Determination of the fabricating conditions for the preferable marginal and internal adaptation of the mica crystal castable ceramic crown.
This study was performed to find an acceptable internal adaptation of castable ceramics containing mica and beta-spodumene crystals. The influences of factors, expansion rate of phosphate-bonded investment (A), anisotropic expansion (B), diecoating (C), shrinkage during crystallization (D), and interaction (A x B), and (A x C) were tested by twice repeated experiments under block design according to L8(2)(7) orthogonal array. Estimated mean ranges under the conditions combined with significant factors were judged by considering the criteria of the ideal internal gap (about 50 microm). The ideal marginal fit of less than 50 microm and uniform cement space about 50 microm around the axial wall could be achieved by a combination of optimum levels of A1B1C2D2. However, the estimated mean gap at the cusp tip and central fossa of occlusal inside by this combination were about 120 microm. The near intolerable gaps could not be reduced.
Ukon
Shinichi
S
Department of Oral Rehabilitation, Division of Fixed Prosthodontics, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ward, Fukuoka 814-01 Japan. baronuk@college.fdcnet.ac.jp
Ishikawa
Masatugu
M
Tohyama
Monica
M
Sato
Hironobu
H
D000538:Aluminum Silicates; D000704:Analysis of Variance; D003442:Crowns; D003734:Dental Casting Investment; D003735:Dental Casting Technique / Q000295:instrumentation; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design / Q000379:methods; D006801:Humans; D016014:Linear Models; D008903:Minerals; D003765:Models, Dental
D000538:Aluminum Silicates; D003734:Dental Casting Investment; D008903:Minerals; D003776:Dental Porcelain; C026378:spodumene; C011934:mica