摘要:

summaryFissure sealants have been used successfully as a means of preventing fissure caries. This effectiveness is directly related to sealant retention and retention is dependent upon a meticulous method of application. The aims of this study were to determine if sealant adhesion and penetration were affected by the variation in preparation of the enamel surface, or by pretreatment of the enamel surface with dentine adhesive systems, in fissures of varying morphology. Non‐carious posterior teeth were visually examined and sorted according to fissure type, classified as shallow, deep or intermediate. Occlusal fissures were sealed using one of six methods, thermocycled for 200 cycles between 5 and 55°C, in artificial saliva, then placed in a 1.5% procion orange dye for 3 min. Teeth were sectioned bucco‐lingually and examined with a light microscope for (i) penetration of the sealant into the fissure pattern and (ii) adhesion of the sealant. All sealant techniques employed in this study adapted well to the enamel surface as the 1.5% procion Reactive orange dye failed to penetrate any of the sealed tooth sections. Shallow fissures were well obturated in both lateral and vertical dimensions. Sealants adapted well to the vertical walls at the orifice of deep fissures but generally failed to penetrate into the deeper aspects. Reducing the etching period with 37% phosphoric acid resulted in increased voids between the sealant and enamel surface and poorer adaptation to the vertical walls. The addition of dentine adhesive systems, Scotchbond Multi‐Purpose and All‐Bond 2, enhanced the vertical penetration of the sealant, particularly in deep fissures. It is proposed that the dentine adhesive systems may improve the retention rate of sealants in deep fissures particularly if the fissure is not completely dry prior to resin p

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1996.tb00836.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

summaryIn 46 non‐patients and 46 patients, the authors examined the presence (+) and absence (‐) of canine tooth guidance (CG), i.e. dynamic dental articulation events in contrast to static dental occlusion events. During a right and a left laterotrusion of the mandible, the number of simple, mutually exclusive and exhaustive tooth guidance events (possibilities) was four. In addition, the authors examined the associations between temporomandibular joint (TMJ) sounds and canine guidance events. In non‐patients, CG+ was relatively infrequent (30%), and CG‐ was relatively frequent (70%). In patients, CG+ was relatively infrequent (22%), and CG‐ was relatively frequent (78%). In both non‐patients and patients, bilateral CG+ was rather infrequent (15%). In both nonpatients and patients with the presence of TMJ sounds, CG+ was relatively infrequent (38%) while CG‐ was relatively frequent (61%). In non‐patients as well as patients, no evidence was found that distal CG+ (putative lateral retrusive guidance) was associated with ipsilateral TMJ sounds (relative risk = 0%), nor that the association between mesial CG+ (putative lateral protrusive guidance) and ipsilateral TMJ sounds was beyond that of mere chance (relat

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1996.tb00837.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

summaryAveraged reflex responses in the masseter muscle to transverse taps delivered to the upper central incisor were studied in 13 patients with chronic arthritic temporomandibular joint (TMJ) disease (arthritis group) and 28 patients having internal TMJ derangement (derangement group). The diagnostic assessment of TMJ disease was based on a combination of imaging methods. Fourteen symptomfree subjects served as a control for the electromyographic observations. The tapping force was increased in steps from 0 25 to 6 N. The pattern of the reflex response consisted of various inhibitory and excitatory waves, which were found to change with increasing tapping force. The first inhibitory wave (I‐l) increased in duration with increasing tapping force in all subjects. At certain tapping forces, I‐l was of signiflcantly lower amplitude and longer duration in the arthritis group than in the control group, but latency and threshold did not differ. The excitatory wave seemed to have longer latency and higher amplitude in the arthritis group than in the control subjects at some tapping forces. In summary we conclude that the pattern of the reflex response seemed to be similar in patients with different TMJ disorders and in symptomfree subjects. Only the level of inhibition, duration of I‐l and higher excitatory response, might separate the patients with arthritic TMJ disease and internal TMJ derangement from symptomfree subjects, but no specific differences between the groups could be

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1996.tb00838.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

summaryDetails are presented of the reaction of multiple prosthetic experts in 17 dental schools in the U.K. to 125 design rules for removable partial dentures. Those rules receiving support from 50% of the schools are candidates for inclusion in RaPiD, a knowledge‐based assistant for the design of removable partial denture

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1996.tb00839.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

summaryThe influence of the composition and the casting process upon the electrochemical corrosion of a selection of palladium‐based alloys and nonprecious metal alloys has been investigated in vitro using an electrochemical method. No influence of the casting process upon the corrosion resistance was observed with palladium‐based alloys. Changes in the crystallographic structure effected by the different composition of the alloys were found, the casting process did not cause significant effects. With nickel‐chromium alloys rather low corrosion stabilities were obs

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1996.tb00840.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

summarySeries of four open‐close, protrusive and lateral movements were recorded by the six degrees of freedom jaw movement recording system OKAS‐ 3D in 20 healthy subjects. Consequently the movement paths of nine condylar points, the palpated lateral pole and eight points located on a square parallel to the sagittal plane with an edge of 10 mm and centred around the lateral pole were calculated. For all movements except the protrusive movements, the 3‐D excursions of the condylar points strongly depended upon the choice condylar reference point (ANOVA, P<0 001). During laterotrusive movements the Bennett angle and the Bennett shift also varied significantly according the position of the reference point (ANOVA, P<0 001). The results of this study underline that comparison of condylar movements between different studies only possible when the same condylar reference point is used. General consensus on the choice condylar reference point is thus n

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1996.tb00841.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

summaryThis paper describes the modulation of human deliberately unilateral mastication by trigeminal and extra‐trigeminal standardized painful stimuli. Series with 15 s of gum‐chewing before induction of pain, during pain and after pain were quantitatively assessed by jaw‐closing muscle electromyography (EMG) and kinematics of the lower jaw. Four different painful stimuli were used: cold stimulation of the frontal region, cold stimulation of the dominant hand, capsaicin stimulation of the hard palate, and pressure painm stimulation of the temporomandibular joint (TMJ). Intensity and quality of perceived pain were rated on visual analogue scales (VAS) and McGill's Pain Questionnaires (MPQ). Analysis of the data showed that frontal cold stimulation was the least painful test and was associated with the fewest changes in masticatory function. Cold stimulation of the hand and palatal capsaicin stimulation caused significant increases in peak amplitudes of EMG bursts from all jaw‐closing muscles and faster jaw movements whereas TMJ pressure pain produced significantly lower peak EMG amplitudes. The present results suggest that nociceptive input from different tissues and even extra‐trigeminal regions may modulate trigeminal motor function in selective ways. Thus, clinical observations of changes in masticatory function may not always be due to pain in the orofacial region and therefore do not necessitate orofacial

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1996.tb00842.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

summaryA new system for measuring threedimensional deformation has been developed. The main components of the system are a fixed TV camera and vertically scanning projectors. The advantages of the system are: (1) since there is no mechanical contact between the object and the sensing unit, hardness and form of the object do not have to be considered; (2) the system does not need any precise geometry except for the reproducibility of the vertical scanning stage; (3) the time required for one measurement is extremely short; and (4) the system is not expensive. From the basic experiments for testing accuracy, this system has about ± 30 μm range deviation against 1000 μm deformation of the object. The system has been applied to investigate the influence of various impression procedures for a removable partial denture on the displacement of the simulated soft mucosal tissue. It is revealed that deformation forms are expressed precisely. Our results suggest that this measurement system is quite useful for research in dentistry and that it could be widely appli

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1996.tb00843.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

summaryThe radiographic condylar findings of 293 old people (76,81 and 86 years old) were investigated using panoramic radiography. One hundred and twenty four subjects were clinically edentulous, and 169 had at least one natural tooth left. Condylar findings were observed in 16% of the edentulous subjects, and in 25% of the dentate subjects. Over 95% of the findings were radiographic signs often associated with osteoarthrosis. Condylar findings were more common in edentulous women (18%) than in edentulous men (9%) (P<005). Imbalanced occlusion was assessed using the Eichner index. This index describes the existing occiusal support zones. dividing the dentition into three main classes. When natural dentition and fixed constructions were included 70% of the population had no occiusal contacts. With removable dentures included, class A (contacts in four support zones) represented 74% and class C (no occiusal contacts) 4% of the subjects. Three per cent of the men and 0.5% of the women had no occiusal contacts even then. Imbalanced occlusion showed no association with condylar findings; neither were there any significant differences in the condylar findings between the sexes in the dentate subjects, between the age groups, or between the dentate and edentulous groups.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1996.tb00844.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY