The Bulletin of Tokyo Dental College
Print ISSN : 0040-8891
Volume 47, Issue 4
Displaying 1-4 of 4 articles from this issue
Original Articles
  • Syuntaro Nomoto, Satoru Matsunaga, Yoshinobu Ide, Shinichi Abe, Toshiy ...
    2006 Volume 47 Issue 4 Pages 149-156
    Published: 2006
    Released on J-STAGE: May 16, 2007
    JOURNAL FREE ACCESS
    The purpose of the present study was to evaluate stress distribution by finite element analysis in an accurate model simulating trabecular bone using micro-CT. Dentulous and edentulous maxillary jaws of Japanese adult cadavers were used (5 sides each; total, 10 sides). Imaging was performed using a micro-CT, followed by reconstruction with 3-D images. Finite element analysis models were developed using the maxilla with average bone morphometry. A load corresponding to occlusal force was applied in different loading conditions, followed by evaluation of stress distribution. In dentulous maxillas, a load was applied in the dental axis direction to the first molar crown (LD). In edentulous maxillas, a load was applied directly to a circular area 4mm in diameter (LER0) to a cylinder 4mm in diameter and 10mm in height (LER10) corresponding to the first molar area. Stress was concentrated in cortical bone around the first molar, trabecular bone and cortical bone at the maxillary sinus base in LD, cortical bone of the alveolar ridge in LER0, and trabecular bone around the cylinder and cortical bone at the maxillary sinus base in LER10. LER0 showed a stress distribution markedly different from that in LD. Compared with LER0, LER10 showed a stress distribution close to that in LD. A model simulating trabecular bone allows a more accurate evaluation of stress distribution.
    Download PDF (775K)
  • Takuro Yonezu, Nagako Ushida, Masashi Yakushiji
    2006 Volume 47 Issue 4 Pages 157-160
    Published: 2006
    Released on J-STAGE: May 16, 2007
    JOURNAL FREE ACCESS
    The aim of this investigation was to study the effects of prolonged breast- or bottle-feeding on dental caries in Japanese infants. This longitudinal study was conducted by means of a questionnaire and clinical examination of 592 children at 18 months, 2 years and 3 years of age. The children were divided into three groups: 1) children still being breast-fed at 18 months of age (n=42); 2) children still being bottle-fed at 18 months of age (n=45); and 3) children weaned off of breast- or bottle-feeding and with no nonnutritive-sucking habits at 18 months of age (n=205). Results showed that breast-feeding at 18 months of age produced many significant differences to the control children, including a higher prevalence of caries and higher number of dft. However, no significant differences were observed between bottle-fed and control children. In conclusion, our results suggest that prolonged breast-feeding at an early age before primary dentition has fully erupted is a risk factor for dental caries. Therefore, breast-fed children need to be monitored more closely, and aggressive methods of preventive care need to be instituted. It is also important to identify factors related to dental caries among breastfed children as soon as possible, and develop effective preventive programs.
    Download PDF (46K)
  • Takuro Yonezu, Kaori Yotsuya, Masashi Yakushiji
    2006 Volume 47 Issue 4 Pages 161-165
    Published: 2006
    Released on J-STAGE: May 16, 2007
    JOURNAL FREE ACCESS
    The aim of this study was to investigate the characteristics and risk factors of prolonged breast-feeding in children. A total of 105 children aged 18 months were screened for ongoing breast-feeding at a public health center. Of these, 105 children were selected for a more comprehensive examination, involving investigation of dietary, tooth-brushing habits and oral hygiene. The children were examined again, and initial and manifest caries were recorded at 24 months of age. As a result, 20 (19.0%) of the 105 children had caries at 24 months of age. Logistic regression analysis revealed an association between caries and bedtime breast-feeding (p=0.003). Oral hygiene at 18 months of age was also correlated with caries (p=0.015). It was concluded that reducing the frequency of feeding, early establishment of good oral hygiene habits and also regular visits to the dentist are essential in preventing nursing caries in prolonged breast-fed children.
    Download PDF (48K)
Short Communication
  • Kenichi Matsuzaka, Daisuke Sato, Kazuyuki Ishihara, Sadamitsu Hashimot ...
    2006 Volume 47 Issue 4 Pages 167-170
    Published: 2006
    Released on J-STAGE: May 16, 2007
    JOURNAL FREE ACCESS
    Defensins are known to play an important role in defense against bacteria. It is also known that immunity against infection is compromised with age. The purpose of this study was to evaluate the localization of human beta-defensin (HBD)-2 in human gingival epithelia according to age. Gingival epithelia in maxillary premolar buccal normal regions was immunohistochemically stained for HBD-2. Specimens were divided into two groups: 6 cases in a young group (<20 years old) and 7 cases in an elderly group (>50 years old). Expression of HBD-2 in gingival epithelium in young subjects was mostly detected in the superficial layer of the parakeratinized layer, while some areas of the spinous cell layer in elderly subjects were positive for HBD-2, as was the superficial layer. Two cases in the young group and 5 cases in the elderly group immunoreacted with HBD-2 in the spinous cell layer. Furthermore, immunoreaction was stronger in the elderly group. The results revealed HBD-2 positive cells in spinous cells in the elderly group and in the parakeratinized layer in the young group.
    Download PDF (108K)
feedback
Top