title: Root canal morphology of permanent maxillary teeth in the Han nationality in Chinese Guanzhong area: a new modified root canal staining technique.
abstract: BACKGROUND
  The purpose of this study was to investigate the canal morphology of 504 maxillary permanent teeth of subjects of Han nationality in Chinese Guanzhong area.
  
  
  METHODS
  Maxillary permanent teeth were randomly collected in Guanzhong area. After regular preparation, the teeth were immersed into ink without preparing access cavities and then put into hyperbaric oxygen chamber (0.6 Mpa) for 2 hours to let the ink penetrate into root canal from apical foramen, apical deltas and foramen of lateral canals under stable positive pressure. After demineralization and clearing, the following observations were made: (1) number of root canals, (2) root canal configuration by using Vertucci's classification, (3) presence of lateral canals, and (4) frequency of apical deltas.
  
  
  RESULTS
  All the teeth were well-stained, and the fine details were well-revealed. Apical deltas (12.2%-83.3%) and lateral canals (13.7%-68.8%) could be frequently found in all types of maxillary teeth. Most of central incisors (95.8%), lateral incisors (91.4%), and canines (75.4%) displayed type I canal configuration, whereas most of first premolars (87.3%) and second premolars (72.3%) possessed 2 canals with type II, IV, or VI canal configuration. The majority of distobuccal roots and palatal roots of first molars (88.9%, 97.8%), second molars (92.0%, 94.0%), and third molars (87.5%, 91.6%) possessed type I canal configuration. The prevalence of mesiobuccal roots with type I configuration was 66.7% in maxillary first molars, 82% in second molars, and 62.5% in third molars.
  
  
  CONCLUSIONS
  The modified technique of canal staining can effectively reveal detailed root canal system. The canal configuration of maxillary teeth in subjects of Han nationality in Chinese Guanzhong area is consistent with previous reports in other races.
authors.affiliation: School of Stomatology, Fourth Military Medical University, Xi'an, China.
authors.forename: Xi-Li
authors.initials: XL
authors.lastname: Weng
authors.forename: Shi-Bin
authors.initials: SB
authors.lastname: Yu
authors.forename: Shou-Liang
authors.initials: SL
authors.lastname: Zhao
authors.forename: Han-Guo
authors.initials: HG
authors.lastname: Wang
authors.forename: Tong
authors.initials: T
authors.lastname: Mu
authors.forename: Rong-Yin
authors.initials: RY
authors.lastname: Tang
authors.forename: Xue-Dong
authors.initials: XD
authors.lastname: Zhou
mesh_terms: D001641:Bicuspid / Q000473:pathology; D002681:China; D004396:Coloring Agents; D003481:Cuspid / Q000473:pathology; D003648:Decalcification Technique; D003786:Dental Pulp Cavity / Q000473:pathology*; D005006:Ethnicity; D006801:Humans; D006931:Hyperbaric Oxygenation; D007180:Incisor / Q000473:pathology; D007281:Ink; D008437:Maxilla; D008963:Molar / Q000473:pathology; D013194:Staining and Labeling / Q000379:methods*; D019227:Tooth Apex / Q000473:pathology
chemical_list: D004396:Coloring Agents