Jaw separation and maximum incising force

Mackenna, B.R.; ̈rker, Kemal S. Tu

doi:10.1016/0022-3913(83)90404-3

Cited by 61 publications

(43 citation statements)

References 12 publications

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“…With respect to gape, there is a general pattern of decreasing bite force with increasing gape angle both within and between species. The significant, negative association between gape angle and bite E. R. Dumont and A. Herrel (Fig.·1), coupled with data from humans (Fields et al, 1986;Mackenna and Turker, 1983;Manns et al, 1979), suggests that this relationship is common among mammals with generalized cranial morphology. However, the presence of outliers and a relatively low coefficient of determination for the regression (r 2 =0.49) indicate that bite force is also affected by factors other than gape angle.…”

Section: Discussionmentioning

confidence: 79%

“…One study reports that when gape angle is held constant, unilateral bite force increases from canine to second molar positions (van Eijden, 1991). In contrast, when bite point is held constant and gape is varied, there appears to be an optimum gape angle at which maximum forces are produced (Fields et al, 1986;Mackenna and Turker, 1983;Manns et al, 1979). The combination of varying results from human studies and lack of experimental data from non-human mammals leaves the relationship between gape angle, bite point and bite force unresolved.…”

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confidence: 99%

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The effects of gape angle and bite point on bite force in bats

Dumont

Herrel

2003

Journal of Experimental Biology

167

186

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Models of the mammalian masticatory apparatus predict that bite force is affected by both the degree of mouth opening (gape angle) and the location along the tooth row at which force is transferred (bite point). Theoretical analyses of gape angle and empirical studies of muscle function suggest that there is a trade-off between mechanical advantage and gape (Herring and Herring, 1974;Lindauer et al., 1993;Turkawski and van Eijden, 2001). For generalized mammals, larger gape angles require muscles to stretch and are predicted to negatively impact the geometry of their mechanical advantage. Among more specialized taxa, alterations in the geometry of muscle insertions and internal architecture over evolutionary time have resulted in species that can produce high bite forces at high gape angles (carnivores) and other species that are wellsuited to producing high bite forces at low gape angles (herbivores). With respect to bite point, models of the lower jaw as a simple class III lever or beam (e.g. Hylander, 1975;Radinsky, 1981;Weishampel, 1993) and constrained lever models that focus on protecting the temporomandibular joint from tensile loading (e.g. Greaves, 1978;Spencer, 1999) predict that bite forces increase at progressively posterior bite points. Constrained lever models further predict that bite forces level off and may decline posterior to an optimal bite point located at or near the first molar.Despite the widespread use of these models and predictions in discussions of mammalian feeding (e.g. Carraway et al., 1996;Dumont, 1997;Emerson and Radinsky, 1980;Freeman, 1981;Kiltie, 1982;Perez-Barberia and Gordon, 1999;Reduker, 1983;Sicuro and Oliveira, 2002;Stafford and Szalay, 2000), there are surprisingly few experimental data documenting bite force in non-human mammals. Data summarizing maximum bite forces elicited using electrical stimulation are available for macaques, opossums, and rats (Dechow and Carlson, 1983;Robins, 1977;Thomason et al., 1989). Natural, non-stimulated bite forces have been recorded at single (or combined) bite points in possums, hyenas, ferrets and bats (Aguirre et al., 2002;Binder and Van Valkenburgh, 2000;Dessem and Druzinsky, 1992;Thomason et al., 1989). Variation in non-stimulated bite force has been reported only for galagos and macaques (Hylander, 1977(Hylander, , 1979, in which there is a positive relationship between bite force and increasingly posterior bite point.Humans are the only mammals in which the combined effects of gape and bite point on non-stimulated bite force production have been studied in any detail. Even so, the integrated effects of bite point and gape angle on force production remain unclear (Spencer, 1999). Among experiments in which gape and bite point are altered Models of mammalian mastication predict that bite force is affected by both the degree of mouth opening (gape angle) and the point along the tooth row at which force is transferred to a food item (bite point). Despite the widespread use of these models in comparative analyses, experimental data do...

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Section: Discussionmentioning

confidence: 79%

mentioning

confidence: 99%

The effects of gape angle and bite point on bite force in bats

Dumont

Herrel

2003

Journal of Experimental Biology

167

186

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“…From the length-tension curve given by Walker and Schrodt (1973) it can be derived that at a closed jaw tension ranges between about 80% (in the posteriormost region) and 90% (in the anteriormost region) of maximal tension. In the human increase of maximal bite force when the mouth is opened has been observed by Manns et al (1979) and Mackenna and Turker (1983), also indicating that the jaw muscles are at suboptimum length at a closed jaw. The effect of jaw displacement upon sarcomere length varies between the muscle regions.…”

Section: Discussionmentioning

confidence: 86%

Heterogeneity of fiber and sarcomere length in the human masseter muscle

Eijden

Raadsheer

1992

Anat. Rec.

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This study deals with regional differences in the architectural design of the human masseter muscle. For a number of defined muscle regions the three-dimensional coordinates of origin and insertion points, and the lengths of the muscle fibers and the sarcomeres were determined in the closed jaw position. Measurements were made from cadavers and the data were used as input for a model predicting sarcomere length at other mandibular positions. At a closed jaw average muscle fiber length of the muscle regions ranged between 19.0-30.3 mm. The fibers appeared to be considerably longer (35%) anteriorly than posteriorly in the muscle, and deeply situated fibers were on average 5% shorter than superficially situated ones. Average sarcomere length of the regions ranged between 2.27-2.55 microns, indicating that at a closed jaw position sarcomeres are at suboptimum length and have different positions on the length-tension curve. In the deep layer of the muscle sarcomeres were significantly shorter (6%) than in the superficial layer. Within the superficial layer sarcomere lengths did not differ significantly, but in the deep layer sarcomeres were shorter (8%) posteriorly than anteriorly in the muscle. The model shows that jaw displacement had a different effect on sarcomere length in the muscle regions. When the jaw was rotated about a transverse axis (open/close rotation) sarcomere excursions were relatively small in the posterior muscle regions and large in the anterior regions. The reverse was true when the jaw was rotated contralaterally about a vertical axis. It is concluded that, due to heterogeneity in fiber and sarcomere lengths, the distribution of maximal isometric tension across the muscle at full effort is not uniform.

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“…This proposal has been rejected by several recent studies that have examined the relationship between maximal biting force and experimental variations in OVD. As the OVD is increased from a position of infra-gnathism (Morimoto et al, 1996) to a position 15 to 20 mm greater than the free-way space norm, the maximal biting force also increases (Boucher et al, 1959;Manns et al, 1979;Mackenna and Turker, 1983;Fields et al, 1986;Lindauer et al, 1991;Prombonas et al, 1994) (Fig. ).…”

Section: (112) Effects Of a Modification Of Head Position On The Antmentioning

confidence: 99%

“…This can be interpreted as a decrease in muscle efficiency, despite an increase in energy expenditure (Manns et al,1 979). In a clinical context, the importance of the inverse relationship between force and interocclusal distance should be noted for bat dentate (Manns et al, 1979;Mackenna and Turker, 1983; Fields et a/., 1 986; Lindauer et al, 1 991) and edentulous subjects (Prombonas et al, 1994;Morimoto et al, 1996), since the "efficiency", or the return from energy expended, is even less for edentulous patients in whom the OVD has been deliberately reduced (Morimoto et a!., 1996). In certain cases, comfort may be enhanced by increasing the OVD (Prombonas in vivo, 1994 (Hellsing, 1984).…”

Section: Regulations and Changes In The Habitual Mandibular Positionmentioning

confidence: 99%

Regulation of Mandibular Postures: Mechanisms and Clinical Implications

Woda¹,

Pionchon²,

Palla

2001

Critical Reviews in Oral Biology & Medicine

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This review argues that (1) the habitual mandibular position is constantly variable and so cannot be considered as a craniomandibular reference point, (2) there is no unique centric relation, (3) mandibular posture greatly depends on head posture, (4) clinical evaluation of the occlusal vertical dimension is mostly empirical, and (5) neither the vertical dimension at rest nor the centric relation can be determined by means of existing instrument-based clinical methods. However, some physiological conditions exist that facilitate the recording of craniomandibular position.

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Jaw separation and maximum incising force

Cited by 61 publications

References 12 publications

The effects of gape angle and bite point on bite force in bats

The effects of gape angle and bite point on bite force in bats

Heterogeneity of fiber and sarcomere length in the human masseter muscle

Regulation of Mandibular Postures: Mechanisms and Clinical Implications

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