCONIA FRAMEWORKS SUPPORTED BY 4 OR 6 IMPLANTS

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Author(s):
Tiossi, Rodrigo [1] ; Gomes, Erica Alves [2] ; Lapria Faria, Adriana Claudia [2] ; Silveira Rodrigues, Renata Cristina [2] ; Ribeiro, Ricardo Faria [2]
Total Authors: 5
Affiliation:
[1] Univ Fed Fluminense, Sch Dent, Dept Prosthodont, BR-24020140 Niteroi, RJ - Brazil
[2] Univ Sao Paulo, Ribeirao Preto Sch Dent, Dept Dent Mat & Prosthodont, BR-14049 Ribeirao Preto, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: JOURNAL OF PROSTHETIC DENTISTRY; v. 112, n. 4, p. 828-833, OCT 2014.
Web of Science Citations: 8
Abstract

Statement of problem. Few studies have investigated the microgap of long-span complete-arch fixed dental prosthesis zirconia frameworks. Purpose. The purpose of this study was to evaluate the effects of cyclic loading on the vertical microgap of maxillary 12-unit prostheses supported by 4 implants and on 14-unit prostheses supported by 6 implants. Material and methods. One-piece zirconia frameworks were fabricated with a computer-aided design/computer-aided manufacturing technique and divided into 2 groups (n=5): a group of 12-unit prostheses and a group of 14-unit prostheses. The vertical microgap between the frameworks and prosthetic abutments was measured with an optical microscope (80x) under 2 reading conditions. Condition 1 (1-screw test): 1A, the screw on implant 1 was tightened and readings were made on all implants; 1B, the screw was changed to implant 4 (implant 6 for the 14-unit group) and readings were made on all implants. Condition 2: the microgap was measured with all screws tightened before cyclic loading (2A). Specimens were submitted to 200 N underwater (37 C) cyclic loading at a 2-Hz frequency for 1 x 106 cycles. Microgap reading condition 2 was repeated after cyclic loading (2B). The data were submitted to a linear mixed-effects model for statistical comparison (alpha=.05). Results. A lower (P<.05) vertical microgap (mu m) was found for the 12-unit group (reading conditions: 1A, 47.93; 1B, 43.83; 2A, 11.77; and 2B, 11.25) compared to the 14-unit group (1A, 94.87; 1B, 112.56; 2A, 21.28; and 23, 16.90). No differences were found when each group was compared before and after cyclic loading (P>.05). Conclusions. The vertical microgap was significantly reduced after tightening all the screws in the framework, possibly leading to a nonpassive situation. Longer-span frameworks showed an increased microgap. Cyclic loading had no influence on the vertical microgap within each group. (AU)

FAPESP's process: 11/01506-0 - A digital image correlation analysis and non-linear 3D-FEM on the strain distribution of screwed and cemented fixed partial dentures fabricated by a CAD/CAM system in titanium and zirconia
Grantee:Ricardo Faria Ribeiro
Support type: Regular Research Grants
FAPESP's process: 10/00124-3 - Influence of mechanical cycling on loosening of retention screw in cemented and screwed fixed partial dentures fabricated with titanium and zirconia cad/cam system. In vitro analysis and non-linear analysis by 3D-FEA.
Grantee:Erica Alves Gomes
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 10/02218-5 - Influence of mechanical cycling on loosening of retention screw in cemented and screwed fixed partial dentures fabricated with titanium and zirconia cad/cam system. In vitro analysis and non-linear analysis by 3D-FEA
Grantee:Ricardo Faria Ribeiro
Support type: Regular Research Grants
FAPESP's process: 10/19221-9 - A digital image correlation analysis and non-linear 3D-FEM on the strain distribution of screwed and cemented fixed partial dentures fabricated by a CAD/CAM system in titanium and zirconia
Grantee:Rodrigo Tiossi
Support type: Scholarships in Brazil - Post-Doctorate