Cellular, molecular, and tissue-level reactions to orthodontic force

FDTooth: Intraoral Photographs and CBCT Images for Fenestration and Dehiscence Detection

Fenestration and dehiscence (FD) pose significant challenges in dental treatments as they adversely affect oral health. Although cone-beam computed tomography (CBCT) provides precise diagnostics, its extensive time requirements and radiation exposure limit its routine use for monitoring. Currently, there is no public dataset that combines intraoral photographs and corresponding CBCT images; this limits the development of deep learning algorithms for the automated detection of FD and other potential diseases. In this paper, we present FDTooth, a dataset that includes both intraoral photographs and CBCT images of 241 patients aged between 9 and 55 years. FDTooth contains 1,800 precise bounding boxes annotated on intraoral photographs, with gold-standard ground truth extracted from CBCT. We developed a baseline model for automated FD detection in intraoral photographs. The developed dataset and model can serve as valuable resources for research on interdisciplinary dental diagnostics, offering clinicians a non-invasive, efficient method for early FD screening without invasive procedures.

Mandibular molar protraction using round Australian wire and miniscrew anchorage with modified corticision in an adult with first molar loss: A case report

A 27-year-old adult female presented with the chief complaint of bilateral mandibular first molar absence and strongly preferred to use wisdom teeth rather than prosthetic replacements. Treatment was carried out using a round Australian wire fixed orthodontic technique. The second and third molars were mesially moved with a bilateral terminal helical loop combined with curved tip-back bends in Australian wire. Miniscrew anchorage was placed in the mandibular premolar area to assist in the protraction of the second and third molars. Additionally, a modified cortical drilling technique was employed to accelerate tooth movement. A neutral molar relationship was established while maintaining the patient's facial profile.

Can fluoxetine influence orthodontic tooth movement? A systematic review and meta-analysis of studies on animal models

INTRODUCTION

Selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine adversely affect bone mineral density (BMD) and turnover, thereby increasing the risk of fractures. The objective of the present systematic review and meta-analysis was to evaluate studies on animal models that assessed whether fluoxetine can influence orthodontic tooth movement (OTM).

MATERIAL AND METHODS

Indexed databases (PubMed/Medline, EMBASE, Cochrane Library, Scopus and ISI Web of Knowledge) and Google Scholar were searched without time and language barriers up to and including June 2024. Original studies that assessed the influence of fluoxetine on OTM were included. Letters to the Editor, reviews, commentaries, perspectives and, in-vitro/ex-vivo studies were excluded. Study selection, and risk of bias (RoB) and quality assessments were assessed. Quantitative assessment (meta-analysis) was also performed using fixed-effects and random effects models.

RESULTS

Four studies performed on male rats were included. Rats in the experimental group underwent OTM with adjunct fluoxetine injections at concentrations ranging between 10-20mg/kg. Orthodontic forces applied ranged between 25-60grams. Three studies reported that fluoxetine does not influence OTM. All studies had a high RoB. Three studies demonstrated low certainty (weak) and two showed very low certainty of evidence. In the meta-analysis, the pooled SMD using a random effects model was 0.05 (95% CI: -0.42 to 0.52), indicating no significant overall effect of fluoxetine on OTM. The analysis revealed substantial heterogeneity across the included studies.

CONCLUSION

Further well-designed and power-adjusted prospective studies are needed to elucidate the role of SSRIs on OTM.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42024563793.

Three-dimensional assessment of mini-implant supported maxillary canine retraction with and without power arm in class II division 1 patients: A split-mouth randomized trial

INTRODUCTION

The primary objectives of this trial were to compare the mechanics of direct sliding (DS) and power arm sliding (PAS) methods for canine retraction in regard to the rate of retraction, rotation, and tipping. The secondary objectives included the evaluation of canine mobility, mini-implant stability, and pain.

MATERIAL AND METHODS

This split-mouth study was conducted over a 12-month intervention period on young adult patients with Class II Division 1 malocclusion requiring extraction of the maxillary first premolars, recruited between July 2023 and January 2024. Retraction methods were randomly assigned to sides by coin toss. Closed coil springs applying 150g retraction forces were stretched to the canine bracket hook on one side and the power arm on the contralateral side. Digital models were analysed to measure canine retraction rate, tipping, and rotation. Canine mobility and mini-implant stability were assessed with the periotest. The pain was evaluated using a visual analogue scale. Data were analysed using two-way mixed ANOVA, and intraclass correlation test. Blinding was only used during data analysis.

RESULTS

Twenty patients (aged 18.35±2.85) were included. The total retraction rate was greater in DS (4.42±0.75mm) compared to PAS (2.93±0.56mm) with P<0.001. Tipping and rotation were significantly higher in DS compared to PAS with P<0.001, P=0.031, respectively. No statistically significant differences were observed between the 2 methods regarding mini-implant stability, and pain. However, canine mobility revealed a significant difference only during the first and second months (P=0.005, P=0.003, respectively) with higher periotest values recorded in the PAS group. No harm was observed during the trial.

CONCLUSIONS

The DS method resulted in a faster rate of retraction than the PAS method. However, the PAS method effectively reduced both tipping and rotation, facilitating a more controlled bodily movement during canine retraction. Trial registration in Clinical-Trial.gov under identification number NCT06352996.

Incidence and risk factors of alveolar bone dehiscences and fenestrations after clear aligner therapy with Class II elastics: a retrospective study

BACKGROUND

In clear aligner therapy (CAT), Class II elastics are widely used to reinforce the anchorage during the distalization of upper molars, however, their association with alveolar bone dehiscences (ABDs) and fenestrations (ABFs) in the anterior region remains unclear. The aim of this research is to assess the incidence of ABDs/ABFs in adult patients undergoing non-extraction CAT with Class II elastics, and to explore risk factors associated with the occurrence of ABDs/ABFs.

METHODS

Thirty adult patients with Class II malocclusion who underwent non-extraction CAT with Class II intermaxillary elastics were enrolled in this study. Cone-beam computed tomography (CBCT) images were obtained before (T0) and immediately after (T1) CAT to assess the occurrence of ABDs/ABFs on the labial and lingual sides of anterior teeth. Chi-square tests were used to compare the incidence of ABDs/ABFs at T0 and T1, meanwhile, binary logistic regression was utilized to analyze the risk factors associated with ABDs/ABFs at T1.

RESULTS

On the labial side, the incidence of ABDs increased significantly in the mandibular central incisors (from 36.7 to 62.8%, P < 0.05), mandibular lateral incisors (from 36.7 to 70.0%, P < 0.05), mandibular canines (from 31.7 to 53.3%, P < 0.05) and maxillary canines (from 30.0 to 55.0%, P < 0.05). While on the lingual side, it increased significantly in the maxillary central incisors (from 1.7 to 23.3%, P < 0.05), lateral incisors (from 6.7 to 38.3%, P < 0.05), and canines (from 21.7 to 46.7%, P < 0.05). The incidence of ABFs only increased on the labial side of the maxillary canines and mandibular central incisors. The occurrence of maxillary ABDs was strongly associated with the crowding (OR = 1.318, P = 0.007), while the occurrence of the mandibular ABDs was significantly associated with root surface (labial vs. lingual, OR = 1.836, P = 0.008).

CONCLUSIONS

The incidence of ABDs/ABFs significantly increased after non-extraction CAT with Class II elastics in adults, especially on the labial root surface of the mandibular anterior teeth. Orthodontists should be well aware of the periodontal risks of CAT with Class II elastics.

Effect of led photobiomodulation on tooth movement, gingival hypertrophy and pain in response to treatment with fixed orthodontic appliance

Photobiomodulation (PBM) is a form of treatment that uses low-power red and near-infrared light to stimulate tissue repair and regeneration at the cellular level. 32 subjects (198 teeth examined), 10 males and 22 females aged 14.6 ± 2.0 years, with mild dental crowding were included in a randomised, controlled clinical trial. The patients were treated with a fixed orthodontic appliance (FOA). Subjects were randomised into an experimental group (a PBM group irradiated with an LED light source with wavelengths of 625 nm, 660 nm and 850 nm simultaneously and an irradiance of 16 mW/cm²) and a placebo control group that received non-therapeutic irradiation with visible light. PBM therapy began within the first 2 days of appliance insertion and was administered twice weekly for 4 weeks. The rate of tooth movement (a change in distance at the same selected point on the occlusal plane of the tooth determined by measurements on 3D models), the presence of gingival hypertrophy (with a free gingival margin of at least 1 mm occlusal to the enamel-cement junction), the plaque index (PI), the sulcus bleeding index (SBI) and the subjective pain sensation using the visual analogue scale (VAS) were monitored. In the experimental PBM group (N = 14), the rate of movement with the FOA was statistically significantly higher at both 1 week of placement (0.5 mm [95%CI: 0.4-0.8]) and 4 weeks (1.1 mm [95%CI: 0.8-1.4]) than in the placebo group (N = 18), where the values were (0.4 mm [95%CI: 0.2-0.5]) at 1 week and (0.6 mm [95%CI: 0.4-0.9]) at 4 weeks. A lower incidence of gingival hypertrophy was observed in the PBM group (21.4%) than in the placebo group (55.6%) after 4 weeks (Mann-Whitney U-test, p < 0.05). PBM with LED accelerated orthodontic tooth movement during the levelling and alignment phase and reduced the incidence of gingival hypertrophy.

Pain and Tooth Movement During Orthodontic Leveling and Alignment-A Questionnaire-Based Study

Background: Orthodontic treatment with fixed appliances often induces pain. Despite existing research on pain management, the dynamic nature of orthodontic pain and its relationship with tooth movement remain underexplored. This study surveys adults under fixed appliance therapy to investigate pain dynamics, modifying factors, and perceived tooth movement, aiming to provide insights for improved patient care and treatment outcomes. Methods: This study focused on healthy individuals aged 18 to 50 undergoing fixed appliance treatment for up to six months after having braces bonded. A 24-question survey was administered over a one-month period. The survey explored pain intensity, pain dynamics, modifying factors, and perceived tooth movement. Results: Pain typically began within the first few hours after bonding and peaked the following day for most respondents. The upper incisors and molars were the most frequently reported areas of pain, corresponding to the teeth perceived as moving earliest. Chewing was identified as the primary external pain trigger. Gender significantly influenced pain perception, with women reporting higher pain levels and greater use of medication. The majority of participants managed without medication. Conclusions: Pain during the early phase of fixed appliance therapy follows a predictable pattern, with peak intensity occurring on the day after bonding. Pain perception strongly correlates with early tooth movement, particularly in the upper incisors. Gender differences were evident, but other demographic factors had minimal influence. Chewing was the primary pain aggravator, emphasizing the need for dietary modifications. Understanding these findings can help orthodontists develop personalized pain management strategies.

Effects of low-level laser irradiation on osteoclastogenesis in prostaglandin E2-stimulated macrophages

Low-level laser accelerates bone healing by regulating inflammation. In periodontal tissues, excessive mechanical stress induces alveolar bone resorption by producing excessive prostaglandin E2 (PGE2), which is an inflammatory agent that induces osteoclast differentiation. In this study, we aimed to investigate the effect of a low-energy Ga-Al-As diode laser (LLL) on PGE2-induced osteoclast differentiation of RAW264.7 (RAW) cells. RAW cells were stimulated with 10- 6 M PGE2 and irradiated with 810 nm LLL at 3.0 mW/cm2 for 10 min. After LLL stimulation, the cells were cultured for five days and subjected to tartrate-resistant acid phosphatase staining. Expression levels of the osteoclastogenesis-inducing factors, receptor activator of nuclear factor-κB ligand and nuclear factor of activated T cells 1 (NFATc1), were examined 24 and 48 h after PGE2 stimulation and LLL irradiation. Extracellular ATP concentration was determined 0, 1, 5, 10, and 20 min after PGE2 stimulation and LLL irradiation. Additionally, intracellular calcium concentration was measured as the fluorescence intensity of the cultured cells over time (20 s/scan) after 10 min of LLL irradiation. To investigate the nuclear translocation of NFATc1, the cells were fixed after 1 h of PGE2 stimulation and LLL irradiation and subjected to immunofluorescence analysis. The same experiments were performed using the P2 × 4 receptor (ATP-gated channel) antagonist, 5-BDBD. Small osteoclasts were observed in the LLL irradiation group. Receptor activator of nuclear factor-κB ligand and NFATc1 mRNA levels were not significantly different between the LLL-irradiated and non-irradiated groups. Extracellular ATP release and intracellular Ca2+ levels were increased by PGE2 stimulation but decreased by LLL irradiation and 5-BDBD treatment. Nuclear NFATc1 levels were also increased by PGE2 stimulation, but this effect was reversed by LLL irradiation and 5-BDBD treatment. Overall, our results suggest that LLL irradiation inhibits PGE2-induced osteoclast differentiation by inhibiting Ca2+-NFATc1 signaling via extracellular ATP release.

Effect of a self-ligating bracket system combined with corticision on the rate of orthodontic tooth movement: A controlled clinical trial

BACKGROUND

The self-ligating bracket system and corticision are two methods for acceleration of orthodontic tooth movement (OTM).

OBJECTIVES

The current study aimed to assess the effect of a self-ligating bracket system combined with corticision on the rate of OTM.

PATIENTS AND METHODS

The present study was conducted on 16 female patients divided into two groups: an experimental group of eight patients treated by self-ligating bracket systems used as fixed orthodontic appliances combined with a corticision as a minimally invasive surgical technique for accelerating OTM, and a control group of eight patients treated only by self-ligating bracket systems used as fixed orthodontic appliances. The primary outcome was the percentage of change in Little's Index of Irregularity (LII). The secondary outcome was the time taken to finish the leveling and alignment stage.

RESULTS

In a comparison of the percentage of change in LII for the upper arch between the two groups, the experimental group recorded values that were significantly greater than those recorded in the control group at all time intervals T0-T7, except for T8-T10, which were similar. Both groups recorded (100 ± 0%), with no significant difference between groups (P = 1).

CONCLUSION

The combination of two methods for acceleration of OTM, a self-ligating bracket system combined with corticision, accelerates the rate of OTM more than in the case of using a self-ligating bracket system only.

Proton-Nuclear Magnetic Resonance Metabolomics of Gingival Crevicular Fluid During Orthodontic Tooth Movement With Aligners

OBJECTIVES

To determine the correlation between orthodontic tooth movement and a pre-defined set of gingival crevicular fluid (GCF) metabolites through proton nuclear magnetic resonance (1H-NMR) spectroscopy.

MATERIALS AND METHODS

A clinical randomised prospective split-mouth study comparing the GCF metabolites around stationary and moving second maxillary molars. Twenty-four healthy subjects diagnosed with dental class II malocclusion undergoing orthodontic clear aligner treatment (CAT) were enrolled. GCF samples from the mesial and distal sulcus of second molars under stationary conditions or under 1 N of distalising force were harvested at baseline, 1 h, 7 days and 21 days after the application of CAT. 1H-NMR was utilised for GCF sample analysis. The 2-dimensional total correlation spectroscopy spectral signature of 35 known GCF metabolites was compared in moving and stationary teeth. Principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), variable importance in projection (VIP) score and area under the curve (AUC) were computed utilising MetaboAnalyst 5.0 software.

RESULTS

VIP-score values showed statistically significant differences between the metabolites involved in moving and stationary molars (p < 0.05). PCA and PLS-DA results showed potential differences between the metabolite clusters. The variation of the 1H-NMR signals of Glutamine, Uracil, N-Acetylneuraminate and alpha-ketoglutarate contributes primarily to the variance across metabolites in moving versus stationary teeth at 1 h, 7 days and 21 days.

CONCLUSION

High values of Glutamine and low values of Uracil, N-Acetylneurinamate and alpha-ketoglutarate could be utilised to predict the progress of orthodontic tooth movement over time. Knowledge of metabolites predictive of tooth movement could contribute to the design of tailored orthodontic treatment planning, reducing time, costs and side-effects.

Position and root resorption of the incisors following anterior segment retraction using friction versus frictionless mechanics: A randomised controlled trial

AIM

To evaluate the three-dimensional position and root resorption of incisors after anterior segment retraction (ASR) using friction versus frictionless mechanics.

PARTICIPANTS AND METHODS

Thirty female patients (13-18 years) with bimaxillary protrusion were randomly allocated into two groups. In the intervention group, ASR was undertaken using an elastomeric chain rendering 160 g/side extending between mini-screw implant and a hook crimped on 0.017 × 0.025-inch stainless-steel wire distal to the lateral incisor. In the comparison group, ASR was undertaken using closing T-loops fabricated from 0.017 × 0.025-inch titanium molybdenum alloy (TMA) wire rendering comparable retraction force. In both groups, the canine brackets were ligated after retraction to the mini-screw implants that were inserted in both the upper and lower arches bilaterally. The primary outcome was the three-dimensional changes in the position of the incisors. The secondary outcome was root resorption. These were measured from cone-beam computed tomography scans.

RESULTS

Statistically significant decreases in the upper (UI) and lower incisors (LI) crown torque were seen in both groups; however, the difference between groups was not statistically or clinically significant (UI MD -2.04°; 95% confidence interval [CI] = -8.02-3.95; LI MD -0.49°; 95% CI = -7.06-6.08). Significant tipping of upper (MD -1.17°; 95% CI = -2.06--0.27) and lower (MD -1.13°; 95% CI = -1.66--0.60) incisors was found in the friction, but not the frictionless group after retraction; however, the changes were not clinically significant. Significant lower incisor intrusion was found in both groups after retraction; however, the difference between groups was not statistically or clinically significant (MD -0.61°; 95% CI = -1.99-0.77). Statistically significant decreases in the UI and LI root length were seen in both groups. The difference between groups for UI changes was statistically significant (MD 0.54 mm; 95% CI = -0.02-1.07) but probably not clinically significant.

CONCLUSION

Considering the limitations in the current study, there was no advantage of either mechanics over the other regarding the final position of incisors. The likelihood of root resorption should be considered when frictionless mechanics are used for retraction of incisors.Registry:Clinicaltrials.gov (NCT04878939).

Deletion of kinin receptor B2 enhances orthodontic tooth movement and alveolar bone remodeling

The kallikrein-kinin system (KKS) is a complex enzymatic system involved in multiple biological processes, particularly inflammation. The system's peptides exert broad effects through two receptors, B1 (B1R) and B2 (B2R), expressed in various cell types, including osteoblasts. However, the impact of this system on bone remodeling induced by mechanical force needs to be better understood. This study aimed to elucidate the role of the B2 kinin receptor in bone phenotype and remodeling under mechanical stress. Orthodontic forces were applied to the upper first molars of B2R-/- mice and wild-type controls. Bone parameters, bone cellular counts, expression of inflammatory biomarkers, and osteoblast and osteoclast differentiation and activity were assessed using microtomography, histological analysis, real-time polymerase chain reaction (qPCR), and in vitro bone cell cultures, respectively. The results revealed that B2 receptor deficiency significantly altered maxillary bone architecture, reduced trabecular thickness, increased orthodontic tooth movement, and spontaneous alveolar bone loss (ABL). Histological analysis showed a higher number of osteoclasts in B2R-/- mice, with no significant change in osteoblast counts. Molecular analysis indicated elevated levels of RANK, RANKL, OPG, RANKL/OPG, IL-1β, and B1 receptor expression in B2R-/- mice, while in vitro studies confirmed enhanced osteoclast numbers and activity in B2R-/- cells. In conclusion, this study underscores the critical roles of kinin receptors in regulating alveolar bone remodeling, with B2R deletion leading to increased osteoclastic activity and bone loss. The compensatory upregulation of B1Rs in the absence of B2Rs suggests functional redundancy. However, the B2R-/- phenotype emphasizes the complex involvement of the KKS pathway in bone physiology, suggesting avenues for further research into bone pathophysiology and potential therapeutic approaches.

Human dental follicle stem cell-derived exosomes reduce root resorption by inhibiting periodontal ligament cell pyroptosis

BACKGROUND

To explore the therapeutic effects and mechanisms of the exosomes derived from dental follicle stem cells (DFSC-Exos) in reducing osteoclastogenesis and root resorption (RR) by inhibiting periodontal ligament cell (PDLC) pyroptosis.

METHODS

DFSC-Exos, with force stimulation (Force-Exos) or without (Ctrl-Exos), were co-cultured with human PDLCs in vitro and injected into the periodontal ligament (PDL) of rats following the establishment of RR models in vivo. Subsequently, resorption volume, PDLC pyroptotic ratio, and NLRP3-mediated pyroptosis pathway activation were performed to investigate the therapeutic effects of DFSC-Exos on PDLC pyroptosis during RR. Furthermore, the number of M1/M2 macrophages, osteoclast formation, and transwell polarization elucidated the role of Force-Exo treatment in macrophage polarization and osteoclastogenesis by inhibiting pyroptosis. Exosomal miRNA sequencing and bioinformatic analysis were used to identify differentially abundant exosome-derived miRNAs, as well as the dominant biological processes and pathways modulated by miRNA. The administration of miRNA inhibitors further verified the regulation of exosomal miRNA on RR via modulating pyroptosis. Moreover, the potential mechanisms involving candidate miRNAs and relevant pathways were explored.

RESULTS

Exosomes released by force-stimulated DFSCs (Force-Exos) inhibited NOD-like receptor 3 (NLRP3)-mediated PDLC pyroptosis, which impacted M1 macrophage activation and osteoclast formation. Based on exosomal miRNA sequencing, miR-140-3p in Force-Exos were transferred to PDLCs, and the administration of miR-140-3p inhibitors significantly reversed the reduction in PDLC pyroptosis, M1 macrophage polarization, osteoclast number, and resorption volume caused by Force-Exos. More importantly, mechanistic studies demonstrated that miR-140-3p mediated the function of Force-Exos by targeting DNA methyltransferase 1 (DNMT1) to alter the DNA methylation of suppressor of cytokine signaling (SOCS1) and the downstream nuclear factor κB (NF-κB) signaling pathway in PDLCs. Blocking the DNMT1/SOCS1/NFκB axis with DFSC-derived exosomal miR-140-3p downregulated NLRP3-mediated PDLC pyroptosis to impact M1 polarization and osteoclast formation, thereby alleviating RR.

CONCLUSION

DFSC-Exos downregulated NLRP3-mediated PDLC pyroptosis via miR-140-3p to block DNMT1/SOCS1/NFκB axis, which impacted M1 polarization and osteoclast formation, thereby alleviating RR.

Effect of Mechanical Force Stress on the Inflammatory Response in Human Periodontal Ligament Cells

Human periodontal ligament (hPDL) is continuously exposed to mechanical forces that can induce inflammatory responses in resident stem cells (hPDLSCs). Here, we review the impact of mechanical force on hPDLSCs, focusing on the activation of inflammatory cytokines and related signalling pathways, which subsequently influence periodontal tissue remodelling. The effects of various mechanical forces, including compressive, shear, and tensile forces, on hPDLSCs are discussed. The review highlights the role of pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α in mediating inflammatory responses, as well as the counteracting effects of anti-inflammatory cytokines like IL-4 and IL-10. Additionally, we underscore the involvement of toll-like receptors (TLRs), particularly TLR4, in transducing mechanical stress signals and modulating cytokine production. This review demonstrates that hPDLSCs respond to different mechanical forces with specific gene expression changes that direct inflammatory and bone remodelling signals, leading to increased osteoblast and osteoclast activity. Moreover, hPDLSCs, together with contiguous hPDL cells, respond to various mechanical forces by regulating the immune function of several immune cells. This complex relationship between the mechanical force stress, inflammation, and the cellular response in hPDLSCs warrants further research to develop therapeutic strategies for periodontal and related diseases.

MicroRNA functions in osteogenic differentiation of periodontal ligament stem cells: a scoping review

This scoping review aimed to describe the differential microRNA (miRNA) functions in osteogenic differentiation of periodontal ligament stem cells (PDLSCs), and then analyze the potential of applying PDLSCs and miRNAs in bone regeneration. The databases of PubMed, Google Scholar and EBSCO search were performed by the 4 themes, including periodontal ligament stem cells, miRNA, osteogenic differentiation, and tissue regeneration. The original articles described miRNA functions in osteogenic differentiation of PDLSCs were identified and selected for content analyze. The articles suggested that PDLSCs have high potential in bone regeneration because of their multipotency and immunomodulation. PDLSCs are conveniently accessible and obtained from extracted teeth. However, recent evidence reported that PDLSCs of various origins demonstrate differential characteristics of osteogenic differentiation. Exosomal miRNAs of PDLSCs demonstrate a regulatory role in tissue regeneration. The properties of PDLSCs associated to miRNA functions are altered in differential microenvironmental conditions such as infection, inflammation, high-glucose environment, or mechanical force. Therefore, these factors must be considered when inflamed PDLSCs are used for tissue regeneration. The results suggested inflammation-free PDLSCs harvested from the middle third of root surface provide the best osteogenic potential. Alternatively, the addition of miRNA as a bioactive molecule also increases the success of PDLSCs therapy to enhance their osteogenic differentiation. In conclusion, Exosome-derived miRNAs play a key role in PDLSCs osteogenic differentiation during tissue regeneration. While the success of PDLSCs in tissue regeneration could be uncertain by many factors, the use of miRNAs as an adjunct is beneficial for new bone regeneration.

Identification of Salivary Exosome-Derived miRNAs as Potential Biomarkers of Bone Remodeling During Orthodontic Tooth Movement

Orthodontic tooth movement (OTM) is a complex process involving bone remodeling, and is regulated by various molecular factors, including microRNAs (miRNAs). These small, non-coding RNAs are critical in post-transcriptional gene regulation and have been implicated in the modulation of osteoclast and osteoblast activity during OTM. This study aimed to explore the expression profiles of salivary exosome-derived miRNAs during OTM to identify potential biomarkers that could provide insights into the biological processes involved in orthodontic tooth movement. Saliva samples were collected from 15 patients at three time points: before treatment (Day 0), 7 days after the treatment's onset (Day 7), and 40 days after the treatment's onset (Day 40). The exosomes were isolated, and the miRNAs were extracted and sequenced. A differential expression analysis and gene ontology (GO) enrichment were performed to identify the miRNAs involved in osteoblast and osteoclast differentiation. Out of the 1405 detected miRNAs, 185 were analyzed. Several miRNAs were associated with bone-remodeling processes. The statistically significant finding was the downregulation of hsa-miR-4634 after 40 days of treatment. These findings contribute to the understanding of miRNA regulation in orthodontics and may have broader implications for skeletal disorders, such as osteoporosis.

A Novel Mechanics-Based Design for Overcorrection in Clear Aligner Orthodontics via Finite Element Analysis

A simplified mechanics model of aligner-tooth interaction was developed to establish a precise computational method for overcorrection design in clear aligner orthodontics. Validated through finite element analysis and experiments, the results demonstrated that designing the movement of only the target teeth on the aligner leads to uneven force distribution on adjacent teeth, while an overcorrection design can evenly distribute the reaction force generated by pushing the target teeth to the anchorage teeth, reducing the maximum force on the anchorage teeth, minimizing unplanned tooth movement, and improving the efficacy of the designed tooth movement for all teeth.

Periodontal response to nonsurgical accelerated orthodontic tooth movement

Tooth movement is a complex process involving the vascularization of the tissues, remodeling of the bone cells, and periodontal ligament fibroblasts under the hormonal and neuronal regulation mechanisms in response to mechanical force application. Therefore, it will inevitably impact periodontal tissues. Prolonged treatment can lead to adverse effects on teeth and periodontal tissues, prompting the development of various methods to reduce the length of orthodontic treatment. These methods are surgical or nonsurgical interventions applied simultaneously within the orthodontic treatment. The main target of nonsurgical approaches is modulating the response of the periodontal tissues to the orthodontic force. They stimulate osteoclasts and osteoclastic bone resorption in a controlled manner to facilitate tooth movement. Among various nonsurgical methods, the most promising clinical results have been achieved with photobiomodulation (PBM) therapy. Clinical data on electric/magnetic stimulation, pharmacologic administrations, and vibration forces indicate the need for further studies to improve their efficiency. This growing field will lead to a paradigm shift as we understand the biological response to these approaches and their adoption in clinical practice. This review will specifically focus on the impact of nonsurgical methods on periodontal tissues, providing a comprehensive understanding of this significant and understudied aspect of orthodontic care.

The IL-17 level in gingival crevicular fluid as an indicator of orthodontically induced inflammatory root resorption

PURPOSE

Interleukin (IL)-17 expression in the periodontal ligament is associated with orthodontically induced inflammatory root resorption (OIIRR). Seeking a convenient, rapid, and non-invasive IL-17 detection approach could help predict OIIRR. In this study, we assessed the potential of the IL-17 level in gingival crevicular fluid (GCF) to be an indicator of OIIRR.

METHODS

To enable tooth movement, 8‑ to 10-week-old male Wistar rats were subjected to 20 g/60 g orthodontic force for up to 14 days. GCF and peripheral blood were collected for the IL-17 enzyme-linked immunosorbent assay (ELISA). Histological changes and the expression of IL-17, receptor activator of nuclear factor κB ligand (RANKL), and osteoprotegerin (OPG) in periodontal tissue were evaluated by hematoxylin-eosin and immunohistochemistry staining, respectively. Osteoclasts were visualized by tartrate-resistant acid phosphatase (TARP) staining.

RESULTS

GCF IL-17 level rapidly rose in the early phase of orthodontic loading, accompanied by bone and tooth root destruction. At the later stage, the GCF IL-17 level gradually decreased, while the inflammatory destruction was reduced and the periodontal tissue began to repair. GCF IL-17 expression generally tended to be coincident with the periodontal tissue reaction: GCF IL-17 was robustly correlated to the RANKL/OPG ratio (rs = 0.72, p = 0.002) or osteoclast number (rs = 0.84, p < 0.001). Additionally, the GCF IL-17 level was correlated to serum IL-17 (rs = 0.61, p = 0.016) or periodontal IL-17 (rs = 0.84, p < 0.001).

CONCLUSION

The IL-17 level in GCF during orthodontic treatment is associated with OIIRR and, thus, could be an early indicator for developing OIIRR. The advantages of being a convenient, rapid, and non-invasive GCF IL-17 measurement make it a promising method for early detection of OIIRR.

Alendronate partially rescues the periodontal defects in OIM mouse model of osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a fairly common generalized connective disorder characterized by low bone mass, bone deformities and impaired bone quality that predisposes affected individuals to musculoskeletal fragility. Periodontal ligament (PDL)-alveolar bone and PDL-cementum entheses' roles under OI conditions during physiological loading and orthodontic forces remain largely unknown. In addition, bisphosphonates (e.g., alendronate) are commonly used therapeutics for the treatment of OI. Our knowledge, in terms of the affects of alendronate treatment on the PDL entheses in OI is also far from complete. In this study, we identified craniofacial skeletal defects in an osteogenesis imperfecta (oim) murine model of OI. Relative to wild-type littermates, oim mice were found to have decreased skull length, cranial height/width/length, nose length, nasal length, and frontal length. Next, we discovered that oim mice exhibited defects in several dental structures, including short roots and decreased volumes of the alveolar bone, dentin, and cellular cementum. Further, we specifically investigated periodontal defects in the oim mice. Alveolar bone loss in oim mice was primarily associated with elevated bone resorption due to an increased osteoclast number, along with reduced bone formation related to increased sclerostin (SOST) expression. PDL fibers in oim mice were disrupted and discontinuous, while Sharpey's fibers at the PDL-bone entheses were reduced. Mechanism-based studies showed that catabolism of the PDL was elevated in oim mice, as revealed by an increase in MMP13 and CTSK expression. Meanwhile, the quality of the collagen fibers were impaired in oim mice due to a large accumulation of uncleaved collagen I fibers. With alendronate treatment, however, we could partially rescue these phenotypes. This study, for the first time, characterized periodontal defects in oim mice, detailed craniofacial defects and demonstrated the effectiveness of alendronate in partially restoring these defects.

Endo 180 participates in collagen remodeling of the periodontal ligament during orthodontic tooth movement

BACKGROUND

Orthodontic tooth movement (OTM) relies on the remodeling of periodontal tissues, including the periodontal ligament (PDL) and alveolar bone. Collagen remodeling plays a crucial role during this process, allowing for the necessary changes in the PDL's structure and function. Endo180, an urokinase plasminogen activator receptor-associated protein, is a transmembrane receptor regulated collagen remodeling. This study aims to investigate whether and how Endo180 participates in collagen remodeling within the PDL during OTM.

MATERIALS AND METHODS

A mechanical force-induced OTM rat model was established using a closed coiled spring to mesially move the right maxillary first molar. The distance of OTM was examined by micro-computed tomography (micro-CT). The collagen remodeling within the PDL was assessed using atomic force microscope (AFM), Hematoxylin-Eosin (HE) staining and Masson staining. Protein expressions of Endo180, collagen I (COL I) and collagen III (COL III) were analyzed via immunofluorescence staining. Additionally, the mRNA expressions of Endo180, COL I, and COL III in force-induced PDL cells were examined by RT-qPCR in vitro. To further illustrate the role of Endo180 in regulating COL I and COL III expressions, Endo180 siRNA (siEndo) was applied to force-stimulated PDL cells.

RESULTS

Force application increased OTM distance and disrupted collagen fiber organization, with a greater decrease in collagen elastic modulus on the mesial side than on the distal side of the PDL. After 7 days of force application, Endo180 and COL III expressions significantly increased in PDL tissues, while COL I expression decreased in PDL tissues. Compressive force loading in vitro upregulated the mRNA expressions of Endo180 and COL III, but downregulated COL I mRNA expression. Notably, Endo180 knockdown using siRNA suppressed force-induced COL III expression while restoring the downregulated COL I expression under compressive force stimuli.

CONCLUSION

Force-induced Endo180 expression modulates collagen remodeling in PDL during OTM by upregulating COL III and downregulating COL I. This collagen reorganization facilitates efficient tooth movement, highlighting Endo180 as a potential therapeutic target to optimize orthodontic treatment outcomes.

Inflammation and mechanical force-induced bone remodeling

Periodontitis arises from imbalanced host-microbe interactions, leading to dysbiosis and destructive inflammation. The host's innate and adaptive immune responses produce pro-inflammatory mediators that stimulate destructive events, which cause loss of alveolar bone and connective tissue attachment. There is no consensus on the factors that lead to a conversion from gingivitis to periodontitis, but one possibility is the proximity of the inflammation to the bone, which promotes bone resorption and inhibits subsequent bone formation during coupled bone formation. Conversely, orthodontic tooth movement is triggered by the mechanical force applied to the tooth, resulting in bone resorption on the compression side and new bone formation on the tension side. However, the environment around orthodontic brackets readily retains dental plaque and may contribute to inflammation and bone remodeling. The immune, epithelial, stromal, endothelial and bone cells of the host play an important role in setting the stage for bone remodeling that occurs in both periodontitis and orthodontic tooth movement. Recent advancements in single-cell RNA sequencing have provided new insights into the roles and interactions of different cell types in response to challenges. In this review, we meticulously examine the functions of key cell types such as keratinocytes, leukocytes, stromal cells, osteocytes, osteoblasts, and osteoclasts involved in inflammation- and mechanical force-driven bone remodeling. Moreover, we explore the combined effects of these two conditions: mechanical force-induced bone remodeling combined with periodontal disease (chronic inflammation) and periodontally accelerated osteogenic orthodontics (acute transient inflammation). This comprehensive review enhances our understanding of inflammation- and mechanical force-induced bone remodeling.

Adult-onset hypophosphatasia diagnosed after consecutive tooth loss during orthodontic treatment: a case report

BACKGROUND

Adult hypophosphatasia is an uncommon inherited disorder of mineral homeostasis affecting bone. It arises from mutations within the Alkaline Phosphatase, Biomineralization Associated (ALPL) gene, which encodes tissue-nonspecific alkaline phosphatase. Because of its low prevalence and non-specific clinical manifestations, underdiagnosis and misdiagnosis are frequent, particularly in Asian populations.

CASE PRESENTATION

We present a case of a 38-year-old Japanese male diagnosed with adult hypophosphatasia following consecutive tooth loss during orthodontic treatment. Genetic analysis revealed a compound heterozygous mutation within the ALPL gene. The patient remained asymptomatic until orthodontic treatment, suggesting that increased mechanical stress overwhelmed residual enzyme activity, triggering the hypophosphatasia symptoms. Asfotase Alfa enzyme replacement therapy improved healing following tooth extraction.

CONCLUSION

This case highlights the significance of including adult hypophosphatasia in the differential diagnosis for obscure dental complications arising during orthodontic procedures, particularly in Asian patients where certain ALPL variants may be more prevalent. Effective diagnosis and management of adult hypophosphatasia necessitate collaboration between orthodontic practitioners and medical specialists. Improved awareness and a multidisciplinary approach are crucial for timely diagnosis and successful intervention.

The Potential Regulatory Role of Ferroptosis in Orthodontically Induced Inflammatory Root Resorption

People, in increasing numbers, are seeking orthodontic treatment to correct malocclusion, while some of them are suffering from orthodontically induced inflammatory root resorption (OIIRR). Recent evidence suggests that the immune-inflammatory response occurring during bone remodeling may be responsible for OIIRR. Ferroptosis, a new type of programmed cell death (PCD), has been found to have a close interrelation with inflammation during disease progression. While ferroptosis has been extensively studied in bone-related diseases, its role in OIIRR is poorly understood. Considering that the tooth root shares a lot of similar characteristics with bone, it is reasonable to hypothesize that ferroptosis contributes to the development of OIIRR. Nevertheless, direct evidence supporting this theory is currently lacking. In this review, we introduced ferroptosis and elucidated the mechanisms underlying orthodontic tooth movement (OTM) and OIIRR, with a special focus on the pivotal role inflammation plays in these processes. Additionally, we covered recent research exploring the connections between inflammation and ferroptosis. Lastly, we emphasized the important regulatory function of ferroptosis in bone homeostasis. Further investigations are required to clarify the modulation mechanisms of ferroptosis in OIIRR and to develop novel and potential therapeutic strategies for the management of OIIRR.

Evaluation of pulpal blood flow during orthodontic space closure: Prospective clinical trial

INTRODUCTION

Orthodontic tooth movement (OTM) is a biological process that can affect the vascularization of the dental pulp. The forces exerted on the teeth may increase periapical pressure that could compress the arterioles, which in turn affects pulpal blood flow (PBF). The study aimed to investigate how OTM affects PBF during orthodontic space closure.

METHODS

A total of 22 adolescent participants who required orthodontic space closure in mandibular posterior sectors were enrolled in a prospective clinical study. The same sliding mechanics, wires, and active elements were used. Patients were observed before OTM, after leveling before space closure, and at the 4th, 7th, 21st, and 28th during active space closure. PBF was measured with laser Doppler (LD) flowmetry. Dental models were obtained with an intraoral scanner.

RESULTS

The LD flow values decreased significantly during the observation period (2-way repeated measures analysis of variance, P <0.001). There was a significant difference in LD flow between tooth categories (2-way repeated measures analysis of variance, P <0.001). During space closure, the most pronounced LD flow reduction was observed in single-rooted teeth closest to the residual space. A higher speed of OTM was associated with a greater decrease in LD flow on day 4 of OTM (Pearson correlation, P = 0.0299).

CONCLUSIONS

Orthodontic space closure reduced PBF; it was lowest in the early stages of space closure and showed a tendency to increase during the first month. Anterior teeth closer to the interdental space that experiences more OTM and teeth that move faster during initial OTM had a higher risk of reduced blood flow.

Effects of wearing fixed orthodontic appliance on dynamic balance, reaction time, and pain perception in adolescents and young adult elite athletes

OBJECTIVE

To investigate the effects of using fixed orthodontic appliance on dynamic balance, auditory/visual reaction times, as well as pain perception in adolescent and young adult elite athletes.

METHODS

A total of 34 elite athletes (n = 19 males) aged 16-21 years from different sports (track and field sprint, long jump and discus throw) were randomly allocated to treatment (n = 17) or control (n = 17) groups. The treatment group received self-ligating brackets with 0.04 cm super-elastic nickel-titanium arch wire, placed in the brackets to correct the teeth position. Perceived pain (i.e., visual analogue scale), dynamic balance (i.e., Y balance test), and auditory reaction time and visual reaction time using Direct RT software were assessed before (day-1), and on five occasions after fixed orthodontic appliance placement (day+1, +3, +7, +14, and +30). The two groups' quantitative data [expressed as mean (standard deviation)] for each occasion were compared using the Student's t-test. Comparisons of the Y-balance test, auditory reaction time, visual reaction time, and pain visual analogue scale data were each made between the 6 occasions via a factorial A × B analysis of variance in order to check for the possible interaction between the two groups and the (6) consecutive days (occasions).

RESULTS

Compared to the control group, the treatment group showed significantly (i) lower values of anterior reach for both the dominant ([78(4) vs. 75(3)%, respectively]) and the non-dominant [76(3) vs. 74(4)%, respectively] legs at day+3, and (ii) higher values of pain visual analogue scale at day+1, day+3, and day+7 [0.00(0.00) vs. 4.94(1.25); 0.00(0.00) vs. 4.12(1.17), and 0.00(0.00) vs. 0.41(0.51), respectively). Factorial analysis of variance revealed that only pain visual analogue scale values were different between the two groups at day+1 and day+3.

CONCLUSION

FOA induced a high pain level during the first week following its placement in elite athletes.

How does orthodontic tooth movement influence the dental pulp? RNA-sequencing on human premolars

OBJECTIVES

The objective of this study is to analyse the gene expression profile of the dental pulp (DP) of human premolars subjected to 7 and 28 days of orthodontic force (OF) in vivo by using RNA sequencing. The maxillary and mandibular DP were additionally compared.

METHODS

Healthy patients requiring orthodontic premolar extractions were randomly assigned to one of the three groups: control (CG) where no OF was applied, 7 and 28 days, where premolars were extracted either 7 or 28 days after the application of a 50-100 g OF. Total RNA was extracted from the DP and analysed via RNA-seq. Differentially expressed genes (DEGs) were identified using a false discovery rate and fold change threshold of <0.05 and ≥1.5, respectively. Functional analysis was performed.

RESULTS

After 7 days of OF, pulp reaction indicates immune response, hypoxia, DNA damage and epigenetic regulation. After 28 days, cell adhesion, migration, organization and tissue repair are evident. The maxillary and mandibular pulp tissues react differently to OF. The maxilla exhibits minimal alterations, mostly related to immune response at 7 days and tissue repair at 28 days, whereas the mandible shows mostly DNA damage and epigenetic regulation at 7 days and return to the original state at 28 days.

CONCLUSIONS

This study demonstrates that the early reaction of the DP to OF is marked by immune response, hypoxia and DNA damage. In contrast, after 28 days, cell adhesion, migration, organization, tissue repair and dentine formation are observed. Maxillary and mandibular premolars react differently to OF: although the maxilla exhibits minimal alterations at both time points, the mandible mostly shows DNA damage, epigenetic regulation, and immune response at 7 days. These disparities could stem from different blood supplies or the lower maxillary bone density, potentially triggering faster biological changes. Our findings provide insights into the gene regulatory networks modulating DP response to OF.

Changes in the Periodontal Gap After Long-Term Tooth Movement into Augmented Critical-Sized Defects in the Jaws of Beagle Dogs

Background/Objectives: Extensive and closely coordinated remodeling processes take place in the periodontal ligament (PDL) and the adjacent bone during orthodontic tooth movement. In complex orthodontic cases, it is necessary to move teeth into an augmented bony defect, for example, in patients with cleft lip, alveolus, and palate. The important role of the PDL during tooth movement is well accepted but not fully understood. Therefore, the present study investigated the PDL after 23 weeks of tooth movement into an augmented critical-sized defect. Methods: The second molars of four beagle dogs were moved into a critical-sized defect, which was filled with bovine xenograft or nanocrystalline hydroxyapatite. Autogenous bone served as control. After 23 weeks, histological samples were microscopically analyzed, and the dimension of the PDL was measured. For statistical calculations, a Wilcoxon-Mann-Whitney test was used. Results: The PDL was significantly wider on the tension side compared with the compression side for all replacement materials analyzed (p ≤ 0.05). These results apply to both the mesial and distal roots. Conclusions: The remodeling processes reached equilibrium within 23 weeks, resulting in a wider gap on the tension side, which contrasts with the situation a few days after the initial force application.

Effect of photobiomodulation and corticopuncture methods on tooth displacement and gene expression: animal study

AIM

The aim of this study was to evaluate the expression levels of vascular endothelial growth factor (VEGF), Peroxiredoxin 1 (PRX1), glucose transporter 1 (GLUT1) and type I collagen (COL1) and the rate of tooth movement comparing 3 accelerated tooth movement (ATM) methods: Corticopuncture (CP), photobiomodulation (PBM) and the combined technique (CP + PBM) on days 1, 3, 7 and 14.

METHODS

Orthodontic tooth movement was induced in 24 male Wistar rats. CP procedure included three perforations: two in the palate and one mesial to the molars. GaAlAs diode laser irradiation was performed on days 0, 2, 4 and 6, totaling 4 irradiations. 14 days (810 nm, 100 mW, 15 s). Gingival tissue was collected from the cervical area of both first molars and qPCR was performed to isolate and quantify mRNA levels.

RESULTS

All ATM groups showed increased tooth displacement compared to control after 14 days (20% for PBM; 40% for CP and 60% for CP + PBM). PBM showed higher VEGF expression on days 1,3 and 7 followed by CP and CP + PBM. PRX1 levels increased on days 1 and 3 in PBM and CP + PBM. GLUT1 increased on day 3 in all groups. No difference was found on levels of VEGF, PRX1 and GLUT1 among the groups on day 14, except for COL1 which increased significantly in PBM group.

CONCLUSION

All ATM methods showed higher expression of all of VEGF, PRX1, GLUT1, COL1 than control group. PBM and CP + PBM groups had more expression related to angiogenesis, glucose uptake, oxidative stress and collagen synthesis.

Development of a Custom Fluid Flow Chamber for Investigating the Effects of Shear Stress on Periodontal Ligament Cells

The periodontal ligament (PDL) is crucial for maintaining the integrity and functionality of tooth-supporting structures. Mechanical forces applied to the tooth during orthodontic tooth movement generate pore pressure gradients, leading to interstitial fluid movement within the PDL. The generated fluid shear stress (FSS) stimulates the remodeling of PDL and alveolar bone. Herein, we present the construction of a parallel fluid-flow apparatus to determine the effect of FSS on PDL cells. The chamber was designed and optimized using computer-aided and computational fluid dynamics software. The chamber was formed by PDMS using a negative molding technique. hPDLCs from two donors were seeded on microscopic slides and exposed to FSS of 6 dyn/cm2 for 1 h. The effect of FSS on gene and protein expression was determined using RT-qPCR and Western blot. FSS upregulated genes responsible for mechanosensing (FOS), tissue formation (RUNX2, VEGFA), and inflammation (PTGS2/COX2, CXCL8/IL8, IL6) in both donors, with donor 2 showing higher gene upregulation. Protein expression of PTGS2/COX2 was higher in donor 2 but not in donor 1. RUNX2 protein was not expressed in either donor after FSS. In summary, FSS is crucial in regulating gene expression linked to PDL remodeling and inflammation, with donor variability potentially affecting outcomes.

Periodontal Ligament Reactions to Orthodontic Force: A Transcriptomic Study on Maxillary and Mandibular Human Premolars

AIMS

Orthodontic force (OF) induces a variety of reactions in the periodontal ligament (PDL) that could potentially account for individual variability regarding orthodontic tooth movement (OTM). This study investigates the transcriptomic profile of human PDL tissue subjected to OF in vivo for 7 and 28 days, additionally comparing the differences between maxillary and mandibular PDL.

METHODS

Healthy patients requiring orthodontic premolar extractions were randomly assigned to one of three groups: control (CG) where no OF was applied, 7 days and 28 days, where premolars were extracted either 7 or 28 days after the application of a 50-100 g OF. Total RNA was extracted from the PDL tissue and analyzed via RNA-seq. Differentially expressed genes (DEGs) were identified using a false discovery rate and fold change threshold of < 0.05 and ≥ 1.5 respectively. Functional and Protein-Protein Interaction analysis were performed.

RESULTS

After 7 days of OF, the reaction of PDL to OF is characterized by cell responses to stress, increased bone resorption, inflammation and immune response, and decreased bone formation. In contrast, after 28 days, bone regeneration is more prominent, and processes of bone homeostasis, immune response, and cell migration are present. The response of maxillary and mandibular PDL was different. Bone resorption was observed in the maxilla at 7 and 28 days, while in the mandible expression of cell proliferation and transcriptional activity were predominant after 28 days of OF.

CONCLUSIONS

The early reaction of the PDL to OF corresponds with increased bone resorption and decreased bone formation. After 28 days, bone formation became more prominent. The maxillary and mandibular PDL present asynchronous responses during OTM. These findings enhance our comprehension of the mechanisms underlying the origin-specific responses of PDL to different lengths of OF, which is potentially relevant in the development of personalized therapeutic strategies.

Breaking a dogma: orthodontic tooth movement alters systemic immunity

BACKGROUND

The prevailing paradigm posits orthodontic tooth movement (OTM) as primarily a localized inflammatory process. In this study, we endeavor to elucidate the potential ramifications of mechanical force on systemic immunity, employing a time-dependent approach.

MATERIALS AND METHODS

A previously described mouse orthodontic model was used. Ni-Ti. springs were set to move the upper 1st-molar in C57BL/6 mice and the amount of OTM was. measured by µCT. Mice were allocated randomly into four experimental groups, each. corresponding to clinical phases of OTM, relative to force application. Terminal blood. samples were collected and a comprehensive blood count test for 7 cell types as well as. proteome profiling of 111 pivotal cytokines and chemokines were conducted. Two controls. groups were included: one comprised non-treated mice and the other mice with inactivated springs.

RESULTS

Serum immuno-profiling unveiled alterations in cellular immunity, manifesting as. changes in percentages of leukocytes, monocytes, macrophages, neutrophils, and. lymphocytes, alongside key signaling factors in comparison to both control groups. The systemic cellular and molecular alterations triggered by OTM mirrored the dynamics previously described in the local immune response.

CONCLUSIONS

Although the exact interplay between local and systemic immune responses to orthodontic forces require further elucidation, our findings demonstrate a tangible link between the two. Future investigations should aim to correlate these results with human subjects, and strive to delve deeper into the specific mechanisms by which mechanical force modulates the systemic immune response.

Micro-osteoperforation for enhancement of orthodontic movement: A mechanical analysis using the finite element method

BACKGROUND

Micro-osteoperforation is a minimally invasive technique aimed at accelerating tooth movement. The goal of this novel experimental study was to assess tooth movement and stress distribution produced by the force of orthodontic movement on the tooth structure, periodontal ligament, and maxillary bone structure, with and without micro-osteoperforation, using the finite element method.

MATERIALS AND METHODS

Cone-beam computed tomography was used to obtain a virtual model of the maxilla and simulate the extraction of right and left first premolars. Three micro-osteoperforations (1.5 x 5 mm) were made in the hemiarch on the distal and mesial surfaces of upper canines, according to the power tip geometry of the Propel device (Propel Orthodontics, Ossining, New York, USA). An isotropic model of the maxilla was fabricated according to the finite element method by insertion of mechanical properties of the tooth structures, with orthodontic force (1.5 N) simulation in the distal movement on the upper canine of a hemiarch.

RESULTS

Initial movement was larger when micro-osteoperforations were performed on the dental crown (24%) and on the periodontal ligament (29%). In addition, stress distribution was higher on the bone structure (31%) when micro-osteoperforations were used.

CONCLUSIONS

Micro-osteoperforations considerably increased the movement of both the dental crown and periodontal ligament, which highlights their importance in the improvement of orthodontic movement, as well as in stress distribution across the bone structure. Important stress absorption regions were identified within micro-osteoperforations.

TNF reduces osteogenic cell fate in PDL cells at transcriptional and functional levels without alteration of periodontal proliferative capacity

AIMS

To investigate the effect of tumor necrosis factor (TNF) on the growth of human periodontal ligament (PDL) cells, their osteogenic differentiation and modulation of their matrix secretion in vitro.

METHODS

The influence of 10 ng/ml TNF on proliferation and metabolic activity of PDL cells was analyzed by cell counting (DAPI [4',6-diamidino-2-phenylindole] staining) and the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. In addition, cells were cultured under control conditions and osteogenic conditions (media containing 10 mM β-glycerophosphate). Quantitative expression analysis of genes encoding the osteogenic markers alkaline phosphatase (ALP), collagen type I alpha 1 chain (COL1A1), osteoprotegerin (OPG), and osteopontin (OPN) was performed after 7 and 14 days of cultivation. Calcium deposits were stained with alizarin red.

RESULTS

Our studies showed that 10 ng/ml TNF did not affect the survival and metabolic activity of PDL cells. Quantitative expression analysis revealed that long-term cultures with TNF impaired osteogenic cell fate at early and late developmental stages. Furthermore, TNF significantly reduced matrix secretion in PDL cells.

CONCLUSION

The present data confirm TNF as a regulatory factor of proinflammatory remodeling that influences the differentiation behavior but not the metabolism and cell proliferation of the periodontium. Therefore, TNF represents an interesting target for the regulation of orthodontic remodeling processes in the periodontium.

Validation of reliable reference genes for qPCR of CD4+ T cells exposed to compressive strain

For accurate interpretation of quantitative real-time PCR (qPCR) data, stable reference genes are essential for normalization of target genes. To date, there is no information on reliable housekeeping genes in CD4+ T cells in a three-dimensional (3D) matrix under pressure stimulation. This in vitro study describes for the first time a method for pressure stimulation of CD4+ T cells in a 3D matrix in the context of orthodontic tooth movement (OTM) and identifies a set of reliable reference genes. CD4+ T cells were isolated from murine spleen and activated with anti-CD3/-CD28 Dynabeads (Thermo Fisher, Langenselbold, Germany) on standard cell culture plates or in 3D scaffolds with or without compressive strain. Expression stability of nine potential reference genes was examined using four mathematical algorithms. Gene expression of Il2 was normalized to all potential reference genes to highlight the importance of correct normalization. Cell proliferation and the expression of the surface markers CD25 and CD69 were also determined. The 3D matrix did not inhibit proliferation after immunological activation of T cells and embedded the cells sufficiently to expose them to pressure load. Expression of ubiquitin C (Ubc) and hypoxanthine phosphoribosyltransferase (Hprt) was the most stable under all conditions tested. A combination of these two genes was suitable for normalization of qPCR data. Normalization of Il2 gene expression showed highly variable results depending on the reference gene used. Pressure reduced cell proliferation and the number of CD69-positive T cells. This study provides a basis for performing valid and reliable qPCR experiments with CD4+ T cells cultured in 3D scaffolds and exposed to compressive forces simulating OTM.

Exploring biological mechanisms in orthodontic tooth movement: Bridging the gap between basic research experiments and clinical applications - A comprehensive review

OBJECTIVES

The molecular mechanisms behind orthodontic tooth movements (OTM) were investigated by clarifying the role of chemical messengers released by cells.

METHODS

Using the Cochrane library, Google scholar, and PubMed databases, a literature search was conducted, and studies published from 1984 to 2024 were considered.

RESULTS

Both bone growth and remodeling may occur when a tooth is subjected to mechanical stress. These chemicals have a significant effect on the stimulation and regulation of osteoblasts, osteoclasts, and osteocytes during alveolar bone remodeling. This regulation can take place in pathological conditions, such as periodontal diseases, or during OTM alone. This comprehensive review outlines key molecular mechanisms underlying OTM and explores various clinical assumptions associated with specific molecules and their functional domains during this process. Furthermore, clinical applications of certain molecules such as relaxin, prostaglandin E (PGE), and interleukin-1β (IL-1β) in accelerating OTM have been reported. Our findings underscore the existing gap between OTM clinical applications and basic research investigations.

CONCLUSION

A comprehensive understanding of orthodontic treatment is enriched by insights into biological systems. We reported the activation of osteoblasts, osteoclast precursor cells, osteoclasts, and osteocytes in response to mechanical stress, leading to targeted cellular and molecular interventions and facilitating rapid and regulated alveolar bone remodeling during tooth movement. Despite the shortcomings of clinical studies in accelerating OTM, this review highlights the crucial role of biological agents in this process and advocates for prioritizing high-quality human studies in future research to gain further insights from clinical trials.

Stress Analysis of Periodontal Tissue in en Masse Retraction With Integration of Maxillary Anterior Teeth: A Three-Dimensional Finite Element Method Study

OBJECTIVE

To simulate the en masse traction technique with the integration (EMTI) of six maxillary anterior teeth using a finite element model (FEM) and explore various protocols for maxillary protrusion. The study aimed to investigate root displacement and stress distribution in the periodontal ligament (PDL) by varying the retraction position and direction of EMTI applied to the maxillary anterior teeth. No actual participants were involved.

MATERIALS AND METHODS

The FEM model included six teeth (central and lateral incisors and canines) with a PDL thickness of 0.3 mm. The model encompassing the alveolar bone (ALB) and EMTI had 180,528 elements and 47,836 nodes. The EMTI integrated six anterior teeth via a 0.9-mm-diameter stainless steel lingual wire, equipped with three moment arms extending toward the root apex: one midline (central arm) and two distal to the canines (lateral arms). The position and direction of the traction force applied to the three moment arms of the EMTI were varied to assess crown and apex displacement, as well as PDL stress.

RESULTS

Lingual tipping was consistent across all protocols, emphasizing controlled incisor tipping. The application of horizontal traction at 10 mm and traction at 7 mm from the central and lateral arms of the EMTI, respectively, demonstrated the most uniform stress distribution across the PDL of all six anterior teeth.

CONCLUSIONS AND CLINICAL SIGNIFICANCE

The FEM analysis results suggest that the new EMTI method, which retracts the maxillary anterior teeth as a unit, is effective for tooth movement and PDL stress distribution. The EMTI technique, with its specific traction protocols and emphasis on controlled tipping, appears to be a promising approach for addressing maxillary protrusions.

Changes in the alveolar bone morphology among different patterns of incisor inclination during the alignment phase in orthodontic treatment without premolar extraction

OBJECTIVE

The present study investigated bone remodelling in the upper and lower incisor regions depending on the inclination pattern during the alignment phase of orthodontic treatment (OT).

MATERIALS AND METHODS

This prospective clinical study included 71 patients undergoing OT without premolar extraction. Cone beam computed tomography scans were taken before and after the alignment phase and the changes in the inclination, alveolar bone height (ABH) and bone thickness (BT) at levels 2, 3, 4, 6, 8 and 9 mm starting from the cementoenamel junction (CEJ) were determined.

RESULTS

Teeth were divided into 'Retroinclination' (lingual crown inclination <0°), 'Proclination-low' (buccal crown inclination between 0° and 5°), or 'Proclination-high' (buccal crown inclination >5°). The alignment phase of OT resulted in ABH loss. The highest ABH loss in the maxilla was observed on the buccal side in the 'Proclination-high' and was 0.71 mm. ABH loss by 1.1 mm was observed in the mandible on the lingual side in the 'Retroinclination' group. The most significant changes in BT by up to 2 mm were observed at levels 6, 8 and 9 mm and these changes exhibited a moderate to strong correlation with the alterations in the inclination of individual incisors. At levels 2, 3 and 4 mm, the highest decrease in BT by up to 0.83 mm was observed on the palatal side of upper incisors in the 'Proclination-high' group.

CONCLUSION

The direction and amount of tooth inclination partially determine changes in the bone parameters during the alignment phase.

Evaluation of Biomarkers of Bone Metabolism on Salivary Matrix in the Remodeling of Periodontal Tissue during Orthodontic Treatment

The aim of this study was to evaluate changes in the concentration of N-terminal type I collagen extension pro-peptide (PINP), tartrate-resistant acid phosphatase (TRAcP), and parathyroid hormone-related protein (PTHrP) in saliva during orthodontic treatment in order to evaluate whether changes in bone turnover marker (BTM) concentration can help highlight the effects of orthodontic mechanical loading in the absence of clinical evidence of tooth movement in terms of tooth movement. Saliva samples from 25 apparently healthy young subjects (10 females and 15 males) were collected using Salivette® (Sarstedt) with cotton swabs and the concentrations of PTHrP, TRAcP 5b, and PINP were analyzed at time 0 (T1), 25 days (T2), and at 45 days (T3). Differences in the median value of biomarker levels between baseline T1 and follow-up of the different groups (T2 and T3) were assessed using the non-parametric Mann-Whitney U test. Trough concentrations of P1NP, PTHrP, and TRAcP were 0.80 µg/L, 0.21 ng/mL, and 0.90 U/L above the method LOD. The non-parametric Mann-Whitney U test confirmed a statistically significant difference in T1 versus concentrations of T2 and T3. All subjects evaluated had a statistically significant difference between T1 vs. T3. when compared with the specific critical difference (RCV) for the analyte The results obtained demonstrate that the evaluation of BTM changes in saliva can help the evaluation of orthodontic procedures and the monitoring of biomechanical therapy.

Evaluation of Pain and Discomfort Associated with Orthodontic Adjustments

Background

Orthodontic treatment is commonly associated with pain and discomfort, impacting patient experience and treatment compliance. Understanding the factors influencing pain perception is crucial for improving pain management strategies during orthodontic adjustments.

Methods

Pain levels were assessed using a "Visual Analog Scale (VAS)" before and after each adjustment session. Qualitative data were collected through semi-structured interviews conducted immediately post-adjustment. Statistical analyses were performed to compare mean pain scores before and after adjustments, and thematic analysis was conducted to identify common themes in qualitative data.

Results

Quantitative analysis revealed a significant increase in mean pain scores following orthodontic adjustments (P < 0.001). Qualitative analysis identified themes related to pain experiences, including anticipation of discomfort, adaptation over time, and coping strategies employed by patients.

Conclusion

Orthodontic adjustments induce varying levels of pain and discomfort among patients. By integrating quantitative and qualitative assessments, this study provides comprehensive insights into patient experiences during orthodontic treatment, informing strategies for pain management and patient care.

A Comparative Analysis of Alkaline Phosphatase Levels in Gingival Crevicular Fluid of Patients Undergoing Growth Modulation Therapy With Twin Block, Forsus Fatigue Resistant, and Clear Block Appliances Compared to Normal Individuals: An In Vivo Study

Background In the contemporary era, where science and technology know no boundaries, this in vivo study explores the impact of growth modulation therapy using Twin Block, Forsus Fatigue Resistant, and Clear Block appliances on alkaline phosphatase (ALP) levels in gingival crevicular fluid (GCF). Bone physiology involves modeling and remodeling, with orthodontics applying forces to teeth, influencing tissue reactivity and bone modeling. ALP, a marker of osteoblast function, plays a crucial role in bone growth. GCF reflects immunological and inflammatory responses during orthodontic force application, making it a valuable medium for studying ongoing metabolic processes related to bone turnover. Aim The study aims to comparatively analyze ALP levels in GCF during growth modulation therapy, assessing the efficacy of Twin Block, Forsus Fatigue Resistant, and Clear Block appliances. The research involves 30 experimental samples divided into three study groups and a control group. The samples are collected at various time intervals, and ALP levels are analyzed using a spectrophotometer. Statistical analysis includes paired and unpaired t-tests, one-way analysis of variance (ANOVA), and multiple comparisons. Results Results demonstrate a significant increase in ALP levels during the growth modulation therapy, indicating a positive correlation with bone remodeling. Twin Block appears to be the most effective appliance, exhibiting higher ALP activity compared to Clear Block and Forsus groups. Conclusion In conclusion, this study provides valuable insights into the biochemical responses during growth modulation therapy, emphasizing the potential of GCF analysis in understanding orthodontic treatment effects.

Efficacy of clear aligner therapy over conventional fixed appliances in controlling orthodontic movement: A systematic review

OBJECTIVE

The purpose of the current systematic review was to answer the clinical research question "Is Clear Aligner Therapy (CAT) effective in controlling the orthodontic movement?" by bringing together the most up-to-date information about the available evidence for CAT.

METHODOLOGY

On January 1, 2023, a search was conducted in PubMed, ERIC, Embase, and CINHAL for any research papers published in the previous 10 years that provided an overview of the PICO questions. Both the titles and abstracts of the selected studies were evaluated independently by two different authors, and if there was any disagreement between the two review authors, a third reviewer was brought in to settle it.

RESULTS

Among included studies, three were retrospective non-randomized and two studies were prospective randomized clinical trials. Various authors reported better outcome for fixed orthodontic appliances than for clear aligner treatment (CAT) in relation to mandibular incisor proclination. The mean objective grading system score was better for braces (17) than for CAT (12) with no clinically significant difference, while staging had a significant impact on treatment efficacy.

CONCLUSION

The results of this study suggest that clear aligners may be an effective alternative to traditional braces, but more research is needed to confirm these findings and determine the optimal size of future prospective studies evaluating this treatment.

A narrative review of the effects of vitamin D3 on orthodontic tooth movement: Focus on molecular and cellular mechanisms

Orthodontic tooth movement (OTM) is a critical process in dental alignment, driven by the application of calibrated orthodontic forces. This study delves into the intricate molecular and cellular mechanisms by which vitamin D3 influences OTM. Vitamin D3 is identified as a critical regulator in bone metabolism, enhancing osteoblast activity and bone formation while also modulating osteoclast quantity and RANKL expression, essential for the remodeling of the alveolar bone. The precise mechanisms through which vitamin D3 facilitates these processes are explored, highlighting its potential in accelerating bone remodeling and, consequently, tooth alignment. This comprehensive review underscores vitamin D3's anabolic impact on bone metabolism and its pivotal role in the synthesis and mineralization processes governed by osteoblasts. The findings illuminate vitamin D3's promise in augmenting orthodontic therapy, suggesting its utility in improving treatment efficiency and reducing duration. However, the need for further research into the optimal application of vitamin D3 in orthodontics is emphasized, particularly concerning dosage, timing, and delivery methods.

Static magnetic field-induced IL-6 secretion in periodontal ligament stem cells accelerates orthodontic tooth movement

Static magnetic field (SMF) promoting bone tissue remodeling is a potential non-invasive therapy technique to accelerate orthodontic tooth movement (OTM). The periodontal ligament stem cells (PDLSCs), which are mechanosensitive cells, are essential for force-induced bone remodeling and OTM. However, whether and how the PDLSCs influence the process of inflammatory bone remodeling under mechanical force stimuli in the presence of SMFs remains unclear. In this study, we found that local SMF stimulation significantly enhanced the OTM distance and induced osteoclastogenesis on the compression side of a rat model of OTM. Further experiments with macrophages cultured with supernatants from force-loaded PDLSCs exposed to an SMF showed enhanced osteoclast formation. RNA-seq analysis showed that interleukin-6 (IL-6) was elevated in force-loaded PDLSCs exposed to SMFs. IL-6 expression was also elevated on the pressure side of a rat OTM model with an SMF. The OTM distance induced by an SMF was significantly decreased after injection of the IL-6 inhibitor tocilizumab. These results imply that SMF promotes osteoclastogenesis by inducing force-loaded PDLSCs to secrete the inflammatory cytokine IL-6, which accelerates OTM. This will help to reveal the mechanism of SMF accelerates tooth movement and should be evaluated for application in periodontitis patients.

The Influence of Orthodontic Treatment on Periodontal Health between Challenge and Synergy: A Narrative Review

By correctly repositioning teeth, orthodontic therapy improves both the function and appearance of an occlusion. The relationship between teeth and the tissues that surround and support them significantly influences these alterations. With ever more adults seeking orthodontic care, orthodontists are increasingly seeing patients with periodontal issues. Concerns about the patient's appearance, such as uneven gingival margins or functional issues caused by inflammatory periodontal diseases, should be accounted for when designing orthodontic treatment plans. Furthermore, orthodontics may increase the chances of saving and recovering a degraded dentition in cases of severe periodontitis. Today, general dentists, dontists, and orthodontists play integrative roles that enable them to achieve the best possible results for their patients. This review will improve the results of interdisciplinary treatments and increase cooperation between dental specialists by drawing attention to the essential connection between orthodontics and periodontics in regular clinical practice.

Effectiveness of low frequency vibration on the rate of canine retraction: a randomized controlled clinical trial

To investigate the effectiveness of AcceleDent Aura vibrating device on the rate of canine retraction. Thirty-two patients requiring extraction of upper first premolars and canine retraction were randomly allocated with a 1:1 ratio into either no-appliance group or the AcceleDent Aura appliance group. Canine retraction was done applying 150gm of retraction force using NiTi coil springs on 16 × 22 stainless steel archwires. The duration of the study was 4 months. Models were collected and digitized directly after extraction of upper first premolars and at monthly intervals during canine retraction for recording the monthly as well as the total distance moved by the canine. Digitized models were superimposed on the initial model and data were statistically analyzed. Anchorage loss, rotation, tipping, torque and root condition were evaluated using cone beam computed tomography imaging. Pain was evaluated by visual analog scale. No patients were dropped-out during this study. There was no statistically significant difference between both groups regarding the total distance travelled by the canine (P = 0.436), as well as the rate of canine retraction per month (P = 0.17). Root condition was the same for the two groups. Regarding the pain level, there was no statistically significant difference between the two groups at day 0 (P = 0.721), after 24 h (P = 0.882), after 72 h (P = 0.378) and after 7 days (P = 0.964). AcceleDent Aura was not able to accelerate orthodontic tooth movement. Pain level couldn't be reduced by vibrational force with an AcceleDent device during orthodontic treatment. Root condition was not affected by the vibrational forces.

Evaluation of Dentist Perception of Platelet Rich Plasma (PRP) for Accelerated Tooth Movement - Cross Sectional Survey

The current survey was conducted to assess the knowledge, awareness and perception of platelet-rich plasma (PRP) on accelerated tooth movement among dentist present in the state of Tamil Nadu. Tamil Nadu dentists were the subjects of the cross-sectional questionnaire survey. 500 participants completed self-administered questionnaires about their knowledge, awareness, and perception of PRP's effect on accelerated tooth movement. The Statistical Package for the Social Sciences (SPSS) (V 22.0) was used to do the statistical analysis. It computed the frequency distribution.The result showed that 466 (93.2%) had prior knowledge of PRP, whereas 34 (6.4%) had no previous experience with it. A total of 156 (31.2%) dentists were aware that PRP procedures are used for teeth rotation and canine retraction.15.2% of participants stated that PRP facilitates accelerated tooth movement.Therefore, results of the study show that the dentists were a little aware of PRP as an additional therapeutic strategy for accelerating tooth movement.More awareness required among the dentist regarding application and its benefits of PRP in accelerated tooth movement.

Effect of the antirheumatic medication methotrexate (MTX) on biomechanical compressed human periodontal ligament fibroblasts (hPDLFs)

BACKGROUND

The aim of this study was to investigate the in vitro effect of the antirheumatic drug methotrexate (MTX) on biomechanically compressed human periodontal ligament fibroblasts (hPDLFs), focusing on the expression of interleukin 6 (IL-6), as its upregulation is relevant to orthodontic tooth movement.

METHODS

Human PDLFs were subjected to pressure and simultaneously treated with MTX. Cell proliferation, viability and morphology were studied, as was the gene and protein expression of IL-6.

RESULTS

Compared with that in untreated fibroblasts, IL-6 mRNA expression in mechanically compressed ligament fibroblasts was increased (two to sixfold; ****p < 0.0001). Under compression, hPDLFs exhibited a significantly more expanded shape with an increase of cell extensions. MTX with and without pressure did not affect IL-6 mRNA expression or the morphology of hPDLFs.

CONCLUSION

MTX has no effect on IL-6 expression in compressed ligament fibroblasts.

The osteoclastic activity in apical distal region of molar mesial roots affects orthodontic tooth movement and root resorption in rats

The utilization of optimal orthodontic force is crucial to prevent undesirable side effects and ensure efficient tooth movement during orthodontic treatment. However, the sensitivity of existing detection techniques is not sufficient, and the criteria for evaluating optimal force have not been yet established. Here, by employing 3D finite element analysis methodology, we found that the apical distal region (A-D region) of mesial roots is particularly sensitive to orthodontic force in rats. Tartrate-resistant acidic phosphatase (TRAP)-positive osteoclasts began accumulating in the A-D region under the force of 40 grams (g), leading to alveolar bone resorption and tooth movement. When the force reached 80 g, TRAP-positive osteoclasts started appearing on the root surface in the A-D region. Additionally, micro-computed tomography revealed a significant root resorption at 80 g. Notably, the A-D region was identified as a major contributor to whole root resorption. It was determined that 40 g is the minimum effective force for tooth movement with minimal side effects according to the analysis of tooth movement, inclination, and hyalinization. These findings suggest that the A-D region with its changes on the root surface is an important consideration and sensitive indicator when evaluating orthodontic forces for a rat model. Collectively, our investigations into this region would aid in offering valuable implications for preventing and minimizing root resorption during patients' orthodontic treatment.

Comparison of the Effects of Ketorolac and Acetaminophen on RANK-L Levels in the Gingival Crevicular Fluid during Orthodontic Tooth Movement: A Pilot Study

Background: Patients usually present pain due to the release of different inflammatory mediators such as prostaglandin E2 and RANK-L. Analgesics such as acetaminophen and ketorolac can inhibit RANK-L expression and this can affect orthodontic treatment by decreasing bone remodeling and slowing orthodontic dental movement. Several studies have reported a decrease in dental movement after administering some non-steroidal anti-inflammatory drugs. Proposal: The objective was to evaluate the RANK-L levels and a possible modulation by administering acetaminophen and ketorolac in patients starting orthodontic treatment. Methodology: A double-blind, randomized clinical trial was carried out with 24 subjects divided into three study groups: calcined magnesia as a placebo, acetaminophen, and ketorolac. Gingival crevicular fluid was obtained at four time points: before pharmacological intervention, at 24 h, at 48 h, and on the 5th day. RANK-L concentrations were evaluated through ELISA analysis. Also, interproximal space generated by the elastic separator at the end of the study was recorded in the different study groups using the visual analog scale. Results: An increase in RANK-L at 24 h was observed in the placebo group compared to the ketorolac and acetaminophen groups. However, no significant differences were observed in the interproximal space at day 5 in the three study groups. Conclusion: Patients who do not take analgesics at the start of orthodontic treatment have higher levels of RANK-L. Therefore, the use of ketorolac or acetaminophen could decrease bone remodeling and interfere with orthodontic dental movement.