There is plenty of literature on masticatory function and its impact on maxillofacial development. However, the influence of masticatory hypofunction on bone turnover in the alveolar bone has hardly been studied. This...There is plenty of literature on masticatory function and its impact on maxillofacial development. However, the influence of masticatory hypofunction on bone turnover in the alveolar bone has hardly been studied. This study aimed to clarify the influence of tooth loss and soft diet on the alveolar bone turnover during the growth period. Three-week-old Wistar rats were randomly divided into the following three groups: Hard diet group (rats raised on solid standard diet), Powder diet group (rats raised on powdered standard feed diet), and Extraction group (rats raised on powdered standard diet with maxillary molars extraction). BV, BMC, and BMD in the cancellous bone of M1 were measured using micro-CT analysis. To analyze the histological bone turnover, we prepared non-decalcified thin sections of alveolar cancellous bone when rats were 20 weeks old. On three-dimensional constructed images, the experimental groups (the Powder diet and Extraction groups) showed expansion of the medullary cavity of the interradicular septum of the first molar compared to controls (the Hard diet group). BV, BMC, and BMD were significantly lower in the experimental groups, with the difference from controls being greater in the Extraction group. On histomorphometric analysis, the bone mass parameters, bone formation parameters, and bone mineralization parameters were significantly lower in the experimental groups compared to controls. The bone resorption parameters were significantly higher in the experimental groups. From this study, we found that soft diet and tooth loss might worsen the bone microstructure, reduce osteogenesis, and promote bone resorption in alveolar bone.展开更多
Masticatory hypofunction and soft food affect the tooth rows, occlusion, and jawbone. This study aimed to clarify the influence of tooth loss and a soft diet <span>on morphology of the tooth root during the grow...Masticatory hypofunction and soft food affect the tooth rows, occlusion, and jawbone. This study aimed to clarify the influence of tooth loss and a soft diet <span>on morphology of the tooth root during the growth period. We divided</span><span> 3-week-</span><span>old Wistar rats into the following three groups: Hard diet group (rats raised on solid standard diet), Powder diet group (rats raised on powdered standard feed diet), and Extraction group (rats raised on powdered standard diet with maxillary molars extraction). Length, width, cross-sectional area, and volume </span><span>of the root of the mandibular M1 and M2 were measured using micro-CT</span><span> analysis. Non-decalcified thin-slice specimens of sagittal sections of the M1 were obtained at the age of 20 weeks, and the roots were observed. The root length of all roots in the Extraction group was significantly longer than that in the other groups. The root width and cross-sectional area at the apical side 1/4 of all roots in the Extraction group were significantly smaller than those in the other groups. The root volume of the M1 mesial root in the Extraction group was significantly smaller than that in the other groups.</span><span> </span><span>This study clarified that when masticatory stimulus in the immature teeth is reduced by the extraction of opposing teeth and a powder diet, the root length increases due </span><span>to the promotion of cellular cementum addition at the apex, and the root</span><span> width and cross-sectional area decrease due to the suppression of cellular cementum addition at the apical side 1/4 of the roots.</span>展开更多
The effects of childhood masticatory function loss and soft foods on the mandibular condyle have been the subject of much research. However, the corresponding bone turnover is not fully understood. The purpose of the ...The effects of childhood masticatory function loss and soft foods on the mandibular condyle have been the subject of much research. However, the corresponding bone turnover is not fully understood. The purpose of the present study was to clarify the effects of a lack of teeth and a soft food diet during the growth period on bone turnover in the mandibular condyle. We divided 3-week-old Wistar rats into the following three groups: 1) Extraction group: The maxillary molars were extracted at the age of 4 weeks, and animals were fed powdered standard feed. 2) Powder group: Animals were fed powdered standard feed without tooth extraction. 3) Control group: Animals were fed solid standard feed without tooth extraction. Non-decalcified thin-slice specimens of sagittal sections of the mandibular condyle were obtained at the age of 20 weeks for histological analysis. We used micro-CT analysis and bone histomorphometry to measure bone volume (BV), bone mineral content (BMC), bone mineral density (BMD), bone microstructure, bone resorption, and osteogenesis in the mandibular condyle, and we compared the results among groups. In the extraction and the powder groups, we found deformation and disruption of the arrangement of chondrocytes, coagulation of chondrocytes, and duplication of the tidemark in the cartilage. We also found an increase in multinuclear osteoclasts in the cancellous bone. We found a reduction in BV, BMC, and BMD in the extraction and powder groups compared to the control group, as well as a reduction of bone volume, a lowering of osteogenesis parameters, and an increase in bone resorption parameters in the secondary cancellous bone. These results suggest that a lack of teeth and a soft food diet during the growth period cause a decline in bone microstructure, a decrease in osteogenesis, and an increase in bone resorption.展开更多
文摘There is plenty of literature on masticatory function and its impact on maxillofacial development. However, the influence of masticatory hypofunction on bone turnover in the alveolar bone has hardly been studied. This study aimed to clarify the influence of tooth loss and soft diet on the alveolar bone turnover during the growth period. Three-week-old Wistar rats were randomly divided into the following three groups: Hard diet group (rats raised on solid standard diet), Powder diet group (rats raised on powdered standard feed diet), and Extraction group (rats raised on powdered standard diet with maxillary molars extraction). BV, BMC, and BMD in the cancellous bone of M1 were measured using micro-CT analysis. To analyze the histological bone turnover, we prepared non-decalcified thin sections of alveolar cancellous bone when rats were 20 weeks old. On three-dimensional constructed images, the experimental groups (the Powder diet and Extraction groups) showed expansion of the medullary cavity of the interradicular septum of the first molar compared to controls (the Hard diet group). BV, BMC, and BMD were significantly lower in the experimental groups, with the difference from controls being greater in the Extraction group. On histomorphometric analysis, the bone mass parameters, bone formation parameters, and bone mineralization parameters were significantly lower in the experimental groups compared to controls. The bone resorption parameters were significantly higher in the experimental groups. From this study, we found that soft diet and tooth loss might worsen the bone microstructure, reduce osteogenesis, and promote bone resorption in alveolar bone.
文摘Masticatory hypofunction and soft food affect the tooth rows, occlusion, and jawbone. This study aimed to clarify the influence of tooth loss and a soft diet <span>on morphology of the tooth root during the growth period. We divided</span><span> 3-week-</span><span>old Wistar rats into the following three groups: Hard diet group (rats raised on solid standard diet), Powder diet group (rats raised on powdered standard feed diet), and Extraction group (rats raised on powdered standard diet with maxillary molars extraction). Length, width, cross-sectional area, and volume </span><span>of the root of the mandibular M1 and M2 were measured using micro-CT</span><span> analysis. Non-decalcified thin-slice specimens of sagittal sections of the M1 were obtained at the age of 20 weeks, and the roots were observed. The root length of all roots in the Extraction group was significantly longer than that in the other groups. The root width and cross-sectional area at the apical side 1/4 of all roots in the Extraction group were significantly smaller than those in the other groups. The root volume of the M1 mesial root in the Extraction group was significantly smaller than that in the other groups.</span><span> </span><span>This study clarified that when masticatory stimulus in the immature teeth is reduced by the extraction of opposing teeth and a powder diet, the root length increases due </span><span>to the promotion of cellular cementum addition at the apex, and the root</span><span> width and cross-sectional area decrease due to the suppression of cellular cementum addition at the apical side 1/4 of the roots.</span>
文摘The effects of childhood masticatory function loss and soft foods on the mandibular condyle have been the subject of much research. However, the corresponding bone turnover is not fully understood. The purpose of the present study was to clarify the effects of a lack of teeth and a soft food diet during the growth period on bone turnover in the mandibular condyle. We divided 3-week-old Wistar rats into the following three groups: 1) Extraction group: The maxillary molars were extracted at the age of 4 weeks, and animals were fed powdered standard feed. 2) Powder group: Animals were fed powdered standard feed without tooth extraction. 3) Control group: Animals were fed solid standard feed without tooth extraction. Non-decalcified thin-slice specimens of sagittal sections of the mandibular condyle were obtained at the age of 20 weeks for histological analysis. We used micro-CT analysis and bone histomorphometry to measure bone volume (BV), bone mineral content (BMC), bone mineral density (BMD), bone microstructure, bone resorption, and osteogenesis in the mandibular condyle, and we compared the results among groups. In the extraction and the powder groups, we found deformation and disruption of the arrangement of chondrocytes, coagulation of chondrocytes, and duplication of the tidemark in the cartilage. We also found an increase in multinuclear osteoclasts in the cancellous bone. We found a reduction in BV, BMC, and BMD in the extraction and powder groups compared to the control group, as well as a reduction of bone volume, a lowering of osteogenesis parameters, and an increase in bone resorption parameters in the secondary cancellous bone. These results suggest that a lack of teeth and a soft food diet during the growth period cause a decline in bone microstructure, a decrease in osteogenesis, and an increase in bone resorption.
