Department of Orthodontics and Oral Facial Genetics

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Facial Soft-Tissue Asymmetry in 3D Cone Beam Computed Tomography Images of Children with Surgically Corrected Unilateral Clefts
(2014-03-01) Starbuck, John M; Ghoneima, Ahmed; Kula, Katherine
Cleft lip with or without cleft palate (CL/P) is a relatively common craniofacial malformation involving bony and soft-tissue disruptions of the nasolabial and dentoalveolar regions. The combination of CL/P and subsequent craniofacial surgeries to close the cleft and improve appearance of the cutaneous upper lip and nose can cause scarring and muscle pull, possibly resulting in soft-tissue depth asymmetries across the face. We tested the hypothesis that tissue depths in children with unilateral CL/P exhibit differences in symmetry across the sides of the face. Twenty-eight tissue depths were measured on cone-beam computed tomography images of children with unilateral CL/P (n = 55), aged 7 to 17 years, using Dolphin software (version 11.5). Significant differences in tissue depth symmetry were found around the cutaneous upper lip and nose in patients with unilateral CL/P.
On the Antiquity of Trisomy 21: Moving Towards a Quantitative Diagnosis of Down Syndrome in Historic Material Culture
(2011) Starbuck, John M
Down syndrome was first medically described as a separate condition from other forms of cognitive impairment in 1866. Because it took so long for Down syndrome to be recognized as a clinical entity deserving its own status, several investigators have questioned whether or not Down syndrome was ever recognized before 1866. Few cases of ancient skeletal remains have been documented to have Down syndrome-like characteristics. However, several forms of material culture may depict this condition. Within this paper the history of our understanding of Down syndrome is discussed. Both skeletal remains and different forms of material culture that may depict Down syndrome are described, and where relevant, debates within the literature about how likely such qualitative diagnoses are to be correct are also discussed. Suggestions are then made for ways in which a quantitative diagnosis can be made to either strengthen or weaken qualitative arguments for or against the diagnosis of Down syndrome in different forms of historic material culture.
Morphological Integration of Soft-Tissue Facial Morphology in Down Syndrome and Siblings
(2011-12) Starbuck, John M; Reeves, Roger H; Richtsmeier, Joan
Down syndrome (DS), resulting from trisomy of chromosome 21, is the most common live-born human aneuploidy. The phenotypic expression of trisomy 21 produces variable, though characteristic, facial morphology. Although certain facial features have been documented quantitatively and qualitatively as characteristic of DS (e.g., epicanthic folds, macroglossia, and hypertelorism), all of these traits occur in other craniofacial conditions with an underlying genetic cause. We hypothesize that the typical DS face is integrated differently than the face of non-DS siblings, and that the pattern of morphological integration unique to individuals with DS will yield information about underlying developmental associations between facial regions. We statistically compared morphological integration patterns of immature DS faces (N = 53) with those of non-DS siblings (N = 54), aged 6–12 years using 31 distances estimated from 3D coordinate data representing 17 anthropometric landmarks recorded on 3D digital photographic images. Facial features are affected differentially in DS, as evidenced by statistically significant differences in integration both within and between facial regions. Our results suggest a differential affect of trisomy on facial prominences during craniofacial development.
Bimaxillary Protrusion with an Atrophic Alveolar Defect: Orthodontics, Autogenous Chin-Block Graft, Soft Tissue Augmentation, and an Implant
(Elsevier, 2015-01) Chiu, Grace; Chang, Chris; Roberts, W. Eugene; Department of Orthodontics and Oral Facial Genetics
Bimaxillary protrusion in a 28 yr female was complicated by multiple missing, restoratively compromised or hopeless teeth. The maxillary right central incisor (#8) had a history of avulsion and replantation, that subsequently evolved into generalized external root resorption with Class III mobility and a severe loss of supporting periodontium. This complex malocclusion had a Discrepancy Index (DI) of 21, and 8 additional points were scored for the atrophic dental implant site (#8). The comprehensive treatment plan was extraction of four teeth (# 5, 8, 12 & 30), orthodontic closure of all space except for the future implant site (#8), augmentation of the alveolar defect with a autogenous chin- block graft, enhancement of the gingival biotype with a connective tissue graft, and an implant-supported prosthesis. Orthodontists must understand the limitations of bone grafts. Augmented alveolar defects are slow to completely turn over to living bone, so they are usually good sites for implants, but respond poorly to orthodontic space closure. However, postsurgical orthodontics treatment is often indicated to optimally finish the esthetic zone prior to placing the final prosthesis. The latter was effectively performed for the present patient resulting in a total treatment time of ~36 months for comprehensive, interdisciplinary care. An excellent functional and esthetic result was achieved, as documented by a Cast-Radiograph Evaluation (CRE) score of 21 and a Pink & White dental esthetics score of 2.
The effects of salivas on occlusal forces
(Wiley, 2015-05) McCrea, Emily S.; Katona, Thomas R.; Eckert, George J.; Department of Orthodontics and Oral Facial Genetics, IU School of Dentistry
Contacting surfaces of opposing teeth produce friction that, when altered, changes the contact force direction and/or magnitude. As friction can be influenced by several factors, including lubrication and the contacting materials, the aim of this study was to measure the occlusal load alterations experienced by teeth with the introduction of different salivas and dental restorative materials. Pairs of molar teeth were set into occlusion with a weighted maxillary tooth mounted onto a vertical sliding assembly and the mandibular tooth supported by a load cell. The load components on the mandibular tooth were measured with three opposing pairs of dental restorative materials (plastic denture, all-ceramic and stainless steel), four (human and three artificial) salivas and 16 occlusal configurations. All lateral force component measurements were significantly different (P < 0·0001) from the dry (control) surface regardless of the crown material or occlusal configuration, while the effects of the artificial salivas compared to each other and to human saliva depended on the crown material.
Microdamage generation by tapered and cylindrical mini-screw implants after pilot drilling
(2014-09) Taing-Watson, Emily; Katona, Thomas R.; Stewart, Kelton T.; Ghoneima, Ahmed; Chu, Gabriel T. M.; Kyung, Hee-Moon; Liu, Sean S.; Department of Orthodontics and Oral Facial Genetics, IU School of Dentistry
Objective: To investigate the relationship between mini-screw implant (MSI) diameter (1.6 vs 2.0 mm) and shape (tapered vs cylindrical) and the amount of microdamage generated during insertion. Materials and Methods: Thirty-six cylindrical and 36 tapered MSIs, 6 mm long, were used in this study. Half of each shape was 1.6 mm in diameter, while the other half was 2.0 mm. After pilot drilling, four and five MSIs were inserted, respectively, into fresh cadaveric maxillae and mandibles of dogs. Bone blocks containing the MSIs were sectioned and ground parallel to the MSI axis. Epifluorescent microscopy was used to measure overall cortical thickness, crack length, and crack number adjacent to the MSI. Crack density and total microdamage burden per surface length were calculated. Three-way analysis of variance (ANOVA) was used to test the effects of jaw, and MSI shape and diameter. Pairwise comparisons were made to control the overall significance level at 5%. Results: The larger (2.0 vs 1.6 mm) cylindrical MSIs increased the numbers, lengths, and densities of microcracks, and the total microdamage burden. The same diameter cylindrical and tapered MSIs generated a similar number of cracks and crack lengths. More total microdamage burden was created by the 2.0-mm cylindrical than the 2.0-mm tapered MSIs. Although higher crack densities were produced by the insertion of 1.6-mm tapered MSIs, there was no difference in total microdamage burden induced by 1.6-mm tapered and 1.6-mm cylindrical MSIs. Conclusions: Pilot drilling is effective in reducing microdamage during insertion of tapered MSIs. To prevent excessive microdamage, large diameter and cylindrical MSIs should be avoided.
Primary failure rate for 1680 extra-alveolar mandibular buccal shelf mini-screws placed in movable mucosa or attached gingiva
(2015-11) Chang, Chris; Liu, Sean S. Y.; Roberts, W. Eugene; Department of Orthodontics and Oral Facial Genetics, IU School of Dentistry
Objective: To compare the initial failure rate (≤4 months) for extra-alveolar mandibular buccal shelf (MBS) miniscrews placed in movable mucosa (MM) or attached gingiva (AG). Materials and Methods: A total of 1680 consecutive stainless steel (SS) 2 × 12-mm MBS miniscrews were placed in 840 patients (405 males and 435 females; mean age, 16 ± 5 years). All screws were placed lateral to the alveolar process and buccal to the lower first and second molar roots. The screw heads were at least 5 mm superior to the soft tissue. Loads from 8 oz–14 oz (227 g–397 g, 231–405 cN) were used to retract the mandibular buccal segments for at least 4 months. Results: Overall, 121 miniscrews out of 1680 (7.2%) failed: 7.31% were in MM and 6.85% were in AG (statistically insignificant difference). Failures were unilateral in 89 patients and bilateral in 16. Left side (9.29%) failures was significantly greater (P < .001) compared with those on the right (5.12%). Average age for failure patients was 14 ± 3 years. Conclusion: MBS miniscrews were highly successful (approximately 93%), but there was no significant difference between placement in MM or AG. Failures were more common on the patient's left side and in younger adolescent patients. Having 16 patients with bilateral failures suggests that a small fraction of patients (1.9%) are predisposed to failure with this method.
Computational fluid dynamics analysis of the upper airway after rapid maxillary expansion: a case report
(SpringerOpen, 2015-05-24) Ghoneima, Ahmed; AlBarakati, Sahar; Jiang, Feifei; Kula, Katherine; Wasfy, Tamer; Department of Orthodontics and Oral Facial Genetics, IU School of Dentistry
BACKGROUND: Assessment of the upper airway volume, morphology, and mechanics is of great importance for the orthodontic patient. We hypothesize that upper airway dimensions have significant effects on the dynamics of the airway flow and that both the dimensions and mechanics of the upper airway are greatly affected by orthodontic and orthopedic procedures such as rapid maxillary expansion (RME). The aim of the current study was to assess the effect of RME on the airway flow rate and pattern by comparing the fluid dynamics results of pre- and post-treatment finite element models. METHODS: Customized pre- and post-treatment computational fluid dynamics models of the patient's upper airway were built for comparison based on three-dimensional computed tomogram. The inhalation process was simulated using a constant volume flow rate for both models, and the wall was set to be rigid and stationary. Laminar and turbulent analyses were applied. RESULTS: Comparisons between before and after RME airway volume measurements showed that increases were only detected in nasal cavity volume, nasopharynx volume, and the most constricted area of the airway. Pressure, velocity, and turbulent kinetic energy decreased after dental expansion for laminar and turbulent flow. Turbulent flow shows relatively larger velocity and pressure than laminar flow. CONCLUSIONS: RME showed positive effects that may help understand the key reasons behind relieving the symptom of breathing disorders in this patient. Turbulence occurs at both nasal and oropharynx areas, and it showed relatively larger pressure and velocity compared to laminar flow.
An analytical approach to 3D orthodontic load systems
(The Angle Orthodontist, 2014-09) Katona, Thomas R.; Isikbay, Serkis C.; Chen, Jie; Department of Orthodontics and Oral Facial Genetics, IU School of Dentistry
OBJECTIVE: To present and demonstrate a pseudo three-dimensional (3D) analytical approach for the characterization of orthodontic load (force and moment) systems. MATERIALS AND METHODS: Previously measured 3D load systems were evaluated and compared using the traditional two-dimensional (2D) plane approach and the newly proposed vector method. RESULTS: Although both methods demonstrated that the loop designs were not ideal for translatory space closure, they did so for entirely different and conflicting reasons. CONCLUSIONS: The traditional 2D approach to the analysis of 3D load systems is flawed, but the established 2D orthodontic concepts can be substantially preserved and adapted to 3D with the use of a modified coordinate system that is aligned with the desired tooth translation.
Biology of biomechanics: Finite Element Analysis of a Statically Determinate System to Rotate the Occlusal Plane for Correction of Skeletal Class III Openbite Malocclusion
(Elsevier, 2015-12) Roberts, W. Eugene; Viecilli, Rodrigo F.; Chang, Chris; Katona, Thomas R.; Paydar, Nasser H.; Department of Orthodontics and Oral Facial Genetics, IU School of Dentistry
Introduction In the absence of adequate animal or in-vitro models, the biomechanics of human malocclusion must be studied indirectly. Finite element analysis (FEA) is emerging as a clinical technology to assist in diagnosis, treatment planning, and retrospective analysis. The hypothesis tested is that instantaneous FEA can retrospectively simulate long-term mandibular arch retraction and occlusal plane rotation for the correction of a skeletal Class III malocclusion. Methods Seventeen published case reports were selected of patients treated with statically determinate mechanics using posterior mandible or infrazygomatic crest bone screw anchorage to retract the mandibular arch. Two-dimensional measurements were made for incisor and molar movements, mandibular arch rotation, and retraction relative to the maxillary arch. A patient with cone-beam computed tomography imaging was selected for a retrospective FEA. Results The mean age for the sample was 23.3 ± 3.3 years; there were 7 men and 10 women. Mean incisor movements were 3.35 ± 1.55 mm of retraction and 2.18 ± 2.51 mm of extrusion. Corresponding molar movements were retractions of 4.85 ± 1.78 mm and intrusions of 0.85 ± 2.22 mm. Retraction of the mandibular arch relative to the maxillary arch was 4.88 ± 1.41 mm. Mean posterior rotation of the mandibular arch was –5.76° ± 4.77° (counterclockwise). The mean treatment time (n = 16) was 36.2 ± 15.3 months. Bone screws in the posterior mandibular region were more efficient for intruding molars and decreasing the vertical dimension of the occlusion to close an open bite. The full-cusp, skeletal Class III patient selected for FEA was treated to an American Board of Orthodontics Cast-Radiograph Evaluation score of 24 points in about 36 months by en-masse retraction and posterior rotation of the mandibular arch: the bilateral load on the mandibular segment was about 200 cN. The mandibular arch was retracted by about 5 mm, posterior rotation was about 16.5°, and molar intrusion was about 3 mm. There was a 4° decrease in the mandibular plane angle to close the skeletal open bite. Retrospective sequential iterations (FEA animation) simulated the clinical response, as documented with longitudinal cephalometrics. The level of periodontal ligament stress was relatively uniform (<5 kPa) for all teeth in the mandibular arch segment. Conclusions En-masse retraction of the mandibular arch is efficient for conservatively treating a skeletal Class III malocclusion. Posterior mandibular anchorage causes intrusion of the molars to close the vertical dimension of the occlusion and the mandibular plane angle. Instantaneous FEA as modeled here could be used to reasonably predict the clinical results of an applied load.

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