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Perception of malocclusion and school performance in adolescents: a systematic review

Abstract

This study aimed to assess the potential association between perception malocclusion and school performance in children and adolescents. An electronic search was performed in ten databases. Based on the PECO acronym (Population, Exposition, Comparator, and Outcome), the eligibility criteria included observational studies that compared the school performance of children and adolescents with and without the perception of malocclusion. There were no restrictions on the language or year of publication. Two reviewers selected the studies, extracted the data, and assessed the risk of bias by using the Joanna Briggs Institute tool for cross-sectional studies. School performance was measured by analyzing student grades; levels of absenteeism; and child or adolescent self-perception and/or the perception of parents, guardians, close friends, and teachers regarding the impact of malocclusion on school performance. The data were described narratively/descriptively. The search resulted in 3,581 registers, of which eight were included in the qualitative synthesis. These studies were published between 2007 and 2021. Two studies concluded that there was no significant association between school performance and perception of malocclusion, five studies found that only some of the children with malocclusion had their school performance affected, and one study concluded that there was a significant association between perception of malocclusion and low school performance. Considering all variables and the very low certainty of evidence, the perception of malocclusion seems to negatively impact school performance when associated with external and subjective factors. Further studies using additional measurement standards are required.

Academic Performance; Adolescent; Child; Dental Occlusion

Introduction

Individuals undergo several physical and emotional changes from birth to adulthood.11. World Health Organization. Global accelerated action for the health of adolescents (AA-HA!): guidance to support country implementation. Geneva: World Health Organization; 2017. Children and adolescents show a high worldwide prevalence of malocclusion.22. Lombardo G, Vena F, Negri P, Pagano S, Barilotti C, Paglia L, et al. Worldwide prevalence of malocclusion in the different stages of dentition: A systematic review and meta-analysis. Eur J Paediatr Dent. 2020 Jun;21(2):115- This is associated with multiple factors such as dental caries, pulpal and periapical lesions, dental trauma, abnormality of development, and oral habits.33. Zou J, Meng M, Law CS, Rao Y, Zhou X. Common dental diseases in children and malocclusion. Int J Oral Sci. 2018;10(1):7. https://doi.org/10.1038/s41368-018-0012-3
https://doi.org/10.1038/s41368-018-0012-...
Moreover, on its own, facial growth from childhood to adolescence is unable to correct most of the malocclusions of primary dentition.22. Lombardo G, Vena F, Negri P, Pagano S, Barilotti C, Paglia L, et al. Worldwide prevalence of malocclusion in the different stages of dentition: A systematic review and meta-analysis. Eur J Paediatr Dent. 2020 Jun;21(2):115-

Malocclusions constitute oral changes with a global prevalence of 39% among adolescents.44. Ghafari M, Bahadivand-Chegini S, Nadi T, Doosti-Irani A. The global prevalence of dental healthcare needs and unmet dental needs among adolescents: a systematic review and meta-analysis. Epidemiol Health. 2019;41:e2019046. https://doi.org/10.4178/epih.e2019046
https://doi.org/10.4178/epih.e2019046...
In some phases of their development, children and adolescents spend a considerable number of years in schools and other education and training institutions.11. World Health Organization. Global accelerated action for the health of adolescents (AA-HA!): guidance to support country implementation. Geneva: World Health Organization; 2017. The presence of oral disorders may affect the school life of these individuals.55. Almeida RF, Leal SC, Medonca JG, Hilgert LA, Ribeiro AP. Oral health and school performance in a group of schoolchildren from the Federal District, Brazil. J Public Health Dent. 2018 Sep;78(4):306-12. https://doi.org/10.1111/jphd.12273
https://doi.org/10.1111/jphd.12273...
,66. Ruff RR, Senthi S, Susser SR, Tsutsui A. Oral health, academic performance, and school absenteeism in children and adolescents: A systematic review and meta-analysis. J Am Dent Assoc. 2019 Feb;150(2):111-121.e4. https://doi.org/10.1016/j.adaj.2018.09.023
https://doi.org/10.1016/j.adaj.2018.09.0...
Some explicit and extreme malocclusions may also be related to bullying in childhood and adolescence.77. Tristão SK, Magno MB, Pintor AV, Christovam IF, Ferreira DM, Maia LC, et al. Is there a relationship between malocclusion and bullying? A systematic review. Prog Orthod. 2020 Sep;21(1):26. https://doi.org/10.1186/s40510-020-00323-7
https://doi.org/10.1186/s40510-020-00323...

There is evidence that certain oral conditions, such as caries, periodontal disease, tooth loss, and orofacial pain, may negatively affect oral health-related quality of life88. Haag DG, Peres KG, Balasubramanian M, Brennan DS. Oral conditions and health-related quality of life: a systematic review. J Dent Res. 2017 Jul;96(8):864-74. https://doi.org/10.1177/0022034517709737
https://doi.org/10.1177/0022034517709737...
,99. Oghli I, List T, Su N, Häggman-Henrikson B. The impact of oro-facial pain conditions on oral health-related quality of life: a systematic review. J Oral Rehabil. 2020 Aug;47(8):1052-64. https://doi.org/10.1111/joor.12994
https://doi.org/10.1111/joor.12994...
and school performance.1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
However, the primary evidence in the literature on the role of malocclusion in the school performance of children and adolescents has not yet been gathered into secondary studies. Thus, the present systematic review aimed to investigate and expose the existing scientific evidence about the impact of the perception of malocclusion on children and adolescents’ school performance.

Methodology

Protocol registration

The protocol of this systematic review was described according to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines1111. Shamseer L, Moher D, Clarke M, Ghersi D, Liberati A, Petticrew M, et al. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation. BMJ. 2015 Jan;350 jan02 1:g7647. https://doi.org/10.1136/bmj.g7647
https://doi.org/10.1136/bmj.g7647...
and registered in the International Prospective Register of Systematic Reviews database under number CRD42020172295 (https://www.crd.york.ac.uk/prospero/). Moreover, this systematic review was reported according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines1212. Page MJ, Moher D, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. PRISMA 2020 explanation and elaboration: updated guidance and exemplars for reporting systematic reviews. BMJ. 2021 Mar;372(160):n160. https://doi.org/10.1136/bmj.n160
https://doi.org/10.1136/bmj.n160...
and conducted according to the norms of the Joanna Briggs Institute manual for Evidence Synthesis1313. Aromataris E, Munn Z, editors. JBI Manual for evidence synthesis. JBI; 2020. and according to the Conducting Systematic Reviews and Meta-Analyses of Observational Studies of Etiology guidelines.1414. Dekkers OM, Vandenbroucke JP, Cevallos M, Renehan AG, Altman DG, Egger M. COSMOS-E: guidance on conducting systematic reviews and meta-analyses of observational studies of etiology. PLoS Med. 2019 Feb;16(2):e1002742. https://doi.org/10.1371/journal.pmed.1002742
https://doi.org/10.1371/journal.pmed.100...

Research question and eligibility criteria

This systematic review aimed to answer the following guiding question based on the PECO acronym (Population, Exposition, Comparator, and Outcome): “Do children and adolescents with malocclusion present lower school performance than individuals without malocclusion?”

Inclusion criteria

Population: Children and adolescents up to 19 years old, according to the World Health Organization1515. World Health Organization. Oral health surveys: basic methods. 5th ed. World Geneva: Health Organization; 2013.

Exposition: Malocclusion perceived by the individuals and/or their parents/guardians and assessed using reliable methods, such as self-perception or dental indices

Comparator: Children and adolescents who did not report perceived malocclusion and without any diagnosed malocclusion

Outcome: School performance (grade analyses, level of absenteeism, and child or adolescent self-perception or the perception of parents, guardians, and/or teachers regarding the impact of malocclusion on school performance)

Type of study: observational studies (cross-sectional, case-control, or cohort studies)

There were no restrictions on language or year of publication.

Exclusion criteria

Studies with a sample of individuals with current or previous orthodontic treatment

Studies with a sample of syndromic individuals

Studies assessing school performance using the perception of malocclusion images by third parties

Review articles, letters to the editor or editorials, personal opinions, book chapters or books, textbooks, case reports or case series, reports, and congress abstracts

Studies with overlapping samples; when two or more studies were conducted in the same place, by the same authors, and in similar years, but published in different journals or years. In this case, the most recent study that best described the methodology and results was considered.

Sources of information and search

Electronic searches were performed in November 2020 and updated until June 2022 in the following databases: Embase, LILACS and BBO, MedLine (via PubMed), SciELO, Scopus, and Web of Science. The BDTD, EASY, and WorldCat databases were used to partially capture the “gray literature”. A manual search was also performed using a systematized analysis of the list of references of eligible studies. Medical Subject Headings, Health Sciences Descriptors, and Embase Subject Headingswere used to select keywords used in the search strategies. Synonyms and free terms were also used. Boolean operators “AND” and “OR” were used to refine the research strategy using several combinations. The search strategies for each database were based on their respective syntax rules (Table 1).

Table 1
Strategies for database search

Study selection

The search results were exported to the EndNote Web™ software (Thomson Reuters, Toronto, Canada) for cataloging and removing duplicates. The results obtained in the partial search of the “gray literature” were exported to Microsoft Word (Microsoft, Washington, USA) to manually remove duplicates. Before the selection of studies, a calibration exercise was performed when the examiners discussed the eligibility criteria and applied them to a sample of 20% of the eligible studies to determine the inter-examiner agreement.

After reaching an adequate level of agreement (kappa ≥ 0.81), the reviewers (ACC and DMP) performed a detailed analysis of the titles and abstracts of the studies, applying the inclusion and exclusion criteria mentioned above. Studies that did not meet these criteria were excluded. Next, the full texts of the eligible preliminary studies were obtained and evaluated. In this phase, the excluded studies were listed separately, specifying the reasons for their exclusion. Two eligible reviewers independently performed the entire selection process. Disagreements were resolved by consulting with a third reviewer (LRP).

Data extraction

Two reviewers (ACC and DMP) independently extracted data from eligible studies. A calibration exercise was performed to ensure consistency between the two reviewers, in which information was jointly extracted from one eligible study. A third reviewer (LRP) performed calibration. The following data were extracted: identification and characteristics of the study (author, year, country, research location, and application of ethical criteria), sample characteristics (number of participants, age group, sex distribution, and method of malocclusion analysis), and main outcome characteristics (school grades, absenteeism, relationship with bullying, and assessment of school performance by parents or teachers). In case of incomplete or insufficient data, the corresponding author was contacted via e-mail up to three times at weekly intervals.

Risk of bias assessment

Evaluation of methodological quality

The studies were assessed for the risk of individual bias using the JBI Critical Appraisal Tools for use in the JBI Critical Appraisal Checklist for Analytical Cross-Sectional Studies.1616. Moola S, Munn Z, Tufanaru C, Aromataris E, Sears K, Sfetcu R, et al. Systematic reviews of etiology and risk. In: Aromataris E, Munn Z, editors. JBI Manual for evidence synthesis. JBI; 2020. Two authors (ACC and DMP) independently assessed each domain for the risk of bias as recommended by the PRISMA statement.1212. Page MJ, Moher D, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. PRISMA 2020 explanation and elaboration: updated guidance and exemplars for reporting systematic reviews. BMJ. 2021 Mar;372(160):n160. https://doi.org/10.1136/bmj.n160
https://doi.org/10.1136/bmj.n160...

Each question could be answered as follows: “Yes,” if the study did not present biases for the domain assessed in the question; “No,” if the study presented biases for the domain assessed in the question; “Uncertain,” if the study did not provide sufficient information to assess the question bias; and “Not Applicable,” if the question did not fit in the study.

Evaluation of control statements for possible confounders and bias consideration

The control statements for possible confounders and risk of bias were evaluated based on the methodology described by Hemkens et al.1717. Hemkens LG, Ewald H, Naudet F, Ladanie A, Shaw JG, Sajeev G, et al. Interpretation of epidemiologic studies very often lacked adequate consideration of confounding. J Clin Epidemiol. 2018 Jan;93:94-102. https://doi.org/10.1016/j.jclinepi.2017.09.013
https://doi.org/10.1016/j.jclinepi.2017....
First, eligible studies that mentioned only bivariate analysis or did not report multivariate analysis were excluded from this evaluation. Second, two independent reviewers (ACC and DMP) critically appraised the remaining studies. The reviewers were blinded, and a third reviewer (LRP) was consulted in case of disagreements. Each article had the Abstract and Discussion sections analyzed in consideration of confounders using six questions which were previously established. Only the sixth question considered the Conclusion section. If the conclusion section was absent, the last paragraph of the Discussion section was considered.

Assessment of confounding factors

The confounding factors were assessed based on the methodology described by Wallach et al.1818. Wallach JD, Serghiou S, Chu L, Egilman AC, Vasiliou V, Ross JS, et al. Evaluation of confounding in epidemiologic studies assessing alcohol consumption on the risk of ischemic heart disease. BMC Med Res Methodol. 2020 Mar;20(1):64. https://doi.org/10.1186/s12874-020-0914-6
https://doi.org/10.1186/s12874-020-0914-...
It was conducted by two reviewers (ACC and DMP), independent and blinded. A third reviewer (LRP) was consulted during disagreements. All studies included in the evaluation of control statements for possible confounders and bias consideration had their Methods and Result sections analyzed. The aim was to list the variables included in each study and identify which variables were used to perform adjustment, stratification, or matching between groups.

Adjustment variables were analyzed using multivariate logistic regression analysis or Poisson’s regression. Stratification variables were those used in the sample selection to make strata. Matching variables ensured compatibility of characteristics between groups. In addition, variables considered possible confounding factors were set together in their respective confounding domains.

Summary of measurements and synthesis of results

The data collected were organized and described descriptively or narratively (qualitative synthesis) according to the findings presented in each study. School performance was measured by analyzing student grades; levels of absenteeism; and child or adolescent self-perception and/or the perception of parents, guardians, close friends, and teachers regarding the impact of malocclusion on school performance.

Certainty of evidence

Two reviewers (WAV and MTCV) independently ranked the overall strength of evidence using the Grading of Recommendations, Assessment, Development and Evaluation tool.1919. Balshem H, Helfand M, Schünemann HJ, Oxman AD, Kunz R, Brozek J, et al. GRADE guidelines: 3. Rating the quality of evidence. J Clin Epidemiol. 2011 Apr;64(4):401-6. https://doi.org/10.1016/j.jclinepi.2010.07.015
https://doi.org/10.1016/j.jclinepi.2010....
To assess the criteria in systematic reviews without meta-analyses, the authors followed the adaptations proposed by Murad et al.2020. Murad MH, Mustafa RA, Schünemann HJ, Sultan S, Santesso N. Rating the certainty in evidence in the absence of a single estimate of effect. Evid Based Med. 2017 Jun;22(3):85-7. https://doi.org/10.1136/ebmed-2017-110668
https://doi.org/10.1136/ebmed-2017-11066...

Results

Study selection

The electronic search identified 3,581 results distributed into nine electronic databases, including the “gray literature”. After removing duplicates, 3,098 results remained for the analysis. Careful reading of the titles and abstracts excluded 3,071 results. Twenty-seven registers were sought for retrieval and three were not retrieved. Twenty-four studies remained for full-text reading. At this stage, 16 studies were excluded because they did not meet the inclusion criteria. Thus, eight studies were included in the qualitative synthesis.1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...

22. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...

23. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...

24. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...

25. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...

26. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
-2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
Figure shows the details of the study selection process.

Figure
Flowchart depicting the study selection process (Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram).

Characteristics of the eligible studies

The studies were published between 2007 and 2021 and performed in five different countries: Brazil,1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...
,2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...
,2525. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...
Chile,2626. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
India,2323. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...
Mongolia,2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
and Peru.2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...
All studies reported the following ethical criteria with the approval of an ethics committee and/or application of a consent form to the research participants. The sample included 9,369 children and adolescents allocated to public and private schools. The reported ages varied between 3 and 19 years.

Malocclusion was assessed using the Dental Aesthetic Index (DAI),1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...
,2323. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...
,2626. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
self-perceived malocclusion,2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...
malocclusion exam for the presence of dentofacial features,2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...
the use of a Community Periodontal Index (CPI) probe,2525. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...
and the Index of Orthodontic Treatment Need (IOTN).2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
The tools used to measure the school performance of participants varied among grades,1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...
,2323. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...
,2626. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
,2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
self-reports by adolescents,2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...
,2525. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...
and absenteeism.2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...

Table 2 details the information of each eligible study.

Table 2
Main characteristics of the eligible studies

Summary of measurements and synthesis of results

Eight studies1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...

22. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...

23. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...

24. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...

25. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...

26. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
-2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
were included in the qualitative synthesis, and their outcomes are summarized below.

The study by Paula et al.2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...
did not show a significant association between the need for orthodontic treatment (assessed using the DAI) and school performance, with an odds ratio (OR) of 1.33 (0.87–2.03). Similarly, Julca-Ching and Carruitero2626. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
did not find a significant difference in school performance scores between young individuals with normal occlusion and those with malocclusion, regardless of severity. Furthermore, both studies highlighted the potential association between the influence of external and subjective factors, especially related to family members and socioeconomic conditions, and the impact of malocclusion on school performance.

Ortiz et al.1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
reported that some adverse oral conditions, such as malocclusion, as well as subjective and socioeconomic factors, might have impacted adolescents’ academic performance. Bernabé et al.2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...
observed that only 0.6% of the children analyzed reported some impact of malocclusion on their education, with the impact intensity ranging from mild to moderate.

In turn, Basha et al.2323. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...
found that 42% of students with malocclusion presented impact on school performance, with grades below average over the last three years. Regarding the self-perceived impact, 20% of the students reported that school performance was affected by their dental appearance. As for the perception of parents, 77% felt that the school performance of their children was affected by dental appearance, 79% of teachers reported such perception, and 32.7% of the close friends of the students analyzed mentioned such a relationship. Badrakhkhuu et al.2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
also observed that schoolchildren in Mongolia with dental crowding, a type of malocclusion, might be prone to poor academic performance, particularly in arts and physical education.

Neves et al.2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...
showed a prevalence of 8.5% in school absences due to oral problems. Lastly, Cunha et al.2525. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...
observed a significant association between malocclusion (such as accentuated overjet and open bite) and school performance, directing the measurement to school failure (OR, 1.40 (1.31–1.50)) after adjusting for confounding factors.

Table 3 shows the main outcomes and quantitative results regarding the presence of malocclusion and its impact on school performance in each eligible study.

Table 3
Main outcomes of the eligible studies

Risk of individual bias of the studies

Methodological quality of the eligible studies

Only two studies2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...
,2626. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
met all criteria from the checklist. Three studies2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...
,2323. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...
,2626. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
did not meet the fifth, sixth, and eighth question criteria because they lacked proper confounding acknowledgement and did not perform multivariate analysis to adjust for their variables, showing high potential biases in their methodology. Table 4 shows more details about the methodological evaluation of the eligible studies.

Table 4
Risk of bias assessed with the Joanna Briggs Institute Critical Appraisal Tools for use in the JBI Critical Appraisal Checklist for Analytic Cross-Sectional Studies

Evaluation of control statements for possible confounders and bias consideration

All eight eligible studies were analyzed, and three studies were excluded for mentioning only bivariate analysis or not reporting multivariate analysis. After this, five studies1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...
,2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...
,2525. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...
,2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
were included in the evaluation of control statements for possible confounders and bias consideration. Only one study2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
did not mention the term “confounding” and only two studies2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
,2828. Minayo MC. Construção de indicadores qualitativos para avaliação de mudanças. Rio de Janeiro: Ed. Fiocruz; 2009. mentioned the term “bias”. Only two studies1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2525. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...
,2828. Minayo MC. Construção de indicadores qualitativos para avaliação de mudanças. Rio de Janeiro: Ed. Fiocruz; 2009. mentioned non-adjusted variables that were not measured. The results of four studies1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...
,2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...
,2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
were possibly affected by confounding factors. Four studies2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...
,2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...
,2525. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...
,2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
reported the need for caution when interpreting their results. Only one study2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
included limitations in the Conclusion section. The results of the evaluation of the control statements for confounders and bias consideration are presented in Table 5.

Table 5
Evaluation of control statements for possible confounders and bias consideration

Assessment of confounding factors

Eighty-six variables were identified in the studies included in this analysis. They were classified into five domains: dentofacial features, school environment, sociodemographic and socioeconomic factors, residential environment, and dental services. The domain with the most variables was the dentofacial feature domain with 20 different variables. The most frequent variables were age, sex, and family income, which were present in all studies. There was high heterogeneity among all studies, as well as their variables within the school environment, residential environment, and dental services domains. Some variables had similar meanings; thus, they were set together in standardized terms for better analysis. The confounding domains identified in the eligible studies are presented in Table 6.

Table 6
Confounding domains identified in selected studies

In addition, 59 continuous and categorical variables were used as adjustment variables. Age and sex were used for adjustment in three studies and were the most commonly used variables within the adjusted variables. Only one study2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...
used stratification variables: school district and school type. Only age was used to match groups; this matching variable was present in two studies.1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...

Certainty of evidence

The certainty of evidence was classified as “very low” and downgraded due to the risk of bias, inconsistency, and indirectness (Table 7).

Table 7
Summary of findings by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) for the outcomes of the systematic review

Discussion

The present systematic review aimed to assess whether adolescents with malocclusion tend to have lower school performance than those without malocclusion. The evidence from the studies included in the qualitative synthesis suggests that this dental condition affects student performance when associated with external factors, especially those related to family members and socioeconomic conditions.

School performance can be assessed by using several indicators. The quantitative indicators relate to the grades obtained by students in evaluations, tests, and homework, the approval rate,2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...
and levels of absenteeism.2525. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...
Indicators obtained from self-perception or the perception of parents, guardians, teachers, or close friends are considered qualitative indicators because they depend on a subjective interpretation and the individual judgment of a situation.2828. Minayo MC. Construção de indicadores qualitativos para avaliação de mudanças. Rio de Janeiro: Ed. Fiocruz; 2009.Therefore, the analysis of school performance is associated with objective factors and organic, cognitive, psychological, socioeconomic, and educational factors.2929. Jackson SL, Vann WF Jr, Kotch JB, Pahel BT, Lee JY. Impact of poor oral health on children’s school attendance and performance. Am J Public Health. 2011 Oct;101(10):1900-6. https://doi.org/10.2105/AJPH.2010.200915
https://doi.org/10.2105/AJPH.2010.200915...
The eligible studies of this review showed high heterogeneity for the tools for measuring school performance among the young people assessed.

In this context, the presence of abnormal dentofacial characteristics, such as malocclusion, may negatively interfere with the school performance of individuals, as suggested by some of the eligible studies.1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...
,2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...
,2525. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...
,2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
In general, poor health conditions of students might harm their cognitive development and participation in school activities, increasing the levels of absenteeism,3030. Needham BL, Crosnoe R, Muller C. Academic failure in secondary school: the inter-related role of health problems and educational context. Soc Probl. 2004;51(4):569-86. https://doi.org/10.1525/sp.2004.51.4.569
https://doi.org/10.1525/sp.2004.51.4.569...
which corroborates the negative impact of malocclusion on school performance.1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...
,2424. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...
,2525. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...
,2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
In studies that used qualitative indicators,2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...
,2323. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...
there was a focus on the self-perception of students with malocclusion and the perception of parents, teachers, and close friends. Divergent results from the perceptions of parents and teachers to that of students and close friends showed that, in most cases, adults did not understand the situations and difficulties that children and adolescents faced in school.2323. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...

However, the neutral results of those impacts on school performance from other eligible studies2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...
,2626. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
highlighted the strong influence of external and subjective factors when dealing with different adverse situations on behavioral changes and decreased school performance, such as poor family socioeconomic conditions,3131. Mikaeloff Y, Caridade G, Billard C, Bouyer J, Tardieu M. School performance in a cohort of children with CNS inflammatory demyelination. Eur J Paediatr Neurol. 2010 Sep;14(5):418-24. https://doi.org/10.1016/j.ejpn.2010.02.003
https://doi.org/10.1016/j.ejpn.2010.02.0...
low level of education of parents or guardians,3131. Mikaeloff Y, Caridade G, Billard C, Bouyer J, Tardieu M. School performance in a cohort of children with CNS inflammatory demyelination. Eur J Paediatr Neurol. 2010 Sep;14(5):418-24. https://doi.org/10.1016/j.ejpn.2010.02.003
https://doi.org/10.1016/j.ejpn.2010.02.0...
household overcrowding,3232. Evans GW, Saegert S, Harris R. Residential Density and Psychological Health among Children in Low-Income Families. Environ Behav. 2001;33(2):165-80. https://doi.org/10.1177/00139160121972936
https://doi.org/10.1177/0013916012197293...
,3333. Maxwell LE. Home and school density effects on elementary school children: the role of spatial density. Environ Behav. 2003;35(4):566-78. https://doi.org/10.1177/0013916503035004007
https://doi.org/10.1177/0013916503035004...
and the type of school attended by the child or adolescent.2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...

Eligible studies were conducted in different countries, with major socioeconomic and cultural factors that might have influenced the results. For example, low- and middle-income countries, such as Brazil and India, still present concerns about child labor, which can affect the physical and mental health of this population.3434. Ibrahim A, Abdalla SM, Jafer M, Abdelgadir J, Vries N. Child labor and health: a systematic literature review of the impacts of child labor on child’s health in low- and middle-income countries. J Public Health (Oxf). 2019 Mar;41(1):18-26. https://doi.org/10.1093/pubmed/fdy018
https://doi.org/10.1093/pubmed/fdy018...
In poor families, it may be common to observe children and adolescents working to help their parents or relatives with monthly bills. These less privileged conditions may also be related to typical public health and social questions, which are already associated with impaired school performance: dental caries and worse oral health,3535. Rebelo MA, Vieira JMR, Pereira JV, Quadros LN, Vettore MV. Does oral health influence school performance and school attendance? A systematic review and meta-analysis. Int J Paediatr Dent. 2018 Oct;29(2):1-11. https://doi.org/10.1111/ipd.12441
https://doi.org/10.1111/ipd.12441...
altered sleep time,3636. Alfonsi V, Scarpelli S, D’Atri A, Stella G, De Gennaro L. Later School Start Time: The Impact of Sleep on Academic Performance and Health in the Adolescent Population. Int J Environ Res Public Health. 2020 Apr;17(7):2574. https://doi.org/10.3390/ijerph17072574
https://doi.org/10.3390/ijerph17072574...
and less access to proper schooling resources and equipment,3737. Panagouli E, Stavridou A, Savvidi C, Kourti A, Psaltopoulou T, Sergentanis TN, et al. School performance among children and adolescents during COVID-19 pandemic: a systematic review. Children (Basel). 2021 Dec;8(12):1134. https://doi.org/10.3390/children8121134
https://doi.org/10.3390/children8121134...
especially in the recent online study methods.3636. Alfonsi V, Scarpelli S, D’Atri A, Stella G, De Gennaro L. Later School Start Time: The Impact of Sleep on Academic Performance and Health in the Adolescent Population. Int J Environ Res Public Health. 2020 Apr;17(7):2574. https://doi.org/10.3390/ijerph17072574
https://doi.org/10.3390/ijerph17072574...

All eligible studies were cross-sectional. This type of study can lead to limitations when analyzing outcomes, as they analyze exposure and outcome at the same time, which impairs the inference of causality.3838. Carlson MD, Morrison RS. Study design, precision, and validity in observational studies. J Palliat Med. 2009 Jan;12(1):77-82. https://doi.org/10.1089/jpm.2008.9690
https://doi.org/10.1089/jpm.2008.9690...
Furthermore, observational studies do not present permutability between their study groups, because of the lack of randomized variables.3939. Hernán MA, Robins JM. Estimating causal effects from epidemiological data. J Epidemiol Community Health. 2006 Jul;60(7):578-86. https://doi.org/10.1136/jech.2004.029496
https://doi.org/10.1136/jech.2004.029496...
On the other hand, as the focus is on malocclusions, it may favor a cause-and-effect interpretation, as they can be considered as inborn characteristics of the individuals.3838. Carlson MD, Morrison RS. Study design, precision, and validity in observational studies. J Palliat Med. 2009 Jan;12(1):77-82. https://doi.org/10.1089/jpm.2008.9690
https://doi.org/10.1089/jpm.2008.9690...
However, it is still not a longitudinal design to better estimate the exact correlation of the variables studied. This could also underestimate the role of confounding factors.

Some potential biases in the eligible studies should be acknowledged. First, the performance of only bivariate analysis or the lack of multivariate analysis in observational studies are common and dangerous pitfalls. Observational studies have a high risk of presenting several uncontrolled confounders, which limits their results.1414. Dekkers OM, Vandenbroucke JP, Cevallos M, Renehan AG, Altman DG, Egger M. COSMOS-E: guidance on conducting systematic reviews and meta-analyses of observational studies of etiology. PLoS Med. 2019 Feb;16(2):e1002742. https://doi.org/10.1371/journal.pmed.1002742
https://doi.org/10.1371/journal.pmed.100...
Multivariate analysis is a reliable statistical test to provide proper adjustment of variables, reducing the potential confounding influence.3838. Carlson MD, Morrison RS. Study design, precision, and validity in observational studies. J Palliat Med. 2009 Jan;12(1):77-82. https://doi.org/10.1089/jpm.2008.9690
https://doi.org/10.1089/jpm.2008.9690...
Secondly, this reduction is unfortunately not absolute, and the interpretation of results should be performed with caution. Although there was acceptable prudence in selected studies regarding this caution, they lacked proper acknowledgement of non-adjusted variables and inclusion of limitations in the Conclusion section.

The confounding domains identified in the selected studies brought up some confounders to be considered in the association between malocclusion and school performance. It is important to highlight them because of their potential roles as causes, effects, or coincidences without any relationship. However, inferences about the roles of each variable are limited to be made based on observational studies.1414. Dekkers OM, Vandenbroucke JP, Cevallos M, Renehan AG, Altman DG, Egger M. COSMOS-E: guidance on conducting systematic reviews and meta-analyses of observational studies of etiology. PLoS Med. 2019 Feb;16(2):e1002742. https://doi.org/10.1371/journal.pmed.1002742
https://doi.org/10.1371/journal.pmed.100...
Therefore, further studies with longitudinal and controlled designs are necessary to better understand this association.

This review had a few limitations. First, different observational designs might have affected the presence of divergences among the individual results of the studies, especially regarding the absence of standardization of the tools for assessing malocclusions. Most studies1010. Ortiz FR, Ardenghi TM, Paiva SM, Maroneze MC, Pordeus IA. Impact of oral conditions and subjective factors on academic performance. Pesqui Bras Odontopediatria Clin Integr. 2021;21:e0233. https://doi.org/10.1590/pboci.2021.083.
https://doi.org/10.1590/pboci.2021.083...
,2222. Paula JS, Ambrosano GM, Mialhe FL. Oral disorders, socioenvironmental factors and subjective perception impact on children’s school performance. Oral Health Prev Dent. 2015;13(3):219-26. https://doi.org/10.3290/j.ohpd.a32672
https://doi.org/10.3290/j.ohpd.a32672...

23. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...

24. Neves ET, Firmino RT, Perazzo MF, Gomes MC, Martins CC, Paiva SM, et al. Absenteeism among preschool children due to oral problems. J Public Health (Berl). 2016;24(1):65-72. https://doi.org/10.1007/s10389-015-0697-0
https://doi.org/10.1007/s10389-015-0697-...

25. Cunha IP, Pereira AC, Meneghim MC, Frias AC, Mialhe FL. Association between social conditions and oral health in school failure. Rev Saude Publica. 2019 Dec;53:108. https://doi.org/10.11606/S1518-8787.2019053001457
https://doi.org/10.11606/S1518-8787.2019...

26. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
-2727. Badrakhkuu N, Matsuyama Y, Araki MY, Yasuda YU, Ogawa T, Tumurkhuu T, et al. Association between malocclusion and academic performance among mongolian adolescents. Front Dent Med. 2021;1:623768. https://doi.org/10.3389/fdmed.2020.623768
https://doi.org/10.3389/fdmed.2020.62376...
were based on dental professionals’ perception measurements to assess malocclusions, such as the DAI, malocclusion exam, IOTN, and the use of a CPI probe. Only one study2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...
subjectively measured malocclusion using Child Oral Impacts on Daily Performances, with the self-perception of individuals. Subjective measurements may be subject to the influence of individual experiences, considering that the same condition may be understood differently by each individual. Moreover, the assessment of several school performance indicators was verified among the studies and some of them2121. Bernabé E, Flores-Mir C, Sheiham A. Prevalence, intensity and extent of oral impacts on daily performances associated with self-perceived malocclusion in 11-12-year-old children. BMC Oral Health. 2007 May;7(1):6. https://doi.org/10.1186/1472-6831-7-6
https://doi.org/10.1186/1472-6831-7-6...
,2323. Basha S, Mohamed RN, Swamy HS, Parameshwarappa P. Untreated gross dental malocclusion in adolescents: psychological impact and effect on academic performance in school. Oral Health Prev Dent. 2016;14(1):63-9. https://doi.org/10.3290/j.ohpd.a35003
https://doi.org/10.3290/j.ohpd.a35003...
,2626. Julca-Ching K, Carruitero MJ. Impact of the need for orthodontic treatment on academic performance, self-esteem and bullying in schoolchildren. J Oral Res. 2019;8(2):99-103. https://doi.org/10.17126/joralres.2019.016
https://doi.org/10.17126/joralres.2019.0...
did not perform analyses to deal with confounding factors associated with the outcomes. Thus, owing to the lack of measurement standards, the results may not reflect the true impact of malocclusion on school performance. Further studies with the application of more standardized and better-designed methodologies are encouraged to address such limitations. Another significant limitation worth noting is that malocclusion may relate to other factors that can also affect school performance, such as bullying.4040. Agel M, Marcenes W, Stansfeld SA, Bernabé E. School bullying and traumatic dental injuries in East London adolescents. Br Dent J. 2014 Dec;217(12):E26. https://doi.org/10.1038/sj.bdj.2014.1123
https://doi.org/10.1038/sj.bdj.2014.1123...
The lack of analysis of confounding factors was a bias identified in part of the eligible studies and deserves attention when interpreting the results.

Some strengths of this systematic review must be highlighted, such as its preparation according to specific instructions1212. Page MJ, Moher D, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. PRISMA 2020 explanation and elaboration: updated guidance and exemplars for reporting systematic reviews. BMJ. 2021 Mar;372(160):n160. https://doi.org/10.1136/bmj.n160
https://doi.org/10.1136/bmj.n160...
and caution to minimize biases. Moreover, this is the first systematic review to specifically assess the impact of malocclusion on the school performance of children and adolescents. The evidence summarized may be useful for the decision-making of governments and school administrators, especially regarding the need to establish a partnership between schools and dental professionals in an attempt to provide better oral health and higher access to dental treatments, such as orthodontic treatment to correct malocclusions.

Conclusion

The very low certainty evidence suggests that the perception of malocclusion negatively affects the school performance of students when associated with external factors, especially those related to family members and socioeconomic conditions. Considering the limitations of this systematic review, the results may not accurately reflect the impact of malocclusion on school performance. Nevertheless, the findings provide important data to encourage health actions toward the development of oral health care programs for students, aiming to improve their quality of life physically and psychologically, and consequently, their school performance.

Acknowledgment

This study was partially financed by Capes (Finance Code 001). We are thankful for the support from CNPq and Fapemig.

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Publication Dates

  • Publication in this collection
    28 Apr 2023
  • Date of issue
    2023

History

  • Received
    11 Feb 2022
  • Accepted
    17 Oct 2022
  • Reviewed
    8 Nov 2022
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