Paul Dechow | Texas A&M Health Science Center (original) (raw)

Papers by Paul Dechow

Journal of Biomechanics, 1983

A bite force transducer consisting of two differential strain beams with four strain gages in a f... more A bite force transducer consisting of two differential strain beams with four strain gages in a full bridge configuration was modified for measuring occlusal forces in rhesus monkeys. A procedure of muscle stimulation (2(t50 V, 60 Hz, and 0.8 ms duration) produced maximal unilateral masticatory muscle contraction when stimulating electrodes were placed in the masseter muscle. Tests of this procedure revealed reproducible results and a potential for use in studies of the force of isometric contraction of the masticatory muscles in normal and experimentally altered macaques and other primates.

The FASEB Journal, Apr 1, 2013

Assessing the variation of the internal bone structure, anisotropy and orientation in the browrid... more Assessing the variation of the internal bone structure, anisotropy and orientation in the browridge across regions and species can aid in our understanding of craniofacial adaptation. Also, quantifying species and region specific variation may serve to improve the accuracy of finite element models. In this study, μCT was used to determine the structural properties, degree of anisotropy (DA) and primary trabecular orientation in 3 equally divided browridge regions of 8 Homo, 5 Pan, 7 Cebus, 4 Papio, and 1 Gorilla. Both bone volume fraction (BVF) and degree of anisotropy (DA) differed significantly by species (Kruskal‐Wallis Test, p<0.001 and p<0.015, respectively). Most regions across species showed orthotropy. In all species and regions, trabeculae tend to show less variability in orientation across transverse and coronal planes. Orientations in the sagittal plane instead show higher variability across individuals. The results suggest that BVF, DA and orientation of trabecular‐like bone within the supraorbital region may be reflective of feeding strategies and that characterization of subcortical structure in craniofacial regions may improve finite element models. Additional study of trabecular bone orientation within zygomatic regions is ongoing to examine how trabecular bone orientation and DA differ across the entire craniofacial region in these species.Grant Funding Source: Science Foundation Physical Anthropology HOMINID program (NSF BCS 0725141)

American Journal of Orthodontics and Dentofacial Orthopedics, Jul 1, 2012

International Journal of Oral & Maxillofacial Implants, 2014

This assignment applies to all translations of the Work as well as to preliminary display/posting... more This assignment applies to all translations of the Work as well as to preliminary display/posting of the abstract of the accepted article in electronic form before publication. If any changes in authorship (order, deletions, or additions) occur after the manuscript is submitted, agreement by all authors for such changes must be on file with the Publisher. An author's name may be removed only at his/her written request. (Note: Material prepared by employees of the US government in the course of their official duties cannot be copyrighted.

Zoology, Oct 1, 2017

Highlights  The elastic properties of rhesus macaque mandibular cortical bone are characterized.... more Highlights  The elastic properties of rhesus macaque mandibular cortical bone are characterized.  They are compared to the elastic properties from mandibles of dentate humans and baboons.  There are regional variations in the elastic properties of macaque mandibular cortical bone.  There are both similarities and differences with those of humans and baboons.  The biological and structural basis of these differences is poorly understood despite their biomechanical relevance.

Archives of Oral Biology, Oct 1, 1994

Although there have been a number of experimental studies of temporomandibular joint loading, the... more Although there have been a number of experimental studies of temporomandibular joint loading, the precise relation between condylar load and condylar strain is incompletely understood. This in vitro study determined the magnitudes and directions of the principal components of strain on the four surfaces of the condylar process of human cadaver mandibles during loading with selected simulated muscle forces, with simultaneous measurement of occlusal and joint forces. Rosette strain gauges were placed on each of the four surfaces and the mandibles were loaded by a load cell to simulate the action of the masseter and medial pterygoid muscles. Force and strain values were measured at five different bite positions and nine different positions of the resultant muscle force. Forces and strain values were highest when the resultant muscle force was closest to the joint and the bite position was furthest from the joint. The ratios of bite force to joint force and the ratios of forces between the two joints conformed to theoretical predictions of many previous models, with the balancing-side joint being loaded more heavily than the working-side joint. At all gauge positions the maximum principal strain was tensile, the minimum principal strain was compressive, and the absolute strain values were correlated with the magnitude of the force on the condyle. However, under the chosen loading regimen, the ratio of compressive to tensile strain differed among the four surfaces. The highest levels of tensile strain occurred on the anterior and lateral surfaces and the highest compressive strain occurred on the posterior surface. It was not possible to detect significant changes in strain patterns due to bite position or muscle force position, that were independent of the force magnitudes.

Journal of Human Evolution, Oct 1, 2006

American Journal of Physical Anthropology, 2006

Bones of the face and cranial vault meet at sutural boundaries. These sutures are of great import... more Bones of the face and cranial vault meet at sutural boundaries. These sutures are of great importance for craniofacial growth. Although the effects that the sutures have on modulating craniofacial strains have been investigated, how sutural fusion influences primate craniofacial biomechanics and adaptation are less considered. Confounding this problem is the lack of any systematic data on patterns of craniofacial sutural fusion from animals of known age and sex. This study examined the status of 28 sutures in Macaca mulatta skulls from a collection of animals of known age and sex from Cayo Santiago, Puerto Rico. Survival analysis showed that most animals died before all sutures fused. There was high variation in the age at which individual sutures or sutural sections were fused in M. mulatta,

Archives of Oral Biology, 1996

The anatomical record, Oct 1, 2006

Five of the bones that characteristically comprise the cranial vault articulate on the lateral as... more Five of the bones that characteristically comprise the cranial vault articulate on the lateral aspect of the skull at or near the cephalometric landmark referred to as the pterion. The pattern of articulation in the sutures associated with these bones varies among and within primate species and has been used as a criterion for classification in taxonomic studies, as well as in archeological and forensic studies. Within species, the sutural patterns found within the region of the pterion have remarkable consistency, which lead to the hypothesis that these patterns have a genetic basis. Sutural pattern variations were investigated at the pterion in 422 skulls from 66 rhesus monkey families with known genealogies from the long-standing colony on Cayo Santiago. Four specific types of articulation patterns were recorded. The results demonstrated that the most common suture pattern at the pterion of Cayo Santiago rhesus monkeys (86%; similar to that seen in some other anthropoid species but not humans and some apes) was characterized by an articulation between the temporal bone and parietal bone. Articulation between the sphenoid and parietal bones (type SP) accounted for 14% of the specimens and was concentrated in a dozen families. Mothers with the SP phenotype had a high incidence of offspring with SP phenotypes. Most non-SP mothers having SP offspring had siblings or family members from previous generations with the SP type. This is the first study to examine variation in sutural patterns at the pterion in pedigrees. Variation of sutural patterns shows familial aggregation, suggesting that this variation is heritable. Future work will be focused on defining the inheritance patterns of variation at the pterion, with the ultimate objective of identifying the specific genes involved and their mechanism of action.

American Journal of Physical Anthropology, Oct 1, 1990

The 84th Annual Meeting of the American Association of Physical Anthropologists, St. Louis, MO, 2015

The 86th Annual Meeting of the American Association of Physical Anthropologists, New Orleans, 2017

The FASEB Journal, Apr 1, 2015

The FASEB Journal, Mar 1, 2006

Five bones of the cranial vault articulate on the lateral aspect of the skull near the pterion. T... more Five bones of the cranial vault articulate on the lateral aspect of the skull near the pterion. The pattern of articulation in these sutures varies among and within primate species and has been use...

PubMed, Oct 12, 2012

Purpose: This study tested the effects of phosphate treatment of titanium on bone volume fraction... more Purpose: This study tested the effects of phosphate treatment of titanium on bone volume fraction (BV/TV) at 30 to 60 Μm from the implant surface using microcomputed tomography to analyze the mineralized tissue. Materials and methods: Electrolytically phosphated (50/100 volts [T1/T2]) or nonphosphated 3.3- X 8-mm titanium implants (C) with sandblasted acid-etched surfaces were placed in 40 mandibular sites in five foxhounds 6 weeks after the extraction of the premolars. After 4 weeks, the animals were sacrificed, and BV/TV was analyzed using microcomputed tomography. Results: The mean BV/TV (± standard deviation) of the control implants was 31.4% ± 15.3% (range, 10.9% to 55.3%). For the T1 implants, a mean BV/TV of 38.4% ± 10.7% (range, 21.6% to 57.3%) was seen, and for T2 implants, the mean BV/TV was 40.3% ± 15.1% (range, 16.5% to 61.1%). Mean BV/TV values for the groups were not significantly different. For all groups (C, T1, and T2), there were no significant differences in BV/TV at the most coronal slices. For all groups, there was a positive slope showing more bone apposition as the slices moved from coronal to apical. The T2 group showed significantly increased mineralized tissue moving from the coronal to the apical section of the implant, compared to the control and T1 implants. Conclusion: Access to better blood supply and bone cells from the marrow spaces in the apical regions may lead to a better trabecular bone response. Increased mineralized tissue apposition may allow for accelerated loading and more predictable implant placement in sites with poor quality bone or patients with compromised bone healing.

International Journal of Oral & Maxillofacial Implants, 2013

American Journal of Orthodontics and Dentofacial Orthopedics, Jul 1, 2017

The FASEB Journal

The zygomatic region and lateral orbital wall are important structural components of the primate ... more The zygomatic region and lateral orbital wall are important structural components of the primate craniofacial skeleton, providing attachment for muscles, housing and protecting the eye, and resisti...