Prevalence of 3-rooted primary mandibular second molars among chinese patients.
OBJECTIVE
The purpose of this study was to determine the prevalence of 3-rooted primary mandibular second molar teeth in Chinese patients via vertical bitewing radiography.


METHODS
Vertical bitewing radiographs of 227 patients previously obtained from the Department of Pediatric Dentistry, Taichung Veterans General Hospital, Taichung City, Taiwan, from June 2004 to July 2007 were retrospectively screened and examined. Images of 185 patients (92 boys and 93 girls; mean age=5.6 [range=2.5-11.9] years old) with bilateral primary mandibular second molars were studied. The gender, symmetry, and frequencies of occurrence of 3-rooted primary mandibular second molars were compared.


RESULTS
Eighteen (9%) 3-rooted primary mandibular second molars were found in the 185 patients, with a bilateral incidence of a symmetrical distribution of 28% (5/18). The prevalence of 3-rooted primary second molars did not differ significantly between the mandible's right and left sides (P<.41), or with gender (P<.31).


CONCLUSIONS
The data presented here indicate that approximately one tenth of Chinese individuals have a 3-rooted primary mandibular second molar and that this condition is bilaterally symmetric in approximately one third of such individuals in a Taiwan hospital.
Liu
Jeng-Fen
JF
Section of Pediatric Dentistry, Taichung Veterans General Hospital, Taichung, Taiwan.
Dai
Pei-Wei
PW
Chen
San-Yue
SY
Huang
Heng-Li
HL
Hsu
Jui-Ting
JT
Chen
Wil-Lie
WL
Tu
Ming-Gene
MG
D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible; D008963:Molar / Q000002:abnormalities*; D015995:Prevalence; D016300:Radiography, Bitewing / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012737:Sex Factors; D014092:Tooth Root / Q000002:abnormalities*; D014094:Tooth, Deciduous / Q000002:abnormalities*