FEM evaluation of cemented-retained versus screw-retained dental implant single-tooth crown prosthesis

Abstract

Prosthetic rehabilitation of partial or total edentulous patients is today a challenge for clinicians and dental practitioners. The application of dental implants in order to recover areas of missing teeth is going to be a predictable technique, however some important points about the implant angulation, the stress distribution over the bone tissue and prosthetic components should be well investigated for having final long term clinical results. Two different system of the prosthesis fixation are commonly used. The screw retained crown and the cemented retained one. All of the two restoration techniques give to the clinicians several advantages and some disadvantages. Aim of this work is to evaluate all the mechanical features of each system, through engineering systems of investigations like FEM and Von Mises analyses. The FEM is today a useful tool for the prediction of stress effect upon material and biomaterial under load or strengths. Specifically three different area has been evaluated through this study: the dental crown with the bone interface; the passant screw connection area; the occlusal surface of the two different type of crown. The elastic features of the materials used in the study have been taken from recent literature data. Results revealed an adequate response for both type of prostheses, although cemented retained one showed better results over the occlusal area.

Keywords: FEM analysis; bone tissue; dental implant; load.

Figure 1

3D CAD model after the reverse engineering process.

Figure 2

Model of the implant screw and other component. A: Virtual Model; B: Original Model; C: Abutment; D: Passant connection screw.

Figure 3

Virtual Model analysed in the system representing bone dental implant and prosthetic crown. A: Cemented retained prosthesis; B: Screw retained prosthesis.

Figure 4

Axial load over the 3D model.

Figure 5

Dental implant screw-crown system. A: Cemented retained prosthesis; B: Screw retained prosthesis with the hole in the occlusal area.

Figure 6

Zone 1 margin between crown and bone tissue. A: Cemented retained prosthesis; B: Screw retained prosthesis. MPa Mega Pascal.

Figure 7

Zone 2 margin between bone and dental implant screws. A: Cemented retained prosthesis; B: Screw retained prosthesis. MPa Mega Pascal.

Figure 8

Zone 3 margin on the occlusal area. A: Cemented retained prosthesis; B: Screw retained prosthesis. The hole in the screw retained is clearly a wicked point of the structure.