Factors affecting treatment duration of labial inversely impacted maxillary central incisors

Factors affecting local alveolar bone thickness in unilateral maxillary canine-lateral incisor transposition

INTRODUCTION

This study aimed to use 3-dimensional data to investigate the factors affecting local alveolar bone thickness in unilateral maxillary canine-lateral incisor transposition.

METHODS

Pretreatment cone-beam computed tomography data of 34 patients with unilateral maxillary canine-lateral transposition were imported into Dolphin Imaging software (version 11.8; Dolphin Imaging and Management Solutions, Chatsworth, Calif) for 3-dimensional reconstruction. The age, gender, and type of transposition at the beginning of treatment were recorded. The thickness and height of the transposed canine, the labiopalatal and distomedial distance from the transposed canine to the apex of the lateral incisor, the inclination of the transposed lateral incisor, the apical height of the lateral incisor, and the alveolar bone thickness in the apical plane were measured. Multiple linear regression analyses were applied to investigate the factors affecting alveolar bone thickness in the apical plane of the transposed lateral incisor. Two sample t test were applied to assess the difference of alveolar bone thickness in patients of different ages.

RESULTS

The 10 boys and 24 girls had a mean age of 12.26 ± 2.34 years. In all 34 participants, the apical alveolar bone thickness of transposed lateral incisors was significantly higher than that of the unaffected side (P <0.05). Based on multiple regression analyses, factors associated with a wider alveolar bone thickness were as follows: age (β = -0.237; P = 0.008), the labiopalatal distance from the transposed canine to the apex of the lateral incisor (β = 0.675; P <0.001), and the inclination of the transposed lateral incisor (β = 0.048; P = 0.032). Patients aged <11 years had significantly thicker alveolar bone than that of patients aged >11 years (P <0.05).

CONCLUSIONS

Patients with younger age, greater lateral incisor inclination, and greater labiopalatal distance between canine and lateral incisor had more alveolar bone thickness. Early treatment permits tooth movement within the thicker alveolar bone.

Labial inverse dilaceration of bilateral maxillary central incisors: A case report

BACKGROUND

Dilaceration is a rare dental developmental anomaly characterized by an abrupt deviation along the longitudinal axis of the root in which an angulation forms between the root and the crown. Here, we report on dilacerated bilateral maxillary central incisors in mixed dentition.

CASE SUMMARY

A 10-year-old girl presented with a chief complaint of unerupted central incisors. An oral examination and radiography provided the basis for a diagnosis of dilaceration of the maxillary central incisors. After surgical exposure of the impacted teeth, a button with an attached chain was applied to the palatal surface of teeth 11 and 21. After 8 mo, a button was bonded to the labial surface of the crown to fix an elastic chain and move the teeth toward the maxillary arch. Finally, a fixed appliance was applied to tooth alignment to Class 1 malocclusion using a 0.019 × 0.025-inch nickel-titanium wire. After 3 years of follow-up, the clinical findings and radiographic assessment showed that the roots had developed with vital dental pulp and healthy periodontium, were acceptable aesthetically, and showed no resorption.

CONCLUSION

The rare occurrences of dilacerated bilateral maxillary central incisors can be successfully treated through surgical exposure and orthodontics.

Retrospective evaluation of traction time for impacted dilacerated maxillary central incisors in mixed dentition

PURPOSES

This study aimed to contribute to understanding the factors affecting the time of traction treatment of impacted dilacerated maxillary central incisors.

METHODS

This retrospective study included children aged 8 - 11 years with a history of trauma, who applied to the pediatric dentistry clinics of Marmara University, School of Dentistry, between December 2013 and December 2019, and were treated for unilateral impacted dilacerated maxillary upper central incisors. Children's age, sex, digital panoramic radiographs, cone-beam computed tomography, and intraoral photographs were retrieved from electronic dental health records. The effects of children's age, sex, the direction of impacted teeth, distance of the teeth to the top of the alveolar crest, and root dilaceration level on traction time were analyzed by Mann-Whitney U test and Spearman's rank correlation coefficient test.

RESULTS

The inverse position of the incisors significantly increased the traction time (P = 0.012). However, the traction time did not differ according to the sex of the children (P = 0.707) or the level of root dilaceration (P = 0.429). No correlation was observed between the traction time and the age of children (P = 0.644) or the distance of the incisors from the top of the alveolar crest (P = 0.397).

CONCLUSIONS

In cases of the forced eruption of for the impacted dilacerated maxillary central incisors, the direction of the teeth should be evaluated when deciding on the treatment plan, as it may affect the treatment time.

Efficacy of a four-curvature auxiliary arch at preventing maxillary central incisor linguoclination during orthodontic treatment: a finite element analysis

BACKGROUND

Correct torque of the incisors is beneficial in the assessment of the effects of orthodontic treatment. However, evaluating this process effectively remains a challenge. Improper anterior teeth torque angle can cause bone fenestrations and exposure of the root surface.

METHODS

A three-dimensional finite element model of the maxillary incisor torque controlled by a homemade four-curvature auxiliary arch was established. The four-curvature auxiliary arch placed on the maxillary incisors was divided into four different state groups, among which 2 groups had tooth extraction space retracted traction force set to 1.15 N. Initial displacements and pressure stresses of the periodontal tissue in the maxillary incisors and molars were calculated after torque forces (0.5, 1, 1.5, and 2 N) were applied to the teeth at different stable states.

RESULTS

The effect of using the four-curvature auxiliary arch on the incisors was significant but did not affect the position of the molars. Given the absence of tooth extraction space, when the four-curvature auxiliary arch was used in conjunction with absolute anchorage, the recommended force value was < 1.5 N. In the other 3 groups (i.e., molar ligation, molar retraction, and microimplant retraction groups), the recommended force value was < 1 N. The application of a four-curvature auxiliary arch did not influence the molar periodontal and displacement.

CONCLUSION

A four-curvature auxiliary arch may treat severely upright anterior teeth and correct cortical fenestrations of the bone and root surface exposure.

The effect of the root dilaceration on the treatment duration and prognosis of unilateral impacted immature maxillary central incisors

INTRODUCTION

This study aimed to investigate the effect of root dilaceration on the closed-eruption technique treatment and prognosis on impacted immature maxillary central incisors.

METHODS

In this retrospective study, we compared the age at the beginning of the treatment, the treatment duration, root development, and alveolar bone mass after the closed-eruption technique between the impacted immature maxillary central incisors with dilacerated roots (group 1) and those with straight roots (group 2).

RESULTS

The mean age at the time of the surgery of group 1 was 0.9 years younger than that of group 2 (P = 0.008). The mean traction time was greater in group 1 (8.0 ± 1.8 months), with a difference of 1.4 months than in group 2 (6.6 ± 2.1 months) (P = 0.042). The measurements of lingual bone thickness at the alveolar crest (C) showed significant differences between the 2 groups (P = 0.025). No significant differences were found in other treatment duration or measurements of root development and alveolar bone mass between the 2 groups.

CONCLUSIONS

Patients with impacted immature incisors with dilacerated roots were younger at the beginning of the closed-eruption treatment and had a longer traction time than those with impacted immature incisors having straight roots. The root dilaceration had little or no effect on root development and alveolar bone mass after the closed-eruption treatment. The closed-eruption treatment of impacted immature incisors with root dilaceration is suggested to commence as early as possible.

The position and morphology characteristics of multiple impacted anterior teeth in the unilateral maxillary area: A retrospective study based on cone-beam computed tomography

INTRODUCTION

This study investigated the position and morphologic characteristics of multiple impacted anterior teeth in the unilateral maxillary area.

METHODS

Cone-beam computed tomography images of 21 patients (11 males and 10 females; median age 9.42 years [9.08-11.29]) with multiple teeth impacted were collected and imported into Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif). The vertical height, crown orientation, twist direction, and root curvature of each impacted tooth were described. The crown length, root length, and root canal width of impacted and homonym teeth were measured.

RESULTS

The positions of the impacted lateral incisors are lower than that of the other 2 anterior teeth. Most crowns of impacted central incisors are positioned distally, labial surfaces in mesial torsion, with most roots, bent toward the distal and labial. Crowns of impacted lateral incisors are positioned mesiolabially, with labial surfaces mostly in distal torsion, and most roots bent toward the mesial and labial. Crowns of impacted canines are mostly positioned mesiolabially, with labial surfaces in mesial torsion. The crowns and roots of the impacted central and lateral incisors were shorter than those of the homonym (P <0.05); however, the difference in crown length is clinically negligible, and there was no difference in root canal widths. There was no difference in the comparison of parameters for the canine group.

CONCLUSIONS

There are certain rules in the vertical height, crown orientation, twist direction, and root curvature of multiple impacted anterior teeth in the unilateral maxillary area. Root development of impacted central and lateral incisors was restricted.

An analysis of clinical and imaging features of unilateral impacted maxillary central incisors: A cross-sectional study

INTRODUCTION

This cross-sectional study sought to assess clinical features and 3-dimensional distribution of unilateral impacted maxillary central incisors and identify factors associated with the root morphology.

METHODS

Cone-beam computed tomography (CBCT) images from 94 subjects exhibiting unilateral impacted maxillary incisors were selected and evaluated. Original CBCT data were reconstructed using Mimics software (version 17.0; Materialise, Belgium). Clinical features and 3-dimensional distribution of impacted maxillary central incisors and factors associated with the root morphology were observed and analyzed by 2 orthodontists.

RESULTS

This patient cohort included 52 male patients and 42 female patients. Thirty-three incisors (35.11%) with dilacerated roots, 17 incisors (18.09%) with retained deciduous teeth, 15 incisors (15.96%) with supernumerary teeth, and 15 incisors (15.96%) with a history of trauma were identified in the study. Of the 94 impacted incisors, the most common were labially impacted (n = 65; 69.15%), followed by vertically impacted (n = 17; 18.09%) and palatally impacted (n = 12; 12.77%). Chi-square tests revealed that differences in subjects with supernumerary teeth, buccolingual position, sagittal position, and axial position in the upright and dilacerated root groups were statistically significant (P <0.05). Logistic regression analysis indicated that the incidence of dilacerations was higher in the inverted position than in the inclined position and horizontal position (P <0.05).

CONCLUSIONS

Labially impacted maxillary incisors were more common than vertically or palatally incisors. Dilaceration was most commonly observed in patients with inverted incisors. In clinical practice, CBCT is a valuable tool for diagnosing impacted maxillary central incisors and for making appropriate treatment plans for patients.

Post-Treatment Status of Impacted Maxillary Central Incisors following Surgical-Orthodontic Treatment: A Systematic Review

Background and Objectives: The aim of this systematic review was to summarize currently available data of published articles that have investigated the post-treatment status of impacted maxillary central incisors (ICI) treated by the surgical-orthodontic approach. Materials and Methods: MEDLINE, Scopus, Cochrane Oral Health Group’s Trials Register, and ScienceDirect electronic databases were systematically searched with no publication date restrictions up to January 2021. Data assessing the status of ICI after combined surgical-orthodontic treatment and forced eruption duration were extracted, and the quality of the studies was evaluated. Results: In total, 7074 studies were identified, of which 42 articles were assessed for eligibility through full-text evaluation. Seven included studies (five retrospective studies, one randomized clinical trial, and one prospective clinical trial) met the inclusion criteria, representing 211 patients with unilaterally impacted maxillary incisors. The risk of bias ranged from moderate to high. The results show that the root length of immature ICIs increased significantly but remained shorter than that of homonym teeth at post-treatment. Periodontal parameters of treated ICIs were in a clinically acceptable range. Measurements of the alveolar bone showed a reduction of bone thickness and support. The average forced eruption duration ranged from 8.0 ± 4.5 to 14.41 ± 4.03 months. Conclusions: Based on existing evidence, it is reasonable to conclude that the surgical-orthodontic treatment affected the post-treatment status of ICI; however, the current literature is insufficient to draw concrete conclusions. Further well-conducted multi-center randomized studies with a large sample are needed to confirm this statement.

Periodontal implications of surgical-orthodontic treatment of an impacted dilacerated maxillary incisor: A case report with a 2-year follow-up

The treatment of an 8-year-old girl with a dilacerated maxillary incisor began in the mixed dentition; a modified palatal arch attached to the molars served as anchorage for the forced eruption of the dilacerated tooth to prevent the intrusion of the adjacent teeth and reduce the risk of root resorption. Two surgical sessions were planned: the first to permit the closed eruption; the second was an apically positioned flap to add attached gingiva to the labial side of the erupting tooth. The result was an optimal periodontal outcome; moreover, the roots of the adjacent teeth did not show any sign of resorption at the end of the forced eruption. The tooth was vital at the end of the treatment, and the apex covered by alveolar mucosa. The root developed normally throughout the treatment, and the periodontium was healthy and esthetically acceptable at the 2-year follow-up. Further study is needed to assess the advantages of the combined surgical-orthodontic treatment.