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- Milleding, P, et al.
(author)
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Surface energy of non-corroded and corroded dental ceramic materials before and after contact with salivary proteins
- 1999
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In: European Journal of Oral Sciences. - 0909-8836 .- 1600-0722. ; 107, s. 384-392
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Journal article (peer-reviewed)abstract
- After sintering and autoglazing, the surface free energy of seven different dental ceramic materials was determined by contact angle measurements, using a Dynamic Adsorption Tester and three different standard probe liquids, before and after in vitro corrosion and also before and after incubation with human whole saliva. The surface free energy was calculated from the Young-Dupre-equation and the polar and non-polar components were determined. The total surface free energy (range 50±5 mN/m) did not differ significantly between the different ceramic materials or between corroded and non-corroded specimens. The basic surface chemical character persisted after corrosion, although reduced to a lower level, which probably reflects ion exchange processes at the exposed surfaces. After saliva incubation the basic component of the surface free energy increased, which may be interpreted as the result of salivary proteins binding to the basic surface with their acidic groups, orienting their basic sites towards the bulk phase. Selective adsorption of proteins to biosurfaces will no doubt influence both microbiological colonisation and cell adhesion, although the exact mechanisms are not known.
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| 2. |
- Milleding, P, et al.
(author)
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Two years of clinical experience with Procera titanium crowns
- 1998
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In: International Journal of Prosthodontics. - 0893-2174 .- 1139-9791. ; 11:3, s. 224-32
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Journal article (peer-reviewed)abstract
- PURPOSE: The purpose of the study were to evaluate the clinical performance of the Procera porcelain-fused-to-titanium crown system in general practice during a 2-year period, and to evaluate the performance of a new low-fusing porcelain as a veneering material on titanium.MATERIALS AND METHODS: A number of consecutive complete-coverage crowns (40) in 25 patients (14 women and 11 men) with a mean age of 53.1 years (range 35 to 79 years) were made according to the Procera (Nobel Biocare) technique in a 3-month period. The titanium copings were fabricated from solid rods of pure titanium using spark erosion and copy-milling technique, whereafter they were veneered with a new type of low-fusing ceramic material. The crowns were evaluated using the CDA criteria at baseline and after 2 years.RESULTS: The general failure rate was low and was restricted to one carious lesion, one porcelain fracture, and one loss of a crown resulting from failure of retention of a post and core. The most frequent single reason that the "excellent" color level was not recorded was a "too-high value." A slightly dull or granular porcelain surface was observed both at baseline and after 2 years. Overall, the responses of the patients were positive.CONCLUSION: Within the limitations of the study it can be concluded that porcelain-veneered Procera titanium crowns can be used as an alternative to other porcelain-fused-to-metal systems. However, conclusions should be made with caution from the results of this study because of the limited number of patients and crowns and the short observation period.
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