| 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. |
- Sjögren, Göran, et al.
(författare)
-
Clinical evaluation of all-ceramic crowns (Dicor) in general practice.
- 1999
-
Ingår i: The Journal of prosthetic dentistry (Print). - 0022-3913 .- 1097-6841. ; 81:3, s. 277-284
-
Tidskriftsartikel (refereegranskat)abstract
- STATEMENT OF PROBLEM: There are few studies regarding all-ceramic full crowns placed by general practitioners; however, most dental restorations are carried out by general practitioners, and their clinical performance may be of particular interest. PURPOSE: Ninety-eight all-ceramic Dicor crowns placed in 46 patients regularly visiting a general practice were evaluated with the California Dental Association's (CDA) criteria. Mean and median ages of the crowns were 6.1 and 5.8 years, respectively (range 1.4 to 10. 9 years). Crowns were luted with either a glass ionomer, zinc phosphate, or resin composite cement. RESULTS. Of the 98 crowns, 82% were rated satisfactory. For marginal integrity, 51% were rated excellent. Fracture was registered in 14 all crowns, and 1 endodontically treated tooth with a Dicor crown was extracted because of root fracture; of the remaining 83 crowns, 55% were rated excellent for color. Corresponding figures for surface and anatomic form were 46% and 23%, respectively. The most common finding was slightly rough surfaces (64%). No statistically significant difference was observed for fracture rates obtained when the crowns luted with different luting agents were compared (P >.05). There was no more plaque or bleeding on probing (P >.05) in connection with the Dicor crowns than in the control surfaces.
|
|
| 3. |
|
|
| 4. |
- Braian, Michael, et al.
(författare)
-
Trueness and precision of 5 intraoral scanners for scanning edentulous and dentate complete-arch mandibular casts: A comparative in vitro study
- 2019
-
Ingår i: Journal of Prosthetic Dentistry. - : Elsevier BV. - 0022-3913 .- 1097-6841. ; 122:2, s. 129-136
-
Tidskriftsartikel (refereegranskat)abstract
- Statement of problem. Limited information is available on the trueness and precision of intraoral scanners (IOSs) for scanning dentate and edentulous casts. Purpose. The purpose of this in vitro study was to evaluate the trueness and precision of 5 different IOS devices for scanning a dentate and an edentulous cast in a standardized way for short arches and complete arches. Material and methods. Five IOS devices were used to scan 2 computer metric measured casts using a coordinate measuring machine (CMM). Both were scanned 15 times. All scans were carried out by 1 experienced operator in a standardized way. One cast was edentulous, and 1 was dentate. Five cylindrical landmarks were added to each cast. These cylinders made the measurement of point-to-point distances possible, dividing the tests into cross-arch measurements and intercylindrical (short-arch) measurements. The Student t test, Mann-Whitney test, and Levene test for equality were used to calculate the difference between the edentulous and dentate scans for both cross-arch and intercylindrical measurements (alpha=.05). Results. For the cross-arch measurements on the edentulous scans, the trueness values ranged between 6 mu m (Emerald P1-P2) and 193 mu m (Omnicam P1-P5) and for the intercylindrical measurements, between 2 mu m (Itero P4-P5) and -103 mu m (CS 3600 P1-P2). For the dentate cast, the cross-arch trueness values ranged between 6 mu m (CS 3600 P1-P2) and 150 mu m (TRIOS 3 P1-P5) and for the intercylindrical measurements, between 4 mu m (Itero P4-P5) and -56 mu m (Emerald P4-P5). Conclusions. Significant differences were found in scanning edentulous and dentate scans for short arches and complete arches. Trueness for complete-arch scans were <193 mu m for edentulous scans and <150 mu m for dentate scans. Trueness for short-arch scans were <103 mu m for edentulous scans and <56 mu m for dentate scans.
|
|
| 5. |
- Cui, Xinyue, et al.
(författare)
-
Esthetic appearances of anatomic contour zirconia crowns made by additive wet deposition and subtractive dry milling : A self-controlled clinical trial
- 2020
-
Ingår i: The Journal of prosthetic dentistry (Print). - : Elsevier BV. - 0022-3913 .- 1097-6841. ; 123:3, s. 442-448
-
Tidskriftsartikel (refereegranskat)abstract
- Statement of problem. Anatomic contour zirconia crowns are widely used in clinical dental practice because of their mechanical reliability and improved appearance. However, few studies have performed clinical evaluations of the esthetics of these crowns in terms of color and translucency gradient.Purpose. The purpose of this clinical trial was to compare the esthetic effect and color-matching behaviors of anatomic contour zirconia crowns manufactured with 3-dimensional (3D) gel deposition and dry milling methods.Material and methods. Twenty-seven premolar teeth of 27 participants received 2 identical anatomic contour zirconia crowns fabricated by additive 3D gel deposition or dry milling. Color differences (Delta E) between the crown and natural control teeth were measured by a dental shadematching device. Subjective color matching was rated by professionals using an extended visual rating scale for appearance match (EVRSAM) and by participants using a visual analog scale (VAS). Data were analyzed by using repeated measures ANOVA, the Bonferroni test, paired Student t test, Pearson chi-square test, and Wilcoxon test (alpha=.05).Results. Significant differences were found in SE between zirconia crown and core types (P<.05); however, there was no significant interaction between these factors (P>.05). The average SE of crowns made by wet deposition and dry milling were 2.45 +/- 1.60 and 4.55 +/- 1.54 (P<.05). The mean crown Delta E was significantly higher if a gold cast post-and-core was placed rather than a prefabricated fiber post and composite core (P<.05). Consistent with these findings, subjective color matching was significantly higher in the wet deposition group than in the dry milling group as rated by EVRSAM and VAS (P<.05).Conclusion. Anatomic contour zirconia crowns fabricated by additive wet deposition were better matched to adjacent teeth and had excellent esthetics in terms of color and translucency gradient.
|
|
| 6. |
- Gan, Dianne, et al.
(författare)
-
Effect of airborne-particle abrasion with a novel spherical abrasive on the zirconia surface
- 2023
-
Ingår i: The Journal of prosthetic dentistry (Print). - : Elsevier BV. - 0022-3913 .- 1097-6841. ; 130:6, s. 866-876
-
Tidskriftsartikel (refereegranskat)abstract
- Statement of problem. A novel zirconia-alumina composite (ZAC) particle has yet to be studied for airborne-particle abrasion in a bonding protocol for the zirconia surface.Purpose. The purpose of this in vitro study was to evaluate the shear bond force of resin cement to yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) when using spherical ZAC particles to conduct airborne-particle abrasion and modify the topography of Y-TZP.Material and methods. Spherical 30- to 70-μm ZAC particles were fabricated by using a hybrid gel technique. A total of 160 Ø6.6×4.0-mm zirconia disks were fabricated from 4 commercially available zirconia blanks, e.max ZirCAD zirconia (EM), NexxZr T zirconia (NE), Lava Plus High Translucency zirconia (LP), and Imagine High Translucency Zirconia (IM), by using computer-aided manufacturing technology. As-sintered specimens without further surface treatment were used as controls (ZR0). Surface treatment groups included sharp-edged alumina airborne-particle abrasion (ABC), 50 μm, 0.2 MPa; airborne-particle abrasion with ZAC particle at 0.2 MPa (2ZA); and airborne-particle abrasion with spherical ZAC particle at 0.4 MPa (4ZA). All surface treatment groups were airborne-particle abraded at the specified pressures for 10 seconds at a standardized distance of 10 mm. The surface roughness (Ra) and area roughness (Sa) of specimens from each group were measured. Following the application of an adhesive (Scotchbond Universal), Ø6.6×4.0-mm resin cement (RelyX Ultimate) buttons were fabricated for shear bond testing by using a universal testing machine at a 5-mm/min crosshead speed (n=10). The data were analyzed by using a 2-way ANOVA, Tukey HSD test, and regression analysis (α=0.05). Scanning electron microscopy (SEM) was performed to observe changes of the zirconia surface and the failure modes of each group before and after shear bond testing.Results. The mean ±standard deviation shear bond force values ranged from 272.6 ±41.4 N to 686.7 ±152.8 N. Statistically significant higher force values than those of the controls (P<.05) were obtained by using airborne-particle abrasion. No significant differences were found among any of the airborne-particle abrasion treatment groups (P>.05). The mean of Ra values ranged from 0.27 μm to 0.74 μm, and the mean of Sa values, from 0.48 μm to 1.48 μm. SEM observation revealed that the zirconia surface was made jagged by abrasion with sharp-edged alumina particles. The spherical ZAC particles create microcraters on the zirconia surface. Fractographic observation disclosed that failures were adhesive-cohesive failure modes with residual resin cement attached on the zirconia surface.Conclusions. The surface treatment of zirconia with sharp-edged alumina or the spherical ZAC abrasives improved the bonding force between the zirconia and resin cement. No statistically significant differences in shear bond force values were found between airborne-particle abrasion surface treatment groups.
|
|
| 7. |
- Gjelvold, Björn, et al.
(författare)
-
Accuracy of surgical guides from 2 different desktop 3D printers for computed tomography-guided surgery
- 2019
-
Ingår i: The Journal of prosthetic dentistry (Print). - : Elsevier. - 0022-3913 .- 1097-6841. ; 121:3, s. 498-503
-
Tidskriftsartikel (refereegranskat)abstract
- STATEMENT OF PROBLEM: Different factors influence the degree of deviation in dental implant position after computed tomography-guided surgery. The surgical guide-manufacturing process with desktop 3D printers is such a factor, but its accuracy has not been fully evaluated.PURPOSE: The purpose of this in vitro study was to evaluate the deviation in final dental implant position after the use of surgical guides fabricated from 2 different desktop 3D printers using a digital workflow.MATERIAL AND METHODS: Twenty 3D-printed resin models were prepared with missing maxillary premolar. After preoperative planning, 10 surgical guides were produced with a stereolithography printer and 10 with a digital light-processing (DLP) printer. A guided surgery was performed; 20 dental implants (3.8×12 mm) were installed, and a digital scan of the dental implants was made. Deviations between the planned and final position of the dental implants were evaluated for both the groups.RESULTS: A statistically significant difference between stereolithography and DLP were found for deviation at entry point (P=.023) and the vertical implant position (P=.009). Overall lower deviations were found for the guides from the DLP printer, with the exception of deviation in horizontal implant position.CONCLUSIONS: The tested desktop 3D printers were able to produce surgical guides with similar deviations with regard to the final dental implant position, but the DLP printer proved more accurate concerning deviations at entry point and vertical implant position.
|
|
| 8. |
- Hammoudi, Wedad, et al.
(författare)
-
Long-term results of a randomized clinical trial of 2 types of ceramic crowns in participants with extensive tooth wear
- 2022
-
Ingår i: The Journal of prosthetic dentistry (Print). - : Elsevier. - 0022-3913 .- 1097-6841. ; 127:2, s. 248-257
-
Tidskriftsartikel (refereegranskat)abstract
- STATEMENT OF PROBLEM: Evidence is sparse regarding the long-term outcomes of restorative treatment of patients with extensive tooth wear.PURPOSE: The purpose of this long-term prospective randomized clinical trial was to evaluate the performance and success rate of pressed lithium disilicate (LD) and translucent zirconia (TZ) crowns in participants with extensive tooth wear.MATERIAL AND METHODS: A total of 62 participants with extensive tooth wear (17 women, 45 men; mean age 44.8 years; range 25-63 years) received a total of 713 crowns, LD=362 and TZ=351. Both types of crowns had chamfer preparations and were adhesively luted with dual-polymerizing composite resin cement (PANAVIA F 2.0; Kuraray Noritake Dental Inc). The restorations were clinically reevaluated on average 14, 31, 39, 54, and 65 months after insertion of the crowns according to the modified United States Public Health Service (USPHS) criteria.RESULTS: After an observation period of up to 6 years, the survival rate for both types of crowns was 99.7%, with 1 lost LD crown after 1 year as a result of loss of retention and 1 lost TZ crown after 3 years because of tooth fracture at the cemento-enamel junction. The success rates were similar for both types of crowns: 98.6% for LD and 99.1% for TZ. Reasons for failures were that 3 participants in each group developed apical lesions, minimal ceramic fractures, or their crowns were rebonded after loss of adhesion. Assessment of color at baseline was significantly different with a better match for LD (84.8% Alfa, 15.2% Bravo) than for TZ crowns (36.5% Alfa, 63.5% Bravo), including TZ crowns with veneered porcelain (P<.001). Secondary caries and cracks did not occur. A post hoc analysis of clinical performance did not indicate any significant differences between extensive tooth wear with primarily mechanical or chemical factors.CONCLUSIONS: No differences were found between the 2 types of ceramic materials concerning the long-term success and clinical performance, except that TZ crowns were rated by a blinded clinician as less esthetic than LD crowns. The use of high-strength ceramic materials, as well as reliable adhesive bonding, are probably the key factors in the long-term success of ceramic crowns in participants with extensive tooth wear independent of the specific etiology.
|
|
| 9. |
- Hansson, Mia, et al.
(författare)
-
Shear bond strength of adhesive cement to zirconia : effect of added proportion of yttria for stabilization
- 2024
-
Ingår i: The Journal of prosthetic dentistry (Print). - : Elsevier. - 0022-3913 .- 1097-6841.
-
Tidskriftsartikel (refereegranskat)abstract
- Statement of problem: Zirconium dioxide (zirconia) cannot be etched in a clinical setting, but zirconia restorations with minimal to no micromechanical bonding are approved and widely used in contemporary dentistry. However, information on the shear bond strength of zirconia and adhesive cement, on the effect of an added proportion of yttria, and on the effect of aging is lacking.Purpose: The purpose of this in vitro study was to evaluate the shear bond strength of cement luted to zirconia and the effect of aging.Material and methods: A total of 131 test specimens were made from 4 zirconia materials with different amounts of yttria added to formulate yttria-partially stabilized zirconia (Y-PSZ); 3Y-PSZ (n=32), 4Y-PSZ (n=34), and 2 5Y-PSZs (n=32 and n=33). A dual-polymerizing cement and 10-methacryloyloxydecyl dihydrogen phosphate-containing primer were used. All specimens were stored in water at 37 °C, half of them for 24 hours and the other half for 6 months. After aging, the specimens were subjected to a shear bond strength test with a notched crosshead according to the International Organization for Standardization (ISO) 29022:2013 standard. The data were analyzed using the independent 2-sample t test, ANOVA, and the Levene test (α=.05).Results: The 3Y-PSZ material had higher mean ±standard deviation shear bond strength (31.83 ±12.80 MPa) compared with 4Y-PSZ (23.34 ±7.66 MPa) after 24 hours of aging in water and higher (28.98 ±14.03 MPa) than 4Y-PSZ (14.35 ±9.62 MPa) and one of the 5Y-PSZ (16.05 ±11.34 MPa) after 6 months. Debonding before loading occurred in all groups except for one of the 5Y-PSZ groups.Conclusions: Zirconia without macromechanical retention, regardless of an added proportion of yttria, showed high shear bond strength, but the tested materials also had a high coefficient of variance, which, in practice, leads to the risk of the occasional debonding of zirconia restorations.
|
|
| 10. |
|
|
