Cone-beam computed tomography for the assessment of root–crown ratios of the maxillary and mandibular incisors in a Korean population

Abstract

ObjectiveThis retrospective, cross-sectional study aimed to establish reference data for normal crown and root lengths and the root–crown ratios (R/C ratios) for the mature maxillary and mandibular incisors in a Korean population by using cone-beam computed tomography (CBCT).MethodsWe included 672 Korean patients (141 men and 531 women; mean age, 27.2 ± 7.7 years) who underwent CBCT examinations during various dental treatments. Crown and root lengths and the R/C ratios of the maxillary and mandibular incisors were measured using CBCT data, which were analyzed to detect significant differences between demographic factors as well as sagittal and vertical skeletal or occlusal relationships.ResultsTeeth of the same type in each half-arch were symmetrical. The mean R/C ratios varied from 1.1 to 1.2 for the maxillary incisors and from 1.3 to 1.4 for the mandibular incisors. Crown and root lengths were greater in men than in women, regardless of tooth type. Root lengths and R/C ratios for the mandibular incisors were significantly greater in patients with skeletal Class II malocclusion or an excessive overjet than in the other patients. The R/C ratios for the mandibular incisors were lower in patients with an open bite than in those with a normal or deep bite. Moreover, the R/C ratios for the mandibular incisors increased with age.ConclusionsThe data obtained in our study can serve as reference values for crown and root lengths and the R/C ratios for the maxillary and mandibular incisors in the Korean population.

A prospective, split-mouth, clinical study of orthodontic titanium miniscrews with machined and acid-etched surfaces

“…Host-related variables included age (,20 years, !20 years), 10 sagittal skeletal pattern (Class I, ANB 0À48; Class II, .48; Class III, ,08), 11 vertical skeletal pattern (high, SN-MP .378; normal, SN-MP 27-378; low, SN-MP ,278), 12 overjet (normal, 0-4 mm; excessive overjet .4 mm; crossbite ,0 mm), and overbite (normal, 0-4 mm; deep bite .4 mm; open bite ,0 mm). 13 Miniscrew-related variables included surface treatment type (machined vs acid-etched), insertion site (maxilla vs mandible), and miniscrew purpose (en masse retraction anchorage, retraction; total arch distal movement, distalization; maxillary molar intrusion, intrusion). The model-building strategy involved the inclusion of any variable for which the bivariate test yielded a P value of ,.05.…”

Analysis of the Tooth Length of Maxillary Incisors in Indonesian Mongoloid Race Population Based on Periapical Radiography

“…Another method is with cone beam computed tomography (CBCT) that Choi et al used in samples from Korean population. The tooth length on that study is maxillary central incisor 22.8±1.15 mm and maxillary lateral incisor 21.6±1.0 mm [7]. Research by Harris et al showed the tooth length of central incisor was 26.26±2.49 mm (males) and 25.21±2.14 mm (females), and lateral incisor was 25.15±2.42 mm (males) and 23.78±1.95 mm (females).…”

Ethnic differences in the root to crown ratios of the permanent dentition

“…Radiographic measurements of dental hard tissues are typically evaluated from panoramic, periapical, or Cone Beam Computed Tomography (CBCT) images . Most studies of the R/C ratios use panoramic radiographs, which are relatively inexpensive, accessible, and a part of most new patient exams .…”

“…Radiographic measurements of dental hard tissues are typically evaluated from panoramic, periapical, or Cone Beam Computed Tomography (CBCT) images. 13,17 Most studies of the R/C ratios use panoramic radiographs, which are relatively inexpensive, accessible, and a part of most new patient exams. [13][14][15]18 Although panoramic radiographs may have some limitations in terms of the accuracy of measurements compared with CBCT, they provide adequate information and are more practical for the assessment of changes in large number of teeth without additional exposure to radiation 18 .…”