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ExperimentaL Oral Medicine
Published in Samuel Dreizen, Barnet M. Levy, Handbook of Experimental Stomatology, 2020
Samuel Dreizen, Barnet M. Levy
Striking gross and microscopic dental defects were found in the incisor, premolar, and molar teeth of the pregnant rabbits infected with vaccinia. Hypoplastic lesions in the incisors became grossly evident approximately 160 days after inoculation. Linear grooving and pitting of the coronal surfaces were characteristic. Histologically, both the enamel and dentin showed intermittent abnormal matrix formation and hypocalcification. Similar changes were noted in the premolars and molars. No dental abnormalities were found in the fetuses or delivered young of mothers infected with vaccinia, regardless of stage of gestation when the mother was inoculated.
Periodontal Diseases
Published in Lars Granath, William D. McHugh, Systematized Prevention of Oral Disease: Theory and Practice, 2019
William D. McHugh, Lars Matsson, Sigmund S. Socransky
At certain stages during childhood, the gingival reactivity is accentuated and special attention to oral hygiene is needed. At 7 to 8 years of age, the first permanent teeth erupt and the risk of a potentiated gingival reaction is enhanced by the reduced tissue resistance around erupting teeth. Another period when the gingival reactions may be aggravated is around 11 to 13 years of age when cuspids, premolars, and second molars erupt. The increased hormonal activity at this period may further aggravate gingivitis. This is also a period of life when the psychological preparedness to increase plaque control activities often is low. Furthermore, as pointed out earlier in this chapter, the first signs of chronic periodontitis can be found in children of this age.
The Classification of Odontogenic Cysts
Published in Roger M. Browne, Investigative Pathology of the Odontogenic Cysts, 2019
Most previous studies have combined the data for radicular and residual cysts and so there is relatively little information on the age and site distribution of these lesions. This is surprising because in a recent study residual cysts were found to comprise some 10% of odontogenic cysts.43 This study found a predominance in the mandibular premolar region, although they can occur in any part of the jaws. Although radicular cysts are more common in the anterior maxilla, the demand to retain teeth in this part of the jaw for aesthetic reasons probably explains the relatively low incidence of residual cysts. There is evidence too that most residual cysts become progressively smaller in size with age43 and even resolve completely.44
Expression Levels of WNT Signaling Pathway Genes During Early Tooth Development
Published in Organogenesis, 2023
Yuhan Song, Fujie Song, Xuan Xiao, Zhifeng Song, Shangfeng Liu
Wingless-Type MMTV Integration Site Family, Member 10A (Wnt10a) is another important ligand of Wnt signaling pathway, which appears to have specific relevance to skin, its appendages and teeth. Wnt10a is associated with both syndromic and non-syndromic tooth agenesis. Schöpf-Schulz-Passarge syndrome (SSPS) is an autosomal recessive form of ectodermal dysplasia resulting from mutations in Wnt10a.65 Tooth agenesis in SSPS patients can be characterized by conical primary teeth, agenesis of permanent teeth and hypodontia.24 Odonto-onycho-dermal dysplasia (OODD) is a rare autosomal recessive syndrome mainly characterized by dry hair, anodontia of permanent teeth, smooth tongue, keratoderma, and hyperhidrosis.26 Recently, Wnt10a mutations were found in patients with nonsyndromic tooth agenesis as well, mainly characterized by oligodontia and agenesis of the maxillary permanent canines. Upper and lower premolars were the most affected missing teeth.12,21 In our research, Wnt10a was significantly expressed in E18.5 (early bell stage) and P1 (late bell stage) stages and the expression level decreased in P7 phase. Our results implied that Wnt10a played an important role in the formation of tooth hard tissue.
Evaluation of biomechanics using different traction devices in distalization of maxillary molar with clear aligners: a finite element study
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Construction of finite element model: 3D finite element models of the whole maxillary dentition with periodontal ligaments (PDLs) and alveolar bone were built using GEOMAGIC studio (Raindrop Geomagic, North Carolina, USA). Teeth and maxillary bone were reconstructed based on cone-beam CT (KAVO, German) scanning of an adult female subject with normal occlusion (Figure 1A). In order to establish the natural anatomy, PDLs were constructed as a linear elastic film with an average thickness of 0.25 mm around the roots of all the teeth (Figure 1B). In the next step, the alveolar bone was generated to fit the teeth and PDLs, and the alveolar bone design was under the cemento-enamel junction relation. The aligners had a thickness of 0.75 mm, in which external offset devices for all crowns and attachments were developed in the simulation (Comba et al. 2017). Canine, first and second premolars were designed with vertical rectangular attachments (Figure 2). The micro-implant (DENTOS, Korea) was positioned between the second premolar and the first molar at an angle of 45° with the occlusal plane. At the height of 4 mm and 6 mm from the alveolar crest respectively, the force of 150 g was applied to the spring that was attached to the traction device and the micro-implant (Figure 1D–F). All components were imported for FE analysis by ANSYS Workbench 15.0 (Ansys, Pennsylvania, USA).
miR-200a-3p represses osteogenesis of human periodontal ligament stem cells by targeting ZEB2 and activating the NF-κB pathway
Published in Acta Odontologica Scandinavica, 2022
Qing Wang, Haiyan Lin, Jinxiang Ran, Ziran Jiang, Qingyuan Ren, Wulin He, Hui Xiao
Fresh premolars without any caries were extracted from the healthy individual aged 18–23 old due to orthodontics. The PDL tissues were gently scraped from the middle one-third of the root to prevent the contamination of gingival and cementum cells. The tissues were cut into small pieces and placed in a 35-mm culture dish for cell transplantation. The cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM) containing 10% foetal bovine serum (FBS; 10270, Gibco, Grand Island, NY, USA), 2 mM L-glutamine (35050, Gibco), 100 U/mL penicillin, 100 μg/mL streptomycin and 250 μg/mL amphotericin B (Antibiotic-Antimycotic; 15240, Gibco) at 37 °C with 5% CO2 and saturated humidity. The medium was refreshed every 48 h. Cells were passaged at 1:3 until reaching 70% confluence.