Introduction

Early oral ageing syndrome (EOAS) is a broad concept referring to changes in oral health caused by systemic diseases of different origins, which are related to the current lifestyle. Non-carious conditions are among the oral problems found in EOAS and are responsible for the progressive, irreversible loss of mineral structure from the tooth in a premature, non-physiological way and without bacterial involvement. Depending on the severity of EOAS, changes can occur in other structures, such as the periodontium, pulp, bone, temporomandibular joint and muscles, compromising function, aesthetics and quality of life.1 The increase in the prevalence of non-carious conditions worldwide underscores the need for a more comprehensive understanding of the repercussions to oral health and aetiological factors within a transdisciplinary approach.1 2

The validated EOAS index can be found in books in the dental literature.1 With the increase in early, non-physiological tooth wear in the paediatric population, the Childhood EOAS (CEOAS) index was developed to investigate clinical signs and symptoms related to oral problems, such as the early loss of tooth structure in the deciduous dentition associated with the currently most prevalent enamel defects, which contribute significantly to oral ageing.3

The recognition of risk factors for CEOAS is essential for enabling the modulation or even elimination of causal factors through a transdisciplinary approach with the aim of preventing the progression of the problem, whenever possible. Acid erosion is one of the main risk factors recognised for tooth wear in children and adolescents and has a multifactorial aetiology with intrinsic and extrinsic sources. Intrinsic sources include gastro-oesophageal reflux disease, eating disorders (bulimia and anorexia) and persistent regurgitation,4–13 whereas extrinsic sources include acidic foods (sodas, citric taffy and chewing gum, fruits and juices of acidic fruits), sports and energy drinks, the practice of sports (swimming), use of electronic cigarettes (vaping) and some medications (antibiotics, iron supplements, inhalers for asthma, analgesics and antipyretics).14–25

Determining the causes of erosive lesions in the deciduous dentition is of extreme importance for preventing the same aetiological agents from perpetuating in the permanent dentition. Children with dental erosion on deciduous teeth are four to five times more likely to have this problem in the permanent dentition.26 27 Besides erosive wear, abrasion and attrition are also determinants of the early loss of dental structure. Non-erosive tooth wear is common among children and adolescents and increases progressively with age independently of sex.28 Oral hygiene habits (brushing duration, brushing method, type of brush and abrasiveness of toothpaste) are among the risk factors for abrasion, especially when combined with acidic beverages and acidic saliva.18 29–33

Risk factors for attrition include sleep and awake bruxism, which occur due to the increase in testosterone levels in male adolescents between 10 and 18 years of age, and the use of medications that stimulate the central nervous system, such as those for attention deficit/hyperactivity disorder, coeliac disease, respiratory problems, and emotional and behavioural problems.34–38 The severity of wear due to attrition is proportional to the severity of sleep and awake bruxism.39 This wear can alter the vertical dimension of occlusion (VDO) and lead to an inadequate chewing pattern as well as dysfunctions of the temporomandibular joint.40

Another factor associated with the early loss of dental enamel causing functional and aesthetic impairment is developmental defects of enamel, which are characterised by an abnormal dental mineralisation process. Enamel defects, such as fluorosis, molar incisor hypomineralisation and deciduous molar hypomineralisation, weaken the enamel structure, making it more vulnerable to fractures and wear.2

Numerous indices are used for the assessment of non-carious diseases, which are categorised based on aetiology, which makes the analysis of associated factors and knowledge on the actual prevalence of such conditions difficult. The CEOAS index is the first to assess clinical signs and symptoms related to the early loss of tooth structure associated with the currently most prevalent developmental defects of enamel, using specific questions that address all possible aetiologies.

MethodsEthical aspects

The study will be conducted in accordance with the ethical precepts stipulated in the Declaration of Helsinki (World Medical Association Declaration of Helsinki, 2008) as well as the norms governing research involving human subjects stipulated in Resolutions 466/12 and 510/2016 of the Brazilian National Board of Health and has received approval from the human research ethics committee of Universidade Nove de Julho (process number: 6.713.724. Approved on 20 March 2024). The study was registered in ClinicalTrials.gov (NCT06381414, 23 April 2024). Legal guardians will agree to the participation of the children by signing a statement of informed consent. The participants will be informed that they may withdraw from the study at any time for any reason, if they so wish. The researchers will also be able to remove participants from the study if deemed necessary. The data collection for the study began in May 2024, with an expected completion date in June 2025.

Objective

The aim of the study is to identify the prevalence of premature tooth wear in the deciduous dentition using the CEOAS index and investigate possible aetiological factors as well as consequences for the VDO.

Study design

This protocol follows the checklist for cross-sectional studies as outlined by the Strengthening the Reporting of Observational Studies in Epidemiology statement.41 The study will be conducted with children enrolled at the paediatric clinic of Universidade Nove de Julho, who will be examined in a single session during the visit to the clinic.

Sample size

A sample size of 164 individuals was calculated to estimate a proportion of the occurrence of the outcome (CEOAS) with a 15% range for the CI. With an increase of 10% to compensate for possible dropouts and refusals, this number should be 183. The calculation (using the Wald method) considered a 95% CI and 39.64% expected rate of erosion in the primary dentition,42 since the CEOAS is a new index and no studies have been published on its use. This calculation was performed using the online version of the PSS Health tool.43

Participants

One hundred eighty-three healthy children aged 3–6 years of both sexes with no distinction regarding race or ethnicity enrolled for treatment at the paediatric dental clinic of Universidade Nove de Julho who meet the inclusion criteria will be selected.

Exclusion criteria

Children with amelogenesis or dentinogenesis imperfecta.

Children undergoing orthodontic treatment.

Children with a genetic syndrome.

Calibration of examiner

The assessments will be conducted by a single examiner, who was previously calibrated before the start of the study. The training involved the use of photographs for the diagnosis of enamel developmental defects, using the criteria of the European Academy of Paediatric Dentistry (EAPD) (deciduous molar hypomineralisation), Dean’s index (fluorosis) and the CEOAS (tooth wear) index. Intraexaminer agreement was assessed using the weighted Kappa coefficient to measure the reproducibility of the exams performed by the examiner at two distinct time points. The examiner repeated the tests after 1 week interval, obtaining a score of 0.92.’

EAPD criteria for diagnosis of deciduous molar hypomineralisation

Demarcated opacities: abnormal translucence of enamel identified as well-defined areas not less than 1 mm in size, creamy white/yellowish brown in colour.

Post-eruption enamel fracture: fracture of enamel when affected tooth erupts as a result of masticatory forces in the affected area.

Atypical caries: caries with size, shape and location that does not correspond to habitual caries.

Atypical restoration: restoration with size similar to extent of hypomineralised lesion still with surrounding halo.

Hypersensitivity: acute sensitivity to stimuli that do not generate an intense response in a sound tooth.

Atypical extraction: absence of a deciduous second molar that had been recorded on the patient chart as a hypomineralised tooth and is accompanied by the presence of other affected molars or molars with atypical restorations.

The condition will be classified based on severity, distinguishing the following types of lesions:44 45

Mild:

Demarcated opacities on enamel without fracture.

Occasional sensitivity to external stimuli, such as air or water, but not during.

Drying

Severe

Demarcated opacities on enamel with fracture.

Caries.

Persistent or spontaneous hypersensitivity during an action, such as brushing.

Dean’s fluorosis index

Dean’s index is a measure used to assess the prevalence and severity of fluorosis. Its classification is presented in table 1 46

Questionnaire

The questionnaire is an instrument that enables collecting information on aetiological factors related to early tooth wear. This is an important tool in directing the patient to the transdisciplinary team, who confirm the diagnosis as well as perform clinical and pharmacological (if needed) management. The distribution of the questionnaire will be divided in accordance with the possible aetiologies described in the literature with a higher level of evidence47–49 and divided into four main topics: general health (table 2); sleep quality (table 3); dietary habits (table 4); hygiene and parafunctional habits (table 5). The questionnaire will be applied in interview form to the legal guardians of the children who reside at the same address. This part will be administered by an external researcher prior to the clinical examination.

Table 5

Hygiene and parafunctional habits

CEOAS index

The aim of the CEOAS index is to investigate clinical signs and symptoms related to the early loss of dental structure associated with the currently most prevalent enamel defects, which significantly contribute to oral ageing. The clinical management of wear is also addressed in CEOAS scores 1, 2 and 3. Indices currently used for non-carious conditions do not concomitantly address enamel defects, which makes the CEOAS index innovative and of extreme importance for epidemiological surveys. Understanding the prevalence of factors that accelerate the early ageing process either separately or synergically is useful for the establishment of novel clinical treatment strategies.

The CEOAS index involves scores of 0–3 for the assessment of tooth wear and dental management, whereas scores of I, II and III are used concomitantly in cases of the presence of enamel defects, as shown below:

CEOAS 0: absence of signs and symptoms of CEOAS

CEOAS 1: clinical findings compatible with chronological age and oral age. First clinical signs (facets with initial wear on enamel level without altering function), without symptoms. Such cases require clinical follow-up.

Due to the lack of studies on the physiological wear pattern in the deciduous dentition, slight tooth wear without symptoms, functional or aesthetic problems compatible with physiological wear are considered in this score.

CEOAS 2: signs of wear not compatible with chronological age (facets with deep wear, with dentin exposure and compromised function) and symptoms of hypersensitivity. May include gingival recession. Such cases require restorative treatment and management of sensitivity. Due to the lack of studies on the physiological wear pattern in the deciduous dentition, atypical tooth wear for the age of the patient (pathological wear), with symptoms as well as functional and aesthetic problems, are considered in this score.

CEOAS 3: signs of severe wear not compatible with chronological age, with pulp involvement (inflammation or necrosis), compromising function and the stomatognathic system. May have tooth fissures, root fissures, tooth fractures, gingival recession and changes in the temporomandibular joint. Loss of the tooth may occur. Such cases require invasive treatment (endodontic, restorative, rehabilitative or extractive).

CEOAS I: in the presence of deciduous second molar hypomineralisation (DSMH) with demarcated opacities and without post-eruption fractures, the CEOAS I score should be recorded concomitantly with the 1, 2 or 3 score detected in the clinical examination.

CEOAS II: in the presence of DSMH with post-eruption fractures, the CEOAS II score should be recorded concomitantly with the 1, 2 or 3 score detected in the clinical examination.

CEOAS III: in the presence of dental fluorosis, the CEOAS III score should be recorded concomitantly with the 1, 2 or 3 score detected in the clinical examination.

The CEOAS index can be used in the simplified version with the score of the greatest severity found. In the complete version, the CEOAS index with an odontogram on which each tooth is assigned a score.

Examination methods of administration of index

Clinical examinations will be performed at the dental clinic by two trained and calibrated examiners under standard conditions with the child in the sitting position. The teeth will be dried with compressed air and examined with the aid of a disposable mouth mirror under artificial light. All cross-infection control measures will be adopted. The assessment of sensitivity will be performed with compressed air directed at the tooth for one second. Scores will be recorded on the odontogram for the deciduous dentition. The examiners will not have access to the information obtained on the questionnaires.

VDO will be measured with the participant seated, head aligned with the body, gaze fixed on a specific point and teeth in centric occlusion. The following distances will be measured with the aid of digital callipers: (1) distance from labial commissure to corner of eye and (2) distance from base of nose to chin.50

The questionnaire will be administered in interview format to the legal guardians who reside at the same address as the children. This will be performed by an external examiner prior to the clinical examination.

Statistical analysis

The CEOAS will be the outcome variable: CEOAS 0 and 1 = ‘without premature early ageing’; CEOAS 2 and 3 = ‘with premature early ageing.’ Poisson regression analysis will be used to test associations between the independent variables, VDO, sex, age and aetiological variables from the questionnaire, enabling the calculation of prevalence ratios (PR) and respective 95% CIs. The bivariate analysis will be conducted first, followed by the multivariate analysis. All variables with a p value<0.20 in the bivariate analysis will be incorporated into the multivariable model. Variables with a p value<0.05 after adjustments will remain in the final model.