In the today’s modern dentistry, not only the impact of children’s oral and dental diseases in various aspects of life is given attention,but also the child's family and the Quality of Life (QoL) related to oral and dental health is reflected and evaluated [1, 2].Oral and dental diseases are common in children [3] that can give children an ugly appearance and affect their future performance and success [4]. In addition, these diseases also have a significant effect on family structure, including economic pressures, restrictions on the social life of family members, and reduced relationships with others [5].

The current epidemiology of dental caries in the world reflects a clear vision of basic risks regarding conditions, lifestyle and environmental factors. Statistics shows that about 60% to 90% of school children suffer from dental caries [6], and due to problems regarding oral and dental health, over 50 million hours is annually wasted at schools [7]. In addition, statistics shows that the prevalence and severity of dental caries in the past 20 years have significantly increased in developing countries [3]. Oral and dental health is currently known as one of the 11 slogans of the 21st century [8]. Reducing the dental caries index or the decay-missing-filled index for permanent teeth (DMFT) to less than one in 12-year-old youngsters had been among the goals of the World Health Organization (WHO) by the year 2010 [9]. The new goals of this organization in the year 2020 are focused on making use of experiences and evaluation of previous goals and emphasis on the importance of oral and dental health as an indispensable component of public health [10]. Since the year 1995 in Iran in line with the integration of healthcare activities in the healthcare network system of the country, the scheme of integration of oral and dental health and primary health care has been raised with the aim of promoting the oral and dental health of community members [11].

A review of previous studies conducted in the country shows that the decay-missing-filled index in Iranian children is much higher than the global average [3]. In a study carried out by Ajami and Ebrahimi in Mashhad in 2001, the mean of decay-missing-filled index for primary teeth (dmft) in children aged 6-7 years old was reported 4.72 ± 4.18 [12]. Also, in a study conducted by Mohebi et al. in 2007 on primary third-grade students in Gonabad, the mean of dmft and DMFT in male and female students were estimated 1.04 ± 0.22 and 3.86 ± 1.11, respectively [2]. However, a review of studies conducted in other countries shows that the mean of these indexes is much lower in other countries. In studies carried out by Vizzotto et al. [8] in 12-year-old Brazilian students, and Nuca et al. [13] in Romanian children aged 6-12 years old, the rate of these indexes has been reported less than 1. On the other hand, a review of Oral Health-Related Quality of Life (OHRQoL) studies also indicates that there are different questionnaires in the world for studying OHRQoL from the perspective of different people, such as parents, caregivers, and children in different age groups [14]. However, due to the limited number of studies conducted in our country [15], no new information is available about the oral and dental health status of children in primary schools of Torbat Heydariyeh. Also, due to little information on children’s OHRQoL in Iranian families, the authors decided to carry out a study aimed at determining the correlation between the oral and dental health status of primary school children and QoL of their families in Torbat Heydariyeh county.

The mean of mother’s age was 36.9±4.9 with the range of 36-41 years. The mean of the age of children was 11.5±0.5 years. The rest of the demographic and clinical information about mothers and children is shown in Tables 1 and 2. Table 3 shows the mean of dmft and DMFT according to gender in primary school children.

In this study, the mean of the FIS score was estimated 13±7.5 out of the maximum score (56). In a correlation matrix, the relationships between FIS and dmft index as well as DMFT was investigated using Person’s correlation tests. Results showed that there was no significant relationship between the FIS variable and children’s primary and permanent teeth decay index (dmft: r=0.06, p=0.337) (DMFT: r=0.08, p=0.185) (They have not been shown in the Table).

Poisson regression analyses were used to investigate the relationship between variables of dmft and DMFT indices as well as the FIS and demographic-clinical variables. At first by a series of univariate regression analyses significant demographic-clinical variables were found, and then significant variables were entered into the final models. The results of the Poisson regression analyses between children’s dmft and DMFT indices and demographic-clinical variables are shown in Table 4. The prevalence ratio (PR) of the dmft index has been increased 1.29 times more in children with bleeding gums. However, in mothers who visited a dentist over the past 8 months, a protective effect was seen. This means that the PR of the dmft index was 19% less common in children of these mothers. In addition, Table 4 shows a protective effect between the DMFT index of children and a number of demographic-clinical variables. This means that children using dental floss (27%), mothers visiting dentists over the past eight months (19%), and finally, female children compared with the males (39%) showed a lower PR of the DMFT index.

Results of the multiple linear regression analysis between the FI and demographic-clinical variables are shown in Table 5. Significant demographic-clinical variables were entered into the final model, following a series of univariate regression analyses. There is a significant reverse relationship only between the FIS and mothers visiting dentists over the past 8 months (β=-0.13, p=0.045). This means that mothers who visited a dentist over the past 8 months reported a lower FIS.

This study was aimed at determining the correlation between the oral and dental health status of primary school children and families’ QoL in Torbat Heydariyeh City. Investigating families’ QoL in the present study showed that the FIS mean was 13±7.5 out of the total score of 57. In a study which was carried out by Goursand et al. [17] in 123 parents-caregivers of children between 11 and 14 years of age in Brazil, the mean of FIS was reported 6.97±7.81. In comparison, our study had a higher average and showed a greater impact of oral and dental problems of children on families and lower QoL of families in Torbat Heydariyeh. Unexpectedly, in this study, no relationship was found between the oral and dental health status of children and families’ QoL. While, in the studies of Nemati et al., in Babol, Iran and Alsumait et al., in the Kuwait Capital Region, the life quality of the children and their parents was strongly influenced the oral and dental health status of children [18, 19]. This inconsistency can be related to methodological differences (e.g. the number of samples, the type of questionnaires, and the method of data gathering) in the present study.

With respect to the results of oral-dental health examinations in our study and observation of moderate intensity of children’s primary teeth decay and low permanent teeth decay, it may be explained that the intensity of tooth decay in children has not affected their families. It seems that Iranian families are more responsiveness to acute and severe oral and dental problems of children. This result is consistent with the findings of Mazaheri et al. [16]. However, in a study by Nilchian et al. [15] in the city of Amol, Iran a significant relationship was found only between the dmft and the FIS. In addition, several studies have shown that oral and dental problems of children can negatively affect the lives of children and parents [20, 21]. Also, Bönecker et al, reported that dental caries could cause functional, physical and aesthetic impairment at early ages, and caries lesions can compromise children’s QoL [22]. The results of study by Caglayan et al., showed that oral health-related QoL is correlated with the patient’s oral complaints. In addition to the patient’s oral health status, factors such as gender, education, and harmful habits may also influence on oral health-related QoL [23]. In the study by James et al., Mother’s sense of coherence was negatively associated with the child’s caries experience, which affected oral health related QoL of their children. In this context, improving a mother’s Sense of coherence can be considered as the key to better oral health and QoL [24]. The results study of Qiu et al., indicated that socioeconomic factors could influence on children’s oral health practices, which may be directly related to their caries [25].

Regarding the dmft index, the results of regression models showed that in children with bleeding gums, the PR of primary teeth decay has been higher. However, the prevalence rate of primary teeth decay in children whose mothers visited a dentist over the past eight months was lower. In addition, regarding the DMFT index, the results also showed a protective effect such that the possibility of permanent tooth decay was lower in children using dental floss or in children whose mothers visited a dentist over the past 8 months, and also in female students compared to the males. In addition, with mothers’ frequent visits to dentists over the past 8 months, the effect of oral and dental problems of children on families decreased and families’ QoL subsequently improved.

Application of the self-reported questionnaires proposes a possibility for recall bias. Also, mothers’ conditions during responding to the questionnaires could be influential in their responses.

In conclusion, although this study did not show a significant relationship between primary and permanent teeth decay in children and families’ quality of life, the findings showed that the health status of primary and permanent tooth of children in Torbat Heydariyeh is far away from the goals of the WHO. Therefore, there is still a long way to reach ideal goals. It is considerable for health policy makers, school nurses and the rest of the involved healthcare forces. They should mobilize resources and take measures, such as educational interventions in order to improve oral and dental health status of children at schools.