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At least 19 recordsLinked to original sources

The relationship between maximal bite force, bite force endurance, and facial morphology during growth. A cross-sectional study.

The aims of this investigation were to study the relation between facial morphology and bite force at different ages during growth and to investigate possible relations between bite force and the variables age, finger force, stature, and sex in growing healthy individuals. One hundred and thirty-six individuals were included, consisting of six groups of males and females, 7-9, 10-12, and 20-24 years old. Standardized photographs were taken to determine the facial type. The occlusal relationship, body height, finger force, maximal bite force, and bite force endurance amplitude were recorded. All bite force variables and finger force increased with age in both sexes. A positive correlation was found between the maximal bite force in the incisor region and the ratio of upper to lower facial height; this is, subjects with a high bite force had a relatively short lower anterior height. The maximal bite force for molars and endurance amplitude were positively correlated to stature and finger force but not to facial characteristics. A longitudinal study to follow each individual child during growth would be of interest to evaluate the importance of muscular influence on facial growth.

Adult↗

Individual differences in perceived pinch force and bite force.

Six subjects made cross-modal matches of pinch force and bite force to an electrocutaneous stimulus. The electrocutaneous stimulus consisted of bursts of pulses, and the intensity of the stimulus was varied by changing the number of pulses per burst. All of the individual matching functions were fit well by power functions. The scaling constants and exponents of the power functions covaried systematically with the maximum pinch force for 5 of the 6 subjects. The relationship was consistent with the hypothesis that subjects perceive their physical maxima equally, in agreement with Borg's theory of relative perceived exertion. For both pinch force and bite force functions, the scale factors could be described by a single linear function of the exponents, suggesting that all of the matching functions converged at a single point with extreme values.

Adult↗

Effects on human maximum bite force of biting on a softer or harder object.

A recent study concluded that the pulps of human incisor teeth may contain mechanoreceptors. These provide the input for a protective mechanism that reflexly limits the maximum bite force by monitoring the stress on compressed dentine. In separate experiments it was later shown that individuals can accurately detect whether they are biting on a harder or softer surface when it seemed that the only receptors which could have detected the difference must have been in the tooth pulps. Thus, pulpal mechanoreceptors may be used subconsciously to limit the maximum bite force and consciously to detect differences in hardness. If these conclusions are correct the maximum bite force should be larger when incising on a soft (rubber) surface than on a hard (acrylic) surface because when the teeth sink into the rubber the bite force is spread over a larger area, thereby reducing the local stress. A reduction in stress allows an increase in bite force. But if the tooth were previously covered with an acrylic crown, which would already reduce the stress by distributing the bite force over a large area of the incisor crown, there would be little or no difference in the maximum bite force whether biting on rubber or acrylic. The results of experiments on 15 participants confirm these predictions and support the hypothesis that the pulps of human incisors contain high-threshold mechanoreceptors.

Adult↗

Influence of chin tap force and bite force parameters on the duration of the electromyographic silent period.

Controversy exists as to whether chin tap force and bite force affect the duration of the electromyographic silent period following the jaw jerk reflex during isometric contraction of the elevator muscles of the mandible. This study demonstrates that statistical trends exist showing increased silent period duration for increased tap forces and decreased silent period duration with increased bite forces.

Adult↗

A novel bite force recorder and maximal isometric bite force values for healthy young adults.

Human bite forces have been studied with several types of equipment, and the maximal values reported have varied greatly. In the present study, a new bite force recorder was developed to measure human bite forces. When measuring maximal bite force, the mandible is, laterally and sagittally, almost in the intercuspal position, while the vertical opening of the jaws in the molar region is about 14 mm. Several teeth bite upon the housing. A quartz force transducer serves as a sensory unit. A microprocessor produces a numeric result, shown on a liquid crystal display (LCD). In order to adapt the sensor to be a part of a bite force recorder, we designed a unilateral housing of nonhardened tool steel. In laboratory calibration tests, a series of loads from 112.8 to 1691.5 N was used. The maximal bite forces of healthy undergraduate dental students, 15 men and 15 women, were investigated. The results for both genders remarkably exceeded the values previously reported for unilateral housings. The mean maximal bite force value in the molar region was 847 N for men and 597 N for women. The finding that pain or lack of muscular strength most often limited the clenching suggests that the actual masticatory potential was registered.

Adult↗

Bite club: comparative bite force in big biting mammals and the prediction of predatory behaviour in fossil taxa.

We provide the first predictions of bite force (BS) in a wide sample of living and fossil mammalian predators. To compare between taxa, we calculated an estimated bite force quotient (BFQ) as the residual of BS regressed on body mass. Estimated BS adjusted for body mass was higher for marsupials than placentals and the Tasmanian devil (Sarcophilus harrisii) had the highest relative BS among extant taxa. The highest overall BS was in two extinct marsupial lions. BFQ in hyaenas were similar to those of related, non-osteophagous taxa challenging the common assumption that osteophagy necessitates extreme jaw muscle forces. High BFQ in living carnivores was associated with greater maximal prey size and hypercarnivory. For fossil taxa anatomically similar to living relatives, BFQ can be directly compared, and high values in the dire wolf (Canis dirus) and thylacine (Thylacinus cynocephalus) suggest that they took relatively large prey. Direct inference may not be appropriate where morphologies depart widely from biomechanical models evident in living predators and must be considered together with evidence from other morphological indicators. Relatively low BFQ values in two extinct carnivores with morphologies not represented among extant species, the sabrecat, Smilodon fatalis, and marsupial sabretooth, Thylacosmilus atrox, support arguments that their killing techniques also differed from extant species and are consistent with 'canine-shear bite' and 'stabbing' models, respectively. Extremely high BFQ in the marsupial lion, Thylacoleo carnifex, indicates that it filled a large-prey hunting niche.

Animals↗

Swinglock removable partial denture and biting forces in partially edentulous patients. Comparison of individual biting forces with and without swinglock removable partial denture.

Several studies have shown that swinglock removable partial dentures are effective for stability of the abutment teeth and the surrounding tissues including alveolar bone. This efficacy has been thought to be due to the dynamic structure of the swinglock attachment. Individual biting force was measured to determine the physiological efficacy of teeth splints by use of the attachment. The results showed that individual biting forces with the swinglock removable partial denture were 10-25% higher than those without the denture. Furthermore, statistical analysis showed that the individual biting forces with the swinglock removable partial denture were significantly higher. The swinglock attachment can stabilize partially edentulous dentition by splinting all residual teeth. In addition, when physical forces are applied to the abutment teeth and the artificial teeth, this attachment can deliver and distribute the stress to the other abutment teeth and alveolar mucosa. The present findings suggest that the swinglock attachment augments the ability to withstand physical forces such as those occurring during biting and mastication.

Bite Force↗

A thin bite-force transducer with three-dimensional capabilities reveals a consistent change in bite-force direction during human jaw-muscle endurance tests.

The construction of a 2 mm-thick bite-force transducer, capable of measuring the magnitude and direction of a bite force in three dimensions, is described. The transducer is programmed to display the properties of a bite force on a computer monitor. A preliminary study was designed to test its performance. This took the form of endurance tests on three human subjects: the test was repeated on one subject. The direction of a sustained maximum incisal bite force was monitored while subjects clenched for as long as possible on the transducer. The initial bite force was directed about 10-15 degrees forward of the vertical. During the test the magnitude of the bite force was kept roughly constant but, for all four tests, its direction gradually changed until at the failure point it was nearly vertical. The consistency of the results suggests that the transducer is sufficiently accurate to be a useful tool for studying human jaw mechanics.

Acrylic Resins↗

The influence of craniofacial form on bite force and EMG activity of masticatory muscles. VIII-1. Bite force of complete denture wearers.

Today, Japan as a society is aging. The average life expectancy of Japanese people is approximately 80 years. One result of this is that preservation of masticatory functions in elderly people has become increasingly important from the viewpoint of quality of life. In the future, the use of dentures in facilitating masticatory functions as a substitute for teeth that are lost during the aging process will assume greater significance. Accordingly, appropriate evaluation and judgment of complete dentures for edentate jaws is crucial. This study was designed to elucidate the effects of the craniofacial form in complete denture wearers on the mode of activity of gnathic functions. First, subjects wearing complete dentures in both the upper and lower jaws were instructed to carry out vertical clenching, and bite force direction was determined. These data were then related to the subject's craniofacial morphology. These results suggest that the bite force direction in complete denture wearers is not affected by gender differences, but is closely associated with lateral craniofacial morphology, and that appropriate setting of occlusal plane and the occluded vertical dimension is extremely important in the preparation of complete dentures.

Aged↗

Influence of visual feedback on human isometric bite-force tremor.

In contrast to recent reports, during an isometric short forceful bite, visual feedback had a significant influence on the force tremor spectrum. The value of a 'half-value frequency', being the frequency f1/2 at which, with increasing frequency, the amplitude of the spectrum for the first time drops to half its initial value, was used as an indicator for the spectral behavior. Under visual feedback, the amplitude contribution to the force spectrum in the 3-5 Hz frequency range was much larger than after deprivation of visual feedback. Elevations in the frequency range between 3 and 5 Hz in the force spectrum are interpreted as an expression of a visual feedback loop with a tau between 100 and 200 ms. This is supported by the visual/oral reaction times recorded, which were between 110 and 190 ms.

Adult↗

[Surgical corrections of mandibular forced bites].

A forced bite results in displacement of the mandible and malposition of the condyles. The terminal hinge position is a useful point of reference in treatment planning for the surgical correction of forced bites, since it is, among others, independent of the occlusion. Thus, it provides an ideal condyle-fossa relation.

Cephalometry↗

Pathologic attrition and maximal bite force.

The maximal bite force was recorded between antagonizing anterior teeth in a group (n = 10) of patients with pathologic attrition and in a control group. No statistically significant difference between the maximal bite forces was recorded. Also, the effect on the maximal bite force of the continuous wearing of a partial bite raising splint for 4 months was recorded. The great individuality in reaction patterns prohibited simple generalizations. However, in some individuals the maximal bite force was larger when biting on the splint than without, both at base line and after 4 months. Also, the maximal bite force showed a tendency to increase with time. The findings indicate that pathologic attrition is not necessarily associated with a high maximal bite force. Also, the maximal bite force recorded under various conditions is seemingly not an absolute value but rather the result of a number of factors of varying importance for different individuals.

Adult↗

The riddle of the large loss in bite force after fast jaw-closing movements.

In unloading experiments (in which the resistance to a forceful static bite is suddenly removed), it is shown that the residual bite force (when the jaw system is arrested shortly after the unloading) is remarkably small. For example, of a 100-N initial bite force, only 18 N is left after a jaw travel distance of 5.0 mm. The present experiments were designed to study whether the magnitude of the low residual bite force is dependent on the initial bite force, the initial degree of mouth opening, and the distance of jaw travel. Furthermore, we analyzed whether the low magnitude of the residual force can be attributed to reflex events of the jaw muscles or to the force-length properties of the jaw-closing muscles. It was found that the residual forces are largely dependent on the distance of jaw travel and are barely sensitive to variations in initial mouth-opening. The relative residual forces are independent of the magnitude of the initial bite force. The maximum residual forces are on the order of 25% of the initial bite force after a jaw travel of 4.5 mm. The low values of the residual forces cannot be attributed to reflex events, because it took about 80 ms for the masseter muscles to decrease their force to a 50% level after their excitation was switched off. Furthermore, it was shown that the force-length properties of the jaw-closing muscles are not responsible for the small values of the residual forces, since over the trajectories used in the present experiments, the sarcomere lengths of the jaw-closing muscles were beyond their optimum. It is suggested that the low residual forces are brought about by (1) a non-uniform sarcomere behavior of the jaw-closing muscles when contracting, or (2) a long-lasting change in the myofilament system of the closing muscles induced by the sudden shortening of muscle fibers.

Biomechanical Phenomena↗

Influence of clenching intensity on bite force balance, occlusal contact area, and average bite pressure.

It has been difficult for investigators to simultaneously and reliably evaluate bite force in the intercuspal position with the area and location of occlusal contacts. This study was designed to investigate the variations in these parameters with respect to two factors: three levels of clenching and the preferred chewing side. Human subjects with normal occlusion were examined with a recently developed system (Dental Prescale Occluzer, Fuji Film, Tokyo, Japan). The three levels of clenching intensity were assessed by masseteric EMG activity and included the maximum voluntary contraction, and 30% and 60% of the maximum. The results indicated that the bite force and occlusal contact area on the whole dental arch increased with clenching intensity. In contrast, the average bite pressure, obtained by dividing the bite force by the contact area, remained unchanged regardless of the clenching intensity. As the clenching intensity increased, the medio-lateral position of the bite force balancing point shifted significantly (P<0.01) from the preferred chewing side toward the midline. The antero-posterior position remained stable in a range between the distal third of the first molar and the mesial third of the second molar. The bite force and occlusal contact area, which were mainly on the molars, increased with the clenching intensity, whereas the proportions of these two variables on each upper tooth usually did not change significantly. The exception was the second molar on the non-preferred chewing side. When comparisons were made between pairs of specific upper teeth of same name, usually no significant difference was found in bite force or occlusal contact area, regardless of the clenching level. Again, the exception to this observation was the second molar on the preferred chewing side, which had a larger area at the 30% clenching level. The results in normal subjects suggest that as the clenching intensity increases in the intercuspal position, the bite force adjusts to a position where it is well-balanced. This adjustment may prevent damage and overload to the teeth and temporomandibular joints.

Adult↗

The effect of periodontal surgery on bite force, occlusal contact area and bite pressure.

BACKGROUND: Tooth mobility resulting from the loss of periodontal support or trauma induced by periodontal surgery may change the amount of bite force (BF) and bite pressure (BP) and number of occlusal contact areas (OCAs). The aim of the authors' study was to compare BF, BP and OCA of teeth with periodontal disease before and after periodontal surgery with similar values of healthy teeth. METHODS: The authors performed quantitative analysis of BF, BP and OCA using a pressure measurement film. Ten patients with periodontitis who needed periodontal surgery served as the test group. The authors took measurements of BF, BP, OCA and mobility (using Miller's Mobility Index) just before surgery and at one, four and 12 weeks after surgery. They also measured clinical attachment levels (CAL) before surgery and 12 weeks after surgery. Ten subjects without periodontitis served as the control group. RESULTS: Although BF and OCA increased the first week after periodontal surgery, analysis of variance (ANOVA) showed no statistically significant differences at a 95 percent confidence interval. There were statistically significant differences between first-week mobility and that at four and 12 weeks (P = .001). A factorial ANOVA showed significant interaction between BF and mobility (P < .05). CONCLUSIONS: The authors' findings suggest that changes in BF, BP and OCA were not affected by periodontal surgery. However, mean mobility values and BF are correlated. Further investigations of this measurement method involving larger study populations and a longer follow-up period are needed. CLINICAL IMPLICATIONS: It seems to be helpful to follow occlusal changes after periodontal surgery using a pressure measurement film. It also may be suggested that this measurement method could be used to evaluate the treatment prognosis.

Adult↗