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Head Face Med ; 16(1): 29, 2020 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-33213460


BACKGROUND: Periodontal health is of great concern for periodontists and orthodontists in the inter-disciplinary management of patients with bimaxillary protrusion. The aim of present study is to investigate changes in the alveolar bone in the maxillary incisor region and to explore its relationship with displacement of root apex as well as changes in the inclination of maxillary incisors during incisor retraction. METHODS: Samples in this retrospective study consisted of 38 patients with bimaxillary protrusion. Cone-beam computed tomography (CBCT) images was taken before(T0) and after (T1) treatment. Alveolar bone thickness (ABT), height (ABH) and area (ABA) were utilized to evaluate changes in the alveolar bone, while incisor inclination and apex displacement were used to assess changes in the position of maxillary central and lateral incisors. Correlations between alveolar bone remodeling and apex displacement as well as changes in the inclination were investigated. RESULTS: The labial ABT of central and lateral incisors at the mid-root third was increased. In contrast, the palatal ABT at crestal, mid-root and apical third level were consistently decreased. ABH was not altered on the labial side, while significantly decreased on the palatal side. ABA was not significantly increased on the labial side, but significantly decreased on the palatal side, leading to a significantly reduced total ABA. Orthodontic treatment significantly reduced inclination of upper incisors. Changes in the amount (T1-T0) of ABA was remarkably correlated with apex displacement and changes of inclination (T1-T0); in addition, using the multivariate linear regression analysis, changes of ABA on the palatal side (T1-T0) can be described by following equation: Changes of palatal ABA (T1-T0) = - 3.258- 0.139× changes of inclination (T1-T0) + 2.533 × apex displacement (T1-T0). CONCLUSIONS: Retraction of incisors in bimaxillary protrusion patients may compromise periodontal bone support on the palatal side. An equation that incorporated the displacement of root apex and change in the incisor inclination may enable periodontist-orthodontist interdisciplinary coordination in assessing treatment risks and developing an individualized treatment plan for adult patients with bimaxillary protrusion. Moreover, the equation in predicating area of alveolar bone may reduce the risks of placing the teeth out of the bone boundary during 3D digital setups.

Incisivo , Técnicas de Movimiento Dental , Adulto , Remodelación Ósea , Cefalometría , Tomografía Computarizada de Haz Cónico , Humanos , Incisivo/diagnóstico por imagen , Maxilar/diagnóstico por imagen , Estudios Retrospectivos
Am J Orthod Dentofacial Orthop ; 158(6): 868-877, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33008709


This case report describes the treatment of a patient with congenital loss of both mandibular lateral incisors and severely retroclined maxillary incisors. The treatment included bilateral extraction of the maxillary first premolars, accurate 3-digital setup, a 2-stage torque control strategy, and intricate mechanic management. The dilemma of tooth-size discrepancy was solved by ideal torque control to avoid interproximal enamel reduction. An ideal Class I molar and canine relation, as well as canine guidance in the lateral excursion movement, was achieved with good stability.

Incisivo , Diente Molar , Diente Premolar , Oclusión Dental , Humanos , Maxilar/diagnóstico por imagen
Stem Cells Int ; 2020: 2016809, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32215014


Most mesenchymal stem cells reside in a niche of low oxygen tension. Iron-chelating agents such as CoCl2 and deferoxamine have been utilized to mimic hypoxia and promote cell growth. The purpose of the present study was to explore whether a supplement of succinate, a natural metabolite of the tricarboxylic acid (TCA) cycle, can mimic hypoxia condition to promote human periodontal ligament cells (hPDLCs). Culturing hPDLCs in hypoxia condition promoted cell proliferation, migration, and osteogenic differentiation; moreover, hypoxia shifted cell metabolism from oxidative phosphorylation to glycolysis with accumulation of succinate in the cytosol and its release into culture supernatants. The succinate supplement enhanced hPDLC proliferation, migration, and osteogenesis with decreased succinate dehydrogenase (SDH) expression and activity, as well as increased hexokinase 2 (HK2) and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), suggesting metabolic reprogramming from oxidative phosphorylation to glycolysis in a normal oxygen condition. The succinate supplement in cell cultures promoted intracellular succinate accumulation while stabilizing hypoxia inducible factor-1α (HIF-1α), leading to a state of pseudohypoxia. Moreover, we demonstrate that hypoxia-induced proliferation was G-protein-coupled receptor 91- (GPR91-) dependent, while exogenous succinate-elicited proliferation involved the GPR91-dependent and GPR91-independent pathway. In conclusion, the succinate supplement altered cell metabolism in hPDLCs, induced a pseudohypoxia condition, and enhanced proliferation, migration, and osteogenesis of mesenchymal stem cells in vitro.

Huan Jing Ke Xue ; 40(5): 2287-2294, 2019 May 08.
Artículo en Chino | MEDLINE | ID: mdl-31087868


The synergistic process and mechanism of aluminum (Al)-substituted ferrihydrites on arsenic[As(Ⅴ)] and cadmium[Cd(Ⅱ)] were studied under laboratory conditions. The results showed that synergistic adsorption and coprecipitation of As and Cd by Al-substituted ferrihydrites was clearly affected by both the pH of solution and the order in which heavy metals were added. The solution in which As co-existed with Cd for 72 hours, at a pH of 6.0 to 6.5, the As and Cd adsorption capacity of Al-substituted ferrihydrites containing 20% Al (AF20) reached 60.9 mg·g-1 and 17.1 mg·g-1, respectively. The removal rates of As and Cd were 96.0% and 73.0%, respectively. Arsenic and Cd were synergistically adsorbed into the internal pores of AF20 particles, and the synergistic adsorption effect of AF20 on As and Cd was clear. Adding Cd to the solution containing As, for 72 hours, and with a pH of 6.1 to 6.5, the As and Cd adsorption capacity of AF20 was 58.1 mg·g-1 and 12.4 mg·g-1, respectively. The removal rates of As and Cd were 96.0% and 48.3%, respectively. Adsorption of As limited the fixation of Cd by AF20. When adding As to the solution containing Cd, for 72 hours, with a pH of 9.5 to 9.8, fixed amounts of As and Cd on AF20 were 20.9 mg·g-1 and 24.4 mg·g-1, respectively. The removal rates of As and Cd were 38.8% and 98.9%, respectively. The coprecipitation of As and Cd by AF20 was clear. The resulting insoluble As and Cd compounds distributed the Cd distribution in a sparse strip and impeded the further adsorption of As. The results show that Al-substituted ferrihydrites can synergistically adsorb and coprecipitate As and Cd in contaminated environmental media.