Zygomatic Arch (zygomatic + arch)

Distribution by Scientific Domains


Selected Abstracts


A Prospective Clinical Study on Titanium Implants in the Zygomatic Arch for Prosthetic Rehabilitation of the Atrophic Edentulous Maxilla with a Follow-Up of 6 Months to 5 Years

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 3 2006
Carlos Aparicio DDS
ABSTRACT Background, Prosthetic rehabilitation with implant-supported prostheses in the atrophic edentulous maxilla often requires a bone augmentation procedure to enable implant placement and integration. However, a rigid anchorage can also be achieved by using so-called zygomatic implants placed in the zygomatic arch in combination with regular implants placed in residual bone. Purpose, The aim of the present study was to report on the clinical outcome of using zygomatic and regular implants for prosthetic rehabilitation of the severely atrophic edentulous maxilla. Materials and Methods, Sixty-nine consecutive patients with severe maxillary atrophy were, during a 5-year period, treated with a total of 69 fixed full-arch prostheses anchored on 435 implants. Of these, 131 were zygomatic implants and 304 were regular implants. Fifty-seven bridges were screw-retained and 12 were cemented. The screw-retained bridges were removed at the examination appointments and each implant was tested for mobility. In addition, the zygomatic implants were subjected to Periotest® (Siemens AG, Bensheim, Germany) measurements. The patients had at the time of this report been followed for at least 6 months up to 5 years in loading. Results, Two regular implants failed during the study period giving a cumulative survival rate of 99.0%. None of the zygomatic implants was removed. All patients received and maintained a fixed full-arch bridge during the study. Periotest measurements of zygomatic implants showed a decreased Periotest values value with time, indictating an increased stability. Three patients presented with sinusitis 14,27 months postoperatively, which could be resolved with antibiotics. Loosening of the zygomatic implant gold screws was recorded in nine patients. Fracture of one gold screw as well as the prosthesis occurred twice in one patient. Fracture of anterior prosthetic teeth was experienced in four patients. Conclusions, The results from the present study show that the use of zygomatic and regular implants represents a predictable alternative to bone grafting in the rehabilitation of the atrophic edentulous maxilla. [source]


Zygomatic complex fractures in a suburban Nigerian population

DENTAL TRAUMATOLOGY, Issue 2 2005
Vincent Ugboko
Abstract,,, A retrospective analysis of 128 zygomatic complex fractures was undertaken. There were 109 males (85.2%) and 19 females (14.8%), aged 3,74 years (mean ± SD, 33 ± 12.6 years). Patients in the third decade of life (38.3%) recorded the highest incidence. Road traffic accidents (74.2%) mainly from automobile (61.7%) and motorcycle (9.4%) involvement were the predominant etiology. While 38.8% of them presented within the first 24 h, males were relatively earlier than their female counterparts, although this was not statistically significant (P > 0.05). Class 3 fractures were the commonest (50%), followed by classes 2 (zygomatic arch) and 4, respectively. Most class 6 fractures (6.3%) resulted from gunshot injuries. There were 116 unilateral (left 63, right 53) and 12 bilateral fractures with the right side of the face recording more zygomatic arch fractures. In addition, statistical significance was observed between etiology, class and type of fracture (P < 0.05). One hundred and twenty-four (136 fractures) patients were available for treatment as four declined. Twelve cases did not require treatment while others were managed by either closed or open reduction under general anesthesia. Gillies' temporal approach was the commonest (57.1%) surgical technique employed. However the unstable nature of the fractures necessitated open reduction and transosseous wiring in 33 cases. The high prevalence of zygomatic complex fractures arising from vehicular accidents reflects the poor status of the road network in rural and suburban Nigerian communities. Hence government should improve on existing infrastructures, decongest the highways and enforce traffic laws amongst road users. In addition, the need to encourage massive investments in safer alternative transport systems is emphasized. [source]


Effects of masticatory muscle function on craniofacial morphology in growing ferrets (Mustela putorius furo)

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2003
Tailun He
Studying the effects of masticatory muscle function on craniofacial morphology in animal models with different masticatory systems is important for further understanding of related issues in humans. Forty 5-wk-old male ferrets were equally divided into two groups. One group was fed a diet of hard pellets (HDG) and the other group was fed the same diet but softened with water (SDG). Lateral and dorsoventral cephalograms were taken on each group after 6 months. Cephalometric measurements were performed by digital procedures. For SDG ferrets, the hard palate plane was more distant from the cranial base plane, and canines were more proclined compared with HDG ferrets. The SDG ferrets were also found to have smaller interfrontal and interparietal widths, and a slenderer zygomatic arch than the HDG ferrets. In the mandible, the coronoid process was generally shorter and narrower for the SDG ferrets. The effects of the altered masticatory muscle function on craniofacial morphology in growing ferrets seemed to differ from those previously reported in other animal models studied under similar experimental conditions. Such differences in the effects are presumably related to the differences in the mode of mastication, craniofacial anatomy and growth pattern in different animal models. [source]


Bizygomatic breadth determination in damaged skulls

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 5 2010
C. L. Oskam
Abstract Metric and discriminant function analyses of the skull have been used successfully to determine ancestry and sex from human skeletal remains in both forensic and archaeological contexts. However, skulls are frequently discovered in damaged condition. One structure that is commonly fragmented, even when the rest of the skull is preserved, is the zygomatic arch. The bizygomatic width is an important measurement in craniometry and in forensic facial reconstruction for determining facial width; therefore we propose a simple linear regression model to predict the bizygomatic width of skulls with damaged zygomatic arches. Thirty-one adult skulls originating from the Indian sub-continent were used to measure the bizygomatic width. Then, on the same skulls, a straight steel wire was placed at the superior surface of the temporal and zygomatic origins of the zygomatic arch to simulate the zygomatic arch reconstruction on damaged skulls. These wire measurements were used to fit a simple linear regression model between the bizygomatic widths and the wire measurements, and the estimated regression model; Bizygomatic Width (bone),=,0.61,+,1.02(wire measurement), has a very high R2 value of 0.91. Hence, this model could effectively be used to predict bizygomatic widths based on wire measurements. In addition, the bizygomatic widths and wire measurements were collected from 14 New Zealand European skulls to test the ability of the regression model to determine bizygomatic widths from different ethnic groups. This model accurately predicted the bizygomatic widths in New Zealands of European origin skulls and therefore suggests that this regression model could be used for other ethnic groups. The importance of the bizygomatic width for craniometric analysis makes this regression model particularly useful for analysing archaeological samples. Furthermore, this regression line can be used in the field of forensic facial reconstruction to reconstruct damaged zygomatic arches prior to facial reconstructions. Copyright © 2009 John Wiley & Sons, Ltd. [source]


Implant-Supported Obturator Overdenture for Extensive Maxillary Resection Patient: A Clinical Report

JOURNAL OF PROSTHODONTICS, Issue 3 2010
Cláudio Rodrigues Leles DDS
Abstract This clinical report presents an implant-retained obturator overdenture solution for a Prosthodontic Diagnostic Index Class IV maxillectomy patient with a large oronasal communication and severe facial asymmetry, loss of upper lip and midfacial support, severe impairment of mastication, deglutition, phonetics, and speech intelligibility. Due to insufficient bone support to provide satisfactory zygomaticus implant anchorage, conventional implants were placed in the body of the left zygomatic arch and in the right maxillary tuberosity. Using a modified impression technique, a cobalt-chromium alloy framework with three overdenture attachments was constructed to retain a complete maxillary obturator. Patient-reported functional and quality of life measure outcomes were dramatically improved after treatment and at the two-year follow-up. [source]


Ecomorphological analysis of the masticatory apparatus in the seed-eating bats, genus Chiroderma (Chiroptera: Phyllostomidae)

JOURNAL OF ZOOLOGY, Issue 4 2005
Marcelo R. Nogueira
Abstract Recent data have shown that owing to their seed-predator capacity Chiroderma doriae and Chiroderma villosum trophically depart from all previously studied species within the canopy fruit-bat ensemble. In this paper, the hypothesis that morphological adaptations related to granivory have evolved in these bats is investigated and discussed. A canonical variate analysis was used to search for possible divergent trends between the masticatory apparatus of Chiroderma and other stenodermatines currently recognized in the same ensemble. A total of 142 specimens representative of eight species was included in the analysis. Species of Chiroderma can be discriminated from all other species in the sample based on the increased development of masseter-related variables (height of the anterior zygomatic arch, masseter moment arm, and masseter volume), which, in conjunction with other morphological characteristics (dentition and gape angle) discussed herein, corroborates the evolution of durophagy in this group. A complementary analysis based on a Mantel test revealed that the pattern of morphological differentiation that emerged from the canonical variate analysis does not agree with the one expected based solely on the phylogenetic relationships adopted for the canopy fruit-bats studied here. This result is consistent with the hypothesis that morphological adaptations related to granivory have evolved in Chiroderma. [source]


Masticatory loading and bone adaptation in the supraorbital torus of developing macaques

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009
K. Kupczik
Abstract Research on the evolution and adaptive significance of primate craniofacial morphologies has focused on adult, fully developed individuals. Here, we investigate the possible relationship between the local stress environment arising from masticatory loadings and the emergence of the supraorbital torus in the developing face of the crab-eating macaque Macaca fascicularis. By using finite element analysis (FEA), we are able to evaluate the hypothesis that strain energy density (SED) magnitudes are high in subadult individuals with resulting bone growth in the supraorbital torus. We developed three micro-CT-based FEA models of M. fascicularis skulls ranging in dental age from deciduous to permanent dentitions and validated them against published experimental data. Applied masticatory muscle forces were estimated from physiological cross-sectional areas of macaque cadaveric specimens. The models were sequentially constrained at each working side tooth to simulate the variation of the bite point applied during masticatory function. Custom FEA software was used to solve the voxel-based models and SED and principal strains were computed. A physiological superposition SED map throughout the face was created by allocating to each element the maximum SED value from each of the load cases. SED values were found to be low in the supraorbital torus region throughout ontogeny, while they were consistently high in the zygomatic arch and infraorbital region. Thus, if the supraorbital torus arises to resist masticatory loads, it is either already adapted in each of our subadult models so that we do not observe high SED or a lower site-specific bone deposition threshold must apply. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source]


Masticatory Loading, Function, and Plasticity: A Microanatomical Analysis of Mammalian Circumorbital Soft-Tissue Structures

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 4 2010
Eldin Ja, arevi
Abstract In contrast to experimental evidence regarding the postorbital bar, postorbital septum, and browridge, there is exceedingly little evidence regarding the load-bearing nature of soft-tissue structures of the mammalian circumorbital region. This hinders our understanding of pronounced transformations during primate origins, in which euprimates evolved a postorbital bar from an ancestor with the primitive mammalian condition where only soft tissues spanned the lateral orbital margin between frontal bone and zygomatic arch. To address this significant gap, we investigated the postorbital microanatomy of rabbits subjected to long-term variation in diet-induced masticatory stresses. Rabbits exhibit a masticatory complex and feeding behaviors similar to primates, yet retain a more primitive mammalian circumorbital region. Three cohorts were obtained as weanlings and raised on different diets until adult. Following euthanasia, postorbital soft tissues were dissected away, fixed, and decalcified. These soft tissues were divided into inferior, intermediate, and superior units and then dehydrated, embedded, and sectioned. H&E staining was used to characterize overall architecture. Collagen orientation and complexity were evaluated via picrosirius-red staining. Safranin-O identified proteoglycan content with additional immunostaining performed to assess Type-II collagen expression. Surprisingly, the ligament along the lateral orbital wall was composed of elastic fibrocartilage. A more degraded organization of collagen fibers in this postorbital fibrocartilage is correlated with increased masticatory forces due to a more fracture-resistant diet. Furthermore, the lack of marked changes in the extracellular composition of the lateral orbital wall related to tissue viscoelasticity suggests it is unlikely that long-term exposure to elevated masticatory stresses underlies the development of a bony postorbital bar. Anat Rec, 293:642,650, 2010. © 2010 Wiley-Liss, Inc. [source]


The Muscles of Mastication in the Caspian Seal (Phoca caspica)

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2002
H. Endo
Summary The muscles of mastication and their related skull characters in the Caspian seal (Phoca caspica) were anatomically examined and compared with those of the Baikal (Phoca sibirica) and ringed (Phoca hispida) seals. A well-developed masseter muscle was observed in the Caspian seal, whereas the temporal muscle consisted of thin bundles. The skull of the Caspian seal possessed the same thin frontal bone and the dorso-ventrally developed zygomatic arch found in the Baikal seal that are required to install the enlarged eyeball into the orbit. The temporal bone was not robust, and the digastric muscle was well-developed in the ventral space of the auditory bulla. The present results suggest that the skull form of the Caspian seal has changed morphologically from its ringed seal-like ancestors, and suggest that the evolutionary strategy of the muscles of mastication in the Caspian seal is principally consistent with that of the Baikal seal. [source]


A Prospective Clinical Study on Titanium Implants in the Zygomatic Arch for Prosthetic Rehabilitation of the Atrophic Edentulous Maxilla with a Follow-Up of 6 Months to 5 Years

CLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 3 2006
Carlos Aparicio DDS
ABSTRACT Background, Prosthetic rehabilitation with implant-supported prostheses in the atrophic edentulous maxilla often requires a bone augmentation procedure to enable implant placement and integration. However, a rigid anchorage can also be achieved by using so-called zygomatic implants placed in the zygomatic arch in combination with regular implants placed in residual bone. Purpose, The aim of the present study was to report on the clinical outcome of using zygomatic and regular implants for prosthetic rehabilitation of the severely atrophic edentulous maxilla. Materials and Methods, Sixty-nine consecutive patients with severe maxillary atrophy were, during a 5-year period, treated with a total of 69 fixed full-arch prostheses anchored on 435 implants. Of these, 131 were zygomatic implants and 304 were regular implants. Fifty-seven bridges were screw-retained and 12 were cemented. The screw-retained bridges were removed at the examination appointments and each implant was tested for mobility. In addition, the zygomatic implants were subjected to Periotest® (Siemens AG, Bensheim, Germany) measurements. The patients had at the time of this report been followed for at least 6 months up to 5 years in loading. Results, Two regular implants failed during the study period giving a cumulative survival rate of 99.0%. None of the zygomatic implants was removed. All patients received and maintained a fixed full-arch bridge during the study. Periotest measurements of zygomatic implants showed a decreased Periotest values value with time, indictating an increased stability. Three patients presented with sinusitis 14,27 months postoperatively, which could be resolved with antibiotics. Loosening of the zygomatic implant gold screws was recorded in nine patients. Fracture of one gold screw as well as the prosthesis occurred twice in one patient. Fracture of anterior prosthetic teeth was experienced in four patients. Conclusions, The results from the present study show that the use of zygomatic and regular implants represents a predictable alternative to bone grafting in the rehabilitation of the atrophic edentulous maxilla. [source]


Bizygomatic breadth determination in damaged skulls

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 5 2010
C. L. Oskam
Abstract Metric and discriminant function analyses of the skull have been used successfully to determine ancestry and sex from human skeletal remains in both forensic and archaeological contexts. However, skulls are frequently discovered in damaged condition. One structure that is commonly fragmented, even when the rest of the skull is preserved, is the zygomatic arch. The bizygomatic width is an important measurement in craniometry and in forensic facial reconstruction for determining facial width; therefore we propose a simple linear regression model to predict the bizygomatic width of skulls with damaged zygomatic arches. Thirty-one adult skulls originating from the Indian sub-continent were used to measure the bizygomatic width. Then, on the same skulls, a straight steel wire was placed at the superior surface of the temporal and zygomatic origins of the zygomatic arch to simulate the zygomatic arch reconstruction on damaged skulls. These wire measurements were used to fit a simple linear regression model between the bizygomatic widths and the wire measurements, and the estimated regression model; Bizygomatic Width (bone),=,0.61,+,1.02(wire measurement), has a very high R2 value of 0.91. Hence, this model could effectively be used to predict bizygomatic widths based on wire measurements. In addition, the bizygomatic widths and wire measurements were collected from 14 New Zealand European skulls to test the ability of the regression model to determine bizygomatic widths from different ethnic groups. This model accurately predicted the bizygomatic widths in New Zealands of European origin skulls and therefore suggests that this regression model could be used for other ethnic groups. The importance of the bizygomatic width for craniometric analysis makes this regression model particularly useful for analysing archaeological samples. Furthermore, this regression line can be used in the field of forensic facial reconstruction to reconstruct damaged zygomatic arches prior to facial reconstructions. Copyright © 2009 John Wiley & Sons, Ltd. [source]