ABSTRACT
Orthodontic tooth movement elicits alveolar bone remodeling and orofacial pain that is manifested by tooth mechanical hyperalgesia. Nerve growth factor (NGF) is upregulated in periodontium and may modulate tooth mechanical hyperalgesia. The objectives were to examine the role of NGF in tooth mechanical hyperalgesia and to elucidate the underlying mechanisms. Tooth mechanical hyperalgesia was induced by ligating closed coil springs between incisors and molars in Sprague-Dawley rats. Retrograde labeling was performed by periodontal administration of fluor-conjugated NGF and the detection of fluorescence in trigeminal ganglia (TG). Lentivirus vectors carrying NGF shRNA were employed to knockdown the expression of NGF in TG. The administration of agonists, antagonists, and virus vectors into TG and periodontium was conducted. Tooth mechanical hyperalgesia was examined through the threshold of biting withdrawal. Our results revealed that tooth movement elicited tooth mechanical hyperalgesia that could be alleviated by NGF neutralizing antibody and that NGF was upregulated in periodontium (mainly in periodontal fibroblasts) and TG. Retrograde labeling revealed that periodontal NGF was retrogradely transported to TG after day 1. Acid-sensing ion channel 3 (ASIC3) and NGF were co-expressed in trigeminal neurons and the percentage of co-expression was significantly higher following tooth movement. The administration of NGF and NGF neutralizing antibody into TG could upregulate and downregulate the expression of ASIC3 in TG, respectively. NGF aggravated tooth mechanical hyperalgesia that could be alleviated by ASIC3 antagonist (APETx2). Moreover, NGF neutralizing antibody mitigated tooth mechanical hyperalgesia that could be recapitulated by ASIC3 agonist (GMQ). NGF-based gene therapy abolished tooth mechanical hyperalgesia and downregulated ASIC3 expression. Taken together, in response to force stimuli, periodontal fibroblasts upregulated the expressions of NGF that was retrogradely transported to TG, where NGF elicited tooth mechanical hyperalgesia through upregulating ASIC3. NGF-based gene therapy is a viable method in alleviating tooth-movement-induced mechanical hyperalgesia.
ABSTRACT
Orthodontic pain that is induced by tooth movement is an important sequela of orthodontic treatment and has a significant effect on patient quality of life. Studies have shown that the high expression of transient receptor potential vanilloid 1 (TRPV1) in trigeminal ganglions plays a vital role in the transmission and modulation of orofacial pain. However, little is known about the role of TRPV1 in orthodontic pain. In this study, male Sprague-Dawley rats were randomly assigned to six groups to study the role of TRPV1 in the modulation of tooth-movement pain. The expression levels of TRPV1 mRNA and protein were determined by real-time PCR and western blot, respectively. Moreover, pain levels were assessed using the rat grimace scale (RGS). The role of TRPV1 in modulating tooth-movement pain was examined by injecting a TRPV1 antagonist into the trigeminal ganglia of rats. A lentivirus containing a TRPV1 shRNA sequence was constructed and transduced into the rats' trigeminal ganglia. The results showed that the expression levels of TRPV1 protein and mRNA were elevated following tooth-movement pain. Pain levels increased rapidly on the 1 day, peaked on the 3 day and returned to baseline on the 14 day. The TRPV1 antagonist significantly reduced tooth-movement pain. The lentivirus containing a TRPV1 shRNA sequence was able to inhibit the expression of TRPV1 and relieved tooth-movement pain. In conclusion, TRPV1-based gene therapy may be a treatment strategy for the relief of orthodontic pain.
Subject(s)
Animals , Male , Rats , Calcitonin Gene-Related Peptide , Genetic Therapy , Molar , Pain , Quality of Life , Random Allocation , Rats, Sprague-Dawley , TRPV Cation Channels , Tooth Movement Techniques , Trigeminal GanglionABSTRACT
Clear aligner treatment achieves patients' precise tooth movements through utilizing patients' digital dental models and tooth movement planning by orthodontists. Originated from the rudimentary form in 1940's, clear aligner has undergone many innovations and developments. A strict selection of extraction patients for clear aligner treatments is a prerequisite of good treatment outcomes. Orthodontists should first master the unique features of aligner biomechanics and mechanisms. For extraction patients treated with clear aligners, orthodontists should focus on anchorage control, torque control and vertical control, and strictly monitoring treatment progressions, as to achieve satisfactory treatment outcomes. With the development of dental materials and techniques, we believe that clear aligner treatment will be a mainstay of future orthodontic treatments.
ABSTRACT
Objective To investigate the clinical application value of padded molars.Methods Totally 54 cases of malocclusions from Department of Orthodontics of West China Hospital of Stomatology were received occlusal pads by optiband ultra band bongding at the early stage of orthodontic treatment (1th -5thmonth).The lateral cephalometric radiographs before and after treatments were analyzed.The effects on vertical height of molars after using padded molars were observed.Results The padded molars did not affect the vertical height without statistical difference (P ＞ 0.05).Conclusions Temporary using padded molars were feasible in orthodontic treatment.Padded molars may be widely applied in clinical orthodontics.
ABSTRACT
Objective To investigate the clinical application value of psychological induction in impression taking of deciduous crossbite.Methods Totally 84 children of deciduous crossbite receiving impression taking were divided equally into 2 groups.Children in the control group received impression taking directly,while children in the experimental group received psychological induction before impression taking.A comparative study was carried out according to special cooperative behavior assessment for children.Results The cooperation degree of the experiment group was increased significantly after psychological induction with statistical differences between them(P ＜ 0.05).Conclusions Psychological induction can improve the cooperation degree of children in impression taking.
ABSTRACT
Objective To evaluate the effectiveness of Typodont-based table clinic competition (TCC) on undergraduate orthodontic education. Methods Students who have finished basic orthodon-tic courses made diagnosis,treatment strategy and performed orthodontic treatment for malocclusion cases on Typodonts. A self-design questionnaire was employed to investigate their perception to this pedagogy. Results The majority of participants(82.2%-92.9%) highly evaluated Typodont-based TCC. Conclu-sions Typodont-based TCC course is conducive to arousing students' study internets and to promoting association between theory and practice.