儿童下颌骨骨密度的定量CT测量研究

目的 对71名10～16岁儿童的下颌骨骨密度进行定量CT(QCT)测量,探讨骨密度的变化情况.方法 对每名儿童的左侧下颌角、颏中部和右侧下颌角分别进行QCT扫描测量,并按照年龄和性别进行分析.结果 10～12岁儿童左侧下颌角、颏中部、右侧下颌角骨密度平均值分别为44.29、89.70、54.31 mg/dL;13～16岁儿童左侧下颌角、颏中部、右侧下颌角骨密度平均值分别为63.85、122.47、70.23 mg/dL.结论 男性儿童10～12岁组与13～16岁组下颌骨骨密度值随年龄的增加而明显增高,但左右两侧下颌角及颏中部骨密度值有较大差异,男女之间骨密度值也有很大的差异.     

我国北方成年人下颌骨骨密度的测量研究

目的 研究健康人下颌骨与全身骨密度的相关性.方法 选择中国北方健康志愿者221名,分别将不同性别的志愿者按年龄分为6组,即≥20岁(男21人、女23人)、≥30岁(男20人、女21人)、≥40岁(男21人、女22人)、≥50岁(男20人、女21人)、≥60岁(男16人、女15人)、≥170岁(男11人、女10人).从每人下颌骨颏部及双侧下颌角各选10个感兴趣区,用双能X线骨密度仪测量骨密度值,同时测量腰椎(L2-L4);并行统计学分析.结果 该人群的下颌骨颏部的骨密度值为(1.310 9±0.035 5)g/cm2,左下颌角的骨密度值(1.048 9±0.013 7)g/cm2,右下颌角的骨密度值(1.054 7±0.014 1)g/cm2,腰椎(L2-L4)的骨密度值(1.1211±0.0172)g/cm2.男女之间下颌角、腰椎的骨密度比较,差异有统计学意义(t(左)=2.017 5,t(右)=2.446 9,P<0.05).50岁以后下颌角、腰椎的骨密度明显减低.结论 下颌骨与腰椎的骨密度密切相关,下颌骨可以作为测量全身骨密度的一个敏感部位进行骨质疏松的预测.     

我国北方成年人下颌骨骨密度的测量研究

Objective To measure the bone mineral density(BMD)of mandible and investigate the relationship between mandible and the whole body skeleton BMD.Methods Healthy volunteers were recruited in north China,which were divided into 6 groups by age:≥20,≥30,≥40,≥50,≥60 and ≥70 years older,10 male and 10 female in each group.Dual-energy X-ray absoptiometery(DXA)was used to measure the BMD of the lumbar spine,the mentum of mandible and the mandibular angle.The results were analyzed statistically.Results The mineral density(MD )of the mentum was(1.310 9 ±0.035 5)g/cm2,the left mandibular angle(1.048 9 ± 0.013 7)g/cm2,the right mandibular angle (1.0547 ±0.014 1)g/cm2,the lumbar spine(L2-L4)(1.121 1±0.017 2)g/cm2.There was a significant difference in mandibular angle and lumbar MD between men and women(P＜0.05).The MD of mandibular angle and lumbar spine decreased significantly after 50 years of age.Conclusions The normal BMD of the mandibular mentum,mandibular angles and lumbar spine is obtained.The BMD of the mandibular angles is closely related to that of the lumbar spine.Mandible can be an appropriate measurement site in the evaluation of skeleton BMD status for the forecast of osteoporosis.     

我国北方成年人下颌骨骨密度的测量研究

Objective To measure the bone mineral density(BMD)of mandible and investigate the relationship between mandible and the whole body skeleton BMD.Methods Healthy volunteers were recruited in north China,which were divided into 6 groups by age:≥20,≥30,≥40,≥50,≥60 and ≥70 years older,10 male and 10 female in each group.Dual-energy X-ray absoptiometery(DXA)was used to measure the BMD of the lumbar spine,the mentum of mandible and the mandibular angle.The results were analyzed statistically.Results The mineral density(MD )of the mentum was(1.310 9 ±0.035 5)g/cm2,the left mandibular angle(1.048 9 ± 0.013 7)g/cm2,the right mandibular angle (1.0547 ±0.014 1)g/cm2,the lumbar spine(L2-L4)(1.121 1±0.017 2)g/cm2.There was a significant difference in mandibular angle and lumbar MD between men and women(P＜0.05).The MD of mandibular angle and lumbar spine decreased significantly after 50 years of age.Conclusions The normal BMD of the mandibular mentum,mandibular angles and lumbar spine is obtained.The BMD of the mandibular angles is closely related to that of the lumbar spine.Mandible can be an appropriate measurement site in the evaluation of skeleton BMD status for the forecast of osteoporosis.     

我国北方成年人下颌骨骨密度的测量研究

Objective To measure the bone mineral density(BMD)of mandible and investigate the relationship between mandible and the whole body skeleton BMD.Methods Healthy volunteers were recruited in north China,which were divided into 6 groups by age:≥20,≥30,≥40,≥50,≥60 and ≥70 years older,10 male and 10 female in each group.Dual-energy X-ray absoptiometery(DXA)was used to measure the BMD of the lumbar spine,the mentum of mandible and the mandibular angle.The results were analyzed statistically.Results The mineral density(MD )of the mentum was(1.310 9 ±0.035 5)g/cm2,the left mandibular angle(1.048 9 ± 0.013 7)g/cm2,the right mandibular angle (1.0547 ±0.014 1)g/cm2,the lumbar spine(L2-L4)(1.121 1±0.017 2)g/cm2.There was a significant difference in mandibular angle and lumbar MD between men and women(P＜0.05).The MD of mandibular angle and lumbar spine decreased significantly after 50 years of age.Conclusions The normal BMD of the mandibular mentum,mandibular angles and lumbar spine is obtained.The BMD of the mandibular angles is closely related to that of the lumbar spine.Mandible can be an appropriate measurement site in the evaluation of skeleton BMD status for the forecast of osteoporosis.     

我国北方成年人下颌骨骨密度的测量研究

Objective To measure the bone mineral density(BMD)of mandible and investigate the relationship between mandible and the whole body skeleton BMD.Methods Healthy volunteers were recruited in north China,which were divided into 6 groups by age:≥20,≥30,≥40,≥50,≥60 and ≥70 years older,10 male and 10 female in each group.Dual-energy X-ray absoptiometery(DXA)was used to measure the BMD of the lumbar spine,the mentum of mandible and the mandibular angle.The results were analyzed statistically.Results The mineral density(MD )of the mentum was(1.310 9 ±0.035 5)g/cm2,the left mandibular angle(1.048 9 ± 0.013 7)g/cm2,the right mandibular angle (1.0547 ±0.014 1)g/cm2,the lumbar spine(L2-L4)(1.121 1±0.017 2)g/cm2.There was a significant difference in mandibular angle and lumbar MD between men and women(P＜0.05).The MD of mandibular angle and lumbar spine decreased significantly after 50 years of age.Conclusions The normal BMD of the mandibular mentum,mandibular angles and lumbar spine is obtained.The BMD of the mandibular angles is closely related to that of the lumbar spine.Mandible can be an appropriate measurement site in the evaluation of skeleton BMD status for the forecast of osteoporosis.     

我国北方成年人下颌骨骨密度的测量研究

Objective To measure the bone mineral density(BMD)of mandible and investigate the relationship between mandible and the whole body skeleton BMD.Methods Healthy volunteers were recruited in north China,which were divided into 6 groups by age:≥20,≥30,≥40,≥50,≥60 and ≥70 years older,10 male and 10 female in each group.Dual-energy X-ray absoptiometery(DXA)was used to measure the BMD of the lumbar spine,the mentum of mandible and the mandibular angle.The results were analyzed statistically.Results The mineral density(MD )of the mentum was(1.310 9 ±0.035 5)g/cm2,the left mandibular angle(1.048 9 ± 0.013 7)g/cm2,the right mandibular angle (1.0547 ±0.014 1)g/cm2,the lumbar spine(L2-L4)(1.121 1±0.017 2)g/cm2.There was a significant difference in mandibular angle and lumbar MD between men and women(P＜0.05).The MD of mandibular angle and lumbar spine decreased significantly after 50 years of age.Conclusions The normal BMD of the mandibular mentum,mandibular angles and lumbar spine is obtained.The BMD of the mandibular angles is closely related to that of the lumbar spine.Mandible can be an appropriate measurement site in the evaluation of skeleton BMD status for the forecast of osteoporosis.     

我国北方成年人下颌骨骨密度的测量研究

Objective To measure the bone mineral density(BMD)of mandible and investigate the relationship between mandible and the whole body skeleton BMD.Methods Healthy volunteers were recruited in north China,which were divided into 6 groups by age:≥20,≥30,≥40,≥50,≥60 and ≥70 years older,10 male and 10 female in each group.Dual-energy X-ray absoptiometery(DXA)was used to measure the BMD of the lumbar spine,the mentum of mandible and the mandibular angle.The results were analyzed statistically.Results The mineral density(MD )of the mentum was(1.310 9 ±0.035 5)g/cm2,the left mandibular angle(1.048 9 ± 0.013 7)g/cm2,the right mandibular angle (1.0547 ±0.014 1)g/cm2,the lumbar spine(L2-L4)(1.121 1±0.017 2)g/cm2.There was a significant difference in mandibular angle and lumbar MD between men and women(P＜0.05).The MD of mandibular angle and lumbar spine decreased significantly after 50 years of age.Conclusions The normal BMD of the mandibular mentum,mandibular angles and lumbar spine is obtained.The BMD of the mandibular angles is closely related to that of the lumbar spine.Mandible can be an appropriate measurement site in the evaluation of skeleton BMD status for the forecast of osteoporosis.     

我国北方成年人下颌骨骨密度的测量研究

Objective To measure the bone mineral density(BMD)of mandible and investigate the relationship between mandible and the whole body skeleton BMD.Methods Healthy volunteers were recruited in north China,which were divided into 6 groups by age:≥20,≥30,≥40,≥50,≥60 and ≥70 years older,10 male and 10 female in each group.Dual-energy X-ray absoptiometery(DXA)was used to measure the BMD of the lumbar spine,the mentum of mandible and the mandibular angle.The results were analyzed statistically.Results The mineral density(MD )of the mentum was(1.310 9 ±0.035 5)g/cm2,the left mandibular angle(1.048 9 ± 0.013 7)g/cm2,the right mandibular angle (1.0547 ±0.014 1)g/cm2,the lumbar spine(L2-L4)(1.121 1±0.017 2)g/cm2.There was a significant difference in mandibular angle and lumbar MD between men and women(P＜0.05).The MD of mandibular angle and lumbar spine decreased significantly after 50 years of age.Conclusions The normal BMD of the mandibular mentum,mandibular angles and lumbar spine is obtained.The BMD of the mandibular angles is closely related to that of the lumbar spine.Mandible can be an appropriate measurement site in the evaluation of skeleton BMD status for the forecast of osteoporosis.     

我国北方成年人下颌骨骨密度的测量研究

Objective To measure the bone mineral density(BMD)of mandible and investigate the relationship between mandible and the whole body skeleton BMD.Methods Healthy volunteers were recruited in north China,which were divided into 6 groups by age:≥20,≥30,≥40,≥50,≥60 and ≥70 years older,10 male and 10 female in each group.Dual-energy X-ray absoptiometery(DXA)was used to measure the BMD of the lumbar spine,the mentum of mandible and the mandibular angle.The results were analyzed statistically.Results The mineral density(MD )of the mentum was(1.310 9 ±0.035 5)g/cm2,the left mandibular angle(1.048 9 ± 0.013 7)g/cm2,the right mandibular angle (1.0547 ±0.014 1)g/cm2,the lumbar spine(L2-L4)(1.121 1±0.017 2)g/cm2.There was a significant difference in mandibular angle and lumbar MD between men and women(P＜0.05).The MD of mandibular angle and lumbar spine decreased significantly after 50 years of age.Conclusions The normal BMD of the mandibular mentum,mandibular angles and lumbar spine is obtained.The BMD of the mandibular angles is closely related to that of the lumbar spine.Mandible can be an appropriate measurement site in the evaluation of skeleton BMD status for the forecast of osteoporosis.     

Bone mineral density of the mandible in ovariectomized rats: analyses using dual energy X-ray absorptiometry and peripheral quantitative computed tomography

INTRODUCTION: Although previous studies have shown that maxillary molar extraction in ovariectomized (OVX) animals causes mandibular loss of bone, it is still questionable as to whether estrogen deficiency affects mandibles with functional occlusion. MATERIALS AND METHODS: To answer this question, 13-week-old female Sprague-Dawley rats were bilaterally OVX or sham-operated. After 109 days, the bone mineral density (BMD) of the femurs and mandibles was measured using dual-energy X-ray absorptiometry (DEXA) and peripheral quantitative computed tomography (pQCT). RESULTS: In DEXA analysis, although the BMD of the total mandible of the OVX rats was similar to that of the sham-operated rats, the BMD of the condylar region in the OVX rats had decreased by 12.5%. In pQCT analysis, decrease in trabecular BMD of the mandibular bone was detectable but low in the molar region (maximal 13%), whereas no difference was seen in cortical BMD. In the femurs, the trabecular bone prominently decreased in OVX rats (30% decrease in pQCT analysis) as previously reported. CONCLUSION: This study revealed regional differences in the mandibular bone decrease in OVX rats. Although the mechanism of low susceptibility of the mandible to estrogen-deficient conditions remains unknown, it is likely that mechanical stress derived from functional occlusion is preventing bone loss in this pathological condition. Furthermore, this study demonstrated the advantage of pQCT in analyzing rat mandibular bone.     

Bone density in human dentate and edentulous mandibles using computed tomography

Mandibular bone density, vertebral density and resorption of the edentulous ridge were correlated in a group of 17 partially edentulous subjects. Bone density was quantified by Quantitative Computerized Tomography; resorption was evaluated on panoramic radiographs. Mean bone density in dentate areas was significantly higher than that in edentulous areas; mandibular bone density was not found to relate significantly to vertebral bone density, nor to ridge resorption. In programming osseointegrated implants in the partially edentulous mandible, CT may give a more accurate evaluation of trabecular bone. However, further studies are necessary to clarify its clinical utility.     

Quantitative computed tomography bone mineral density measurements in irradiated and non-irradiated minipig alveolar bone: an experimental study

Objective: The objective of this study was to analyse the effect of irradiation on bone mineral density (BMD). Materials and methods: All maxillary and mandibular pre‐molars and molars of six minipigs were extracted. After a 3‐month healing period, the maxilla and mandibles of three minipigs received three irradiation exposures at a total dose of 24 Gy. At 3 months after irradiation, quantitative computed tomography (QCT) was performed. As a reference, a calibration bone phantom with pre‐determined BMD was attached to the head of the minipigs. The QCT data were imported into a software program to calculate the BMD of the alveolar bone and the calibration bone phantom. In order to compare BMD values of individual minipigs, the so‐called bone mineral density quotient (BMDQ) was created, dividing the BMD value of the alveolar bone by the BMD value of the calibration bone phantom. Results: Mean BMDQ values appeared to be higher in irradiated than in non‐irradiated minipigs. However, the difference was not significant. In both irradiated and non‐irradiated minipigs, the average mandibular BMDQ values were statistically significantly higher than the average maxillary BMDQ values (P=0.003). The P‐values of the Student t‐test, determining the irradiation effect, were 0.11 for maxillary, 0.14 for mandibular, and 0.07 for overall peri‐implant BMDQ. P‐values of the non‐parametric Mann–Whitney test were all 0.05. Conclusion: It could be concluded that, 3 months after irradiation, the BMD of irradiated alveolar minipig bone was increased, when compared with non‐irradiated alveolar minipig bone. However, the increase was not statistically significant.     

Prospective study to estimate mandibular cancellous bone density using large‐volume cone‐beam computed tomography

Objective: Because pixel or voxel values obtained from cone‐beam computed tomography (CBCT) images are not absolute values, the bone density cannot be evaluated. Hence, the regression line between voxel values of CBCT and the bone mineral density (BMDs) of multislice CT (MSCT) was prospectively evaluated to investigate the mandibular cancellous bone density. Also, the usefulness of a reference bone block was evaluated on assessing a low mandibular bone density. Materials and methods: A total of 15 (two males and 13 females) patients who had undergone postoperative imaging for mandibular dental implant treatment with a bone graft using CBCT and MSCT were enrolled in this investigation. Voxel values of region of interests in CBCT were transformed to BMDs using a regression line from a previous study, and differences between BMDs obtained using CBCT and MSCT were calculated. Also, the voxel values of CBCT at the selected sites, in which the bone density was measured between 100 and 300 mg/cm³ of hydroxyapatite (HA) in MSCT, were assessed regarding whether they were higher or lower than the BMD of the reference bone block. Results: The mean overall difference was 38 mg/cm³ of HA. Thirty‐eight of the 45 sites (84%) were accurately assessed using the reference bone block. Conclusion: The usefulness of a regression line for BMD estimation in CBCT was prospectively confirmed in mandibular cancellous bone. Also, the reference bone block was useful to assess the low bone density of mandibular cancellous bone on CBCT with a large volume. To cite this article:
Naitoh M, Hirukawa A, Katsumata A, Ariji E. Prospective study to estimate mandibular cancellous bone density using large‐volume cone‐beam computed tomography.
Clin. Oral Impl. Res. xx , 2010; 1309–1313.
doi: 10.1111/j.1600‐0501.2010.01950.x     

Evaluation of voxel values in mandibular cancellous bone: relationship between cone-beam computed tomography and multislice helical computed tomography

Objective: Measurements of bone density in designed sites are important in presurgical imaging for dental implant treatment. However, the pixel or voxel values obtained from cone-beam computed tomography (CT) images are not absolute values. Hence, the relationship between voxel values obtained from cone-beam CT with a limited-volume exposure field and a flat panel detector and bone mineral densities (BMDs) obtained from multislice CT was evaluated in the mandible.
Material and methods: A total of 16 (four males and 12 females) patients who had undergone imaging for mandibular dental implant treatment using cone-beam CT with Alphard VEGA and multislice CT were enrolled in this investigation.
Cross-sectional images of cone-beam and multislice CT were reconstructed, and values of regions of interest (ROIs) in images were calculated.
Results: A high-level correlation between voxel values of cone-beam CT and BMDs of multislice CT was observed ( r =0.965).
Conclusion: It was suggested that voxel values of mandibular cancellous bone in cone-beam CT could be used to estimate bone density.     

Trabecular bone mineral density of mandible and alveolar height in postmenopausal women

Mineral density of the trabecular bone of the mandible was determined by single-energy QCT (quantitative computed tomography) for 74 totally or nearly edentulous menopausal women. These results were compared with the bone mineral densities (BMD) of their lumbar area (L2–L4) and femoral collum, measured by dual-energy x-ray transmission, Lunar DPX. The remaining height of the residual ridge at the symphysis of the mandible was measured on computed tomography (CT) lateral projection view, and an index of the residual ridge status was introduced. To determine whether general osteoporosis status affects the remaining height of the residual ridges, we compared these values with all results for bone mineral density. The BMD of the lumbar area and that of the femoral collum correlated well with each other, but the BMD of the trabecular bone of the mandible did not correlate with either of the other two BMD measurements. Measurements of residual ridge height did not correlate with any BMD values. The effect of possible bone loss earlier in life is no longer apparent in mandibular height or trabecular BMD over 20 yr after tooth extractions.     

Cortical bone mineral density in the mandible and osteoporosis status in postmenopausal women

Mineral density of the cortical bone of the mandible was determined by single-energy QCT (quantitative computed tomography) for 77 menopausal women. Bone mineral densities (BMD) were measured in the buccal and lingual layers of the cortex, distally from the foramen mentale, on both sides of the mandible. All the women were edentulous in that region, and the alveolar processes were far resorbed. These results were compared with the BMD values of the femoral neck, lumbar spine, and trabecular portion of the mandible between the detected layers of cortex. The BMD of the buccal cortex correlated remarkably well with all values, except those of the trabecular portion. Of the women tested, the correlations were lowest in the least osteoporotic group. The values for the lingual cortex did not correlate with other variables as well as did those for the buccal cortex, but in the most osteoporotic part of the sample the lingual cortex values correlated significantly with the BMD of the trabecular portion. The BMD values for the buccal cortex were significantly higher than those for the lingual cortex.     

Evaluation by quantitative magnetic resonance imaging of trabecular bone quality in mandible and cervical vertebrae

Objective: The purpose of this study was to make a comparison between mandibular and cervical vertebral bone quality (BQ) using quantitative magnetic resonance imaging (MRI). Methods: The cervical MRI images included in this study belonged to 36 patients (23 women, 13 men; mean age 54 years) who had various clinical symptoms (e.g., headache, vertigo, imbalance). The mandible and cervical vertebrae BQ measurements were performed by the same investigator on these sections. Mandibular and cervical vertebral T2^* axial cross sections were performed following receipt of consent from each patient. T2^* relaxation time values were determined in the trabecular area. Results: The relationship between cervical vertebral and mandibular BQ was revealed by regression and correlation analysis. The correlation coefficient was r=0.04, r²=0.002, and P=0.818, which is not statistically significant. The relation between age and mandible BQ was very weak (r=0.001, r²=0.000001, and P=0.995), and the relation between age and cervical vertebrae BQ was correlated (r=?0.585, r²=0.342, and P<0.001). Conclusions: There is a low correlation between the BQ measurements of cervical vertebrae and the mandible. Precise mandibular BQ measurement does not provide information that correlates with BQ in the other sites of the skeleton. Although an age‐dependent decrease occurs in vertebral BQ, no significant alteration occurs in mandibular BQ. To cite this article:
Celenk P, Celenk C. Evaluation by quantitative magnetic resonance imaging of trabecular bone quality in mandible and cervical vertebrae.
Clin. Oral Impl. Res. 21 , 2010; 409–413.
doi: 10.1111/j.1600‐0501.2009.01869.x     

Relationship between the bone density estimated by cone-beam computed tomography and the primary stability of dental implants

Objectives: The aims of this study were to objectively assess bone quality with density values obtained by cone‐beam computed tomography (CBCT) and to determine the correlations between bone density and primary stability of dental implants. Material and methods: Eighteen Straumann implants were inserted into 18 fresh femoral heads of swine. The bone densities of implant recipient sites were preoperatively determined by the density value using CBCT. The maximum insertion torque value of each implant was recorded using a digital torque meter. Resonance frequency, which represented a quantitative unit called the implant stability quotient (ISQ), was measured using an Osstell^® Mentor immediately after the implant placement. Spearman's correlation coefficient was calculated to evaluate the correlations among density values, insertion torques, and ISQs at implant placement. Results: The density values ranged from 98 to 902. The mean density value, insertion torque, and ISQ were 591±226, 13.4±5.2 Ncm, and 67.1±8.1, respectively. Statistically significant correlations were found between the density values and insertion torque (r_s=0.796, P<0.001), density values and ISQ (r_s=0.529, P=0.024), and insertion torque and ISQ (r_s=0.758, P<0.001). Conclusions: The bone quality evaluated by specific CBCT showed a high correlation with the primary stability of the implants. Hence, preoperative density value estimations by CBCT may allow clinicians to predict implant stability. Whether the density values obtained by the CBCT device used in the present study could be applied to other devices requires further elucidation. To cite this article:
Isoda K, Ayukawa Y, Tsukiyama Y, Sogo M, Matsushita Y, Koyano K. Relationship between the bone density estimated by cone‐beam computed tomography and the primary stability of dental implants.
Clin. Oral Impl. Res. 23 , 2012; 832–836
doi: 10.1111/j.1600‐0501.2011.02203.x