The authors have declared that no competing interests exist.
Gingivitis and poor oral hygiene status are the most prevalent oral diseases among primary school students. Poor oral hygiene status, gingivitis and socio-demographic determinants have been shown to be associated with periodontal diseases. There is limited information on the gingivitis and oral hygiene status among Iranian children. In the present study, the status of gingivitis, oral hygiene status, and their association with socio-demographic determinants among schoolchildren aged 7–12 years old in Hamadan were investigated.
In this cross-sectional study, 988 primary school students aged 7–12 years old were selected. The oral hygiene status was measured through Simplified Oral Hygiene Index (OHI-S) and Community Periodontal Index (CPI) was used to evaluate gingival bleeding and calculus. CPI was measured using a standardized protocol to investigate gum bleeding and calculus. The oral hygiene was classified as good, fair or poor based on calculus and debris measurements. Age, gender, educational level, occupation and residence district of parents, dental pain experience in the last year and whether parents supervised their children while brushing were assessed by the questionnaires. The collected data were analyzed using descriptive statistics and logistic regression analysis.
The oral hygiene status was good in 644 students (65.20%), fair in 341 (34.50%) and poor in three (0.30%). Moreover, the results of CPI depicted that 639 students (64.07%) had healthy periodontium, 320 (32.40%) had periodontal bleeding and 29 (2.9%) were with calculus.
Higher percentage of the boys in the age group of 12 years old had periodontal bleeding and fewer good oral hygiene. The results of CPI and OHI-S scores depicted that more than half of the primary school students had healthy gums and periodontium (64.1%) and good oral hygiene status (65.2%).
There were significant statistical associations between age and residence district with calculus measured by the CPI, also between gender, age, residence district, and mother's occupation with the gingival bleeding measured by the CPI. Furthermore, age and mother's occupation were significantly associated with OHI-S index.
In general, the periodontal health status is poorer in students attending suburban schools compared to those in urban schools in Hamadan. Since there are significant associations between gender, school districts and mother’s occupation with oral hygiene index among schoolchildren in primary schools, considering them in schools’ oral health program design might be useful.
Oral diseases are important since they can lead to tooth loss and affect the general health and wellbeing of children through influencing their diet, speech and deteriorating already present chronic diseases such as diabetes and heart disease [
It has been demonstrated that occasional tooth brushing and high consumption of sugary foods are associated with increased severity and extent of periodontal inflammation[
Since the treatment of periodontal disease is complicated and costly, and specialized services are not available in all parts of the country [
The Ethics Committee of Hamadan University of Medical Sciences approved this study (IR.UMSHA.REC.1394.473). The parents signed a written informed consent in which they were explained about the study objectives, the risks and benefits and the voluntary nature of participation in the study. Verbal consent and permission were also obtained from all children aged 7 to 12 years. All de-identified data were collected from the study participants. No direct benefits or rewards were paid to participants for their participation in this study.
The current cross-sectional study was conducted on primary school students aged 7 to 12 years old in Hamadan, western Iran, between March and May 2016. Only children whose parents/legal guardians declared their informed consent participated in the study.
The sampling method was multistage cluster sampling (at three steps) aimed at selecting eligible participants [
The sample size was calculated based on this formula (z21-α/2) σ2/d2 and the standard deviation based on previous studies was inserted as 2.74[
The study inclusion criteria were the age range of 7–12 years old, no history of systemic diseases, and not being under orthodontic treatment at the time of study. The dental indices were measured by using Community Periodontal Index (CPI) and Simplified Oral Hygiene Index (OHI-S)[
All the dental examinations were performed by a postgraduate dental student experienced in the use of WHO criteria. He was calibrated by dental public health faculty at the School of Dentistry, Hamadan University of Medical Sciences. He had clinically examined more than 500 patients mainly children regarding their dental and oral health in the School of Dentistry, Hamadan University of Medical Sciences. The Kappa agreement between the examiner and dental public health faculty were 0.91 and 0.86 for CPI and OHI-S, respectively.
These examinations were conducted according to infection control standards [
A disposable dental blunt-ended explorer and mirror were used for each examination. The obtained information was recorded in the information form designed according to the WHO standard chart [
The oral hygiene status was determined via the Simplified Oral Hygiene Index (OHI-S) developed by Greene and Vermillion, consisting of two components of debris and calculus, each with a possible score ranges of zero to three [
The statistical analysis was performed using SPSS version 16.0 software. The OHI-S score varies between 0 and 6; 0–1.2 (good oral hygiene status), 1.3–3 (fair oral hygiene status) and 3.1–6 (poor oral hygiene status) [
The descriptive statistics (mean, standard deviation, frequency and percentage) were calculated for all demographic variables and indicators. The logistic regression analysis was performed to examine the associations between preset independent variables (age, gender, parental occupation and education, residence district, dental pain experience in the last year as well as parental supervision while tooth brushing) with outcome variables (OHI-S and CPI indices). The 95% confidence interval (CI) and odds ratio were calculated and the significance level was considered P<0.05 in all statistical tests.
Based on previous research, the demographic profiles, including age, gender, residence district, dental pain experience, parental education and occupation, and parent supervision, could predict CPI and OHI-S [
Age, gender, residence district, dental pain experience, parental education and occupation, and parental supervision were the independent/predicting variables in the Multiple and multinomial logistic regression analyses. As regards, the number of cases with poor oral hygiene was low to run the logistic regression for the OHI-S index. So, the oral hygiene status was further recoded to good oral hygiene and fair/poor oral hygiene. The fair/poor oral hygiene was calculated through combining fair and poor oral hygiene (fair oral hygiene+poor oral hygiene = fair/poor oral hygiene).
Multiple logistic regression analysis was executed to test the associations of preset independent/predicting variables with the outcome variable of oral hygiene status based on the calculated OHI-S. Multinomial logistic regression analysis was executed to test the associations of preset independent/predicting variables with the outcome variable of CPI including three layers of healthy, bleeding and calculus. CPI reference category is zero or healthy, the exponential estimates were expressed as odds ratios (OR) with 95% confidence intervals (CI).
The oral hygiene status was good in 644 students (65.2%), fair in 341 (34.5%) and poor in three (0.3%). Moreover, the results of CPI showed that 639 students (64.1%) had healthy periodontium, 320 (32.4%) periodontal bleeding and 29 (2.9%) were with calculus; so that 60.2% of boys and 69.3% of girls had healthy periodontium and 63.4% of boys and 67% of girls had good oral hygiene (
Variables | Categories | N | OHI-S |
CPI |
||||
---|---|---|---|---|---|---|---|---|
Good |
Fair |
Poor |
Healthy |
Bleeding |
Calculus N (%) | |||
gender | Boys | 503 | 319(63.4) | 183(36.4) | 1(0.2) | 303(60.2) | 184(36.6) | 16(3.2) |
Girls | 485 | 325(67) | 158(32.6) | 2(0.4) | 336(69.3) | 136(28) | 13(2.7) | |
Age(year) | 7 | 153 | 129(84.3) | 24(15.7) | 00(0.0) | 132(86.3) | 19(12.4) | 2(1.3) |
8 | 150 | 121(80.7) | 29(19.3) | 00(0.0) | 121(80.7) | 27(18) | 2(1.3) | |
9 | 158 | 102(64.6) | 56(35.4) | 00(0.0) | 105(66.5) | 49(31) | 4(2.5) | |
10 | 155 | 85(54.8) | 70(45.2) | 00(0.0) | 87(56.1) | 64(41.3) | 4(2.6) | |
11 | 178 | 103(57.9) | 72(40.4) | 3(1.7) | 101(56.7) | 72(40.4) | 12(6.2) | |
12 | 194 | 104(53.6) | 90(46.4) | 00(0.0) | 93(47.9) | 89(45.9) | 12(6.2) | |
Residence district | Urban | 571 | 370(64.8) | 201(35.2) | 00(0.0) | 380(66.5) | 165(28.9) | 26(4.6) |
Suburban | 417 | 274(65.7) | 140(33.6) | 3(0.7) | 259(62.1) | 155(37.2) | 3(0.7) | |
Dental pain experience | Never | 284 | 185(65.1) | 97(34.2) | 2(0.7) | 178(62.7) | 91(32) | 15(5.3) |
Seldom | 432 | 267(61.8) | 164(38) | 1(0.2) | 265(61.3) | 156(36.1) | 11(2.5) | |
Often | 272 | 192(70.6) | 80(29.4) | 00(0.0) | 196(72.1) | 73(26.8) | 3(1.1) | |
Father’s Education | ≤Primary | 58 | 38(65.5) | 19(32.8) | 1(1.7) | 41(70.7) | 16(27.6) | 1(1.7) |
High School | 790 | 517(65.4) | 271(34.3) | 2(0.3) | 512(64.8) | 258(32.7) | 20(2.5) | |
>High School | 140 | 89(63.6) | 51(36.4) | 00(0.0) | 86(61.4) | 46(32.9) | 8(5.7) | |
Mother’s Education | ≤Primary | 59 | 36(61.00) | 22(37.30) | 1(1.70) | 38(64.40) | 20(33.90) | 1(1.70) |
High School | 827 | 546(66.00) | 279(33.70) | 2(0.20) | 539(65.20) | 267(32.30) | 21(2.50) | |
>High School | 102 | 62(60.80) | 40(39.20) | 00(0.00) | 62(60.80) | 33(32.40) | 7(6.90) | |
Father’s occupation | Labor worker | 129 | 82(63.6) | 47(36.4) | 00(0.0) | 77(59.7) | 47(36.4) | 5(3.9) |
Government employee | 631 | 138(61.9) | 85(38.1) | 00(0.0) | 144(64.6) | 72(32.3) | 7(3.1) | |
Self-employed | 223 | 420(66.6) | 208(33) | 3(0.5) | 415(65.8) | 199(31.5) | 17(2.7) | |
Not employed | 5 | 4(80) | 1(20) | 00(0.0) | 3(60) | 2(40) | 00(0.0) | |
Mother’s occupation | Labor worker | 8 | 5(62.5) | 3(37.5) | 00(0.0) | 4(50) | 4(50) | 00(0.0) |
Government employee | 101 | 27(45.8) | 32(54.2) | 00(0.0) | 30(50.8) | 25(42.4) | 4(6.8) | |
Self-employed | 59 | 73(72.3) | 28(27.7) | 00(0.0) | 75(74.3) | 24(23.8) | 2(2) | |
Not employed | 820 | 539(65.7) | 278(33.9) | 3(0.4) | 530(64.6) | 267(32.60) | 23(2.8) | |
Parental supervision on oral hygiene | Yes | 350 | 213(60.9) | 135(38.6) | 3(0.4) | 210(60) | 128(36.6) | 12(3.4) |
No | 638 | 431(67.6) | 206(32.3) | 1(0.2) | 429(67.2) | 192(30.1) | 17(2.7) |
aOHI-S denoted that present data for Simplified Oral Hygiene Index.
bCPI denoted that present data for Community Periodontal Index
Higher percentage of the boys in the age group of 12 years old had periodontal bleeding (52.9%) and fewer had good oral hygiene (51%) (Not presented in the tables).
Among the demographic factors, age (p = 0.002) and residence district (p = 0.01) were significantly associated with calculus measured by the CPI. For each year of age increase, the chance of developing calculus increased by 1.53 times. Among the independent variables, gender (p = 0.003), age (p<0.001), residence district (p = 0.01) and mother's occupation (p = 0.02) were significantly associated with gingival bleeding measured by the CPI (
Predictor Variables | Bleeding | Calculus | ||
---|---|---|---|---|
Adjusted OR |
Adjusted OR |
|||
1.44(1.31–1.59) | <0.001 | 1.53(1.17–2.02) | 0.002 | |
Boys | 1.54 (1.16–2.06) | 0.003 | 1.43(0.65–3.11) | 0.36 |
Girls(Reference category) | ||||
Urban | 0.69 (0.51–0.93) | 0.01 | 5.21(1.49–18.18) | 0.01 |
Suburban(Reference category) | ||||
Never | 0.97 (0.64–1.45) | 0.88 | 2.97(0.79–11.18) | 0.10 |
Seldom | 1.12(0.78–1.61) | 0.53 | 1.58(0.41–6.11) | 0.50 |
Often(Reference category) | ||||
≤Primary | 0.52 (0.19–1.42) | 0.20 | 0.48(0.02–8.25) | 0.61 |
High School | 0.88(0.51–1.51) | 0.65 | 0.73(0.22–2.40) | 0.60 |
>High School(Reference category) | ||||
≤Primary | 1.43(0.51–4.01) | 0.48 | 0.60(0.03–11.04) | 0.73 |
High School | 1.05(0.55–1.99) | 0.87 | 0.59(0.15–2.20) | 0.43 |
>High School(Reference category) | ||||
Labor worker | 1.50(0.89–2.55) | 0.12 | 3.63(0.91–14.44) | 0.06 |
Self-employed | 1.13(0.78–1.64) | 0.50 | 1.63(0.59–4.46) | 0.34 |
Government employee(Reference category) | ||||
Not employed | 0.55(0.29–1.05) | 0.07 | 0.61(0.16–2.36) | 0.48 |
Self-employed | 0.40(0.18–0.86) | 0.02 | 0.42(0.06–2.81) | 0.37 |
Government employee(Reference category) | ||||
Yes | 0.85 (0.62–1.17) | 0.32 | 0.78(0.34–1.78) | 0.55 |
No(Reference category) |
CPI reference category is: healthy
CI, confidence interval; OR, odds ratio
aThe regression was adjusted for sex & age
Age (p<0.001) and mother's occupation (p = 0.008) were significantly associated with OHI-S index. For each year of age increase, the likelihood of developing poor and fair oral hygiene increased 1.36 times (p<0.001). The primary school children with mothers employed in the government were 2.27 more likely to have fair/poor oral hygiene than those with unemployed or self-employed mothers (
Predictor Variables | Adjusted OR |
|
---|---|---|
1.36(1.24–1.48) | <0.001 | |
Boys(Reference category) | ||
Girls | 0.85(0.64–1.11) | 0.24 |
Center (Reference category) | ||
Suburb | 0.96(0.71–1.28) | 0.79 |
Never (Reference category) | ||
Seldom | 0.86(0.63–1.18) | 0.36 |
Often | 1.28(0.89–1.83) | 0.17 |
≤Primary (Reference category) | ||
High School | 1.18(0.53–2.58) | 0.67 |
>High School | 1.00(0.39–2.55) | 0.99 |
≤Primary (Reference category) | ||
High School | 0.66(0.31–1.41) | 0.29 |
>High School | 0.66(0.25–1.77) | 0.41 |
Labor worker (Reference category) | ||
Self-employed | 0.91(0.59–1.39) | 0.66 |
Government employee | 0.97(0.58–1.60) | 0.91 |
Not employed (Reference category) | ||
Self-employed | 0.81(0.52–1.29) | 0.39 |
Government employee | 2.27(1.23–4.17) | 0.008 |
Yes (Reference category) | ||
No | 1.12(0.83–1.52) | 0.43 |
CI, confidence interval; OR, odds ratio
aThe regression was adjusted for sex & age
The results of this study showed that the highest prevalence of periodontal problem was observed in the boys aged 12 years of age since 52.9% had gingival bleeding according to CPI scores and the fair oral hygiene was 49%. By comparing the present study’s results with other studies, it was found that the gingival bleeding component of CPI in this study was 1.42 times higher in 7 year old students and also 3.61 times higher in the 12 years old age group when compared with the same age groups in the 2012 national survey results for the Hamadan population [
The results of this study also showed that the mean OHI-S scores of students was approximately similar to OHI-S scores reported of students in India and other studies in Iran[
Dental care should be started according to the recommendation of the American Academy of Pediatric Dental Association from the infant age[
Like most studies, the present study’s findings showed that the prevalence of teeth with periodontal bleeding, presence of calculus and the oral hygiene index were related to age, so that younger children had a better oral hygiene status and periodontal health[
The results of CPI depicted that gender is associated with the gingival bleeding score. The incidence of bleeding in boys was 1.54 times more likely than that in girls. Al-Haddad et al.[
Similar to some studies, our findings show that the place of residence is associated with the number of sextants with periodontal bleeding and calculus[
The results of this study showed that mother's occupation is related to the number of sextants with periodontal bleeding and oral hygiene status. Qajari et al., Zurriaga et al., and Sim et al., also reported the same results[
Many studies, including our research have shown that parental education and fathers’ occupation do not predict the gingival bleeding, calculus and oral hygiene in their children[
This study had some limitations. First, the cross-sectional nature of the study does not show causal relationship between the students’ gingivitis, oral hygiene status and their socio-demographic characteristics. However, cross-sectional studies are important in identifying risk factors, which could be used for maintaining population health and conducting future cohort or longitudinal assessments based on the identified risk factors.
In this study, the CPI was used to investigate the prevalence and severity of periodontal disease which has many criticisms that are based on the progressive definition of periodontal disease; so that a tooth with a pocket present must also have calculus and bleeding[
The statistical results in this study could also be affected by socially acceptable responses about parent's occupation, educational level and positive supervision on primary school aged children’s tooth brushing. This might suggest that socioeconomic characteristics of the parents could not predict the gingivitis and the oral hygiene status in primary school students[
One of the strengths of this study is the large sample size of 7–12 years old primary school students in Hamadan for assessing the oral hygiene status and periodontal health compared to similar studies[
In general, the study results demonstrated that more than 60% of the Hamadan primary school students had healthy gingiva and periodontium (64.1%) and their oral hygiene status was good (65.2%). Age, gender, residence district and mother’s occupation were significantly associated with bleeding and calculus components of the CPI. Furthermore, age and mother's occupation were significantly associated with the oral hygiene index. More children from urban areas had healthy periodontium than those living in suburban areas and boys compared to girls. The current results indicate that oral hygiene is an important public health concern among 7–12 years old students in Hamadan primary schools. Therefore, an active and effective preventive program is essential for improving pediatric oral hygiene status, especially for children attending to suburban schools.
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The authors are grateful to the department of Educational in Hamadan, Schools administrators and teachers for their sincere cooperation with the authors.