摘要:

SummaryThe extent and directions of movements of spring bridge abutments were studied on acrylic casts with resilient steep and shallow palates and containing human molar and premolar abutments with compressible ‘periodontal ligaments’. Bridges with rigid bars and ‘flexible’ standard, long and short lengths were cast in Type IV gold, and soldered to Type III gold retainers which were pinned to the abutments. The pontic on each bar was depressed a standard 0.2 mm, and the movement of the abutments registered on a dial gauge resting against the mesio‐buccal corner of each retainer. The combination of bar length and palatal contour causing least movement of an abutment was the shortest bar to the molar abutment in the shallow palate model; indeed all bars on this model deflected the molar abutment less than similar bars on the steep palate model. Differences in palatal contours did not affect the extent of movements of the premolar abutments which were comparable to molar movements in the steep palate model. Abutment teeth moved mesio‐buccally when the pontic was depressed, and the elbow of the bar usually moved off the palate indicating the fulcrum was positioned along the anterior section

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1983.tb00104.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SummaryIn a sample of fifteen partially edentulous subjects assigned for immediate complete denture treatment, a correlation analysis was performed between pre‐extraction facial morphology determined from lateral cephalograms, and EMG activity of the anterior temporal and masseter muscles in maximal clench and tapping of teeth. Marked correlations observed between vertical and sagittal jaw relations and mean voltages of the jaw‐closing muscles indicated strong biting activity in subjects with a square facial type. No significant associations were observed between biting strength and the age of the subjects.Correlations between facial morphological changes and changes in EMG biting activity after denture insertion and during 1 year of denture wear indicated that the anterior temporal muscles were extremely sensitive to sagittal changes in anterior occlusion. The masseter muscles were less sensitive, but responded in some instances to changes in vertical jaw relations

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1983.tb00105.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SummaryPotentiodynamic cyclic polarization of four orthodontic alloys (wires), namely Permachrome, Elgiloy, a β‐titanium alloy and Nitinol in a 1 % NaCl solution within −500 mV and +300 mV (SCE) indicated the first three alloys to be passive whereas breakdown of passivity was observed on Nitinol. The SEM examination of the pre‐and post‐polarized alloy surfaces provided evidence which was consistent with the electrochemical measurements, in that the first three alloys exhibited no appreciable corrosion damage whereas pitting corrosion was observed on Nitinol.The results obtained from X‐ray analysis of the pitted surface indicated that this pitting could be due to selective dissolution of nickel fr

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1983.tb00106.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SummaryA group of ten edentulous patients, who had experienced persistent soreness of the mucous membrane underlying their lower dentures, have been shown to exhibit a tendency towards greater activity of the temporal muscle while ostensibly at rest, compared with a number of normal subjects. A biofeedback technique, based on electromyography, proved effective in teaching the patients to relax during an experiment of approximately 20 min duration. In contrast relatively little change could be achieved by the normal subjects. It is concluded that the results support the hypothesis that muscle tension may contribute to lower denture discomfort, and suggest that biofeedback muscle relaxation training may be a useful method of treatment in such cases.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1983.tb00107.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SummaryMechanisms of fatigue failure in polymers and the aims of fatigue testing have been examined, and factors affecting testing summarized. In the light of available work in several fields, parameters have been suggested for realistic flexural fatigue testing of denture base resins. A testing machine has been developed, with which the changes in properties of acrylic resin after fatigue in different environments can be studied. These changes developed gradually after 104 cycles and were related to the development of bulk crazing rather than to thermal effects. The amount of decay in the elastic modulus was not such that the material could have been said to have ‘failed

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1983.tb00108.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SummaryA punch method for sampling the cavity wall/material interface for microbiological culture is described. Good correlation was obtained between the recording of micro‐organisms by this method and from histological section

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1983.tb00109.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SummaryThe physical removal of plaque from dentures by brushing is important in the maintenance of oral health. However, there is a danger that brushing will abrade acrylic resin. A machine using a rotary brushing action was therefore utilized for laboratory tests of possible cleaning pastes, employing a toothbrush with good access and adaptability to denture surfaces. Crest toothpaste produced the most abrasion on acrylic resin, Dentu‐Creme the least. An experimental paste produced an appreciably lower abrasion rate. Self‐cured specimens wore more than heat‐cured ones. The rate of abrasion decreased as the temperature was raised. Brushing with water alone, or with a 10% solution of soap, did not produce detectable wear.The wear produced by proprietary cleaners when hand brushing the lingual flanges of dentures and flat blanks of heat‐cured acrylic was also measured. Boots denture cleaning paste produced the greatest abrasion, Dentu‐Creme the least. The wear measured by reference to a glass plane was at least twice that recorded by the decrease in depth of a groove. The machine did not quantitatively produce the same abrasion as hand brushing, nor did it qualitatively rank the pastes in the same order of abrasiveness.The clinical relevance of these results is

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1983.tb00110.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SummaryThe casting of gold on to wrought ‘Wiptam’ and ‘G.T.’ posts has been investigated. Notching of ‘Wiptanm’ posts gave rise to grain structure rearrangement; carbon deposits from the wax burn were retained in the notches and prevented complete filling by the gold. Serious cracks developed from these notches when the core was cast on centrifugally but only slightly when Solbrig's method was used. These cracks explain why ‘Wiptam’ posts occasionally fracture.The above problems were not encountered with the ‘G.T.’ post, which has inbuilt retention channels, and allows a more complete burn out

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1983.tb00111.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

SummaryMyofascial pain dysfunction (MPD) syndrome has received widespread attention in the dental and psychological literature. The present paper considers issues concerning a stress‐related muscular hyperactivity theory of MPD syndrome. A review of the empirical evidence as well as methodological problems evident in these studies has been noted. In addition, definition aspects of stress and a conceptual model of stress in clinical use is presented. A functional analysis of the problem components will help determine a proper treatment protocol for patients suffering from stress‐related myofascial pain. A discussion of the conceptual model for assessment and treatment purposes is presented and its implications for future research no

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1983.tb00112.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY