Oral hygiene, dental caries, and periodontal status in the migrant population. A systematic review, a 10-year study

Abstract

A migrant is a person who moves away from his or her place of habitual residence, whether within a country or across an international border, temporarily or permanently, and for a variety of reasons. Migrant population presents significant challenges in maintaining optimal oral health, because of the limitation in access to a balanced diet, excessive consumption of processed foods or those with a high percentage of sugars, as well as the cost of acquiring hygiene items such as toothbrushes or toothpaste, coupled with the lack of access to public services, they comprise a highly vulnerable population to developing oral disease. Objective. This study aimed to identify and synthesize the oral health characteristics of migrant populations as reported in the literature. A search was conducted for articles that included studies that had some type of report on the oral health status of a migrant population. A bibliographic search was performed in the PubMed, ScienceDirect and Scopus databases from 2016 to 2025 using the keywords: “immigrants”, “emigration”, “oral health”, “dental caries” and “periodontal disease”. To perform the risk of bias analysis, the Joanna Briggs Institute tool for cross-sectional studies was used. Results. Twenty-one studies were selected, nine studies were conducted on migrants of multiple nationalities, in 10 studies (45.4%), oral health characteristics were self-reported by participants, whereas in 11 studies (54.6%), assessments were conducted by a qualified examiner. Based on the reported caries indices, caries experience among the studied populations ranged from 5.5 to 30.9 affected teeth, Regarding the presence of periodontal disease, seven studies reported findings ranging from gingival bleeding to positive results indicating the loss of dental support, and oral lesions were only reviewed in two studies, the most common lesions reported were leukoplakia and fibrous lesions. Conclusion. The evidence suggests that migrants try to maintain the custom of having a diet as natural as possible, but this may be diminished by the economic factor or by a process of resilience. The migrant individuals are characterized by limited access to health services, coupled with their limited economic resources, which makes them susceptible to developing oral diseases. This is corroborated by the high incidence of dental caries and bleeding gums. One of the main limitations of the study was the period (2016–2025) that was selected, which does not represent the totality of what has been published on the subject.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13005-025-00527-4.

Introduction

Oral health is defined as a condition of the mouth, teeth, and orofacial structures that allow essential functions such as eating, breathing, and speaking. It also encompasses psychosocial aspects such as self-confidence, well-being, and the ability to socialize and do work duties without pain, discomfort or embarrassment [1].

Poor oral health can cause systemic problems through the spread of pathogens into the bloodstream, promoting the development of diseases ranging from immunological to cardiac and neurological disorders, among others [2, 3].

The World Health Organization has proposed dental caries, periodontal disease, tooth loss, trauma, oral cancer, and injuries caused by Human immunodeficiency virus (HIV) as global public health problems [4]. The reports provided by Global, Regional, and National Levels and Trends in Burden of Oral Conditions from 1990 to 2017, mention that the prevalence of untreated caries in adult dentition is between 20 and 24 years, for severe periodontal disease the peak age is from 60 to 64 years and finally, the absence of teeth is observed between 85 and 89 years. These data change geographically depending on population size; India, China, Indonesia, Brazil, and the United States are among the 10 countries with the greatest need for dental treatment [5]. It has been mentioned that among the leading risk factors for the development of caries, periodontal disease and tooth loss are inadequate oral hygiene, sugar consumption, tobacco and alcoholism [6, 7].

Migration is the movement of people from their place of birth to a new location; between 2000 and 2020, the world’s immigrant population increased from 173 million (2.8% of the total world population) to 281 million (3.6% of the total world population) [8].

Maintaining oral health can be achieved through daily tooth brushing, frequent use of fluoride products such as toothpaste or topical applications, and controlled sugar consumption; all of the above can be achieved through education. However, the migrant population presents great challenges in maintaining optimal oral health, because of the limitation in access to a balanced diet, excessive consumption of processed foods or those with a high percentage of sugars, as well as the cost of acquiring hygiene items such as toothbrushes or toothpaste, coupled with the lack of access to public services, they are an exceptionally vulnerable population prone to develop some oral disease [9, 10].

Some of the reasons why people are forced to leave their homes is because they have the need to work, seek better wages, study or reunite with their families, others feel they must leave due to poverty, natural disasters, political instability, gang violence or other serious circumstances that exist in their country of origin [11, 12].

Failure to identify dental care needs in the migrant population can negatively affect their overall health, which in turn could lead to complications during their transit or while performing work activities, all these factors prompted us to do this study. This study aimed to identify the oral health characteristics of migrant populations as reported in the literature through a systematic review, making the following research question: What are the oral characteristics and/or dental treatment needs reported in the literature regarding the migrant population worldwide? This will enable us, as health professionals, to recognize their oral treatment needs and provide specialized care accordingly. To carry out the study, a bibliographic search was performed in the PubMed, ScienceDirect and Scopus databases using the keywords: “immigrants”, “emigration”, “oral health”, “dental caries” and “periodontal disease”.

Materials and methods

Research question

What are the oral characteristics and/or dental treatment needs reported in the literature regarding the migrant population worldwide?

Inclusion criteria

• Original studies that report some description of migrant subjects’ oral health status.

• Studies conducted in adults (over 18 years of age).

• Studies in English or Spanish.

Elimination criteria

• Studies whose methodology includes results of prevention protocols but do not include data before and after the intervention.

• Studies focused on quality-of-life instruments.

• Studies whose methodology does not reflect clear information on oral health status.

• Database-based studies where the results are predictive.

• Qualitative studies.

Search strategy

This study was conducted over a 10-year period to ensure that the information obtained is recent and reflects the current situation of the population studied; a 10-year range filtered search (2016 to 2025) was performed in the following databases: PubMed, ScienceDirect, and Scopus. The search utilized the following keywords and Boolean operators: (“immigrants” OR “emigration”) AND (“oral health” OR “dental caries” OR “periodontal disease”) (Search: (“immigrants” OR “emigration”) AND (“oral health” OR “dental caries” OR “periodontal disease”). Filters: in the last 10 years, Humans). (full electronic search strategy supplementary material) The search was conducted by title, abstract, and keywords, this review was conducted in accordance with the PRISMA guidelines.

Selection of studies

For the selection of studies, an initial filtering process was conducted based on titles and abstracts. The title or abstract was checked to ensure that it contained any of the keywords established to identify studies as potential candidates for inclusion and were placed in a bibliographic manager. (Mendeley Desktop 1.19.8, Elsevier, Atlanta, Ga., USA) for subsequent extensive review. The entire process was carried out independently by two researchers (García-Calderon AG and Cuevas-Gonzalez MV). (Cohen’s kappa statistic 0.85) In case of disagreement, a third researcher (Cuevas-Gonzalez JC) independently intervened in the process. During this stage, each article was reviewed in full to determine whether its objectives and methodology aligned with those established for this systematic review. This process enabled the identification of all studies to be included.

Risk of bias

To perform the risk of bias analysis, the Joanna Briggs Institute tool for cross-sectional studies was used. The tool consists of a questionnaire made up of 8 questions focused on Q1) criteria for inclusion in the sample, Q2) study subjects, Q3) exposure measured, Q4) criteria used for measurement of the condition, Q5) confounding factors, Q6) strategies to deal with confounding factors, Q7 outcomes measured in a valid way, and Q8) appropriate statistical analysis used [13].

Data extraction and analysis

Once the studies were selected, information such as author, year, country of study, type of oral examination, oral hygiene conditions, presence of caries, periodontal status, and conclusions related to the oral health of the study subjects was collected. All information was inputted into the SPSS V. 30 statistical program to perform a descriptive analysis of the data, reporting frequencies of the qualitative variables.

Results

Search strategy

The proposed search strategy yielded a total of 315 studies. An initial search was conducted by title and abstract to identify the proposed keywords, selecting 82 potential studies that met the selection criteria. These studies were then uploaded into a bibliographic manager (Mendeley Desktop 1.19.8, Elsevier, Atlanta, Ga., USA) for subsequent full-text review. After conducting the full-text review of the 82 studies, a total of 40 were eliminated because they did not meet the previously established criteria. Twenty-one studies were selected for the final analysis (Fig.1) [8, 14–33].

Fig. 1.

PRISMA 2020 flow diagram

Risk of bias

To analyze the risk of bias, the tool for cross-sectional studies was used. This tool includes eight questions that evaluate key methodological aspects such as sample selection, analysis of results, and consideration of confounding factors. The analysis revealed that while most studies adequately reported on sample selection, inclusion criteria, and result analysis, they frequently failed to address confounding factors—reflected in questions 5 and 7 of the tool. Consequently, most studies were classified as having a moderate risk of bias (Table 1).

Table 1.

Risk of bias results, it is observed that most studies do not include the analysis of confounding variables. The green color means that the data was identified in the study, the yellow color means that the study does not present the data or it is not required by the type of study

Data extraction

Among the selected studies, the United States was the most common country where studies were conducted, accounting for 40.9% (nine studies) of the total, the origin of the migrant population was difficult to determine, with most studies reporting it as a population of multiple nationalities. The information regarding oral characteristics was self-reported in 10 studies (45.4%), while in 11 studies (54.6%), the subjects were examined by a professional. The total population studied across the selected studies 56,154 subjects, this data is excluding a study carried out by Sano Y (2019) in which 2,376,544 subjects were analyzed. The study with the largest population was conducted by Sano Y et al., which included over 2 million migrant subjects due to their review of national databases.

Regarding information on oral characteristics, six studies reported good to excellent oral hygiene, two reported poor oral hygiene, and two performed gingival plaque indices. About the presence of carious lesions, eight studies reported using the decayed, missing, and filled permanent teeth or surfaces (DMFS) and Decayed, Missing, and Filled Teeth (DMFT) indices, reporting a caries experience ranging from 5.5 to 30.9 number ofteeth. Two studies reported the percentage of carious lesions without mentioning any index. Regarding the presence of periodontal disease, seven studies reported findings ranging from gingival bleeding to positive results indicating the loss of dental support. Concerning tooth absence, seven studies documented the absence of 1 to 8 teeth or the presence of edentulism. Oral lesions were only reviewed in two studies, the most common lesions reported were leukoplakia and fibrous lesions.

Finally, when analyzing risk factors, five studies reported positive results for tobacco use, whether smoked or chewed, while three studies identified information about alcohol consumption (Tables 2 and S3 supplementary material).

Table 2.

Descriptive results of the total studies analyzed

Methodological characteristics of the studies					Oral status					Risk factors		Ref.
Author	Country where the study was conducted	Nationality of the study subjects	Type of oral review	Number of subjects included in the study	Oral hygiene	Caries	Periodontal disease	Missing teeth	Oral lesion	Tabacco	Alcohol
Mejia GC (2023)	Australia	Multiple nationalities	Self-reported	15,727	Excellent/very good 71.5%	NM	NM	NM	NM	NM	NM	[14]
Raskin SE (2022)	USA	Multiple nationalities	Self-reported	327	Poor (58.2%)	NM	NM	1–8 teeth (57.2%)	NM	Current 9.4%	31.90%	[15]
Saraswat N (2022)	Australia	Indian	Self-reported	164	Excellent or good 65.8%	NM	NM	NM	NM	Yes 6%	Yes 64%	[16]
Luo H (2022)	USA	Lartinos	Professional examination	5,709	NM	NM	Moderate 43.1%	less than 7 tooth loss 65.2%	NM	NM	NM	[17]
Velázquez-Cayón RT (2022)	Spain	Multiple nationalities	Professional examination	878	NM	NM	CPI = 3 (63.5%)	NM	Fibrous lesions	NM	NM	[8]
Traisuwan W (2021)	Thailand	Multiple nationalities	Professional examination	220 (pregnant women)	NM	88.90%	NM	21.60%	NM	NM	NM	[18]
Laniado N (2021)	USA	Latinos	Professional examination	4,459	NM	DMFS index 30.9	NM	NM	NM	Curret 20.3%	NM	[19]
Delgado angulo E (2020)	London	Multiple nationalities	Self-reported	13,373	NM	NM	NM	9.20%	NM	NM	NM	[20]
Hamid, R.N. (2020)	Iraq	Multiple nationalities	Professional examination	200	Gingival index 0.8 ± 0.7	DMFT index 10.7	NM,	NM	NM	NM	NM	[21]
Wu B (2020)	USA	Chinese	Self-reported	430	Excellent or good 53.82%	NM	NM	Loss six or more teeth 36.08%	NM	NM	NM	[22]
Sano Y (2019)	Canada	Multiple nationalities	Self-reported	2,320,170	Good (79.6%)	NM	NM	NM	NM	Daily 2.26%	85%	[23]
Rota K (2019)	USA	Albanian	Self-reported	266	Good (66.7%)	NM	NM	NM	NM	NM	NM	[24]
Pullen E (2019)	USA	Mexican	Self-reported	332	NM	NM	Bleeding 36.99%	Less than 5 tooth loss 0.86%	NM	NM	NM	[25]
Delgado angulo E (2018)	London	Multiple nationalities	Professional examination	1910	NM	DMFT 8.9	NM	NM	NM	NM	NM	[26]
Aarabi G (2018)	Germany	Multiple nationalities	Professional examination	112	Approximal Plaque Index 55.3%	DMFT index 24.8	Papillary bleending index 46.3%	NM	NM	NM	NM	[27]
Wilson FA (2018)	USA	Multiple nationalities	Professional examination	3,380	NM	Caires 38%	Periodontal disease 50.5%	NM	NM	NM	NM	[28]
Ali AK (2017)	India	Multiple nationalities	Professional examination	2,163	NM	NM		NM	Leukoplakia 14.75%	Yes 90.2%	NM	[29]
Mattila A (2016)	Finland	Multiple nationalities	Self-reported	38	NM	63%	Bleeding on brushing 68%	NM	NM	NM	NM	[30]
Jung M (2017)	Asian American	Asian	Professional examination	1288	Fair (49.8%)	NM	NM	NM	NM	NM	NM	[31]
Liu Y (2016)	USA	Multiple nationalities	Self-reported	9,756	Excellent or good 40.47%	NM	NM	NM	NM	NM	NM	[32]
Olerud E (2016)	Sweden	Multiple nationalities	professional examination	42	NM	DMFT index 5.5. − 6	Gingival pockets of 6 mm, (33%)	Edentulism 17%	NM	NM	NM	[33]

Discussion

Among the main findings of this study, it is worth highlighting that the indices used to measure caries experience in different migrant populations ranged from 5.5 to 30.9 affected teeth. Regarding the condition of the tooth-supporting tissues, gingival bleeding was particularly notable, along with the absence of dental organs, where the loss of 1 to 8 teeth was observed. When a person decides or is forced to leave their home in search of better living conditions, they face numerous challenges, including limited access to health services. Access to healthcare should encompass availability, accessibility, the alignment between the organization of health services and the characteristics of potential users, the associated costs, and the acceptability of these services; An important part of the services include certain skills and/or capacities of the subjects, like the perception of needing health services [34]. In our opinion, this characteristic represents one of the primary limitations, according to the results presented by various authors included in this study self-assessments of different migrant populations indicated their perception of oral health ranged from very good to excellent [14, 16, 22, 32]. Although these data may be correct, corroboration by a professional is necessary to avoid underdiagnosis of oral lesions in this population.

As mentioned in the introduction, inadequate hygiene is a risk factor shared by dental caries, periodontal disease and tooth loss [6]. It has been mentioned in recent publications that dental caries could be a disease related to people with scarce economic resources, Cope AL et al. mentioned that in the United Kingdom, 6.5% of the population has experienced “hygiene poverty” where there has been a lack of basic oral hygiene items such as toothbrushes and toothpaste, and they have indeed mentioned that these products are not among the priorities to acquire [35]. A strikingly similar phenomenon can be observed in the migrant population, where people prioritize purchasing food over oral hygiene products, which can be expensive, resulting in the development of caries and periodontal disease.

According to the findings reported in the included studies, when analyzing the caries experience index (DMFS and DMFT), the highest values of teeth with caries experience ranging from 24.8 to 30.9; one of the main reasons for this is the cost of seeking healthcare services and the lack of access to health insurance. Another possible reason is the culture of various migrant populations, who tend not to prioritize oral health [27] Laniado N et al. conducted a study in a Latin American population from multiple countries of origin and identified caries rates of 30.9, although carious lesions are of multifactorial etiology in this type of population, the place of origin becomes differential, with South American countries being more affected (DMFS 40.5) and Cuba (DMFS 43.8). Alternatively, the variable of the time of residence in the new country is raised, since the younger the person who has arrived in the country, the more access they can acquire to the health systems and less responsibility falls on the social environment or family. (‘familismo’) [19].

One of the key factors contributing to the presence of oral lesions in the migrant population is undoubtedly their diet. A very interesting study carried out by Berggreen-Clausen A et al., showed that the migrant population may have a deep-rooted habit of acquiring simple and natural foods, for which they acquire strategies that allow them to maintain this habit. However, due to the costs involved in acquiring this type of diet, people find themselves in need to prioritize the quantity of food over quality [36], this behavior is called nutrition resilience, which is highly relevant for the development of carious lesions and periodontal disease, since nutrition plays a key role in etiology. However, the limitation they may have due to the language barrier may at some point be an impediment to accessing health services. Chan B et al. mentioned that the migrant population often resorts to multiple strategies to communicate when they need a health service. These strategies include the use of technology such as translation websites, an acquaintance who helps them with interpretation, and finally, the self-confidence they have in overcoming this barrier encourages them to have short and simplified interviews with health personnel [37].

Of all the studies included in this work, only two studies focused on a review of the oral mucosa, reporting that in migrants where the habit of smoking was deeply rooted with 90.2% of their population, the most common premalignant lesion was leukoplakia (14.7%), followed by fibrous lesions [29]. Another study similarly reported that most frequent lesions presented by the migrant population were fibrous lesions, followed by migratory glossitis [8]. It is already well established that tobacco use in its different forms is a causal factor of mucosal lesions with malignant potential, so it is important to maintain close surveillance to make the correct early diagnosis of these lesions; Juárez SP et al., in their study, indicate that the migrant population in North America may show an increased risk of moderate alcohol and drug use, as well as an increase in physical inactivity [38].

One of the weaknesses of this study is that the information presented about oral lesions among the migrant population is taken from studies where self-diagnosis is carried out by the population, The use of self-reported data in oral health studies may introduce social desirability bias, as participants might respond in a manner they believe is more socially acceptable rather than providing accurate information. This tendency can lead to an overestimation of positive oral health behaviors and conditions, thereby affecting the validity of the findings and potentially underrepresenting the true prevalence of oral health issues within the studied population. Ia Another limitation of the systematic review is that the information is very heterogeneous, which complicates its analysis and understanding. Therefore, it is necessary to conduct studies where the presence of oral conditions and lesions is assessed by an oral health professional. In addition, only studies within a limited period (2016–2025) were selected, which does not represent the totality of what has been published on the subject.

Conclusions

The migrant population is characterized by limited access to health services, coupled with their limited economic resources, which makes them susceptible to developing oral lesions. This is corroborated by the high incidence of dental caries and bleeding gums.

Although the evidence suggests that migrants make an effort to maintain the custom of having a diet as natural as possible, this may be diminished by the economic factor or by a process of resilience, so we consider it is of vital importance to carry out two actions with this population: (1) identify the real state of oral health, carried out by professionals in dentistry and (2) carry out, within the possibilities, oral health campaigns that allow the early identification of lesions that could develop into more serious issues. All above leads us to require studies to analyze the oral health status of diverse migrant populations around the world.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Abbreviations

HIV

Human immunodeficiency virus

DMFS

Decayed, missing, and filled permanent teeth or surfaces

DMFT

Decayed, Missing, and Filled Teeth

Author contributions

Conceptualization, Garcia-Calderon AG, and Cuevas-Gonzalez MV; Methodology, Cuevas-Gonzalez JC, Espinosa-Cristobal, and Reyes-Lopez SY; Validation, Tovar-Carrillo KL; Formal analysis, Saucedo-Acuña RA, Zambrano-Galván G. and Osornio-Rojas JL; Investigation, Fornelli-Martin Del Campo LF; Data curation, Maya-Garcia IA.

Funding

None.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and informed consent statement

Not applicable.

Institutional review board statement

Not applicable.

Competing interests

The authors declare no competing interests.