The current study presents new information about OHRQoL among UAE children before and following comprehensive dental reatment under GA. OHRQoL improved significantly after DGA treatment. Dental treatment under GA is not covered by most medical insurance companies in the UAE, and there is a long list of paediatric dental patients waiting to undergo GA in public sector hospitals providing DGA free of charge for UAE citizens. Our patient sample came from a large medical referral center in Al Ain city that accepted referrals from all over the UAE. Most participants were from Abu Dhabi and Al Ain compared to other UAE cities; the location convenience, acceptance of many insurances and faster treatment provision could be reasons for this.
The response rate in our study was higher than in another similar study . The primary caregivers involved in this study were the mothers. As mothers play the dominant role in raising the child and are involved in activities concerning the child’s welfare, therefore they were more willing to participate in the study. As such, their input and understanding of the scale was important.
The ECOHIS chosen for our study for pre-school age children was validated for many languages including the Arabic language and was found to be valid for measuring OHRQoL in children . Several other DGA studies [10 20,21] used the Parental-Caregivers Perceptions Questionnaire and Family Impact Scale (P-CPQ and FIS), a long version questionnaire (49 questions) designed for school-age children. A shorter OHRQoL questionnaire (13 questions) in the ECOHIS seems to have advantages in evaluating young children’s quality of life, as found in a Dutch study , where both questionnaires were used. Nevertheless, the ECOHIS had lately been found to have some limitations which could challenge its suitability for use with children affected by severe dental caries when compared with the new short-form P-CPQ and FIS scales . On the other hand, a UK study  that used ECOHIS showed its limited sensitivity to change due to the low levels of dental problems reported in their sample at baseline.
Comparisons of OHRQoL pre- and post-DGA between different studies should be ievaluated with care dur to the following reasons: first, the outcome may be influenced by the participants’ general oral health when the dental condition leading to DGA may have an impact on the results, the potential for improvement varying with the degree of severity. Second, the improvement in oral heath reported may be influenced by cultural differences; in some countries, more serious problems may overshadow oral health problems. Third, different methods and scales used to assess OHRQoL as well as the age of children in different studies may influence the results. The aforementioned factors were recently discussed in a systematic review .
Our positive effect of DGA in children with severe caries are in line with the conclusions made in the Jankauskiene et al. review  that DGA resulted in an improvement in quality of life for the child and for the family.
OHRQoL was introduced in 1978  and is defined as “that part of a person’s quality of life affected by the oral health”. This concept emphasized the holistic model of oral and general health. There are two main methods used to measure OHRQoL either by asking patients questions regarding her/his functions (e.g., biting, chewing), pain experience, psychological (self-esteem), and social wellbeing, or in case of young children by asking parents/caregivers (proxy measurement). The latter approach was followed in the present study.
By analyzing the distribution of child impact factors in our study, when asked regarding child pain symptoms, in the first survey before DGA, most of the parents suggested that their children occasionally complained of pain. The result of this study for this factor was different to that of the study conducted by Hashim et al. in Malaysian children . The majority of the parents in the present study suggested that their children occasionally had difficulty in drinking hot or cold beverages due to dental problems while in Pahel et al. , Hashim et al.  and Farsi et al.  studies, parents suggested that their children never/hardly ever complained. For the issue of difficulty in eating, the majority of the parents in our study suggested that their children occasionally had difficulty in eating due to dental problems or treatments; which was different from parents reported by Hashim et al.  and Pahel et al. .
Many parents reported that their child hardly ever or never complained of difficulty in pronunciation, missed preschool/school or daycare, had been irritated or frustrated, avoided smiling or laughing or avoided talking due to dental treatments or problems which were in accordance with other studies [11,12,27]. Explanation for a higher number of “occasionally or hardly ever” responses from parents of children with high dmft (dmft =13.8) score may be attributed to the fact that dental caries and infections are mostly chronic in nature and do not cause severe pain in many instances .
In the present study, most of the parents suggested that they have occasionally or hardly ever been upset, guilty, or taken time off from work because of their child's dental problems or dental treatments which was analogous to that of the study conducted by Pahel et al .
Our results were somewhat different from Pahel et al.  and Hashim et al.  studies for the issue related to financial impact where in these two studies; most of the parents said they had never have financial impact due to their child's dental problems or treatments while in our study the parents’ answer was “hardly ever”.
The parents reported greater impacts on boys than on girls which was similar to Jankauskiené study , while Klaassen et al. found no gender differences . Psychological factors may have played a role but confirming and explaining this finding will require further research. The highly educated parents with either secondary or tertiary education level reported higher child impacts than did parents with a lower level of education. This is an interesting finding that raises questions about different health values among parents in relation to their educational level. In the general population, a higher level of parental education is associated with better OHRQoL in children  but this might be different among parents of children with high levels of dental disease.
Most parents in the current study reported that their children had dental problems requiring treatment. This was reflected in this study by the high mean UAE-ECOHIS scores at baseline in both CIS (20.47) and FIS (11.33). The baseline and follow up mean scores of a similar study conducted among Chinese children in 2011  revealed lower mean ECOHIS scores compared to our study. Higher mean scores of ECOHIS were reported in other studies conducted among Australian children in 2016 and 2017 [32,33].
In our study, the mean scores significantly declined following dental treatment under GA, indicating an improvement in preschool children’s OHRQoL. Therefore, the UAE-ECOHIS was sensitive to changes in OHRQoL because the mean scores between pre- and post-treatment were statistically different. Overall, the magnitude of change of the UAE-ECOHIS following treatment which was assessed by the effect size (ES) was considered large (ES>0.7). The ES of both CIS and FIS was (2.8) and (2.2) respectively. A larger ES of CIS and FIS might be because all our sample children had severe ECC. Hashim et al. in 2018  reported ECC to be significantly related to OHRQoL of preschool children. The aforementioned study also found large effect size for CIS impact but medium ES of FIS impact . A Saudi study in 2014  showed that both CIS and FIS scales and all their subscales had large ES with the exception of social wellbeing, which showed moderate ES (ES=0.59).
The greatest relative changes were seen in the oral symptoms (ES= 3.4) and the parent distress (ES= 2.8). This indicated that treatment of ECC under GA had an even higher effect on preschool children’s OHRQoL compared to that of the family. Dental diseases frequently cause oral pain which might lead to oral dysfunction, i.e. difficulty in eating or drinking, and disturbed sleeping. Therefore, the impacts on the child were felt by parents a lot more than other domains. These findings were consistent with findings from other similar studies [2,18,31].
Although the ‘child self-image and social interaction’ domain of CIS sub-scale showed large ES, it was the lowest compared to the rest domains and this is in agreement with another similar study . Possible explanations might be that a child’s oral health and appearance was not important for peer-group acceptance at such a young age and may demonstrate limited parents’ knowledge about the social aspects of a child’s OHRQoL [29,34]. Interestingly; in this domain; the parents’ answers when questioned regarding their child avoiding smiling or laughing because of dental problems or dental treatments revealed a significant increase in the avoidance of smiling after treatment.
There were no statistically significant differences in UAE-ECOHIS change scores related to dmft except with child self-image and social interaction. A similar study found that ECOHIS change was statistically significantly higher in children with higher dmft scores compared with lower dmft . On the other hand, other studies conducted in India and Iran found no difference in the ECOHIS change in score relative to dmft scores [34,35]. Possible explanations to this might be related to the nature of detection of carious lesions using the dmft scoring system. The dmft score does not consider the stages of progression of carious lesions, for example early lesion or deep severe carious lesion were charted as decayed teeth only. Therefore, the use of a more precise charting techniques such as the ICDAS II or the Pulpal involvement, Ulceration due to trauma, Fistula and Abscess (PUFA/pufa) index for the detection of carious lesions may provide better clinical information in the investigation of OHRQoL in children [36,37].
Our study presented new information about the types of dental treatment under GA among children in UAE of the most frequently provided treatment for our study population was cervical pulpotomy (45%) and preformed metal crowns (46.5%) for the posterior teeth. In addition, 22.3% of anterior teeth were restored with zirconia crowns which was a preferred treatment option for its esthetics and retention properties, compared to 15.3% restored with composite restoration. This was different than other studies where most common treatment were either extraction or composite restorations . Restorative treatments were one of most common treatments in our study which is in agreement with previous studies in many European countries[40,41], North America, the Middle East, Asia[45,46], and New Zealand . This is in contrast with other centres that provide mostly exodontia services under GA among British and Australian children [39,48,49].
Limitations of the study: the present study was conducted in a centre that provided only same day DGA for ASA I and II patients, therefore medically compromised patients who are commonly treated with DGA were excluded. The reporting of pain could have been underestimated by parents because pain might not have been present at the time the questionnaires were completed. An attempt was made to conduct the study in a referral specialized center that treated children from all the Emirates of the UAE. However, most of the participants were from the Abu Dhabi Emirate. As discussed before, the reasons may be attributed to the following: the higher caries levels in Abu Dhabi Emirate, the ease of access and the full insurance cover provided for the benefit of Abu Dhabi Emirati children. An attempt was made to have the same parent who completed the first survey to do the same for the second survey, in very few cases; the same parent was not available, and we had to settle for the other parent to do so. The first survey was conducted on paper and second survey was conducted by a telephone call. This might have affected the consistency between the answers. There is a need for studies to involve more children including those with special needs and medically compromised children in all of the UAE emirates and also studies for surveying the effect of DGA on OHRQoL of school age children, with the questionnaires being completed by children themselves and not their parents/guardians.