 Masticatory performance, orthodontic treatment and quality of life Eur J Transl Myol 34 (1) 12101, 2024 doi: 10.4081/ejtm.2024.12101 - 1 - Masticatory performance and oral health related to quality of life before and after orthodontic treatment: a systematic review and meta-analysis Berahman Sabzevari (1), Arezousadat Fatemi (2), Milad Soleimani (3), Seyed Masoud Sajedi (4), Roksana Babazadehkhoushrodi (5) (1) Private practice, Mashhad, Iran; (2) Public dental clinic practice, Stavanger, Norway; (3) Department of Orthodontics, School of Dentistry, Alborz University of Medical Sciences, Karaj, Iran; (4) Department of Oral and Maxillofacial Medicine, Faculty of Dentistry, Shahed University, Tehran, Iran; (5) General Dentistry, Zahedan University of Medical Sciences, Zahedan, Iran. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License (CC BY-NC 4.0) which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. Abstract Masticatory performance is considered an important step in the beginning of the digestive process and considering the patient’s aesthetic and functional factors, it is necessary to choose appropriate treatments. Based on the evidence during orthodontic treatment, the restoration of the physiological function of masticatory performance should not be neglected. The present study aimed to evaluate the association between orthodontic treatment and improved masticatory performance and oral health related to quality of life. In the present study, all articles published till the end of August 2023 were extracted by two trained researchers independently through a search in databases like PubMed, Scopus, Science Direct, ISI, Web of Knowledge, Elsevier, Wiley, and Embase, and Google Scholar search engine using keywords and their combinations. Data analysis was done using the fixed effects model in a meta-analysis, by STATA (version 17); a P-value of less than 0.05 was considered significant. Based on the results, the mean difference in masticatory performance between pre-treatment and post-treatment was 2.23 (MD: 2.23; 95CI, 2.17, 2.29. p<0.01; I2= 99.98%; p<0.01). The mean difference in oral health related to quality of life between pre-treatment and post-treatment was -32.23 (MD: -32.23; 95CI, - 33.35, -31.11. p<0.01; I2= 97%; p<0.01). Orthodontic treatment had a positive effect on masticatory performance and improved the quality of life of patients after treatment. Key Words: orthodontic treatment; masticatory performance; oral health; quality of life. Eur J Transl Myol 34 (1) 12101, 2024 doi: 10.4081/ejtm.2024.12101 Restoring masticatory performance is an important goal of orthodontic treatment. In the past, the sieving method was used to measure chewing performance.1 Due to the complexity of this method, simpler methods are used today, one of which is measuring the amount of glucose while chewing gum jelly. Studies have shown a positive correlation between chewing performance and the new method, compared to the old method.2 Another important consequence of dental care, especially during orthodontic treatment, is Oral Health-Related Quality of Life (OHRQoL).3,4 Based on the results of the studies, patients experience difficulty in masticatory performance with the loss of teeth, and OHRQoL decreases. Orthodontic treatment can improve masticatory performance and increase OHRQoL to some extent.1 The use of dental prostheses also has a significant impact on masticatory performance and OHRQoL.5,6 Since chewing is considered an important step in the beginning of the digestive process, and considering the aesthetic and functional factors of the patients, it is necessary to choose appropriate treatments.7 Therefore, considering the importance of the subject, studies should reach a consensus to provide sufficient evidence in this field. The present systematic review and meta-analysis study aimed to evaluate masticatory performance and quality of life before and after orthodontic treatment. Materials and Methods Search strategy In the present study, articles related to treatment before, during, and after orthodontics, which investigated masticatory performance and OHRQoL, were examined. Masticatory performance, orthodontic treatment and quality of life Eur J Transl Myol 34 (1) 12101, 2024 doi: 10.4081/ejtm.2024.12101 - 2 - Articles published in international databases such as PubMed, Web of Science, Scopus, Science Direct, Web of Knowledge, EBSCO, Wiley, ISI, Elsevier, Embase, and Google Scholar search engine were accessed. The search process until August 2023 was done using MeSH keywords: "Index of Orthodontic Treatment Need"[Mesh]) OR "Index of Orthodontic Treatment Need/methods"[Mesh]) OR ( "Index of Orthodontic Treatment Need/classification"[Mesh] OR "Dental Occlusion"[Mesh]) AND "Masticatory Muscles"[Mesh]) OR "Mastication"[Mesh]) AND " Masticatory efficiency " AND "Chewing ability" AND " Chewing efficiency" AND "Oral Health"[Mesh]), AND "Quality of Life"[Mesh]. Study selection criteria Inclusion criteria Randomized controlled trials, prospective studies, observational studies, before–after studies, studies published in the English language, and orthodontics treatment. Case report articles, cohort studies, case- control studies, review articles, systematic review studies with incomplete results, animal studies, and editorial articles were excluded. Data collection After searching the articles, the details of each selected article, including the author's name, type of study, year of publication, characteristics of participants, age of participants, and sample size were collected by two researchers independently, with blinding. Data analysis Meta-analysis was performed using effect size with a 95% confidence interval (CI). To estimate the heterogeneity of the studies, the index I2 (<25%: weak heterogeneity, 25-75%: moderate heterogeneity, and more than 75%: high heterogeneity) was used. The results were combined using the fixed effect model (Inverse-variance method) in meta-analysis. Publication bias was checked through the Egger test and data analysis done through STATA/MP. v17 software. A p-value of less than 0.05 was considered significant. Results Through a search with the related keywords, 214 studies were identified. Endnote.X8 software was used to organize them. By using this software and reviewing the titles and abstracts of the articles, 81 duplicate studies were eliminated, while 11 articles were marked ineligible by automation tools. Then the researchers examined the abstracts of 122 articles. Ninety-four studies did not meet the inclusion criteria or were excluded due to weak or unrelated relevance to the study objective (if after reading the title and abstract, it was not possible to decide about the article, the full text was referred to). The full text of 28 articles was carefully reviewed by two independent researchers, and 19 studies were excluded due to the inconsistency with the study objectives; finally, nine articles were selected (Figure 1, Table 1). Fig 1. PRISMA 2020 Checklist. Records identified (n =214) Records removed before screening: Duplicate records (n = 81) Records marked as ineligible by automation tools (n = 11) Records screened (n=122) Records excluded (n = 94) Reports sought for retrieval (n =0) Reports not retrieved (n = 0) Full text (n =28) Reports excluded: (n = 19) Included studies (n =9) Identification of studies via databases and registers Id en tif ic at i Sc re en in g In cl ud ed Masticatory performance, orthodontic treatment and quality of life Eur J Transl Myol 34 (1) 12101, 2024 doi: 10.4081/ejtm.2024.12101 - 3 - The mean difference of masticatory performance between pre- and post-treatment was 2.23 (MD: 2.23; 95CI, 2.17,2.29. p<0.01; I2= 99.98%; p<0.01). Masticatory performance after orthodontic treatment was lower than pre-treatment; it significantly improved post- treatment (p<0.01) (Figure 2) The mean difference of OHRQoL between pre-and post- treatment was -32.23 (MD: -32.23; 95CI, -33.35, -31.11. p<0.01; I2= 97%; p<0.01). A decrease in OHRQoL after treatment showed that OHRQoL greatly improved after orthodontic treatment in the included studies (Figure 3). Table 1. Overview of included studies. Study. Years Study type Number of participants Sex Range or mean of age (years) Types of orthodontic treatments Malocclusion Assessment Male Female Ashok et al., 2023.8 Prospective study 20 9 11 12-16 Orthodontic treatment with functional jaw orthopedics Class II Masticatory performance Lee et al., 2023.9 Prospective study 52 26 26 18-48 Fixed orthodontic treatment Class I Masticatory performance Maurya et al., 2022.10] Randomized controlled trial 55 22 33 NR Fixed orthodontic treatment Class I, II, III Masticatory performance do Amaral et al., 2020.11 Sectional study 215 110 105 15-19 Fixed orthodontic treatment 57.7% Masticatory performance Ni et al., 2019.12 Longitudinal study 21 11 10 24.51±0.6 1 Surgical orthodontic treatment - OHRQoL Gameiro et al., 2017.1 prospective study 17 9 8 24.2 ± 6 Fixed orthodontic treatment NR Masticatory performance Alanko et al., 2017.17 prospective study 22 6 16 18-54 Fixed orthodontic treatment - OHRQoL Huang et al. 2016.14 prospective study 50 25 25 25.7±0.14 Surgical orthodontic treatment - OHRQoL Antoun et al., 2015.15 Prospective study 29 14 15 19.4±4.3 Fixed orthodontic treatment - OHRQoL Fig 2. Forest plot showed masticatory performance before and after orthodontic treatment. Masticatory performance, orthodontic treatment and quality of life Eur J Transl Myol 34 (1) 12101, 2024 doi: 10.4081/ejtm.2024.12101 - 4 - Discussion Surveys have reported that in younger age groups and the young generation, concern regarding aesthetics is very high. This generation pays more attention to the beauty of the teeth and their teeth.1,12 According to the findings, the inability to chew also makes people care about their teeth.8,9 Studies have shown that orthodontics can be effective by correcting malocclusion on symmetry in chewing movements and improving masticatory performance.1,10,11 Studies have also found that the quality of life increases after orthodontic treatment, with improvement in masticatory performance.12,13 Ashok et al. reported improved masticatory performance after orthodontic treatment in patients with class II malocclusion. This affected the beauty and performance of the patients, and consequently, the quality of life.14 Lee et al. found increased masticatory performance immediately after orthodontic treatment. In this study, tooth extraction did not affect the improvement of masticatory performance after orthodontic treatment.15 Another study observed that in all malocclusion groups, bite force improved after orthodontic treatment.16 By examining the quality of life in a study, research has reported that before orthodontics, there quality of life in patients with class III malocclusion was low, but improved significantly after the orthodontic treatment stage.17 Another study reported that orthodontic treatment supports psychological well-being, but the range of individual variation is wide.18 Huang et al. concluded that orthodontic treatment affects the quality of life significantly and effectively.19 The quality of life after orthodontic treatment improved compared to before treatment, with a significant difference observed therein between age and gender.20 Studies that have shown the positive effect of orthodontic treatments on the masticatory system have reported that orthodontic treatment regulates muscle activity by training muscles for symmetrical function.17 Orthodontic treatment facilitates and regulates muscle activity, as well as masticatory performance.21,22 Studies have reported the chewing performance of different malocclusions with mixed results. Patients were reportedly able to detect improvements in their chewing function during treatment.23,24 In conclusion, the findings of the present meta-analysis reveal that orthodontic treatment has a positive effect on masticatory performance and that orthodontic treatments can improve the patients’ quality of life after treatment. Therefore, patients should be provided with dietary instructions before starting the treatment to maintain the devices and avoid discomfort during the treatment. Considering the high heterogeneity observed between the studies, more studies should be conducted with the same cognitive method to study the aesthetic and physiological aspects. List of acronyms ANOVA - analysis of variance CI- confidence interval OHRQoL - Oral Health-Related Quality of Life Contributions of Authors BS: Conception and design, methodology, data collection, analysis and interpretation of data, drafting the article, final approval; RB: Conception and design, drafting the article, final approval; AF: Analysis and interpretation of data, drafting the article, final approval; MS: Revising it critically, analysis of data, final approval; SMS: Revising it critically, analysis of data, final approval; BS: Methodology, drafting the article, supervision, final approval; RB: Conception and design, method All authors read and approved the final edited typescript. Acknowledgments We would like to thank the authors of all selected studies for access to published data. Funding None. Fig 3. Forest plot showed OHRQoL before and after orthodontic treatment. Masticatory performance, orthodontic treatment and quality of life Eur J Transl Myol 34 (1) 12101, 2024 doi: 10.4081/ejtm.2024.12101 - 5 - Conflict of Interest The authors declare no competing interest. Ethical Publication Statement We confirm that we have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines. Corresponding Author Roksana Babazadehkhoushrodi, Zahedan University of Medical Sciences, Zahedan, Iran. ORCID iD: 0009-0005-1477-7077 E-mail: rbabazadehkhoushrodi@gmail.com E-mails and ORCID iD of co-authors Berahman Sabzevari: Bersabzevari@proton.me ORCID iD: 0000-0001-9713-4096 Arezousadat Fatemi: Fatemiarezoo@gmail.com ORCID iD: 0000-0003-4139-0810 Milad Soleimani: m.soleimani@abzums.ac.ir ORCID iD: 0000-0002-1847-254 Seyed Masoud Sajedi: s.sajedi@shahed.ac.ir ORCID iD: 0000-0002-8081-2062 References 1. Gameiro GH, Magalhães IB, Szymanski MM, Andrade AS. Is the main goal of mastication achieved after orthodontic treatment? A prospective longitudinal study. Dental Press J Orthod. 2017 May-Jun;22(3):72-78. doi: 10.1590/2177- 6709.22.3.072-078.oar. PMID: 28746490; PMCID: PMC5525448. 2. Yoshinori K, Hiroshi S, Ichiro A, Masaoki Y. The effectiveness of measuring glucose extraction for estimating masticatory performance. Prosthodontic Research & Practice. 2006;5(2):104–8. 10.2186/prp.5.104 3. Dimberg L, Lennartsson B, Bondemark L, Arnrup K. Oral health-related quality-of-life among children in Swedish dental care: The impact from malocclusions or orthodontic treatment need. Acta Odontol Scand. 2016;74(2):127-33. doi: 10.3109/00016357.2015.1059485. Epub 2015 Jul 24. PMID: 26206412. 4. Graziani F, Tsakos G. Patient-based outcomes and quality of life. Periodontol 2000. 2020 Jun;83(1):277-294. doi: 10.1111/prd.12305. PMID: 32385874. 5. Techapiroontong S, Limpuangthip N, Tumrasvin W, Sirotamarat J. The impact of poor dental status and removable dental prosthesis quality on body composition, masticatory performance and oral health-related quality of life: a cross-sectional study in older adults. BMC Oral Health. 2022 Apr 27;22(1):147. doi: 10.1186/s12903-022-02103-7. PMID: 35477491; PMCID: PMC9044772. 6. Yamamoto S, Shiga H. Masticatory performance and oral health-related quality of life before and after complete denture treatment. J Prosthodont Res. 2018 Jul;62(3):370-374. doi: 10.1016/j.jpor.2018.01.006. Epub 2018 Mar 13. PMID: 29548978. 7. Zanon G, Contardo L, Reda B. The Impact of Orthodontic Treatment on Masticatory Performance: A Literature Review. Cureus. 2022 Oct 19;14(10):e30453. doi: 10.7759/cureus.30453. PMID: 36415350; PMCID: PMC9674042. 8. do Amaral BA, Gondim Filgueira AC, da Silva- Neto JP, de Lima KC. Relationship between normative and self-perceived criteria for orthodontic treatment need and satisfaction with esthetics and mastication in adolescents. Am J Orthod Dentofacial Orthop. 2020 Jan;157(1):42- 48.e2. doi: 10.1016/j.ajodo.2019.01.025. PMID: 31901279. 9. Xiao-Ting L, Tang Y, Huang XL, Wan H, Chen YX. Factors influencing subjective orthodontic treatment need and culture-related differences among Chinese natives and foreign inhabitants. Int J Oral Sci. 2010 Sep;2(3):149-57. doi: 10.4248/IJOS10050. PMID: 21125793; PMCID: PMC3475603. 10. Piancino MG, Talpone F, Dalmasso P, Debernardi C, Lewin A, Bracco P. Reverse-sequencing chewing patterns before and after treatment of children with a unilateral posterior crossbite. Eur J Orthod. 2006 Oct;28(5):480-4. doi: 10.1093/ejo/cjl014. Epub 2006 Jun 13. PMID: 16772316. 11. Inada E, Saitoh I, Ishitani N, Iwase Y, Yamasaki Y. Normalization of masticatory function of a scissors- bite child with primary dentition: a case report. Cranio. 2008 Apr;26(2):150-6. doi: 10.1179/crn.2008.020. PMID: 18468275. 12. Makino E, Nomura M, Motegi E, Iijima Y, Ishii T, Koizumi Y, Hayashi M, Sueishi K, Kawano M, Yanagisawa S. Effect of orthodontic treatment on occlusal condition and masticatory function. Bull Tokyo Dent Coll. 2014;55(4):185-97. doi: 10.2209/tdcpublication.55.185. PMID: 25477036. 13. Henrikson T, Ekberg E, Nilner M. Can orthodontic treatment improve mastication? A controlled, prospective and longitudinal study. Swed Dent J. 2009;33(2):59-65. PMID: 19728577. 14. Ashok S, Batra P, Sharma K, Raghavan S, Talwar A, Srivastava A, Duggal I. An assessment of masticatory efficiency and occlusal load distribution in adolescent patients undergoing orthodontic treatment with functional jaw orthopedics: A prospective cohort study. J Stomatol Oral Maxillofac Surg. 2023 Dec;124(6S2):101570. doi: 10.1016/j.jormas.2023.101570. Epub 2023 Jul 26. PMID: 37507010. 15. Lee SH, Fang ML, Choi YJ, Yu HS, Kim JH, Hu KS, Lee KJ. Changes in masticatory performance during the retention period following 4-premolar mailto:rbabazadehkhoushrodi@gmail.com mailto:Bersabzevari@proton.me mailto:Fatemiarezoo@gmail.com mailto:m.soleimani@abzums.ac.ir mailto:s.sajedi@shahed.ac.ir Masticatory performance, orthodontic treatment and quality of life Eur J Transl Myol 34 (1) 12101, 2024 doi: 10.4081/ejtm.2024.12101 - 6 - extraction and non-extraction orthodontic treatment. Clin Oral Investig. 2023 Jun;27(6):2609- 2619. doi: 10.1007/s00784-022-04817-y. Epub 2022 Dec 20. PMID: 36538093. 16. Maurya RK, Bhardwaj P, Singh H, Mitra R, Nakra O, Mishra HA. Evaluation of pre- and post- treatment masticatory and bite force efficiency in patients undergoing fixed orthodontic treatment and orthognathic surgery using T-Scan Novus occlusal analysis: A factorial randomized controlled trial. Natl J Maxillofac Surg. 2022 Sep-Dec;13(3):376- 383. doi: 10.4103/njms.njms_48_22. Epub 2022 Dec 10. PMID: 36683942; PMCID: PMC9851354. 17. Ni J, Song S, Zhou N. Impact of surgical orthodontic treatment on quality of life in Chinese young adults with class III malocclusion: a longitudinal study. BMC Oral Health. 2019 Jun 13;19(1):109. doi: 10.1186/s12903-019-0782-9. PMID: 31196054; PMCID: PMC6567538. 18. Alanko O, Tuomisto MT, Peltomäki T, Tolvanen M, Soukka T, Svedström-Oristo AL. A longitudinal study of changes in psychosocial well-being during orthognathic treatment. Int J Oral Maxillofac Surg. 2017 Nov;46(11):1380-1386. doi: 10.1016/j.ijom.2017.05.004. Epub 2017 Jun 1. PMID: 28579266. 19. Huang S, Chen W, Ni Z, Zhou Y. The changes of oral health-related quality of life and satisfaction after surgery-first orthognathic approach: A longitudinal prospective study. Head & Face medicine. 2016;12(1):1-7. 10.1186/s13005-015- 0098-1 20. Antoun JS, Fowler PV, Jack HC, Farella M. Oral health-related quality of life changes in standard, cleft, and surgery patients after orthodontic treatment. Am J Orthod Dentofacial Orthop. 2015 Oct;148(4):568-75. doi: 10.1016/j.ajodo.2015.03.028. PMID: 26432312. 21. Logatskaia EB. [Gum use efficacy evaluation for chewing muscular system stimulation during orthodontic treatment]. Stomatologiia (Mosk). 2009;88(1):61-3. Russian. PMID: 19365351. 22. Yamaguchi H, Tanaka Y, Sueishi K, Sebata M, Uchiyama T, Saito C, Sigematsu T. Changes in oral functions and muscular behavior due to surgical orthodontic treatment. Bull Tokyo Dent Coll. 1994 Feb;35(1):41-9. PMID: 7923510. 23. Changsiripun C, Pativetpinyo D. Masticatory function after bite-raising with light-cured orthodontic band cement in healthy adults. Angle Orthod. 2020 Mar;90(2):263-268. doi: 10.2319/021519-112.1. Epub 2019 Aug 30. PMID: 31469594; PMCID: PMC8051233. 24. Piancino MG, Talpone F, Vallelonga T, Frongia G, Debernardi CL, Bracco P. Slow or rapid palatal expansion for early treatment of unilateral posterior crossbite? Evaluation of the reverse chewing cycles correction. Prog Orthod. 2010;11(2):138-44. doi: 10.1016/j.pio.2010.09.006. Epub 2010 Oct 8. PMID: 20974450. Disclaimer All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher. Submission: November 16, 2023 Revision received: December 26, 2023 Accepted for publication: December 27, 2023 Results