Evaluation of skeletal and dentoalveolar dimensions in patients with maxillary unilateral impacted canine: a cone beam computed tomographic study.

OBJECTIVE: To assess the skeletal and dentoalveolar dimensions of subjects with the unilateral maxillary-impacted canine and compare it with the non-impacted side using cone beam computed tomography (CBCT). METHODS: A split-mouth study that included 26 CBCTs (52 sides) with unilateral impacted canine was designed. The parameters analyzed were alveolar height; bucco palatal width at 2 mm, 6 mm, and 10 mm from alveolar crest; premolar width; lateral angulation of incisors; root length of lateral incisors; and crown-root angulation of lateral incisors. Obtained data were statistically analyzed by unpaired independent t-test. RESULTS: The bucco palatal width at 2 mm and the premolar width from mid-palatal raphe were 1.22 mm and 1.71 mm less on the impacted side, respectively; the central and lateral incisor angulations were less by 3.69 degrees and 3.40 degrees, respectively, on the impacted side; the lateral incisor root length was 2.8 mm shorter on the impacted side; the crown-root angulation for lateral incisor was 2.4 degrees more on the impacted side. CONCLUSION: The following conclusions can be drawn: (1) The premolar width is less on the impacted side. (2) The incisors are more distally angulated on the impacted side. (3) The crown-root angulation of the lateral incisor is mesially directed on the impacted side. CLINICAL RELEVANCE: Asymmetric arch expansions should be undertaken in severe transverse asymmetries. In the beginning stages of treatment, the arch alignment, excluding incisors, must be undertaken to safeguard the roots of incisors.

Learning Cephalometric Landmarks for Diagnostic Features Using Regression Trees.

Lateral cephalograms provide important information regarding dental, skeletal, and soft-tissue parameters that are critical for orthodontic diagnosis and treatment planning. Several machine learning methods have previously been used for the automated localization of diagnostically relevant landmarks on lateral cephalograms. In this study, we applied an ensemble of regression trees to solve this problem. We found that despite the limited size of manually labeled images, we can improve the performance of landmark detection by augmenting the training set using a battery of simple image transforms. We further demonstrated the calculation of second-order features encoding the relative locations of landmarks, which are diagnostically more important than individual landmarks.

Skeletal and dentoalveolar contributions during Class II correction with Forsus™ FRD appliances : Quantitative evaluation.

PURPOSE: Primary objective of the study is to quantify and evaluate the skeletal and dental contributions during sagittal Class II correction with the Forsus™ fatigue resistant device (FRD; 3M Unitek Corp., Monrovia, CA, USA). Secondary objective is to evaluate the overall vertical, soft tissue and chin-throat relation changes with the Forsus™ appliance. PATIENTS AND METHODS: A retrospective sample of 27 Class II patients treated with the Forsus™ FRD appliance was compared to 20 untreated control subjects who were matched according to age and craniofacial morphology. Pre-Forsus™ (T0) and Post-Forsus™ (T1) cephalograms were subjected to composite cephalometric analysis. Growth changes were subtracted from the treatment changes to obtain the treatment effects of the appliance. The data were analyzed using Student's t­test and independent t test. RESULTS: Significant differences were found between the treated and the control group in 16 of 29 measured variables. The overjet and molar relation improved by 4.23 mm and 4.49 mm, respectively. This was mainly achieved by backward movement of maxillary incisors (1.4 mm) and molars (1.22 mm) and forward movement of mandibular incisors (2.26 mm) and molars (2.70 mm). Overbite decreased by 2.24 mm with no changes in mandibular and nasal plane angles. CONCLUSION: The Forsus™ FRD was effective in correcting Class II malocclusion mainly at the dentoalveolar level. The net skeletal and dentoalveolar contributions towards both overjet and molar correction was 13% and 87%, respectively. The improvement in soft tissue profile and chin-throat configuration was statistically insignificant.

Mini-implant and Modified Nance Button Assisted Alignment of a Horizontally Impacted Maxillary Canine - A Case Report.

Orthodontic alignment of a horizontally impacted canine placed high and deep in the maxilla represents a challenging clinical scenario. This article describes a case report of a 16-year-old postpubertal male patient who was concerned about an unesthetic smile. The clinical and radiographic investigations revealed that the patient had retained deciduous canines and bilaterally impacted maxillary canines. The right impacted canine had a good prognosis. The left canine was horizontally impacted in the labial side with a Kau-Pan-Gallerano index score of 19, which indicates a "difficult" degree of treatment. The initial treatment plan was application of distal traction to the impacted left canine from reinforced anchorage unit to change its inclination from horizontal to vertical before erupting it toward occlusion. In this case report, we demonstrated the use of a mini-implant and a modified Nance button-assisted forced eruption of an impacted canine. The 12-month follow-up review showed that the results were maintained during the time, and the previously impacted teeth showed intact gingival attachments. A conservative surgical exposure of the impacted canine and well-planned biomechanics helped us achieve a desirable, esthetic outcome.

Evaluation of Root Resorption, Tooth Inclination and Changes in Supporting Bone in Class II Malocclusion Patients Treated with Forsus Appliance.

OBJECTIVE: The aim of our study was to evaluate apical root resorption and changes in tooth inclinations, marginal bone height, and labio-lingual bone thickness at the mid-root and apical level in mandibular anterior teeth during the Forsus treatment using cone beam computed tomography (CBCT). METHODS: CBCT scans of 16 subjects (8 males and 8 females) with Class II malocclusion (age group: 13-29 years) taken before and 6 months after the Forsus treatment were evaluated for apical root resorption, tooth inclination, marginal bone height, and thickness of bone at the mid-root and apical level in mandibular anterior teeth. RESULTS: There was statistically significant root resorption of central incisors (0.39 mm) and canines (0.66 mm); a decrease in the angle of inclination for all teeth; an increase in the marginal bone measurement in labial (1.31 mm) and decrease in lingual (0.93 mm) aspect at the canine region; and an increase in bone width by 0.87 mm and 0.75 mm in central and lateral incisor regions, respectively, at the mid-root level lingually. At the apex level in the canine region, bone width increased by 1.4 mm labially, while it decreased by 2.18 mm lingually; it increased significantly for incisors in the lingual region. CONCLUSION: The Forsus appliance therapy causes clinically insignificant root resorption and bone changes, and clinically significant proclination of mandibular anterior teeth. The findings of the present study aid clinicians in proper case selection and reinforce the prevention of incisor proclination while using the Forsus therapy to achieve better treatment results and stability.

Anchorage Reinforcement Post Molar Distalization.

After distalization of maxillary molars, retaining it in the new position is of utmost importance. There are various methods available to avoid taxing freshly distilized molars. We have discussed various methods to reinforce anchorage post-molar ditalization. We have introduced a new appliance that is a modified Nance palatal button for continuous distally directed force on the molars.

Quick and easy placement of coil spring.

A tooth displaced palatally in an arch often demands placement of an open coil spring for gaining space. Ligation of an archwire with compressed coil spring is a cumbersome process. We have made use of 0.010 supreme AJ Wilcock sectional wire to compress the open coil spring and place it on the required the dental arch.

Quick and Easy Placement of Coil Spring.

A tooth displaced palatally in an arch often demands placement of an open coil spring for gaining space. Ligation of an archwire with compressed coil spring is a cumbersome process. We have made use of 0.010 supreme AJ Wilcock sectional wire to compress the open coil spring and place it on the required dental arch.

Modified transpalatal arch for molar intrusion.

We have modified transpalatal arch (TPA) to intrude the extruded molar. The appliance is fabricated from 0.036 inch stainless steel wire which has a palatal and buccal arm. The appliance is activated by stretching an elastomeric chain from the palatal to the buccal arm such that the stretched chain lies across the occlusal surface of extruded second molar with an intensive force of 50 grams. The advantages of this appliance include reduced chair side time, patient comfort and cost effectiveness.

Rapid canine retraction with periodontal distraction in Class II division 1 malocclusion: a case report.

This case report describes the treatment of an 18-year-old post-pubertal male patient with a class II division 1 malocclusion. Rapid canine retraction was planned after extraction of first premolars in maxillary arch 7 mm of canine retraction was achieved in 19 days with customized periodontal distractor with minimal change (10 degrees) in canine inclination. The maxillary molars were able to withstand the retraction forces with minimal vertical anchor loss (0.5mm). During distraction phase, patient experienced slight discomfort which vanished in 2-3 days. After distraction, anterior teeth retraction was rapid because of fibrous bony tissue distal to the lateral incisor. Orthodontic treatment continued for 12 months with no clinical and radiographic evidence of complications like root fracture, resorption, ankylosis and soft tissue dehiscence. Good overjet and overbite was achieved at the end of treatment with dramatic improvement in facial esthetics. Periodontal distraction is an effective alternative to shorten treatment time eliminating need for additional anchorage.

Stainless hooks to bond lower lingual retainer.

We introduced a simple and economical technique for precise placement of lower lingual retainers. Two stainless steel hooks made of 0.6mm wire are placed interdentally in the embrasure area between canine and lateral incisor bilaterally to lock the retainer wire in the correct position. Etch, rinse and dry the enamel surfaces with the retainer passively in place, then bond the retainer with light-cured adhesive. Hooks are simple to fabricate and eliminate the need for a transfer tray.

The ideal smile and its orthodontic implications.

AIM: To determine the parameters for an ideal smile. METHODS: Ten laypersons classified frontal photographs of 62 smiling individuals between 18 and 25 years of age into five categories: 1, poor; 2, fair; 3, good; 4, very good; and 5, excellent. The scores obtained for each smile were averaged. The five smiles with each the highest and lowest scores were analyzed for seven parameters: buccal corridor, smile index, smile symmetry, smile line ratio, upper lip line, smile arc, and upper lip curvature. RESULTS: The five smiles with the highest scores were symmetrical with an average upper lip line and a consonant smile arc. Three of the five had an upward upper lip curvature. The smile line ratio, buccal corridor, and smile index for all five subjects ranged from 1.0 to 1.3 mm, 9.0% to 11.0%, and 4.0 to 6.0 mm, respectively. Two of the five smiles with the lowest scores were asymmetrical and three had a high upper lip line and a downward curvature, but all five had a nonconsonant smile arc. The smile line ratio, buccal corridor, and smile index for all five subjects ranged from -1.0 to 1.3 mm, 18.0% to 22.0%, and 7.0 to 10.0 mm, respectively. CONCLUSION: The seven investigated smile parameters can define characteristics of an ideal smile. These smile components should be included in the orthodontic problem list to help clinicians select the appropriate mechanotherapy.

Evaluation of Moyers mixed dentition analysis in school children.

BACKGROUND AND OBJECTIVE: The purpose of this study is to test the reliability of Moyers mixed dentition analysis in school children. MATERIALS AND METHODS: A study was conducted on a sample of 150 school children within the age group of 13 to 16 years old who had all permanent teeth that were fully erupted. Dental impressions were taken with alginate impression material and immediately poured with dental stone. Mesiodistal dimensions of permanent mandibular incisors, maxillary and mandibular canines, and premolars were measured using a digital caliper with a resolution of 0.01 mm. STATISTICAL ANALYSIS: The coefficient of correlation (r) was calculated to find the correlation between the sums of the canine, premolars in both arches, and mandibular incisors. A Student's unpaired t test was calculated to compare the tooth dimension between male and female subjects. The actual measurements were compared with the predicted values obtained with the Moyers prediction tables at the 35 th , 50 th , and 75 th percentile confidence levels. A Student's t test was calculated to compare the actual and predicted values. Using this data, linear regression equations were formulated for tooth size prediction. The coefficient of determination [r2] was calculated to find the accuracy of the formulated prediction equations. The standard error of estimate (SEE) was calculated to determine the validity of the proposed equations. RESULTS: Moyers prediction tables are not an accurate method to estimate tooth dimension in our samples. The mesiodistal crown dimension in the buccal segment of the mandibular arch was larger in males (p=0.04) than in females. CONCLUSION: The differences noted between predicted values from the Moyers tables and that of the present investigation is the result of racial and ethnic diversity. The accuracy of the prediction equation should be tested in a larger sample.