Vertical Midface Lifting: An Improved Technique for Asians.

BACKGROUND: Treatment of the aging midface is increasingly deemed a key part of facial and periorbital rejuvenation. Compared with Westerners, Asians tend to have a relatively prominent zygoma and mandibular angle, thicker dermis, and greater propensity for scar formation. OBJECTIVE: This study was performed to review our surgical method of vertical midface lifting in Asian patients and evaluate the clinical outcomes. METHODS AND MATERIALS: This retrospective observational study involved 116 Asian women who complained of an aged midface. All patients underwent midface rejuvenation surgery with one lower eyelid incision and 2 small frontal-temporal incisions. Clinical results were assessed objectively using photographs and subjectively by a patient satisfaction survey. RESULTS: All patients recovered well without major complications. High patient satisfaction (94%) was attained. The improvement scores as evaluated by the panel demonstrated a higher level of improvement for the malar eminence (8.3 ± 0.6), nasojugal groove (8.0 ± 0.8), and nasolabial fold (7.9 ± 0.7) than for the lower face (6.2 ± 1.0). CONCLUSION: Our vertical midface lift technique is safe and effective for older Asian patients with a midface aging appearance. LEVEL OF EVIDENCE: Therapeutic IV.

Comparison of bone thickness in infrazygomatic crest area at various miniscrew insertion angles in Dravidian population - A cone beam computed tomography study.

INTRODUCTION: Infrazygomatic crest miniscrews are an important advancement in the field of orthodontics for anchorage reinforcement. The size of the miniscrews and the site of placement depend on the bone thickness in the infazygomatic crest area. The bone morphology and the thickness vary among different ethnicities of population. OBJECTIVES: To assess the bone thickness in the infrazygomatic crest area around the distobuccal root of the maxillary first molar using cone beam computed tomography and determine the best possible site and angulation for the placement of the miniscrew. Therefore, to determine the size of the implant that will suit the Dravidian population. METHODS: The infrazygomatic crest bone thickness was evaluated on 10 patients using cone beam computed tomography. The measurements were made along the distobuccal root of maxillary first molar at different angulations ranging from 75° to 40° to the occlusal surface of the molar. RESULTS: The infrazygomatic crest bone thickness was of 4.5mm to 9mm for the Dravidian population, when measured at an angle of 40° to 75° to the maxillary first molar occlusal plane and of 11 to 17mm above the occlusal plane. Student t-test (confidence interval 95%) was done to determine gender variation and compare the bone thickness of right and left side. ANOVA and post-hoc test were done to find the statistical difference between the bone thickness measured at different insertion angles. CONCLUSIONS: The best possible site for miniscrew insertion is 12 to 17mm above the occlusal plane at an angle of 65° to 70°, with no injury to the adjacent anatomical structures, no mucosal irritation and adequate stability for the miniscrew. The ideal infrazygomatic crest screw length for Dravidian population is 9 to 11mm.

The difference of stress distribution of maxillary expansion using rapid maxillary expander (RME) and maxillary skeletal expander (MSE)-a finite element analysis.

BACKGROUND: Maxillary skeletal expander (MSE) in combination with miniscrews was developed to overcome the drawbacks that may have resulted from the application of conventional rapid maxillary expander (RME). This research was conducted to analyze the difference of stress distribution of maxillary expansion using RME and MSE in the region of interests (ROIs): first molars (M1), palatal alveolar bones of M1, palatine sutures, zygomatic sutures, miniscrews, and their surrounding bones. METHODS: A dry skull was scanned using CBCT and rendered into a three-dimensional (3D) model of craniomaxillary structures. The data analysis was done both visually and numerically. RESULT: The stress distributions in RME group were located at the palatal side of M1, mesial side of palatal alveolar of M1, pulp chamber of M1, and inferior cortex of palatine sutures. The stress distributions in the MSE group were located at the distopalatal cusp of M1, palatal side of palatal alveolar of M1, and inferior and superior cortex of palatine sutures. The stress distributions in zygomatic sutures on both groups were located at the zygomaticotemporal sutures, whereas in the miniscrews, the stress were located at the anterior miniscrews and palatal side of surrounding bones. CONCLUSIONS: There were significant differences of stress distribution of maxillary expansion measured in the ROIs in the craniomaxillary 3D model using RME and MSE.

Zygomaticomaxillary modifications in the horizontal plane induced by micro-implant-supported skeletal expander, analyzed with CBCT images.

BACKGROUND: Miniscrew-assisted rapid palatal expansion (MARPE) has been adopted in recent years to expand the maxilla in late adolescence and adult patients. Maxillary Skeletal Expander (MSE) is a device that exploits the principles of skeletal anchorage to transmit the expansion force directly to the maxillary bony structures and is characterized by the miniscrews' engagement of the palatal and nasal cortical bone layers. In the literature, it has been reported that the zygomatic buttress is a major constraint that hampers the lateral movement of maxilla, since maxilla is located medially to the zygomatic arches. The objective of the present study is to analyze the changes in the zygomatic bone, maxillary bone, and zygomatic arches and to localize the center of rotation for the zygomaticomaxillary complex in the horizontal plane after treatment with MSE, using high-resolution cone-beam computed tomography (CBCT) images. METHODS: Fifteen subjects with a mean age of 17.2 (± 4.2) years were treated with MSE. CBCT records were taken before and after miniscrew-assisted maxillary expansion; three linear and four angular parameters were identified in the axial zygomatic section (AZS) and were compared from pre-treatment to post-treatment using the Wilcoxon signed rank test. RESULTS: Anterior inter-maxillary distance increased by 2.8 mm, posterior inter-zygomatic distance by 2.4 mm, angle of the zygomatic process of the temporal bone by 1.7° and 2.1° (right and left side) (P < 0.01). Changes in posterior inter-temporal distance and zygomaticotemporal angle were negligible (P > 0.05). CONCLUSIONS: In the horizontal plane, the maxillary and zygomatic bones and the whole zygomatic arch were significantly displaced in a lateral direction after treatment with MSE. The center of rotation for the zygomaticomaxillary complex was located near the proximal portion of the zygomatic process of the temporal bone, more posteriorly and more laterally than what has been reported in the literature for tooth-borne expanders. Bone bending takes place in the zygomatic process of the temporal bone during miniscrew-supported maxillary expansion.

Structural biomechanics of the craniomaxillofacial skeleton under maximal masticatory loading: Inferences and critical analysis based on a validated computational model.

BACKGROUND: The trend towards optimizing stabilization of the craniomaxillofacial skeleton (CMFS) with the minimum amount of fixation required to achieve union, and away from maximizing rigidity, requires a quantitative understanding of craniomaxillofacial biomechanics. This study uses computational modeling to quantify the structural biomechanics of the CMFS under maximal physiologic masticatory loading. METHODS: Using an experimentally validated subject-specific finite element (FE) model of the CMFS, the patterns of stress and strain distribution as a result of physiological masticatory loading were calculated. The trajectories of the stresses were plotted to delineate compressive and tensile regimes over the entire CMFS volume. RESULTS: The lateral maxilla was found to be the primary vertical buttress under maximal bite force loading, with much smaller involvement of the naso-maxillary buttress. There was no evidence that the pterygo-maxillary region is a buttressing structure, counter to classical buttress theory. The stresses at the zygomatic sutures suggest that two-point fixation of zygomatic complex fractures may be sufficient for fixation under bite force loading. CONCLUSIONS: The current experimentally validated biomechanical FE model of the CMFS is a practical tool for in silico optimization of current practice techniques and may be used as a foundation for the development of design criteria for future technologies for the treatment of CMFS injury and disease.

The Biomechanics of Bony Facial "Buttresses" in South African Australopiths: An Experimental Study Using Finite Element Analysis.

Australopiths exhibit a number of derived facial features that are thought to strengthen the face against high and/or repetitive loads associated with a diet that included mechanically challenging foods. Here, we use finite element analysis (FEA) to test hypotheses related to the purported strengthening role of the zygomatic root and "anterior pillar" in australopiths. We modified our previously constructed models of Sts 5 (Australopithecus africanus) and MH1 (A. sediba) to differ in the morphology of the zygomatic root, including changes to both the shape and positioning of the zygomatic root complex, in addition to creating variants of Sts 5 lacking anterior pillars. We found that both an expanded zygomatic root and the presence of "anterior pillars" reinforce the face against feeding loads. We also found that strain orientations are most compatible with the hypothesis that the pillar evolved to resist loads associated with premolar loading, and that this morphology has an ancillary effect of strengthening the face during all loading regimes. These results provide support for the functional hypotheses. However, we found that an anteriorly positioned zygomatic root increases strain magnitudes even in models with an inflated/reinforced root complex. These results suggest that an anteriorly placed zygomatic root complex evolved to enhance the efficiency of bite force production while facial reinforcement features, such as the anterior pillar and the expanded zygomatic root, may have been selected for in part to compensate for the weakening effect of this facial configuration. Anat Rec, 300:171-195, 2017. © 2016 Wiley Periodicals, Inc.

Opposing Extremes of Zygomatic Bone Morphology: Australopithecus Boisei versus Homo Neanderthalensis.

The lateral margin of the zygomatic bone of Australopithecus boisei flares both anteriorly and laterally. As a result, the bone loses the suspensory bracing of the facial frame and is transformed into a visor-like structure that supports itself and gains its rigidity from its shape. The coronally oriented bony plates and the outline of the facial mask help the A. boisei face resist the effect of the visor-like structure, which tends to pull the bone plates of the face away from the midline. On the other hand, the nearly sagittal orientation of the zygomatic bone in Homo neanderthalensis helps the face resist torque and bending forces, which themselves stem from the positioning of the bite point on the anterior teeth. Although the zygomatic bones of these two taxa are highly specialized, they differ fundamentally from each other. Anat Rec, 300:152-159, 2017. © 2016 Wiley Periodicals, Inc.

Zygomatic Root Position in Recent and Fossil Hominids.

The relative position of the zygomatic root to the dentition plays a crucial role in determining the overall strength of the face in response to bite forces. The powerful superficial head of the masseter arises there and the zygomaticoalveolar crest (ZAC) is discussed as a buttressing feature of the face. For instance, a more forwardly or backwardly positioned zygomatic root or a lower or higher vertical distance to the dentition could be indicative for evolutionary adaptations to particular loading regimes which are associated with diet. We therefore examined the morphology of the maxilla using state-of-the-art 3D Geometric Morphometric methods. The data set was reduced to a minimum of relevant measurements and includes five landmarks (pr, ol, zm, lingual and buccal midpoint of second molar alveoli) and three curves with semilandmarks along the lingual and buccal alveolar rim and the ZAC. Results show a stunning overlap in shape variation. We find no clear pattern of shape that would allow separating different hominid groups with confidence, except two extreme forms-Paranthropines and Neanderthals. We also find no clear trend over time. Australopithecines, Habilines, Erectines, and Middle Pleistocene Homo can be very similar to modern humans. Even great apes are within or not far from the central shape distribution of Homo, but they separate clearly from gracile and robust Australopithecines. We discuss the shape factors underlying our data. The geometry studied allows simple measurements and analyses and is thus potentially interesting for classification purposes of extreme forms. Anat Rec, 300:160-170, 2017. © 2016 Wiley Periodicals, Inc.

Zygomaticomaxillary Morphology and Maxillary Sinus Form and Function: How Spatial Constraints Influence Pneumatization Patterns among Modern Humans.

Previous research has suggested that the maxillary sinuses may act as "zones of accommodation" for the nasal region, minimizing the impact of climatic-related changes in nasal cavity breadth on surrounding skeletal structures. However, a recent study among modern human crania has identified that, in addition to nasal cavity breadth, sinus morphology also tracks lateral facial form, especially anterior-posterior positioning of the zygomatics. Here, we expand upon this previous study to further investigate these covariation patterns by employing three samples with distinct combinations of nasal and zygomatic morphologies: Northern Asians (n = 28); sub-Saharan Africans (n = 30); and Europeans (n = 29). For each cranium, 30 landmarks were digitized from CT-rendered models and subsequently assigned to either a midfacial or maxillary sinus "block." Two block partial least squares (2B-PLS) analyses indicate that sinus morphology primarily reflects superior-inferior dimensions of the midface, rather than either nasal cavity breadth or zygomatic position. Specifically, individuals with relatively tall midfacial skeletons exhibit more inferiorly and laterally expanded sinuses compared to those with shorter midfaces. Further, separate across-group and within-group 2B-PLS analyses indicate that regional differences between samples primarily build upon a common pattern of midfacial and sinus covariation already present within each regional group. Allometry, while present, only explains a small portion of the midface-sinus covariation pattern. We conclude that previous findings of larger maxillary sinuses among cold-adapted individuals are not predominantly due to possession of relatively narrow nasal cavities, but to greater maxillary and zygomatic heights. Implications for sinus function and midfacial ontogeny are discussed. Anat Rec, 300:209-225, 2017. © 2016 Wiley Periodicals, Inc.

Zygomatic Arch Cortical Area and Diet in Haplorhines.

The influence that various types of ingested foods have on the form (size and shape) of specific features of the masticatory system is an area in which many questions remain unanswered. The bony zygomatic arch, the focus of this study, is directly linked to the masticatory system because it serves as the anchor for the masseter muscle, a primary muscle of chewing and source of masticatory force. However, the influence of diet and the forces associated with different diet types on the arch's internal bone architecture is not well understood. Despite the breadth of work centered around the craniofacial complex and biomechanics of mastication, there is a need for further investigations into the functional relationships between specific bony features that experience high strains, (e.g., the zygomatic arch), and the masticatory forces generated by different diets (e.g., mechanically resistant versus non- mechanically resistant) across non-human primates. A hypothesis and series of predictions assessing diet in relation to variability in cortical area distributions and values of section moduli (measures of bone strength) throughout the zygomatic arch were tested in a sample of haplorhine primates. Cortical area and measures of section moduli appear to track with the known masticatory strain distribution along the zygomatic arch. Pairwise comparisons between closely related taxa of different diets reveal significant differences in anterior cortical area and section moduli values. These results imply that differences in masticatory loading due to diet manifest in the zygomatic arch's internal bone structure. Anat Rec, 299:1789-1800, 2016. © 2016 Wiley Periodicals, Inc.

Development, Structure, and Function of the Zygomatic Bones: What is New and Why Do We Care?

This issue of The Anatomical Record is the first of a two-volume set on the zygoma (also called the cheek bone, the zygomatic bone, the malar, or the jugal, the latter term being used in vertebrates other than mammals). The zygoma is an important component of the craniofacial skeleton, in which the zygoma is a connection between the midfacial and the cranial skeletons; has a functional role as the origin of one of the masticatory muscles, the masseter muscle, and several facial muscles; has been considered as an essential buttress of the facial skeleton for resisting masticatory forces; and has importance for determining phylogenetic relationships. In humans, the zygoma is also of aesthetic significance for facial appearance, and its restoration following trauma has resulted in a large clinical literature. In this first volume of this Special Issue, a wide ranging series of papers discuss studies related to issues of development, structure, and function of the zygoma and closely related parts of the craniofacial skeleton in mammals, and in particular primates. This Introductory article provides an overview in which we discuss the primary findings of these studies and some of their implications. The second volume, which will be published as the January 2017 issue of The Anatomical Record, will focus on variation and evolution of the zygoma throughout the vertebrates. Anat Rec, 299:1611-1615, 2016. © 2016 Wiley Periodicals, Inc.

The Biomechanics of Zygomatic Arch Shape.

Mammalian zygomatic arch shape is remarkably variable, ranging from nearly cylindrical to blade-like in cross section. Based on geometry, the arch can be hypothesized to be a sub-structural beam whose ability to resist deformation is related to cross sectional shape. We expect zygomatic arches with different cross sectional shapes to vary in the degree to which they resist local bending and torsion due to the contraction of the masseter muscle. A stiffer arch may lead to an increase in the relative proportion of applied muscle load being transmitted through the arch to other cranial regions, resulting in elevated cranial stress (and thus, strain). Here, we examine the mechanics of the zygomatic arch using a series of finite element modeling experiments in which the cross section of the arch of Pan troglodytes has been modified to conform to idealized shapes (cylindrical, elliptical, blade-like). We find that the shape of the zygomatic arch has local effects on stain that do not conform to beam theory. One exception is that possessing a blade-like arch leads to elevated strains at the postorbital zygomatic junction and just below the orbits. Furthermore, although modeling the arch as solid cortical bone did not have the effect of elevating strains in other parts of the face, as had been expected, it does have a small effect on stress associated with masseter contraction. These results are counterintuitive. Even though the arch has simple beam-like geometry, we fail to find a simple mechanical explanation for the diversity of arch shape. Anat Rec, 299:1734-1752, 2016. © 2016 Wiley Periodicals, Inc.

Betwixt and Between: Intracranial Perspective on Zygomatic Arch Plasticity and Function in Mammals.

The zygomatic arch is morphologically complex, providing a key interface between the viscerocranium and neurocranium. It also serves as an attachment site for masticatory muscles, thereby linking it to the feeding apparatus. Though morphological variation related to differential loading is well known for many craniomandibular elements, the adaptive osteogenic response of the zygomatic arch remains to be investigated. Here, experimental data are presented that address the naturalistic influence of masticatory loading on the postweaning development of the zygoma and other cranial elements. Given the similarity of bone-strain levels among the zygoma and maxillomandibular elements, a rabbit and pig model were used to test the hypothesis that variation in cortical bone formation and biomineralization along the zygomatic arch and masticatory structures are linked to increased stresses. It was also hypothesized that neurocranial structures would be minimally affected by varying loads. Rabbits and pigs were raised for 48 weeks and 8 weeks, respectively. In both experimental models, CT analyses indicated that elevated masticatory loading did not induce differences in cortical bone thickness of the zygomatic arch, though biomineralization was positively affected. Hypotheses were supported regarding bone formation for maxillomandibular and neurocranial elements. Varying osteogenic responses in the arch suggests that skeletal adaptation, and corresponding variation in performance, may reside differentially at one level of bony architecture. Thus, it is possible that phenotypic diversity in the mammalian zygoma is due more singularly to natural selection (vs. plasticity). These findings underscore the complexity of the zygomatic arch and, more generally, determinants of skull form. Anat Rec, 299:1646-1660, 2016. © 2016 Wiley Periodicals, Inc.

Divided Zygomatic Bone in Primates With Implications of Skull Morphology and Biomechanics.

Typically the zygoma is a single bone in the facial skeleton whose shape uniquely copes with loads associated with mastication. Rarely but naturally, the zygoma is divided into two or more parts by supernumerary sutures. These extra intrazygomatic sutures are located at an area of critical morphological and biomechanical importance, yet their impacts have not been studied. In this study, the morphological and possible biomechanical consequences of the divided zygoma (DZ) were investigated in primates including rhesus macaques (Macaca mulatta), orangutans (Pongo abelii and P. pygmaeus), and modern humans (Homo sapiens). Results demonstrated that a unilateral supernumerary suture within the zygoma affected facial symmetry. The superior division of the divided zygoma was normally slender along with the adjacent frontal bone parts; while the inferior division of the divided zygoma was normally more robust, along with stronger temporal and maxillary bones. These were possible biomechanical consequences, in which the stresses incurred during normal masticatory activities were shunted from the upper face to the lower face, especially along the zygomatic arch. These findings revealed that the DZ condition would alter overall morphology of the midface of the affected side, and unfavorably affect the pattern of stress distribution in the loaded side of the face during mastication. The developmental mechanisms for the supernumerary sutures dividing the zygoma were unclear. Further insights into this rare condition may deepen our understanding of craniofacial form, adaptation, developmental plasticity, and evolution, and help to improve therapeutic philosophies in corrective and regenerative medicine. Anat Rec, 299:1801-1829, 2016. © 2016 Wiley Periodicals, Inc.

Elastic Properties of Chimpanzee Craniofacial Cortical Bone.

Relatively few assessments of cranial biomechanics formally take into account variation in the material properties of cranial cortical bone. Our aim was to characterize the elastic properties of chimpanzee craniofacial cortical bone and compare these to the elastic properties of dentate human craniofacial cortical bone. From seven cranial regions, 27 cylindrical samples were harvested from each of five chimpanzee crania. Assuming orthotropy, axes of maximum stiffness in the plane of the cortical plate were derived using modified equations of Hooke's law in a Mathcad program. Consistent orientations among individuals were observed in the zygomatic arch and alveolus. The density of cortical bone showed significant regional variation (P < 0.001). The elastic moduli demonstrated significant differences between sites, and a distinct pattern where E3 > E2 > E1 . Shear moduli were significantly different among regions (P < 0.001). The pattern by which chimpanzee cranial cortical bone varies in elastic properties resembled that seen in humans, perhaps suggesting that the elastic properties of craniofacial bone in fossil hominins can be estimated with at least some degree of confidence. Anat Rec, 299:1718-1733, 2016. © 2016 Wiley Periodicals, Inc.

Review of In Vivo Bone Strain Studies and Finite Element Models of the Zygomatic Complex in Humans and Nonhuman Primates: Implications for Clinical Research and Practice.

The craniofacial skeleton is often described in the clinical literature as being comprised of vertical bony pillars, which transmit forces from the toothrow to the neurocranium as axial compressive stresses, reinforced transversely by buttresses. Here, we review the literature on bony microarchitecture, in vivo bone strain, and finite-element modeling of the facial skeleton of humans and nonhuman primates to address questions regarding the structural and functional existence of facial pillars and buttresses. Available bone material properties data do not support the existence of pillars and buttresses in humans or Sapajus apella. Deformation regimes in the zygomatic complex emphasize bending and shear, therefore conceptualizing the zygomatic complex of humans or nonhuman primates as a pillar obscures its patterns of stress, strain, and deformation. Human fossil relatives and chimpanzees exhibit strain regimes corroborating the existence of a canine-frontal pillar, but the notion of a zygomatic pillar has no support. The emerging consensus on patterns of strain and deformation in finite element models (FEMs) of the human facial skeleton corroborates hypotheses in the clinical literature regarding zygomatic complex function, and provide new insights into patterns of failure of titanium and resorbable plates in experimental studies. It is suggested that the "pillar and buttress" model of human craniofacial skeleton function be replaced with FEMs that more accurately and precisely represent in vivo function, and which can serve as the basis for future research into implants used in restoration of occlusal function and fracture repair. Anat Rec, 299:1753-1778, 2016. © 2016 Wiley Periodicals, Inc.

A comparison of three-dimensional stress distribution and displacement of naso-maxillary complex on application of forces using quad-helix and nickel titanium palatal expander 2 (NPE2): a FEM study.

BACKGROUND: Our objectives are to analyse and to compare the stress distribution and displacement of the craniofacial structures, following the application of forces from quad-helix and Nickel Titanium Palatal Expander-2 (NPE2) using finite element analysis. METHODS: Three-dimensional finite element models of young dried human skull, quad-helix appliance and NPE2 were constructed, and the initial activation of the expanders was stimulated to carry out the analysis and to evaluate the Von Misses stresses and displacement. RESULTS: Both the models demonstrated the highest stresses at the mid-palatal suture, with maximum posterior dislocation. The second highest stress was recorded at the fronto-zygomatic suture. The pattern of stress distribution was almost similar in both the groups, but NPE2 revealed lower magnitude stresses than quad-helix. The only exception being quad-helix model showed high stress levels around pterygo-maxillary suture whereas minimal stress around pterygo-maxillary suture was noticed after NPE2 activation. The cusp of the erupting canine and the erupting mesiobuccal cusp of the second molar showed outward, backward and downward displacement signifying increase in their eruption pattern following maxillary expansion. CONCLUSIONS: Maxillary expansion using quad-helix and NPE2 can be used in posterior crossbite correction in cases where maximum skeletal changes are desirable at a younger age; it is furthermore effective in treating young patients with impacted or displaced teeth. Quad-helix and NPE2 produced acceptable forces for orthopaedic treatment even after being orthodontic appliances; their clinical application should be correctly planned as the effects of these appliances are largely age dependent.

The Effects of Desferroxamine on Bone and Bone Graft Healing in Critical-Size Bone Defects.

BACKGROUND: Autogenous bone grafts are still the criterion standard treatment option in critical-size bone defect reconstructions, and many therapies can affect its incorporation. In this study, it was aimed to research the effects of desferroxamine (DFO) application on bone and bone graft healing due to the effects of osteoblast and osteoclast regulation and stimulation of angiogenesis. METHODS: Rat zygomatic arch critical-size bone defect model (5 mm) was used as the experimental model. Thirty-two Sprague-Dawley rats (64 zygomatic arches) were divided into 4 groups (16 zygomatic arches in each). In groups 1 and 2, defects were reconstructed with the bone grafts harvested from the other side, and the right arc was named as group 1, and the left was group 2. At group 1, 200 µM/300 µL dosage of DFO was injected at the zygomatic arch region starting at the seventh day preoperatively and lasting until the 45th day postoperatively. Group 2 animals were defined as the control group of group 1, and 0.9% NaCl injection was applied. In groups 3 and 4, there was no repair after the formation of defects, and the right arc region was treated with DFO, and left was treated with 0.9% NaCl for postoperative 45 days, respectively. Radiological (computed tomography), histological (hematoxylin-eosin), and biomechanical (3-point bending test) tests were used for the evaluation. RESULTS: In radiological evaluation, there was a statistically significant decrease (P < 0.05) in bone defect size in group 3 animals at the 4th, 8th, and 12th weeks, and bone graft volume showed a statistical difference at all weeks (P < 0.05). In histological evaluation, it was observed that there was an increase in osteoblast number and vascularity rates (P < 0.05) in the DFO-treated groups at all weeks. Biomechanical evaluation of the subjects showed increase in bone strength in group 1 animals at 12 weeks. CONCLUSIONS: In this study, it was shown that DFO treatment increased bone graft incorporation and healing in critical-size bone defects. In this aspect, we suggest that DFO can be used to increase graft incorporation in risky areas and reduce the defect size in patients who are not suitable for vascularized bone graft transfer.