ABSTRACT
PURPOSE: This study assessed the accuracy of age estimates produced by a regression equation derived from lower third molar development in a Thai population. MATERIALS AND METHODS: The first part of this study relied on measurements taken from panoramic radiographs of 614 Thai patients aged from 9 to 20. The stage of lower left and right third molar development was observed in each radiograph and a modified Gat score was assigned. Linear regression on this data produced the following equation: Y=9.309+1.673 mG+0.303S (Y=age; mG=modified Gat score; S=sex). In the second part of this study, the predictive accuracy of this equation was evaluated using data from a second set of panoramic radiographs (539 Thai subjects, 9 to 24 years old). Each subject's age was estimated using the above equation and compared against age calculated from a provided date of birth. Estimated and known age data were analyzed using the Pearson correlation coefficient and descriptive statistics. RESULTS: Ages estimated from lower left and lower right third molar development stage were significantly correlated with the known ages (r=0.818, 0.808, respectively, P≤0.01). 50% of age estimates in the second part of the study fell within a range of error of ±1 year, while 75% fell within a range of error of ±2 years. The study found that the equation tends to estimate age accurately when individuals are 9 to 20 years of age. CONCLUSION: The equation can be used for age estimation for Thai populations when the individuals are 9 to 20 years of age.
Subject(s)
Humans , Age Determination by Teeth , Asian People , Forensic Dentistry , Linear Models , Molar, Third , Parturition , Radiography, PanoramicABSTRACT
The objective of the study is to compare xerostomia condition, hyposalivation and some oral factors between diabetic and non-diabetic subjects. Samples of the study were 42 diabetic patients who were treated diabetes in Bangkruai hospital and other 46 non-diabetic patients who visited out-patient department of the same hospital during February and March 2008. Data was collected by using questionnaire on general history and diabetic history, and xerostomia assessment form. Salivary flow rate was investigated by spitting method. Oral condition was examined as directed by WHO. Data was analyzed by Chi-square, Independent t-test, Mann-Whitney U test and Regression statistics. It is found that there is no statistical difference of salivary flow rate, caries score, and xerostomia condition between diabetic and non-diabetic group. Contrarily, hyposalivary condition and number of teeth remaining in the mouth are related to diabetic condition statistically.Key words: xerostomia, hyposalivation, salivary flow rate, diabetes mellitus
ABSTRACT
The aims of this study were to measure and compare the mean shear bond strength of different adhesive systems for bonding orthodontic brackets to fluorotic and normal teeth. One hundred and twenty premolar teeth were divided into six groups (N=20), brackets were bond and fixed to the sample teeth. Groups 1, 2 and 3 contained normal teeth bonded with System TM1+, UniteTM and Super-Bond C\&B. Groups 4, 5 and 6 contained fluorotic teeth bonded with SystemTM1+, UniteTM and Super-Bond C\&B. Thermocycling was performed at 5+2○C and 55+2○C for 1,000 cycles. Shear bond strength was measured using an universal testing machine at a crosshead speed of 0.5 mm/min. The data were analyzed using two-way ANOVA. The results indicated the mean shear bond strength values of all adhesives used on normal teeth were significantly greater than those used on fluorotic teeth (p=0.000). With both normal and\ fluorotic teeth, the mean shear bond strength value of Super-Bond C\&B was significantly greater than the mean shear bond strength values of SystemTM1+and UniteTM (p=0.000).\ Keywords: shear bond strength, adhesive systems, fluorotic teeth