摘要:

SummaryThe chewing and swallowing activity of jaw‐closing muscles was studies longitudinally in 30 partially edentulous subjects who were provided with an immediate complete upper and a partial lower denture. Electromyographic recordings of the anterior temporal and masseter muscles were obtained during habitual chewing of apple and during swallowing of saliva and water, before final extractions and 7 weeks, 6 months, 1 year and 2 years after denture insertion.At the pre‐treatment stage, when the patients were chewing with a residual anterior dentition, the mean voltages showed low values compared to findings reported in subjects with a complete natural dentition. After 6 months of denture use, the chewing forces showed significant increases in amplitude, and the increased force of contraction persisted to the 2‐year stage.The recordings of swallowing revealed no significant changes in maximal mean voltage during the observation period. However, there was a significant increase in the duration of the swallows after 1 year of denture wearing, which might be related to stabilization of the complete upper denture due to continuing resorption of the maxillary

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1991.tb00060.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryThe spontaneous muscular activity of the masseter and two non‐masticatory muscles, and their activity under conditions of noise and flickering light, were recorded in 30 patients with mandibular dysfunction, and in 25 control subjects. The mood of the subjects during the investigation, and the possible presence of emotional disturbances was evaluated by means of questionnaires. The enhanced muscular activity of the masseter muscle differentiated patients from the control group, although it does not constitute a pathognomic sign. Unilaterality of complaints, and dysfunctions of differing intensity were not reflected in differential EMG findings. One‐fifty of the patients exhibited neck muscle activity occurring simultaneously with the masseter activity. The effect of the applied stimuli on the muscular activity was not homogeneous, leading to activation in some cases and inhibition in others. Symptoms of anxiety could be observed in seven TMJ patients. Anxious patients showed higher levels of muscular activity and emotional irritability during the experiment than non‐anxious pat

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1991.tb00061.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryThe aim of this study was to assess the caries incidence and plaque accumulation in schoolchildren at caries risk, after brushing the teeth fortnightly with gels containing 0, 0.4% F, 1.25% F as amine fluoride (AmF) or the common amine fluoride toothpaste containing 0.125% F. The study was conducted double blind over an 18–month period, and after 6 months discontinuation of brushing. Only the group that brushed with the 1.25% AmF gel showed a significant decrease in caries development compared to the group that brushed with the 0.125% AmF toothpaste. During the 6‐month discontinuation period, the incidence of caries increased in all groups: the differences in caries development between all groups were not significant. Plaque indices were significantly lower in the AmF‐treated groups. The highest fluoride concentration in the gel reduced the development of caries to zero, probably due to increased fluoride levels in the oral milieu of caries risk children. In order to maintain a positive effect of fluoride over an extended time period, caries‐prone subjects should continue an initiated fluoride pr

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1991.tb00062.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummarySurgical removal of the head of the condyles inevitably leads to radical redistribution of loads applied to the mandible. The nature of this redistribution can have important implications on the surgical approach and subsequent reconstructive procedures. The purpose of this investigation was to visualize photoelastically the functionally delivered stresses after high condylectomy surgery. Three identical models of a dentate human mandible were constructed from a photoelastic material. One mandible simulated a unilateral and the other simulated a bilateral high condylectomy. The third mandible had both condyles intact and served as basis for comparisons. Silicone implants were placed on the sectioned condylar heads. The condyles, with the silicone implants, were fitted into simulated fossae and the mandibles were loaded unilaterally and bilaterally. The resulting stresses were observed and photographed in the field of a circular polariscope.Substantial differences in load‐generated stresses were observed as a result of both unilateral and bilateral condylectomies, compared to the normal case. The most severe stress conditions occurred with the unilateral condylectomy, where stresses associated with torsion were most eviden

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1991.tb00063.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryThe characteristics of the masseter reflex evoked by tapping a maxillary incisor were compared with the reflex pattern evoked by tapping a corresponding denture tooth after insertion of an immediate denture. Up to three inhibitory phases (I‐1, I‐2 and I‐3), followed by excitation, were found on an averaged EMG. The tapping force threshold for the early inhibitory phase was lower than for the late phases. The pattern of the reflex was generally the same before and after insertion of the denture, but the threshold values increased. After insertion of the denture, the threshold for I‐1 increased from 1±0.3N to 2.2±0.4N, the threshold for I‐2 increased from 2.4±0.8N to 3.8±0.9N, and the threshold for I‐3 increased from 5.1±0.6N to 8.3±0.9N. The latency period for I‐1 also increased from 12.3±0.5 ms to 13.1±0.3 ms after insertion of the denture. After relining, the threshold for evoking I‐1 decreased from 2.7±1.2N to 1.2±0.6N. It was assumed that the mechanoreceptors situated in the mucosa under the denture base could take over the functional role of the periodontal mechanoreceptors for evoking the masseter reflex during tapping, and that these afferents probably had connections

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1991.tb00064.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryThe behaviour of amalgam beam specimens subjected to a sub‐modulus of rupture load at 37°C was compared in static and cyclic modes. Testing was performed using identical equipment, with cyclic testing conducted by intermittent load application for both tests. The specimens tested exhibited varying degrees of deformation and times to fracture in both tests. The mode of load application, either cyclic or static, did not appear to have a significant effect on the degree of amalgam deformation or time to fracture. The most important factors relating to deformation are time of total load application, creep of the specific amalgam and temperature of testi

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1991.tb00065.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryComposite resin bite‐raising splints were fabricated on both sides of the upper jaw in rats. EMG activity of the deep masseter muscle was monitored continuously for 24 h before and up to 4 weeks after treatment. Together with the EMG activity, measurements of the neuromuscular junction area and muscle fibre histochemistry were made. EMG activity showed great variability immediately after splint fabrication. Some of the animals showed increased EMG activity, while others exhibited less activity 48 h after splint application. Overall, the fluctuation lasted for about 4 days, and after approximately 7 days all the animals exhibited decreased EMG activity, followed by a gradual increase in activity towards baseline levels. The neuromuscular junction territory increased significantly 5–10 days after splint application. Histochemical characterization of the deep masseter muscle revealed that it contained the three main types of muscle fibre: slow oxidative (SO), fast‐oxidative‐glycolytic (FOG) and fast glycolytic (FG). The frequency distribution of fibre types did not change after bite‐raising splint treatment. These findings indicated that splint treatment in rats is effective in reducing EMG activity, while the muscle type characteristics remain stable. The effect of lower activity on the motor end‐plates suggested that the neuromuscular junctions are quite sensitive to functio

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1991.tb00066.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryRods of a visible‐light‐cured dental composite resin were photo‐polymerized and immersed in water at 37°C for 7 days. The residual monomers (TEGDMA and Bis‐ GMA) trapped in the set composite and those eluted into water were analysed by gas‐liquid chromatography. It became evident that minor amounts of the residual monomers dissolved in water, but that most residual monomers remained in the set composite. Extension of the irradiation period contributed to the significant reduction in the residual monomer level and its elution

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1991.tb00067.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryVarious desensitizing agents have been used in clinics to solve the problem of dentinal hypersensitivity (DH), but none of them has been shown to be consistently effective. We here introduce a new type of desensitizing agent, i.e. 4% magnesium sulphate with iontophoresis at 2mA for 3 min. These optimal conditions were determined by animal experiments, while only a minor effect on dentinal issues was observed within 4 weeks after the treatment. When this desenistizing agent was used to treat DH, the cure rate of 62.4% remained steady within the 25‐week observation period, while some effect was achieved in all the subjects who participated in the stud

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1991.tb00068.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY