A Comparative Study Of Bolton Index In The Youth And Middle-Old Age

Objective： To Investigate the changes of Bolton index, Maxillary andmandibular dental size and dental size discrepancy in the youth and middle-oldaged.Method:191youth dental plaster cast from malocclusion patients and63middle-old aged dental plaster casts from snoring or obstructive sleep apnea/hypopnea syndrome patients were selected.12dental size between first molar,width of maxillary lateral incisor, anterior and overall Bolton ratios and teethsize discrepancy were measured and calculated. Statistical analysis on the datawas done.Results:⑴there were not significant difference between youth andmiddle-old aged in Bolton anterior and overall ratios (P>0.05).⑵12maxillary dental size of the youth is larger than the middle-old aged (P <0.01),while there were not significant in other items(P <0.01), but the mean of themiddle-old aged is smaller.⑶the prevalence of anterior and overall TSD in theyouth is31.4%and42.4%, while19.05%and15.9%in the middle-old aged.⑷There is a significant difference(P <0.05) between the two groups in widthof lateral incisor which was7.5mm in the youth and7.2mm in the middle-old aged.Conclusion:1. Bolton index could not change by age, Although the dentalsize reduced, but the maxillary dental size has been reduced by1.5mm eachside, and premolar and first molar region was significantly reduced.2. Teeth sizediscrepancy of middle-old aged and Lateral incisor was not the main cause ofmalocclusion.