Alveolar bone retention following treatment of dilacerated labial inversely impacted maxillary central incisors-a retrospective study.

The root of late-dental-age labial inversely impacted maxillary central incisors (LIIMCIs) typically develops to severe dilacerated morphology. Therefore, reliable posttreatment periodontal estimates of orthodontic treatment prognosis would be critical to the treatment value of impacted incisors. This study aims to analyze further changes in dimensions of the alveolar bone following the closed-eruption treatment of late-dental-age dilacerated LIIMCIs. Cone beam computed tomography (CBCT) scanning data of 16 patients with unilateral dilacerated late-dental-age LIIMCIs were collected, including the pretreatment (T1) and at the 2.23 ± 0.78 years follow-up stage (T2) respectively. Patients underwent closed-eruption treatments to bring the impacted incisor into the dental arch. Dolphin imaging software was used to measure alveolar bone height labially, palatally, and proximally to the site at T1 and T2, as well as alveolar bone thicknesses at 0, 2, 4, 6 and 8 mm below the initial measurement plane (IMP). The alveolar bone heights on the impacted and contralateral sides increased from T1 to T2 (p < 0.05). Alveolar bone growth on both sides had no significant difference. In T2, the mean values of labial and distal alveolar heights on the contralateral sides were greater than on the impacted sides (p < 0.05). The mean values of total alveolar bone thicknesses on the impacted sides in T1 were significantly smaller than those on the contralateral sides in IMP-0, 2, 4, 6, 8 (p < 0.05). The total thicknesses on the impacted sides in T2 increased and were significantly greater than on the contralateral sides (p < 0.05), except for the thickness in IMP-0. The closed-eruption treatment of dilacerated late-dental-age LIIMCIs results in no significant changes to alveolar bone height, except on the labial and distal sides, with increased alveolar bone thickness, suggesting that this approach may be viable first choice therapy for non-extraction orthodontic cases.

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 (ß = -0.237; P = 0.008), the labiopalatal distance from the transposed canine to the apex of the lateral incisor (ß = 0.675; P <0.001), and the inclination of the transposed lateral incisor (ß = 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.

Morphometric evaluation of alveolar bone after orthodontic treatment of multiple impacted teeth in the unilateral maxillary anterior region.

INTRODUCTION: This study aimed to investigate the height and thickness of alveolar bone by cone-beam computed tomography imaging after orthodontic treatment in the unilateral maxillary anterior region and speculate on reasons for the difference in alveolar bone morphology. METHODS: This study selected 11 patients (3 males and 8 females; mean age, 9.42 ± 1.45 years). Cone-beam computed tomography was performed for these 11 patients before and after treatment using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif). Labial and palatal alveolar bone thickness (BT) at root apices and different levels along the roots and loss of alveolar bone height was measured for each impacted tooth and its contralateral homonymous tooth. RESULTS: After orthodontic therapy, all 3 impacted anterior teeth had different degrees of loss of labial alveolar bone height compared with the normal side (central incisor: -1.5 mm, P <0.005; lateral incisor: -1.06 mm, P <0.01; canine: -0.59 mm, P < 0.01). The lateral incisors also showed palatal alveolar bone height loss compared with the unaffected side (-0.8 mm, P <0.005). Alveolar BT at root apices of impacted canines was 1.14 mm thicker than the normal side (P <0.005). Central and lateral incisors were similar to the normal side. The thickness of the alveolar bone at 8, 10, and 12 mm of the impacted canine position was still larger than that on the healthy side, whereas the difference in average thickness between the healthy and affected side had been significantly reduced compared with pretreatment measurements. CONCLUSIONS: There is satisfactory retention of alveolar bone height in canines after orthodontic treatment; however, alveolar bone loss is slightly worse at central and lateral incisors. Retention of alveolar BT was normal for impacted anterior teeth, whereas excess apical alveolar BT at the canines, although still present, was substantially less significant than had been observed before treatment.

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.

The differences of root morphology and root length between different types of impacted maxillary central incisors: A retrospective cone-beam computed tomography study.

INTRODUCTION: The purpose of this trial was to use 3-dimensional data to analyze the differences of root morphology and root length between 3 different types of impacted maxillary central incisors. METHODS: Cone-beam computed tomography images of 126 patients with impacted maxillary central incisors were included in this retrospective study. On the basis of the angle of the impacted incisor to the palatal plane, we categorized the tooth as labial inversely impacted, labially positioned, or palatal impacted incisor. In each category, the early and late dental age groups were classified according to the method of Nolla. The total root length of both impacted and homonym teeth, length of the nondilacerated part of the root, length of the dilacerated part of the root, the angle between the crown and root, and root direction, were measured in the sagittal-view sections using Dolphin Imaging software (version 11.9; Dolphin Imaging and Management Solutions, Chatsworth, Calif). RESULTS: Compared with the early dental age groups, the length of the dilacerated portion of the root and rate of dilaceration for inverse labial and labially positioned impactions increases, and crown-root angle decreases (P <0.05). The dilacerated part of the root bent labially, and the root morphology shows an obvious L-shaped curve. The length of the nondilacerated part of the root for palatal impactions is greater(P <0.05). The dilacerated part of the root bends palatally, and the root morphology shows a continuous C-shaped curve. CONCLUSIONS: Obstruction from the alveolar bone will cause different root morphology. Root morphology of labial impactions shows an obvious L-shaped curve; palatal impactions show a continuous C-shaped curve.

Association between palatally displaced maxillary central incisors and lateral incisors: A retrospective cone-beam computed tomographic study.

INTRODUCTION: The objective of this study was to investigate the location, orientation and root development of maxillary lateral incisors in patients with palatally impacted central incisors. Comparison was made between the lateral incisor on the affected side and that on the normally erupted side. METHODS: Cone-beam computed tomographic images from 20 patients (10 boys, 10 girls, mean age (9.01 ± 1.52 years old) with unilateral palatally impacted maxillary central incisors were imported into Dolphin imaging software 11.8 for 3-dimensional reconstruction and reorientation. Software measurement tools were used to measure the root length, crown distance, angle to palatal plane, distance to midline, and angle to midsagittal plane of the maxillary lateral incisors on both the impacted and unaffected sides. RESULTS: The Wilcoxon signed rank test indicated that lateral incisors on the impacted side were more proclined, at a mean angle difference of 29.47° in the sagittal plane (P < 0.001). The mean length of the roots of the lateral incisors was 1.21 mm shorter (P < 0.05) on the affected side compared with the normal side, and the lateral incisor crowns on the impacted side were located at an average of 4.57 mm closer to the palatal plane than on the normally erupted side (P < 0.001). The angle of long axis of the lateral incisors on the affected side had a greater angulation to the midsagittal plane compared with the unaffected side, with a mean difference of 30.27° (P < 0.001). CONCLUSIONS: Maxillary lateral incisors adjacent to palatally impacted maxillary central incisors side had abnormal root development and demonstrated angulation and position change compared with those adjacent to normally erupted central incisors.

The impact of orthodontic treatment on the quality of life a systematic review.

BACKGROUND: Although a great number of specific quality of life measures have been developed to analyze the impact of wearing fixed appliances, there is still a paucity of systematic appraisal of the consequences of orthodontics on quality of life. To assess the current evidence of the relationship between orthodontic treatment and quality of life. METHODS: Four electronic databases were searched for articles concerning the impact of orthodontic treatment on quality of life published between January 1960 and December 2013. Electronic searches were supplemented by manual searches and reference linkages. Eligible literature was reviewed and assessed by methodologic quality as well as by analytic results. RESULTS: From 204 reviewed articles, 11 met the inclusion criteria and used standardized health related quality of life and orthodontic assessment measures. The majority of studies (7/11) were conducted among child/adolescent populations. Eight of the papers were categorized as level 1 or 2 evidence based on the criteria of the Oxford Centre for Evidence-Based Medicine. An observed association between quality of life and orthodontic treatment was generally detected irrespective of how they were assessed. However, the strength of the association could be described as modest at best. Key findings and future research considerations are described in the review. CONCLUSIONS: Findings of this review suggest that there is an association (albeit modest) between orthodontic treatment and quality of life. There is a need for further studies of their relationship, particularly studies that employ standardized assessment methods so that outcomes are uniform and thus amenable to meta-analysis.