The anatomical limit and strategies for molar movement during orthodontic treatment / 口腔疾病防治

@#In many cases, tooth movement over a considerable distance is needed to meet the major goal of orthodontic treatment, which has always been to correct malocclusion and improve the facial profile in patients with skeletal malocclusion. However, tooth movement over a considerable distance also carries risks of dehiscence, fenestration, root exposure, and so forth. The reason lies in neglecting many limits for tooth movement, especially anatomical characteristics. This review focuses on structural limits for orthodontic molar movement, such as the alveolar cortex, the maxillary sinus floor, and the mandibular canal. In addition, we set the strategy in clinical orthodontics. For the alveolar cortex and the mandibular canal, orthodontists are recommended to move the root away from the cortical bone initially and formulate personalized molar movement plans according to clinical examination and cone-beam computed tomography (CBCT) and other imaging examinations. First, the molar root was controlled by torque away from the bone plate, and then, the molar movement amount and direction were controlled according to the personalized movement path. In regard to the maxillary sinus floor, light and continuous forces and scientific biomechanics are suitable for bodily tooth movement. In summary, better therapeutic efficacy and long-term stabilization could be achieved by circumventing the limits and risks caused by anatomical limitations and characteristics.

Research progress on trace elements-modified titanium implant surfaces / 口腔疾病防治

@#Traditional titanium implants are bioinert, and some biological properties, such as osteogenic and antibacterial properties, can be obtained by adding different trace elements to their surfaces. These trace elements can help enhance implant-bone binding and effectively prevent peri-implantitis. Different trace elements have different advantages, and different modification methods can also affect the biological properties. In this paper, the biological properties of titanium implant surfaces modified by trace elements were reviewed. The results of a literature review show that implant surfaces modified by fluoride, silver, zinc, manganese, etc. can inhibit the growth of bacteria and reduce the negative impact on normal cells from bacteria. Other elements, such as strontium, tantalum and cobalt, can promote the differentiation of osteoblasts on the surface of titanium implants, improve the activity of alkaline phosphatase, and improve the expression of osteogenic genes, thus increasing the amount of bone formation and enhancing the strength of implant-bone integration. Most elements have multiple properties, and the combined application of two or more elements can yield more biological properties than a single element. Since there are many trace elements in the human body, there is still a wide research space available in the field of the surface modification of dental implants by trace elements.

Research progress on the distribution of primary cilia and related signaling pathways involved in odontogenesis / 口腔疾病防治

@#Primary cilia are organelles present on most mammalian cells that sense environmental changes and transduce signaling, and they are the key coordinators of various signaling pathways during tissue development. This article reviews the progress of research on the distribution of primary cilia in tooth development and the related signaling pathways. A literature review shows that in odontogenesis, primary cilia play an important role in the mutual induction of the epithelium and mesenchyme; during the continuous proliferation and differentiation of cells, the distribution of primary cilia is temporally and spatially dependent. Although the reason for this distribution is still unclear, some experimental evidence indicates that this phenomenon is compatible with the function of cells and tissues in which primary cilia are distributed. Primary cilia are involved in the regulation of two important signaling pathways, Hedgehog and Wnt, in odontogenesis. Genes encoding cilia (such as Kif3a, Evc/Evc2 and Ift) can affect the development of teeth by regulating these two signaling pathways, and there is an interaction between the two signaling pathways. Deletion of related genes (such as Ofd1 and Bbs) can damage the transmission of upstream and downstream signals by damaging the structure or function of cilia, thereby causing various types of dental dysplasia, including small teeth, enamel hypoplasia, missing teeth, or craniofacial deformities.