Journal of Orthodontic Science最新文献

This systematic review and meta-analysis evaluated the efficacy and safety of minimally invasive surgical techniques (MIS) to accelerate orthodontic tooth movement. A comprehensive search of PubMed, Web of Science, Cochrane CENTRAL, ProQuest, ScienceDirect, and OVID, along with manual reference screening, was conducted up to January 2024. Randomized controlled trials comparing MIS methods (including micro-osteoperforation, piezocision, flapless corticotomy/corticision, interseptal bone reduction, discision, and laser-assisted flapless corticotomy) with conventional orthodontic treatment were included. Thirty trials (809 participants) met eligibility criteria. Meta-analysis demonstrated significantly faster canine movement with MIS at one month (WMD 0.42 mm; 95% CI 0.26-0.58; P < 0.00001), two months (WMD 0.55 mm; 95% CI 0.35-0.75; P < 0.00001), and three months (WMD 0.52 mm; 95% CI 0.26-0.78; P = 0.0001). Subgroup analyses indicated micro-osteoperforation significantly accelerated movement (P < 0.05), while flapless corticotomy was not effective beyond two months (P > 0.05). Overall treatment time was reduced (WMD -42.30 days; 95% CI -68.31 to -16.30; P = 0.001), while no significant difference was found for en-masse retraction (WMD 1.55; 95% CI -0.65 to 3.76; P = 0.17). Reported adverse effects were minimal, with rare unintended tooth movements. MIS appears effective in accelerating orthodontic tooth movement and reducing treatment duration, particularly early in treatment, but heterogeneity highlights the need for standardized protocols and long-term multicenter trials.

Context: Mini-implant-assisted rapid palatal expansion (MARPE) has become an effective nonsurgical method for maxillary expansion in adults. The success of this method depends on the proper placement of mini-implants.

Aims: This study aimed to assess the thickness of the palatal bone (TPB), palatal bone density (PBD), and thickness of the palatal soft tissue (TPS) using cone-beam computed tomography (CBCT) and to explore their relationships with the palatal depth angle (PDA).

Settings and design: A retrospective cross-sectional study analyzed CBCT scans of 61 adults (31 males, 30 females; average age: 23.9 ± 7 years) conducted at the Faculty of Dentistry, Sana'a University.

Methods and materials: Measurements of TPB, PBD, and TPS were obtained at 14 sagittal levels starting 3 mm posterior to the incisive foramen and continuing at 2-mm intervals and bilaterally at 3 and 6 mm from the midpalatal suture, resulting in 56 measurement points per scan. PDA was measured as the angle formed by the anterior alveolar crest, the deepest palatal point, and the posterior nasal spine.

Statistical analysis used: Intra-examiner reliability was evaluated using the intraclass correlation coefficient. Data analysis was performed using the Statistical Package for the Social Sciences version 25.0 (IBM, Armonk, USA). A P-value <0.05 was considered statistically significant.

Results: TPB and PBD were the greatest in the anterior region and gradually decreased toward the posterior palate (P < 0.001). Males showed significantly higher TPB values (P < 0.01), and PBD differences between genders were minimal. TPS was generally higher at lateral points (P < 0.05). A significant positive correlation was observed between PDA and TPB, especially in the anterior (r = 0.324, P < 0.001) and middle regions (r = 0.476, P < 0.001).

Conclusion: Variations in TPB and PBD help identify the most favorable regions for mini-implant placement. The anterior and middle regions are suitable for implant placement and offering bicortical anchorage when TPB is inadequate in the middle. A higher PDA (indicating a flatter palate) correlated with greater TPB in these areas-and vice versa.

Background: Distalization in orthodontics is one of the conservative modalities for gaining space in orthodontics. The skeletally anchored distalizers avoid the adverse effects of the dentally anchored ones.

Objective: The current study aimed to evaluate the effects of the skeletally anchored modified Leaf Expander, (Leaf Expander^®, Leone SpA, Sesto Fiorentino, Florence, Italy) (MLE) as a distalizer versus the skeletally anchored modified Carriere Motion Appliance (CMA) (Henry Schein Orthodontics (HSO), Australia).

Patients and methods: Thirty orthodontic patients, aged 15 to 18, were involved in the present study. Group I comprised 15 patients who were treated with the skeletally anchored modified Leaf expander (MLE as a distalizer. Group ΙΙ involved 15 patients who were treated by the skeletally anchored modified Carriere Motion Appliance (CMA. Amount of molar distalization, molar tipping, Overjet, ANB (angle formed between A point, Nasion and B point), and vertical skeletal changes (FH-MP) (angle formed between the Frankfort plane and the mandibular plane), arch length, and transverse dimensions have been assessed by using digital models. All data were analyzed using SPSS version 20.0 (IBM Corp., USA). Normality was verified by the Shapiro-Wilk test.

Results: Upper first molar distalization (U6-VRL) (distance from mesiobuccal cusp of upper first molar to vertical reference line from S point; measures distal movement.) showed a highly significant difference (P < 0.001, d = 5.96 - very large), with the MLE achieving almost double the distal movement of CMA (-7.65 ± 0.74 mm for MLE Group, -3.03 ± 1.84 for CMA).

Conclusion: The skeletally anchored modified Leaf expander (MLE) as a distalizer produces a greater amount of maxillary molar distalization and less molar tipping than that produced by the skeletally anchored modified Carriere Motion Appliance (CMA).

This systematic review aims to assess the impact of rapid maxillary expansion (RME) on masticatory muscle activity through electromyographic analysis. A systematic review was conducted according to the Cochrane Collaboration guide. The PICO strategy was employed to formulate the clinical question. A comprehensive search review was performed up to September 2022 across five databases (PubMed, Web of Science, Scopus, Embase, and Cochrane) and gray literature (Google Scholar). The risk of bias was performed using the Risk of Bias in Nonrandomized Studies of Interventions (ROBINS I) tool. Means and standard deviations were extracted to perform the meta-analysis, and overall quality was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach. Nine nonrandomized studies with a moderate risk of bias were included in this systematic review. Meta-analysis of electromyographic data during clenching demonstrated an increase in anterior temporal muscle activity after RME (P < 0,05). By contrast, masseter muscle activity at rest decreased after RME. According to the GRADE approach, the overall quality of evidence of the studies ranged between very low and moderate. RME altered masseter and anterior temporal muscle activities. Understanding the impact of RME on masticatory muscle activity is essential in order to optimize treatment outcomes.

Objective: To compare pain experiences in patients treated with self-ligating (SmartClip™) and conventional (Victory™) preadjusted edgewise brackets during initial alignment.

Materials and methods: Seventy-three patients (50 females and 23 males) between 15 and 21 years of age were randomly allocated either the SmartClip appliance or the Victory^TM Series appliance. The participants rated their overall pain experience on a 100-mm visual analogue scale (VAS) at five time points: 6 hours (T1), 24 hours (T2), 3 days (T3), 1 week (T4), and 2 weeks after bracket placement (T5). All teeth were in the permanent dentition and had mild lower incisor crowding as assessed by Little's Irregularity Index. Moreover, participants reported any anti-inflammatory medication. An independent t-test was used to assess differences between both groups in terms of pain experience.

Results: Pain peaked between 24 hours and 3 days and gradually declined. No significant differences in pain scores were observed between groups at any time point (P > 0.05).

Conclusion: There were no clinically significant differences in pain perception between the two bracket systems during initial alignment. The current evidence does not support claims that one bracket system results in lower perceived pain levels than another.

Aim and objectives: This study aimed to evaluate and compare the biomechanical behavior of titanium and poly-ether-ether-ketone (PEEK) orthodontic mini-screws. The objectives were to assess their performance through four biomechanical tests: maximum insertion torque (MIT), fracture torque (FT), vertical pull-out strength (VPS), and horizontal resistance (HR).

Materials and methods: A total of 156 mini-screws (78 titanium, 78 PEEK), equally divided into 1.4 mm and 1.6 mm diameter groups, were inserted into artificial bone blocks under standardized in vitro conditions. Mechanical testing was conducted to evaluate each performance parameter. Data were analyzed using IBM statistical package for the social sciences (SPSS) software via one-way analysis of variance (ANOVA) or the Kruskal-Wallis test, depending on distribution, with a significance level of P < 0.05.

Results: The 1.6 mm PEEK group exhibited insertion torque comparable to titanium (P > 0.05), although overall PEEK screws showed lower MIT values. In FT, VPS, and HR tests, PEEK screws frequently deformed, or fractured under loading, whereas titanium screws demonstrated significantly higher mechanical performance (P < 0.001).

Conclusion: Titanium mini-screws outperformed unreinforced PEEK screws across all mechanical tests, demonstrating superior torsional, pull-out, and lateral resistance. Additionally, larger-diameter screws (1.6 mm) showed better mechanical performance than smaller ones (1.4 mm) in both materials.

Aims: Endothelin-1 (ET-1) increased bone resorption during orthodontic tooth movement (OTM) in animal models, suggesting potential clinical applications for accelerating OTM. However, the molecular mechanisms by which ET-1 regulates the expression of genes involved in OTM in human periodontal ligament (hPDL) cells remain unexplored. This study investigated the effect of ET-1 on vascular endothelial growth factor (VEGF) and cyclooxygenase-2 (COX-2) expression and PGE2 production in hPDL cells.

Materials and methods: hPDL cells were treated with 1, 10, and 100 pM ET-1 for 24 h, and cytotoxicity was assessed by MTT assay. The time-course and dose-response effects of ET-1 on VEGF expression were evaluated. For COX-2 expression, cells were treated with 10 pM ET-1 for 0.5, 1, 2, and 4 h. Quantitative polymerase chain reaction was used to measure VEGF and COX-2 mRNA levels, and enzyme-linked immunosorbent assay was performed to assess PGE2 production. To explore the role of the extracellular signal-regulated kinase (ERK) pathway, cells were pretreated with PD98059 before ET-1 exposure. Statistical significance was determined by one-way analysis of variance or Kruskal-Wallis test.

Results: ET-1 at 1-100 pM showed no cytotoxic effects. ET-1 did not significantly affect VEGF expression at any time point or dose tested. In contrast, ET-1 significantly increased COX-2 expression and PGE2 production at 1 h (P < 0.05). PD98059 did not inhibit ET-1-induced COX-2 expression, suggesting that ET-1 regulates COX-2 via an ERK-independent mechanism.

Conclusion: ET-1 upregulates COX-2 expression and PGE2 synthesis in hPDL cells through an ERK-independent pathway, while exerting no significant effect on VEGF expression. Further studies are warranted to assess the therapeutic potential of ET-1 in accelerating OTM.

Objectives: This study aimed to evaluate facial soft-tissue features in adults with skeletal Class I relationships using three-dimensional (3D) imaging and machine learning to identify sex-specific anthropometric patterns and provide reference data for orthodontic assessments.

Materials and methods: A total of 94 Saudi Arabian adults (50 men, mean age 25 ± 2.1 years; 44 women, mean age 23 ± 1.9 years) with Class I skeletal and dental relationships and body mass index (BMI) <25 kg/m² were included in this cross-sectional study. Standardized 3D facial photographs were obtained using a radiation-free system (ProMax 3D ProFace, Planmeca Oy, Helsinki, Finland). Sex differences were evaluated using conventional statistical tests. An L1-regularized logistic regression model was applied for feature selection and sex classification. Model performance was assessed using accuracy, precision, recall, F1-score, and area under the receiver operating characteristic curve (AUC).

Results: Significant sexual dimorphism was observed in facial regions. Men exhibited greater vertical and transverse dimensions, particularly in the mandible, middle face, and ocular region. Middle facial width was significantly greater in men than in women (135.82 ± 9.43 mm vs. 129.03 ± 7.13 mm; P < 0.001). Women showed higher vermilion height-to-mouth width and upper face height-to-mandibular width ratios. The machine learning model classified sex with high accuracy (91.3% ± 6.2%), precision (96.0% ± 8.0%), recall (85.5% ± 11.9%), F1-score (89.7% ± 7.0%), and AUC (0.91 ± 0.07).

Conclusions: This study demonstrates that combining 3D facial imaging with machine learning effectively captures sexual dimorphism in a Saudi Arabian adult population. The findings provide clinically relevant reference data for personalized orthodontic assessment and treatment planning and support forensic applications.

Background: Saliva is a valuable, noninvasive diagnostic fluid that mirrors the body's health, especially during physiological changes such as orthodontic tooth movement. The application of orthodontic force triggers an inflammatory response in the periodontal ligament, leading to the release of biomarkers like Vascular Endothelial Growth Factor (VEGF) and Transforming Growth Factor Beta 1 (TGF-β1), both crucial for bone remodeling and tissue repair. However, there are limited data on how salivary levels of these biomarkers change during different stages of fixed orthodontic treatment with NiTi archwires. The aim of the study was to determine the salivary levels of VEGF and TGF-β1 during each stage of the fixed orthodontic treatment using NiTi wires.

Materials and methods: This prospective observational study involved 11 patients requiring fixed orthodontic treatment with premolar extraction. Saliva samples were collected at four different time intervals: T0, Pretreatment; T1, 1 month after placement of 0.014/0.016 Round NiTi; T2, 1 month after placement of 0.017 × 0.025 Rectangular NiTi; and T3, 1 month after placement of 0.019 × 0.025 Rectangular NiTi. VEGF and TGF-β levels were analyzed using a high-sensitivity enzyme-linked immunosorbent assay (ELISA). The data were analyzed using repeated measures ANOVA.

Results: The mean VEGF concentration was 260.00 ± 188.42 pg/mL at T0, 144.32 ± 175.81 pg/Ml at T1, 228.95 ± 142.05 pg/Ml at T2, and 309.11 ± 285.43 pg/mL at T3. Although fluctuations in VEGF levels were observed over time, the difference was not statistically significant (F = 1.679, P = 0.215). The mean TGF-β1 concentration was 111.64 ± 58.99 pg/mL at T0, 99.29 ± 18.01 pg/mL at T1, 115.00 ± 87.90 pg/Ml at T2, and 92.93 ± 54.07 pg/mL at T3. Despite these variations across the time points, the difference was not statistically significant (F = 0.353, P = 0.659).

Conclusion: Though the VEGF and TGF-β1 levels in saliva showed significant clinical changes, they did not show statistically significant variation across the different stages of orthodontic treatment. However, the findings of this study indicate that saliva can be used as an alternative to gingival crevicular fluid (GCF) for estimating the levels of TGF-β1, which addresses a significant gap in the literature. Future research with larger sample sizes and more diverse populations is required to fully establish the reliability and generalizability of salivary VEGF and TGF-β1 monitoring in orthodontic practice.

Objectives: Mini-screw implants (MSI) are widely used in orthodontics as temporary anchorage device. Implant geometry, including shape and diameter, is a major contributor to their mechanical retention, and osseointegration. This study aimed to evaluate the influence of MSI shape (cylindrical vs. tapered), and diameter (1.2 vs. 1.4 mm) on peak removal torque (PRT) over different subsequent periods with 7 mm length for all used MSI.

Material and methods: A total of 160 titanium mini-screws were inserted into the tibiae of three adult sheep. Implants were divided into four groups according to shape and diameter, further subdivided by different post-insertion removal intervals: immediate, 2 weeks, 4 weeks, and 6 weeks. As eight implants per animal multiple by three animals result in 24 implants per group per time. A standardized surgical protocol was used, and PRT was measured using a digital torque driver. Statistical analysis was conducted using three-way ANOVA, where P ≤ 0.05.

Results: PRT values increased significantly across all groups over time. Larger diameter implants (1.4 mm) exhibited significantly higher torque values compared to 1.2 mm implants at all time points. Cylindrical MSI generally outperformed tapered implants at 4 and 6 weeks. The highest torque values were recorded at 6 weeks in all groups.

Conclusion: Implant diameter and shape significantly affect MSI stability. Larger diameters provide superior mechanical retention, while cylindrical shapes may offer advantages in later healing stages. These findings support selection of MSI geometry to optimize clinical outcomes in orthodontic anchorage.