摘要:

SummaryCurrent trends in periodontal aspects of restorative dentistry are: (1) Supragingival placement of margins of restorations. (2) Avoidance of overcontoured restoration, and minimal concern with lack of contour. (3) Search for occlusal stability or self‐limited movement patterns of teeth through precise occlusal adjustment and accurate reconstruction of occlusal anatomy in single restorations. (4) Restricted indications for splinting of mobile teeth. (5) Hemisection with fixed bridges in cases of extensive bifurcation involvement. (6) Restricted indications for replacement of lost molars.The purpose of restorative dentistry is to restore and maintain health and functional comfort of the natural dentition combined with satisfactory aesthetic appearance. Thus, all dental restorations should comply with established requirements for periodontal physiology and health, both with regard to surface and functional characteristic

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1974.tb00769.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SummaryThe changes in facial skin temperature during prolonged unilateral chewing were investigated by thermography (AGA Thermovision System, Model 665). An increase in skin temperature over the masseter area was demonstrated, but this was not invariable, and not always over the ‘working’ side. The suggestion is made that prolonged bruxism could result in a continuously raised blood flow within the masseter mus

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1974.tb00770.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SummaryThe relation between muscle activity and facial morphology was studied in twenty‐five boys and twenty‐seven girls, aged 9–11 years. The activity in the anterior and posterior parts of the temporal muscle, the masseter muscle and the upper lip was recorded bilaterally with the mandible in postural position and during chewing, swallowing and maximal bite. The electromyograms were analysed in respect of maximal mean voltage amplitude and the duration of muscle activity. Facial morphology was studied with the aid of profile roentgenograms and model analysis. The activity in postural position was found to be greater in the posterior than in the anterior part of the temporal muscle. The average mean voltage amplitude in the temporal and masseter muscles was greatest during maximal bite, smaller during chewing and smallest during swallowing. In the orbicularis oris muscle the activity was greater during the opening phase of the chewing cycle than during the closing phase.In postural position the activity in the anterior and posterior parts of the temporal muscle were positively correlated. The amplitudes in the anterior and posterior parts of the temporal muscle and in the masseter muscle were positively correlated during chewing, swallowing and maximal bite. The amplitudes in these muscles during chewing were positively correlated with those in the same muscles during maximal bite. During swallowing the amplitude in the upper lip was negatively correlated with that in the anterior part of the temporal muscle.The clearest correlations between muscle activity and facial morphology were found during chewing and maximal bite. During these functions the amplitudes in the temporal and masseter muscles were large in cases with a tendency to parallelism between the jaws bases and between the mandibular occlusal line and the mandibular line. These cases with considerable muscle activity are characterized by rectangular shape of the face in profile and small lower face h

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1974.tb00771.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SummaryFifty young and fifty elderly subjects were tested by a two‐point discrimination method. An aesthesiometer was applied to the facial skin in three different areas innervated exclusively by the ophthalmic, maxillary or mandibular branch of the trigeminal nerve. Two characteristic age differences were disclosed: (1) higher threshold values were found in older subjects, and (2) a greater range of variation in these values was present also among the older subjects. Wale

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1974.tb00772.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SummaryLiterature data was analysed to find the factors which might influence the results of the determination of the dimensional change of dental amalgams during setting, by methods analogous to the test described in ADA Specification no. 1. Included in the paper is a discussion of the different aspects of adaptation of an amalgam restoration to the wall of a cavity. The conclusion was that the ADA dimensional change test is unsatisfactory because its outcome is highly dependent on experimental variables. The experimental problems involved in this test appeared to be unsolvable. A new method to obtain the dimensional change during setting in a clinically relevant way was proposed. This method consists in the determination of the dimensions of preferably cylindrical specimens after setting of the amalgam in a mould.The results are described of the direct determination of the dimensional change by measurement of the diameter of set cylindrical specimens prepared by clinically simulated packing techniques. The dimensional change also was computed from independent measurements of the adaptation. The correlation between the two series of results was determined and compared with the theoretical prediction.A good correlation between both sets of data was established.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1974.tb00773.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SummaryGrowth and remodelling of the mandible and the long bones was studied in rats by triple fluorochrome labelling. Diaphyseal remodelling occurred by apposition at certain areas subperiosteally and at the medullary cavity border. Subperiosteal apposition rate was greatly influenced also by muscle attachment in the mandible, while apposition along selected medullary surfaces corresponded to other mechanical and functional demands. Apposition continued at a moderately slower rate after completion of longitudinal growth. The changing locations of the fiuorochromes appear to confirm the concept that bone tissue is in a constant flow from the apposition surface to deep‐seated areas of osteolysi

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1974.tb00774.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SummaryThe apparatus described is a combined instrument for simultaneous recording of vibrations and EMG activity. It appears to be a useful means of studying reflex mechanisms in the jaw muscles. It is of especial interest as a method of examining the possible effect of vibrations on different receptors, such as the muscle spindles (Matthews, Hannam&Yemm, 1969).The test results presented have indicated a satisfactory method for recording of vibration frequencies, the paper speed required for distinct registration suitable for measuring purposes, and the necessity of pre‐test calibration. They have given proof of the simultaneous onset of vibration and contact pressure al tooth contact as well as the occurrence of increased pressure after tooth contact indicating continual muscle fibre contractio

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1974.tb00775.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SummaryExamination of many different animal dentitions suggests that in those whose function is mastication rather than merely prehension, tooth wear is not only normal but essential to achieve full efficiency. A similar character is found in man among Eskimos and Aborigines where these people live on completely natural diets, and also in Anglo‐Saxon skulls. It is suggested that attrition should be a normal process in the human dentition, and compensatory mechanisms for the loss of tooth substance are discussed. The significance of the unworn cusp in relation to dental and other diseases of Western civilisation is considered, together with the suggestion that sufficient evidence now exists to justify simple cusp height reduction as a prophylactic measur

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1974.tb00776.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SummaryIn this study the finite element method was used in conjunction with an axisymmetric model of an idealized first molar to determine the stresses, as well as deflections in the floor of a cylindrical cavity preparation as caused by condensers of various sizes.It was found that for the 0·25 mm thickness of dentine, the 2 mm condenser and a 2 kg load, a tensile stress of approximately 70 MN/m2was obtained near the centre of the preparation. Under the same load and a 4 mm condenser a tensile stress of only 42 MN/m2was obtained. Bowen&Rodriguez (1962) and Lehman (1967) reported that the tensile strength of dentine was in the order of 51.7 MN/m2and 41.5 MN/m2respectively. Thus it was demonstrated that for certain combinations of load, condenser size, and cavity dimensions, the tensile strength of the dentine in the cavity floor could be exceeded and failure of the cavity floor could ensue

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1974.tb00777.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

SummaryThe procedure is described of an indirect method of recording jaw movement by measuring intervals between electrical pulses generated by a light beam passing two photovoltaic cells attached to the upper and lower jaw. A general description of the basic electronic system is given. An example of registration of the border movement lines of a subject is shown.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1974.tb00778.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY