摘要:

SummaryAetiological factors which lead to occlusal collapse have been surveyed and the clinical symptomatology of this syndrome emphasized. The sequence of periodontal treatment as well as suggestions for re‐establishing and recording new jaw relations are discussed in detai

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1975.tb00907.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SummaryThe historical development and important properties of composite resins are briefly reviewed. Experimental work has been undertaken to examine the marginal adaptation of three commercially available composite resins in 100 Class II and Class V restorations; dye penetration tests were used and the measurement of the gap at the tooth/ restoration interface as recorded in photographs obtained by scanning electron microscopy of replicas. In Class V restorations showing marginal leakage by dye penetration the gap at the tooth/restoration interface was in all cases greater cervically than occlusally. The results underline the uncertainty of obtaining a good marginal seal with composite resins both peripherally and along internal line angles.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1975.tb00908.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1975.tb00909.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SummaryThe electrochemical behaviour of the component phases of dental amalgam, viz. Ag3Sn (γ), Ag2Hg3(γ1), Sn7–8Hg (γ2), Cu3Sn, Cu6Sn5and a composite of γ1 +γ2 phases were evaluated in saline solution by standard anodic polarization techniques. Using multi‐electrode theory a theoretical polarization diagram was constructed from the composite phases and compared with an anodic polarization profile attained from conventional dental amalgam. A strong agreement was obtained.From analysis of the electrochemical reactions it was found that the passivity of γ2 is due to the formation of stannous and/or stannic oxide (hydroxide) and that the corrosion failure of dental amalgam occurs through the dissolution of this passive oxide in γ2 at potentials of −250 mV Vs. SCE with the formation of tin oxychloride. The corrosion behaviour of Cu6Sn5is similar to that of γ2 phase and its presence impairs the corrosion resistance of dental amalgam. If the copper containing phase is Cu3Sn, it will be passive in Ringer's solution, possibly as a result of Tamman's ‘multiple

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1975.tb00910.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SummaryOral ability to recognize forms and oral motor ability were examined in twenty children, aged 11 years, with normal occlusion. In the RF‐test (recognition of form) the children identified the test pieces quicker but with a higher frequency of misidentification of the test pieces than a group of 17‐year‐old boys studied earlier. The effect of learning on the children was substantial with much quicker and greater certainty from one examination to another. Identification time and misidentification were positively correlated (individuals with long identification time also had a high frequency of errors).In the MA‐test (oral motor ability) the children required a longer time to assemble the halves of the test pieces than did 17‐year‐old boys. A considerable effect of learning was found also in the MA‐test. The results of the RF‐test and the MA‐test varied independently of each other for which reason the two tests measure different component

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1975.tb00911.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SummaryThe chemical treatment of enamel surfaces is an approach in obtaining increased bonding of dental materials to tooth surfaces. Three etching solutions commonly used at present are 50% H3PO4, 50% H3PO4attenuated with 7% zinc oxide and 50% citric acid.The effects of these three conditioning solutions on normal and polished enamel surfaces and on the interfaces between untreated enamel and etched enamel surfaces were studied by scanning electron microscopy.The variable etching pattern observed with each of the acids made a comparative study difficult. This was further complicated by the dependence of the etching action on prism orientation on polished enamel surfaces. Additional factors that have to be considered are the presence of prismless enamel and perikymata.Surface profile recordings of polished and acid‐etched polished enamel surfaces provided some quantitative measure of the etching action of the conditioning solutions.The 50% citric acid solution had the mildest etching action while 50% H3PO4and 50% H3PO4attenuated with 7% zinc oxide elicited comparable response

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1975.tb00912.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SummaryAssessments of the practical deficiencies of polymethylmethacrylate in service have been carried out by several workers. Some of these studies and one further one have been compared so as to seek any common factors, especially those concerned with the age of the appliance at failure. Times of vulnerability for different types of dentures have been demonstrated, and the scope for time‐based studies in the laboratory and in service has been discusse

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1975.tb00913.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY