The role of CB2 in accelerating orthodontic tooth movement / 安徽医科大学学报

Objective To explore the effect of cannabinoid receptor 2(CB2)on orthodontic tooth movement(OTM)rate and periodontal tissue reconstruction of pressure area in mice.Methods Thirty CB2-/-male mice and thirty littermate control WT male mice were individually accepted the orthodontic appliance at their age of 6 weeks.The mice were respectively scarified at 3 days,7 days,14 days and 21 days after the operation.Then the tooth movement distance was examined through the stereomicroscope.Hematoxylin-eosin staining was performed to explore the biological responses of periodontium at the distal mesial root pressure area.Anti-tartrate acid phospha-tase staining was performed to calculate the number and distribution of osteoclasts at the distal mesial root pressure area,and MMP-9 was evaluated by immunohistochemistry to examine the number of MMP-9(+)monocytes and multinucleated cells in the same district as the TRAP staining.Results Compared with those WT mice at 3,7,14 and 21 days,OTM distance showed a gradual increased tendency according with experimental time over 21 days.The widths of periodontal ligament on the pressure side were markedly greater in CB2-/-mice than WT mice at 7,14 and 21 days(P＜0.000 1).The numbers of TRAP positive osteoclasts were significantly greater in CB2-/-mice than those in WT mice at 14 days of OTM(P＜0.001).MMP-9 immunohistochemical staining showed that the number of MMP-9(+)monocytes and multinucleated cells was more in CB2-/-mice than that in WT mice at 14 days of OTM(P＜0.05).Conclusion The absence of CB2 accelerates orthodontic tooth movement under or-thodontic force.The absence of CB2 reinforces bone resorption in orthodontic tooth movement compressive area dur-ing orthodontic tooth movement.

Role of autophagy in orthodontic tooth movement / 中国组织工程研究

BACKGROUND:The application of orthodontic force triggers autophagy in the periodontal tissue via diverse signaling pathways,augmenting or attenuating the activity of relevant cell types such as periodontal ligament cells,osteocytes,osteoclasts,and osteoblasts,thus facilitating the process of periodontal remodeling. OBJECTIVE:To review the research progress in orthodontic force mediated autophagy in periodontal tissue and its impact on orthodontic tooth movement. METHODS:The PubMed,Web of Science,China Biology Medicine disc and CNKI were searched for literature published from 2010 to 2023 to summarize the progress in orthodontics-related autophagy.And 76 papers were finally included in the analysis and discussion. RESULTS AND CONCLUSION:Orthodontic force can trigger a series of biochemical signal changes through periodontal mechanical receptors and aseptic inflammation they cause,leading to autophagy in periodontal tissue.Subsequently,autophagy generates corresponding feedback through cascaded amplified signaling pathways such as Phosphoinositide 3-kinase/protein kinase B,Hippo,and mitogen-activated protein kinase pathways,promoting periodontal tissue remodeling and ultimately achieving tooth movement and stability.Orthodontic force-induced autophagy can differentially regulate bone resorption on the tooth pressure side and bone formation on the tension side.Related targets have good prospects in the clinical application of orthodontic treatment.Orthodontics and autophagy have complex mechanisms.However,existing research has only focused on exploring the role of autophagy in orthodontic tooth movement.Further exploration is needed to investigate the mutual regulatory effects between autophagy and orthodontic tooth movement,as well as the interactions between upstream mechanical receptors and signaling pathways involved in related pathways.

Clinical research progress on corticotomy and modified techniques for accelerating orthodontic tooth movement / 口腔疾病防治

@#Adjunctive interventions for accelerating orthodontic tooth movement have been a hot topic of interest in orthodontics. Prolonged orthodontic treatment is often associated with multiple potential complications, such as decalcification, caries, root resorption, and gingival inflammation. Therefore, applying adjunctive interventions that accelerate orthodontic tooth movement and reduce the duration of orthodontic treatment can provide patients with numerous benefits that are of profound clinical significance. Currently, adjunctive interventions for accelerating orthodontic tooth movement can be divided into two main categories: surgical and nonsurgical. Surgical interventions, represented by corticotomy and modified corticotomy procedures, are the most common in clinical practice and can minimize the treatment duration, augment alveolar bone, and expand the range of orthodontic tooth movement. However, these procedures are inevitably traumatic and have many risks and limitations that prevent them from being widely used in clinical practice. In recent years, multiple modified corticotomy techniques, such as corticision, piezocision, micro-osteoperforation, and discision, have been proposed; these techniques can reduce soft and hard tissue damage and the incidence of postoperative complications and are relatively easy to perform in the clinic. Corticotomy and other improved surgical techniques can shorten the duration of orthodontic treatment to a certain extent and promote the recovery of periodontal health with no adverse effects on periodontal, dental, or pulp tissues. However, in clinical application, several potential side effects (such as periodontal tissue damage, root resorption, loss of pulp vitality, etc) and shortcomings need further research with long-term follow-up.

Photobiomodulation therapy assisted orthodontic tooth movement: potential implications, challenges, and new perspectives / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Over the past decade, dramatic progress has been made in dental research areas involving laser therapy. The photobiomodulatory effect of laser light regulates the behavior of periodontal tissues and promotes damaged tissues to heal faster. Additionally, photobiomodulation therapy (PBMT), a non-invasive treatment, when applied in orthodontics, contributes to alleviating pain and reducing inflammation induced by orthodontic forces, along with improving tissue healing processes. Moreover, PBMT is attracting more attention as a possible approach to prevent the incidence of orthodontically induced inflammatory root resorption (OIIRR) during orthodontic treatment (OT) due to its capacity to modulate inflammatory, apoptotic, and anti-antioxidant responses. However, a systematic review revealed that PBMT has only a moderate grade of evidence-based effectiveness during orthodontic tooth movement (OTM) in relation to OIIRR, casting doubt on its beneficial effects. In PBMT-assisted orthodontics, delivering sufficient energy to the tooth root to achieve optimal stimulation is challenging due to the exponential attenuation of light penetration in periodontal tissues. The penetration of light to the root surface is another crucial unknown factor. Both the penetration depth and distribution of light in periodontal tissues are unknown. Thus, advanced approaches specific to orthodontic application of PBMT need to be established to overcome these limitations. This review explores possibilities for improving the application and effectiveness of PBMT during OTM. The aim was to investigate the current evidence related to the underlying mechanisms of action of PBMT on various periodontal tissues and cells, with a special focus on immunomodulatory effects during OTM.

Experimental study of subcutaneous adipose-derived stem cells inhibiting orthodontic root resorption / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effect of human subcutaneous adipose-derived stem cells (hADSCs) local transplantation on orthodontically induced root resorption (OIRR) and provide theoretical and experimental basis for the clinical application of hADSCs to inhibit OIRR.@*METHODS@#Forty 8-week-old male Sprague Dawley rats were randomly divided into experimental group and control group, with 20 rats in each group, to establish the first molar mesial orthodontic tooth movement (OTM) model of rat right maxillary. The rats in the experimental group were injected with 25 μL of cell suspension containing 2.5×10 5 hADSCs on the 1st, 4th, 8th, and 12th day of modeling, while the rats in the control group were injected with 25 μL of PBS. The rat maxillary models were obtained before and after 7 and 14 days of force application, and 10 rats in each group were killed and sampled after 7 and 14 days of force application. The OTM distance was measured by stereomicroscope, the root morphology of the pressure side was observed by scanning electron microscope and the root resorption area ratio was measured. The root resorption and periodontal tissue remodeling of the pressure side were observed by HE staining and the root resorption index was calculated. The number of cementoclast and osteoclast in the periodontal tissue on the pressure side was counted by tartrate resistant acid phosphatase staining.@*RESULTS@#The TOM distance of both groups increased with the extension of the force application time, and there was no significant difference ( P<0.05). There was no significant difference in OTM distance between the experimental group and the control group after 7 and 14 days of force application ( P>0.05). Scanning electron microscope observation showed that small and shallow scattered resorption lacunae were observed on the root surface of the experimental group and the control group after 7 days of force application, and there was no significant difference in the root resorption area ratio between the two groups ( P>0.05); after 14 days of application, the root resorption lacunae deepened and became larger in both groups, and the root resorption area ratio in the experimental group was significantly lower than that in the control group ( P<0.05). The range and depth of root absorption in the experimental group were smaller and shallower than those in the control group, and the root absorption index in the experimental group was significantly lower than that in the control group after 14 days of force application ( P<0.05). The number of cementoclast in the experimental group was significantly lower than that in the control group after 7 and 14 days of force application ( P<0.05); the number of osteoclasts in the experimental group was significantly lower than that in the control group after 14 days of force application ( P<0.05).@*CONCLUSION@#Local transplantation of hADSCs may reduce the area and depth of root resorption by reducing the number of cementoclasts and osteoclasts during OTM in rats, thereby inhibiting orthodontic-derived root resorption.

Evaluation of maxillary canine and molar movement during the first phase of extraction space closure: a multilevel analysis

ABSTRACT Objective: This study was designed to analyze and compare the cusp and apex movements of the maxillary canines and first molars during canine retraction in the first step of extraction space closure, and to evaluate if these teeth follow a curvilinear (acceleration and/or deceleration) movement rate. Material and Methods: Twenty-five patients (23.3 ± 5.1 years of age) were enrolled. The retraction of the maxillary canines was accomplished using nickel-titanium closed coil springs (100gf) on 0.020-in stainless steel archwire. Oblique cephalograms were traced and superimposed on the anatomic best fit of the maxilla (before the retraction [T0], and after one month [T1], three [T3], five [T5] and seven [T7] months). Statistics was based in a normally distributed data. Multilevel procedures were used to derive polynomials for each of the measurements. Student's t-test and one-way repeated measures ANOVA were conducted. The level of significance of 5% was adopted. Results: Canine cusps and apexes did not follow a quadratic curve regarding horizontal movement (neither accelerate nor decelerate). Canine and molar cusps showed more horizontal movement than apexes (4.80 mm vs. 2.78 mm, and 2.64 mm vs. 2.17 mm, respectively). Conclusions: Canine did not accelerate or decelerate overtime horizontally; the cusps and apexes of the canines and molars showed more horizontal movement and larger rate at the beginning of canine retraction, followed by significantly smaller and constant movement rate after the first month.

RESUMO Objetivo: O objetivo deste estudo foi analisar a movimentação das cúspides e dos ápices de caninos e primeiros molares superiores durante a retração de caninos na primeira fase do fechamento do espaço pós-extração, e avaliar se esses dentes apresentam mudança na taxa de movimentação (aceleração e/ou desaceleração). Material e Métodos: Vinte e cinco pacientes (idade = 23,3 ± 5,1 anos) foram incluídos. A retração dos caninos superiores foi realizada com molas helicoidais fechadas de níquel-titânio (100gf) em arco 0,020" de aço inoxidável. Foram feitos traçados cefalométricos de telerradiografias oblíquas e sobrepostos ao melhor ajuste anatômico da maxila (antes da retração [T0]; após um mês [T1], três meses [T3], cinco meses [T5] e sete meses [T7]). A estatística foi baseada em dados com distribuição normal. Procedimentos multiníveis foram usados para derivar polinômios para cada uma das medidas. Teste t de Student e ANOVA de uma via para medidas repetidas foram realizados, adotando-se um nível de significância de 5%. Resultados: As cúspides e os ápices dos caninos não seguiram uma curva quadrática em relação ao movimento horizontal (sem aceleração ou desaceleração). As cúspides dos caninos e molares apresentaram mais movimento horizontal do que os ápices (4,80 mm vs. 2,78 mm e 2,64 mm vs. 2,17mm, respectivamente). Conclusões: A movimentação horizontal dos caninos não acelerou ou desacelerou ao longo do tempo; as cúspides e os ápices dos caninos e molares apresentaram maior movimento horizontal e maior taxa de movimentação no início da retração dos caninos, seguida por uma taxa de movimentação significativamente menor e constante após o primeiro mês.

Research progress on the three-dimensional finite element analysis of bite opening / 口腔疾病防治

@#Deep bite is a common clinical malocclusion that has a great impact on patients’ facial aesthetics and oral function. Bite opening is the key step in the treatment of deep bite, playing a decisive role in the development of mandible and the progress of orthodontic treatment. Torque and tip control during the correction of deep bites is a hot topic in orthodontics. The three-dimensional finite element method can accurately simulate clinical processes and conduct dynamic stress analysis, which provides the basis of the biomechanical mechanism. This paper reviewed the finite element analysis of various orthodontic systems for bite opening to provide a reference for clinical application. The emergence of mini-implants provided a new idea for anchorage control in bite opening. Finite element studies found that high-positioned mini-implants are beneficial for bodily tooth intrusion and proposed the ideal position for force application. For the finite element simulation of the reverse curve archwire, it was found that the intrusion and inclination of the anterior teeth increased with the curve depth of the archwire. The application of clear aligners has also been flourishing, but these forces are still difficult to effectively control. Finite element studies on their attachment design and corresponding tooth movement may be helpful to open the bite quickly and effectively. However, the existing studies still have modeling limitations. The structural simplification, linearization and nonstandard parameter definition of the model reduce model accuracy. Additionally, the existing research mostly focused on initial tooth movement, and studies on long-term tooth movement after bone remodeling are lacking. These studies are needed in the future.

Post-trauma complex orthodontic approach: the impact of psychological issues of bullying on treatment decision

ABSTRACT Objective: This article aims to discuss the multidisciplinary approach required in the treatment of cases of impaction and ankylosis of permanent teeth, associated with a history of trauma, considering the psychological state of the child and family when faced with a traumatic case of bullying, by reporting the complex treatment of a central incisor needing to be orthodontically moved across the midline. Conclusion: This clinical case was a major challenge, which included complex multidisciplinary procedures. Results and stability after 26 months of retention indicated successful orthodontic space closure of two maxillary teeth, without the use of implants or prostheses, in an adolescent patient who had a history of dental trauma, alveolar bone loss, and an uncertain initial prognosis.

RESUMO Objetivo: O presente artigo tem como objetivo discutir a abordagem multidisciplinar necessária no tratamento de casos de impacção e anquilose de dentes permanentes, associados a histórico de trauma, considerando o estado psicológico da criança e da família diante de situações traumáticas de bullying, por meio do relato do tratamento complexo de um incisivo central que precisava ser movido ortodonticamente através da linha média. Conclusão: Esse caso foi um grande desafio, que incluiu procedimentos multidisciplinares complexos. Os resultados e a estabilidade após 26 meses de contenção indicaram fechamento ortodôntico bem-sucedido do espaço de dois dentes superiores, sem o uso de implantes ou próteses, em uma paciente adolescente que apresentava histórico de trauma dentário, perda de osso alveolar e prognóstico inicial incerto.

Effect of micro-osteoperforations on the rate of orthodontic tooth movement and expression of biomarkers: a randomized controlled clinical trial

ABSTRACT Introduction: Micro-osteoperforation is a minimally invasive technique that has been used to accelerate orthodontic tooth movement and reduce treatment duration. However, literature presents conflicting reports about this technique. Objective: To evaluate the effectiveness of micro-osteoperforations on the rate of canine retraction and expression of biomarkers in gingival crevicular fluid (GCF). Methods: This was a randomized clinical trial with split-mouth study design. Thirty adult subjects with age above 18 years (20.32 ± 1.96) who required fixed orthodontic treatment and extraction of maxillary first premolars were enrolled and randomly allocated to either the experimental or control group. Randomization was performed by block randomization method, with a 1:1 allocation ratio. The experimental group received three micro-ostoperforations (MOPs) distal to maxillary canine, using the Lance pilot drill. The retraction of maxillary canine was performed with NiTi coil-spring (150g) in both experimental and control groups. The primary outcome was the evaluation of canine retraction rate, measured on study models from the baseline to 16 weeks of canine retraction. Secondary outcomes were the estimation of alkaline and acid phosphates activity in GCF at 0, 1, 2, 3, and 4 weeks. Results: There was a statistically significant difference in the rate of canine retraction only after the first 4 weeks. Subsequently there was no statistically significant difference from the eighth to the sixteenth weeks between MOPs and control group. There was a statistically significant difference in alkaline and acid phosphates activity in GCF between MOPs and control groups during the initial 4 weeks of canine retraction. Conclusion: Micro-ostoperforation increased the rate of tooth movement only for the first 4 weeks; thereafter, no effect was observed on the rate of canine retraction during 8, 12 and 16 weeks. A marked increase in biomarker activity in the first month was observed.

RESUMO Introdução: As micro-osteoperfurações (MOPs) são uma técnica minimamente invasiva que tem sido utilizada para acelerar a movimentação dentária ortodôntica e reduzir o tempo de tratamento. No entanto, existem relatos conflitantes sobre o uso dessa técnica. Objetivo: Avaliar a eficácia das MOPs em acelerar a taxa do movimento de retração de caninos e na expressão de biomarcadores no fluido crevicular gengival (FCG). Métodos: Esse foi um ensaio clínico randomizado com desenho de estudo do tipo boca dividida. Trinta indivíduos adultos com idade acima de 18 anos (20,32 ± 1,96 anos) que necessitavam de tratamento ortodôntico fixo e extração de primeiros pré-molares superiores foram incluídos e aleatoriamente alocados para o grupo experimental ou grupo controle. A randomização foi realizada pelo método de randomização em bloco, com proporção de alocação de 1:1. O grupo experimental recebeu três MOPs distais ao canino superior, utilizando uma broca piloto em formato de lança. A retração do canino superior foi realizada com mola helicoidal de NiTi (150g) nos dois grupos, experimental e controle. O desfecho primário foi a avaliação da taxa de retração dos caninos, medida em modelos de estudo do início da retração até 16 semanas depois. O desfecho secundário foi a estimativa da atividade da fosfatase alcalina e ácida no FCG após 0, 1, 2, 3 e 4 semanas. Resultados: Houve uma diferença estatisticamente significativa na taxa de retração dos caninos somente após as quatro primeiras semanas. Após isso, não houve diferença estatisticamente significativa entre os grupos experimental e controle entre a oitava e a décima sexta semanas. Houve uma diferença estatisticamente significativa na atividade da fosfatase alcaline e ácida no FCG entre os grupos experimental e controle durante as quatro primeiras semanas de retração dos caninos. Conclusão: As micro-osteoperfurações aumentaram a taxa de movimentação dentária apenas nas primeiras quatro semanas; depois disso, nenhum efeito foi observado na taxa de retração dos caninos após 8, 12 e 16 semanas. Houve aumento considerável na atividade do biomarcador no primeiro mês.

External root resorption evaluated by CBCT 3D models superimposition

ABSTRACT Introduction: The literature reports the association of external root resorption (ERR) with orthodontic movement. In cases of premolars extractions, orthodontic movement of anterior teeth is usually quite expressive, which are precisely the most susceptible teeth to suffer from ERR. Objective: The aim of this study was to assess the root morphology of maxillary canines and incisors in patients submitted to four premolar extraction and orthodontic retraction of the anterior teeth, by means of 3D surface models superimposition and mapping. Methods: The sample consisted of six adult patients, five female and one male, with a mean age of 23.5 ± 6.5 years, who underwent orthodontic treatment. All patients presented bimaxillary dental protrusion, with indication of maxillary and mandibular first premolar extractions, followed by the retraction of anterior teeth and space closure. Cone beam CT scans were performed before the beginning of the treatment (T0) and right after space closure (T1). 3D models were built at both times and superimposed to identify the root changes for the given period. Results: All average differences were close to zero and, even when evaluating the extreme values, the observed changes were always smaller than the accuracy of the CBCT. Conclusion: A mild resorption trend was observed, although it was not clinically significant, with values lower than the tomography accuracy.

RESUMO Introdução: A literatura relata a associação de reabsorção radicular externa (RRE) com a movimentação ortodôntica. Nos casos de extrações de pré-molares, a movimentação ortodôntica costuma ser bastante expressiva nos dentes anteriores, que são justamente os dentes mais suscetíveis à RRE. Objetivo: O objetivo do presente estudo foi avaliar a morfologia radicular de caninos e incisivos superiores em pacientes submetidos à extração de quatro pré-molares e retração ortodôntica dos dentes anteriores, por meio da sobreposição e mapeamento de modelos 3D. Métodos: A amostra foi composta por seis pacientes adultos, cinco do sexo feminino e um do masculino, com média de idade de 23,5 ± 6,5 anos, submetidos a tratamento ortodôntico. Todos os pacientes apresentavam biprotrusão dentária, com indicação de extração dos primeiros pré-molares superior e inferior, seguida de retração dos dentes anteriores e fechamento do espaço. A tomografia computadorizada de feixe cônico (TCFC) foi realizada antes do início do tratamento (T0) e logo após o fechamento de espaços (T1). Modelos 3D foram construídos em ambos os momentos e sobrepostos para identificar as mudanças nas raízes dentárias no período determinado. Resultados: Todas as médias das diferenças foram próximas de zero e, mesmo avaliando os valores extremos, as mudanças observadas foram sempre menores que a sensibilidade da TCFC. Conclusão: Observou-se tendência de leve reabsorção, embora não clinicamente significativa, com valores inferiores à sensibilidade tomográfica.

Research progress on factors related to the difficulty of orthodontic tooth movement / 口腔疾病防治

@#Orthodontic tooth movement is a complex physiological process based on periodontal tissue remodeling. Numerous factors, such as the anatomical characteristics of oral and maxillofacial complications, occlusal interference, mechanical factors and systematic factors, may play critical roles in orthodontic tooth movement, leading to tooth movement difficulty. In recent years, many scholars have focused on factors related to tooth movement difficulty, but current research mostly involves animal experiments and retrospective studies. Clinical trials of high-quality and evidence-based medicine studies are required. Although no sound theory system is available that is universally recognized and the mechanism of many factors remains debatable, alveolar bone defects, the maxillary sinus, the gingiva, tooth ankylosis, bone islands and friction may cause orthodontic tooth movement. Understanding the factors related to the difficulty of orthodontic tooth movement is advantageous to develop a more comprehensive personalized treatment plan for patients and achieve more efficient and safer tooth movement. In this paper, the current factors related to orthodontic tooth movement are reviewed to provide references for clinical orthodontic treatment.

Research progress on micro-osteoperforation-assisted orthodontic treatment / 口腔疾病防治

@#As a minimally invasive procedure, micro-osteoperforations (MOPs) achieve desired therapeutic effect with minimal surgical intervention. The operation is relatively simple, and the effect of assisted orthodontic treatment is obvious. However, due to the lack of long-term follow-up studies, there is no unified consensus on the long-term stability of the procedure. This article reviews the research status of MOPs, biological and biomechanical mechanisms, clinical applications and limitations. MOPs can shorten orthodontic treatment time and accelerate tooth movement by exerting regional acceleratory phenomena (RAP). At the same time, this procedure will not damage the health of the periodontal tissue, and the postoperative bleeding and postoperative reaction are minor. In addition, the pain and discomfort of patients were relatively mild and acceptable. However, it also has limitations, mainly including the limited time of the RAP effect of MOPs. Although this procedure is a minimally invasive surgery, there is still a risk of treating regional bone defects. At present, it is still necessary to increase the sample size and extend the follow-up time to evaluate the long-term stability of MOPs.

Research progress on microRNA-21 in regulating osteoclast and osteogenic differentiation in orthodontic treatment / 口腔疾病防治

@#In the process of orthodontic treatment, the balance between the modeling of alveolar bone and the mechanical stress exerted by the appliance is key to the effective movement of orthodontic teeth. Alveolar bone modeling involves many regulatory factors, and microRNAs (miRNAs), as posttranscriptional regulatory factors, play an important role in the occurrence of bone modeling. As an important member of the miRNA family, miRNA-21 promotes the differentiation of periodontal ligament stem cells into osteoblasts and plays an important role in maintaining bone balance and preventing bone resorption as a regulator of osteoclast formation and a promoter of osteoclast differentiation. A literature review showed that miRNA-21 can regulate osteoclast function and promote bone resorption through programmed cell death 4 (PDCD4), phosphate and tension homology deleted on chromosome ten (PTEN), receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG). MiRNA-21 is highly sensitive to external mechanical stress in the process of orthodontic tooth movement. After orthodontic force is applied, miRNA-21 can promote osteoclast formation and accelerate orthodontic movement; through targeted regulation of periodontal ligament associated protein-1 (PLAP-1), it can regulate periodontal ligament remodeling in the late stage of tooth movement and improve the potential of tooth movement. In addition, miRNA-21 mediates orthodontic tooth movement (OTM) and alveolar bone remodeling in the periodontal inflammatory microenvironment. miRNA-21 can upregulate the expression of hypoxia-inducible factor-1α (HIF-1α) in periodontal ligament stem cells in a hypoxic environment. It can promote the expression of osteogenic markers, such as osteopontin (OPN), osteocalcin (OCN), alkaline phosphatase (ALP) and runt-related transcription factor 2 (Runx2), and promote osteogenic differentiation during orthodontic tooth movement.

Effect of different orthodontic forces on the expression of T helper cell 17 cell-related cytokines in the pressure side of periodontal tissue in rats / 华西口腔医学杂志

OBJECTIVES@#This study aimed to explore the changes in the expression of the characteristic transcription factor retinoid related orphan receptor γt (RORγt) and the cytokine interleukin-17 (IL-17) of T helper cell 17 (Th17) in the pressure side of the periodontal tissue of rats under different orthodontic forces. Their effects on the expression of osteoprotegerin (OPG) and the quantity of osteoclast (OC) were also explored. The role of Th17 cell in alveolar bone remodeling under different forces was preliminarily investigated.@*METHODS@#A total of 108 rats were chosen and randomly divided into three groups. Mesial forces of 0, 50, and 100 g were loaded on the maxillary first molar in the three groups. The rats were executed at 0, 1, 3, 5, 7, and 14 days. The expression of RORγt mRNA was quantified by real-time quantitative polymerase chain reaction. The expression of IL-17 protein was quantified by enzyme linked immunosorbent assay. The expression levels of RORγt and OPG proteins were quantified, and the quantity of OC was counted via immunohistochemistry.@*RESULTS@#The expression levels of RORγt and IL-17 and the quantity of OC increased first and then decreased in the 50 and 100 g groups, and the peak values of the two groups were on days 5 and 7, respectively. The expression levels in the 50 g group basically recovered to normal level on day 14, while that in the 100 g group remained at a high level. The expression levels in the 50 g group were higher than those in the 0 g group and lower than those in the 100 g group. The expression of OPG in the 50 g group decreased first, then increased, and finally decreased. It basically recovered to normal level on day 14. The expression of OPG in the 100 g group decreased first and then increased. It remained at a high level on day 14. The expression in the 50 g group was significantly higher than that in the 0 g group on day 7, while the expression in the 100 g group was significantly higher than that in the 0 g group on day 14.@*CONCLUSIONS@#RORγt, IL-17, and OPG were expressed regularly over time under different orthodontic forces, indicating that Th17 participated in the process of bone resorption on the pressure side of periodontal tissue by secreting IL-17.

Effects of Administering the Soybean Isoflavone Genistein on Alkaline Phosphatase Levels During Orthodontic Tooth Movement in Young and Old Rabbits

ABSTRACT@#The goal of this study was to investigate differences in alkaline phosphatase (ALP) levels in young and old rabbits after administering the soybean isoflavone genistein during orthodontic tooth movement. Twelve rabbits were used and assigned to four groups (n = 3); OG (old rabbits), OGS (old rabbits + soybean), YG (young rabbits), and YGS (young rabbits + soybean). The rabbit mandibulary incisors were distalised using a nickel-titanium open coil spring (50 g force). Genistein was administered from the initial orthodontic force delivery until day 21, at a dose of 1.2 mg/kg BW once a day. ALP levels (U/mg) were measured on days 1, 7, 14, 21 after orthodontic force delivery using a UV-Vis 6300 spectrophotometer at a 405 nm wavelength. The results were analysed by one-way analysis of variance followed by Tukey’s Honest Significant Difference (HSD) test (p < 0.05). The ALP levels between the young and old age groups were significantly different. ALP levels were highest in the YGS group, and significantly lowest in the OG group (p < 0.05). Moreover, the ALP level of the OGS group was significantly higher than that in the OG group (p < 0.05). In conclusion, daily consumption of soybean isoflavone genistein could enhance ALP levels during orthodontic tooth movement, particularly in older rabbits.

Effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption / 北京大学学报(医学版)

In recent years, developing new methods to accelerate orthodontic tooth movement (OTM) has attracted extensive attention in the field of orthodontic clinical and scientific research. It reduces orthodontic treatment time and risks. Over the past, various approaches have been done to accelerate orthodontic tooth movement. Several forms of corticotomy techniques have been effective in inducing rapid tooth movement. These techniques activate regional acceleratory phenomenon and create a favorable microenvironment for accelerating tooth movement. Root resorption is one of most common side effects of orthodontic treatment. It affects the long-term viability and health of teeth. However, the effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption still remains unclear. Accelerating tooth movement may have two-side effects on root resorption. Through shortening the treatment period and removing the hyalinized tissues, the acceleration of orthodontic tooth movement could reduce root resorption. The increase of root resorption might be due to the local inflammation and function of cementoclasts/odontoclasts. In this paper, we reviewed the effects of different corticotomy techniques accelerating orthodontic tooth movement on root resorption. Corticotomy techniques deal with mucoperio-steal flaps and bone tissues differently and develop towards minimally invasive. Previous studies on root resorption use two-dimensional images, including apical films and panoramic tomography, to evaluate the degree of root resorption. In recent years, researches measure the volume of root resorption accurately using cone-beam computed tomography (CBCT) and micro-CT. Most studies suggest that the root resorption during acceleration of orthodontic tooth movement through corticotomy techniques is not statistically different from that of traditional orthodontic treatment. Some studies using micro-CT have shown that the root resorption in the groups of corticotomy techniques increases compared with the control group without surgery. Because of the short duration of these studies, the clinical significance is controversial on the overall impact of corticotomy techniques on orthodontic treatment. Accelerating orthodontic tooth movement is still at its emerging phase and need further research in the form of clinical trials to illustrate the effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption.

Clinical and experimental knowledge of photobiomodulation in accelerated orthodontics: A review / Conocimiento clínico y experimental de la fotobiomodulación en ortodoncia acelerada: Una revisión

Background: In recentyears, there has been an increasing interest in finding a noninvasive method to induce the accelerationofdentalmovement,methodssuchaslowintensityvibrations,pulsedelectromagneticfields,andlow-level laser therapy (LLLT). There have been multiple studies on the efficacy of LLLT in animal models, in vitro and in patients without conclusiveresults. Objective: Evaluate the state of the art on the use of LLLT to increase the rate of the orthodontic tooth movement to create a concise reference guide of the different laser and protocols available. Materials and Methods: The authors searched electronic databases (MedLine, Scopus and Semantic Scholar) for articles that evaluated the effectsoflow-leverlasertherapyontheorthodontictoothmovement.Screeningwasperformedatthetitle/abstract and full-text level. Data extraction and quality assessment were performed by two reviewers independently. The reference lists of relevant studies were also screened for further relevantliterature. Results: We found conflicting information as to the efficacy of LLLT to accelerate the orthodontic tooth movement (OTM). There is no consensus in the way the irradiation should be performed. Conclusions: The lack of a standardized irradiation protocol makes it hard to compare conflicting results, even in cases where the laser have the same technical specifications.

Antecedentes: En los últimos años, ha habido un interés creciente en encontrar un método no invasivo para inducir la aceleración del movimiento dental, métodos como vibraciones de baja intensidad, campos electromagnéticos pulsados y terapia con láser de bajo nivel(LLLT). Se han realizado múltiples estudios sobre la eficacia de la LLLT en modelos animales, in vitro y en pacientes sin resultados concluyentes. Objetivo: Evaluar el estado del arte en el uso de LLLT para aumentar la velocidad del movimiento dental ortodóncico para crear una guía de referencia concisa de los diferentes láser y protocolos disponibles. Materiales y métodos: Los autores buscaron en bases de datos electrónicas (MedLine, Scopus y Semantic Scholar) artículos que evaluaran los efectos de la terapia con láser de baja intensidad sobre el movimiento dental ortodóncico. La selección se realizó a nivel de título / resumen y texto completo. Dos revisores realizaron de forma independiente la extracción de datos y la evaluación de la calidad. También se examinaron las listas de referencias de estudios relevantes para obtener más literatura significativa. Resultados:EncontramosinformacióncontradictoriaencuantoalaeficaciadelaLLLTparaacelerarel movimiento dental ortodóncico (OTM).No hay consenso sobre la forma en que se debe realizar lairradiación. Conclusiones: La falta de un protocolo de irradiación estandarizado dificulta la comparación de resultados, incluso en los casos en que el láser tiene las mismas especificaciones técnicas.

Relationship between the polymorphism in the interleukin 1-β and the treatment time of patients subjected to a modified piezocision technique / Relación entre el polimorfismo en la interleucina 1-β y el tiempo de tratamiento de pacientes sometidos a una técnica de piezocisión modificada

Abstract Aim: We aimed to evaluate the correlation between the polymorphism of the interleukin 1-Beta (IL1-β, +3954 C>T) and tooth movement, in a group of Colombian patients undergoing surgically accelerated orthodontic tooth movement. Methods: The study was nested to a controlled clinical trial. Blood samples were taken from 11 women and 29 healthy Colombian male volunteers between 18 and 40 years old, after 1 year of starting orthodontic treatment. The patients presented malocclusion class I, with grade II or III. To detect the genetic polymorphism of the nucleotide +3954 C to T in the IL-1β gene, we used a real-time PCR assay. Results: Eleven individuals presented the allele 2 (T) heterozygous with the allele 1 (T/C) and 19 individuals were homozygous for the allele 1 (C/C). When analyzing the presence of the SNP, no significant differences were found in any of the variables. The best treatment was reflected in Group 3 (selective upper and lower alveolar decortication and 3D collagen matrix) and Group 4 (only selective alveolar decortication in the upper arch, with 3D collagen matrix), with 27% and 35% more speed respectively than in the control group. Conclusions: Our analyses indicated that a reduction in the total treatment time can be mostly potentiated by using decortication and collagen matrices and not for the presence of the allele 2 in the IL-1β. Nevertheless, it is important that further studies investigate if the polymorphism could be associated with the speed of tooth movement and analyze the baseline protein levels.

Resumen Objetivo: Evaluar la correlación entre el polimorfismo de la interleucina 1-Beta (IL1-β, +3954 C> T) y el movimiento de los dientes, en un grupo de pacientes colombianos sometidos a un movimiento dental ortodóncico acelerado quirúrgicamente. Métodos: Este fue un estudio secundario derivado de un ensayo clínico aleatorio controlado. Se tomaron muestras de sangre de 11 mujeres y 29 voluntarios varones colombianos sanos entre 18 y 40 años, después de 1 año de comenzar el tratamiento de ortodoncia. Los pacientes presentaron maloclusión clase I, con grado II o III. Para detectar el polimorfismo genético del nucleótido +3954 C a T en el gen IL-1β, se usó un ensayo de PCR en tiempo real. Resultados: 11 individuos presentaron el alelo 2 (T) heterocigoto con el alelo 1 (T / C) y 19 individuos fueron homocigotos para el alelo 1 (C / C). Al analizar la presencia del SNP, no se encontraron diferencias significativas en ninguna de las variables. El mejor tratamiento se reflejó en el Grupo 3 (decorticación alveolar superior e inferior selectiva y matriz de colágeno 3D) y el Grupo 4 (solo decorticación alveolar selectiva en el arco superior, con matriz de colágeno 3D), con un 27% y un 35% más de velocidad, respectivamente, que en el grupo de control. Conclusiones: Los análisis indicaron que una reducción en el tiempo total de tratamiento puede potenciarse principalmente mediante el uso de decorticación y matrices de colágeno y no por la presencia del alelo 2 en la IL-1β. Sin embargo, es importante que otros estudios investiguen si el polimorfismo podría estar asociado con la velocidad del movimiento de los dientes y analizar los niveles de proteína de referencia.

Innovations in Flapless Corticotomy to Accelerate Orthodontic Tooth Movement: A Review Focusing on the Different Techniques, Limitations and Future Possibilities

@#The aim of this narrative review is to discuss on different approaches of the flapless corticotomy techniques to accelerate orthodontic tooth movement. There was limited understanding about the effect of the surgical procedures because of the great variations in the procedures between the flapless corticotomy techniques. Hence, no specific technique can be claimed to be superior to another. Eleven clinical trials have been reviewed from PubMed, Science Direct, and Google Scholar using the keywords such as accelerated, orthodontic tooth movement (OTM), minimally invasive corticotomy, RAP, corticision, piezocision, lasercision/laser assisted flapless corticotomy (LAFC), micro-osteoperforations (MOPs), discision and their combinations in the last 10 years. Early reports showed that Piezocision, MOPs and LAFC procedures are comparatively less aggressive flapless corticotomy procedure to accelerate OTM and more comfortable to the patient.

Study on the difference of orthodontic tooth movement rate and pressure side bone remodeling between obese and obesity-resistant rats / 上海交通大学学报（医学版）

Objective: To investigate on the difference of the orthodontic tooth movement rate and pressure side bone remodeling between diet-induced obese rats and diet-resistant rats. Methods: Forty male Sprague-Dawley rats were randomly divided into two groups, including the normal diet (ND) group and high-fat diet (HFD) group. And then the HFD group was subdivided into diet-induced obese (DIO) group (n=10) and diet-resistant (DR) group (n=10). Orthodontic applications were placed between the left upper first molar and incisors in rats respectively. After orthodontic treatment for 14 d, the rats were executed and their maxillae were harvested bilaterally. The number of osteoclasts in 3 groups were observed by tartrate-resistant acid phosphatase (TRAP) staining. The expression of osteocalcin in 3 groups was observed by immunohistochemical staining. The tooth movement distance and trabecular bone parameters on the pressure side were measured by Micro-CT. Results: The rate of orthodontic tooth movement was significantly lower in the DR group than that in the DIO and ND groups (P=0.000, P=0.005). After orthodontic treatment for 14 d, the bone mineral density, percentage trabecular bone volume/total volume, trabecular number and trabecular thickness in the DR group were significantly higher than those in the DIO group (P=0.001, P=0.000, P=0.005, P=0.000). The number of osteoclasts in the DR group was significantly lower than that in the ND group and DIO group (P=0.005, P=0.001). The expression of osteocalcin was higher in the DIO group than that in the ND group (P=0.047). Conclusion: High-fat diet-induced obesity or obesity-resistance may affect bone remodeling process during orthodontic treatment by promoting or inhibiting osteoclastogenesis, thereby affecting the rate of tooth movement.