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Leontiasis ossea (leonine facies) or cervical canal stenosis are rare complications of polyostotic fibrous dysplasia (PFD). This case report documents dramatic leontiasis ossea in PFD as well as post traumatic cervical cord contusion due to hyperextension injury in a patient with generalized PFD involving the cranio-facial bones, axial skeleton and entire spine with secondary cervical canal stenosis. Cervical cord contusion has not been reported earlier in PFD. [ABSTRACT FROM AUTHOR]

Facial asymmetry after unilateral ankylosis results due to the loss of the condylar growth center on the ankylosed side. This results in the skeletal midline deviating to the affected side, a lack of vertical growth on the same side produces a cant of the occlusal plane and mandibular retrognathism is seen as a result of the hypoplasia. The lower border of the mandibular corpus and angle on the contra lateral side is usually flattened. We report a case of facial asymmetry following unilateral ankylosis, which was treated by a combined approach with distraction osteogenesis and orthodontics. Inexpensive orthopedic finger distractors were used. The facial changes were analyzed using the Grummons facial asymmetry analysis. [ABSTRACT FROM AUTHOR]

Distraction osteogenesis (DO) has been used recently to correct maxillary hypoplasia with predictable and stable results. In patients with clefts of the secondary palate, DO can also be used to aid in vertical alveolus augmentation and rapid orthodontic tooth movement. If an osteotomized dental arch can be transported to a new position without complications, it would reduce or eliminate the need for a secondary bone graft to the cleft alveolus in cleft patients and help prevent dentoalveolar defects by approximating the native alveolar bone and gingiva. Mobilizing a segment in the dentoalveolar region also results in the creation of new bone and attached gingiva. This report shows that the application of DO for skeletal expansion and rapid movement of tooth-bone segments should receive more careful consideration in the treatment of patients with clefts of the palate. [ABSTRACT FROM AUTHOR]

Unlabelled: We report a 13-year-old female patient with multiple congenital abnormalities (microcephaly, facial dysmorphism, anteverted dysplastic ears and postaxial hexadactyly), mental retardation, and adipose-gigantism. Ultrasonography revealed no signs of a heart defect or renal abnormalities. She showed no speech development and suffered from a behavioural disorder. CNS abnormalities were excluded by cerebral MRI. Initial cytogenetic studies by Giemsa banding revealed an aberrant karyotype involving three chromosomes, t(2;4;11). By high resolution banding and multicolour fluoresence in-situ hybridisation (M-FISH, MCB), chromosome 1 was also found to be involved in the complex chromosomal aberrations, confirming the karyotype 46,XX,t(2;11;4).ish t(1;4;2;11)(q43;q21.1;p12-p13.1;p14.1). To the best of our knowledge no patient has been previously described with such a complex translocation involving 4 chromosomes. This case demonstrates that conventional chromosome banding techniques such as Giemsa banding are not always sufficient to characterise complex chromosomal abnormalities. Only by the additional utilisation of molecular cytogenetic techniques could the complexity of the present chromosomal rearrangements and the origin of the involved chromosomal material be detected. Further molecular genetic studies will be performed to clarify the chromosomal breakpoints potentially responsible for the observed clinical symptoms.Conclusion: This report demonstrates that multicolour-fluorescence in-situ hybridisation studies should be performed in patients with congenital abnormalities and suspected aberrant karyotypes in addition to conventional Giemsa banding. [ABSTRACT FROM AUTHOR]

We investigated the frequency, site, amount, and direction of facial asymmetry in human adults with mandibular prognathism and examined if these characteristics were associated postnatally with cardinal clinical signs that may indicate a predisposition to facial asymmetry. Two hundred twenty young Japanese adults (69 men and 151 women) who exhibited skeletal Class III malocclusions were selected. The sample was divided into a Postnatal Factor Group and a Nonpostnatal Factor Group. The former group included those who had: (1) received orthodontic treatment using a chin cap; (2) exhibited clinical symptoms of temporomandibular joint (TMJ) disorder; (3) reported a history of maxillofacial trauma; or (4) radiographic abnormality of the condyles. Subjects with a deviation of more than 2 mm from the facial midline associated with any of the 4 landmarks (ANS, U1, L1 and Me) were classified as asymmetric and the asymmetry was measured on a postero-anterior (P-A) cephalogram. Radiographic facial asymmetry was found frequently (70%-85%, for Menton), and most obviously in the lower jaw (P < .05). Lateral displacement toward the left side of the face occurred more often than right-sided deviation (P < .001, for Menton). However, the Postnatal Factor Group showed a higher proportion of subjects with lateral deviation toward the right side (P = .0031) and a greater amount (P < .0001) of chin deviation. This was due to the fact that the subjects having TMJ problems as a postnatal factor showed no directional uniqueness in jaw deviation and exhibited a longer distance of deviation. [ABSTRACT FROM AUTHOR]

The aim of the present longitudinal cephalometric study was to evaluate the dentofacial shape changes induced by activator treatment between 9.5 and 11.5 years in male Class II patients. For a rigorous morphometric analysis, a thin-plate spline analysis was performed to assess and visualize dental and skeletal craniofacial changes. Twenty male patients with a skeletal Class II malrelationship and increased overjet who had been treated at the University of Heidelberg with a modified Andresen-Häupl-type activator were compared with a control group of 15 untreated male subjects of the Belfast Growth Study. The shape changes for each group were visualized on thin-plate splines with one spline comprising all 13 landmarks to show all the craniofacial shape changes, including skeletal and dento-alveolar reactions, and a second spline based on 7 landmarks to visualize only the skeletal changes. In the activator group, the grid deformation of the total spline pointed to a strong activator-induced reduction of the overjet that was caused both by a tipping of the incisors and by a moderation of sagittal discrepancies, particularly a slight advancement of the mandible. In contrast with this, in the control group, only slight localized shape changes could be detected. Both in the 7- and 13-landmark configurations, the shape changes between the groups differed significantly at P < .001. In the present study, the morphometric approach of thin-plate spline analysis turned out to be a useful morphometric supplement to conventional cephalometrics because the complex patterns of shape change could be suggestively visualized. [ABSTRACT FROM AUTHOR]

The article presents information on focal dermal hypoplasia. While the etiology of the disorder is unknown, it is known that nearly 90% of patients are female. The article discusses how the disorder is physically manifested in patients, noting that bone development is impaired with patients often having abnormalities with their hands, feet and facial development. Teeth and enamel can be impacted and higher risks of dental caries are associated with the disorder. Information on diagnosing the syndrome is presented along with guidelines for treatment.

Dentofacial deformities of the jaws, teeth and middle and lower thirds of the face affect both function and appearance. Epidemiological studies show that many Americans suffer from a malocclusion, which alters the proportions of the face. Moreover, in about 5 per cent of cases, the deformity is great enough to cause a severe handicap. A number of years ago, only orthodontic therapy was available, its aim being to achieve an acceptable occlusal relation while improving appearance as much as possible. However, this therapy provided limited improvement. Consequently, serious cases were later treated surgically. Since the 1970s, new surgical techniques have made it possible to reposition the jaws or dentoalveolar segments. As a result, today many more cases are treated in collaboration with orthodontists and surgeons. This article summarizes the main orthognathic surgical techniques, their procedures and their effects on temporomandibular disorders. [ABSTRACT FROM AUTHOR]

Immunodeficiency-centromeric instability-facial anomalies (ICF) syndrome is a condition characterized by variable combined immunodeficiency, developmental delay, facial anomalies and a variety of structural chromosomal rearrangements. Recently, aberrations at the molecular level have been described consisting of alterations in the methylation pattern of classical satellite DNA. To our knowledge 15 subjects have been described so far in the literature showing marked phenotypic variability. We report on two new patients with normal development and some peculiar clinical and immunological manifestations. All patients previously reported in the literature are reviewed. CONCLUSION. The identification of these two cases among our hypogammaglobulinaemic patients suggests that ICF syndrome is not a rare disorder and it should be always taken into account in immunodeficient patients with facial abnormalities. [ABSTRACT FROM AUTHOR]

A 30-month-old boy with severe psychomotor retardation and numerous developmental anomalies, such as small trigonocephalic head, craniofacial anomalies, malformations of fingers with hypoplastic thumbs, anomalies of urogenital organs and imperforate anus, is presented. Cytogenetic studies of peripheral blood lymphocytes with differential staining of chromosomes revealed 46,XY,r13 karyotype. The correlation between clinical features and the observed chromosome aberration is discussed. Hitherto unreported developmental brain anomalies with partial exhibited skeletal abnormalities, some not reported previously. [ABSTRACT FROM AUTHOR]

Measurement of various craniofacial structures was compared with clinical assessment of craniofacial anomalies. Different diagnostic groups of children were studied. Anomalies were seen more often in patients with congenital heart defect, mental retardation and multiple congenital anomalies syndromes than in control children. Comparative study of quantitative data and qualitative (clinical) assessment showed some agreement but also many discrepancies. Therefore, in describing craniofacial anomalies both methods should be used. This is particularly true in the differential diagnosis of multiple congenital anomalies syndromes and variant familial developmental patterns. [ABSTRACT FROM AUTHOR]

Baraitser-Winter syndrome (BWS), first reported in 1988, is apparently due to genetic abnormalities that are still not well-defined, although many gene abnormalities are already discovered and de novo missense changes in the cytoplasmic actin-encoding genes (called ACTB and ACTG1) have been recently discovered. The syndrome combines facial and cerebral malformations. Facial malformations totally or partially present in the same patient are: Iris coloboma, bilateral ptosis, hypertelorism, broad nasal bridge, and prominent epicanthic folds. The various brain malformations are probably responsible for growth and mental retardation. To the best of our knowledge, the syndrome is very rare as few cases have been reported so far. Our aim was to describe a child with a phenotype that looks like BWS with proved partial growth hormone (GH) deficiency which was not reported before. A girl aged 7-year-old of consanguineous parents was referred for short stature and mental retardation. Clinical examination showed dwarfism and a delay in her mental development. Other clinical features included: Strabismus, epicanthic folds, broad nasal bridge, and brain anomalies such as lissencephaly, bilateral hygroma, and cerebral atrophy. Hormonal assessment showed partial GH deficiency without other endocrine disorders. Our case looks exactly like BWS. However, apart from facial and cerebral abnormalities, there is a partial GH deficiency which can explain the harmonious short stature. This case seems worth to be reported as it adds GH deficiency to the very rare syndrome. [ABSTRACT FROM AUTHOR]

It is now increasingly evident that chromosomal abnormalities underlie a goodly proportion of congenital abnormalities, between 5 and 15 per cent of children with congenital abnormalities showing evidence of chromosomal deletions or aberrations. Since dentofacial defects are particularly common in developmental abnormalities, and to an extent not in accordance with the concept of stage-specificity, the possible chromosomal basis of dentofacial defects represents a problem in its own right and, when the chromosomal type is known, provides new indications as to the role of chromosomes in controlling developmental timing. [ABSTRACT FROM AUTHOR]

Meaningful analysis of cephalofacial growth depends upon the relevance of the diameters, angles, and ratios actually employed. Their applicability to general growth problems can be tested in specific syndromes where growth is markedly altered in part of the face. Such syndromes constitute natural experiments that can test the discriminatory efficiency of measures thought to be useful. The pediatric radiologist and the plastic surgeon together see many such examples. For some syndromes conventional measures fail to discriminate. Others, involving growth abnormalities affecting only part of the face, suggest new measures that may eventually have wide applicability. The orthodontic patient, moreover, constitutes a transitional sequence from the clinically "normal" to the syndromes here described. Acquaintance with the latter may illuminate the former, particularly as the nature of the growth disproportions becomes more clearly understood. [ABSTRACT FROM AUTHOR]

Down's disease, involving an extra chromosomal segment, represents a further natural experiment bearing on dental and facial growth. Agenesis of I2 and other teeth is common, but the incidence of number reduction in the parents needs to be known. Abnormalities in tooth formation timing has been suggested. Ideally, the unaffected siblings should be used as controls. Growth of the skull base and face is characteristically altered, providing an opportunity to test cephalometric parameters. Besides the interest in chromosomal abnormality itself, Down's disease, that is, "Mongolism," has great potential bearing on the determinants of normal dentofacial development. [ABSTRACT FROM AUTHOR]

Binder's Syndrome is a congenital malformation characterized by nasomaxillary hypoplasia. It can be isolated or associated with multiple aetiologies, such as maternal intake of coumarin-based anticoagulants during pregnancy, systemic lupus erythematosus and some other monogenic conditions, such as Keutel syndrome or Chondrodysplasia punctata (CDP). [1] This article is protected by copyright. All rights reserved. [ABSTRACT FROM AUTHOR]

• Spreads awareness about a bonafide rare syndrome to practitioners involved in care of the head and neck region. • Reports, perhaps the first manifestation of this syndrome in the maxillofacial region. • Emphasises GDP role in systemic care. • Adds a differential diagnosis to neuropathies in examination of the head and neck region. • Emphasises the importance of history taking, examination and timely referral practices. [ABSTRACT FROM AUTHOR]

Abstract: The congenital vomer defect (CVD) is a rare and still partially unknown condition. Only few cases have been reported in the international literature and the large majority of them appeared to be isolated. We report a case of CVD detected in a 7-year-old girl affected by ectodermal dysplasia clefting syndrome caused by a mutation of the TP63 gene. [Copyright &y& Elsevier]

Fibrous dysplasia is a bone pathology characterised by abnormal differentiation of osteoblasts leading to replacement of normal marrow and cancellous bone by immature bone and fibrous stroma. A case report of a 20-year-old female patient with a chief complaint of a swelling in the right upper back tooth region, of 6 months duration which was diagnosed as an immature fibrous dysplasia is presented. [ABSTRACT FROM AUTHOR]

Background: Macrostomia as a rare facial deformity is classified among facial clefts. It originates from failure in union of maxillary and mandibular prominences of first brachial arch during 7th embryonic week. Case Presentation: We report a case of bilateral macrostomia (bilateral lip cleft) in a female newborn as a sole entity without other skeletal and facial deformities. The cleft was repaired by a simple linear triangular flap using extra oral landmarks to locate lip commissures. Patient was followed through a six-month period. Acceptable results were gained in mouth appearance as well functional aspects. Conclusion: Commissural repair through a linear flap can result in minimal visible scar with satisfying results in both esthetics and functional aspects. [ABSTRACT FROM AUTHOR]

Abstract: Background: Cleft lip and palate patients often present wide alveolar cleft and midface hypoplasia. Closure of such wide alveolar clefts may be difficult using bone graft. Traditional orthognathic surgery for midface advancement shows relapse. Distraction osteogenesis (DO) as a modality for midface advancement has shown good results with external distractors. Use of internal distractor (ID) further improves patient compliance, causes minimal discomfort and offers the advantage of limiting relapse. The purpose of this study was to evaluate the versatility of intraoral distracters in midface advancement in cases with alveolar cleft. Method: A 16 years old young girl with midface deficiency and alveolar cleft visited our outpatient clinic for aesthetic improvement and midface distraction was planned. After Le Fort I osteotomy, internal distractor was fixed. A latency period of 5 days was allowed and then distraction was started at the rate of 1 mm per day in two installments. Evaluation was done for closure of cleft, ease of the procedure, stability, and complications. Lateral cephalograms were evaluated at three stages: predistraction; post-distraction; and 1 year post-distraction. Results: Complete closure of alveolar cleft was observed with 17 mm midface advancement and bone formation at the pterygomaxillary region. Maxillary position improved in relation to the cranial base. The results were stable even at 1 year follow-up. Conclusion: Distraction osteogenesis using intraoral distractors was successful in alveolar cleft closure, as well as midface advancement in terms of stability of results and patient compliance with minimal complications. [Copyright &y& Elsevier]

Oro-facio-digital syndrome (OFDS), a group of congenital anomalies, is characterized by malformations of the oral cavity (cleft palate, high arched palate, tongue lobulation, hamartoma on the tongue), face (frontal bossing, facial asymmetry, hypertelorism), and digits (syndactyly, brachydactyly, polydactyly). OFDS I is an X-Iinked dominant condition. OFDS I is a rare syndrome, occurring in approximately i/250,000 live births. Being a rare entity, this paper presents a case of OFDS I. [ABSTRACT FROM AUTHOR]

Abstract: A 3-month-old male patient presented to the maxillofacial department in Al-Amiri Dental Center, Kuwait, with a facial deformity. There was no family history of any systemic illness or abnormalities nor consanguinity. On examination; the patient had a transverse incomplete facial cleft on the right cheek, the maxilla and the upper lip were duplicated and translocated to the right lower jaw and lip, with all components of mucosa as well as a complete compliment of deciduous teeth. There was unilateral macrosomia as well as cleft of the secondary palate and triple uvulae. The mandible had restricted mobility. Photographs and a Computerized Axial tomogram (CAT scan) were taken and a complete work up to exclude congenital cardiac disease was also done. The surgical approach, and possible future operations were explained in detail and discussed with the parents. Their consent was taken. [Copyright &y& Elsevier]

Abstract: Fibrous dysplasia is an osseous growth disorder, producing immature bone characterized by the replacement of normal bone with fibro-osseous connective tissue. The therapy is surgical, but the diagnosis of fibrous dysplasia of the craniofacial bones is not in itself an indication for treatment. The authors present a rare case of a zygomatic arch localization of fibrous dysplasia causing considerable facial asymmetry and social impairment. The clinical and radiological features are presented, the surgical procedure and indications are then described and the histopathological findings are discussed. [Copyright &y& Elsevier]

A girl presented at 6 weeks of age with failure to thrive and arching of the back. She had various dysmorphic features, hepatosplenomegaly, and developmental delay. The electroencephalogram and cranial ultrasound were abnormal, and a computed tomogram showed lissencephaly and apparent agenesis of the corpus callosum. Because of frequent aspiration she became oxygen dependent. She later developed intractable convulsions and died at the age of 9 months. [ABSTRACT FROM AUTHOR]

The article describes the case of a 45-year-old man with synchronous lesions of the right accessory parotid gland (APG) and left main parotid gland (MPG). Topics discussed include tumor with homogeneous enhancement arising from the left deep parotid lobe, epithelial/myoepithelial carcinoma, and computed tomography scans showing contrast-enhancing lesions of the right APG and left MPG.

Background: Leontiasis ossea is a rare medical condition, with characteristic overgrowth of the facial and cranial bones. Reports about this uremic complication are less frequently reported, probably due to better dialysis and better medical control of secondary hyperparathyroidism. Description of case: We report the case of a 36-year-old female patient who had been treated with chronic hemodialysis and who developed secondary hyperparathyroidism. Conclusion: In noncompliant patients with uncontrolled secondary hyperparathyroidism uremic leontiasis may develop in which case the treatment is rarely successful or may even be contraindicated due to other comorbid conditions. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented which is concerned with otocephaly and prenatal and postnatal imaging findings.

In this article the author discusses the use of high-density polyethylene (HDPE) implants during facial skeletal augmentation in India. The author states that exposure to HDPE implants is dangerous since it needs to be removed and replaced with an autogenic material. The author also mentions that a silicone implant has a tendency to be mobile while the HDPE implant does not appear to look and feel good.

Copyright of Revue de Stomatologie & de Chirurgie Maxillo-Faciale is the property of Masson SPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents a case study of a 25-year-old Asian woman who delivered a female infant with a congenital malformation such as proptosis, micrognathia and the absence of nasal bone. The baby was intubated at birth, but died on day three of life due to respiratory acidosis. Both parents did not agree with post-mortem or generic testing. The article discusses a rare genetic disorder known as Pfeiffer's Syndrome, its clinical subtypes and diagnosis.

The article focuses on the issue concerning long-face syndrome. It cites the problem faced by orthodontists, oral surgeons, and otorhinolaryngologists on the diagnosis and treatment of long-face syndrome. It also discusses several papers on the management of the syndrome including surgical and non-surgical approaches.

The author shares his insights on craniofacial stem cell therapy. Issues raised include the causes of cranio-maxillofacial skeletal defects, the role of craniofacial tissue engineering in craniofacial reconstruction, and an overview of a case series that utilized in situ ossification using adipose stem cells as a source of autogenous mesenchymal stem cell.

Introduction: Down syndrome (DS) is known to be often (30–50%) comorbid with sleep disordered breathing (SDB) for their facial anatomical deformation, muscular hypotonia. Daytime sleepiness resulted from SDB may relate to impaired cognitive function even in general public. In DS, congenital heart diseases (CHD) are also highly complicated (30–60%). Such CHD and SDB may cause a vicious cycle and early intervention to SDB in DS would contribute to their better intellectual and physical development. We reported that some of the DS slept in unusual postures. Thus, we studied the mutual relation among them in DS. Materials and methods: We recruited 90 caregivers of the DS in Fukuoka. The questionnaires for the DS contained demographic descriptions including CHD, sleeping postures, Epworth sleepiness scale (ESS), and SDB symptoms (easiness of getting to sleep, snoring, arousal, witnessed apneic episodes, nocturnal urination, nap, hardness of awakening). We calculated individual Caup index (0–5yo), Rhorer index (6–13yo), and BMI (14-yo) for judging obesity. We analyzed the relation between SDB symptoms and these items using chi-square test. Results: Seventy of 90 DS (34 men, 18 10yo) responded to the survey. Thirty-seven DS (53%, 15 men, 15 9yo) had CHD. Symptoms of SDB were as follows: “easiness of getting to sleep” in 90%, “snore” in 75%, “nocturnal arousal” in 52%, “witnessed apneic episodes” in 40%, “night urination” in 19%, “nap” in 41%, “hard to awaken” in 15%. There was significantly higher proportion of obese DS in “hard to awaken” than in “easy to awaken” (78% vs. 33%, P <0.05), and tendency of higher proportion of unusual sleep postures in “easy to awaken” than “hard to awaken” (67% vs. 33%, P <0.1). Furthermore, higher ESS was in “nocturnal arousal” and “night urination” than in “no arousal” and “no night urination” (38% and 55% vs. 4% and 13%, P <0.01, respectively). Finally, there were tendencies of higher comorbidity of CHD in those with SDB symptoms. Conclusion: Preventing obesity seems to be useful to improve SDB also in DS. The complication of CHD in the DS with SDB suggested formation of the vicious cycle. The unusual sleeping postures in the DS seem to be self-defending behaviors to protect from SDB. In conclusion, we need not only to take general care of SDB like reducing weight but also to give attention to specific risk factors of SDB in DS. Acknowledgements: Our deepest appreciation goes to the members of the Fukuoka branch of Japan Down Syndrome Society. [Copyright &y& Elsevier]

The author discusses the significance of case selection in relation to craniofacial applications of distraction osteogenesis (DO). He emphasizes the importance of considering the complex structure and anatomy of facial bones when considering DO. He asserts that using DO is not recommended for a case that can be managed effectively by a conventional technique such as osteotomy.

Summary: The buttress is the cornerstone of the midface both functionally and aesthetically. Therefore, fracture of the buttress requires surgery. A patient wanted cosmetic surgery simultaneously with a reduction of facial bone fracture. To achieve this, we reconstructed the defect of the maxillary buttress using the remnant bone of the mandible angle ostectomy. A 27-year-old man presented with a left maxilla fracture and defect at the maxillary buttress. Since the patient was considering cosmetic surgery to alter his square face, we planned a mandibular angle ostectomy and used the remnant bone as an onlay bone graft for maxillary reconstruction. There was no complication and the patient was satisfied with both the functional and aesthetical look of the reconstructive surgery. We reconstructed the defect of the maxillary buttress successfully using the remnant bone of the mandible angle ostectomy. Although this technique cannot be applied to every patient, reconstruction of facial bone defects with the remnant bone of the mandibular angle ostectomy may be a potential option in some cases. [Copyright &y& Elsevier]

Abstract: Introduction: Treatment of skeletal Class III malocclusion with an anterior crossbite is challenging due to unpredictable results and potentially unfavorable growth. Growth modification in growing patients is an alternative approach to orthognathic surgical correction. Objective: Case report of a patient with Class III malocclusion and anterior crossbite was treated with maxillary protraction facemask to illustrate that treatment has to be started during growth period and patient compliance is a determining factor. Treatment procedure: Treatment of anterior crossbite was completed in two phases. The first phase was to correct the skeletal discrepancy with rapid palatal expansion, miniscrews and protraction facemask. The second phase was to correct the dental alignment with fixed orthodontic appliance. Conclusions: Protraction facemask therapy started at growing age with good patient compliance is a good approach in treating anterior crossbite relating to skeletal problems in the mixed dentition period. [Copyright &y& Elsevier]

Substantial and innovative developments in the field of bone tissue engineering have prompted increased demand for suitable pre-clinical large animal models. The pig has several advantages over other non-primate species, including availability, rapid growth, large litters, and similar anatomy and physiology to humans. These characteristics make them ideal models for research in diverse applications such as cardiovascular disease, pharmacological activity testing, and organ transplantation. There has been an increased interest in the use of swine as a model for bone healing and grafting techniques. Maxillofacial surgeons strive to develop the best therapy for large bone defects in the face resulting from tumour resection, congenital abnormalities, and traumatic injuries. Creating a model to study a critical-sized bone defect in the mandible, which does not spontaneously heal without clinical intervention, would be a method to test growth factors and synthetic bone graft therapies. However, the size of bone defect required to create this condition has not been ascertained. In the current study, we examined the in vivohealing response for 4, 8, and 16 weeks of surgically created bone defects in the posterior region of the pig mandible. Yorkshire barrows (n=12) 6–7 months of age were used for the study. All animal experiments conformed to the University of Illinois Institutional Animal Care and Use Committee (IACUC) guidelines. Animals were maintained under general anaesthesia and transcortical, circular defects with diameters of 6, 10, 16, or 25mm were created on both sides of the mandible. The presence and amount of calcified tissue was assessed using radiographs and dual energy x-ray absorptiometry (DEXA). Tissue morphology was examined using hard-tissue histological methods and a light microscope. Defect diameters of 6, 10, and 16mm had completed healing or were in the process of healing within the 16-week timeframe of the study. Compared to controls, average percent differences in bone mineral density, in order of increasing defect size, were 0.62%, 28.1%, and 54.5%, respectively. In contrast, 25mm diameter defects displayed limited collagenous tissue ingrowth, and the presence of calcified tissue was not detected, as indicated by radiographs and histological staining. As the defect size increased, the time required to heal was prolonged until a critical size was determined and normal bone was not completely regenerated. In conclusion, circular defects in the posterior region of the pig mandible with diameters equal or greater than 25mm will result in limited healing without additional medical intervention and can be termed critical-sized defects. This porcine model will allow for the rapid development and testing of new approaches for the repair of damaged bone, which is especially prevalent in the craniofacial area. This work was partially supported by the Carle Foundation Hospital (#2007-04072) and the Illinois Regenerative Medicine Institute (IDPH #63080017). [ABSTRACT FROM AUTHOR]

The article focuses on problems in analyzing data on dentofacial anomalies. It states that problems in analyzing craniofacial data include selecting relevant observations that express trends and variations of size and form in the craniofacial complex, the problem with measurement error caused by radiographic projections of soft tissue thickness, and understanding the complexities of multivariate analysis methods that are used. It comments on improving the accuracy of regression calculations.