1 Volume 24 2025 e251512 Systematic Review and Meta-Analysis Braz J Oral Sci. 2025;24:e251512http://dx.doi.org/10.20396/bjos.v24i00.8671512 1 Orthodontist, Private Clinic, Rasht, Iran. 2 Orthodontist, Private Clinic, Isfahan, Iran. 3 Department of Orthodontics, College of Stomatology, The First Affiliated Stomatological Hospital, Xi’an Jiaotong University, Xi’an, PR China. 4 Department of Prosthodontics, Faculty of Dentistry, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Corresponding author: Ali Amiri Department of Orthodontics, College of Stomatology, The First Affiliated Stomatological Hospital, Xi’an Jiaotong University, Xi’an, PR China Tell: +86-2982655450 E-mail: draliamiri2020@gmail.com Editor: Dr. Altair A. Del Bel Cury Received: November 22, 2022 Accepted: October 10, 2024 Evaluation of the effect of using micro-implant in vertical control in angle class ii malocclusion patients: a systematic review and meta-analysis Sareh Keshavarz Meshkinfam1 , Fatemeh Teimoori2 , Ali Amiri3* , Fereshte Keikha4 Background and Aim: It is acknowledged that controlling the vertical dimension is a crucial and frequently challenging aspect of orthodontic treatment. The present study evaluated the micro-implant effect in angle class II malocclusion patients. Methods: All articles published in international databases such as PubMed, Scopus, Science Direct, ISI Web of Knowledge, and Embase between 2012 and July 2022 are included. Meta-analysis data collected from selected studies were performed using Stata/MP.V17 software. Results: The abstracts of 718 studies were reviewed, and finally, 12 studies were selected. The mean differences of vertical change of lower and upper molar between micro-implants were -0.88 (MD, 95% CI -1.15, -0.60; p=0.00). Conclusion: Based on the present study’s findings, using a Micro-implant compared to conventional anchorage has better vertical control. It is suggested that future studies be conducted with a similar cognitive methodology of higher quality and get help from methodological guidelines. Keywords: Malocclusion, Angle Class II. Dental arch. Orthodontic anchorage procedures. https://orcid.org/0000-0002-2356-594X https://orcid.org/0000-0003-0240-698X https://orcid.org/0000-0001-9416-808X https://orcid.org/0000-0003-3706-9389 2 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 Introduction Class II malocclusion is one of the most common problems in orthodontic treatment, char- acterized by protrusion of the upper jaw and retrognathia of the mandible1. Its frequency in children is reported to be 37%2. In people of non-growing ages, teeth displacement is generally used to compensate for jaw disharmony3. One of the most critical concerns of orthodontic treatment is minimizing side effects and maximizing tooth movement4. A type of maximum anchorage that is widely used is micro-implant (MI)5. Many advan- tages have been reported for MI, including minimal anatomic constraints, relatively low cost, ability to load forces immediately, ease of insertion and removal, and rapid recovery. However, the use of MI may be associated with the risk of damage to the roots of the teeth during implantation, especially when placed between teeth6. Vertical control is important in treating hyper-divergent malocclusion characterized by a high mandibular plane angle and a long face. According to multiple studies, vertical control is crucial for treating skeletal class II malocclusion with orthodontics. Using the ver- tical growth potential of adolescent patients to direct their facial development in the desired direction is frequently the most successful course of action6. Long face syndrome is formed by excessive vertical growth of the face with a back- wardly rotated mandible, an increased lower face height, and a tendency for open bite in severe cases. Studies have shown that MI is more effective in sagittal control than conventional anchorage (CA)7-9. There are many debates regarding the effectiveness of MI in vertical control, and this issue is very challenging. Studies have shown that MI can help mandibular clockwise rotation and have provided favorable results10,11. Moreover, some studies comparing MI with CA have found more molar extrusion12,13. There- fore, the study evaluated micro-implant effects in angle Class II malocclusion patients. Materials and Methods Search strategy Based on PRISMA guidelines14, the present study conducts a systematic review and meta-analysis of all articles published between January 2012 and July 2022 in inter- national databases, including PubMed, Scopus, Science Direct, Embase, and ISI Web of Knowledge. The Google Scholar search engine employed the PICO strategy to answer the research questions (Table 1). Table 1. PICO strategy. PICO strategy Description P Population: Class II malocclusion patients I Intervention: Micro-implant C Comparison: Conventional anchorage O Outcome: vertical change of upper and lower molar, change of occlusal plane, and chin position. 3 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 The following keywords were used to search: ((((“Orthodontic Anchorage Procedures”[Mesh]) AND “Malocclusion, Angle Class II”[Mesh]) OR “Malocclusion, Angle Class II/therapy”[Mesh]) AND “Dental Arch”[Mesh]) OR “Extraoral Traction Appliances”[Mesh] OR “ Micro-implant “[Mesh]. Eligibility criteria Inclusion criteria 1. Randomized controlled trials, controlled clinical trials. 2. The article’s full text was accessible. 3. No language restrictions. 4. Comparison of the intervention group with the control group. 5. Compared micro-implant with other types of anchorage. 6. Human samples. Exclusion criteria 1. Cohort, cross-sectional, retrospective, in-vitro, and in-vivo studies, review, case re- ports, letters to the editor, and animal studies. 2. Sample size less than 10. Selection process and Data collection process Two reviewers blindly and independently extracted data from the included papers’ full texts and abstracts for data extraction, and then data checklists were checked by a third independent and blind author. Duplicate items were removed, and each approved the final checklist of the three income authors. Kappa statistics were used to check the amount of agreement between the reviewers. The values of kappa were higher than 0.80. Studies data were reported by the first author’s name, years, study design, number of patients, intervention and control group, and outcome. Risk of bias assessment The quality of the randomized control trial studies was assessed using the Cochrane Col- laboration tool15. Low risk received a scale score of 1, while high and unclear risk received a score of 0. The scale scores range from 0 to 6. High quality means a higher score. The quality of the controlled clinical trial studies was assessed using the MINORS scale16. Data analysis Effect Measures and Synthesis Methods Stata/MP. v17 software was used to analyze the data. Mean differences (95% confi- dence interval) were used with a fixed effect model and inverse-variance method to examine the outcome. The level of heterogeneity was assessed using the I2 index test (I2 50% = low levels, 50-I2 75% = moderate, and I2>75% = high levels). 4 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 Results After the initial search for them in databases, 718 articles were identified. Duplicate articles were deleted (n=60) after importing all articles into the EndNote. X9 soft- ware. Six hundred fifty-eight articles were entered and examined in the second stage (abstract). At this stage, 554 unrelated articles were excluded from the study while reviewing the titles and abstract articles. The full texts of 104 articles were reviewed in the third step. Twelve articles that met the inclusion criteria and were published between January 2012 and July 2022 eventually entered the analysis. (Figure 1). Id en tif ic at io n Sc re en in g El ig ib ili ty In cl ud ed Literature search (n=718) Duplicate studies (n = 60) Review the abstract (n = 658) Excluded articles (n=554) Check the full text of the articles (n=104) Articles included (n=12) Excluded articles (n=92) Identification of studies via databases and registers Figure 1. PRISMA flowcharts. Characteristics The total number of patients in the Micro-implant and control groups were 105 and 91, respectively. Data extracted from the studies are summarized in Table 2. Risk assessment According to the Cochrane Collaboration tool, four randomized clinical trial studies were of high quality (low risk of bias), two had a moderately low risk of bias, and one was of low quality (Table 3). Total MINORS scores of 15-22 showed moderate quality; in the present study, all studies assessed with MINORS scores had moderate quality (Table 4). 5 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 Ta bl e 2. D at a ex tra ct ed fr om s el ec te d st ud ie s. N o. St ud y. Y ea rs O ut co m e N um be r o f p at ie nt s Si te a nd T yp e M ic ro -im pl an t Ra ng e of ag e In tr us io n of M ol ar s O cc lu sa l P la ne Ch an ge M ic ro -im pl an t gr ou p Co nt ro l gr ou p M ic ro -im pl an t gr ou p Co nt ro l g ro up Di am et er (m m ) Le ng th (m m ) M al e Fe m al e M al e Fe m al e 1 Di ng e t a l.17 , 20 19 De nt al , S ke le ta l 10 10 TP A+ M I H ea dg ea r 2. 0 10 15 -2 6 m an di bu la r pl an e −0 .3 1 ± 1. 26 2 Ta n an d W en li18 , 20 18 De nt al , S ke le ta l 20 20 U5 , U 6 J ho ok 1. 6 9 19 -2 6 m an di bu la r pl an e 0. 51 ± 0 .6 4 3 M en g et a l.19 , 20 17 De nt al , S ke le ta l 5 10 7 8 U5 , U 6 L5 /L 6 tp a 1. 6 11 18 -3 7 m an di bu la r pl an e 0. 8 ± 0. 3 4 M a et a l.20 , 2 01 6 Sk el et al , P ro fil e 15 15 U5 , U 6 TP A 1. 6 11 N R m an di bu la r pl an e 0. 35 ± 0 .9 4 5 W u et a l.21 , 2 01 5 De nt al , S ke le ta l 7 10 5 9 U5 , U 6 J ho ok 1. 6 11 18 -3 9 m an di bu la r pl an e 0. 18 ± 0 .2 7 6 Li an g et a l.22 , 20 14 Sk el et al 5 5 5 5 U5 , U 6 TP A 1. 5 10 18 -2 9 m an di bu la r pl an e −0 .7 7 ± 2. 3 7 Si e t a l.23 , 2 01 4 De nt al , S ke le ta l, Pr ofi le 0 16 0 16 U5 , U 6 J ho ok 1. 6 11 16 -3 0 m an di bu la r pl an e 0. 8 ± 3. 81 8 Ch en e t a l.24 , 20 15 De nt al , S ke le ta l, Pr ofi le 6 9 7 9 U5 , U 6 H ea dg ea r 1. 6 9 22 -3 0 m an di bu la r pl an e −0 .2 7 ± 0. 59 9 O uy an g an d Du 25 , 20 13 De nt al , S ke le ta l 0 10 0 10 U5 , U 6 H ea dg ea r 1. 6 9 18 -3 5 m an di bu la r pl an e −1 .5 1 ±  2. 6 10 Al -s ib ai e an d H aj ee r12 , 2 01 4 De nt al , S ke le ta l 9 19 12 16 U5 -U 6 TP A 1. 6 7 16 -2 9 m an di bu la r pl an e −0 .4 1 ± 1. 4 11 Li ao e t a l.26 , 2 01 2 De nt al , S ke le ta l, Pr ofi le 7 7 4 10 U5 -U 6 H ea dg ea r 1. 4 8 18 -3 7 m an di bu la r pl an e −1 .2 ± 2 12 Yu e t a l.27 , 2 01 2 De nt al , S ke le ta l 15 19 5 8 U1 -U 2, U 5- U 6 J ho ok 1. 6 11 22 -3 9 m an di bu la r pl an e −0 .4 1 ± 0. 48 U5 : u pp er s ec on d pr em ol ar ; U 6: u pp er fi rs t m ol ar ; U 1: u pp er in ci so r; U2 : u pp er la te ra l i nc is or ; L 5: lo w er s ec on d m ol ar ; L 6: lo w er fi rs t m ol ar . 6 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 Table 3. Risk of bias assessment (Cochrane Collaboration’s tool). Study Ra nd om s eq ue nc e ge ne ra tio n A llo ca tio n co nc ea lm en t Bl in di ng o f p ar tic ip an ts an d pe rs on ne l Bl in di ng o f o ut co m e as se ss m en t In co m pl et e ou tc om e da ta Se le ct iv e re po rt in g To ta l s co re Ding et al.17, 2019 + + ? + + + 5 Meng et al.19, 2017 + + ? + + + 5 Ma et al.20, 2016 + + ? + + + 5 Liang et al.22, 2014 + ? ? + + + 5 Si et al.23, 2014 ? ? ? ? + + 2 Al-sibaie and Hajeer12, 2014 ? ? + ? + + 3 Liao et al.26, 2012 ? ? + + + + 4 Table 4. MINORS score Study Cl ea rly s ta te d ai m In cl us io n of c on se cu tiv e pa tie nt s Pr os pe ct iv e da ta c ol le ct io n En dp oi nt s ap pr op ria te to st ud y ai m Un bi as ed a ss es sm en t o f st ud y en dp oi nt Th e fo llo w -u p pe rio d ap pr op ria te to th e st ud y’s a im <5 % lo st to fo llo w -u p Pr os pe ct iv e ca lc ul at io n of st ud y si ze A de qu at e co nt ro l g ro up Co nt em po ra ry g ro up s Ba se lin e eq ui va le nc e of gr ou ps A de qu at e st at is tic al a na ly se s To ta l Tan and Wenli18, 2018 2 2 2 2 2 0 0 0 2 2 0 2 16/24 Wu et al.21, 2015 2 2 2 2 2 0 0 0 2 2 0 2 16/24 Chen et al.24, 2015 2 2 2 2 2 0 0 0 2 2 2 2 18/24 Ouyang and Du25, 2013 2 2 2 2 2 0 0 0 2 2 0 2 16/24 Yu et al.27, 2012 2 2 2 2 1 0 0 0 2 2 0 2 15/24 7 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 Vertical change of upper and lower molar The mean difference of vertical change of lower molar between MI and CA was -0.88 (MD, 95% CI -1.15, -0.60; p=0.00) (I2=57.73%; P=0.12; moderate heterogeneity). A significant Vertical change was observed between the two groups, showing lower molar intrusion in the Micro-implant group (Figure 2). The mean difference of vertical change of upper molar between MI and CA was -0.53 (MD, 95% CI -0.62, -0.44; p=0.00) (I2=98.13%; P=0.00; high heterogeneity). A significant vertical change was observed between the two groups, showing that the micro-implant group performed significantly better in the upper molar intrusion (Figure 3). Figure 2. The forest plot showed a vertical change of lower molar between Micro-implant and conventional anchorage. Figure 3. The forest plot showed a vertical change of upper molar between Micro-implant and conventional anchorage. 8 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 Occlusal plane The mean difference of change of occlusal plane between MI and CA was -1.39 (MD, 95% CI -1.82, -0.96; p=0.00) (I2=93.49%; P=0.00; high heterogeneity). The difference in the change of occlusal plane between the two groups resulted in a decrease in the occlusal plane in the micro-implant group (Figure 4). Figure 4. Change of occlusal plane between Micro-implant and conventional anchorage. Chin position The mean change of chin position change between MI and CA was 0.16 (MD, 95% CI 0.12, 0.20; p=0.00) (I2=99.24%; P=0.00; high heterogeneity). According to the differ- ence in change of chin position between the two groups, the forward moving of the chin in the Micro-implant group was observed (Figure 5). Figure 5. Change of chin position between Micro-implant and conventional anchorage. Discussion The present study was conducted to investigate the effectiveness of MI in vertical control of orthodontic treatment. The current meta-analysis observed that MI reduced 9 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 the mandibular plane angle and intruding upper molars better than CA. It should be noted that vertical control during orthodontic treatment is important both theoret- ically and clinically. If correct vertical control is performed in patients with class II malocclusion, it leads to clockwise rotation of the mandible, which affects treatment. For the best orthodontic care, well-vertical control is crucial and may help lessen the jaws’ anteroposterior discrepancy. On the other hand, for every 1 mm that the molars were extruded, there was an approx- imate 3° increase in the mandibular plane angle. For class II patients, molar intrusion or preventing molar extrusion is necessary for successful treatment; however, from an aesthetic perspective, class III patients may not be appropriate candidates for MI treatment. Based on the study of molars and whole teeth, it penetrates with receding anterior teeth10,11. Some studies have shown that using MI from the beginning of treatment effectively improves treatment in patients with class II malocclusion11. In addition, the force used during retraction was focused on the MI rather than the molars, reducing friction and consistent with the original favoring thin wire and light force. As a result, the movement of teeth is close to the physiological movement21. The present study showed that MI performed significantly better in the upper molar intrusion. Peng et al.28, 2023 reported findings similar to the present study and showed that MI significantly decreased mandibular plane angle and intruded upper molars. According to the present meta-analysis, MI reduced the occlusal surface occlusal plane and changed the chin position observed in the MI group. Based on the findings of the present meta-analysis, MI can reduce the occlusal plate and improve the profile. Studies have reported that MI and CA improve the profile28. Studies have shown that class II elastic traction can negate vertical control and lead to the extrusion of lower molars20,21,27. Such studies have shown that vertical con- trol reduces anteroposterior jaw discrepancy, which is particularly important during orthodontic treatment25,29. The present meta-analyses showed the forward move- ment of the chin in the Micro-implant group. In the orthodontic treatment of class II patients, molar intrusion is essential for the success of the treatment. In class II patients, MI is not recommended due to aesthetics. Clinically, the anticorruption effect of anchorage in MI has been reported to be appropriate in treating class II malocclusions. However, evidence from RCTs needs to be more consistent. More clinical trial studies are needed to confirm the evidence6. When using MI on the bed, it is better to choose the location individually, and the infrazygomatic crown is suit- able. It is essential to assess adjacent anatomic structures and bone density before MI placement to assess the success of MI. In conclusion, based on the present study’s findings, micro-implant use has better vertical control than conventional anchorage. Most of the studies selected in the present study were of moderate quality, and heterogeneity between studies was high, so the results should be interpreted carefully. It is suggested that future studies be conducted with a similar cognitive methodology of higher quality and get help from methodological guidelines. 10 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 Conflict of interest The authors have no conflict of interest to disclose. Data availability Datasets related to this article will be available upon request to the corresponding author. Author Contribution Sareh Keshavarz Meshkinfam: Methodology, Writing - Original Draft and Writing - Review and Editing. Fatemeh Teimoori: Methodology, Writing - Original Draft and Writ- ing - Review and Editing. Ali Amiri: Conceptualization, Methodology, Formal Analysis, Investigation, Writing - Original Draft, Writing - Review and Editing and Visualization. Fereshte Keikha: Validation and Writing - Review and Editing. We declare that all authors actively participated in two distinct criteria related to authorship. All authors have revised and approved the final version of the manuscript. References 1. Batista KB, Thiruvenkatachari B, Harrison JE, O’Brien KD. Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children and adolescents. Cochrane Database Syst Rev. 2018 Mar;3(3):CD003452. doi: 10.1002/14651858.CD003452.pub4. 2. Li Y, Wu J, Guo J, Yu L, Wang J, Li X, et al. The efficacy of different treatment approaches for pediatric OSAHS patients with mandibular retrognathia: study protocol for a multicenter randomized controlled trial. Trials. 2020 Jun;21(1):595. doi: 10.1186/s13063-020-04398-9. 3. Volodymyr A, Sergii K, Kozyk O. Evaluation of the effectiveness of mini-screw-facilitated micro-osteoperforation interventions on the treatment process in patients with orthodontic treatment: a systematic review and meta-analysis. Int J Sci Res Dent Med Sci. 2021;3(3):147-52. doi: 10.30485/ijsrdms.2021.306970.1196. 4. Sotelo Núñez N, Hatamzade Z, Zamiri SS, Safi M. Evaluation the effect of micro-osteoperforation on the tooth movement rate and the level of pain on miniscrew-supported maxillary molar distalization: a systematic review and meta-analysis. Int J Sci Res Dent Med Sci. 2020;2(3):81-6. doi: 10.30485/ijsrdms.2020.240891.1077. 5. Liu Y, Yang ZJ, Zhou J, Xiong P, Wang Q, Yang Y, et al. Comparison of anchorage efficiency of orthodontic mini-implant and conventional anchorage reinforcement in patients requiring maximum orthodontic anchorage: a systematic review and meta-analysis. J Evid Based Dent Pract. 2020 Jun;20(2):101401. doi: 10.1016/j.jebdp.2020.101401. 6. Wang K, Fan H, Yang H, Li J, Xie W. Efficacy and safety of micro-implant anchorage in Angle class II malocclusion orthodontic treatment: A protocol for systematic review and meta-analysis. Medicine (Baltimore). 2020 Dec;99(50):e23221. doi: 10.1097/MD.0000000000023221. 7. Antoszewska-Smith J, Sarul M, Łyczek J, Konopka T, Kawala B. Effectiveness of orthodontic miniscrew implants in anchorage reinforcement during en-masse retraction: a systematic review and meta-analysis. Am J Orthod Dentofacial Orthop. 2017 Mar;151(3):440-55. doi: 10.1016/j.ajodo.2016.08.029. 11 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 8. Tian H, Xie C, Lin M, Yang H, Ren A. Effectiveness of orthodontic temporary anchorage devices in canine retraction and anchorage preservation during the two-step technique: a systematic review and meta-analysis. BMC Oral Health. 2020 Oct;20(1):278. doi: 10.1186/s12903-020-01271-8. 9. Li GF, Yang ZJ, Wang TC, Zhang CX, Zhang JY, Chen JD, et al. Meta-analysis dataset comparing orthodontic mini-implants and conventional anchorage reinforcement for maximum orthodontic anchorage. Data Brief. 2020 Jul;32:106010. doi: 10.1016/j.dib.2020.106010. 10. Liu YH, Ding WH, Liu J, Li Q. Comparison of the differences in cephalometric parameters after active orthodontic treatment applying mini-screw implants or transpalatal arches in adult patients with bialveolar dental protrusion. J Oral Rehabil. 2009 Sep;36(9):687-95. doi: 10.1111/j.1365-2842.2009.01976.x. 11. Deguchi T, Kurosaka H, Oikawa H, Kuroda S, Takahashi I, Yamashiro T, et al. Comparison of orthodontic treatment outcomes in adults with skeletal open bite between conventional edgewise treatment and implant-anchored orthodontics. Am J Orthod Dentofacial Orthop. 2011 Apr;139(4 Suppl):S60-8. doi: 10.1016/j.ajodo.2009.04.029. 12. Al-Sibaie S, Hajeer MY. Assessment of changes following en-masse retraction with mini-implants anchorage compared to two-step retraction with conventional anchorage in patients with class II division 1 malocclusion: a randomized controlled trial. Eur J Orthod. 2014 Jun;36(3):275-83. doi: 10.1093/ejo/cjt046. Epub 2013 Jun 20. 13. Kuroda S, Yamada K, Deguchi T, Kyung HM, Takano-Yamamoto T. Class II malocclusion treated with miniscrew anchorage: comparison with traditional orthodontic mechanics outcomes. Am J Orthod Dentofacial Orthop. 2009 Mar;135(3):302-9. doi: 10.1016/j.ajodo.2007.03.038. 14. Sohrabi C, Franchi T, Mathew G, Kerwan A, Nicola M, Griffin M, et al. PRISMA 2020 statement: What’s new and the importance of reporting guidelines. Int J Surg. 2021 Apr;88:105918. doi: 10.1016/j.ijsu.2021.105918. 15. Higgins JP, Altman DG, Gøtzsche PC, Jüni P, Moher D, Oxman AD, et al. The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials. BMJ. 2011 Oct;343:d5928. doi: 10.1136/bmj.d5928. 16. Kim SY, Park JE, Lee YJ, Seo HJ, Sheen SS, Hahn S, et al. Testing a tool for assessing the risk of bias for nonrandomized studies showed moderate reliability and promising validity. J Clin Epidemiol. 2013 Apr;66(4):408-14. doi: 10.1016/j.jclinepi.2012.09.016. 17. Ding SH, Liu MH, Zou TQ. Comparative study on vertical effect between miniscrew and face-bow in orthodontic treatment of hyperdivergent classⅡ protrusion. J Oral Sci Res. 2019;35(4):351-4. doi: 10.13701/j.cnki.kqyxyj.2019.04.011. 18. Tan Y, Wenli L. Comparison of the treatment outcomes between self-ligating brackets with microimplant and J hook anchorages in patients with Class II1 malocclusion. J Pract Stomatol. 2018;34:782-5. doi: 10.3969/j.issn.1001-3733.2018.06.013. 19. Meng QJ, Wang LC, Du X. Comparative study on the effect of miniscrew implants and transpalatal arch anchorage in the control of bi-maxillary dentoalveolar in adults. Chin J Pract Stomatol. 2017;10(2):88-91. 20. Ma N, Li WR, Chen XH, Zheng X. [Comparison of treatment results between implant anchorage and traditional intraoral anchorage in patients with maxillary protrusion]. Shanghai Kou Qiang Yi Xue. 2016 Aug;25(4):475-80. Chinese. 21. Wu X, Liu GY, Jiang YL. [Comparing the anchorage effects of micro-implant and J hook on treating patients with maxillary protrusion]. Shanghai Kou Qiang Yi Xue. 2015 Oct;24(5):623-6. Chinese. 22. Liang Y, Qian H, Sun WH. Effect of micro-implant anchorage in the treatment of Angle Class II division 1 malocclusion. Chin J Aesthet Med. 2014(24):2089-93. 12 Meshkinfam et al. Braz J Oral Sci. 2025;24:e251512 23. Si XQ, Zhang L, Zhang CD, Lu Z, Guo YC. [Comparison of the efficacy of implant-supported and J-hook-supported orthodontic treatment of ankylosing Class II, Division 1 malocclusion in young women]. Shaanxi Medi J. 2014;10:1345-7. Chinese. doi: 10.3969/j.issn.1000-7377.2014.10.036. 24. Chen M, Li ZM, Liu X, Cai B, Wang DW, Feng ZC. Differences of treatment outcomes between self- ligating brackets with microimplant and headgear anchorages in adults with bimaxillary protrusion. Am J Orthod Dentofacial Orthop. 2015 Apr;147(4):465-71. doi: 10.1016/j.ajodo.2014.11.029. 25. Ouyang ZF, Du X. Comparison of the treatment of Angle class II division 1 malocclusion in female adults with micro-implant anchorage and headgear anchorage technique. J Dent Prev Treat. 2013;21:203-7. 26. Liao SS, Liu ZT, Chen JL. Comparison of treatment effects between two anchorages in patients with skeletal class II malocclusion. Med J Commun. 2012;26:649-51. 27. Yu XH, Chen JC, Xun CL, Peng SY. Comparative analysis of the effects of micro-implant And J hook Treatmen for adult patients of angle class Ⅱ division 1 malocclusion with the anterior of the alveolar vertical macroplasia. Chin Mod Doc. 2012;50(7):42-4. doi: 10.3969/j.issn.1673-9701.2012.07.020. 28. Peng J, Lei Y, Liu Y, Zhang B, Chen J. Effectiveness of micro-implant in vertical control during orthodontic extraction treatment in class II adults and adolescents after pubertal growth peak: a systematic review and meta-analysis. Clin Oral Investig. 2023 May;27(5):2149-62. doi: 10.1007/s00784-023-04881-y. 29. Yao CC, Lai EH, Chang JZ, Chen I, Chen YJ. Comparison of treatment outcomes between skeletal anchorage and extraoral anchorage in adults with maxillary dentoalveolar protrusion. Am J Orthod Dentofacial Orthop. 2008 Nov;134(5):615-24. doi: 10.1016/j.ajodo.2006.12.022.