4. DISCUSSION
Leukemias constitute the vast majority of childhood HM, and the most common of these is ALL 9. In this study, the majority of the children with HM were ALL patients, which agrees with previous studies. Oral health can adversely affect the QoL of adults and children, and their families. 10The SOHI has been used to obtain information about the oral care habits and QoL of individuals varying in age, ethnicity, and sociocultural and health status11. In this study, the SOHI was higher in the HM group than the control group, despite similar sociocultural and economic conditions; the difference may have been related to treatment complications, such as mucositis, saliva volume and swallowing difficulties, along with poorer self-care in children with HM12, 13 .OHRQoL is an important public health issue with physical and psychological implications. OHRQoL differs among communities and ethnic groups, depending on the level of awareness of its importance and access to treatment14.
OHRQoL research has shown utility in studies of diverse populations, including oral cancer patients 15, sleep apnea patients 16, toddlers with early childhood caries17, and children with craniofacial anomalies18 .
Various scales, such as the ECOHIS19 and Child Perceptions Questionnaire20 , have been used to determine OHRQoL in children of various ages from different countries and communities. In particular, the ECOHIS questionnaire has been widely used to assess the impact of several oral problems on QoL; it has been frequently been applied in studies of preschool children, and is suitable and reliable for assessing preschool and elementary school students21 .The original ECOHIS assessed the impact of oral health problems, and the treatments used to address them, on the QoL of preschool children and their families21 .
The ECOHIS was originally developed in English to determine OHRQoL in preschool children, but has since been translated into different languages and validated ​​for use in various cultural settings5. The ECOHIS-T has acceptable validity and reliability22 .
The ECOHIS has been used for aesthetic and functional evaluations of oral tissues, malocclusion 23, dental trauma, cerebral palsy24 , autism spectrum disorder25, bruxism26 , children with cleft lip and palate, and HIV-positive and negative children27 . It has also been used to assess the effects of maternal depression and anxiety on pediatric OHRQoL 28, and to evaluate oral health in patients with head and neck cancers. Rodrigues et al.16 detected a negative correlation between OHRQoL evaluated by the ECOHIS and bruxism, while Alencar et al.26 reported that this correlation was mediated by anxiety. In a study conducted by Du et al. 25, a significant difference was observed in the ECOHIS scores of children with and without cerebral palsy and autism spectrum disorder. Birunghi et al. 27 detected a significant difference in the ECOHIS score between children with and without HIV. Costa et al.28 showed that the OHRQoL of mothers with maternal depression and anxiety was lower compared to healthy mothers. In the present study, no significant difference was found in total OHRQoL scores between healthy children and those with HM.The incidence of pain was closer to that reported in other validation studies, which ranged from 15 to 24%13. The rate of pain in the control and HM groups ranged from 20.1 to 44.8% and was significantly higher in the HM group than the control group. While the incidence of pain in the control group was comparable with the literature, the higher incidence in our HM children compared to previous studies may be associated with differences in the oral complications of treatments or pain perception of the patients, or with the effect of disease on oral tissues13 .
Du et al.25 conducted a study on healthy children with cerebral palsy and reported significant differences on all questions, including ones about self-image and social interactions on the CIS of the ECOHIS. In the present study, hesitancy to smile, and issues with self-perception and social interaction, were observed significantly more frequently in the HM than control group.
Khari et al. 29 reported that ECOHIS scores were negatively correlated with parental education level. Similarly, in the present study, education level and the ECOHIS and DMFT/dmft scores were negatively correlated.
The DMFT/dmft has been used to determine oral health in children and adults with type 1 diabetes mellitus 30, HIV-positive adults, and children receiving antineoplastic treatment31, as well as in studies of fetal alcohol syndrome32 , ALL and asthma33 , orthodontic anomalies 34, prosthodontic problems35, patients with a short dental arch35 , patients with high sugar intake36, and tooth brushing habits37 .
Dubey et al. reported that DMFT/dmft scores were higher in children with ALL than in those with type 1 diabetes mellitus or asthma33.
Olczak-Kowalczyk et al. showed that the DMFT/dmft scores during the post-treatment period are higher than those in children aged 5–18 years during and after antineoplastic CT38 . In the current study, the DMFT/dmft scores were similar between the healthy and HM groups. This result may be associated with late complications of antineoplastic treatments and a decrease in patient self-care skills.
When there is a normal occlusal relationship, the primary dentition are parallel to the permanent dentition. The occlusal relationships of teeth vary during the primary dentition period and are important for early diagnosis and treatment of malocclusion39. Dentition and dental occlusion status are important oral health parameters for both milk and permanent teeth. In the current study, the HM group had significantly more advanced dentition compared to the control group, and a higher incidence of Class 1 dental occlusion. Although this is advantageous for maintaining good oral health, in this study the difference may have been due to the age difference between the control and HM groups.
This study had some limitations. First, it was cross-sectional and certain parameters in the HM group could not be evaluated both before and after treatment. Second, a limited number of patients were included, and they were all from the same center. Third, the types and doses of CT contrast agents were unknown, as were the RT dose schedules.