PubMed · 3268928
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R Herrmann. 1988. [Ceramic inlay (III)].. https://pubmed.ncbi.nlm.nih.gov/3268928/
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STATEMENT OF PROBLEM: Chemical bonding plays a major role in the adherence between metal and porcelain. The formation of an oxide layer on solder material has not been described in the literature. It is unknown whether the application of solder negatively affects the bond strength between porcelain and metal. PURPOSE: This in vitro study assessed the effect of solder on the bond strength between metal and porcelain. MATERIAL AND METHODS: Forty 20 x 6 x 0.5 mm patterns were divided into test (20) and control (20) groups. Test samples were perforated and repaired with solder, and 2 layers of opaque and dentin porcelain subsequently were applied on all samples. The samples were subjected to a 3-point flexural test on a screw-driven mechanical testing machine at a crosshead speed of 0.5 mm/min. Failure type (adhesive vs cohesive) was quantified by digitizing photographs of test and control samples. Three samples in each group also were examined with an SEM coupled with an x-ray energy-dispersive spectroscopy apparatus (SEM/EDS). Means and standard deviations of loads at failure, sample thickness, and surface area covered with porcelain were calculated, and data were analyzed with Student t test (P < or = 0.05). RESULTS: The mean fracture load for test samples was significantly greater than for control samples (P = 0.0038). Test samples also were significantly thicker (mean thickness difference 0.14 mm) (P = 0.0001). When the data were controlled for thickness by using a multiple linear regression analysis, no significant difference was found (P = 0.68). Test samples had a greater surface area covered with opaque porcelain (P = 0.0006) as determined by visual inspection. CONCLUSION: In this study, soldered and nonsoldered samples did not show any significant difference in porcelain-to-metal bond strength. Visual analysis revealed a significant difference in the amount of porcelain remaining on the fracture surface of the test and control samples; a complete quantitative elemental analysis with SEM/EDS is in progress.
BACKGROUND: Prosthodontics is the dental specialty responsible for diagnosis, rehabilitation and maintenance of patients with complex clinical conditions involving missing or deficient teeth and/or craniofacial tissues. The essence of the specialty is expert treatment planning. OVERVIEW/LITERATURE REVIEWED: In recent years, new approaches and technology have been introduced as a result of research performed in universities and by industry. The field of prosthodontics continues to evolve owing to a better understanding of the biology of the oral cavity and the introduction of new techniques and improved biomaterials. Improvements in periodontal and oral surgical techniques, implant procedures and materials, esthetic restorative materials, and jaw tracking recorders and articulators have led to enhanced functional and esthetic oral and maxillofacial prostheses. CONCLUSIONS AND CLINICAL IMPLICATIONS: The complexities of today's technical and clinical procedures and the higher expectations for more esthetically pleasing dentistry by the general patient population have placed a premium on teamwork involving general dentists, specialists and dental technicians.
Failures that occur in titanium-ceramic restorations are of concern to clinicians. The formation of poorly adhering oxide on titanium at dental porcelain sintering temperatures causes adherence problems between titanium and porcelain, which is the main limiting factor in the fabrication of titanium-ceramic restorations. To overcome this problem a 1-microm thick Si3N4 coating was applied to a titanium surface using a plasma-immersion implantation and deposition method. Such a coating serves as an oxygen diffusion barrier on titanium during the porcelain firings. The protective coating was characterized in the as-deposited condition and after thermal cycling. Cross sections of Ti/Si3N4-porcelain interface regions were examined by various electron microscopy methods and by energy dispersive analysis of X-rays to study the Si3N4 film's effectiveness in preventing titanium oxidation and in forming a bond with porcelain. The experiments have shown that this Si3N4 coating enables significant improvement in Ti-ceramic bonding.