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 Table of Contents  
Year : 2021  |  Volume : 2  |  Issue : 2  |  Page : 49-55

A comparative study of oral health status of outpatients with mental disorders and healthy controls in a Nigerian tertiary hospital

1 Department of Preventive and Community Dentistry, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Osun State, Nigeria
2 Department of Mental Health, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
3 Department of Preventive and Community Dentistry, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
4 Department of Preventive and Community Dentistry, Aminu Kano University Teaching Hospital, Kano, Kano State, Nigeria

Date of Submission11-Apr-2021
Date of Decision18-May-2021
Date of Acceptance20-May-2021
Date of Web Publication24-Jun-2021

Correspondence Address:
McKing Izeiza Amedari
Department of Preventive and Community Dentistry, Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Osun State
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jpcdoh.jpcdoh_15_21

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Objective: The objective of this study was to determine and compare the oral health status of outpatients with mental disorders (OPMDs) and healthy controls (HCs) in a Nigerian tertiary hospital. Methodology: A comparative cross-sectional study among 140 OPMDs was consecutively recruited from the Mental Health Clinic of a Nigerian tertiary teaching hospital. Furthermore, 140 age- and sex-matched HCs screened using the 12-item General Health Questionnaire were recruited from the general outpatient clinic. Oral health status was assessed using the Decayed, Missing, and Filled Teeth (DMFT) index, the community periodontal index modified (CPI modified), the Oral Hygiene Index-Simplified (OHI-S), and the gingival index (GI). Bivariate analyses were carried out to make comparisons between the two groups, and the level of significance was set at P < 0.05. Results: A total of 280 participants were recruited. This comprised 68 male participants and 72 female participants in each group. The mean DMFT in the OPMD group was 0.50 (±1.09) and 0.17 (0.645) for the HC group. The prevalence of dental caries was 24.3% in the OPMD group and 10% in the HC group. The mean OHI-S score was 2.68 (±0.97) and 2.38 (±0.98) and GI score was 1.09 (±0.46) and 0.87 (±0.87), while clinical attachment loss was seen in 48.5% and 32.8% for the OPMD and HC groups, respectively. Conclusion: The prevalence of common oral diseases in OPMD was higher compared to HC, thus the study provides evidence on the poor oral health of OPMD. Furthermore, there is a need to incorporate preventive dental education into the management of OPMD.

Keywords: Clinical attachment level, dental caries, mental disorders, oral health status

How to cite this article:
Amedari MI, Akinsulore A, Ogunbodede EO, Jeboda SO. A comparative study of oral health status of outpatients with mental disorders and healthy controls in a Nigerian tertiary hospital. J Prim Care Dent Oral Health 2021;2:49-55

How to cite this URL:
Amedari MI, Akinsulore A, Ogunbodede EO, Jeboda SO. A comparative study of oral health status of outpatients with mental disorders and healthy controls in a Nigerian tertiary hospital. J Prim Care Dent Oral Health [serial online] 2021 [cited 2021 Oct 24];2:49-55. Available from: http://www.jpcdoh.org/text.asp?2021/2/2/49/319194

  Introduction Top

Oral health is linked with general well-being because it influences the nature of the food eaten, verbal communication, confidence, and emotional state which is part of our mental health.[1],[2] Oral health disorders are a global public health problem with concern over their increasing prevalence in the low- and middle-income countries (LMICs).[3] Many of these oral health disorders are linked with chronic systemic conditions including cardiovascular diseases, respiratory diseases as well as mental disorders.[3] A bidirectional relationship has been described between oral health and mental health.[4] On the one hand, it is recognized that about 50% of all dental patients experience some anxiety about visiting a dentist, and in some cases, this can lead to a dental phobia which has been identified as a specific form of phobia.[5],[6],[7]

Dental caries and periodontal disease are the two major oral health disorders that have a major impact on oral health.[6] In recording the state of the hard and soft tissue of the oral cavities of a group of individuals, the Decayed, Missing, and Filled Teeth (DMFT) index and the Community Periodontal Index (CPI) are commonly utilized for survey while other relevant tools include the Oral Hygiene Index-Simplified (OHI-S) and the Gingival Index (GI).[8] Poor oral health status has been reported among outpatients with mental disorders (OPMDs) in developed countries, with mean DMFT scores of 10.5 (±10.2) and 41% having poor oral hygiene reported in a Swedish study.[9] These measures were worse as reported in Taiwan among inpatients with mental disorders who had a mean DMFT value of 14.9 (±8.8) and 45.9% prevalence of periodontal pockets.[10] However, lower mean DMFT values have been reported in LMICs such as India 2.10 (±1.7),[11] Ethiopia 1.92 (±2.12),[12] and Nigeria 2.3 (±2.28).[13]

Patients with Mental Disorders (PMDs) represent a vulnerable group who are often stigmatized, neglected, and ostracized by the community and their families.[4] Although their physical health has gained attention,[14] there has been less focus on their oral health which has been reported to be an important predictor of quality of life.[15] There is also limited evidence on the oral health status of PMD in a LMIC such as Nigeria. The previous study focused on determining the dental status of PMD without including a comparative group. The aim of this study was therefore to determine the oral health status of OPMDs attending a mental health outpatient clinic and compare the results with an apparently healthy control group.

  Methodology Top

Study design

This study was a cross-sectional comparative design that described the oral health status of patients with and without mental health disorders. The study consisted of two groups. The study group comprised adults aged between 18 years and 70 years attending the mental health outpatient clinic with a diagnosis of a mental disorder of at least 3 months by a consultant psychiatrist (bipolar disorders, schizophrenia, substance use disorder, or anxiety disorder). The healthy group (HC) consisted of age- and sex-matched participants from the general outpatients' department who were screened using the 12-item General Health Questionnaire[16] and found to be apparently without a mental health disorder.

Ethical clearance

Ethical clearance for the conduct of this research was obtained from the Research and Ethics Committee of the Obafemi Awolowo University Teaching Hospitals Complex. Protocol number ERC 2017/07/08 was assigned to the study. Informed consent was obtained from all participants in the study. Based on the physical and verbal cues of the PMDs, a guardian was required to sign when the participant was incapable of doing so.

Study participants

Exclusion criteria

  1. Patients with comorbidities including other noncommunicable diseases
  2. Patients with other chronic oral diseases like oral cancers
  3. Patients with severe crowding or anatomical variations in dentition
  4. Patients who had received dental prophylaxis in the past 3 months
  5. Pregnant women or lactating mothers.

Sample size

The sample size was mathematically determined using the formula for estimating sample size when comparing two independent groups (2 [Zα+Zβ]2 × P [1-P]/[P0-P1]2).[17] The standard normal deviate, Zα corresponding to 95% confidence interval, was 1.96. The standard normal deviate, Zβ, which represents the power (at 80%), of obtaining a difference was 0.84. The prevalence of gingival inflammation among patients with mental health disorder according to Adeniyi et al.[13] was 96.2%, and the estimated difference between the two groups was set at 10%. A total sample size of 280 was reached for the two groups after the inclusion of a 10% attrition factor.


Information was obtained through a structured and validated questionnaire adapted from the WHO Oral Health Surveys: Basic Methods[8] standard forms on oral assessment and adjusted to suit the study. This was followed by a brief intraoral examination using the DMFT, CPI-modified, OHI-S, and the GI.[8]

The basis for the DMFT calculations was 32 teeth, all permanent teeth including the third molar. The various components (decayed, D, missing M, filled F) were totaled to give the DMFT score. Each component was assigned a score of 1, thus the lowest DMFT score could be zero and the highest score 32.

The CPI utilized two indicators in assessing periodontal status: the presence or absence of gingival bleeding and the presence or absence of shallow periodontal and deep periodontal pockets. All teeth present in the mouth were examined. Information on the loss of attachment gave an estimate of the lifetime accumulated destruction of the periodontal attachment. Using the cementoenamel junction as a landmark, codes for the index represented:

  • Code 0: Loss of attachment of 0–3 mm
  • Code 1: Attachment loss of 4–5 mm
  • Code 2: Attachment loss of 6–8 mm
  • Code 3: Attachment loss between 9 and 11 mm
  • Code 4: Attachment loss between 12 mm or more.

The OHI-S is a composite index that scored debris and calculus deposition on the index tooth surface. The index teeth were 16, 11, 26, 31, 36, and 46. This was utilized as a main assessment of oral hygiene. OHI-S values ranged from 0 to 6 and were interpreted as good (0–1.2), fair (1.3–3.0), and poor (3.1–6.0).

The GI was scored based on a 0–3 scale that combined an assessment of tissue color and form with bleeding on stimulation. Index teeth assessed were 16, 12, 24, 32, 36, and 44. The index was scored as follows: <0.1= Excellent, 0.1-1.0=good (mild or no inflammation), 1.1-2.0=fair (moderate inflammation), 2.1-3.0=poor (severe inflammation).

Data analysis

All data were summarized using frequencies and percentages for categorical data and means and standard deviations (SDs) for continuous variables. Data were checked with Kolmogorov–Smirnov test for normality. Chi-square test was subsequently used to make comparisons for the categorical data between the two groups and the Mann–Whitney U test was used to compare the continuous variables between the two groups. The level of significance was set at P < 0.05 for statistical analysis.

  Results Top

A total of 280 outpatients participated in the study. This consisted of 140 consecutive outpatients with mental health disorders and a comparison group consisting of 140 out-patients. These patients were screened with the GHQ from a pool of 172 general outpatients and apparently without a mental disorder. [Table 1] and [Table 2] highlight the sociodemographic characteristics and the clinical characteristics of the OPMDs, respectively.
Table 1: Sociodemographic characteristics of the participants

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Table 2: Clinical characteristics of patients with mental disorders

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The mean (±SD) OHI-S score for the study group was 2.68 (±0.97) while that for the control group was 2.38 (±0.98), and this difference was statistically significant (P = 0.022). The mean (±SD) GI score for the study group was 1.09 (±0.46), while that for the control group was 0.87 (±0.35). The difference was also statistically significant with P < 0.001.

The CPI modified index provided information on the mean number of teeth with gingival bleeding and periodontal pockets as well as the clinical attachment level (CAL). The mean (±SD) number of teeth with gingival bleeding in the study group was 2.96 (±2.97) which was significantly higher than 0.46 (±1.02) seen in the control group (P < 0.001). Similarly, the mean (±SD) number of teeth with periodontal pockets in the study group was 1.26 (±1.88) which was higher than the 0.42 (±1.06) recorded in the control group, and the difference was statistically significant (P < 0.001). The prevalence of gingival bleeding and periodontal pockets (shallow and deep) was 67.9% and 38.5% in the study group and was higher than the values seen in the control group. These differences were statistically significant (P < 0.001 and P < 0.001, respectively). The index also provided information on the CAL. There was no statistically significant difference between the groups, however, the study group had a higher level of clinical attachment loss [Table 3].
Table 3: Oral hygiene, Gingival health and Clinical Attachment levels of Out-patients with and without mental disorders

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Almost a quarter (24.3%) of the participants in the study group had dental caries experience compared to the control group (10%), and this difference was statistically significant (P = 0.002). The number of decayed teeth ranged from 0 to 5 among the participants in the study group whereas the maximum number of decayed teeth in the control group was 1 [Table 4]. The OPMDs had higher DMFT scores than the control group, and the patients with schizophrenia and bipolar disorder were significantly higher [Table 5].
Table 4: Dental caries experience of outpatients with and without mental disorders

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Table 5: A comparison of the mean Decayed, Missing, and Filled Teeth values among the four groups of mental disorders with the mean Decayed, Missing, and Filled Teeth of control group

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  Discussion Top

A majority of the participants in the study group were between the age groups of 20–39 years and few had attained a postsecondary level of education compared with the control group. This is consistent with other findings about PMD[7] and also attributable to the early onset of mental health problems and limited family and community support in these persons, as corroborated by Halpern-Manners et al.[18] in a study on the relationship between education and mental health.

Typical antipsychotics such as haloperidol were the most frequently prescribed medications for PMDs as documented among 42.4% of them. This is a far cry from what was reported in a study by Teng et al.[10] in which only 16.5% received typical antipsychotics and over 80% were on atypical antipsychotics. Prescribing either the typical antipsychotics or atypical antipsychotics has dental implications, which the mental health physician should be aware of while also considering the prescription effectiveness in treatment outcomes for each patient.[19] Grinshpoon reported better dental health in patients treated with atypical antipsychotics compared to typical antipsychotics, and it was suggested that atypical antipsychotics are less likely to give rise to the apathy and low motivation associated with poor dental health-seeking behavior in patients on typical antipsychotic therapy.[19] A considerable proportion (35%) of the participants in this study presented with grimacing, oral dyskinesia, collectively referred to as extrapyramidal symptoms and being the most common side effects of typical antipsychotics. Because these symptoms limit oral hygiene practice, extrapyramidal symptoms in PMD should be considered as a major determinant of oral health status among persons with mental health disorders.

OPMD as well as the HC group had a fair rating in their oral hygiene using the OHIS. However, there was a significant difference in terms of their mean scores (2.68 [±0.97] and 2.38 [±0.98)] P = 0.022). This difference can be explained by the literature report of perceived apathy towards oral health care in addition to the side effects of psychotropic medication which promotes plaque and calculus formation.[6],[20],[21] This finding is similar to what was reported by Adeniyi et al.[13] who stated a mean OHI-S score of 2.70 (±1.20) among OPMDs, a study also conducted in the southwestern region of Nigeria where our study was also conducted.

All the participants in both groups had varying degrees of gingival inflammation, although more participants in the study group had moderate and severe degrees of inflammation than in the control group. The difference is more explicitly illustrated when the CPI modified record of gingival bleeding is considered. An average of almost three teeth in each participant in the study group were associated with gingival bleeding compared to an average of <1 tooth in the control group. This is as a result of the long-term neglect of the oral health and a lack of a good oral hygiene practice which predisposes to the debris accumulation and the subsequent occurrence of gingival inflammation in this cohort. The index indicated a higher prevalence of periodontal pockets in patients with mental health disorders (38.6%) compared to the outpatients without mental health disorders (13.5%). Because the CPI modified index requires examination of all teeth in the mouth, it offers a more comprehensive means of recording and surveillance systems for periodontal pockets compared to the CPI of treatment needs more commonly used in oral health surveys.[22] Apart from the presence of periodontal pockets, the level of clinical attachment offers more information on the lifetime accumulated periodontal destruction. This study revealed that 48.5% of the participants in the study group had varying degrees of clinical attachment loss compared to 32.8% seen in the control group. Such tissue destruction is an indication of a chronic oral health condition. In this case, the higher periodontal destruction in the study group is attributable to the background chronicity of a mental disorder leading to this adverse measurable oral health outcome.[23]

Our study reported higher mean DMFT scores in OPMD compared to the HC group, and the difference was statistically significant. However, our values were quite low compared with other studies on PMD.[11],[12],[13] This study was a hospital-based study, and the finding of a low mean DMFT in the study and control groups may be a reflection of the low levels of dental caries also seen in the general population. Although < 10% of the Nigerian population have access to tap water making water fluoridation (a public health preventive strategy for dental caries) difficult to achieve,[24] widespread use of fluoridated toothpaste (reported by the participants in this study) may have contributed to an increased resistance of the tooth against dental caries.[25] The low DMFT is corroborated by a similar study which was community based among special needs children and teenagers conducted in Ile-Ife and reported a mean DMFT of 0.2 (±0.60).[26] However, these studies are in agreement concerning the estimated mean decayed teeth which accounted for the highest component of the DMFT in both studies.

Notably, participants in the study group with schizophrenia (0.53 ± 1.10) and bipolar disorders (0.63 ± 1.42) were the two groups of mental disorders found to have mean (±SD) DMFT values significantly higher than the control group [Table 4]. Alhaffar et al.[27] also reported these two disorders as having the highest mean DMFT scores among the groups of mental disorders considered in his study. However, there is still a paucity of information on the relationship between the diagnostic entity of the mental disorder and the DMFT scores.[27] Notably, these two groups of disorders also had the highest mean years of duration of illness 8.50 (±7.53) and 9.34 (±10.33) in this study, and this is consistent with studies that revealed a positive correlation between the duration of illness and higher DMFT scores,[28],[29] thus buttressing the plausibility of a chronic duration of the mental disorders being linked with poor oral health outcomes in this study.

The results presented in this study depict the poor oral health status among OPMD, and the implication is that there must be a renewed focus on the provision of oral health care to OPMD. Oral health promotion activities including education and better communication about oral health at the mental health clinic can be introduced in order to overcome the limitations around oral care for OPMD.[30] This study is, however, not without its limitations, and the findings of this study should be interpreted with caution since a probability sampling technique was not adopted. However, participants were selected based on a set of inclusion and exclusion criteria which improved the quality of the study and also promoted its external validity. Similarly, the matching of participants further improved the internal validity of the findings of the study. There was a preponderance of the subgroup of schizophrenia in the study group. The milder forms of mental disorders (including mild depression and anxiety disorders) are not commonly treated at the mental health clinic, hence fewer were available to be recruited in the study group within the time frame for the study.

  Conclusion Top

This study has provided evidence about the poor oral health status seen in persons with mental disorders. The prevalence of dental caries and clinical attachment loss was higher in outpatients with mental health disorders compared to general outpatients. The oral health status of PMDs deserves more attention, and the findings from this study strengthen the call for a need for integrated delivery of mental and dental health services in the management of PMDs. Mental health professionals, who are the primary caregivers, need to be alert to the oral health complaints of PMDs and make prompt referrals to the dental professionals when necessary. Furthermore, dental and mental health professionals need to build collaborations to facilitate the delivery of holistic health care to PMDs.


The authors acknowledge Dr. Tolu Ogunye for her technical support in assisting to help maximize the cooperation of the OPMDs.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


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