Purpose: To evaluate the factors that influence potential orthodontic patients choosing between an orthodontist, general dentist, and direct-to-consumer (DTC) aligners for their treatment, and to determine the demand for each provider type. Methods: An electronic survey was administered to 250 individuals among the general population of adults in the United States. Questions were designed to determine the respondent’s level of interest in pursuing orthodontic treatment with each provider type, evaluate their current level of knowledge concerning provider options, and identify factors influencing their selection. Pearson’s chi-squared test and ANOVA were used to evaluate the factors influencing patients in their selection. Results: When asked their preference in provider type, 43.8% of respondents selected orthodontist, 34.1% selected DTC aligners, and 22.1% selected general dentist. Among respondents with the highest level of interest in pursuing orthodontic treatment, 50% selected an orthodontist and 27% selected DTC aligners. For respondents with moderate levels of interest in pursuing treatment, only 21% selected an orthodontist and 48% selected DTC aligners. The biggest perceived advantage of treatment with an orthodontist was quality of treatment, and the biggest disadvantage was cost. For DTC aligners, the biggest perceived advantage was convenience, followed by cost, and the biggest disadvantage was quality of treatment. Among adults with children, 34% selected DTC aligners for themselves and only 16% selected DTC aligners when selecting for their children. Conclusion: Adults in the United States have similar levels of interest in pursuing orthodontic treatment with orthodontists and DTC aligners and, to a lesser degree, general dentists. A significant portion of those who select DTC aligners for their treatment are patients who would not have otherwise undergone treatment with an orthodontist. Patients tend to select orthodontists due to quality of treatment, whereas DTC aligners are selected due to convenience, followed by cost. Even among parents who prefer DTC aligners for their own treatment, parents tend to select an orthodontist for their child’s treatment.

Aim: To evaluate the ability of a publicly available facial recognition application program interface (API) to calculate similarity scores for pre- and post-surgical photographs of patients undergoing orthognathic surgeries. Our primary objective was to identify which surgical procedure(s) had the greatest effect(s) on similarity score. Methods: Standard treatment progress photographs for 25 retrospectively identified, orthodontic-orthognathic patients were analyzed using the API to calculate similarity scores between the pre- and post-surgical photographs. Photographs from two pre-surgical timepoints were compared as controls. Both relaxed and smiling photographs were included in the study to assess for the added impact of facial pose on similarity score. Surgical procedure(s) performed on each patient, gender, age at time of surgery, and ethnicity were recorded for statistical analysis. Nonparametric Kruskal-Wallis Rank Sum Tests were performed to univariately analyze the relationship between each categorical patient characteristic and each recognition score. Multiple comparison Wilcoxon Rank Sum Tests were performed on the subsequent statistically significant characteristics. P-Values were adjusted for using the Bonferroni correction technique. Results: Patients that had surgery on both jaws had a lower median similarity score, when comparing relaxed expressions before and after surgery, compared to those that had surgery only on the mandible (p = 0.014). It was also found that patients receiving LeFort and bilateral sagittal split osteotomies (BSSO) surgeries had a lower median similarity score compared to those that received only BSSO (p = 0.009). For the score comparing relaxed expressions before surgery versus smiling expressions after surgery, patients receiving two-jaw surgeries had lower scores than those that had surgery on only the mandible (p = 0.028). Patients that received LeFort and BSSO surgeries were also found to have lower similarity scores compared to patients that received only BSSO when comparing pre-surgical relaxed photographs to post-surgical smiling photographs (p = 0.036). Conclusions: Two-jaw surgeries were associated with a statistically significant decrease in similarity score when compared to one-jaw procedures. Pose was also found to be a factor influencing similarity scores, especially when comparing pre-surgical relaxed photographs to post-surgical smiling photographs.

Orthodontic brackets undergo resistance during sliding that includes classical friction, binding, and notching. Current bracket systems are hampered by these challenging forces. As a result, the clinician usually needs to apply additional forces to overcome the resistance which increases the risk of root resorption and discomfort for the patient. This study evaluated frictional properties of a novel bracket that had polytetrafluoroethylene (Teflon™) coated rollers in its design. Five types of brackets (n = 10, each), including a passive self-ligating bracket, a traditional ligated bracket, a three-dimensionally printed direct metal laser sintering (DMLS) bracket with and without Teflon™ rollers, and computer numeric controlled (CNC) machine milled bracket with Teflon™ rollers were tested. The peak resistance values were assessed at 0°, 4°, and 8° of tip on a 0.019 x 0.025” arch wire. At 8° of tip, the DMLS and the CNC milled bracket systems, both with Teflon™ rollers, exhibited less friction as compared to the other brackets tested (p

The purpose of this cross-sectional study was to determine whether patients exhibiting third molar agenesis also exhibit delayed development and/or eruption of the adjacent second molar. The initial panoramic radiographs of 739 patients, 13-17 years of age, from the University of Iowa's Department of Orthodontics were examined. The developmental stage of each second molar according to Demirjian's 8-stage classification system, the eruption stage of each second molar, along with the presence or absence of each third molar were recorded, and Pearson chi-squared tests were used to determine differences in developmental and eruptive timing between those missing third molars and those with third molars present. We conclude that patients missing their maxillary third molars exhibit delayed development of the adjacent maxillary second molars. In addition, patients missing any of their four third molars exhibit delayed eruption of their adjacent second molars. The findings also suggest that mandibular second molars develop later than, but erupt earlier than, maxillary second molars.

This thesis compared tooth widths, arch widths, and arch lengths; their differences between males and females, and changes from early mixed dentitions to adult dentitions. Comparing subjects who were known to have Angle Class I normal occlusion in their permanent dentitions to subjects who were known to be Class I or Class II crowded malocclusions in their permanent dentitions. These comparisons can only be achieved utilizing data from a longitudinal study, such as the Iowa Growth Study. Dental casts in the early mixed dentition (average age of 8.85 years) and in the adult dentition (average age 15.45 years) taken from subjects who did not receive orthodontic treatment during or in the dates prior to data collection were measured for this study. The casts utilized were from the Iowa Growth Study; all of the subjects were of European descent. The longitudinal sample of casts in the Iowa Growth study were made from white dental stone poured into alginate impressions from 1946 until 1960. The objectives of this study were to compare individual tooth widths, mean sum tooth widths, arch widths, arch length segments, and arch perimeters of Class I Normal (CIN) and Class I and II crowded dentitions (CD) in the early mixed (MD) and permanent (PD) dentitions to explore new methods of predicting crowding. The goal was to evaluate the significance of differences between MD and PD for tooth widths, arch lengths, and arch widths in both arches of CIN and CD subjects to determine values that may be useful for MD space analysis. Thirty males and thirty females from the Iowa Growth Study with CIN and CD occlusions were selected from the longitudinal study. Casts of MD and PD subjects were double measured with digital calipers by both the primary and secondary investigators. The average of each investigator's two measurements were used to determine measurement error. All other statistical analysis was based on the mean measurements taken by CPW. Descriptive statistics were computed. The normal non-crowded and crowded samples were compared with two-sample t-test, and changes from MD to PD with paired-sample t-test. Examiner measurement errors were tested with intra-class correlation coefficients. When the mean sums of MD and PD tooth widths were compared, using data from all 60 subjects, the CD group had a significantly greater mean sum of tooth widths than the CIN group. In both genders, crowded dentitions had significantly greater mean sum of tooth widths than CIN's for both the maxilla and mandible in MD and PD. When the mean sums of the arch lengths [Perimeters] were compared using data from all 60 subjects, the arch perimeters of the CD and CIN samples did not differ. It was concluded that total arch lengths Perimeters] were not significant indicators for crowding. Gender comparisons: Within the CIN group, males had numerically larger tooth width sums and arch length sums than females. The sum of maxillary and mandibular tooth widths for CIN's and CD (both males and females) mandibular tooth widths for CIN's and CD (both males and females pooled together and sexes separately. In the MD stage the mean sum of maxillary and mandibular arch lengths in the MD were significantly greater than those in the PD, because arch perimeters decrease during the transition from mixed to permanent dentitions. In summary, the results of this research thesis study showed that the sum of tooth widths in both arches had a significant association with dental crowding. In contrast, the sum of arch lengths [perimeter in both arches] did not differ between the normal and crowded samples. Additional analysis of the measurements taken in this thesis research project, the individual arch length segments, especially the canine and posterior arch length segments in the right and left sides of the lower arch in the mixed dentition casts, and their relation to the sum of the widths of the lower permanent canines and premolars in the normal and crowded malocclusions may give us important information about the development of crowded malocclusions.

Introduction: The purpose of this study was to evaluate the changes in marginal ridge alignment occurring through normal growth and development from early childhood to late adulthood and to examine if any statistical variation exists between males and females. Methods: Dental casts of 38 subjects (15 females and 23 males) from the Iowa Growth Study were selected. The marginal ridge discrepancy was measured as the absolute value difference between adjacent marginal ridges of 20 interproximal contacts with both the ABO tool (data not shown) and a vertically mounted digital caliper. Upper and lower casts were tripoded to a level plane defined by the most posterior tooth and central point of the most erupted central incisor. A 15 subject calibration was used to measure inter-examiner reliability using the Cronbach’s Alpha and Kappa tests. The independent samples t test was used to examine the correlation of marginal ridge discrepancies between males and females. Results: Cronbach alpha (p ≤ .001) and Kappa test (p ≤ .01) show excellent inter-rater reliability. The independent sample t test showed no statistical significance, with minimal exception, in marginal ridge discrepancies between males and females matched for age (p > .05). Group 1 showed significantly higher number of marginal ridge discrepancies within ABO range of 0 – 0.5 mm of males and females compared to Group 2. Conclusion: Based on this study, no statistically significant differences were found in marginal ridge discrepancies between males and females. Also, the magnitude of marginal ridge discrepancies of erupting permanent teeth shows a decrease as an individual proceeds through growth and development and they remain relatively “level” during primary dentition.

The main goal of this pilot study was to determine if a correlation was present between interproximal wear rate and facial form and/or interproximal wear surface area and facial form. Additionally, interproximal wear was evaluated with regards to salivary pH. VPS impressions of interproximal tooth surfaces were captured in 29 adolescent volunteers after orthodontic separation and prior to band placement. A positive replica was created using a type IV die stone. The subsequent die stones were scanned, analyzed and interproximal wear surface area measurments were calculated. Correlation tests revealed that there was no clear or consistent relationship between interproximal wear and facial form and interproximal wear and salivary pH. Methodological limitations were discussed and potential changes for future research were presented.

Introduction: Orthodontic treatment is meant to provide patients with stable occlusion and an esthetic smile, and often improves a patient's self-esteem. Unfortunately, and too often, an ideal orthodontic finish in terms of alignment and occlusion is tarnished by the appearance of white spot lesions on the facial surface of teeth after removing the fixed appliances. These white spots detract from the esthetics of a patient's smile. Purpose: The objective of this study was to evaluate the effectiveness of MI PasteTM (GC America, Alsip, Illinois), MI Paste PlusTM (GC America, Alsip, Illinois), and Topex RenewTM (Sultan Healthcare, Hackensack, NJ) in increasing remineralization and improving the esthetic appearance of white spot lesions in patients after treatment with fixed orthodontic appliances. In addition, at-home only versus in-office and at-home treatment protocols were evaluated. Methods and Materials: Thirty patients were enrolled in four treatment groups and a control group, with six patients in each group. The study lasted three months and results were analyzed with normal and QLF photographs. Results, Discussion, and Conclusion: Upon completion of this clinical study, the following conclusions can be drawn. First, the visible area and the fluorescence decrease of white spot lesions will both significantly lessen after orthodontic treatment regardless of products used, or even with a non-prescription fluoride toothpaste control. Second, there is some evidence that an at-home treatment protocol using Topex Renew, or a combination in-office and at-home treatment protocol with MI Paste Plus, may be more beneficial in reducing the appearance of white spot lesions after orthodontic treatment than other treatment protocols.

Introduction: Class II Division 1 malocclusions are characterized by a retrusive mandible and prominent upper incisors. Despite Class II malocclusions being one of the most frequently treated cases in orthodontists' office, there is no uniform consensus in the orthodontic community on the best treatment modality and biomechanical approach to use in treating patients with Class II malocclusions. Purpose: This paper examines the end-of-treatment outcomes of severe Class II Division I malocclusion patients treated with surgical versus non-surgical approaches. Study Design: This is a retrospective study of consecutively treated severe Class II Division I patients at the University of Iowa. Initial and deband lateral cephalometric radiographs were compared between 45 non-surgical and 21 surgical patients. All patients that were debanded between the ages of 13 to 19 years were included. Multivariable regression analyses were used to examine differences in outcomes between treatment groups. Results: Following adjustment for patient level confounders (age, gender, and race), those treated surgically had better end of treatment cephalometric outcomes. Those treated surgically had a more balanced skeletal profile, greater reduction in overjet, and improvement in ANB angle (p Conclusion: Orthodontic treatment in conjunction with orthognathic surgery is a more ideal treatment for patients with severe Class II Division I malocclusion. When treated surgically, a greater amount of overjet can be reduced while keeping lower incisors in a more stable position in bone.

Introduction: Skeletal expansion has been a treatment modality in orthodontics and orthopedics to correct skeletal transverse discrepancies with maxillary constriction. The utilization of microimplants in conjunction with these palatal expanders offers a higher degree of pure skeletal expansion and minimizes the dental side effects. The purpose of this study is to evaluate the changes of the hard and soft tissues of the face after skeletal expansion for orthodontics. Methods: 36 patients who had received successful expansion with a microimplant assisted rapid palatal expander were compared to their pre-expansion records. All patients received CBCTs from which a 3-D analysis configuration was created to trace hard and soft tissue landmarks of the midface and nasal cavity regions. 3 judges analyzed each set of records and the average was used to calculate the amount of expansion experienced at each anatomical region. A paired T-test and Wilcoxon signed-rank test were used for statistical comparison between time points. Results: Expansion can affect all of the midfacial hard tissues that support the overlying soft tissues. Increases in skeletal width from the Frontozygomatic suture down to the maxillary alveolar bone were all significant. The nasal cavity increased in width in all locations measured. Soft tissue changes were significant at the base of the ala suggesting a widening of the nose with expansion therapy. Conclusion: Maxillary expansion with microimplant assisted expanders can have skeletal changes throughout the entire midface and may affect the width of the nasal cavity. Soft tissue changes were less pronounced, and though a widening of the base of the nose may be expected this may not be noticed by the patient.