ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1981.tb00520.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SummaryA comprehensive clinical investigation of amalgam restorations was undertaken to evaluate the performance of ‘high copper’ amalgams and the methods used to examine the marginal integrity of restorations.Six alloys, Aristaloy CR (A), Dispersalloy (D), Indiloy (I), an experimental ‘high copper’ amalgam (E), Tytin (T), and New True Dentalloy (N) as a control, were randomly placed by four operators in 435 Class 1 and Class II restorations. Black and white 1 x photographs were taken at baseline, 6, 12 and 18 months and evaluated using the method described by Mahler&Marantz (1979). In addition, the U.S. Public Health Service system (Cvar&Ryge, 1971) was used at each recall.An analysis of variance based on photographic scoring indicated significant differences (P<0.05) among alloys at each recall. The use of Duncan's multiple range test resulted in two homogeneous subsets at 18 months: D, I, E and T, N, A. Six and 12 months recall data showed a close similarity in the rank order of the six alloys. The U.S.P.H.S. system showed no statistically significant differences between the alloys using the chi‐square test, however, at each recall the rank order was comparable to that obtained with the photograph

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1981.tb00521.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SummaryEight children, mean age of 12 years, exercised maximal voluntary tooth clenching to determine the isometric endurance time of the masseter muscle. The endurance time seemed to depend on psychological and/or physiological determinants. The latter might have been Wedensky inhibition, changes in energy metabolism, progressive fatigue and so‐called muscle fitnes

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1981.tb00522.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SummaryPhysiological tooth movements during mandibular excursions with and without occlusion have been considered. Using electronic and pantographic techniques, anterior guidance and tooth movements during simulated mastication (without a bolus) were investigated.Investigations in the absence of occlusion showed that elastic deformation of the mandible gave rise to tooth movements. During occlusion three‐dimensional tooth movements of up to 60 μm in each direction occurred.Pantographic measurements of anterior guidance showed that each type of occlusion (balanced occlusion, group function and canine protected occlusion) has its own characteristic. Only canine protected occlusion gave values which corresponded to physiological da

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1981.tb00523.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SummaryA three‐dimensional photoelastic model was reproduced from a human skull. The insertions of the superficial and deep portions of the masseter muscle and the temporalis fascia were simulated with leather bonded to the appropriate areas. The following loading conditions were employed: (1) bilateral loading of the masseter muscle; and (2) bilateral loading of the masseter muscle together with a bilateral occlusal load. The stress freezing technique was used to lock the resulting stress patterns into the model skull. The stress trajectories were observed and photographed in a circular polariscope.The results suggest that the major stress trajectories to the zygomatic bone and arch follow an alveolo‐maxillary‐zygomatic‐temporal direction. Stresses were highly concentrated in the zygomatic process of the temporal bone. Generally, the stresses were concentrated in those areas of the bone where architectural reinforcement had been demonstrated by other

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1981.tb00524.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SummaryFour direct filling resins were examined in order to compare the roughness and porosity of different materials, mixed by different methods. From each material six specimens were prepared. Each specimen was formed against a Mylar sheet and the Mylar‐formed surface was examined. Subsequently it was trimmed and polished and re‐examined. Each specimen was examined with a microscope using incident light and employing an automatic point‐counting attachment in order to assess the percentage surface (apparent) porosity. Each specimen was also examined with a stylus‐type profile meter.Rt(total roughness height) was recorded for all specimens andRa(roughness average) was recorded for all polished specimens. The findings support the conclusion thata capsulated resin without an inorganic filler yields a better surface than other

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1981.tb00525.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SummaryIn vitroandin vivoexperimental microleakage around ageing dental amalgam restorations has been reviewed. The methodologies, materials and results were examined and discussed. The initial experimental microleakage which occurred around unlined/ unvarnished dental amalgam restorations and the development of leakage around lined/varnished dental amalgam restorations underlines the problem of attaining a permanent effective seal around dental amalgam restorations. The limitations of microleakage studies have been outlined and the importance of an understanding of the chemical changes which occur in the microcrevices stressed. This understanding may facilitate the production of a lifelong successful dental amalgam restoration and perhaps the development of an anticariogenic amalgam type fissure sealant.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1981.tb00526.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1981.tb00527.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY