| 1. |
- Kero, Timo, 1973, et al.
(författare)
-
Virtual variation simulation of CAD/CAM template-guided surgeries performed on human cadavers: Part II
- 2010
-
Ingår i: Journal of Prosthetic Dentistry. - 0022-3913 .- 1097-6841. ; 104:1, s. 48-55
-
Tidskriftsartikel (refereegranskat)abstract
- Material and methodsSeventeen computer-aided plans were used for virtual variation simulation of surgeries conducted on 17 human cadavers and 145 implants placed in the cadavers. For each surgery, 10,000 virtual surgeries were performed, resulting in 1,450,000 implant placements. The results from the virtual variation simulations were statistically compared with the results from the actual surgeries. The Mann-Whitney U test was used to compare the implant distributions (α=.05).ResultsIn the maxillae, the difference between the simulated average mean of the mean and the compared surgical average of the median was 0.22 mm (apex) and −0.35 mm (hex), and for the mandible, the corresponding values were −0.19 mm (apex) and −0.69 mm (hex). The simulated average mean of the range compared to the mean range of the maximum deviation results from the surgeries of the maxillae was 2.96 mm (apex) and 0.44 mm (hex), and 2.3 mm (apex) and 0.26 mm (hex) for the mandible. The implant distributions between the simulations and the surgeries were significantly different at both the hex (P
|
|
| 2. |
|
|
| 3. |
- Pettersson, Andreas, 1973, et al.
(författare)
-
Accuracy of CAD/CAM-guided surgical template implant surgery on human cadavers: Part I
- 2010
-
Ingår i: Journal of Prosthetic Dentistry. - 0022-3913 .- 1097-6841. ; 103:6, s. 334-342
-
Tidskriftsartikel (refereegranskat)abstract
- Statement of problem. An optimal method for approaching the clinical surgical situation, when using preoperatively, virtually planned implant positioning, is to transfer data to a CAD/CAM-guided surgical template with the definitive position of the implant placed after surgery. The accuracy of CAD/CAM-guided surgeries must be determined to provide safe treatment.Purpose. The purpose of this study was to compare the deviation between the position of virtually planned implants and the position of implants placed with a CAD/CAM-guided surgical template in the mandible and the maxilla in human cadavers.Material and methods. Ten maxillae and 7 mandibles, from completely edentulous cadavers, were scanned with CT, and 145 implants (Branemark RP Groovy) were planned with software and placed with the aid of a CAD/CAM-guided surgical template. The preoperative CT scan was matched with the postoperative CT scan using voxel-based registration. The positions of the virtually planned implants were compared with the actual positions of the implants. Data were analyzed with a t test (alpha=.05).Results. The mean measurement differences between the computer-planned implants and implants placed after surgery for all implants placed were 1.25 mm (95% Cl: 1.13-1.36) for the apex, 1.06 mm (95% Cl: 0.97-1.16) for the hex, 0.28 mm (95% Cl: 0.18-0.38) for the depth deviation, 2.64 degrees (95% Cl: 2.41-2.87) for the angular deviation, and 0.71 mm (95% Cl: 0.61-0.81 mm) for the translation deviation.Conclusions. The results demonstrated a statistically significant difference between mandibles and maxillae for the hex, apex, and depth measurements in the variation between the virtually planned implant positions and the positions of the implants placed after surgery with a CAD/CAM-guided surgical template.
|
|
| 4. |
- Pettersson, Andreas, 1973, et al.
(författare)
-
Accuracy of Virtually Planned and CAD/CAM-guided Implant Surgery on Plastic Models
- 2014
-
Ingår i: Journal of Prosthetic Dentistry. - : Elsevier BV. - 0022-3913 .- 1097-6841. ; 112:6, s. 1472-1478
-
Tidskriftsartikel (refereegranskat)abstract
- Statement of problemStudies of guided implant surgery have identified various methods that could influence accuracy. The present investigation was designed to limit the factors contributing to accuracy and to compare the results for 5 different surgeons.Purpose The purpose of this study was to evaluate any deviation between virtually planned and actually placed implants by 5 surgeons performing computer-aided design/computer-aided manufacturing (CAD/CAM)-guided implant surgery on duplicate plastic models.Material and methods Five surgeons participated in the study, and each received 5 plastic maxillary jaw models. Thus, 25 models were used for implant placement with CAD/CAM-fabricated surgical templates. Each model contained 6 implants; therefore, a total of 150 implants were placed. The virtually planned and actually placed implant positions were compared for the apex, hexagon, depth, and angle with 2 computed tomography scans that were matched with voxel-based registration software. In addition, any differences in the 4 parameters among the surgeons were statistically tested. The data were analyzed with the t test, ANOVA, and Scheffé test (α=.05).Results A statistically significant difference between the virtually planned and actually placed implant positions was observed for 3 of the 4 outcome variables (the apex, hexagon, and depth; P
|
|
| 5. |
- Kvam, K., et al.
(författare)
-
SOLUBILITY AND STRENGTH OF ZIRCONIA-BASED DENTAL MATERIALS AFTER ARTIFICIAL AGING
- 2013
-
Ingår i: Journal of Prosthetic Dentistry. - 0022-3913. ; 110:4, s. 281-287
-
Tidskriftsartikel (refereegranskat)abstract
- Statement of problem. Advanced high-strength dental ceramics based on zirconium oxide are widely used for dental restorations. However, their durability in liquids has been questioned. Purpose. The purpose of this study was to compare the flexure strength of zirconium dioxide materials designed for different sintering techniques before and after surface exposure to an acidic solution and to correlate the dissolution of the materials with strength data. Material and methods. An accelerated aging test, immersion in hot (80 degrees C) 4 vol% acetic acid was used to study the solubility of elements from the surface and the effect on the strength of 3 dental zirconia products: DY: Y-TZP material, milled in HIPed state (Denzir); DM: Mg-PSZ material, milled in dense-sintered state (Denzir M); and CY: Y-TZP material, milled from presintered block and then dense-sintered (Cercon base). Disks were prepared with a surface conditioning as for copings provided for dental restorations. After immersion for 1 week, the liquid was analyzed for a range of elements with ICP-MS. Biaxial flexure strength was measured for 3 samples (n=15) of each material: ground on a 20 mu m diamond disk without immersion; after 1 week's immersion in acetic acid; and after 1 week's immersion, grinding, and 1 more week in acid. Fracture probability was analyzed by maximum likelihood attribution of individual measurements to 1 or 2 Weibull distributions, each with 2 free parameters. Results. Dissolution was found to be limited. The total mass loss was less than 0.7 mu g/cm(2) forY-TZP and 3.5 mu g/cm(2) for Mg-PSZ. The mean strength was reduced for all materials after immersion in the fluid. Weibull statistics revealed 2 fracture mechanisms in Y-TZP milled in fully sintered condition. For DY only, 2 distributions significantly (P>.99) improved the description of individual treatment data. Conclusions. Y-TZP materials showed the highest biaxial flexure strength. Immersion for 1 week in hot 4 vol% acetic acid weakened all 3 zirconia materials by 100 to 200 MPa. Milling in the presintered state resulted in less variability than milling in the HIPed, state. Mg-PSZ exhibited the least variability.
|
|
| 6. |
|
|
