Photoelastic Analysis of Cemented or Screwed Implant-Supported Prostheses With Different Prosthetic Connections

Abstract

The aim of this study was to evaluate the stress distribution of different retention systems (screwed or cemented) associated with different prosthetic connections (external hexagon, internal hexagon, and Morse taper) in 3-unit implant-supported fixed partial dentures through photoelasticity. Six models were fabricated with photoelastic resin PL-2, and each model contained two implants of 4.0 × 10.0 mm. The models presented different retention systems (screwed and cemented) and different connections (external hexagon, internal hexagon, and Morse taper). The prostheses were standardized and fabricated in Ni-Cr alloy. A circular polariscope was used and axial and oblique (45°) loads of 100 N were applied in a universal testing machine. The results were photographed and analyzed qualitatively with a graphic software (Adobe Photoshop). The screwed retention system exhibited higher number of fringes for both axial and oblique loadings. The internal hexagon implant presented better and lower stress distribution for both cemented and screwed prostheses. The oblique loading increased the number of fringes in all models tested. The cemented retention system presented better stress distribution. The internal hexagon implant was more favorable according to the biomechanical standpoint. The oblique load increased stress in all systems and connections tested.

Immediate loading over lower prosthesis in edentulous mandibles: comparison between two types of prosthetic connection

“…The implants were distributed between the mental foramens, so that the two implants on the left side of each patient had Morse cone connections, while the two implants on the right side had external hexagon prosthetic connections, following a split mouth design (Figure 1). to loads [1][2][3] . In regard to the load conditions, it is necessary a period of 5-6 months for osseointegration of the implants in the maxilla and 3 months in the mandible.…”

“…In regard to the internal connections, it show higher flexural strength and better distribution of forces in relation to external systems, thus being biomechanically more favorable 1,8,12 . According to Streckbein et al 7 , internal connections present smaller microgaps between the implant and the abutment in relation to the external connections, which is highly desirable because the higher the space between implant and abutment, the greater the risk of biological and mechanical problems, such as failure by fatigue or perimplantitis.…”

“…The internal connections, especially the Morse cone, have shown better performance over the external connections in some experimental studies 1,3,10,[17][18] . Goiato et al 3 , showed better distribution of loads on implants with Morse cone connections when compared to external hexagon connections.…”

“…Assuming that the type of prosthetic connection interferes with the dispersion of loads around the implant, it also influences the perimplant bone loss. Therefore, several authors evaluate the perimplant bone loss in different types of prosthetic connections 1,3,[7][8][17][18] . In this study, the largest amount of bone loss was observed for the external hexagon group in comparison to the Morse cone group, but without statistically significant difference between them.…”

Regeneração tecidual guiada em implantodontia: Relato de caso clínico

“…Outro fator que deve ser considerado está relacionado com o tipo de conexão dos implantes utilizados, existe uma diversidade de geometrias disponíveis, entretanto a literatura tem sugerido que implantes com formato cone Morse apresentam melhor perfil biológico e mecânico principalmente para regiões de elevado quesito estético [9][10][11] . Portanto, o objetivo deste estudo foi realizar a descrição de um caso clínico, utilizando conceitos de regeneração tecidual guiada e, abordando toda fase de reabilitação.…”