The effect of a ceramic coating on the cpTi-porcelain bond strength.
OBJECTIVE
To investigate the bond strength between cpTi and low fusing porcelains after different treatments.


METHODS
72 patterns were covered with a ceramic coating and invested with phosphate-bonded material (group A), another 72 were invested with magnesia material (group B) and all cast with cpTi. 31 solid castings were selected from each group. The castings of group B were ground and sandblasted, while the castings of group A were only sandblasted. Aluminum content of the metal surface was determined by EDS and castings were submitted to a 3-point bending test to determine the modulus of elasticity (E). The porcelains Duceratin Plus, Noritake Ti22 and Triceram were applied respectively and specimens were submitted to a 3-point bending test. The fracture mode and the remaining porcelain were determined by optical microscopy and SEM/EDS. Bond strength and fracture mode were calculated by two-way ANOVA.


RESULTS
The E of groups A and B was 98.3 GPa and 98.6 GPa respectively. The bond strength was 26+/-3 MPa (Duceratin Plus), 28+/-3 MPa (Noritake Ti22), 27+/-2 MPa (Triceram) for group A and 24+/-1 MPa, 29+/-2 MPa, 27+/-1 MPa for group B respectively. No significant differences were found for the same porcelain between the two groups (p<0.05). A significant difference was found between Duceratin Plus and Noritake Ti22, for group B (p<0.05). The mode of failure was mainly adhesive for all specimens. A significant reduction in aluminum was recorded in all subgroups.


CONCLUSIONS
The special coating of patterns makes the Ti casting procedure inexpensive, without reducing the metal-ceramic bond strength.
Papadopoulos
Triantafillos D
TD
Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Thivon 2, Athens 115 27, Greece. trpapad@dent.uoa.gr
Spyropoulos
Konstantin D
KD
D000268:Adhesiveness; D000537:Aluminum Oxide / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D001840:Dental Bonding; D003734:Dental Casting Investment / Q000737:chemistry; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D055119:Elastic Modulus; D004577:Electron Probe Microanalysis; D006801:Humans; D008277:Magnesium Oxide / Q000737:chemistry; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D018583:Pliability; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
D020099:Coated Materials, Biocompatible; D003734:Dental Casting Investment; D003764:Dental Materials; C098572:Duceratin Porcelain; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain; D008277:Magnesium Oxide; D015019:Yttrium; D015040:Zirconium; D014025:Titanium; D000537:Aluminum Oxide; C028541:zirconium oxide; C091417:yttria