Relationships between the root-crown ratio and the loss of occlusal contact and high mandibular plane angle in patients with open bite

Uehara, Sawako; Maeda, Aya; Tomonari, Hiroshi; Miyawaki, Shouichi

doi:10.2319/042412-341.1

Cited by 12 publications

(11 citation statements)

References 22 publications

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“…Uehara et al25 reported that patients with an open bite exhibit an unfavorable R/C ratio and short roots, which may be associated with the loss of occlusal contacts. Occlusal hypofunction due to an open bite may decrease the possibility of incisal edge attrition and lead to atrophic changes in the periodontal ligament and root resorption.…”

Section: Discussionmentioning

confidence: 99%

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

Choi

Kim

et al. 2017

Korean J Orthod

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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.

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Section: Discussionmentioning

confidence: 99%

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

Choi

Kim

et al. 2017

Korean J Orthod

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“…Sample size was calculated considering an 80% of test power at a confidence level of 95%, with a mean intergroup difference to be detected of 2mm in the root length of maxillary central incisors, with a standard deviation of 1.60mm, as previously reported. 10 Although the required sample was 10 individuals per group, 24 subjects per group were included.…”

Section: Methodsmentioning

confidence: 99%

“…However, the root length was not directly measured. 8,9 In addition, only two studies that evaluated dental root length in panoramic radiographs 10 and root area in CBCT 11 concluded that patients with open bite, especially those with a high mandibular plane angle, have shorter dental roots and smaller root areas of the maxillary incisors, when compared to individuals with normal overbite. These studies mention that their findings may be related to the loss of occlusal contact in the anterior teeth.…”

Section: Introductionmentioning

confidence: 99%

Incisor root length in individuals with and without anterior open bite: a comparative CBCT study

Arriola-Guillén

Valera-Montoya

Rodríguez-Cárdenas

et al. 2020

Dental Press J. Orthod.

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Objective: This study aimed to compare the root length of maxillary and mandibular incisors between individuals with open bite versus matched individuals with adequate overbite. Methods: This comparative, matched and retrospective study included 48 cone beam computed tomographies (CBCTs) obtained at a university radiological center. Scans belonged to 24 individuals with open bite (overbite ≤ 0 mm) and 24 individuals with adequate overbite (controls). Both groups were matched by age, sex, malocclusion classification and skeletal characteristics (ANB and FMA angles). Root length of each maxillary and mandibular incisor was measured in millimeters (mm) in a sagittal section from a perpendicular line to the enamel cement junction until the root apex (384 length measurements were made). The means of root length in both groups were compared using t-tests. In addition, correlations between variables were evaluated with the Pearson correlation coefficient (α = 0.05). Results: In both groups, the root length of the upper central incisors was approximately 12 mm and the root length of the maxillary lateral incisors was approximately 13 mm (p˃ 0.05). Likewise, the root length of lower central incisors in both groups measured approximately 12 mm (p˃ 0.05). However, the mandibular lateral incisor roots of open bite patients were significantly longer than in the normal overbite patients (approximately 1 mm, p= 0.012 right side, p= 0.001 left side). Conclusions: Root length of maxillary incisors and central mandibular incisor is similar in individuals with or without open bite, but the mandibular lateral incisor roots in open bite patients were significantly longer than in the normal overbite patients.

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“…Occlusal hypofunction decreases alveolar bone mass, accelerates bone resorption, causes deficient root development, and leads to atrophic changes in the periodontal ligament, such as narrowing of the periodontal space, vascular constriction, and deformation of the mechanoreceptors. 4 5 6 Several previous studies 7 8 have reported that individuals with anterior open bite had a tendency to develop short dental roots from the incisors to the premolars that could be associated with occlusal hypofunction. Experimental findings in rat molars have included external root resorption during tooth movement, in association with hypofunction.…”

Section: Discussionmentioning

confidence: 99%

“…Occlusal hypofunction decreases alveolar bone mass, accelerates bone resorption, leads to atrophic changes in the periodontal ligament, causes deficient root development, and affects root surface area. 4 5 6 Some previous studies 7 8 have reported that individuals with anterior open bite had a tendency to develop short dental roots from the incisors to the premolars. Occlusal hypofunction due to anterior open-bite malocclusion plays an important role in dental root morphology, leading to the risk of root resorption during tooth movement.…”

Section: Introductionmentioning

confidence: 99%

Root surface areas of maxillary permanent teeth in anterior normal overbite and anterior open bite assessed using cone-beam computed tomography

et al. 2017

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PurposeThe aim of this study was to compare the root surface areas of the maxillary permanent teeth in Thai patients exhibiting anterior normal overbite and in those exhibiting anterior open bite, using cone-beam computed tomography (CBCT).Materials and MethodsCBCT images of maxillary permanent teeth from 15 patients with anterior normal overbite and 18 patients with anterior open bite were selected. Three-dimensional tooth models were constructed using Mimics Research version 17.0. The cementoenamel junction was marked manually. The root surface area was calculated automatically by 3-Matic Research version 9.0. The root surface areas of each tooth type from both types of bite were compared using the independent t-test (P<.05). The intraclass correlation coefficient was used to assess intraobserver reliability.ResultsThe mean root surface areas of the maxillary central and lateral incisors in individuals with anterior open bite were significantly less than those in those with normal bite. The mean root surface area of the maxillary second premolar in individuals with anterior open bite was significantly greater than in those with normal bite.ConclusionAnterior open-bite malocclusion might affect the root surface area, so orthodontic force magnitudes should be carefully determined.

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Relationships between the root-crown ratio and the loss of occlusal contact and high mandibular plane angle in patients with open bite

Abstract: Patients with open bite, especially those with a high Mp angle, have an unfavorable R/C ratio and short dental roots in some teeth, which may be related to the loss of OC.

Cited by 12 publications

References 22 publications

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

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

Incisor root length in individuals with and without anterior open bite: a comparative CBCT study

Root surface areas of maxillary permanent teeth in anterior normal overbite and anterior open bite assessed using cone-beam computed tomography

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