ABSTRACT
Background@#Obesity and dental caries have common risk factors such as food intake, eating habits, and lifestyle. Nevertheless, there has been no consensus on the significant association between obesity and dental caries, and additional studies are needed.We investigated the relationship between obesity and dental caries in some college students in this pilot study. @*Methods@#Forty-two obese college students (body mass index [BMI]≥25) registered at a University Obesity Clinic and 19 normal students (18.5≤BMI＜25) were recruited. Oral examinations were conducted, and anthropometric data and blood samples were collected. The blood concentrations of low-density lipoprotein (LDL), high-density lipoprotein, and triglyceride were also measured. After controlling for dental plaque index, a univariate analysis of dental caries indicators related to obesity was performed; partial correlation analysis was also conducted. A nonparametric test was used for the analysis of gender-related trends due to the limited number of participants. @*Results@#The obese group had significantly fewer missing teeth (p=0.014), missing surfaces (p=0.035), filled surfaces (p=0.038), and decayed-missing-filled surfaces (p=0.020) than the normal group. There was no difference between the males in the normal and obese groups. The females in the obese group had significantly fewer missing teeth (p=0.003), missing surfaces (p=0.003), and decayed-missing-filled surfaces (p=0.046). Partial correlation analysis showed a weak negative correlation (r=−0.256) between the blood LDL concentration and decayed-missing-filled teeth. The other obesity and dental caries indicators were not correlated. @*Conclusion@#The blood cholesterol concentration had a negative relationship with dental caries, and there were fewer cases of dental caries in the obese group in this study. However, it is important to clarify the relationship between obesity and dental caries through a dietary survey or additional investigations considering other confounding factors.
ABSTRACT
The purpose of this study was to investigate the effect of rigidity of post core systems on stress distribution by the theoretical technique, finite element stress-analysis method. Three-dimensional finite element models simulating an endodontically treated maxillary central incisor restored with a zirconia ceramic crown were prepared and 1.5 mm ferrule height was provided. Each model contained cortical bone, trabecular bone, periodontal ligament, 4 mm apical root canal filling, and post-and-core. Six combinations of three parallel type post (zirconia ceramic, glass fiber, and stainless steel) and two core (Paracore and Tetric ceram) materials were evaluated, respectively. A 50 N static occlusal load was applied to the palatal surface of the crown with a 60degrees angle to the long axis of the tooth. The differences in stress transfer characteristics of the models were analyzed. von Mises stresses were chosen for presentation of results and maximum displacement and hydrostatic pressure were also calculated. An increase of the elastic modulus of the post material increased the stress, but shifted the maximum stress location from the dentin surface to the post material. Buccal side of cervical region (junction of core and crown) of the glass fiber post restored tooth was subjected to the highest stress concentration. Maximum von Mises stress in the remaining radicular tooth structure for low elastic modulus resin core (29.21 MPa) was slightly higher than that for high elastic modulus resin core (29.14 MPa) in case of glass fiber post. Maximum displacement of glass fiber post restored tooth was higher than that of zirconia ceramic or stainless steel post restored tooth.