Objectives: This study’s primary aims are to evaluate the treatment effects of skeletally anchored maxillary protraction (SAMP) treatment compared to conventional treatment. This study’s secondary aim is to determine SAMP treatment effects on a patient’s airway minimal axial area compared to conventional treatment. Methods: CBCTs were collected from three time points: Initial (before treatment), Progress (after expansion, only for SAMP group), and Final (after treatment). This retrospective study consisted of twenty-three patients who received SAMP treatment (n=23, avg age at initial = 13.5) and twenty-five patients who received conventional treatment (n=25, avg age at initial = 14.5). Cervical vertebral maturation (CVM) and spheno-occipital synchondrosis maturation (SOS) were evaluated. Airway minimal axial area was measured from three dimensional (3D) CBCTs. To evaluate treatment changes, CBCTs were 3D superimposed on the anterior cranial base. Stepwise multiple linear regression was used to evaluate the variables that affect, as well as the magnitude of their effect on, the anterior movement of the maxilla. Results: SAMP group showed significantly more A point movement of 1.98mm compared to 0.65mm seen with conventional treatment (P<0.01). When the patient is 1 year older, A point forward movement decreases by approximately 0.3mm. Pogonion downward movement and condylion to pogonion length were also significantly larger for the SAMP group. The greatest contributing factor for class III correction in the SAMP group was increase in mandibular plane angle (R2 = 0.6; P = 0.0131). SAMP experienced more maxillary molar downward movement and more soft tissue A point forward movement compared to conventional treatment. There is no difference in airway minimal axial area between SAMP and Conventional Groups. Conclusions: SAMP had significantly more ANS and A point forward movement. The most significant dental change was more downward movement of the maxillary molar in the SAMP group. The most significant soft tissue change was from soft tissue A point forward movement in the SAMP group. Age can be used as a predictive factor for magnitude of maxillary protraction in the SAMP group. A majority of the change in ANB correction was due to change in FMA. There is no difference in airway minimal axial area between SAMP and Conventional Groups.

Objectives: This study aimed to compare nasal airway space and anatomy changes in growing patients treated with MARPE, RPE, and a control group, using a novel methodology involving 3D cranial base superimposition to identify stable reference points for more reliable and reproducible measurements. 3D volume segmentation and reconstruction were performed to visualize the changes in nasal cavity structures, including the inferior turbinate. Methods: The sample included 90 growing patients (ages 12-16 years) divided equally (n=30) into three groups: MARPE, RPE, and control, age and sex-matched. Pre- (T1) and post-treatment (T2) CBCT scans were analyzed. Stable reference points were identified via 3D cranial base superimposition. Nasal cavity, inferior turbinate, and airway space widths were measured in three regions (anterior, middle, and posterior). 3D segmentation assessed nasal airway and inferior turbinate changes. Statistical analysis included Student’s t-tests, ANOVA, Post-Hoc Tukey, Wilcoxon signed-rank, Kruskal-Wallis, and Mann-Whitney U tests. Results: The mean ages at T1 for the MARPE, RPE, and control groups were 13.54, 13.05, and 13.32 years, respectively, with no significant differences among the groups. Treatment duration was significantly longer for the MARPE (30.43 months) and RPE (29.63 months) groups compared to the control (23.37 months). Nasal cavity width increased in all three groups, particularly in the middle and posterior regions, with the MARPE group showing the greatest increase. Only the MARPE group showed significant increases in inferior turbinate width (5.20 mm) and volume (344.10 mm3). Nasal airway space significantly increased in both the MARPE and RPE groups, with no significant difference between them, while the control group exhibited no significant changes. 3D reconstructions of the inferior turbinate confirmed these changes, especially in MARPE patients. Conclusions: This study found significant differences in nasal airway space and inferior turbinate changes among MARPE, RPE, and control groups, with MARPE showing the greatest increase in nasal cavity width and turbinate dimensions. Both MARPE and RPE groups significantly expanded nasal airway space. These findings can help guide clinical decisions in treating maxillary transverse deficiency and nasal airway constriction. The novel 3D methodology allowed precise comparisons of nasal structures.

Introduction: Maxillary expansion has been a treatment of choice for correcting transverse skeletal discrepancies, especially in growing patients. For older patients, Mini-implant Assisted Rapid Palatal Expansion (MARPE) offers a promising treatment option. This study compares the treatment outcomes of Conventional MARPE (MSE-II) and Custom 3D-printed MARPE. Methods: This retrospective study analyzed CBCT images from 42 patients aged 16 to 35 years, comparing measurements before (T1) and after (T2) expansion. The conventional (n=21) and custom (n=21) MARPE groups were matched with age and sex. Skeletal and dental changes were evaluated measuring twelve distances and four angles using Dolphin Imaging Software (Chatsworth, Calif). The measurements included frontozygomatic and maxillary widths, nasal cavity width, and dentoalveolar inclination. The effectiveness of each appliance was evaluated based on the maxillary expansion to screw opening ratio, magnitude of expansion, and successful correction of transverse discrepancy. Results: The custom MARPE group demonstrated a significantly greater increase in width across various anatomical landmarks compared to the conventional group. The custom MARPE group achieved nearly a 1:1 ratio of maxillary expansion to screw opening, while only half of expansion screw opening translated to maxillary expansion in conventional MARPE group (P = 0.0001). Logistic regression showed that the odds of successful transverse discrepancy correction were 8.7 times higher with custom MARPE. Conclusions: Custom 3D-printed MARPE can be more effective than conventional MARPE in older patients. The findings of this study suggest that a personalized appliance design and proper mini-implant placement in areas of higher bone density can enhance treatment outcomes.

Abstract CROWN SIZE COMPARISONS IN PATIENTS WITH PALATALLY DISPLACED CANINES By Joseph L. Eliason, D.D.S. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University. Virginia Commonwealth University, 2015 Thesis Director: Steven J. Lindauer, D.M.D., M.Dent.Sc. Professor and Chair, Department of Orthodontics There has been significant debate over the past decades regarding the etiology of palatally displaced canines. Theorized risk factors include agenesis or malformation of the lateral incisors, incisor retroclination, transverse deficiency, or genetic predisposition. The purpose of this study is to compare the linear and volumetric measurements of canines and lateral incisors to determine how tooth size relates to canine impaction. Cone-beam CT images for 40 patients with unilateral palatally displaced canines were utilized to measure the linear dimensions and total crown volume of canines and lateral incisors and to compare those teeth on the impaction side with their isomers on the non-impaction side. Results showed that unilateral palatally impacted maxillary canine crowns were slightly, but statistically significantly wider and larger in volume than their non-impacted isomers. Lateral incisor crowns adjacent to impacted canines were significantly shorter than those adjacent to non-impacted canines.

Introduction: In order to properly diagnose and treatment plan, an orthodontist needs to be knowledgeable about the changes that occur to the maxillary and mandibular dental arches throughout growth. The purpose of this study is to provide an analysis of morphological shape differences seen in the maxillary and mandibular dental arches individually, as well as together, from birth to 3 years of age. Methods: Dental casts from the Iowa Infant Growth study ranging from 2 months to age 4 were photographed in the occlusal plane. The images were landmarked with 3 standard landmarks and 10 sliding semi-landmarks along the curvature of the maxillary and mandibular arches. TpsRelW was used to slide the semi-landmarks and superimpose the date to facilitate shape analysis. MorphoJ was used to determine the degree to which size influences dental arch shape. Once the effects of allometry had been removed, a principal component analysis was run on the residuals to display major features of shape variation in the dataset. Finally, a two block partial least squares analysis was run to determine the degree to which the maxillary and mandibular arches were integrated throughout early growth. Results: Allometry accounts for 9.63% of symmetric shape variation in the maxilla, while it accounts for 56% of symmetric shape variation in the mandible. Asymmetric shape variation is independent of allometry as it only affects 0.34% of the maxillary and 1.46% of the mandibular shape variation. Principal component one accounts for over 60% of all shape variation seen in maxillary and mandibular residuals. Principal component one of symmetric residuals results in a longer, wider dental arch or a shorter, narrower one. Principal component one of asymmetric residuals results in a dental arch with one posterior side being longer and wider while the contralateral side is shorter and narrower. The first three time points (2 months- 1 year) do not display significant integration between the maxillary and mandibular arches. Integration increases with age, displaying significant integration at the last three time points, with the most integration being displayed at 2.5 years. Conclusions: Allometry affects some of the symmetric shape variation in the maxilla, but over half of the symmetric shape variation in the mandible. The asymmetric components are independent of allometry. Integration of the maxillary and mandibular arches increase with age from 2 months to 3 years, peaking at a time point of 2.5 years.

Introduction: Prevalence of childhood obesity is at an all-time high. The effect of childhood obesity on dental development and eruption is a widespread topic today in the dental field. Several cross-sectional studies over the past decade have found an association between advanced dental development and eruption and childhood obesity. The purpose of this study is to examine the longitudinal relationship between childhood Body Mass Index (BMI), and the development of the permanent dentition. Methods: 76 subjects from a longitudinal dataset (Iowa Facial Growth Study 1946-1960) were selected to examine the relationship between BMI and dental development during childhood. Periapical and lateral cephalometric radiographs were used to provide a dental maturity score for each subject using the Demirjian et al. (1973) method at three separate time points (age 4, 8, and 12). BMI was calculated using subjects’ height and weight at each time point. Results: Children with higher BMI’s at all three time points (4, 8 and 12) tended to have advanced dental development compared to children who were of normal weight status. Children who were considered underweight (< 5th BMI percentile) were more likely to be dentally delayed. BMI at age 4 was predictive of dental development status at age 8 and 12. Conclusion: Our results add to the growing body of evidence that childhood obesity is associated with advanced dental development. This is important in the dental and orthodontic fields, as early eruption has been hypothesized to be associated with increased dental caries, crowding, and malocclusions.

Class II malocclusion in non-growing individuals is treated in one of two ways - masking or surgery. If the dentoskeletal discrepancy is great enough, masking usually involves extraction of two maxillary premolars and subsequent incisor retraction and closure of overjet. This is the option of choice for patients without profile concerns, or who have medical or financial concerns. However, this treatment modality can sometimes result in less-than-ideal results. In the present study, we sought to understand what factors may influence the outcomes of this type of treatment. 65 subjects were included in this study. The total sample was divided into good and compromised finish categories based on objective criteria of overbite, overjet, and AP position of the maxillary canines. The good finish group was further subdivided into two groups, acceptable and excellent finishes. Several variables were measured on each subject's initial and final casts and compared between groups to determine whether any were associated with a particular finish group. At the initial time point, a mesial displacement of the maxillary right first molar by 3.35mm or less was found to correspond significantly to an excellent finish. This may indicate that if an individual presents with molars that are Class II by 3 mm or less, the prognosis is better than if that same individual had a greater Class II discrepancy. None of the other variables for the initial time point were found to be significantly different, suggesting that treatment mechanics, rather than a pre-existing occlusal factor, plays a predominant role in treatment outcome. At the final time point, we found that the maxillary arch length and tooth-size arch-length discrepancy were greater in the compromised group, indicative of excess spacing in this group at the end of treatment. Based on the other findings of this study, we attribute this result to differences in the mechanics used by individual practitioners. This hypothesis is further supported by our findings that none of the variables measuring patient compliance were found to be different between the good and compromised group. In the future, studies examining the particular mechanics used, and compliance where applicable, in this population will yield valuable insights into this area of patient research.

Introduction: The purpose of this study was to evaluate the amount of external apical root resorption (EARR) secondary to orthodontic treatment in patients with Short Root Anomaly (SRA) using Cone Beam Computed Tomography (CBCT) at the University of the Pacific Orthodontic Clinic. Material and Methods: In this retrospective study, CBCTs of forty-eight SRA patients who underwent orthodontic treatment were selected from the graduate orthodontic clinic. CBCTs before and after treatment were analyzed to measure root length changes on the upper central and lateral incisors. Results: Differences between the two methods of assessing SRA severity occurred between categorizing mild and moderate SRA subjects with the quantitative method resulting in more moderate cases and visual method determining more mild cases. Root resorption changes ranged from 0.92-1.3 mm for all incisors. Between the Non-Hispanic and Hispanic group, there was no statistical significance for all tooth length changes. There is a statistically significant difference in the root resorption of SRA teeth and non-SRA teeth (0.55mm). Conclusions: Post orthodontic treatment SRA teeth exhibited less linear changes than non SRA teeth and no differences were found between non-Hispanic and Hispanic upper incisors.

The purpose of this study was to compare shear bond strengths of brackets bonded to stainless steel crowns using various orthodontic adhesives and surface conditioning techniques. One hundred and twenty mandibular first molar stainless steel crowns were randomly divided into groups: (1): Aluminablasting + Metal Primer + Assure; (2): Aluminablasting + Silane Coupling Agent + Transbond; (3): Diamond Bur Abrasion + Metal Primer + Assure; (4): Diamond Bur Abrasion + Silane Coupling Agent + Transbond; (5: control): Acid Etching + Metal Primer + Assure; (6: control): Acid Etching + Silane Coupling Agent + Transbond. Bond strength was tested using a universal testing machine. Both aluminablasting and diamond bur abrasion surface preparation techniques, when used in conjunction with metal primer and Assure bonding resin, reached clinically acceptable bond strength values (9.05 and 9.30 MPa, respectively). These techniques seem to offer viable options to bond orthodontic brackets to stainless steel crowns.

Enamel demineralization is a concern in orthodontic patients with poor oral hygiene. To curtail this problem, amorphous calcium phosphate (ACP) containing adhesives have been developed. The purpose of this in vitro study was to evaluate the cariostatic potential of an ACP containing orthodontic bonding agent adjacent to brackets. Sixty human molars were randomly distributed into: ACP adhesive, resin modified glass ionomer cement (RMGIC), and conventional composite resin groups (N=20 each). Brackets were bonded following the manufacturer’s instructions. Tooth enamel through a 2mm window around the brackets was cycled in demineralization (6 hrs) and remineralization (18 hrs) solutions. After 14 days, teeth embedded in resin and were sectioned. Knoop indentations were performed to determine enamel hardness. There were no statistically significant differences between the control and experimental groups. However, both Fuji Ortho LC (RMGIC), and Aegis Ortho (ACP) showed a trend toward a reduction in demineralization. In addition, it was also shown that the initial acid etching of the enamel significantly reduces enamel hardness.