The maximal bite force and the strength of the finger-thumb grip of 125 Skolt Lapps, aged 15 to 65, was measured with a specially devised apparatus. The bite force was measured with the biting fork placed between the first molars and between the incisors, respectively. The finger-thumb grip was measured by letting the subject press the prongs of the fork between the thumb and forefinger of each hand as hard as possible. The range of inter-individual variation of the maximal bite force and finger-thumb grip was great. The mean values were higher for the males than for the females. In the males the maximal bite force thus measured in the molar region was 39 kg (382 N) and 18 kg (176 N) in the incisor region. The corresponding values for the females were 22 kg (216 N) and 11 kg (108 N). The finger-thumb grip strength for males was, on the average, 10 kg (98 N); that of the females, 7 KG (69 N). The average difference in bite force between the men and the women was larger in the group with natural teeth than in the one with complete dentures. The values found for the bite force decreased with increasing age, especially for the females. Most of this reduction with increasing age was probably due to the age-dependent deterioration of the dentition. In both sexes the bite force was notably smaller among the denture wearers than among the dentate persons. The number of natural teeth varied closely with the bite force, i.e. the greater number of natural teeth the greater the bite force.

Chewing efficiency, defined as the ability to grind a certain portion of a test food during a given time, was tested in 139 Skolt Lapps, ages 14-65. 94 persons had natural teeth and the remaining 45 wore dentures (partial and/or complete). The test food was almonds. Number of chewing strokes, swallowings and chewing time was denoted. The chewing efficiency was classified after a scale from 1 to 5 where 1 meant very good and 5 very poor ability to reduce the particle size of the test food. Clear associations were found between chewing efficiency and dental state. Number of occluding pairs of teeth was closely correlated with chewing efficiency and individuals with less than 20 teeth had a higher index score than those with more than 20 teeth. The values noted for number of chewing strokes, swallowings and chewing time were smaller for those with a good chewing efficiency, but the variation was not linear and not always significant. Denture wearers had statistically significantly higher chewing efficiency score than those with natural teeth, without dentures, and needed more chewing time before swallowing.

In thirty patients (24 women and 6 men) treated because of dysfunction of the masticatory system at the department of Stomatognathic Physiology, University of Gothenburg, bite force was registered before, during and after treatment had been completed. In the controls, thirty-six dental students and trainee dental nurses, with no dysfunction of the masticatory system, bite force was registered on two occasions. Bite force was measured between the first molars on each side and between the central incisors. Also finger force was registered. The force measurements were made at five different levels, increasing from very weak to maximum force. Repeated tests of bite force in the control group, made at intervals of about 1 week, gave almost identical results. Bite force in the patient group was lower than in the control group at the first registration but increased with palliation of the symptoms during treatment. There was no significant difference in bite force between the affected and the unaffected side.

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Mandibular jaw opening was related with general joint mobility in a non-patient adolescent group. The angular rotation of the mandible at maximum jaw opening was slightly larger in females than in males and significantly larger in hypermobile individuals. No significant relationship between linear measuring of maximal mandibular opening capacity and peripheral joint mobility was found either at active (AROM) or at passive range of mandibular opening (PROM). PROM was strongly correlated to the mandibular length. Clinical signs in the great jaw closer muscles could not be associated to decreased AROM. The mean value of the difference between PROM-AROM (DPA) was 1.2 mm. Frequent clenching and/or grinding was correlated to increased DPA only in hypermobile adolescents (r = 0.49***). Those with DPA exceeding 5mm had all reciprocal clicking.