Analysis of CAD-CAM technology in the manufacture of implant-supported single prostheses and its effect on adaptation under mastication simulation and in the presence of microorganisms.

Author(s)

Jéssica Marcela de Luna Gomes

• Document type: Doctoral Thesis
• Press: Araçatuba. 2022-05-02.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araçatuba
• Defense date: 2022-03-08
• Advisor: Eduardo Piza Pellizzer; Cristiane Duque; Sandra Lúcia Dantas de Moraes

Abstract

This thesis was divided into two chapters, with similar objectives, however, different groups were evaluated in each chapter. The general objective of this work was to evaluate which technique will present a better mechanical and biological behavior when screwed implant-supported prostheses to external hexagon were submitted to five years of masticatory simulation. In both chapters, the specimens were subjected to analysis of misfit (vertical and horizontal), torque and quantification of microorganisms before and after mechanical cycling (30° angle, at 37°C, 5 x 10⁶ cycles with 150N of load at a frequency of 2.0Hz). The quantification of microorganisms was performed after immersion of the specimens in a multi-species biofilm composed of four microorganisms, including three strains of bacteria (Fusobacterium nucleatum Streptococcus mutans and Streptococcus oralis) and a strain of yeast (Candida albicans) incubated for 115h. For chapter 1, 30 specimens were made, divided into three groups (n=10 per group) being UCoCr (Ucla with Cr-Co strap); Ucal (Castable Ucla); Fc (Wax milled + metal alloy casting) and as a result we can observe that before cycling, regarding the vertical marginal misfit there was a significant difference when comparing the UCoCr group to the FC and Ucal groups (p<0.05). The Ucal group showed the highest mean difference after cycling. As for the horizontal misfit before cycling, there was a significant difference when comparing the UCoCr group to the FC (p<0.05). The FC group showed the highest positive mean difference (overcontour) after cycling when compared to all other groups, and it was significant when compared with UCoCr (undercontour) (p<0.05). As for torque, the UCal group showed the highest mean difference after cycling. As for the quantification of viable cells, it was not possible to observe a difference between the groups (p>0.05) before cycling. After cycling, the Ucal group had the lowest amount of microorganisms (p<0.05). The Fc group was the one that presented the higher adhesion of post-cycling microorganisms. It can be concluded that the technique that presents the best mechanical behavior in terms of adaptation to marginal misfit (vertical and horizontal) and torque is the conventional technique, based on UCLA with Cr-Co (UCoCr) strap. However, the hybrid technique (Fc) was the one that presented the highest amount of viable cells after the simulation of 5 years of prosthesis use. For chapter 2, 50 specimens were made, divided into five groups (n=10 per group), being UCOCR (Ucla with Cr-Co strap); CADIN (custom abutment (intraoral scanner)); CADEX (custom abutment (extraoral scanner); TIBASEIN (Tibase (intraoral)); TIBASEEX (Tibase (extroral)) and as results we saw that before cycling a greater vertical marginal misfit for the UCoCr group. There was a significant difference when comparing the group UCoCr to CadEX and CadIN groups (p<0.05) Regarding horizontal marginal misfit for UCoCr, TibaseIN and TibaseEX groups presenting subcontour, there was a significant difference when comparing the UCoCr group to CadEX and CadIN groups p<0.05 ( As for the total amount of viable cells, it was possible to observe a difference between the UCoCr groups and the CadIN groups (p<0.05).After cycling, there was no significant difference in the comparison of the analyzed groups (p> 0.05. Considering the CAD CAM system (CadIN+CadEX) vs. Tibase (TibaseIN+TibaseEX) a significant difference was not identified. However, in the comparison intraoral system (CadIN+TibaseIN) vs. Extraoral (CadEX+TibaseEX) identified a difference significant difference (p≤0.001), more favorable to the extraoral system. As for the horizontal marginal misfit with subcontour for the UCoCr group, followed by TibaseIN and TibaseEX. There was a significant difference when the UCoCr group was compared to the CadEX and CadIN groups (p<0.05). The CadIN and CadEX groups presented values of positive horizontal marginal misfit (overcontour) and significant difference when compared to the groups: UCoCr, TibaseIN and TibaseEX (p<0.05). As for the total amount of viable cells, it was possible to observe a significant difference for the UCoCr group (p<0.05) with a greater number of cells compared to the other groups. Thus, it can be concluded that TiBaseIn or TiBaseEx can be considered the techniques that would clinically present the highest longevity, as they associate low values of marginal misfit (horizontal and vertical), in addition to low adhesion of microorganisms. (AU)

• FAPESP's process: 18/13179-2 - Analysis of CAD-CAM technology in the manufacture of single-unit implant-supported prostheses and the effect of the simulation of chewing on the adaptation and in the presence of microorganisms
• Grantee: Jéssica Marcela de Luna Gomes
• Support Opportunities: Scholarships in Brazil - Doctorate