The success of clear aligner treatment relies on rational treatment planning, favorable patients' compliance and high-quality clinical dental monitoring. High-quality clinical dental monitoring involves not only evaluation of real-time tooth position and treatment-designed tooth position, but also the assessment of the root-alveolar bone relationship. However, fluent imaging tests with ionizing radiation are not realistic in clinical practice. Regarding the rapid advances in digital techniques, biomechanism based method, image processing algorithm-based method and multimodal data fusion-based method all exhibit great potential in monitoring tooth movement. This paper introduced the progress and clinical application in those methods for clinicians′ reference.

OBJECTIVES: To investigate the effect of recombinant human fibroblast growth factor 21 (rhFGF21) on the proliferation and mineralization of cementoblasts and its mechanism. METHODS: Hematoxylin eosin, immunohistochemical staining, and immunofluorescence were used to detect the expression and distribution of fibroblast growth factor 21 (FGF21) in rat periodontal tissues and cementoblasts (OCCM-30), separately. Cell Counting Kit-8 was used to detect the proliferation of OCCM-30 under treatment with rhFGF21. Alkaline phosphatase staining and Alizarin Red staining were used to detect the mineralization state of OCCM-30 after 3 and 7 days of mineralization induction. The transcription and protein expression of the osteogenic-related genes Runx2 and Osterix were detected by real-time quantitative polymerase chain reaction (PCR) and Western blot analysis. The expression levels of genes of transforming growth factor β (TGFβ)/bone morphogenetic protein (BMP) signaling pathway in OCCM-30 were detected through PCR array analysis. RESULTS: FGF21 was expressed in rat periodontal tissues and OCCM-30. Although rhFGF21 had no significant effect on the proliferation of OCCM-30, treatment with 50 ng/mL rhFGF21 could promote the mineralization of OCCM-30 cells after 7 days of mineralization induction. The transcriptional levels of Runx2 and Osterix increased significantly at 3 days of mineralization induction and decreased at 5 days of mineralization induction. Western blot analysis showed that the protein expression levels of Runx2 and Osterix increased during mineralization induction. rhFGF21 up-regulated Bmpr1b protein expression in cells. CONCLUSIONS rhFGF21 can promote the mineralization ability of OCCM-30. This effect is related to the activation of the TGFβ/BMP signaling pathway.
Humans ; Rats ; Animals ; Dental Cementum ; Core Binding Factor Alpha 1 Subunit/metabolism* ; Cell Differentiation ; Bone Morphogenetic Proteins/metabolism* ; Transforming Growth Factor beta/pharmacology*

The health of dental tissue is an important guarantee to obtain good orthodontic effect, and also the basis to achieve beauty, stability and function after orthodontic treatment. The classification of dental diseases is complex and diverse, which has different effects on orthodontic treatment. It is necessary to make clear diagnosis before orthodontic treatment, and take preventive and therapeutic measures according to the etiology and clinical symptoms, so as to achieve the goal of health treatment. Orthodontic treatment might cause a variety of changes in the teeth and pulp tissue. Such changes have certain rules and are complex and variable. Orthodontist should master relevant knowledge to minimize the side effects of orthodontic treatment.

Objective:To evaluate the effect of micro-implant assisted rapid palatal expansion (MARPE) in patients with different radiographic stages of midpalatal suture maturation.Methods:Twenty-eight patients [7 males and 21 females; age (15.5±5.5) years] with maxillary transverse deficiency were selected in the Department of Orthodontics, Hospital of Stomatology, Jilin University from February 2017 to October 2019. According to the fusion of the midpalatal suture, the patients were divided into two groups: 10 patients [3 males and 7 females; age (19.9±6.9) years] were in fusion group and 18 patients [4 males and 14 females; age (13.0±2.4) years] were in non-fusion group. Each patient had cone-beam CT (CBCT) images taken immediately after the placement of micro-implants (T1) and the completion of maxillary expansion (T2). The CBCT images were analyzed using the Dolphin Imaging software to evaluate the amount of midpalatal expansion and the percentages of bony expansion, etc. Statistical analysis was carried out to compare the two groups.Results:After MARPE treatment, the amount of sutural expansion in fusion group was (3.23±1.45) mm while that in non-fusion group was (4.97±1.47) mm ( P<0.05). There was a statistically significant difference in the percentages of bony expansion efficiency between the non-fusion group (71±20)% and the fusion group (46±18)% ( P<0.05). Conclusions:Bony expansion efficiency was affacted by the radiographic stages of midpalatal suture maturation.

Objective: To study the expression characteristics of Wnt5a in cementum of the mice after birth and the effect of Wnt5a on the differentiation of cementoblasts in vitro, and to illuminate the mechanism of Wnt noncanonical signaling in regulating the tooth development. Methods: The postnatal Kunming mice at the days 0. 5, 4. 5, 12. 5, 18. 5, 24. 5 and 30. 5 after birth were selected and divided into various groups by different time points (n=3). The mice were sacrificed and the lower first molar and peridentium were prepared. Immunohistochemical staining was used to detect the expression characteristics of Wnt5a in tooth and peridentium of the mice. The OCCM30 cells were divided into control group and experiment group. 200 μg · L-1 recombinant Wnt5a protein were added in experiment group, and nothing was added in control group; the total RNA in the cells was exrracted. The relative expression levels of Ocn, Opn, Alp, Bsp, Wnt5a, and Runx-2 genes in the OCCM30 cells in two groups were detected by RT-PCR method. Results: At the day 0. 5 after birth, the expression of Wnt5a in the lower first molar tooth germ was negative. At the day 4. 5 after birth, the expression of Wnt5a in ameloblasts and odontoblasts were positive. At the day 16. 5 after birth, the expression of Wnt5a in cementoblasts was positive. At the days 20.5 - 30.5 after birth, the expressions of Wnt5a in odontoblasts and periodontal ligament cells were positive. Compared with control group, the relative expression levels of Ocn and Alp gene in the OCCM30 cells in experiment group were decreased (P<0. 05). Conclusion: The expression of Wnt5a is regular at different tooth developmental stages after birth. Wnt5a can reduce the expression of differentiated genes and play an important role in the growth of cementum.

Objective:To study the expression characteristics of Dickkopf1 (DKK1) in different time and space during tooth development of the postnatal mice, and to provide the theoretical basis for clarifying the mechanism of Wnt signaling pathway in regulating the tooth development.Methods:The postnatal Kunming mice at days 0.5, 6.5, 12.5, 18.5, 24.5, and 30.5 respectively after birth were selected and divided into various groups by time,three in each group.The mice in each group were sacrificed and the paraffin sections of mandibular bone including the first molar were prepared at the thickness of 5 μm, followed by HE staining and immunohistochemical staining in order to detect the expressions of DKK1 in tooth tissue and periodontal tissue.Results:At 0.5 d after birth, the mandibular first molar tooth germ was in the bell stage.At 6.5 d the enamel development of mandibular first molar was almost completed, and the epithelium root sheath extended to the root direction.At 12.5 d the dentin development of crown was completed, with the root formatted about 1/3. At 18.5 d the root had formatted about 2/3.At 24.5 d the root had reached the full length.At 30.5 d the apical foramen was narrow, and the root development was basically completed.There was no DKK1 expression at 0.5 d, but it expressed in the odontoblasts and predentin at 6.5 d. From days 12.5 to 30.5,the expressions of DKK1 were positive in periodontal ligament, alveolar bone, and cellular cementum as odontoblasts, which were gradually increased with the prolongation of time.However, no expression of DKK1 was detected in the pulp.Conclusion:DKK1 shows regular expressions at different tooth developmental stages after birth, suggesting its potential role in the growth of dentin and periodontal tissues.

Objective:To study the changes of oral health indexes in adolescent orthodontic patients under different brushing time, and to provide basis for the orthodontists to give effective dental health promotion in clinic.Methods:A total of 123 adolescent orthodontic patients were included, and they were divided into 1-3min, 3-5 min, 5-7 min and 7-10 min groups based on the brushing time recorded in the period of orthodontic treatment.The relationship between different brushing time and oral health indexes was evaluated 1,3,and 6 months after experiment, such as sulcus bleeding index(SBI),plaque index(PLI), debris index-simplified(DI-S) and enamel demineralization index(EDI).Results:Compared with 1-3 min and 3-5 min groups, the SBI, PLI, and DI-S of the patients in 5-7 min group were significantly reduced(P<0.05).There was no significant differences of SBI, PLI, DI-S , and EDI between 5-7 min group and 7-10 min group (P>0.05).Conclusion:Brushing teeth more than 5 min can improve the oral hygiene significantly and the best time is 5-7 min;the orthodontists should require the patients to brush teeth at least for 5 min.

Objective To explore the changes of PH values of N,O-CMC/β-TCP compositive materials with different mass fractions in simulated body fluids (SBF)and their influence in the growth of MG63 cells, and to illustrate their mechanisms, and to provide reference for the further research on the bone repair materials. Methods The N,O-CMC/β-TCP with mass fractions of 2/1,1/1 and 1/2 were used as experimental groups,and the collagen nano calcium phosphate bone repair material as control group. The materials with different mass fractions were immersed in SBF and the pH values were measured by pH meter after soaking for 7,14,21 and 28d,respectively.The MG63 cells with the concentration of 1 × 105 mL-1 were inoculated and co-cultured in experimental and control groups,the adhesion and morphological changes of MG63 cells in each group were observed by scanning electron microscope and the cell proliferation was detected by MTT method after co-culturing for 2,4 and 6 d.Results The pH values were 6.70-7.25 in N,O-CMC/β-TCP (1/2)group and N,O-CMC/β-TCP (2/1)groups and the pH value in N,O-CMC/β-TCP (1/1)group was basically 7.15. The cells in N,O-CMC/β-TCP (2/1)group formed owe full,spreading face small and less secretion,but the cells in N,O-CMC/β-TCP 1/2 and 1/1 groups formed in full, pseudopodia interconnection, widely spreading and more secretions under electron microscope. The proliferation rate of the cells in N,O-CMC/β-TCP with (1/1 ) and N,O-CMC/β-TCP (2/1)groups had no statistical difference compared with control group (P>0.05),but there was significant difference between control group and N,O-CMC/β-TCP (1/2)group (P<0.05).Conclusion The changes of pH values of N,O-CMC/β-TCP materials with different mass fractions in SBF are small and the pH values are neutral;the order of the mass fraction of N,O-CMC/β-TCP to promote the growth of MG63 cells is 1/1,2/1,and 1/2.

The aim of this study was to compare the pain experience among orthodontic patients treated with self-ligating brackets SmartClip® (3M Unitek, Monrovia, California, USA) and conventional brackets Victory series® (3M Unitek, Monrovia, California, USA). We used a controlled clinical trial study design to compare 69 patients treated with self-ligating to 70 patients treated by conventional brackets. The nickel-titanium archwires 0.012-in were engaged after bonding both arches on the first day; and the visual analogue scale (VAS) was used to assess the pain experience of subjects for the first seven treatment days. The pre-treatment dental study models were assessed by the Little’s irregularity index to quantify the groups’ malalignment characteristics. The self-ligating brackets reported lower pain experience than the conventional group on the first five treatment days. However, the sixth day showed 1.75 mm higher visual analogue score than conventional brackets, with almost equal pain level on the seventh day. The group differences throughout the first week were neither clinically nor statistically significant. The pain experiences in both groups decreased steadily from the third treatment day to the end of the first week of treatment. Based on the study findings, the pain experience during initial alignment is not influenced by the brackets’ ligation type. The pain experience tends to decrease steadily from the third treatment day to the end of the first week of treatment irrespective of the bracket type used.
Orthodontic Brackets, Orthodontic Appliances

OBJECTIVE: To evaluate the short-term effect of fangchinoline, an antiinflammatory drug widely used in Asia, on root resorption that is associated with orthodontic tooth movement. METHODS: Twenty-four Wistar rats were randomly divided into 6 groups. Mesial forces of 0, 50, or 100 g were applied to the maxillary first molar of the rats in each group for 14 days by activating nickel-titanium closed-coil springs. One-half of the rats receiving each of these treatments also received injections of 200 microL fangchinoline every 2 days. Finally, movement of the maxillary first molars was measured using digitized radiographs. The molars were extracted and the surfaces of the root resorption craters were recorded using a scanning electron microscope. The distance the molars moved and resorptionarea ratio was measured, and results were analyzed using 2-way ANOVA tests. RESULTS: There were no statistical differences in the distances the first molars moved under 50 or 100 g force, regardless of treatment with fangchinoline. However, the resorption area ratios were significantly smaller in those rats that were treated with both tension and fangchinoline than in those rats treated by tension alone. CONCLUSIONS: Fangchinoline reduced the resorption area ratio in rats and is therefore an important means of alleviating root resorption.
Animals ; Asia ; Benzylisoquinolines ; Electrons ; Gravitation ; Molar ; Rats ; Rats, Wistar ; Root Resorption ; Tooth ; Tooth Movement