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1.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-1006542

RESUMO

Objective@#This study aimed to explore the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology in patients with high-angle skeletal Class Ⅱ open bite, aiming to provide a reference for clinical treatment.@*. Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. CBCT images of eighty-one untreated patients (40 anterior open bite patients and 41 normal overbite patients) with high-angle skeletal Class Ⅱ malocclusion were selected before treatment. Dolphin software was used to study the root length of maxillary and mandibular anterior teeth and central incisor crown-root morphology, and the differences between the two groups were analyzed.@*Results@#There was no statistical significance in the root length of maxillary lateral incisor and canine between the open bite group and the normal overbite group, significant differences were found in the root length of maxillary central incisor (11.12 ± 1.37) mm、mandibular central incisor(10.15 ± 1.09)mm, mandibular lateral incisor(11.27 ± 1.15)mm and mandibular canine(12.81 ± 1.48)mm between the open bite group and the normal overbite group(P<0.05). On the other hand, the two groups were significantly different in crown-root morphology of the maxillary central incisor (1.10° ± 3.62° vs. 4.53° ± 2.30°, P<0.01) but not in the mandibular central incisor.@*Conclusion@#The root length of the maxillary central incisor, mandibular central incisor, mandibular lateral incisor, mandibular canine in high-angle Class Ⅱ open bite patients is shorter than that in high-angle Class Ⅱ normal overbite patients, and the long axis of the crown of the maxillary central incisor in high-angle Class Ⅱ open bite patients obviously deviates toward the labial side relative to the long axis of the root. The crown-root angle is smaller, which is beneficial to torque control or adduction movement of the anterior teeth in high-angle Class Ⅱ open bite patients.

2.
Dental press j. orthod. (Impr.) ; 27(1): e222079, 2022. tab, graf
Artigo em Inglês | LILACS-Express | LILACS, BBO - Odontologia | ID: biblio-1375247

RESUMO

ABSTRACT Objective: To determine the discrepancy of crown-root morphology of anterior teeth, using cone-beam computed tomography (CBCT), and to provide a guidance for proper torque expression. Methods: A total of eligible 200 CBCT were imported into Invivo v. 5.4 software, to obtain the middle labio-lingual sections of anterior teeth. AutoCAD 2007 software was applied to measure the crown-root angulation (Collum angle) and the angle formed by a tangent to the center of the labial surface and the long axis of the crown (labial surface angle). SPSS 18.0 was used for statistical comparisons of the two measurements, at the level of p< 0.05, and the Pearson correlation analysis was applied to investigate the association between the two measurements. Results: The value of Collum angle in maxillary central incisor was close to 0°. Significantly negative Collum angle in lateral incisors and maxillary canine, and positive value in mandibular canine were detected (p < 0.001). The labial surface angle in canine was significantly greater than the intra-arch incisors (p< 0.001), and no significant difference was detected between the central and lateral incisors (p > 0.05). Notably, there was also a significant positive correlation between the two measurements. Conclusions: The crown-root angulations were greatly different among anterior teeth. Accompanying the obvious crown-root angulations, the canines both in maxillary and mandibular arches presented considerable labial surface curvatures. Hence, equivalent deviation during bracket bonding might cause greater torque expression error and increase the risk of alveolar fenestration and dehiscence.


RESUMO Objetivo: Determinar a discrepância na morfologia coroa-raiz de dentes anteriores, utilizando tomografia computadorizada de feixe cônico (TCFC), e fornecer parâmetros para a expressão apropriada do torque. Método: No total, 200 tomografias elegíveis foram importadas para o software Invivo 5.4 para obtenção das secções médias vestibulolinguais dos dentes anteriores. Osoftware AutoCAD 2007 foi usado para medir a angulação coroa-raiz (ângulo Collum) e o ângulo formado por uma tangente ao centro da superfície vestibular da coroa e o longo eixo da coroa (ângulo da superfície vestibular). O software SPSS 18.0 foi utilizado para as comparações estatísticas das duas medições, com nível de significância de p< 0,05, e a análise de correlação de Pearson foi aplicada para investigar a associação entre as duas medições. Resultados: O valor do ângulo Collum do incisivo central superior foi próximo a 0°. Foram detectados valores significativamente negativos para o ângulo Collum nos incisivos laterais e caninos superiores, mas valores positivos nos caninos inferiores (p< 0,001). O ângulo da superfície vestibular no canino foi significativamente maior do que nos incisivos intra-arcada (p< 0,001), e nenhuma diferença significativa foi detectada entre incisivos centrais e laterais (p> 0,05). Também foi observada uma correlação positiva significativa entre as duas medições. Conclusões: As angulações coroa-raiz foram muito diferentes entre os dentes anteriores. Os caninos superiores e inferiores apresentaram considerável curvatura na superfície vestibular, associada a uma evidente angulação coroa-raiz. Consequentemente, desvios durante a colagem de braquetes podem desencadear maior erro na expressão de torque e aumentar o risco de fenestração alveolar e deiscência, sendo necessária uma avaliação antes da colagem.

3.
Prog Orthod ; 20(1): 20, 2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-31111270

RESUMO

BACKGROUND: To determine the discrepancy of crown-root morphology of central incisors among different types of skeletal malocclusion using cone-beam computed tomography (CBCT) and to provide guidance for proper torque expression of anterior teeth and prevention of alveolar fenestration and dehiscence. METHODS: In this retrospective study, a total of 108 CBCT images were obtained (ranging from 18.0 to 30.0 years, mean age 25.8 years). Patients were grouped according to routine sagittal and vertical skeletal malocclusion classification criteria. The patients in sagittal groups were all average vertical patterns, with Class I comprised 24 patients-14 females and 10 males; Class II comprised 20 patients-13 females and 7 males; and Class III comprised 22 subjects-13 females and 9 males. The patients in vertical groups were all skeletal Class I malocclusions, with low angle comprised 21 patients-12 females and 9 males; average angle comprised 24 patients; and high angle comprised 21 patients-11 females and 10 males. All the CBCT data were imported into Invivo 5.4 software to obtain a middle labio-lingual section of right central incisors. Auto CAD 2007 software was applied to measure the crown-root angulation (Collum angle), and the angle formed by a tangent to the central of the labial surface of the crown and the long axis of the crown (labial surface angle). One-way analysis of variance (ANOVA) and Scheffe's test were used for statistical comparisons at the P < 0.05 level, and the Pearson correlation analysis was applied to investigate the association between the two measurements. RESULTS: The values of Collum angle and labial surface angle in maxillary incisor of Class II and mandibular incisor of Class III were significantly greater than other types of sagittal skeletal malocclusions (P < 0.05); no significant difference was detected among vertical skeletal malocclusions. Notably, there was also a significant positive correlation between the two measurements. CONCLUSIONS: The maxillary incisor in patients with sagittal skeletal Class II malocclusion and mandibular incisor with Class III malocclusion present remarkable crown-root angulation and correspondingly considerable labial surface curvature. Equivalent deviation during bracket bonding may cause greater torque expression error and increase the risk of alveolar fenestration and dehiscence.


Assuntos
Má Oclusão Classe III de Angle , Má Oclusão , Adulto , Tomografia Computadorizada de Feixe Cônico , Coroas , Feminino , Humanos , Incisivo , Masculino , Maxila , Estudos Retrospectivos
4.
Journal of Medical Postgraduates ; (12): 280-285, 2016.
Artigo em Chinês | WPRIM (Pacífico Ocidental) | ID: wpr-487228

RESUMO

Objective Maxillary canine palatal impaction is a common deformity in stomatology and its etiology remains dis-putable.The aim of this study is to investigate the crown-root morphology of the adjacent lateral incisors in patients with palatally impacted maxillary canines using cone-beam computed tomography ( CBCT) in order to explore its etiology. Methods Using CBCT scanning, we examined 94 maxillary canines in 84 patients, including 27 palatally impacted maxillary canines in 24 patients ( the experi- mental group) , 37 buccally impacted maxillary canines in 30 age-and sex-matched subjects ( control group A) , and 30 normal maxil-lary canines in 30 age-and sex-matched subjects ( control group B) .We selected some necessary reference planes, measured the ori-entation and position of the chosen canines, and studied the morphology of the adjacent lateral incisors by CS 3D imaging, followed by statistical analysis of 17 of the linear variables obtained. Results Compared with control group A, the experimental group showed significantly shorter tooth length ([22.930 ±1.849]mm vs [21.240 ±1.651]mm, P<0.05), crown length ([9.270 ±0.559]mm vs [8.150 ±0.889] mm, P<0.05), and mesiodistal width at 4 mm to the cementoenamel junction (CEJ) ([7.260 ±0.579]mm vs [5.900 ±0.581] mm, P<0.05) as well as shorter buccolingual width at the CEJ level, mesiodistal width at 4 mm to the CEJ, buc-colingual width at 4 mm apical to the CEJ, distance from the canine cusp to the coronal and occlusal planes, and coronal angulation of the canine (all P<0.05).There was a negative correlation between maxillary canine palatal impaction and age (P<0.05). Conclusion One of the main causes of maxillary canine palatal impaction is that the adjacent lateral incisor is too small to provide suf-ficient guidance to the canine.The severity of maxillary canine palatal impaction increases with the age of the patient.

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