ISSN:1496-4155    

DOI:10.1111/j.1708-8240.1992.tb00673.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

In the total etch technique for chemically adhesive composite restorations, the phosphoric acid penetrates only 10 pm or less into the vital dentin with the dentinal tubules being filled with the odontoblast processes. The acid is completely removed by subsequent air‐water jet spray washing. The tubule apertures are perfectly sealed by the protective bonding agent layer with the resin tags adhering to the tubule walls and the resin‐impregnated dentin surface. Isolation of the cavity from moisture contamination is required for only less than a few seconds after drying the etched cavity until the bonding agent coating and after this coating until the composite resin placement. Such a short time for isolation is quite easy even without a rubber dam when a trained assistant is cooperat

ISSN:1496-4155    

DOI:10.1111/j.1708-8240.1992.tb00674.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Porcelain occasionally fractures from ceramometal fixed partial dentures following final cementation. Repair of these porcelain fractures can be a challenging task. When the problem occurs on anterior teeth, it is especially difficult because the repair must not only be durable, but esthetically pleasing as well. Although composite resins can be used for some repairs, it is often difficult to match the color and texture to the surrounding intact porcelain. In addition, the bonding between the resin and porcelain is susceptible to margin leakage, which may ultimately cause an esthetic failure. Techniques involving a cemented porcelain‐fused‐to‐metal overcasting have often been successful in restoring the fixed partial denture to form and function. Although the esthetic result of a porcelain/metal overcasting can be quite successful, retention of the overcasting is sometimes poor. The compromised retention and resistance form is due to lack of interproximal walls on the underlying fractured unit. To improve the retention of the overcasting, the following technique of tin plating the overcasting and fractured unit prior to cementing with a composite resin cement is pres

ISSN:1496-4155    

DOI:10.1111/j.1708-8240.1992.tb00675.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

This study investigated the microleakage between glass‐ionomer cement and Silux or Herculite with and without Scotchbond 2. Cavities were prepared in polymerized composite resin samples and “restored” with a glass ionomer cement with and without Scotchbond 2. The samples were thermocycled and immersed in 0.05% crystal violet solution for 2 hours, then embedded in clear casting resin, sectioned, and examined with an optical microscope. The results indicated that a high degree of dye penetration was found in samples of GC and Silux, and GC and Herculite without Scotchbond 2. The use of Scotchbond 2 significantly reduced the degree of dye penetration, but did not completely eliminate dye penetr

ISSN:1496-4155    

DOI:10.1111/j.1708-8240.1992.tb00676.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Two adhesives, Super Bond and Panavia, were evaluated for shear bond strength to dentin. Twenty human teeth were used for each adhesive. Bonding sites were prepared in dentin (600 grit) and the adhesives applied according to the manufacturers’instructions. Bond strengths were determined with an Instron testing machine at 24 hours. Super Bond developed the strongest bond of 21.59 ± 3.91 MPa. Panavia produced a lower bond strength of 2.68 ± 1.45 MPa. Statistically, Super Bond was found to have a stronger bond than Panavia. The same two adhesives were applied to Ni‐Cr‐Be specimens and compared to Comspan. Twenty Rexillium III specimens were used for each adhesive at 24 hours and 20 for thermocycling. The metal specimens were ground flat (600 grit) and then air abraded with 50‐micron aluminous oxide. The adhesives were applied to the metal surface in accordance with the manufacturers’instructions. One group was tested at 24 hours while the second group was tested after thermocycling (2,500 cycles at 6°C to 60°C). At 24 hours, Super Bond had a significantly stronger bond than the other materials. Comparison of the 24‐hour to thermocycled bond strengths found Comspan had a significant increase in bond strength, Panavia had no significant change and Super Bond had a significant decrease in bond strength. After 2,500 thermocycles, Comspan, Panavia, and Super Bond were not significantly different i

ISSN:1496-4155    

DOI:10.1111/j.1708-8240.1992.tb00677.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The purpose of this study was to determine by visual inspection and by scanning electron microscopy (SEM) whether commercially available, topical, acidulated phosphate fluoride (APF) and neutral sodium fluoride (NaF) agents cause surface roughening of five sealant materials: two unfilled resins, two filled resins, and one glass‐ionomer material. In addition, the effect of treatment with 1.23% APF and sonification on weight of an unfilled and a filled sealant was compared to treatment with controls. Unfilled sealants exhibited no surface changes visually or on micrographs following any treatment. Filled sealants and the glass‐ionomer sealant exhibited visually apparent changes depending on the treatment. SEM inspection of filled sealants with visually apparent changes showed loss of filler particles whereas the glass‐ionomer sealant exhibited apparent destruction both of the matrix and the filler particle. No significant differences in weight were found between sonicated and unsonicated specimens. However, significant loss of weight was found with filled sealant specimens, but not unfilled sealant specimens, treated with 1.23% APF gel as compared with the specimens treated with water. The results of thisin vitrostudy indicate that preventive therapies that combine use of topical fluorides and sealants may cause deterioration of filled sealants and glass‐ionomer sealant material, but not unfilled s

ISSN:1496-4155    

DOI:10.1111/j.1708-8240.1992.tb00678.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The purpose of this study was to determine the facial profile preferences in a sample of 1,189 Asian teenagers (aged 15.3 ± 3.2 years). Five facial profile types were computer‐generated by trained personnel (orthodontists and oral maxillofacial surgeons) to represent distinct facial types. Subjects were asked to rank the profiles in descending order of attractiveness. The ranking was as follows: orthognathic profile, bimaxillary retrusive profile, bimaxillary protrusive profile, mandibular retrognathic profile, and mandibular prognathic profile. The differences in rank scores between all the profile types were statistically significant (p<0.05). Assessment of profile types among lay personnel could provide clinicians an indication into the relative attractiveness among profile types and health care workers in treatment prioritization among dysmorphic facial typ

ISSN:1496-4155    

DOI:10.1111/j.1708-8240.1992.tb00679.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Adhesion of porcelain to dentin may be important in those cases with little remaining enamel. The purpose of this study was to determine the bond strength of porcelain to dentin using a dentin adhesive (All‐Bond) and compare it to the enamel bond strength. Sixty human molar teeth had either a dentin or enamel bonding site prepared by flat grinding to a 600 grit. The teeth were divided into three groups of 20 each. Sixty porcelain cylinders were prepared, hydrofluoric acid etched on one end and silane treated. Twenty of the cylinders were bonded to enamel, 20 bonded to dentin with a dentin adhesive to be tested at 48 hours, and 20 bonded to dentin with a dentin adhesive to be tested after 24 hours of thermocycling (800 cycles at 6°C to 60°C). The specimens were tested in an Instron at a crosshead speed of 0.5 mm/minute. The following bond strengths were found: enamel (19.0 ± 2.9 MPa), dentin at 48 hours (14.4 ± 5.4 MPa), and dentin after thermocycling (10.1 ± 3.8 MPa). When this data was subjected to statistical analysis (ANOVA), there was a significant difference between the groups. A Scheffe's test found that the dentin‐porcelain bond at 48 hours was stronger than the thermocycled group, and that the enamel bond was significantly stronger than the two dent

ISSN:1496-4155    

DOI:10.1111/j.1708-8240.1992.tb00680.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The etched‐metal, resin‐bonded fixed partial denture has evolved rapidly from its origination as an extracoronal splint. Technologic advancements in both resin chemistry and retentive surface etching techniques have markedly improved the quality of the prosthesis. Today, resin‐bonded fixed partial dentures are an effective, conservative means of replacing missing teeth when specific contraindications–long spans, insufficient sound enamel, malocclusion, pathologic occlusal habits–are identified and avoided. A universally‐accepted standard preparation does not exist for resin‐bonded fixed partial dentures; rather, common principles of tooth reduction are agreed upon by most authors. This case report details necessary modifications in typical preparation and framework design that must be included to maintain a midline diastema when such spacing is required or preferred b

ISSN:1496-4155    

DOI:10.1111/j.1708-8240.1992.tb00681.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

ISSN:1496-4155    

DOI:10.1111/j.1708-8240.1992.tb00682.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY