Is pain during pediatric dental sedation associated with children ’ s pre-operative characteristics ? An exploratory study

Introduction: Little is known about the factors associated with the pain of children in dental treatment under conscious sedation. Objective: To investigate the association between preoperative characteristics and pain during pediatric dental treatment under sedation. Material and method: This exploratory study was conducted with 27 children in restorative treatment under sedation. Information on age, sex and experience of the children with previous dental treatment was obtained through interviews with parents. Oral health status, determined from the presence of dental caries, was verified using the dmf-t index. Pain was assessed by analyzing videos of the dental treatments by two previously calibrated examiners, using the items “legs”, “activity” and “crying” of the observational scale “face, legs, activity, consolability and crying” (FLACC). Data were analyzed using bivariate tests. Result: Most of the children (n=14, 51.8%) had no pain during dental treatment under sedation. Among the other children, lower or moderate pain scores (median 1.1; minimum 0 to 3.8) were observed. The FLACC scores did not vary according to sex (P=0.38), previous experience with dental treatment (P=0.32) and history with local anesthesia (P=0.96). The FLACC scores did not correlate significantly with age (Spearman rho= -0.08, P=0.67) and dmf-t (Spearman rho= -0.04, P=0.84). Conclusion: In this group of children, pain during dental treatment under sedation was of low frequency and intensity and did not associate with age, sex, oral condition and previous dental experience. Descriptors: Preschool; conscious sedation; pain assessment; dental caries; dental care for children; dental anesthesia. Mendonça, Daher, Corrêa-Faria et al. Rev Odontol UNESP. 2016 Sept-Oct; 45(5): 297-301 298


INTRODUCTION
Pain assessment in children is essential for identifying the damage that caused this unpleasant sensation and for providing the necessary care 1,2 .This assessment is not always easy, due to the limitations of verbalization of small children 3,4 and possible individual differences in the ways they react to pain 5 .Given these difficulties, observational scales have been used to assess pain, mainly in areas such as medicine 6 and nursing 7 .Among these scales is the FLACC (F = face, L = legs, A = activity, C = Consolability, C = crying), indicated for the assessment of pain in children from two to seven years of age 8 .The FLACC allows the assessment of behaviors related to pain, considering facial expressions, leg movements, activity, crying and consolability 8 .In pediatric dentistry, the FLACC has been used in studies comparing anesthetic techniques 9,10 , the removal of carious tissue 11 and the assessment of children's behavior 12 .
The perception of pain in children is associated with several cognitive, emotional and social factors 13 .Previous experience of painful procedures is one of the factors associated with the greater possibility of pain in subsequent procedures.Children who suffered during a painful procedure, like a lumbar puncture 14 , tend to have a more negative memory of the event, compared with those who did not suffer and they become more anxious in future procedures 13 .
In addition to previous experience with painful procedures, the perception of pain is related to the age of the child.According to a study conducted with children who underwent a painful medical procedure, older children can recall these procedures more easily and in greater detail, compared to younger children 14 .In dentistry, there is a scarcity of studies regarding factors associated with pain in children.
Considering that anxiety may exacerbate the perception of pain, it is desirable to use means such as sedation to reduce the occurrence thereof.Conscious sedation is an effective means of reducing anxiety 15 , in addition to having a temporary amnesia effect 16 .This amnesia effect could be of interest with patients undergoing potentially painful procedures, as it would reduce the chance that the child associate future procedures with previously vivid painful sensations.Despite these satisfactory effects with sedation, there is still no evidence regarding the influence of events during the pre-operative period and of children's characteristics in the experience of pain during dental procedures performed under sedation.
The investigation of these factors is important for establishing a dental treatment protocol appropriate to the patient, in order to minimize or control factors related to pain.Furthermore, reconciling conscious sedation to control factors associated with the experience of pain seems to be an effective path to successful pediatric dental treatment.
Therefore, the objective of the present study was to verify factors associated with the occurrence of pain during dental treatment of children undergoing conscious sedation.

Type of Research and Place of Study
This cross-sectional study was conducted in the clinic of the extension project "Center for Studies of Sedation in Dentistry" (CSSD), of the College of Dentistry at the Universidade Federal de Goiás (FOUFG) (Federal University of Goiás).

Population and Sample
The population for the present study included preschool children sent from the services connected to the Sistema Único de Saúde (Public Health System) (SUS) to the FOUFG for dental sedation.The present study included all the children that participated in a randomized clinical trial (n=27; registered in the clinical trials database: NCT02284204).These children were healthy, were between three and seven years old, presented carious lesions requiring restoration and needed conscious sedation.Children were excluded if it were not possible to analyze the videos produced during sedation.

Ethical Aspects
The present study was approved by the Committee for Ethics in Research of the Universidade Federal de Goiás (Federal University of Goiás) (protocol nº 307/2011, dated 31 October, 2011).Parents signed the free and informed consent form, authorizing the participation of the children for whom they are the legal guardians.

Dental Sedation Procedures
Initially, the children underwent the clinical oral exam to verify the presence of carious lesions requiring restoration and a medical exam to confirm the possibility of sedation.In this consult, information was also collected about age, sex, previous treatment and dental anesthesia experiences, and the presence of dental caries (dmf-t index), among others.
In the subsequent consultation, the child received the following sedatives orally: Midazolam Dormire  (Laboratório Cristália, São Paulo, Brasil), 0.5mg/kg (maximum dose of 20mg); and, Ketamine  (Laboratório Cristália, São Paulo, Brasil), 3.0mg/kg (maximum dose of 50mg).The Ketamine was used orally; it is only available commercially for intravenous administration.In Brazil, this medication is not available for oral use.After 15 minutes, the patient was sent to the dental office.There, the child received a mask for inhaling 100% oxygen or sevoflurane (5L/min for 5 minutes).The entire sedative protocol followed the safety guidelines of the American Academy of Pediatric Dentistry 17 .
During the sedation session, the child received the restorative treatment, performed by a pediatric dentist with an assistant, under local anesthesia (2% lidocaine with epinephrine 1:100,000) and absolute isolation.One upper or lower primary molar was restored during that consultation.The mother remained seated in a chair next to the child throughout the entire procedure.

Assessment of Pain
The clinical exams and the treatment were filmed without the child realizing it.The films were used in the assessment of the children's behavior.The assessment of behavior was conducted using an adaptation of the FLACC scale 8,18,19 .The scale is simple and has five categories that can each have a score from zero to two, with zero being a behavior that shows tranquility of the child/absence of pain and two being a behavior that shows severe pain (Table 1).Thus, the final score on the scale could range from zero to ten 8,18,19 .
In the present study, the category "face" was not assessed due to the impossibility of seeing the child's face, in detail, in the films.It was also not possible to assess the category "Consolability" since the children were sedated.With these modifications, the final score of the scale could range from zero to six.
The videos were viewed by two trained and calibrated observers who assigned scores from the scale, every minute.The intra-and inter-rater agreement was verified, receiving kappa values of 0.9 and 0.8, respectively.Finally, the mean of the scores was calculated for each FLACC category in a single session, and the scores for the three categories were totaled to obtain one final score per child, per session.

Statistical Analysis
The data were tabulated in such a way as to organize them in a database containing the following variables: dependent -score of the child's pain during treatment under sedation following the FLACC scale, considering the 3 categories separately as well as their sum; independent -age of the child (in months), sex of the child (female/male), history of dental treatment (yes/no), history of local anesthesia (yes/no) and oral condition of the child (index of dental caries, extracted/extraction indicated, filled -dmf-t).
The data were analyzed using the IBM SPSS v.17 software, significance level at 5%, with non-parametric bivariate analysis because the dependent variable presented non-normal distribution (Shapiro-Wilk test, P<0.05).The size of the effect for the strength of the association was calculated using the Mann-Whitney analysis.
Among the children participating in the present study, 14 (51.8%) had no pain during treatment under sedation (FLACC=0).Low to moderate pain scores were observed in the means of the categories of the FLACC scale and in the total sum of the scores in the three categories (Figure 1).
There was no statistically significant association between pain (FLACC) and sex, history of dental treatment or of dental anesthesia (Table 2).Furthermore, the size of the effect was small.The FLACC scores did not correlate significantly with the age of the child (Spearman rho= -0.08; P=0.67) or with the experience of caries (dmf-t index) (Spearman rho= -0.04, P=0.84).

DISCUSSION
This was an exploratory study in which the factors associated with pain in children undergoing restorative dental treatment under moderate sedation were assessed.The pain was assessed using  the FLACC scale, modified by removing the categories "face" and "Consolability".The removal of these categories may have led to underestimation of pain, since facial expression is a reliable indicator of pain in children 19,20 and may have affected the significance of the association among the variables studied.
The scores of the FLACC scale did not differ significantly among the children according to sex and age.According to a review published in 2009, the differences in relation to pain between boys and girls become evident at the onset of puberty 21 .Since the children who participated in the present study are between four and six years old, this fact would explain the observed result.This result also agrees with a recent review in which it was concluded that there is still no evidence about the differences between female and male sexes in the perception of pain 22 .Meanwhile, the fact that age is not associated with pain may be explained by the low variability in the age of the children included in the study, and the possible similarity in prior experiences of pain.
The memory of prior painful procedures has been associated with pain in subsequent procedures 13,14 .In the present study, the children with prior history of dental treatment had higher FLACC scores.However, no statistical significance was seen.There was also no significant difference in pain between children that had received dental anesthesia and those who had not.This lack of statistical significance may be explained by the small sample size and by the fact that most of the children had gone to the dentist and received dental anesthesia, making it difficult to observe significant differences with those who had not gone to the dentist or received anesthesia.
The present study has limitations such as the lack of assessment of children's faces and the small sample size.However, noting the scarcity of evidence regarding factors associated with pain during the dental treatment of sedated patients, the results obtained here should be considered and should encourage the development of studies with larger samples as well as other designs that allow the comparison of sedated and non-sedated children and other forms of pain assessment, including self-reporting among older children.

CONCLUSION
It is concluded that the group of children studied showed little pain during dental treatment under sedation.Also, that this symptom was not associated with age, sex, oral condition and previous dental experience.

Figure 1 .
Figure 1.Pain during restorative procedure performed under sedation according to FLACC scale scores.

Table 2 .
Results of the bivariate analysis for the association among the FLACC scale scores and the independent variables sex of the child, previous history of dental treatment and dental anesthesia Mann-Whitney Test.