Craniofacial morphology: A principal component analysis

Cleall, John F.; BeGole, Ellen A.; Chebib, F. S.

doi:10.1016/0002-9416(79)90097-6

Cited by 27 publications

(16 citation statements)

References 3 publications

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“…Our work confirms the existence of a correlation between the cranial base angle, prognathism, and palatal plane angle (Bjork, 1955) and the lack of correlation of this variable with facial width (Anderson and Popovich, 1983). Our results are also similar to those of Cleall et al (1979) and Brown et al (19651, both based on material consisting of lateral cephalometric X-ray films. It is concluded that our analysis of limited material has produced a description of cranial variation that confirms the ones generated by studies using larger sample sizes and different procedures.…”

Section: Muscular Variablessupporting

confidence: 94%

Correlations between the cross‐sectional area of the jaw muscles and craniofacial size and shape

Weijs¹,

Hillen

1986

American J Phys Anthropol

190

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In adult human subjects, the correlations were determined between the cross-sectional areas of the jaw muscles (measured in CT scans) and a number of facial angles and dimensions (measured from lateral radiographs). Multivariate statistical analysis of the skeletal variables in a group of 50 subjects led to the recognition of six independent factors determining facial shape, i.e., cranial base length, lower facial height, cranial base flexure and prognathism, facial width, mandibular length, and upper facial height. In 29 of these subjects, the cross-sectional areas of the jaw muscles were determined, and correlations between these areas and the scores on the above-mentioned factors were calculated. It appeared that the cross-sectional areas of temporalis and masseter muscles correlated positively with facial width, whereas the areas of masseter and both pterygoid muscles did so with mandibular length. It has been shown experimentally that a decrease in jaw muscle size in various animals likewise has an effect on facial width and mandibular length. Our results therefore support the hypothesis that in man too the jaw muscles affect facial growth and partly determine the final facial dimensions. They also hint that the role of each muscle is different.

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Section: Muscular Variablessupporting

confidence: 94%

Correlations between the cross‐sectional area of the jaw muscles and craniofacial size and shape

Weijs¹,

Hillen

1986

American J Phys Anthropol

190

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“…Recent observations from mathematical models simulating jaw biomechanics indicate that muscle cross-sectional sizes and patterns of activation, as well as the moment arms ofmuscles, bite points, and mandibular condyles, are the major determinants of bite and articular forces (Nelson and Hannam, 1982, 1983Osborn and Baragar, 1985;Smith et al, 1986;Hatcheret al, 1986;Throckmorton and Throckmorton, 1985;Throckmorton, 1985;Nelson, 1986;Iwasaki, 1987;Baragar and Osborn, 1987;Faulkner et al, 1987;Koolstra et al, 1988). Since modern human populations show considerable diversity in craniofacial form (Solow, 1966;Brown et al, 1965;Bjork, 1963;Cleall et al, 1979;Anderson and Popovitch, 19831, corresponding variations in some or all of these determinants of tooth and articular forces are likely. It also seems theoretically possible for subjects with apparently different craniofacial morphologies to function with equal biomechanical efficiency provided the correct combinations of determinant variables exist.…”

mentioning

confidence: 97%

Relationships between the size and spatial morphology of human masseter and medial pterygoid muscles, the craniofacial skeleton, and jaw biomechanics

Hannam

Wood

1989

American J Phys Anthropol

179

111

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The relationship between human craniofacial morphology and the biomechanical efficiency of bite force generation in widely varying muscular and skeletal types is unknown. To address this problem, we selected 22 subjects with different facial morphologies and used magnetic resonance imaging, cephalometric radiography, and data from dental casts to reconstruct their craniofacial tissues in three dimensions. Conventional cephalometric analyses were carried out, and the cross-sectional sizes of the masseter and medial pterygoid muscles were measured from reconstituted sections. The potential abilities of the muscles to generate bite forces at the molar teeth and mandibular condyles were calculated according to static equilibrium theory using muscle, first molar, and condylar moment arms. On average, the masseter muscle was about 66% larger in cross section than the medial pterygoid and was inclined more anteriorly relative to the functional occlusal plane. There was a significant positive correlation (P less than 0.01) between the cross-sectional areas of the masseter and medial pterygoid muscles (r = 0.75) and between the bizygomatic arch width and masseter cross-sectional area (r = 0.56) and medial pterygoid cross-sectional area (r = 0.69). The masseter muscle was always a more efficient producer of vertically oriented bite force than the medial pterygoid. Putative bite force from the medial pterygoid muscle alone correlated positively with mandibular length and inversely with upper face height. When muscle and tooth moment arms were considered together, a system efficient at producing force on the first molar was statistically associated with a face having a large intergonial width, small intercondylar width, narrow dental arch, forward maxilla, and forward mandible. There was no significant correlation between muscle cross-sectional areas and their respective putative bite forces. This suggests that there is no simple relationship between the tension-generating capacity of the muscles and their mechanical efficiency as described by their spatial arrangement. The study shows that in a modern human population so many combinations of biomechanically relevant variables are possible that subjects cannot easily be placed into ideal or nonideal categories for producing molar force. Our findings also confirm the impression that similar bite-force efficiencies can be found in subjects with disparate facial features.

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“…Von Cleall et al [7] wurden an FRS-Bildern sechs PCs identifiziert, die 68% der Varianz erklären. Komponente 1 bildete zu einem großen Teil vertikale Aspekte ab, Komponente 2 mehr anterior-posteriore Verhältnisse (∠ SNB).…”

Section: Landmarksunclassified

“…Cleall et al [7] identified in lateral cephalograms six PCs which were responsible for 68% of the variance: Component 1 mostly indicated vertical aspects, and component 2 the anterior-posterior relationships (∠ SNB). Another successful study using PCA and centroid size on 3D surface scans was applied in examining facial growth [17].…”

Section: Introductionmentioning

confidence: 99%