摘要:

SummaryRepeatability of the centric jaw relation recorded with the one‐handed push‐back technique was tested on six subjects. Condylar positions were radiographically recorded using cold cure acrylic indices to lock the jaws in centric. This was done on two occasions with an interval of 1 week between recordings. Utilizing the subtraction technique, the radiographs of these condylar positions were compared. Intra‐individual differences were not found to be significant and it may be concluded that centric relation registered with the push‐back technique results in accurate and consistant repositioning of the condyles in the glenoi

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1985.tb00614.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryA method is described for quantitativein vivowear measurements on Class I and II composite restorations. Class I gold inlays were made in an acrylic premolar and molar. Over the occlusal parts of the teeth cast silver caps were made after releasing the surface of the inlay with tinfoil. Wear on the restorations was simulated by grinding away some gold from the inlay. Silicon impressions of the teeth were made with the caps both before and after this simulation. The volume and the average thickness of the removed gold was measured from the weight of the enclosed impression material in the cap before and after the wear simulations, the density of the tinfoil and the impression material as well as thickness and the weight of the tinfoil‐release.Values expected for the volume and the average thickness of the removed gold were calculated from the weight of the restored acrylic teeth before and after the wear simulation, the weight, the density and the thickness of the tinfoil and the density of the gold used for the inlays. Measured and expected values are linearly correlated (r=0.97). An average wear thickness of the occlusal surface of a particular tooth of at least 30 μm can be detected. Because of its simplicity, inexpensiveness and accuracy the wear measurement method is highly productive and suitable for large scale and long‐term clinical research on the wear behaviour of posterior compos

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1985.tb00615.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryDissection of seven cadavers showed that the platysma muscle may cover large parts of the masseter muscle. The platysma may thus be a significant source of artefact activity when recording the masseteric activity with surface electrodes. This is illustrated by a patient‐case.The electrical activity of the platysma muscle was studied during jaw movements in normal, healthy subjects. Activity was regularly recorded during the latter half of large vertical jaw opening movements and, in five of the seven subjects, in the ipsilateral platysma muscle also during combined lateral–vertical jaw opening movements. The platysma may, therefore, in some individuals, have a functional role during the opening phase of chewing cycles when this has a marked lateral compon

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1985.tb00616.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryA computer‐controlled apparatus is described for the measurement of the preferred vertical dimension of occlusion (PVDO). The proposed apparatus guides the dentist through the measuring process and calculates the measure of the PVDO from the observations mad

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1985.tb00617.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryAn electron microprobe was used to investigate the composition and microstructure of the reaction zone occurring around experimental particles of approximately Ag‐Cu eutectic composition in two experimental dental amalgams. This study formed the basis for the examination, described in a subsequent paper, of the reaction zones in several commercially available amalgams. Techniques of phase composition analysis were further developed in order to identify and quantify the component phases in the regions of the reaction zone. The clumped, outer, more darkly shaded region of the zone contained predominantly η1(Cu6Sn5) phase. The inner, more lightly shaded region of the reaction zone was found to contain substantial quantities of η1, γ1, a Cu‐Hg phase and a Ag‐Cu c

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1985.tb00618.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryAn electron microprobe was used to investigate the composition and microstructure of regions in the reaction zones around particles of approximately Ag‐Cu eutectic composition in commercially available and experimental dispersion modified amalgams. Two distinct regions were identified. Techniques of phase composition analysis were further developed in order to identify and quantify the component phases present in the two regions. The outer, somewhat clumped region contained principally a network of strands and particles of η1(Cu6Sn5) composition and some γ1phase. After phase composition analysis, the inner region was found to contain η1phase and substantial quantities of γ1phase, a Cu‐Hg phase (probably Cu4Hg3formulation) and unreacted Ag‐Cu. The two regions may be best described as η1‐rich and η1‐spars

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1985.tb00619.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryChewing motor performance was examined in twenty‐one patients. Twelve patients had TMJ dysfunction syndrome, eight had occlusal trauma, and one had CNS impairment. Surface electromyography and three‐dimensional jaw movement was recorded. Discomfort was recorded by the patient during chewing of beefstick. Specific changes in mandibular movement were related to the presence of pain, discomfort and other symptoms of the TMJ dysfunction syndr

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1985.tb00620.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryThe fracture toughness (KIC) has been measured (at 1 week) for a selection of sixteen amalgam products. This included low copper (i.e. Cu<6%) and high copper (both single component and admixed) products in milled and spherical powder forms. The results have shown that the fracture toughness decreases progressively as the copper content increases. The admixed high copper products possess superior fracture toughness to those containing a single component powder. These results have been attributed to differences in the microstructures produced by changes in composition and form in which the copper addition is made.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1985.tb00621.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryA numerical method for speech analysis has been developed. The method is based on sounds spectrograms as carriers of information about individual voice characteristics.The effects on speech sounds caused by alterations of the oral cavity dimensions with complete dentures of different morphology were analysed. Different positions of upper incisors and different thickness of the denture palatal plate were used as changeable factors in the longitudinal and transverse dimensions of the oral cavity. The effects of these changes on the relative duration of separate sounds in a word and the patient adaptation period were also analysed.From the results some conclusions of pragmatic value were obtained useful in the clinical procedures of denture construction.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1985.tb00622.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryFew studies have reported the maximum potential of surfaces to adsorb the cationic antiseptics and few comparisons between antiseptics have been carried out. The purpose of this investigation was to measure the maximum uptake of alexidine, cetyl pyridinium chloride, chlorhexidine gluconate and chlorhexidine acetate to polymethylmethacrylate and by the construction of adsorption isotherms determine the pattern of molecular attachment to the recipient surface. The mean maximum adsorption findings for these antiseptics demonstrated significantly greater uptake of cetyl pyridinium chloride than the other antiseptics and significantly less uptake of alexidine compared with the other antiseptics. All four antiseptics showed a Langmuir type adsorption isotherm consistent with the formation of a monolayer of molecules on the recipient surface. For chlorhexidine preliminary studies demonstrated that the pattern of adsorption was not altered by saliva pre‐treatment of surfaces. No evidence of molecular multilayering was observed even at higher concentrations of the antiseptics. However, the maximum uptake on to the surface was significantly increased when no post‐treatment washings were carried out. It was concluded that this increased uptake would be unlikely to play an important role in antiplaque activity because of its relative instability. The pH dependency for the adsorption of these antiseptics was demonstrated such that as previously observed for chlorhexidine gluconate at low pH adsorption is almost completely, or completely, preven

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1985.tb00623.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY