An observational study in Oral Health Related Quality of Life (OHRQoL), Early Childhood Caries (ECC) and Traumatic Dental Injuries, sponsored by University of Lisbon. Completed at 1 site in Portugal. Open to participants aged 3 Years to 5 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-06-16.
Sponsored by University of Lisbon · Observational
The observational study aims to improve understanding of Oral Health-Related Quality of Life (OHRQoL) among preschool children in the District of Portalegre, Portugal, by examining the roles of sociodemographic, behavioral, and parental psychosocial factors, as well as the child's oral health status.
The study seeks to answer the following main research question: How do sociodemographic, behavioural, parental psychosocial factors, and the child's oral health status influence the Oral Health-Related Quality of Life (OHRQoL) of preschool children in the District of Portalegre?
This observational, analytical, and cross-sectional study aims to deepen understanding of the factors associated with Oral Health-Related Quality of Life (OHRQoL) among preschool children in the Portalegre District.
For participant selection, a probabilistic, multi-stage sampling process, stratified by type of preschool (public or private) and by municipality, was used. The final sample comprises 33 preschools, including 22 public and 11 private.
Data collection comprises two complementary components: a questionnaire completed by parents or caregivers and an intraoral examination for each participating child. The questionnaire comprises seven sections with multiple-choice and open-ended items. It collects information on the child's general health, access to oral healthcare, child and caregiver behaviors, OHRQoL, parental beliefs and attitudes regarding oral health, and sociodemographic characteristics. Distribution is carried out by educators and assistants from the institutions, ensuring delivery to parents or caregivers.
The intraoral examination collected data on oral hygiene, gingival health, the presence of dental caries, malocclusion, and traumatic dental lesions. All records were documented on a standardised form developed for the study. Examinations were carried out in a schoolroom with good natural and artificial lighting, using existing furniture. All infection control and cross-contamination prevention measures were implemented, including the use of disposable gloves and masks, as well as sterilized instruments.
The instruments used included a LED headlight, a flat intraoral mirror, a millimetre ruler, and a CPI (Community Periodontal Index) periodontal probe, in accordance with World Health Organization specifications, with a 0.5 mm ball tip.
The examination followed a standardized sequence: assessment of oral hygiene status, recording of gingival health, toothbrushing with a disposable toothbrush, drying the teeth with gauze, and subsequent evaluation of dental caries, malocclusion, and traumatic dental injuries.
631 studies on the registry are indexed under Gingivitis; 107 are open to participants now.
This study's enrollment of 454 is above the median of 93 across 116 observational studies indexed under Gingivitis.
Browse Gingivitis studies →University of Lisbon is the lead sponsor of 40 studies on the registry; 6 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Preschool-aged children attending schools in the district of Portalegre
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
All children who attended the selected classrooms were included in the study and who:
Exclusion Criteria:
-
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Oral Health-Related Quality of Life
The OHRQoL of preschool children will be assessed using the Early Childhood Oral Health Impact Scale (ECOHIS), included in the parent questionnaire. ECOHIS has 13 items: 9 evaluating the impact of oral problems on the child (Child ECOHIS) and 4 evaluating the impact on the family (Family ECOHIS). The child subscale includes four domains (symptoms, function, psychology, and social interaction), while the family subscale includes parental distress and family function. Items use a Likert scale from 0 ("Never") to 4 ("Very often"), with a "Don't know" option treated as missing. Participants with ≥2 "Don't know" responses in the child subscale or ≥1 in the family subscale will be excluded. The total ECOHIS score ranges from 0-52, with child and family scores ranging from 0-32 and 0-16. Higher scores indicate a more negative impact. Assessed at the moment when parents complete the questionnaire.
Time frame: Baseline
Level of Oral Hygiene
Oral hygiene was assessed using the soft debris component of the Simplified Oral Hygiene Index (OHI-S), following the criteria proposed by Rodrigues. For the primary dentition, the buccal surfaces of teeth 54, 61, and 82 and the lingual surface of tooth 75 were examined with a periodontal probe aligned parallel to the long axis of the tooth. If any of the indicated teeth were missing, the closest distal tooth was examined; if this tooth was also absent, the closest mesial tooth was assessed. Each tooth was assigned an integer score from 0 to 3, and the participant's final score was the mean of the values obtained. Assessed during the intraoral examination.
Time frame: Baseline
Gingival health
Gingival health was quantified using the ORI (Oral Rating Index), an oral classification index, following the criteria proposed by Kawamura. The ORI was based on the examination of four areas: the buccal surfaces of the maxillary anterior teeth, the buccal surfaces of the mandibular anterior teeth, the palatal surfaces of the right maxillary molars, and the lingual surfaces of the right mandibular molars. To determine each individual's ORI level, observable gingival characteristics and the accumulation of calculus and dental plaque were assessed, after which the individual was classified on an ordinal scale. The index was recorded without manual instruments, under natural light, and the decision was made within approximately 10 seconds. In cases of uncertainty, the examiner assigned the lowest score as the representative value for the individual. Assessed during the intraoral examination.
Time frame: Baseline
Presence of caries
For the diagnosis of dental caries, the procedures and criteria of ICDAS II were followed. The protocol described by this system recommended tooth brushing and drying prior to caries detection; therefore, the teeth were brushed with a disposable toothbrush and then dried with gauze. The system used two digits to record each tooth or surface: the first digit referred to restorations and sealants, and the second to the dental caries diagnosis. In this study, recording was performed per tooth, corresponding to the worst condition observed among its surfaces. In the ICDAS II system, codes 1 and 2 record early non-cavitated caries. However, because data collection occurred in kindergarten settings without the possibility of drying teeth with compressed air, code 1 for smooth-surface lesions could not be used. As anticipated in ICDAS II guidelines for epidemiological studies, codes 1 and 2 were therefore combined and recorded as "A" in this study. Assessed during the intraoral examination.
Time frame: Baseline
Presence of malocclusion
The criteria for assessing malocclusion followed Bjork, Zhou, and Grippaudo. Malocclusion was classified into three groups: (1) occlusal anomalies (anterior crossbite, edge to edge bite, increased overjet, anterior open bite, deep bite, posterior crossbite, scissor bite); (2) space anomalies (crowding); and (3) dentition anomalies (supernumerary teeth, agenesis, malformations). Anterior crossbite, edge to edge bite, increased overjet, anterior open bite, and deep bite were determined using horizontal and vertical overlap measurements. Horizontal overlap was recorded as the greatest distance between maxillary and mandibular incisors parallel to the occlusal plane; vertical overlap was the greatest distance between their incisal edges. Assessed during the intraoral examination.
Time frame: Baseline
Presence of dental trauma
The criteria used to diagnose traumatic dental injuries were based on WHO recommendations. Teeth affected by dental trauma were coded as follows: 0 - No signs of injury; 1 - Treated injury; 2 - Enamel fracture only; 3 - Enamel and dentine fracture; 4 - Pulp involvement; 5 - Tooth loss due to trauma; 6 - Other damage; 9 - Tooth excluded Assessed during the intraoral examination.
Time frame: Baseline
Psychosocial variables - Parental attitudes towards dental decay
The scale is composed of variables that correspond to factors included in the Parents' Beliefs and Attitudes Questionnaire. This scale assesses parents' beliefs and attitudes regarding the prevention of ECC, including perceived severity, perceived controllability, and external control. All items use the same response format: a 5-point Likert scale ('strongly agree', 'agree', 'neither agree nor disagree', 'disagree', 'strongly disagree'), scored from 1 to 5. Each variable score corresponds to the mean of the items within its respective factor, resulting in values ranging from 1 to 5. Lower scores indicate less positive beliefs and attitudes, whereas higher scores indicate more positive beliefs and attitudes. Assessment is performed at the moment when parents complete the questionnaire.
Time frame: Baseline
Psychosocial variables - Parental attitudes towards toothbrushing behaviour
The scale is composed of variables that correspond to factors included in the Parents' Beliefs and Attitudes Questionnaire. This scale assesses beliefs and attitudes related to the child's toothbrushing and includes two variables: the importance and intention of brushing the child's teeth, and parents' self-efficacy regarding the child's toothbrushing. All items use the same response format: a 5-point Likert scale ('strongly agree', 'agree', 'neither agree nor disagree', 'disagree', 'strongly disagree'), scored from 1 to 5. Each variable score corresponds to the mean of the items within its respective factor, resulting in values ranging from 1 to 5. Lower scores indicate less positive beliefs and attitudes, whereas higher scores indicate more positive beliefs and attitudes. Assessment is performed at the moment when parents complete the questionnaire.
Time frame: Baseline
Psychosocial variables - Parental attitudes towards child sugar snacking
The scale is composed of variables that correspond to factors included in the Parents' Beliefs and Attitudes Questionnaire. The scale of parents' beliefs and attitudes regarding the control of cariogenic diet includes the following variables: the importance and intention of controlling cariogenic food intake, and parents' self-efficacy related to the control of cariogenic diet. All items use the same response format: a 5-point Likert scale ('strongly agree', 'agree', 'neither agree nor disagree', 'disagree', 'strongly disagree'), scored from 1 to 5. Each variable score corresponds to the mean of the items within its respective factor, resulting in values ranging from 1 to 5. Lower scores indicate less positive beliefs and attitudes, whereas higher scores indicate more positive beliefs and attitudes. Assessment is performed at the moment when parents complete the questionnaire.
Time frame: Baseline
Variables related to the habits and behaviors of the mother/father/caregiver
This group of variables gathers information on parents' behavior regarding access to oral health care and toothbrushing, namely: frequency of toothbrushing, dental attendance, and frequency of dental visits. Assessed at the moment when parents complete the questionnaire.
Time frame: Baseline
Variables related to the child's behaviors
This group of variables includes those related to the child's oral hygiene, eating behaviors, and sucking habits: frequency of toothbrushing, night-time toothbrushing, use of fluoridated toothpaste, adult supervision during toothbrushing, consumption of foods and/or drinks after night-time brushing, foods and/or drinks consumed after night-time brushing, frequency of consumption of cariogenic foods between main meals, frequency of fruit and/or vegetable consumption, pacifier use and thumb sucking. Assessed at the moment when parents complete the questionnaire.
Time frame: Baseline
Variables related to access to oral health care
This group of variables collects information on the child's use of oral health care services: dental attendance, frequency of dental visits, information received about the child's oral health care and source of information about the child's oral health care. Assessed at the moment when parents complete the questionnaire.
Time frame: Baseline
Variables related to general health
This group of variables refers to information on the child's general health status and the importance attributed to the child's general and oral health: classification of the child's general health, classification of the child's oral health status, importance of oral health for the child's general health, presence of a relevant health problem or disease and health problem or disease. Assessed at the moment when parents complete the questionnaire.
Time frame: Baseline
Sociodemographic variables
This group of variables refers to the collection of social, economic, and demographic data from the study participants: sex, age, type of kindergarten, number of people in the household, child's cohabitants, child's nationality, parents' nationality and mother's educational level. Assessed at the moment when parents complete the questionnaire.
Time frame: Baseline
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
This study is completed, as verified in Apr 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
University of Lisbon