Department of Orthodontics and Oral Facial Genetics Works
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Item Potential Application of 4D Technology in Fabrication of Orthodontic Aligners(Frontiers Media, 2022) Elshazly, Tarek M.; Keilig, Ludger; Alkabani, Yasmine; Ghoneima, Ahmed; Abuzayda, Moosa; Talaat, Wael; Talaat, Sameh; Bourauel, Christoph P.; Orthodontics and Oral Facial Genetics, School of DentistryObjectives: To investigate and quantify forces generated by three-dimensional-printed aligners made of shape memory polymers (four-dimensional [4D] aligner). Methods: Clear X v1.1 material was used in this study. On a custom-made typodont model, correction of maxillary central incisor (tooth 21) malposition by 4D aligners with thicknesses of 0.8 and 1.0 mm was measured by superimposition of subsequent scans. Maximum deflection forces generated by foil sheet specimens were measured at different temperatures in three-point bending (3-PB) tests. In a biomechanical system (orthodontic measurement and simulation system [OMSS]), forces generated on movements of tooth 21 by the 4D aligners were measured at different temperatures. Results: 4D aligners succeeded to achieve a significant tooth movement (2.5 ± 0.5 mm) on the typodont, with insignificant difference between different thicknesses. In the 3-PB test, the maximum deflection forces measured at 20, 30, 37, 45, and 55°C, were 3.8 ± 1.1, 2.5 ± 0.9, 1.7 ± 0.6, 1.0 ± 0.4, and 0.5 ± 0.4 N, respectively. Forces delivered on palatal displacement of tooth 21 at 37, 45, and 55°C by 0.8-mm aligners were 0.3 ± 0.1, 0.2 ± 0.1, and 0.7 ± 0.2 N, respectively, whereas those by 1.0-mm aligners were 0.3 ± 0.1, 0.3 ± 0.1, and 0.6 ± 0.2 N, respectively. A good concordance with movement on the typodont model was shown in OMSS. Conclusion: An initial study of 4D-printed aligner shows its ability to move a tooth by biocompatible orthodontic forces, after a suitable thermal stimulus within the oral temperature range.Item Primary Evaluation of Shape Recovery of Orthodontic Aligners Fabricated from Shape Memory Polymer (A Typodont Study)(MDPI, 2021-03-10) Elshazly, Tarek M.; Keilig, Ludger; Alkabani, Yasmine; Ghoneima, Ahmed; Abuzayda, Moosa; Talaat, Sameh; Bourauel, Christoph P.; Orthodontics and Oral Facial Genetics, School of DentistryAs an innovative approach to overcome the rate-limiting staging of conventional aligners, using shape memory polymers (SMPs) as aligners’ materials was investigated in this in vitro study. The ability of SMPs to shape recover and consequently move tooth, upon appropriate stimuli, was evaluated on a typodont model before clinical application. The study design was to achieve 1.9 mm correction movement of an upper central incisor by one aligner after multiple steps/activation. A custom-made aligned typodont model with a movable upper central incisor was scanned. Using an orthodontic software and a 3D printer, resin-models were generated. Seven aligners of ClearX sheets (SMPs) were fabricated by thermoforming on the resin aligned model. Each aligner was tested for repositioning of the central incisor in the typodont model. The model was scanned after each step and the corrective movement was measured through the superimposition of scans. Results showed that the total correction efficiency of the SMPs’ aligner was ≈93% (1.76 mm). The corrective movement was 0.94 ± 0.04 mm after the reforming step, 0.66 ± 0.07 mm after the first activation step, and 0.15 ± 0.10 mm after the second activation step. It was concluded that aligners made of SMPs could have a promising future-use in orthodontic aesthetic treatment.Item Decoding Deep Learning applications for diagnosis and treatment planning(SciELO, 2023-01-06) Retrouvey, Jean-Marc; Conley, Richard Scott; Orthodontics and Oral Facial Genetics, School of DentistryIntroduction: Artificial Intelligence (AI), Machine Learning and Deep Learning are playing an increasingly significant role in the medical field in the 21st century. These recent technologies are based on the concept of creating machines that have the potential to function as a human brain. It necessitates the gathering of large quantity of data to be processed. Once processed with AI machines, these data have the potential to streamline and improve the capabilities of the medical field in diagnosis and treatment planning, as well as in the prediction and recognition of diseases. These concepts are new to Orthodontics and are currently limited to image processing and pattern recognition. Objective: This article exposes and describes the different methods by which orthodontics may benefit from a more widespread adoption of these technologies.Item Sclerostin antibody corrects periodontal disease in type 2 diabetic mice(American Society for Clinical Investigation, 2024-07-18) Turkkahraman, Hakan; Flanagan, Shannan; Zhu, Tianli; Akel, Nisreen; Marino, Silvia; Ortega-Gonzalez, Dayane; Yuan, Xue; Bellido, Teresita; Orthodontics and Oral Facial Genetics, School of DentistryType 2 diabetes (T2D) is on the rise worldwide and is associated with various complications in the oral cavity. Using an adult-onset diabetes preclinical model, we demonstrated profound periodontal alterations in T2D mice, including inflamed gingiva, disintegrated periodontal ligaments (PDLs), marked alveolar bone loss, and unbalanced bone remodeling due to decreased formation and increased resorption. Notably, we observed elevated levels of the Wnt signaling inhibitor sclerostin in the alveolar bone of T2D mice. Motivated by these findings, we investigated whether a sclerostin-neutralizing antibody (Scl-Ab) could rescue the compromised periodontium in T2D mice. Administering Scl-Ab subcutaneously once a week for 4 weeks, starting 4 weeks after T2D induction, led to substantial increases in bone mass. This effect was attributed to the inhibition of osteoclasts and promotion of osteoblasts in both control and T2D mice, effectively reversing the bone loss caused by T2D. Furthermore, Scl-Ab stimulated PDL cell proliferation, partially restored the PDL fibers, and mitigated inflammation in the periodontium. Our study thus established a T2D-induced periodontitis mouse model characterized by inflammation and tissue degeneration. Scl-Ab emerged as a promising intervention to counteract the detrimental effects of T2D on the periodontium, exhibiting limited side effects on other craniofacial hard tissues.Item Mandibular advancement appliance effects on obstructive sleep apnoea: a prospective threedimensional computed tomography study(Sciendo, 2017) Ghoneima, Ahmed; Bodkin, Cynthia; Stewart, Kelton; Perlow, Mark J.; Starbuck, John; Kula, Katherine; Orthodontics and Oral Facial Genetics, School of DentistryBackground: The aim of this study was to determine the effects of an elastic mandibular advancement (EMA) appliance on upper airway dimensions, most constricted area (MCA) of the airway, and snoring in a sample of obstructive sleep apnoea (OSA) patients of varying severity. Methods: Forty-seven male subjects were classified into two groups comprising12 controls and 35 suffering from OSA. The OSA group was further divided into three subgroups based on their apnoea-hypopnoea index (AHI). All subjects completed an Epworth questionnaire and an overnight home sleep test before (T1) and at the end of the study (T2). OSA subjects were provided with a custom-made EMA appliance. Cone beam computed tomographic images were obtained for each subject at T1 and T2. Airway parameters were measured and summarised by grouping. The differences in the measurements T1 – T2 were compared using repeated measures analysis of variance (rmANOVA) and p ≤ 0.05 was considered statistically significant. Results: The use of the EMA produced a statistically significant increase in the nasopharyngeal, oropharyngeal, MCA, and total airway volume. Although sleep apnoea patients reported a reduction in snoring time, particularly in moderate and severe OSA groups, the level of improvement was not statistically significant. Patients with moderate and severe OSA demonstrated significant decreases in their AHI and Epworth scores. Conclusion: EMA is effective in reducing OSA severity and changing airway dimensions in OSA patients, specifically in the moderate and severe cases.Item Stress and anxiety in orthodontic residents during the coronavirus disease 2019 pandemic(Elsevier, 2022) Khoo, Edmund; Saeed, Sophia G.; Chiu, Hong-Yan; Quach, Vicky; Janal, Malvin; Stewart, Kelton; Orthodontics and Oral Facial Genetics, School of DentistryIntroduction: The coronavirus disease 2019 pandemic has had far-reaching effects on health care providers and health professional students; however, little is known about the factors related to stress and anxiety levels, specifically among orthodontic residents during this time. Methods: A 2-part questionnaire, which included modified stress and anxiety inventories, was disseminated electronically to U.S. orthodontic residents between June and July 2020. Descriptive and comparative statistics were used to analyze the data. Results: Overall, 261 participants responded (56% female), representing a response rate of 26.8%. Significant gender differences were found in 18 stress items, with female respondents expressing more stress than their male counterparts. Only 1 stress item (ie, fear of being unable to catch up if behind) varied as a function of the difference on the basis of respondents' stage in the program. First-year residents reported more stress in relation to this than more senior residents. Responses to all anxiety items but 1 item varied by gender, with females reporting higher scores. Residents in the middle stages of their program responded with higher anxiety scores with significant differences on 3 anxiety items. Conclusions: Although financial responsibilities and travel plans were the most stressful and anxiety-inducing items for orthodontic residents during the early aspect of the coronavirus disease 2019 pandemic, multiple items contributed to their stress and anxiety. In addition, both gender and stage of progress in a residency program impacted the level of stress and anxiety reported by respondents.Item Wnt/β-catenin Signaling Controls Maxillofacial Hyperostosis(Sage, 2022) Chen, J.; Cuevas, P. L.; Dworan, J. S.; Dawid, I.; Turkkahraman, H.; Tran, K.; Delgado-Calle, J.; Bellido, T.; Gorski, J. P.; Liu, B.; Brunski, J. B.; Helms, J. A.; Orthodontics and Oral Facial Genetics, School of DentistryThe roles of Wnt/β-catenin signaling in regulating the morphology and microstructure of craniomaxillofacial (CMF) bones was explored using mice carrying a constitutively active form of β-catenin in activating Dmp1-expressing cells (e.g., daβcatOt mice). By postnatal day 24, daβcatOt mice exhibited midfacial truncations coupled with maxillary and mandibular hyperostosis that progressively worsened with age. Mechanistic insights into the basis for the hyperostotic facial phenotype were gained through molecular and cellular analyses, which revealed that constitutively activated β-catenin in Dmp1-expressing cells resulted in an increase in osteoblast number and an increased rate of mineral apposition. An increase in osteoblasts was accompanied by an increase in osteocytes, but they failed to mature. The resulting CMF bone matrix also had an abundance of osteoid, and in locations where compact lamellar bone typically forms, it was replaced by porous, woven bone. The hyperostotic facial phenotype was progressive. These findings identify for the first time a ligand-independent positive feedback loop whereby unrestrained Wnt/β-catenin signaling results in a CMF phenotype of progressive hyperostosis combined with architecturally abnormal, poorly mineralized matrix that is reminiscent of craniotubular disorders in humans.Item Pathophysiology of Demineralization, Part I: Attrition, Erosion, Abfraction, and Noncarious Cervical Lesions(Springer, 2022) Roberts, W. Eugene; Mangum, Jonathan E.; Schneider, Paul M.; Orthodontics and Oral Facial Genetics, School of DentistryPurpose of the review: Compare pathophysiology for infectious and noninfectious demineralization disease relative to mineral maintenance, physiologic fluoride levels, and mechanical degradation. Recent findings: Environmental acidity, biomechanics, and intercrystalline percolation of endemic fluoride regulate resistance to demineralization relative to osteopenia, noncarious cervical lesions, and dental caries. Summary: Demineralization is the most prevalent chronic disease in the world: osteoporosis (OP) >10%, dental caries ~100%. OP is severely debilitating while caries is potentially fatal. Mineralized tissues have a common physiology: cell-mediated apposition, protein matrix, fluid logistics (blood, saliva), intercrystalline ion percolation, cyclic demineralization/remineralization, and acid-based degradation (microbes, clastic cells). Etiology of demineralization involves fluid percolation, metabolism, homeostasis, biomechanics, mechanical wear (attrition or abrasion), and biofilm-related infections. Bone mineral density measurement assesses skeletal mass. Attrition, abrasion, erosion, and abfraction are diagnosed visually, but invisible subsurface caries <400μm cannot be detected. Controlling demineralization at all levels is an important horizon for cost-effective wellness worldwide.Item Pathophysiology of Demineralization, Part II: Enamel White Spots, Cavitated Caries, and Bone Infection(Springer, 2022) Roberts, W. Eugene; Mangum, Jonathan E.; Schneider, Paul M.; Orthodontics and Oral Facial Genetics, School of DentistryPurpose of review: Compare noninfectious (part I) to infectious (part II) demineralization of bones and teeth. Evaluate similarities and differences in the expression of hard tissue degradation for the two most common chronic demineralization diseases: osteoporosis and dental caries. Recent findings: The physiology of demineralization is similar for the sterile skeleton compared to the septic dentition. Superimposing the pathologic variable of infection reveals a unique pathophysiology for dental caries. Mineralized tissues are compromised by microdamage, demineralization, and infection. Osseous tissues remodel (turnover) to maintain structural integrity, but the heavily loaded dentition does not turnover so it is ultimately at risk of collapse. A carious tooth is a potential vector for periapical infection that may be life-threatening. Insipient caries is initiated as a subsurface decalcification in enamel that is not detectable until a depth of ~400μm when it becomes visible as a white spot. Reliable detection and remineralization of invisible caries would advance cost-effective wellness worldwide.Item The LRP5 high-bone-mass mutation causes alveolar bone accrual with minor craniofacial alteration(Wiley, 2023) Turkkahrama, Hakan; Flanagan, Shannan; Zhu, Tianli; Bellido, Teresita M.; Yuan, Xue; Orthodontics and Oral Facial Genetics, School of DentistryBackground and Objective Mutations in low-density lipoprotein receptor-related protein 5 (LRP5) cause various bone diseases. Several mouse models were generated to study the role of LRP5 in bone development. But most of the studies were confined to the appendicular skeleton. The role of LRP5 in the axial skeleton, especially in the craniofacial skeleton, is largely unknown. The aim of this study was to investigate the craniofacial phenotype with the LRP5G171V mutation. Methods To understand how LRP5 affects craniofacial bone properties, we analyzed LRP5 high-bone-mass mutant mice carrying the G171V missense mutation (LRP5HBM). Quantitative microcomputed tomographic imaging and histomorphometric analyses were used to study craniofacial phenotypes and bone density. Histology, immunohistochemistry, and in vivo fluorochrome labeling were used to study molecular mechanisms. Results LRP5HBM mice showed overall minor changes in the craniofacial bone development but with increased bone mass in the interradicular alveolar bone, edentulous ridge, palatine bone, and premaxillary suture. Elevated osteocyte density was observed in LRP5HBM mice, along with increased Runx2 expression and unmineralized bone surrounding osteocytes. Meanwhile, LRP5HBM mice exhibited increased osteoprogenitors, but no significant changes were observed in osteoclasts. This led to a high-bone-mass phenotype, and an increased osteocyte density in the alveolar bone and edentulous ridge. Conclusion LRP5HBM mice display increased bone mass in the alveolar bone with minor changes in the craniofacial morphology. Collectively, these data elucidated the important role of LRP5 in axial bone development and homeostasis and provided clues into the therapeutical potential of LRP5 signaling in treating alveolar bone loss.