• The korean journal of orthodontics
• /
• v.52 no.2
• /
• pp.150-160
• /
• 2022

Objective: To provide reliable prediction models based on dentoskeletal and soft tissue variables for customizing maxillary incisor positions and to optimize digitalized orthodontic treatment planning. Methods: This study included 244 Chinese women (age, 18-40 years old) with esthetic profiles after orthodontic treatment with fixed appliances (133 in group I: 1° ≤ The angle between the nasion [N]-A point [A] plane and the N-B point [B] plane [ANB] ≤ 4°; 111 in group II: 4° < ANB ≤ 7°). Dental, skeletal, and soft tissue measurements were performed on lateral cephalograms of the participants. Correlation and multiple linear regression analyses were used to determine the influence of dentoskeletal and soft tissue variables on maxillary incisor position. Results: The ideal anteroposterior position of the maxillary incisor varied between sagittal skeletal patterns. The position of the maxillary incisor correlated with the sagittal discrepancy between the maxilla and the mandible (ANB), protrusion of the midface, nasal tip projection, development of the chin, and inclination of both the maxillary and mandibular incisors. Distance from the maxillary central incisor to nasion-pogonion plane predicted using multiple linear regression analysis was accurate and could be a practical measurement in orthodontic treatment planning. Conclusions: Instead of using an average value or norm, orthodontists should customize a patient's ideal maxillary incisor position using dentoskeletal and soft tissue evaluations.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.3
• /
• pp.236-248
• /
• 2013

In this study, 37 subjects with normal facial shape and normal occlusion are classified and reference value for such classification was investigated. Difference in position of maxillary incisor was studied according to the cl assification. Moreover, by investigating correlation between factors affecting forehead morphology and positio n of maxillary incisor, following results have been obtained. 1. Morphology of forehead can be classified as angular type, round type, straight type, and concave type. 2. There were no specific reference value for evaluation of forehead morphology but possibilities of evaluating forehead morphology using S value and forehead length (Tri-Gla) still remain. 3. There were no correlation between forehead morphology and position of maxillary incisor. 4. Forehead inclination and Andrew analysis show statistically significant negative correlation. That is, as forehead inclination increases, maxillary incisor is positioned posteriorly and this relationship can be shown as following equation, Andrew analysis = -0.39*Forehead inclination.

• The korean journal of orthodontics
• /
• v.21 no.3
• /
• pp.617-634
• /
• 1991

The retraction of anterior teeth is one of the fundamental methods in orthodontic treatment and a proper position and angulation of anterior teeth after the retraction are very important for esthetics, stability, and function of teeth. In this research we analyzed, by Finite Element Method, the stress distribution on the periodontal ligament according to the variation of force and moment applied on the crown and predict the pattern of movement of maxillary central incisor. At the same time, the amount of force and moment caused by activation of the loop which was used for retraction of maxillary central incisor was analyzed by Finite Element Method. We observed the following results: 1) We could control the stress distribution on the periodontal ligament by proper moment/force ratio on maxillary right central incisor and predict the pattern of movement of maxillary right central incisor. 2) The amount of stress on the periodontal ligament as well as the moment/force ratio demanded by each pattern of movement increased as the destruction of alveolar bone was worse. 3) The moment/force ratio demanded by each pattern of movement decreased as the angle between the maxillary central incisor and occlusal plane decreased. 4) The force with the open loop was shown to be large compared to that with the closed loop. Also, the force with the helix decreased by 30% compared to that without the helix. 5) Under the same conditions we observed a larger moment/force ratio when the open loop and/or the helix were used.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.4
• /
• pp.672-678
• /
• 2007

Anatomic abnormalities of teeth development include the presence of a single maxillary central incisor at midline instead of two central incisors. The incidence of cases with a single maxillary central incisor is approximately 1 in every 50,000 live births. single median maxillary central incisor(SMMCI) may be a integral manifestation of any one of a number of syndromes. It has been reported an association with several midline disorders which have varied in severity. A SMMCI has also been reported as an isolated finding. But in some cases, it has been considered as an incomplete expression of autosomal dominant holoprosencephaly. So any patient who appears for treatment with a SMMCI should be referred for a detailed medical examination to exclude other associated systemic abnormalities and for mutation analysis to facilitate correct diagnosis and the provision of appropriate genetic counseling. Early orthodontic treatment is needed to minimalize emotional trauma of child. This case report was about three patients with a SMMCI as isolated finding. The purpose of these case reports was to present cases of single maxillary central incisor not associated with other disorders.

• The korean journal of orthodontics
• /
• v.11 no.2
• /
• pp.143-150
• /
• 1981

Casts of 180 Korean male and female with normal occulsion of early permanent dentition (from dental age of Hellman III C, to IV A) were studied to measure the mesiodistal crown diameters and to calculate the coefficients of correlation between the teeth. From the study, the following conclusions were made: 1. Mesiodistal dimension of maxillary central incisors, canines, first molars and mandibular canines, first premolars, second premolars and first molars of male are larger than that of female. 2. Korean teeth are roughly intermediate between those of American Caucasian and those of American Negro. 3. In both sexes, the relation between the first and second premolars appeared highly correlated not only in the maxillary arch but also in the mandibular arch, and the relation between the central incisor and lateral incisor appeared highly correlated in the mandibular arch. 4. The relation between the maxillary and mandibular first premolars appeared highly correlated in both sex, and the relation between the maxillary canine and mandibular canine in male as well as between the maxillary central incisor and mandibular central incisor in female appeared highly correlated.

• The korean journal of orthodontics
• /
• v.48 no.6
• /
• pp.367-376
• /
• 2018

Objective: This study was performed to investigate the changes in alveolar bone after maxillary incisor intrusion and to determine the related factors in deep-bite patients. Methods: Fifty maxillary central incisors of 25 patients were evaluated retrospectively. The maxillary incisors in Group I (12 patients; mean age, $16.51{\pm}1.32years$) were intruded with a base-arch, while those in Group II (13 patients; mean age, $17.47{\pm}2.71years$) were intruded with miniscrews. Changes in the alveolar envelope were assessed using pre-intrusion and post-intrusion cone-beam computed tomography images. Labial, palatal, and total bone thicknesses were evaluated at the crestal (3 mm), midroot (6 mm), and apical (9 mm) levels. Buccal and palatal alveolar crestal height, buccal bone height, and the prevalence of dehiscence were evaluated. Two-way repeated measure ANOVA was used to determine the significance of the changes. Pearson's correlation coefficient analysis was performed to assess the relationship between dental and alveolar bone measurement changes. Results: Upper incisor inclination and intrusion changes were significantly greater in Group II than in Group I. With treatment, the alveolar bone thickness at the labial bone thickness (LBT, 3 and 6 mm) decreased significantly in Group II (p < 0.001) as compared to Group I. The LBT change at 3 mm was strongly and positively correlated with the amount of upper incisor intrusion (r = 0.539; p = 0.005). Conclusions: Change in the labial inclination and the amount of intrusion should be considered during upper incisor intrusion, as these factors increase the risk of alveolar bone loss.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.34 no.5
• /
• pp.326-331
• /
• 2012

Purpose: Length measurement from maxillary anterior teeth root tip to nasal floor is incorrect in panoramic radiography. Comparison of cone beam computed tomography (CBCT) and panoramic radiography should be helpful in determining the vertical length. Methods: Sixty nine patients were taken CBCT and panoramic radiography of the maxillary anterior. First measurement is length of parallel lines from the central incisor and lateral incisor root tip to nasal floor on CBCT. Second measurement is length of perpendicular lines from the central incisor and lateral incisor root tip to nasal floor on CBCT. Third measurement is length from the central incisor and lateral incisor root tip to nasal floor on panoramic radiographys. Results: In the first measurement of the maxillary central incisors, an average of $11.36{\pm}2.49$ mm in males and $10.49{\pm}2.17$ mm in females. In the second measurement of the maxillary central incisors, $10.41{\pm}2.42$ mm in males and $9.18{\pm}2.08$ mm in females. In the third measurement of the maxillary central incisors, $10.71{\pm}2.20$ mm in males and $9.27{\pm}2.10$ mm in females. In the first measurement of the maxillary lateral incisors, an average of $13.40{\pm}2.04$ mm in males and $11.96{\pm}2.20$ mm in females. In the second measurement of the maxillary lateral incisors, $11.25{\pm}1.82$ mm in males and $10.06{\pm}1.68$ mm in females. In the third measurement of the maxillary lateral incisors, $11.47{\pm}2.01$ mm in males and $10.13{\pm}1.70$ mm in females. Conclusion: The vertical length from root tip to nasal floor was longer in male than female (P>0.05). First measurement was longer than third measurement (P<0.05). This is the actual placement of the implant site measured on the vertical length than the length of the panorama means that there are a few more free. The first measurement was longer than 114% over the third measurement.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.7 no.1
• /
• pp.21-32
• /
• 1980

The purpose of this study is to determine the developmental relationship between the maxillary primary central incisors and their permanent successor. The auther took 315 cases of lateral cephalogram of the children (males were 171, females were 141) Angular change of the teeth and horizontal and vertical linear change were observed. The obtained results were as follows: 1. The inclination of the long axes of both incisor teeth was relatively stable and labio-version of both incisore was significant at 7 years of age. 2. The distance between the incisal edge of the permanent central insisor and the resorbing apex of the primary maxillary central incisor remained within 2mm of each other, 3. Vertical growth of the maxillary anterior portion was greater than horizontal growth from 6 to 7 years of age. 4. There was not a significant sexual difference.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.24 no.3
• /
• pp.568-574
• /
• 1997

Inverted maxillary incisor is a state in which the maxillary incisor rotates to the upward position. The present report provides two examples of correction of inverted maxillary incisors with surgical intervention & orthodontic appliance. Through surgical exposure & direct bonding of lingual button, the central incisor were brought into proper eruption path with elastic traction. The case 1 & 2 were both treated successfully. The results showed the good position of treated teeth and satisfactory esthetics and adequate width of keratinized gingiva were achieved. Careful differential diagnosis procedure is needed in order to avoid dissatisfactory results and the treatment approaches taken in this case report provided an esthetic and functional results.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.36 no.5
• /
• pp.375-379
• /
• 2010

Introduction: In the management of dentofacial deformities, variable movement of the maxilla can be made possible by a Le Fort I osteotomy. Posterior impaction of the maxilla necessary for rotation of the maxillomandibular complex enhances the functions and esthetic results. In cases of posterior impaction of the maxilla, an increase in the figure of the occlusal plane angle and incisor inclination can occur. This study reports the relationship between the amount of posterior impaction and the change in the occlusal plane angle and incisor inclination in a Le Fort I osteotomy by preoperative and postoperative lateral cephalograms. Materials and Methods: Twenty patients who had undergone orthognathic surgery in Dong-A University Medical Center participated in this study. Lateral cephalometrics, within 3 weeks prior to surgery and 3 days after surgery, were used for analysis. Pre and postoperative measurements of the occlusal plane angle and incisal inclination based on the Frankfort horizontal (FH) plane were performed. X and Y were defined as the amount of vertical change in the upper incisor tip and the amount of vertical change in the upper first molar mesial cup tip through the operation. The amount of final posterior maxillary impaction was determined by subtracting Y from X, which is the difference in vertical height. According to the amount of posterior maxillary impaction, the change in the occlusal plane angle and incisal inclination was measured. Results: The average posterior maxillary impaction was 2.91 mm and the average change in the occlusal plane angle and incisal inclination was $6.54^{\circ}$after surgery. As a result, each mm of posterior maxillary impaction changed the occlusal plane angle and incisal inclination by $2.25^{\circ}$. Statistically, there was high significance. Two cases were observed: one with the same amount of posterior maxillary impaction performed on both the right and left showing $2.20^{\circ}$, and the other with a different amount of posterior maxillary impaction performed showing $2.35^{\circ}$. In this case, there was no significance difference between the two cases. Conclusion: Each mm of posterior maxillary impaction changes the occlusal plane angle and incisal inclination by an average of $2.25^{\circ}$. In posterior maxillary impaction, there was no significant difference in the amount of change in the occlusal plane angle and incisal inclination regardless of whether there was an equal amount of posterior maxillary impaction on both sides. This study is expected to help in the presurgical orthodontic preparation and presurgical treatment planning.