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Biomedical subjects

B Hedegård

Publications and source records attributed to B Hedegård.

At least 37 records · Page 2Linked to original sources
PubMed1981

Torus mandibularis among Icelanders.

Nine hundred and seventy-six Icelandic schoolchildren (489 male and 487 female) were surveyed for occurrence of torus mandibularis. No sexual dimorphism was observed but there was a statistically significant difference between areas. A highly significant positive association between age and frequency of occurrence and size was also observed. Single tori were more prevalent than multiple ones and also appeared earlier. Symmetrical occurrence predominated, but when unilateral, tori were more often found on the right side. Secular changes in the incidence of torus mandibularis among Icelanders suggest the strong influence of environmental factors.

Adolescent↗
PubMed1981

The silent period in the masseter and the anterior temporal muscles at repeated registrations.

Three dental nurses took part in an investigation of the reproducibility of the EMG silent period. The latency and duration of the silent period after tooth tapping and jaw jerk were found to be rather stable within the same day and between recordings every other day for 10 days. No differences in the SP variables between right and left side were found. Differences in the latency and duration of the silent period between the masseter and anterior temporal muscles during tooth tapping and jaw jerk were registered. The findings suggest functional difference between the two muscles.

Electromyography↗
PubMed1980

An electromyographic study of masticatory and lip muscle function in patients with complete dentures.

The activity of the anterior and posterior portions of the temporal muscle, of the masseter muscle, and of the upper and lower lips was studied with electromyography in 10 individuals with complete dentures. Recordings were made when the patients had old, ill-fitting dentures and 6 months after these were replaced with new dentures. The muscle activity was studied in the postural position of the mandible, during chewing and swallowing of three test foods, and during maximal biting. The maximal tooth tapping rate was also recorded. The postural muscle activity was the same with old and new dentures and comparable with that in patients with natural teeth. The muscle activity during maximal biting was markedly lower than in patients with natural teeth and lower with new than with old dentures. There was no difference in muscle activity between chewing with old and new dentures, but the activity was lower than in patients with natural teeth. This was not compensated for by a longer duration of chewing. The lips were not especially active during chewing in the complete denture wearers.

Aged↗
PubMed1979

Mandibular movements of young adults recorded by intraorally placed light-emitting diodes.

Mandibular chewing movements of 10 young adults were registered with LED. The registrations were performed manually, and the following observations were made: 1. The mean cycle duration was reduced from 1.12 seconds for cycle 1 to 0.76 second for cycle 16. 2. The duration of the opening phase appeared to be shorter than that of the closing phase. 3. The maximal vertical movement of the mandible decreased throughout the chewing period. The results obtained in this study agree with those reported by other investigators and indicate that a system using LED is suitable for analyzing the mandibular movement pattern in clinical situations.

Adult↗
PubMed1979

Tooth loss, prosthetics and dental treatment habits in a group of Swedish men.

Dental history, dental status, the need for prosthetic treatment and dental treatment habits were studied in 389 men aged 21--54 years. The men were selected from a group undergoing military refresher training in the south of Sweden. One percent of the men were toothless. About 3% had full dentures in one or both jaws and an equal percentage had partial dentures. About 3% of the men had bridges in the maxilla and 2% in the mandible. Tooth loss was greatest in the mandibular molar segment, followed by the maxillary molar segment. By means of an index for dental status about 8% of the men were judged to be in great need of prosthetic treatment for aesthetic reasons and/or to improve occlusion. Age, place of birth, educational level and smoking habits were among the factors which seemed to be related to dental status. Seventy percent of the men reported that they went to the dentist once a year, while about 10% seemed rarely or never to seek dental treatment. Dental treatment habits were correlated to place of birth, number of brothers and sisters, edentulousness and the need for prosthetic treatment, among other factors.

Adult↗
PubMed1977

Kinematics of the tooth tapping movement.

Electrical activity in the masseter muscles and tooth contact vibrations were recorded simultaneously from subjects tapping their teeth slowly into maximal intercuspidation and again with maximal frequency. High speed cinephotography was also used with four of the ten subjects. Three main parts could be distinguished on the obtained graphical representation of the tooth tapping movement: tooth contact phase (TCP), opening phase (OP) and closing phase (CP). Tapping frequency was increased by decreasing the jaw opening degree and the durations of TCP, OP and CP. The jaw velocity immediately before tooth contact, which may be of significance for the reflex response, was however not increased. The average jaw speed was nevertheless increased from 10 to 15 cm/s since the turning from OP to CP was more abrupt in high than in low frequency tapping. The duration of electrical activity after tooth contact was significantly shorter at tapping with high than with low frequency. The teeth maintained contact without detectable rebound between each open-close cycle. The OP started about 100 ms after the cessation of electrical activity both at low and high tapping frequency. The time between end of electrical activity and the start of a new OP was supposed to be dependent upon the relaxation time of the masseter muscles.

Adult↗