Mandibular Cortex Research Articles

Orbit and Maxilla Augmentation of Oblique Facial Clefts Using Mandibular Outer Cortex

This study focused on using the mandibular outer cortex for orbital and maxillary augmentation of oblique facial clefts. Eight oblique facial clefts were reconstructed with the mandibular outer cortex from April 2000 to April 2008. No visible scars and few complications were observed at the donor site. Postoperative follow-up for 6 months to 3 years demonstrated that all of the patients had good aesthetic facial appearances. The mandibular outer cortex can be used for orbital and maxillary augmentation of oblique facial clefts.

Narrowing and sliding genioplasty procedure combined with mandibular outer cortex ostectomy technique to correct square jaw in short face

To evaluate the the feasibility and effectiveness of narrowing and sliding genioplasty combined with mandibular outer cortex ostectomy technique to reshape a square jaw in short face. From July 2005 to October 2009, a total of 57 patients received narrowing and sliding genioplasty combined with mandibular outer cortex ostectomy procedure to correct square jaw in short face. All the patients had standard frontal and lateral cephalometric radiographs, panoramic radiographs, and were photographed preoperatively and postoperatively to assess their face contour. The alteration of mandibular angle, mental contour and width of lower face was observed for 6 to 24 months postoperatively. Questionnaires were used to assess the patients' satisfactory. It showed that the postoperative lower face had narrowed and become softer, slender and oval, with a slick mental region. The final aesthetic outcomes were quite satisfactory in all cases from both the view of surgeons and patients. Narrowing and sliding genioplasty combined with mandibular outer cortex ostectomy procedure could efficiently adjust the shape and position of chin to obtain a good proportion of the lower face, and to change square and short face to slender oval one by single operation in accordance with the fashionable aesthetics in orientals.

Mandible Changes Evaluated by Computed Tomography Following Botulinum Toxin A Injections in Square-faced Patients

A facial contour that is oval is more pleasing in Asian women. Patients with a square face often seek facial contouring procedures to improve their appearance. Treatment often involves various combinations of Botulinum NeuroToxin A (BoNTA) injections into the masseters and/or mandibular angle resection. Many physicians claim that muscle paralysis with injections alone will decrease pulling on the underlying bone and also treat underlying bony flaring when present. Muscular changes after BoNTA injections have been well documented. However, the effect of BoNTA injections on the underlying mandibular bone morphology has not been studied to the best of the authors' knowledge. The goal of this study was to determine whether there are mandibular changes after masseter injection with botulinum toxin. In this retrospective study of ten female patients seeking treatment for a square face, three-dimensional CT scans were taken before and 3months after standardized BoNTA injections in bilateral masseters. Mandibular cortex thickness, mandibular bone thickness, and mandibular volume were measured. Soft-tissue changes were observed but no bony changes were observed 3months after injections. In this study of adult patients, there were no statistically significant mandibular changes 3months after BoNTA injection. The current theory of mandibular flaring resolution after partial muscle paralysis is not supported by our findings. Therefore, a patient presenting both masseteric hypertrophy and bony flaring will most likely require a combined muscular and bony procedure.

Cortical porosity of the mandible in an osteoporotic sheep model

Cortical porosity and thickness of the axial and the appendicular skeleton are predictors of osteoporotic fractures. In the jawbone, however, cortical porosity and thickness may affect the mechanical stability of dental implants. We have shown previously that the jawbone of osteoporotic sheep has impaired trabecular structures, but whether catabolic bone turnover also accounts for the cortical bone porosity remains unknown. We compared mandibular bone from six geriatric sheep subjected to ovariectomy, calcium/vitamin D restriction, and methylprednisolone administration to those of six healthy adult control sheep. Histological ground sections were prepared from the diastema, first and second premolars, and postmolar region. Cortical porosity and thickness were assessed by histomorphometry. Cortical porosity was higher in osteoporotic sheep than in adult controls in the diastema and in the first and second premolar region. In the postmolar region, the difference failed to reach the level of significance. The changes were even more prominent when histomorphometry was restricted to the inner millimeter of the mandibular cortex. In contrast, induction of osteoporosis did not have a discernable effect on cortical thickness. These results demonstrate that cortical porosity of mandibles is more pronounced in geriatric osteoporotic sheep than in adult controls.

Effect of outer mandibular cortex osteotomy on local morphology and biomechanics in young miniature pigs

Aim The purpose of this study was to research the effect of outer mandibular cortex osteotomy on local morphology and biomechanics in young miniature pigs. Methods Eight 3-month-old miniature pigs were used as experimental animals to establish an animal model for removing the outer cortex of the mandibular body, and the changes in local morphology, fine structure, and biomechanics of the mandible after the operation were evaluated. Results The thickness of the operated side decreased to a greater extent than that of the control side. Further, local histologic structure and biomechanics characteristics could be recovered under stress conditions and were close to those of the normal side after the operation. However, some animals (37.5%) exhibited mandible deviation after operation. Conclusion Under normal conditions, mandibular outer cortex osteotomy should not be performed in the case of children.

A pilot study to evaluate the invasiveness of mandible ameloblastoma on ultrasonography

Objective To evaluate and demonstrate ultrasonographic characteristics of mandibular ameloblastoma with active proliferation. Methods Nineteen subjects with ameloblastomas in the mandibles were examined with ultrasonography. In addition to sizes,internal echoes,the research was focused on blood flow of the tumors and destruction of mandibles. Ultrasonographic appearances of the tumors were compared with histopathological findings. Sensitivity and specificity of Doppler flow signals and destruction of mandibles for prediction of active tumor proliferations were calculated. Results Fifteen cases (79%)showed no or minimal flow signals on color Doppler flow imaging(CDFI), whereas the remaining 4 lesions demonstrated abundant flow signals,in which 3 cases were confirmed histopathologically with active tumor proliferations. The sensitivity and specificity of the Doppler flow signals for prediction of active tumor proliferations were 100% and 94%, respectively. Fourteen cases (74%) showed the mandibular cortices were thin but continuous,among the remaining 5 lesions showed local cortices destruction,3 of them were confirmed histopathologically with active proliferations. The sensitivity and specificity of the destruction of cortical bone for prediction of active tumor proliferations were 100% and 88 %, respectively. Conclusions Ultrasonography can be used as a new effective supplementary diagnostic method for mandibular ameloblastomas. CDFI of tumor vascularity and destruction of cortical bone could be used to predict active tumor proliferations and invasiveness. Key words: Ultrasonography,Doppler,color; Mandible; Ameloblastoma

Mandibular Periostitis Ossificans in Immature Large Breed Dogs: 5 Cases (1999–2006)

This case series describes clinical, radiographic, and histopathological features of mandibular swellings in 5 immature, large breed dogs. The dogs originated from different regions of the United States. In each case, intraoral dental radiography of the jaw swelling revealed a two-layered (double) ventral mandibular cortex. Biopsy was performed in 4 of the 5 puppies, revealing periosteal new bone formation. Resolution of the mandibular swelling was spontaneous in the 4 dogs available for follow-up examination. The authors postulate that the clinical, radiographic, and histopathological presentation of mandibular swelling in these 5 dogs is a distinct pathological entity consistent with an inflammatory condition of the maturing human mandible known as periostitis ossificans.

Reconstruction of Old Orbital Wall Fractures With Mandibular Outer Cortex

This study focused on using the mandibular outer cortex in the reconstruction of old orbital wall fractures. Old orbital wall fractures of 46 patients were reconstructed with the mandibular outer cortex. The surgical results were evaluated by performing clinical follow-up and by measuring the changes in the orbital volume. Donor-site complications were also evaluated. All patients had good aesthetic and functional results, with an accurate repair of orbital wall defects and the restoration of orbital volume. There were no obvious major donor-site complications. The mandibular outer cortex can be used for the reconstruction of old orbital wall fractures.

Juvenile ossifying fibroma of the mandible: a case report.

ABSTRACTBackgroundFibro-osseous lesions of the jaws, including juvenile ossifying fibroma, pose diagnostic and therapeutic difficulties due to their clinical, radiological and histological variability. The aim of this study was to report the outcome of a 9 years old girl with diagnosed juvenile ossifying fibroma treatment.MethodsA 9 years old girl presented with a 6 x 8 cm sized hard fixed tumour on right ramus and corpus of the mandible. On the radiological examination tumour showed an irregular but well bordered, unilocular and expansive lesion on the right corpus and ramus of the mandible. There was no teeth displacement or teeth root resorbtion. Microscopically, the tumour had trabeculae, fibrillary osteoid and woven bone. After the clinical, radiological (panoramic radiography, computed tomography and magnetic resonance imaging) and histologic analysis it was diagnosed juvenile ossifying fibroma. In the history of the patient there has been an acute lymphocytic leukaemia in the remission for 3 years.ResultsBecause of large size of mandibular tumour, resultant expansion and destruction of mandibular cortex, the patient underwent right hemimandibulectomy using transmandibular approach. There was no recurrence or complications for two years follow-up.ConclusionsAlthough juvenile ossifying fibroma is an uncommon clinical entity, its aggressive local behaviour and high recurrence rate means that it is important to make an early diagnosis, apply the appropriate treatment and, especially, follow-up the patient over the long-term.

Correction of low angel-square jaw with mandibular "V-Line" ostectomy combined with mandibular outer cortex ostectomy

To evaluate the feasibility of mandibular "V-Line" osteotomy combined with mandibular outer cortex osteotomy for correction of low angle-square jaw. From Jul. 2005 to Nov. 2007, 31 patients with low angle-square jaw were corrected with mandibular "V-Line" osteotomy combined with mandibular outer cortex osteotomy. The patients were followed up for 6-24 months. Pre- and Post-operative standard images and X-ray cephalometric examination were used to assess the therapeutic effect. The wounds were healed primarily in all the 31 cases with no severe complication. The lower labial numbness was happened in 13 cases, which was recovered within 4 months. All the patients achieved esthetic improvement at the frontal and lateral view. The mandibular angle and the mandibular plane angle reached 110 degrees - 120 degrees and 25 degrees - 30 degrees after operation. The distance between the angles was decreased. The low angle-square jaw can be corrected satisfactorily with mandibular "V-Line" osteotomy combined with mandibular outer cortex osteotomy.

Correlations between seven panoramic radiomorphometric indices and bone mineral density in postmenopausal women

The aim was to test for correlations of 7 panoramic radiomorphometric indices with lumbar spine and hip bone mineral densities (BMDs) and to test the accuracy of these indices for predicting osteoporosis and a T-score < or =-2.0. Mandibular cortical indices, simple visual estimations of cortical widths, mental and antegonial indices, antegonial depth, gonial and antegonial angles, and BMD were measured in 351 postmenopausal women. Associations were demonstrated between BMDs, qualitative indices, and cortical measurements. In the case of severely eroded mandibular cortices, the odds ratio (OR) for osteoporosis (according to the World Health Organization criteria) was 4.82 and the OR for a T-score < or =-2.0, the threshold to begin treatment, was 10.87. In the case of very thin mandibular cortices, the ORs were 8.02 and 5.46 for osteoporosis and a T-score < or =-2.0, respectively. The mental index cutoff for osteoporosis was 3.15 mm. Antegonial indices and gonial angles cannot be used as osteoporosis predictors. The most accurate indices were the mental index, mandibular cortical index, and visual estimation of cortical width.

Correction of square jaw with low angles using mandibular “V-line” ostectomy combined with outer cortex ostectomy

The objective of this study was to evaluate the feasibility and effectiveness of correction for square jaw with low angle using mandibular "V-line" ostectomy combined with outer cortex ostectomy. From July 2005 to November 2007, 31 patients who had square faces with low angles were treated with mandibular "V-line" ostectomy combined with mandibular outer cortex ostectomy. All the patients had standard frontal and lateral cephalometric radiographs, panoramic radiographs, and were photographed preoperatively and postoperatively to assess their face contour. The alteration of mandibular angle and width of lower face was observed for 6 to 24 months postoperatively. Postoperative appearance of all 31 cases showed that the width of lower face was reduced expectedly; the gonial angle and the mandibular plane angle were increased effectively. The final aesthetic outcomes were quite satisfactory in all cases for both the surgeons and the patients. A slender oval facial outline as the fashionable aesthetics could be achieved by using mandibular "V-line" ostectomy combined with mandibular outer cortex ostectomy. It might be a feasible and a reasonable surgical procedure for correction of square jaw with low angle.

Bisphosphonate-related osteonecrosis of the jaw: clinical correlations with computerized tomography presentation

The aim of this study was to correlate clinical and computerized tomography (CT) features of bisphosphonate-related osteonecrosis of the jaws (BRONJ). All ONJ patients for whom there was complete CT scan imaging were eligible. Selected clinical parameters retrieved from their medical records were analyzed for correlation with CT parameters. The clinical presentation of BRONJ was supported by findings in CT imaging in 78.3%. The lesion's size on CT correlated with the presence of purulent secretion (p = 0.03). When sequestrum was present, the median lesion's size on CT was relatively big (28 mm, range 21-43 mm). The mandibular canal cortex was never breached. CT has reasonable detection competence for diagnosing BRONJ. Purulent secretion indicates the likelihood that a more extensive involvement will be displayed on CT. A large lesion on CT should raise the index of suspicion for sequestrum. The CT appearance of a continuous cortex of the mandibular canal may serve as a differential parameter between BRONJ and metastasis to the jaw.

Relationship between the mandibular inferior cortex and bone stiffness in elderly Japanese people

SUMARRY: This study assessed the relationship between the mandibular inferior cortex (MIC) and bone stiffness in elderly Japanese subjects. Results suggest that MIC classification may be useful for screening patients for the possibility of osteoporosis by measuring bone stiffness with ultrasound bone densitometry. The prevention of fractures is a priority for patients with osteoporosis. Dental panoramic radiographs are frequently taken for the examination of teeth and jaws in general dental practice worldwide. This study assessed the relationship between the mandibular inferior cortex (MIC) and bone stiffness in elderly Japanese subjects. This study included 519 healthy subjects (263 men and 256 women) aged 70 years old. We evaluated the relationship between MIC classification and bone stiffness using Scheffe's multiple comparison test. Multiple linear regression analysis was used to assess the relationship between MIC classification and bone stiffness after controlling for confounding factors. A significant correlation was found between MIC classification and bone stiffness in men (C1 vs C2: p < 0.05) and women (C1 vs C2: p = NS, C1 vs C3: p < 0.01, C2 vs C3: p < 0.05). MIC classification was significantly associated with bone stiffness on multiple linear regression analysis after controlling for sex, body mass index, regular exercise, and smoking (beta = -0.11, p < 0.01, R(2) = 0.387, p < 0.001). Our study suggests that MIC classification may be useful for screening patients for the possibility of osteoporosis by measuring bone stiffness with ultrasound bone densitometry.

Osteoporosis and oral bone resorption: a review

This paper is a summary of the published studies on the possible association between osteoporosis and alveolar bone loss. Osteoporosis and low bone mass are considered as a major public health problem. The mandible like other bones of the body has a series of anatomical landmarks that can serve as radiographic indicators. Using these indicators it is possible to evaluate changes in bone with respect to its quantity or quality by different methods of taking images. Higher bone resorption was detected in women with a higher number of pregnancies. Also, the higher educated the patient, the less bone resorption. Women with a background of backaches had more bone resorption to those who did not have this backache background. Finally, it was recognized that it would be possible to clear the quality dimension of the process of mandibular bone resorption. If we can identify the osteoporotic process using a basic panoramic radiography measurement technique, then it is possible to intercept the progress of the disease through early warning and treatment. From the results of this study, it can be concluded the thickness of the mandibular angular cortex can be used as an index for bone resorption. A healthy lifestyle has multiple benefits for the mouth and throughout the body. Dental professionals can play a role in preventing osteoporosis by reinforcing this message.

Dental and radiographic findings as predictors of osteoporosis in postmenopausal women

The objective of this study was to evaluate the relationship between dental findings and osteoporosis in postmenopausal women. One hundred and eight postmenopausal women were recruited for the study. All participants underwent dual X-ray absorptiometry (DXA). The number of remaining teeth, clinical attachment loss, pocket depth and mobility of each tooth were determined. Radiodensitometric analyses were performed on digital periapical radiographs utilizing an aluminum stepwedge technique. The appearance of inferior mandibular cortex posterior of the mental foramina region was scored according to the classification by Klemetti. The number of remaining teeth, attachment loss values, Klemetti Index scores and the radiodensitometric scores showed a significant relationship with skeletal bone density. Tooth loss, an increased clinical attachment level, reduced density on digital periapical radiographs and an eroded appearance of the inferior mandibular cortex in panoramic radiographs are associated with low-skeletal bone mineral density.

Relation of bone turnover markers to periodontal disease and jaw bone morphology in elderly Japanese subjects

The purpose of this study was to evaluate the relation of bone turnover markers such as bone formation and resorption to periodontal disease and jaw bone morphology in elderly Japanese subjects. We selected 148 subjects for participation in this study. All subjects were aged 77 years. The periodontal examination included the assessment of clinical attachment level (CAL). Biochemical parameters of bone turnover measured included urinary deoxypyridinoline, serum osteocalcin (S-OC), and serum bone-specific alkaline phosphatase. In addition, to evaluate the jawbone, we used the mandibular inferior cortex classification (MIC). Serum osteocalcin had significantly higher (males: P = 0.038, females: P = 0.041) tendency for MIC Class (ANOVA). Multiple linear regression results showed that the number of remaining teeth and S-OC were negatively associated with the percentage of sites with > or =6 mm CAL (R(2) = 0.322, P < 0.001). Coefficients and betas were -0.71, -0.46 (P < 0.001) and -1.11, -0.28 (P = 0.002), respectively. In conclusion, this study suggests that there is a significant relation of bone turnover markers to periodontal disease and jaw bone morphology in elderly Japanese subjects.

Detection of post-menopausal women with low bone mineral density and elevated biochemical markers of bone turnover by panoramic radiographs

The detection of an eroded mandibular cortex on panoramic radiographs and questionnaire-based screening tools show similar diagnostic efficacies for identifying osteoporosis in post-menopausal women. We evaluated whether both tools also have similar diagnostic performances in identifying women with osteoporosis and elevated biochemical markers of bone turnover who have a high risk of fracture. Urinary N-telopeptide cross-links of type I collagen (NTx) (corrected for creatinine) and serum levels of total non-bone-specific alkaline phosphatase (ALP) were measured in 99 post-menopausal women aged 44-70 years (mean +/- standard deviation (SD), 54.6 +/- 5.2 years) who underwent bone mineral density (BMD) assessment and panoramic radiography. BMD was measured at the lumbar spine and femoral neck using dual energy X-ray absorptiometry. The Female Osteoporosis Self-assessment Tool for Asia (FOSTA), which is based on age and weight, was used as the questionnaire-based screening tool. Osteoporosis was defined as a BMD T-score of -2.5 or less at either the lumbar spine or the femoral neck. Urinary NTx and serum ALP were significantly associated with cortical erosion, but not with the FOSTA. The areas under the receiver operating characteristics (ROC) curve for identifying participants with osteoporosis were 0.784 for FOSTA and 0.827 for the detection of cortical erosion, and for identifying participants with osteoporosis and elevated urinary NTx they were 0.700 for FOSTA and 0.807 for the detection of cortical erosion. Our results suggest that panoramic radiography is superior to questionnaire-based screening for identifying women who are at high risk of fracture.

Periodontal tissue engineering by transplantation of multilayered sheets of phenotypically modified gingival fibroblasts

In periodontal tissue engineering, the sourcing of most of the relevant cells is limited by poor accessibility, whereas the use of readily available gingival fibroblasts is hampered because of their inhibitory effects on bone formation. To address the latter drawback, we developed a new graft composed of fibronectin (FN) matrix-based multilayered cell sheets of human gingival fibroblasts modified to express alkaline phosphatase (ALP). This study was undertaken to investigate the effects of this graft, called the FN-ALP transplant, on the healing of periodontal defects in a rat model. The FN-ALP transplants were grafted into periodontal fenestration bone defects in immunosuppressed rats. The process of periodontal healing was examined by histology, histomorphometry and immunohistochemistry. Grafted cells were tracked by immunostaining with human-specific antibodies. Control groups included non-transplanted empty defects and defects to which cell sheets without ALP induction had been grafted. After implantation, the FN-ALP transplants healed alveolar bone defects by intramembranous ossification, with formation of cementum and periodontal ligament. Moreover, FN-ALP transplants increased new bone formation, by endochondral ossification, on the mandibular cortex adjacent to the defect. Grafted fibroblasts were located near host osteoblasts and chondrocyte precursor cells early in the ossification process but were undetectable on and in newly formed bone and cartilage. These results indicate that the FN-ALP transplants support alveolar bone regeneration within the defect and augment bone formation outside the defect through the recruitment of host osteo/chondrogenic cells, suggesting their potential for periodontal tissue engineering applications.

Morphologic Study of Mandibular Outer Cortex Osteotomy

The purpose of this study was to illustrate the morphologic changes of the mandible after outer cortex osteotomy. Ten patients had undergone mandibular outer cortex osteotomy. By using the true-up and dissection techniques based on three-dimensional spiral computed tomography, variables of effect and bone regeneration were evaluated 6 months postoperatively. Concavity could be seen in the area from which the mandibular outer cortex had been removed 6 months postoperatively, especially at the external oblique line region. The average cup depth was 3.64 +/- 1.67 mm postoperatively. Diminution of bone volume was 1.7 +/- 0.5 percent for the entire mandible and 55 +/- 9 percent for the local area 6 months postoperatively. Bone regeneration could be seen in the area from which the mandibular outer cortex had been removed. Compared with immediately postoperatively, the ratio of neoformative bone was 84.6 +/- 7.3 percent 6 months postoperatively. The main region of bone regeneration was the mandibular angle. Mandibular outer cortex osteotomy is an effective technique for reducing the width of the lower face. Masseter muscular movement should be restricted postoperatively to prevent hyperostosis at the angle area.