• The Journal of Advanced Prosthodontics
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• 제7권1호
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• pp.51-55
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• 2015

PURPOSE. Bone density at implant placement site is a key factor to obtain the primary stability of the fixture, which, in turn, is a prognostic factor for osseointegration and long-term success of an implant supported rehabilitation. Recently, an implant motor with a bone density measurement probe has been introduced. The aim of the present study was to test the objectiveness of the bone densities registered by the implant motor regardless of the operator performing them. MATERIALS AND METHODS. A total of 3704 bone density measurements, performed by means of the implant motor, were registered by 39 operators at different implant sites during routine activity. Bone density measurements were grouped according to their distribution across the jaws. Specifically, four different areas were distinguished: a pre-antral (between teeth from first right maxillary premolar to first left maxillary premolar) and a sub-antral (more distally) zone in the maxilla, and an interforaminal (between and including teeth from first left mandibular premolar to first right mandibular premolar) and a retroforaminal (more distally) zone in the lower one. A statistical comparison was performed to check the inter-operators variability of the collected data. RESULTS. The device produced consistent and operator-independent bone density values at each tooth position, showing a reliable bone-density measurement. CONCLUSION. The implant motor demonstrated to be a helpful tool to properly plan implant placement and loading irrespective of the operator using it.

• 한국임상수의학회지
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• 제20권3호
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• pp.351-356
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• 2003

The aim of this experiment was to study the calcium sulfate on early bone consolidation in distraction osteogenesis in the canine mandible. Twelve dogs were used and divided into control group (group A, 4 heads), sodium hyaluronate injection group (group B, 4 heads), mixture of calcium sulfate and sodium hyaluronate injection group (group C, 4 heads). Each group were subdivided into 3 weeks testing group (totally 6 heads) and 5 weeks testing group (totally 6 heads). Mandibular distraction was started at the 5th day after the mandibular osteotomy and continued for 10 days by 1 mm a day. After the distraction on the 10th day of mandibular distraction, 0.5 m1 saline in group A, 0.5 m1 sodium hyaluronate in group B, and 0.5 ml mixture of calcium sulfate and sodium hyaluronate in group C were each injected in mandibular distraction lesion. And X-ray examination, bone mineral density, and histopathological findings were examined. The radiological findings were the most radiopaque in group C, and the most radiolucent in group A in both 3 and 5 week testing group. The level of bone mineral density was also the highest in group C, and the lowest in group C in both 3 and 5 week testing group. The histopathological findings of new bone formation were the most remarkable in group C in both 3 and 5 week testing group. New bone formation of group A was not present in both 3 and 5 week testing group. In conclusion, calcium sulfate is a kind of material that can stimulate early bone formation and can shorten the duration of bone consolidation. And it can be effective in clinical usage.

• Imaging Science in Dentistry
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• 제47권2호
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• pp.87-92
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• 2017

Purpose: The aim of this study was to determine whether the panoramic mandibular index (PMI) is useful for assessing bone mineral density. We also analyzed the potential correlations between PMI parameters and patient age. Materials and Methods: Four observers measured the PMI of both sides of the mental foramen using a picture archiving and communication system and images in the Digital Imaging and Communications in Medicine format. They studied 300 panoramic radiographic images of patients belonging to the following age groups: 40-49 years, 50-59 years, 60-69 years, 70-79 years, and 80-89 years. The observers were allowed to zoom in or out and to adjust the contrast of the images. Further, they were instructed to record the reasons for any measurements that could not be made. Then, we conducted a reliability analysis of the measured PMI and assessed the correlations between different patient age groups and the 3 parameters used for determining the PMI from the available data. Results: Among the 600 data items collected, 23 items were considered unmeasurable by at least 1 observer for the following 4 reasons: postoperative state, lesion, unidentified mental foramen, and alveolar bone loss. The intraobserver reproducibility of the measurable data was 0.611-0.752. The mandibular cortical width (MCW) decreased significantly as patient age increased. Conclusion: PMI had limited usability when the margin of the mental foramen was not clear. In contrast, MCW, a parameter used for determining the PMI, had fewer drawbacks than the PMI with respect to bone mineral density measurements and exhibited a significant correlation with patient age.

• Imaging Science in Dentistry
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• 제52권1호
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• pp.53-60
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• 2022

Purpose: The aim of this study was to compare the fractal dimension (FD) measured at 2 bone sites (second cervical vertebra and mandible) on cone-beam computed tomography (CBCT). The research question was whether FD could serve as an accessory tool to refer postmenopausal women for densitometric analysis. Therefore, the reliability and accuracy of FD were evaluated. Materials and Methods: In total, 103 postmenopausal women were evaluated, of whom 52 had normal bone mineral density and 51 had osteoporosis, according to dual X-ray absorptiometry of the lumbar spine and hip. On the CBCT scans, 2 regions of interest were selected for FD analysis: 1 at the second cervical vertebra and 1 located at the mandible. The correlations between both measurements, intra- and inter-observer agreement, and the accuracy of the measurements were calculated. A P value less than 0.05 was considered to indicate statistical significance for all tests. Results: The mean FD values were significantly lower at the mandibular region of interest in osteoporotic patients than in individuals with normal bone mineral density. The areas under the curve were 0.644 (P=0.008) and 0.531 (P=0.720) for the mandibular and vertebral sites, respectively. Conclusion: FD at the vertebral site could not be used as an adjuvant tool to refer women for osteoporosis investigation. Although FD differed between women with normal BMD and osteoporosis at the mandibular site, it demonstrated low accuracy and reliability.

• Imaging Science in Dentistry
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• 제31권2호
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• pp.67-71
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• 2001

Purpose: To assess the possibility of using panoramic indices as an indicator of jaw osteoporosis. Methods: Mandibular cortical width (MCW), degree of mandibular alveolar bone resorption (ABR) and morphology of mandibular inferior cortex (MIC) on panoramic radiograph were used as panoramic indices. These panoramic indices were compared with bone mineral density (BMD) of lumbar (L1-L4) and femoral neck measured by dual energy X-ray absorptiometry. We also compared MCW and ABR of young men with those of postmenopausal women. Results : There was a significant correlation between ABR and BMD of lumbar and femoral neck. And also significant correlation between MIC and BMD of lumbar and femoral neck. ANOVA test of BMD of lumbar and femoral neck showed significant differences according to morphologic classification of inferior cortex. There was significant difference in MCW and ABR between young men and postmenopausal women. Conclusion: Our results suggested that ABR and MIC on panoramic radiograph could be reliable in screening of osteoporosis.

• Imaging Science in Dentistry
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• 제48권4호
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• pp.283-287
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• 2018

Craniometaphyseal dysplasia (CMD) is a rare hereditary disorder characterized by hyperostosis of the craniofacial bones and flared metaphyses of the long bones. Although some reports have described the dentomaxillofacial characteristics of CMD, including increased density of the jaw, malocclusion, and delayed eruption of the permanent teeth, only a few studies have reported the distinct imaging features of CMD on panoramic radiography. This report presents 2 cases of confirmed CMD patients with an emphasis on panoramic imaging features. The patients' images revealed hyperostosis and sclerosis of the maxilla and mandibular alveolar bone, but there was no change in the mandibular basal bone. In both cases, the mandibular condyle heads exhibited a short clubbed shape with hyperplasia of the coronoid process. For patients without clear otorhinolaryngological symptoms, common radiologic features of CMD could be visualized by routinely-taken panoramic radiographs, and further medical examinations and treatment can be recommended.

• 치과방사선
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• 제21권2호
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• pp.203-220
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• 1991

The purpose of this study was to investigate the changes of morphology and structure of bone tissue, caused by administration of high-dose hydrocortisone, elcatonin and cyclophosphamide. In order to carry out experiment, 60 four-week old Sprague-Dawley strain rats weighing about 107 gms were selected and divided into experimental group and control group. The experimental group was subdivided into three groups, assigned fifteen rats for each group, by the different drugs administered. Each experimental group was then categorized as follows: hydrocortisone 30㎎/㎏ b.w. with daily subcutaneous injection, elcatonin 20U/㎏ b.w. with daily subcutaneous injection, and cyclophosphamide 100㎎/㎏ b.w. with a single intraperitoneal injection. Fifteen rats were injected daily with 5㎖/㎏ b.w. of normal saline solution subcutaneously in control group. Rats in control group and experimental group were serially sacrificed on the 6th, the 15th and the 22nd day after injection of normal saline, hydrocortisone, elcatonin and cyclophosphamide, respectively. Being sacrificed, both sides of mandibular condyles were removed and fixed with 10% neutral formaline. The one side of mandibular condyles was radiographed with soft X-ray apparatus. Thereafter, the obtained radiographs were observed, and the bone density of condylar head and condylar neck regions was measured by use of transferring video-based digital radiograph. The other side was further decalcified and embedded in paraffin as usual manner, then sectioned and stained with hematoxylin and eosin, observed by light microscope. The obtained results were as follows: 1. Sclerotic changes with regularly increased trabecular pattern were seen throughout experimental periods in hydrocortisone group. Increased the number of trabecular pattern with irregularity and periodic striation on the periphery of condylar head region were appeared with lapse of time in elcatonin group. In cyclophosphamide group, irregular trabecular pattern and stippled radiopacities on mandibular condyle were observed with lapse of time. 2. The bone density of condylar head region was increased in hydrocortisone group, decreased in elcatonin group, and tended to be decreased in cyclophosphamide group, compared with that of control group according to the experimental periods. 3. The bone density of condylar neck region tended to be rather increased in hydrocortisone group, elcatonin group and cyclophosphamide group, depending on the experimental periods. 4. In microscopic studies, there were irregular trabecular bonds and osteoblastic activity in hydrocortisone group and elcatonin group throughout experimental periods, degenerative cartilage and trabecular bones in the 6th day and densely calcified trabecular bones in the 22nd day in cyclophosphamide group.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제37권6호
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• pp.496-504
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• 2011

Introduction: This study compared the alveolar bone density of the mandible according to gender, age and position using Cone-beam computed tomography (CT). Materials and Methods: The maxillofacial CT scan data was obtained from 60 Korean patients. In addition, the alveloar bone density of 5 males and 5 females with normal occlusion aged from 10 to 70 years was measured at the buccal cortical bone, cancellous bone and lingual cortical bone, as well as at the position of the incisors, canines, premolars and molars. Results: The age-specific mean bone density was highest in patients in their third decade. The buccal cortical bone of the molars showed the highest bone density. Males in their fifties and sixties had a higher bone density in the cancellous bone in the region of the premolars and the buccal cortical bone of the molars, respectively, than females but there was no significant difference between males and females in the other parts. The cancellous bone density was highest in those in their twenties and thirties, and tended to decline up to their seventh decade. Conclusion: These results revealed a significantly different bone density according to gender, age and position in the Korean population. In addition, it is possible to predict the bone density based on these results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제44권3호
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• pp.128-135
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• 2018

Objectives: The role of alloplastic materials in maxillofacial reconstruction is still controversial. Determining the utility of porous, high-density, polyethylene implants as a highly stable and flexible, porous alloplast, with properties such as rapid vascularization and tissue ingrowth, is crucial in cases of maxillofacial deformities and aesthetic surgery. Materials and Methods: Thirty high-density porous polyethylene implants were implanted in 16 patients that had been referred to a private office over a three-year period. These implants were used for correcting congenital deformities, posttraumatic defects and improving the aesthetic in nasal, paranasal, malar, chin, mandibular angle, body and orbital areas. Results: The outcomes of the cases in this study showed good aesthetic and functional results. The majority of patients had no signs of discomfort, rejection or exposure. Two implants suffered complications: a complicated malar implant was managed by antibiotic therapy, and an infected mandibular angle implant was removed despite antibiotic therapy. Conclusion: Based on the results, the Medpor implant seems to be an excellent biomaterial for correcting various facial deformities. Advantages include its versatility and relatively ideal pore size that allows for excellent soft tissue ingrowth and coverage. It is strong, flexible and easy to shape.

• Imaging Science in Dentistry
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• 제41권3호
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• pp.101-106
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• 2011

Purpose : This study evaluated the potential use of the computed tomography indices (CTI) on cone beam CT (CBCT) images for an assessment of the bone mineral density (BMD) in postmenopausal osteoporotic women. Materials and Methods : Twenty-one postmenopausal osteoporotic women and 21 postmenopausal healthy women were enrolled as the subjects. The BMD of the lumbar vertebrae and femur were calculated by dual energy X-ray absorptiometry (DXA) using a DXA scanner. The CBCT images were obtained from the unilateral mental foramen region using a PSR-$9000N^{TM}$ Dental CT system. The axial, sagittal, and coronal images were reconstructed from the block images using $OnDemend3D^{TM}$. The new term "CTI" on CBCT images was proposed. The relationship between the CT measurements and BMDs were assessed and the intra-observer agreement was determined. Results : There were significant differences between the normal and osteoporotic groups in the computed tomography mandibular index superior (CTI(S)), computed tomography mandibular index inferior (CTI(I)), and computed tomography cortical index (CTCI). On the other hand, there was no difference between the groups in the computed tomography mental index (CTMI: inferior cortical width). Conclusion : CTI(S), CTI(I), and CTCI on the CBCT images can be used to assess the osteoporotic women.