الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 111 |  |  |
| | | from | 111 | | |
Abstract
Summary and conclusion
Proper treatment planning and a sound understanding of restorative aspects of dental implants can prevent most implant failures.
This study was conducted to evaluate micro strains transmitted to the peri-implant bone supporting two types of hybrid abutment restorations made from three CAD/CAM materials in order to better choose the right type of implant supported restoration for different clinical situations.
Strain gauge (SG) analysis was conducted to evaluate the micro strain developed in the peri-implant bone supporting two types of customized crown-abutment combination; One piece hybrid-abutment-crowns (screw retained) and two piece hybrid-abutment with a separate crowns (cement retained) made from three different materials; cubic zirconia (CZ), polymer infiltrated ceramic network (Vita Enamic) and resin nano ceramic (Cerasmart).
A 3D printed model was fabricated using bone simulating material then implant fixture and two strain gauges were inserted in their planned position in the model. Eighteen crown-abutment combinations simulating a maxillary first premolar were fabricated using CAD/CAM system and divided into 2 groups (n=9) according to the design; hybrid abutment crown (Screw retained) and hybrid abutment with separate crown (cement retained), then each group was subdivided according to the type of material into 3 subgroups (n=3); Cubic zirconia (Ultra translucent multilayered zirconia), polymer infiltrated ceramic (Vita Enamic) and resin nano ceramic (Cerasmart).
A universal Testing machine was used for applying vertical loads (100 N) onto the central fossa in each subgroup sample for three times and the mean micro strain values of the three load applications were taken, the results were then statistically analyzed.
Results showed that the material and the design of the crown abutment combinations had a significant effect on micro strains developed in the supporting bone. Cubic Zirconia transmitted the highest micro strains followed by Cerasmart then Vita Enamic also one piece Cubic Zirconia transmitted higher micro strains than two piece design however there was no significant difference between the two designs in Cerasmart and Vita Enamic.
Conclusions:
Within the limitations of this in-vitro study, the following conclusions were drawn:
1. Different superstructure materials and designs affect the micro strains induced around dental implants.
2. Cubic zirconia hybrid-abutment-crowns (one-piece) developed the highest micro strains values within the supporting substrate while polymer infiltrated ceramic network crown-abutment combinations developed the least micro strains values.
3. Differences between micro strains developed with one piece hybrid-abutment-crowns (screw retained) and two piece hybrid abutments with separate crowns (cement retained) made from resin nano-ceramic or polymer infiltrated ceramic network material were comparable.
References