Expert consensus on pediatric orthodontic therapies of malocclusions in children.

Malocclusion, identified by the World Health Organization (WHO) as one of three major oral diseases, profoundly impacts the dental-maxillofacial functions, facial esthetics, and long-term development of ~260 million children in China. Beyond its physical manifestations, malocclusion also significantly influences the psycho-social well-being of these children. Timely intervention in malocclusion can foster an environment conducive to dental-maxillofacial development and substantially decrease the incidence of malocclusion or reduce the severity and complexity of malocclusion in the permanent dentition, by mitigating the negative impact of abnormal environmental influences on the growth. Early orthodontic treatment encompasses accurate identification and treatment of dental and maxillofacial morphological and functional abnormalities during various stages of dental-maxillofacial development, ranging from fetal stages to the early permanent dentition phase. From an economic and societal standpoint, the urgency for effective early orthodontic treatments for malocclusions in childhood cannot be overstated, underlining its profound practical and social importance. This consensus paper discusses the characteristics and the detrimental effects of malocclusion in children, emphasizing critical need for early treatment. It elaborates on corresponding core principles and fundamental approaches in early orthodontics, proposing comprehensive guidance for preventive and interceptive orthodontic treatment, serving as a reference for clinicians engaged in early orthodontic treatment.

Effect and Related Mechanism of Platelet-Rich Plasma on the Osteogenic Differentiation of Human Adipose-Derived Stem Cells.

Objective: Human adipose-derived stem cells (hADSCs) are ideal seed cells for the regeneration of alveolar bone defects. Platelet-rich plasma (PRP), which is rich in growth factors, promotes tissue repair. The purpose of the present study was to investigate whether PRP promotes the osteogenic differentiation of hADSCs and to perform high-throughput sequencing to explore the possible mechanism. Methods: hADSCs were divided into the three following groups: CON group, OM group, and PRP group. Osteogenesis was detected by Alizarin Red staining on day 14. Total RNA was extracted from the OM and PRP groups for high-throughput sequencing. The target genes of the differentially expressed osteogenic-related miRNAs were predicted, and combined miRNA/mRNA analysis was then performed. The mRNA and protein expression levels of hsa-miR-212-5p, type 1 cannabinoid receptor (CNR1), alkaline phosphatase (ALP), Runx2, osteocalcin (OCN), and collagen 1 A1 (COL1A1) in the OM and PRP groups were detected by qRT-PCR and Western blot analyses. The binding between hsa-miR-212-5p and CNR1 was detected by a dual-luciferase reporter assay. Results: Both the OM and PRP groups exhibited enhanced proliferation of hADSCs, and the differences at 48 h and 72 h were statistically significant (P < 0.05). The PRP group had significantly more calcium nodules than the CON group (P < 0.05). Through high-throughput sequencing analysis, differential miRNA and mRNA expression profiles were obtained. During hADSC osteogenesis, the expression of hsa-miR-212-5p was downregulated, and the expression of CNR1 was upregulated. hsa-miR-212-5p was found to bind directly to the 3' UTR of CNR1. Conclusions: The present findings indicated that downregulation of hsa-miR-212-5p and upregulation of CNR1 may be involved in the process by which PRP promotes the osteogenic differentiation of hADSCs.

[A comparative study of tongue appliance combined with chin-cup and facemask in the treatment of anterior crossbite].

PURPOSE: To compare the efficacy of tongue appliance combined with chin-cup and facemask in the treatment of anterior crossbite, as well as the effects on the position of hyoid bone and airway, so as to provide reference for clinic. METHODS: Sixty cases with anterior crossbite were selected after treatment, using tongue appliance combined with chin-cup (n=30) and facemask (n=30). Cephalometric radiographs were taken before and after treatment, skeletal, dental, hyoid, and airway space measurements were analyzed with Winceph 9.0 and AutoCAD 2016. SPSS 21.0 software package was used for statistical analysis. RESULTS: Both appliances had a good effect on anterior crossbite. After treatment, SNA, ANS-PNS significantly increased(P<0.05), and SN-MP significantly increased(P<0.05). The upper anterior teeth showed a buccal inclination(P<0.01), the lower anterior teeth had a lingual inclination, and the overjet became normal(P<0.01). UL-E increased in both groups(P<0.05), PLA significantly increased in tongue appliance combined with chin-cup group(P<0.05). H-C3 decreased in both groups(P<0.05), while H-S, H-Ar increased(P<0.01), suggesting that the hyoid bone moved backward and downward. PNS-UPW increased in both groups(P<0.01), and U-MPW increased in facemask group(P<0.01). CONCLUSIONS: Facemask and tongue appliance combined with chin-cup can both promote the development of the maxilla, cause a clockwise rotation of the mandible, and effectively correct the anterior crossbite. Both methods can cause a backward and downward displacement of hyoid bone. Facemask can enlarge the width of nasopharynx and palatopharynx airway, while only the width of nasopharynx can be increased by tongue appliance combined with chin-cup.

China experts' consensus on preventive and interceptive orthodontic treatments of malocclusions of children.

Malocclusion is one of the three most common oral diseases reported by World Health Organization(WHO). In China, its incidence rate is rising. Malocclusion seriously affects the dental and maxillofacial function, facial appearance and growth development of nearly 260 million children in China, and what is more, it affects their physical and mental health development. Malocclusion occurrence is related to genetic and environmental factors. Early treatment of malocclusion can create a good dental and maxillofacial development environment, correct abnormal growth and control the adverse effects of abnormal genetic factors. It can effectively reduce the prevalence of children's malocclusion and enhance their physical and mental health. This is an urgent need from the economic perspective of our society, so it has great practical and social significance. Experts from the project group "standard diagnose and treatment protocols for early orthodontic intervention of malocclusions of children" which initiated by China National Health Institute of Hospital Administration wrote the "China Experts' Consensus on Preventive and Interceptive Orthodontic Treatments of Malocclusions of Children", which aims to guide and popularize the clinical practice, improve the clinical theory and practice level, and accelerate the disciplinary development of early treatment of children's malocclusion in China. The consensus elaborates the harmfulness of malocclusion and the necessity of early treatment, and brings up the principles and fundamental contents. Based on the law of dental and maxillofacial development, this paper puts forward the guiding suggestions of preventive and interceptive treatments in different stages of dental development ranging from fetus to early permanent dentition. It is a systematic project to promote and standardize the early treatment of malocclusion. Through scientific and comprehensive stratified clinical practice and professional training, the clinical system of early treatment of malocclusion in China will eventually be perfected, so as to comprehensively care for children's dental and maxillofacial health, and improve their oral and physical health in China.

MicroRNA­21 serves an important role during PAOO­facilitated orthodontic tooth movement.

Periodontal accelerate osteogenesis orthodontics (PAOO) is an extension of described techniques that surgically alter the alveolar bone; however, the specific mechanism underlying the technique is not completely understood. The aim of the present study was to evaluate the roles of microRNA (miR)­21 during PAOO. Sprague­Dawley rats were divided into the following four groups: i) Group tooth movement (TM), underwent TM and were administered normal saline (NS); ii) Group PAOO, underwent PAOO + TM and were administered NS; iii) Group agomiR­21, underwent PAOO + TM and were administered agomiR­21; and iv) Group antagomiR­21, underwent PAOO + TM and were administered antagomiR­21. To validate the rat model of PAOO, morphological analyses were performed and measurements were collected. Reverse transcription­quantitative PCR, western blotting and immunohistochemical staining were performed to examine the expression levels of programmed cell death 4 (PDCD4), activin A receptor type 2B (ACVR2b), receptor activator of NF­κΒ ligand (RANKL) and C­Fos. Dual­luciferase reporter assays were performed to validate PDCD4 as a target of miR­21 in vitro. Following 7 days of treatment, the TM distance of group PAOO was longer compared with groups TM and antagomiR­21 (P<0.05), but shorter compared with group agomiR­21 (P<0.05). Tartrate­resistant acid phosphatase staining indicated that following treatment with agomiR­21, osteoclast activity was notably increased, whereas the mRNA and protein expression levels of PDCD4 were notably decreased compared with group PAOO. The mRNA and protein expression levels of RANKL and C­Fos in group agomiR­21 were notably increased compared with group PAOO, whereas group antagomiR­21 displayed the opposite pattern (P<0.05). With regard to ACVR2b, no significant differences were observed among the group agomiR­21 and antagomiR­21 compared with group PAOO. Bioinformatics analysis predicted that PDCD4 was a potential target gene of miR­21, and dual­luciferase reporter assays demonstrated that miR­21 directly targeted PDCD4. In conclusion, the present study demonstrated that miR­21 serves an important role during PAOO­mediated orthodontic TM.

[Effect of premolars scissor bite on the sagittal position of mandible].

PURPOSE: To study the effect of adolescent premolar scissor bite on the sagittal position of mandible and provide proper reference for correct orthodontic diagnosis and right time to treatment. METHODS： One hundred adolescents (54 females, 46 males) with scissor bite of premolars(70 were unilateral,30 were bilateral) were selected as experimental group between 2004 to 2017 from the Department of Orthodontics, Stomatological Hospital of China Medical University. Among them, 54 females served as female group, 46 males served as male group; 30 were bilateral and 70 were unilateral. Lateral cephalograms were recorded before treatment. 16 sagittal hard tissue variables on maxilla and mandible were measured cephalometrically by Winceph 9.0 software, and the cephalometric data were analyzed statistically by using SPSS 21.0 software package. RESULTS: Compared with normal occlusion, Beta angle, SNB, SND, ANB, AB-Plane angle, APDI, convexity angle, facial angle, Wits, Co-Po showed statistically significant difference in both unilateral group and bilateral group (P<0.05). In addition, Go-Pog showed statistically significant difference between normal occlusion and unilateral group(P<0.05). CONCLUSIONS: Adolescents with premolar scissor bite restricts the sagittal position of mandible and tend to have skeletal Ⅱ sagittal jaw relationship. Scissor bite affects the growth of mandible and makes mandibular body length and mandibular length less than normal. More attention should be paid to scissor bite as early as possible to decrease the harmful effects on growth of mandible and sagittal jaw relationship.

[Cephalometric study of tongue crib combined with chincup treatment for anterior crossbite].

PURPOSE: To evaluate the effect of anterior crossbite patients with bad tongue habit treated by tongue crib combined with chincup by cephalometric analysis. METHODS: A total of 25 patients (8 males, 17 females, age range 7-13 years, average age 8.6 years) of anterior crossbite with bad tongue habit or incorrect tongue position were selected. All cases used tongue crib combined with chincup therapy. Lateral cephalometric films taken at the beginning and the end of treatment were analyzed by Winceph 9.0 cephalometric software. All 19 measurement items were assessed by SPSS 17.0 software package. Following the consistency test, Mann-Whitney U test and Wilcoxon singed-rank test were carried out to compare the differences between pre- and post-treatment. RESULTS: All 25 cases obtained satisfactory results, the saggital relative position of maxilla and mandible was improved, anterior crossbite was corrected, occlusion was perfect and bad tongue habit and position were improved. Compared with pre-treatment, SNA, ANB, convexity were U1-SN, U1-NA, overjet and upper lip to E line increased significantly (P<0.05). SN-PP, SN-OP, L1-MP, L1-NB decreased significantly after treatment (P<0.05). The measurement items related to gender were analyzed separately. ANS-PNS and Cd-Gn increased in both male and female (P<0.05). CONCLUSIONS: Tongue crib can effectively correct bad tongue position, promote maxillary forward growth, and prevent the mandible from going ahead combined with chincup. It is an ideal interceptive orthodontic scheme for anterior crossbite with bad tongue habit.

Alveolar bone thickness around maxillary central incisors of different inclination assessed with cone-beam computed tomography.

OBJECTIVE: To assess the labial and lingual alveolar bone thickness in adults with maxillary central incisors of different inclination by cone-beam computed tomography (CBCT). METHODS: Ninety maxillary central incisors from 45 patients were divided into three groups based on the maxillary central incisors to palatal plane angle; lingual-inclined, normal, and labial-inclined. Reformatted CBCT images were used to measure the labial and lingual alveolar bone thickness (ABT) at intervals corresponding to every 1/10 of the root length. The sum of labial ABT and lingual ABT at the level of the root apex was used to calculate the total ABT (TABT). The number of teeth exhibiting alveolar fenestration and dehiscence in each group was also tallied. One-way analysis of variance and Tukey's honestly significant difference test were applied for statistical analysis. RESULTS: The labial ABT and TABT values at the root apex in the lingual-inclined group were significantly lower than in the other groups (p < 0.05). Lingual and labial ABT values were very low at the cervical level in the lingual-inclined and normal groups. There was a higher prevalence of alveolar fenestration in the lingual-inclined group. CONCLUSIONS: Lingual-inclined maxillary central incisors have less bone support at the level of the root apex and a greater frequency of alveolar bone defects than normal maxillary central incisors. The bone plate at the marginal level is also very thin.

MicroRNA expression profile of surgical removed mandibular bone tissues from patients with mandibular prognathism.

BACKGROUND: Mandibular prognathism (MP) or skeletal class III malocclusion with a prognathic mandible is one of the most severe facial deformities. Recent work has revealed certain circulating microRNAs (miRNAs) are associated with MP, we conducted this study to characterize the miRNAs expression profile in surgically removed mandibular bone tissue in patients with MP and explored the role of miRNA regulation in the pathogenesis of MP. METHODS: Affymetrix GeneChip miRNA 3.0 Array was used to examine the miRNA expression in mandibular bone tissues from MP patients and control subjects. A variety of bioinformatic approaches were used to predict the target genes of the miRNAs, find the potential functions and pathways of the target genes, analyze their intersection with differentially expressed mRNAs, and establish miRNA-gene network. RESULTS: Eleven upregulated and 11 downregulated miRNAs with a fold change ≥ 2 and a P value <0.05 were identified in bone specimens of MP patients. A total of 3569 genes were predicted as targets of hsa-miR-10a-5p, hsa-miR-150-5p, hsa-miR-192-5p, hsa-miR-194-5p, hsa-miR-197-3p, hsa-miR-30 d-5p, hsa-miR-342-5p and hsa-miR-629-5p, hsa-miR-1202, and hsa-miR-638. The target genes were predicted to be involved in biological functions and signaling pathways related to osteogenesis. Hsa-miR-30 d-5p was the key node of miRNA-gene network. CONCLUSIONS: Our results indicated a possible association between the differentially expressed miRNAs and MP pathogenesis, and the precise mechanisms are needed to be further validated.

[The relationship between labial-lingual inclination and the thickness of the alveolar bone in the mandibular central incisors assessed with cone-beam computed tomography].

PURPOSE: To investigate the alveolar bone thickness of mandibular central incisors with different labial-lingual inclinations by cone-beam computed tomography (CBCT). METHODS: CBCT and lateral cephalometric images of 60 patients were chosen. The data was respectively classified into 3 groups by L1-MP: lingual inclination group (L1-MP<85.6°); normal group (L1-MP 85.6°-99.6°), and labial inclination group(L1-MP>99.6°). Three-dimensional reconstruction was made for CBCT, and the sagittal images of the largest alveolar bone area along the tooth axis were chosen. The central incisor roots were divided into 4 sections from cementoenamel junction to root apex, then the labial and lingual alveolar bone thickness were measured and added up to get total alveolar bone thickness, and the occurrence of fenestration and dehiscence were recorded. The data was analyzed with SPSS 17.0 software package. RESULTS: The alveolar bone thickness on lingual side and the total bone thickness were significantly different between every 2 sections of all the measured zone. The average values of bone thickness on labial side were thinner than that on lingual side in sections of middle 1/2, root apex 1/4 and root apex. The total bone and lingual bone were thinner in lingual inclination group than in labial inclination group at root apex, root apex 1/4 and middle 1/2. Labial and lingual inclination group were more likely to develop dehiscence (P<0.05). CONCLUSIONS: Lingual and total alveolar bone of central incisors become increasingly thinner from root apex area to cementoenamel junction. The total bone and lingual bone are thinner in lingual inclination group than in labial inclination group. Labial or lingual inclined incisors have higher incidence of dehiscence.

[The relationship between maxillary anterior impacted teeth and sagittal facial type].

PURPOSE: To investigate the relationship between impaction of maxillary anterior teeth and sagittal facial type and evaluate the dentofacial morphological characteristics of patients with maxillary teeth impaction. METHODS: Totally 90 patients with maxillary anterior teeth impaction were divided into 3 groups (one incisor impaction, one canine impaction and two canines impaction), and their cephalometric films were measured and analyzed. They were further divided into Class I, II and III facial types according to ANB and the constituent ratio were calculated. SPSS 17.0 software package was applied for Student's t test and chi-square test. RESULTS: SNA, A'-Ptm' and L1-NB were smaller than the normal value in the 3 groups. Convexity, L1-MP, ANB and Wits appraisal were smaller while AB plane angle, U1-NA and U1-NA were greater than the normal value in groups of one and two canines impaction; S'-Ptm', L1-NB were smaller while U1-L1 was greater than normal value in group of two canines impaction; Among the 3 groups, ANB and Wits appraisal were the smallest while AB plane angle was the greatest in group of two canines impaction. The sagittal facial type of 90 patients was mainly Class I (50%), but Class III in group of two canines impaction increased to 40%. CONCLUSIONS: Impacted maxillary anterior teeth might result in short maxillary basal bone. One canine impaction has the greatest influence than one incisor impaction on sagittal position of jaws. Two canines impaction has the greatest impact on sagittal facial type and tends to be Class III facial type.

[Root resorption after orthodontic treatment: a study of age factor and prevalence in anterior teeth].

PURPOSE: To investigate the impact of age factor on root resorption and the prevalence in anterior teeth during orthodontic treatment. METHODS: Sixty extraction cases treated with straight wire appliance were divided into adult group and child group, with 30 cases in each group.The panoramic radiographs pre-treatment and post-treatment were examined to measure the degrees of root resorption. A total of 360 anterior teeth in each group were evaluated. SPSS 13.0 software package was applied to perform statistical analysis. RESULTS: There was significant difference in root resorption index before and after treatment(P<0.01). The incidence of root resorption increased remarkably after orthodontic treatment. There was significant difference in the degree of root resorption in two groups (P<0.01). The prevalence of root resorption in anterior teeth was: upper central incisors, upper lateral incisors, lower central incisors, lower lateral incisors, upper canines and lower canines. CONCLUSIONS: The root resorption in adult patients are more obvious than child patients. The prevalence of root resorption in anterior teeth is different. Moderate or severe root resorption is prone to happen in upper central incisors or lateral incisors in adult patients.

[First molar extraction in malocclusion: an analysis of 20 consecutive cases].

PURPOSE: To study the feasibility and orthodontic effect of decayed first molar extraction in malocclusion. METHODS: 20 cases with first molar extraction in malocclusion were chosen for this study. There were 3 males and 17 females, aging from 13.5 to 22 years with an average age of 15.6 years . 7 cases were treated with extraction of two lower first molars, 5 cases with extraction of one lower first molar, 2 cases with extraction of four first molars, 2 cases with extraction of one lower first molar and upper first molar, 4 cases with extraction of one upper first molar. All patients were treated with 0.018 edgewise appliance or 0.018 straightwire appliance. The procedure included bonding brackets, putting arch wire, leveling dentition, closing extraction space and adjusting occlusal relationships routinely. RESULTS: When treatment finished, all the 20 cases gained satisfactory results, all the teeth lined up in order ,anterior teeth gained correct overbite and overjet, midline was alignment, molar space was completely closed, occlusion was perfect, the occlusion and facial profile were improved. CONCLUSION: The treatment of decayed first molar extraction in malocclusion could retain more healthy teeth, gain satisfactory orthodontic results, improve the occlusion.

[Changes of interlukin-1beta and tumor necrosis factor-alpha levels in gingival crevicular fluid during orthodontic tooth movement].

OBJECTIVE: To investigate the dynamic changes of interlukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) in gingival crevicular fluid (GCF) during orthodontic tooth movement, and to discuss the biological significance. METHODS: Fifteen patients were chosen as subjects. For each patient, upper and lower canines at one side having one treatment for distal movement by elastic chain served as the experimental teeth, whereas the contralateral ones were used as controls. The GCF were taken before activation and at 1, 24, 48, 72, 168 hours respectively after initiation of the experiment. The levels of IL-1beta and TNF-alpha in GCF were determined by radioimmunoassay. RESULTS: The levels of IL-1beta and TNF-alpha in experimental group began to increase at 24 hours and reached to its peak value at 72 hours after initiation of the experiment, but their levels returned to baseline at 168 hours. Both of them, however, remained at the baseline level in control group. The changes of the two cytokines level were found statistically significant at 48 and 72 hours (P<0.05) between experimental and control group. No statistically significant were observed before activation and at 1, 168 hours after application of orthodontic forces (P>0.05) between experimental and control group. CONCLUSION: The levels of IL-1beta and TNF-alpha in gingival crevicular fluid experience dynamic changes during the early phase of orthodontic treatment, indicate that they might play an important role in the process of alveolar regeneration and tooth movement.

[The activity of M-phase promoting factor in oral normal tissue and tumor].

OBJECTIVE: To investigate the content and activity of M-phase promoting factor (MPF) in pleomorphic adenoma, mucoepidermoid carcinoma, buccal carcinoma and normal tissue, in order to evaluate the role of MPF in the development of tumor and the relationship between MPF and malignant degree. METHODS: The content and activity of MPF were assessed by immunobloting and Gollicano method. RESULTS: The cdc2 and cyclinB (two subunits of MPF) were found both in normal and tumor tissues, and their content in tumor was higher than normal tissues. Buccal carcinoma was 64% higher than normal tissues. The activity of MPF in carcinoma was higher than normal tissue and had positive relation with the malignant extent. CONCLUSIONS: The content and activity of MPF in tumor are higher than normal tissue. PKC can activate MPF. These results show PKC may promote tumor proliferation by activating MPF and also, the activity of MPF has some relation with malignant extent.

[Ectopic expression of cyclin G2 inhibits cell proliferation in HeLa cancer cell line].

BACKGROUND & OBJECTIVE: Cyclins are important proteins in cell cycle machinery, acting as positive regulators in cell proliferation. Cyclin G2 may exceptionally be a negative regulator since its expression could be induced by DNA damage and the VHL tumor suppressor protein. Furthermore, down-regulated cyclin G2 was detected in oral squamous cell carcinomas. The current study was aimed at clarifying the effects of cyclin G2 transgene expression on proliferation of cancer cells in vitro. METHODS: Cyclin G2 cDNA was synthesized by reverse transcription-polymerase chain reaction (RT-PCR) and inserted into the pIRESneo vector at BamH I and BstX I sites to generate the recombinant plasmid pIRES-G2. The pIRES-G2 and pIRESneo plasmids were then individually introduced into HeLa cancer cell line through lipofectamine mediated transfection. After two weeks' selection in culture medium containing G418, the number of colonies was counted and the transfectant cells were morphologically observed. RESULTS: The colony-forming efficiency of the cells transfected with pIRES-G2 construct was much lower compared with that with the control parental vector pIRESneo. The colony numbers were 76.7 +/- 24.8 and 18 +/- 10.4 in control and experimental groups, respectively, with a colony forming rate of 23.4% in the pIRES-G2 group. Furthermore, pIRES-G2 transfected cells showed a senescent morphology. CONCLUSION: Ectopic overexpression of cyclin G2 in cancer cell line HeLa could inhibit cell proliferation significantly.