Clinical Outcomes of 0.018-Inch and 0.022-Inch Bracket Slot Using the ABO Objective Grading System

Objective: To determine if there is a significant difference in the clinical outcomes of cases treated with 0.018-inch brackets vs 0.022-inch brackets according to the American Board of Orthodontics (ABO) Objective Grading System (OGS). Materials and Methods: Treatment time and the ABO-OGS standards in alignment/rotations, marginal ridges, buccolingual inclination, overjet, occlusal relationships, occlusal contacts, interproximal contacts, and root angulations were used to compare clinical outcomes between a series of 828 consecutively completed orthodontic cases (2005–2008) treated in a university graduate orthodontic clinic with 0.018-inch- and 0.022-inch-slot brackets. Results: A two-sample t-test showed a significantly shorter treatment time and lower ABO-OGS score in four categories (alignment/rotations, marginal ridges, overjet, and root angulations), as well as lower total ABO-OGS total score, with the 0.018-inch brackets. The ANCOVA—adjusting for covariants of discrepancy index, age, gender, and treatment time—showed that the 0.018-inch brackets scored significantly lower than the 0.022-inch brackets in both the alignment/rotations category and total ABO-OGS score. Conclusions: There were statistically, but not clinically, significant differences in treatment times and in total ABO-OGS scores in favor of 0.018-inch brackets as compared with the 0.022-inch brackets in a university graduate orthodontic clinic (2005–2008)

Reliability and Validity of the OrthoMechanics Sequential Analyzer

poster abstractPurpose: The aim of this study was to evaluate the reliability and validity of newly developed software in the assessment of orthodontic tooth movement three dimensionally. Methods: The sample consisted of pre- and post- treatment computed tomography scans and plaster dental models of 20 orthodontic subjects treated with a hyrax expander as a part of their comprehensive orthodontic treatment. Dental arch measurements, including arch widths, tooth inclinations and angulations, were measured on the scans using InvivoDental 3D imaging software version 5.1. The plaster dental models were laser scanned, superimposed, and measurements were obtained digitally using the new software. Agreement between the digital models and the CT measurements was evaluated using intraclass correlation coefficients (ICCs), paired t-tests, and Bland-Altman plots. A p-value of ≤ 0.05 was considered statistically significant. Results: High agreement (ICC > 0.9), a non-significant paired t-test, and no indication of agreement discrepancies were observed for most of the measured parameters. Conclusions: The new software program offers a valid and reliable tool concerning dental arch measurements obtained from 3D laser scanned models. It could be considered a possible practical method that helps the orthodontist evaluate the treatment progress in a non-invasive manner and without unnecessary radiation exposure. Funding: Indiana University Purdue University - Office of the Vice Chancellor for Research & the Funding Opportunities for Research Commercialization and Economics Success (FORCES)

Effects of mandibular advancement appliances on the upper airway dimensions

poster abstractPurpose: The aim of this retrospective cephalometric study was to investigate dentoskeletal and airway dimensional changes in a group of orthodontic patients with deficient mandible using Herbst vs. MARA appliances. Methods: Pre-treatment and post-treatment lateral cephalometric radiographs of 34 subjects with deficient mandible (aged 9-22 years) were selected from the postgraduate orthodontic clinic archives. The cephalograms were classified into 2 groups . Group 1 (n=17) consisted of cephalograms from individuals treated with a Herbst appliance and group 2 (n=17) consisted of cephalograms from individuals treated with a MARA appliance. Each cephalogram was traced manually and the selected dentoskeletal and airway parameters were recorded for all subjects. Intraclass correlations (ICC) were performed on duplicate measures of 10 cephalograms to assess reliability. Paired t-tests were used to differences in the airway parameters from pre-treatment to post-treatment within groups. Statistical significance was set at P < 0.05. Results: ICC values were ˃0.90 for all measurements. Significant changes were recorded in ANB, N-S, ANS-PNS, Go-Gn, Overbite, Overjet, Co-ANS, Co-Gn, TFH, AFH, and LAFH for both Herbst and MARA groups. Airway parameters such as soft tissue thickness of the posterior pharyngeal wall (Ba-ad1 and Ba-ad2), anteroposterior dimension of bony nasopharynx (Ba-PNS, AA-PNS and AA-ptm), and width of the nasopharyngeal airway space (PNS-ppw1) showed statistically significant decreases in both groups. The Herbst group also showed statistically significant decrease in the sagittal depth of pharyngeal lumen at the nasopharynx and oropharynx (ptm-ad1, PNS-ad1, and PNS-ppw2) while the MARA group demonstrated a statistically significant decrease in the angle represents the anteroposterior dimension of the nasopharynx (AA-S-PNS). Conclusion: Using mandibular advancement appliance decrease significantly the upper airway dimensions. The amount of the change in the upper airway size was variable between Herbst and MARA appliances

The Effect of Anterior Tooth Position on Trumpet Performance Quality

poster abstractObjective: Music teachers contend that the arrangement of anterior teeth affects trumpet performance by influencing the embouchure. Since there is little quantitative data to support this claim, the purpose of this study was to determine whether trumpet performance skills are associated with the malalignment of anterior teeth. Methods: Following IRB approval, 70 trumpet students (55M:15F; aged 20-38.9 yrs.) from 11 universities were consented to complete a survey concerning dental history and trumpet playing habits. The students were asked to play a scripted performance skill test (flexibility, range, endurance, and articulation exercises) on their instrument in a soundproof music practice room while being audio and video recorded. A threedimensional (3D) cone beam computerized tomograph (CBCT) was taken of each student the same day as the skill test. Following reliability studies, overjet, overbite, and degree of anterior tooth irregularity (Little’s Index) were measured on the 3D CBCT. Nonparametric correlations, accepting p0.8). Significant (p<0.05), but weak (r<0.30) associations were found only between Little’s Index of the mandibular anterior dentition and the performance skills: flexibility (exercises a, c and avg) and articulation (double tongue). No other associations were significant. Conclusions: University trumpet students with mandibular anterior teeth that are smoothly aligned have significantly better performance skills than those with misaligned mandibular anterior teeth; however, the association is weak

Orthodontic Soft Tissue Parameters: A Comparison of CBCT and 3dMD

poster abstractObjectives: Orthodontists rely heavily on soft tissue analysis to determine esthetics and treatment stability. Although the reliability of three dimensional photography (3dMD) and cone beam computed tomography (CBCT) is established, little data exists comparing the soft tissue measurements between these two imaging modalities. The aim of this retrospective study is to compare the equivalence of soft tissue measurements between the 3dMD imaging system and the segmented skin surface derived from i-CAT CBCT. Methods: Seventy preexisting 3dMD extraoral photographs and CBCT scans taken within minutes of each other for the same subjects were superimposed using 3dMD Vultus software on soft tissue. Images were registered according to hard tissue planes in three dimensions. Following reliability studies, 28 soft tissue measurements were selected and recorded on both imaging modalities. The measures were then compared between the two images to analyze their equivalence. Intraclass correlation coefficients (all ICCs >.8) and Bland-Altman plots were used to assess the inter- / intra-examiner repeatability and agreement. Summary statistics were calculated for all measurements. To demonstrate equivalence of the two methods, the difference needed a 95% confidence interval contained entirely within the equivalence limits defined by repeatability results (twice the within-subject standard deviation of CBCT). Results: Statistically significant differences were reported for the following measurements: vermilion height (Ls-Li), mouth width (CH[R]–CH[L]), total facial width (Tr[R] – Tr[L]), mouth symmetry (Ch[R] to Sup. Facial Plane), ST Lip Thickness (LI to mand CI), and eye symmetry (Exoc R & L to Sup. Facial Plane). Conclusions: There are areas of non-equivalence between the two imaging methods. Differences are clinically acceptable from the orthodontic point of view

A Three-Dimensional Analysis of Maxillary Sinus Congestion in Unilateral Cleft Lip and Palate

Cleft lip and palate (CLP) perturbs osseous and soft-tissue development of the nasolabial regions, often resulting in chronic maxillary sinusitis and mucosal thickening (MT) of the maxillary sinus. This preliminary study quantifies maxillary sinus MT in children with surgically repaired unilateral CLP. We hypothesize that maxillary sinus MT is increased in children with CLP relative to controls. We define "MT" as the difference between the entire maxillary sinus volume and airspace volume. Cone beam computed tomography (CBCT) images of 8-14 yr. old age- and sex-matched unilateral CLP patients (n = 10) and controls (n = 10) were obtained (IRB approval # 1210009813). Both maxillary sinus and airspace surface areas (SAs) were measured on each individual CBCT slice in coronal view. SA measurements were summed and multiplied by voxel size (0.4mm) to obtain a volume. Paired t-tests determined whether maxillary sinus volume, air volume, MT (i.e. maxillary sinus volume – airspace volume), and percentage of MT (i.e. MT/maxillary size x 100) differed. A p-value of ≤ 0.05 was considered significant. Intra-class correlation assessed reliability and was high (0.99). Significant differences were found for several measurements: Maxillary airspace (non-cleft side vs. right side control p-value = 0.002; cleft-side vs. left side control p-value = 0.004), MT (cleft-side vs. left side p-value = 0.009), and percentage of MT (non-cleft side vs. right side control p-value = 0.002, cleft-side vs. left side control p-value = 0.002). Maxillary airspace was decreased by 30% (non-cleft side) and by 33% (cleft side). Percentage of average MT was 40% (non-cleft side) and 42% (cleft side) of CLP patients, but only 9% (left and right side) in controls. Surgically repaired CLP patients exhibit decreased maxillary airspace and increased MT relative to controls. CLP deformities are associated with MT. 3D imaging is useful for quantitatively evaluating MT of the maxillary sinus

Airway dimensions and pathologies of trumpet players vs. non-trumpet players.

Objective: The objective of this retrospective, 3-dimensional cone beam computed tomography study was to determine if there is a significant difference between the most constricted area of the airway, the prevertebral soft tissue thickness and airway dimensions (length and volume) of the nasal cavity, nasopharynx, oropharynx, and maxillary sinuses of university trumpet players versus non-trumpet playing controls. The second objective was to determine significant differences in the prevalence of airway pathologies between university trumpet players and controls. Method: Following IRB approval and consent and reliability studies, measurements of airway parameters and pathology were compared between 66 Caucasian trumpeters and 22 ethnicmatched controls. An analysis of covariance, with age and sex included as covariates, was used to compare the airway measures. Since there was a significant difference in gender and age, comparisons between groups for the presence of any airway pathologies was made using logistic regression including age and sex as covariates. A 5% significance level was used for all comparisons. Result: The trumpet players had significantly smaller nasal cavity volume (18028 + 595 mm3 vs. 25266 + 1116 mm3; p<0.0001) and significantly greater soft tissue thickness at CV2ia (3.29 + 0.10 mm vs 2.70 + 0.10 mm; p=0.03) and CV3sa (4.55 + 0.13 mm vs 3.74 + 0.14 mm; p=0.005) than the controls. No other airway measure demonstrated a significant difference between the two groups. Trumpeters had significantly (p=0.002) more airway pathology (n=33; 50%) than the controls (n=4; 18%). Antral pseudocysts or polyps composed 52% of trumpeter pathologies as compared with 0% controls. Conclusion: The only significant differences in airway dimensions between trumpet players and controls were decreased nasal cavity volume and some areas of prevertebral soft tissue thickness. Trumpeters were almost three times as likely to exhibit airway pathology when compared with controls. Funding: IUPUI Signature Center Initiative – 3D Imaging of the Craniofacial Complex Center and the Joseph and Aida Jarabak Endowed Professorship

Comparison of movement rate with different initial moment-to-force ratios

Introduction: The objective of this clinical prospective study was to evaluate the effect of the two treatment strategies, translation or controlled tipping followed by root correction, on canine retraction efficiency, specifically canine movement rate. Methods: Twenty-one patients who needed bilateral maxillary canine retraction to close extraction space as part of their treatment plan were selected for this study. Segmental T-loops designed for controlled tipping or for translation were applied randomly to each side. Two digital maxillary dental casts (taken pre- and post-treatment) were used to measure the tooth displacements of each patient. The coordinate system located at the center of canine crown on the pre-treatment model with the three axes defined in the mesial-distal (M-D), buccal-lingual (B-L), and occlusal-gingival (O-G) directions was used to express the six tooth displacement components. The movement rates on the occlusal plane and in the M-D direction were computed. Movement rates were calculated by dividing the M-D displacements or the resultant displacement on the occlusal plane with the corresponding treatment time. Results: T-loops for controlled tipping moved canines faster (33.3% on occlusal plane and 38.5% in the M-D direction) than T-loops for translation. The differences are statistically significant (p = 0.041 on the occlusal plane and 0.020 in the M-D direction). Conclusion: 1. Moment-to-force ratio (M/F) impacts on the canine movement rate in a maxillary canine retraction treatment with segmented T-loop mechanism. 2. Within the neighborhood of the ratio for translation, lower M/F moves canine faster than higher M/F both on occlusal plane and in the M-D direction

3D Assessment of Nasopharyngeal and Craniofacial Phenotypes in Ts65Dn Down Syndrome Mice Treated with a Dyrk1a Inhibitor

Background: Down syndrome (DS) originates from having three copies of chromosome 21 (i.e. Trisomy 21). DS is associated with many detrimental phenotypes including intellectual disabilities, heart defects, abnormal craniofacial development, and obstructive sleep apnea, which develops from restricted nasopharyngeal airways and an underdeveloped mandible. Ts65Dn mice are trisomic for about half of the orthologs on human chromosome 21 and display many phenotypes associated with DS including craniofacial abnormalities. Dyrk1a is found in three copies in Ts65Dn mice and individuals with DS, and thought to be a root cause of the craniofacial phenotypes. Epigallocatechin 3-gallate (EGCG) is a green tea polyphenol and inhibitor of Dyrk1a activity. Purpose: We hypothesize that decreased Dyrk1a activity in Ts65Dn mice will ameliorate craniofacial dysmorphology. Methods: To test our hypothesis we compared Ts65Dn mice with two or three copies of Dyrk1a and compared Ts65Dn mice with and without prenatal EGCG treatment. EGCG treated mothers were fed 200mg/kg EGCG on gestational day 7. Six week old mice were sacrificed and their heads imaged using micro-computed tomography (μCT). From μCT images, we measured nasopharyngeal airway volume and anatomical landmarks (n = 54) from the facial skeleton, cranial vault, cranial base, and mandible. Mean nasopharyngeal airway volumes were graphically compared, and a landmark-based multivariate geometric morphometric approach known as Euclidean Distance Matrix Analysis (EDMA) was carried out to assess local differences in craniofacial morphology between trisomic mouse samples. Results: Our preliminary results indicate that EGCG treatment and reduced Dyrk1a copy number increases mean nasopharyngeal airway volume in Ts65Dn mice. Craniofacial morphometric differences were found among all samples. EGCG treatment increased portions of the mandible and decreased portions of the cranial vault and cranial base. Conclusion: Preliminary analyses suggest that both EGCG treatment and reduced Dyrk1a copy number affect craniofacial morphology.Three Dimensional Imaging of the Craniofacial Complex Center (3D ICCC)--IUPUI Signature Center Initiative

Hounsfield unit change in root and alveolar bone during canine retraction

INTRODUCTION: The objective of this study was to determine the Hounsfield unit (HU) changes in the alveolar bone and root surfaces during controlled canine retractions. METHODS: Eighteen maxillary canine retraction patients were selected for this split-mouth design clinical trial. The canines in each patient were randomly assigned to receive either translation or controlled tipping treatment. Pretreatment and posttreatment cone-beam computed tomography scans of each patient were used to determine tooth movement direction and HU changes. The alveolar bone and root surface were divided into 108 divisions, respectively. The HUs in each division were measured. Mixed-model analysis of variance was applied to test the HU change distribution at the P <0.05 significance level. RESULTS: The HU changes varied with the directions relative to the canine movement. The HU reductions occurred at the root surfaces. Larger reductions occurred in the divisions that were perpendicular to the moving direction. However, HUs decreased in the alveolar bone in the moving direction. The highest HU reduction was at the coronal level. CONCLUSIONS: HU reduction occurs on the root surface in the direction perpendicular to tooth movement and in the alveolar bone in the direction of tooth movement when a canine is retracted