Patient-reported measures outcomes: modern evaluation of oral health.

Patient reported outcomes have become important, with instruments (patient reported outcomes measures - PROMs) being used to assess treatment success and patient satisfaction. In this editorial, the dental PROM context is presented, and submissions are invited for a special collection from BMC Oral Health entitled 'Patient-reported outcomes in dentistry'.

Oral health status of 12-year-old children in Lisu minority ethnic group in China: a cross-sectional study.

BACKGROUND: Lisu is an ethnic minority group and most of them are living in Yunnan, China. This study investigated the oral health status among 12-year-old Lisu children in Yunnan. METHOD: This survey employed a multistage sampling method to recruit 12-year-old Lisu children. Two calibrated dentists performed the oral examinations in the primary schools. They examined dental caries, gingival bleeding and dental fluorosis using the diagnosis criteria recommended by the World Health Organization. A self-administrated questionnaire was distributed to the children to collect their sociodemographic background information and oral health-related behaviours. A chi-square test, the Mann-Whitney U test, zero-inflated negative binomial (ZINB) regression and multivariate logistic regression were used for statistical analysis. RESULTS: This survey invited 512 children, and 482 children (48% boys) participated in the study (response rate: 94%). Their caries prevalence was 35% and their caries experience in mean (SD) DMFT scores was 0.63 (0.10). The mean (SD) DT score was 0.60 (1.10), consisting 95% of the mean DMFT scores. No dental fluorosis was observed; whereas 426 children (88%) had gingival bleeding. Results of ZINB model indicated sex and sugary-snacking habits were related to the dental caries experience (p < 0.05). The gingival-bleeding prevalence was associated with the mother's education level, the child's monthly-pocket money and daily toothbrushing frequency (p < 0.05). CONCLUSION: Dental caries and gingival bleeding were prevalent among 12-year-old Lisu children in the Yunnan province in China, and most of the decayed teeth were unrestored. Dental fluorosis was not observed in the children.

Erosive tooth wear among preschool children in Hong Kong.

OBJECTIVE: This study aimed to assess the prevalence of erosive tooth wear among 3- to 5-year-old children in Hong Kong and to determine the effect of socio-economic factors, dental habits, and oral hygiene on their dental erosive wear status. METHODS: Stratified random sampling was adopted. Their parents were asked to complete a questionnaire regarding their children's backgrounds. A single examiner evaluated the children for erosive tooth wear using Basic Erosive Wear Examination (BEWE) criteria. Multiple logistic regression was used to determine the relationship between erosive wear and the children's socio-economic factors, dental habits, and oral hygiene. RESULTS: 1204 children participated in this study. Prevalence of erosive tooth wear (BEWE score > 0) was 14.9%. Among these, 153 children (12.8%) had initial wear, 21 children (1.8%) had distinct tooth loss, and five (0.4%) had severe erosive wear. Prevalence of erosive wear among the 3-, 4-, and 5-year-old children was 10.7%, 15.0%, and 17.7%, respectively. Increasing age, the low education of mother and high plaque scores were risk factors of erosive wear (P < 0.05). CONCLUSION: Prevalence of erosive tooth wear is low among preschool children in Hong Kong. The erosive tooth wear prevalence increased with increasing age, lower education of mother, and poorer oral hygiene.

Dental caries status and its associated factors among 5-year-old Hong Kong children: a cross-sectional study.

BACKGROUND: This study investigated dental caries status and its associated factors among 5-year-old children in Hong Kong. METHOD: This cross-sectional survey was conducted in 2016. It comprised a questionnaire survey and a clinical examination. Kindergarten children aged 5 were recruited using a multistage sampling method. Parents of the participating children were asked about their children's demographic information, sugary snacking behaviours, and oral health-related behaviours and about their own oral health knowledge. One trained dentist performed oral examinations on the children. Caries experience was measured using the dmft index. The relationships between the dmft scores and background information, sugary snacking behaviours, oral health-related behaviours and parental dental knowledge were studied using a zero-inflated negative binomial (ZINB) regression analysis. RESULTS: A total of 570 children were invited to participate, and 501 completed the oral examination (response rate: 88%). The prevalence of dental caries was 55%, and the mean dmft score was 2.7 ± 3.7. Decayed teeth (dt) constituted 93% of caries experience. ZINB analysis found that children who visited a dentist, who were taken care of primarily by grandparents and whose parental dental knowledge levels were moderate had higher dmft scores. Children who ate sugary snacks more than twice daily, had irregular dental attendance and lived in low-income families had a significantly higher chance of having dental caries. CONCLUSIONS: Dental caries was prevalent among 5-year-old Hong Kong children, and most of the decayed teeth were untreated. The caries prevalence of the children was related to their frequency of sugary snack intake, dental attendance and socio-economic background.

Tools Evaluating Child Oral Health-Related Quality of Life.

OBJECTIVES: This study aimed to systemically review the tools developed for evaluating oral health-related quality of life (OHRQoL) in preschool children. METHODS: Two reviewers systematically searched English-language publications within PubMed, Embase, Scopus, and Web of Science. They screened the titles and abstracts and retrieved the full texts of the selected publications. Studies which developed, validated, or culturally adapted an OHRQoL tool used in preschool children were included. They recorded information regarding tool characteristics, item configuration, discriminative validation, the aim of assessment, and the target group. RESULTS: The study included 59 publications and identified 12 tools for assessing OHRQoL in preschool children. Seven tools were tailored for preschool ages. Most of the scales were generic oral health measures. Dental caries was the most commonly used oral condition for assessing a tool's discriminative validity. Eight tools required parental proxy reports. Three tools were both child-administrated and parent-administrated. One tool was designed to be answered solely by children. Ten tools assessed the oral health-related impact on children, including oral condition-related, functioning, environmental, and emotional/social domains. Four tools included items regarding the impact on both children and family. CONCLUSIONS: This review identified 12 tools developed for evaluating OHRQoL in preschool children, 7 of which were tailored for preschool age. The 12 tools were validated but incomprehensive due to the subjective and multidimensional nature of the OHRQoL concept. Researchers can choose a suitable tool for their studies by understanding the basic characteristics and item setting of the tools. Researchers can have an overview of the tools developed for evaluating OHRQoL in preschool children. They can use the findings from this review to choose a suitable tool for their studies regarding the OHRQoL in preschool children.

Parental perspectives on the use of silver diamine fluoride therapy to arrest early childhood caries in kindergarten outreach dental services: A qualitative study.

OBJECTIVES: This study aimed to explore parental perspectives on an outreach dental service and silver diamine fluoride (SDF) therapy to arrest and prevent early childhood caries. METHODS: This qualitative study collaborated with an outreach service offering SDF therapy to kindergarten children and oral health education to the children's parents. The study was conducted in 2018 using purposive sampling of participating parents from selected kindergartens in Hong Kong until data saturation was reached. Five parents were recruited from each kindergarten for a focus-group discussion. The data were manually coded for thematic analysis. RESULTS: Ten focus-group discussions with 49 parents were held to achieve data saturation. The oral health education largely met the parents' expectations regarding enriching their child's oral health knowledge, raising their child's dental awareness, and promoting parent-assisted toothbrushing. Some parents did not consent to their children undergoing SDF therapy because it permanently stains caries black, which adversely affects appearance. They were also concerned about potential toxicity of SDF. Parents who did consent preferred the arrest and prevention of dental caries over aesthetics which are temporary until the primary teeth exfoliate. CONCLUSIONS: This outreach dental service improved parental dental knowledge. Some parents were generally satisfied with the outreach dental services, preferred caries arrest over aesthetics, and accepted SDF therapy. However, some parents worried about SDF toxicity. The results of this study provide rich, in-depth, and multi-dimensional information about parents' experiences of taking the outreach dental service and their opinions about SDF therapy. CLINICAL SIGNIFICANCE: Dentists can use the arguments from this study to form a protocol for communicating with parents before SDF therapy. This study shows that outreach dental services improve dental knowledge. Some parents prefer caries arrest over aesthetics and accept SDF therapy; however, some parents worry about SDF toxicity.

Comparing two fluoride therapies for caries management in young children: study protocol for a randomised clinical trial.

BACKGROUND: Silver diamine fluoride (SDF) and sodium fluoride (NaF) are widely used for caries management. The objectives of this study are (i) to compare the caries-arresting and caries-preventive effects of SDF and NaF in young children, (ii) to determine children's and parents' acceptance of these fluoride therapies and (iii) to investigate the short-term (1 day) and long-term (1 year) adverse effects of these fluoride therapies. METHODS/DESIGN: This is a randomised, double-blind, active-controlled clinical trial to be conducted in Hong Kong kindergartens. The study has received approval from the local institutional review board. Written consent will be obtained from the parents/guardians before the study. The study will recruit at least 688 healthy 3-year-old children. This sample size is sufficient for an appropriate statistical analysis. Stratified randomisation will be performed for intervention allocation. The two intervention groups are 38% SDF and 5% NaF varnish applied on six primary upper anterior teeth. At baseline, one trained examiner will perform clinical examinations of the children in the kindergartens. The caries experience and oral hygiene status of each child will be recorded using the decayed, missing (due to caries) and filled primary tooth index and visual plaque index, respectively. Then, an independent operator will apply the assigned fluoride after the dental examinations. The examiner, the children and their parents will be blinded to the intervention allocation. In addition, a research assistant will evaluate the child's acceptance using interval rating scales for children's uncooperative behaviour. The examiner will then visit the children the next day to study the short-term potential adverse effects of the fluoride therapies. The same examiner will perform a follow-up examination after 1 year to evaluate the children's caries experiences, their oral hygiene statuses and the adverse effects of the fluoride. Parental questionnaires will be used to assess parental satisfaction and concerns about the fluoride therapies. DISCUSSION: This study provides essential information about using SDF in an outreach kindergarten service for caries management from different aspects, which include the caries-arresting and caries-preventive effects, the adverse effects and children's and parents' acceptance. The success of the service can help to increase the adoption of SDF to reduce the global burden of early childhood caries. TRIAL REGISTRATION: ClinicalTrials.gov NCT04399369 . Registered on May 2020.

A Concise Review on Qualitative Research in Dentistry.

Qualitative research collects non-numerical data that explores human behaviour, attitudes, beliefs and personality characteristics unamendable to quantitative research. The qualitative research questions are open-ended, evolving and non-directional. The study design is flexible and iterative. Purposive sampling is commonly used. The sample size is determined by theoretical saturation. Data collection is generally through in-depth interviews, focus groups and observations. Qualitative research commonly uses thematic analysis and framework analysis, although there is no consensus on analysing qualitative data. The reporting format can be comprehensive, a summary, developmental or selective, subject to the research question. Qualitative research's potential functions are to describe the form or nature of what exists (contextual), to examine the reasons for or associations between what exists (explanatory), to appraise the effectiveness of what exists (evaluative), and to aid the development of strategies (generative). Qualitative research can be time consuming to conduct because it explores evolving questions; difficult to generalise because it recruits limited participants; and arduous when it comes to making systematic comparisons because responses are subjective. However, qualitative research can provide depth and detail, create openness, simulate people's individual experiences and avoid pre-judgements. This concise review provides an overview and suggestions for dental researchers when conducting a qualitative study.

Global Oral Health Policies and Guidelines: Using Silver Diamine Fluoride for Caries Control.

Silver diamine fluoride (SDF) was developed in Japan in the 1960s. It is a clear solution containing silver and fluoride ions. Because of its anti-bacterial and remineralizing effect, silver diamine fluoride has been used in managing dental caries for decades worldwide. This paper aims to summarize and discuss the global policies, guidelines, and relevant information on utilizing SDF for caries management. SDF can be used for treating dental caries in most countries. However, it is not permitted to be used in mainland China. Several manufacturers, mainly in Australia, Brazil, India, Japan, and the United States, produce SDF at different concentrations that are commercially available around the world. The prices differ between contents and brands. Different government organizations and dental associations have developed guidelines for clinical use of SDF. Dental professionals can refer to the specific guidelines in their own countries or territories. Training for using SDF is part of undergraduate and/or postgraduate curriculums in almost all countries. However, real utilization of SDF of dentists, especially in the private sector, remains unclear in most places because little research has been conducted. There are at least two ongoing regional-wide large-scale oral health programs, using SDF as one of the components to manage dental caries in young children (one in Hong Kong and one in Mongolia). Because SDF treatment does not require caries removal, and it is simple, non-invasive, and inexpensive, SDF is a valuable strategy for caries management in young children, elderly people, and patients with special needs. In addition, to reduce the risk of bacteria or virus transmission in dental settings, using SDF as a non-aerosol producing procedure should be emphasized under the COVID-19 outbreak.

Translation and validation of the Chinese version of the scale of oral health outcomes for 5-year-old children.

OBJECTIVE: To adapt the oral health-related quality of life (OHRQoL) measurement tool SOHO-5 (scale of oral health outcomes for 5-year-old children) for use in Chinese populations, and to investigate the validity and reliability of the Chinese version of SOHO-5 (C-SOHO-5). MATERIALS AND METHODS: The draft C-SOHO-5 was developed by a forward-backward process and pilot-tested on 20 child-parent pairs. The final version was tested on a sample of 5-year-old children and their parents. Clinical examinations were conducted to record the children's caries experience. The reliability of C-SOHO-5 was assessed by both internal consistency and test-retest reliability. Its discriminant validity and construct validity were also investigated. RESULTS: A total of 249 child-parent pairs participated in this study. Cronbach's alpha values for the child's version of C-SOHO-5 (C-SOHO-5c) and the parental version of C-SOHO-5 (C-SOHO-5p) were 0.71 and 0.82, respectively. The intraclass correlation coefficient values for C-SOHO-5c and C-SOHO-5p were 0.85 and 0.46, respectively. Both the child's and the parental version were able to discriminate the caries and caries-free children groups. Children with caries experience had higher mean ranks of the total score of both C-SOHO-5c and C-SOHO-5p than those of the caries-free children (134.9 vs. 113.8, P = 0.015; 134.7 vs. 93.2, P < 0.001). In addition, the total scores of both child's and parental reports were significantly correlated with the global rating questions. CONCLUSION: The C-SOHO-5 demonstrated good reliability and validity. This tool, which uses both child's and parental reports, can be used to assess the OHRQoL of 5-year-old children in Chinese-speaking communities.

Preventing early childhood caries with silver diamine fluoride: study protocol for a randomised clinical trial.

BACKGROUND: Silver diamine fluoride (SDF) solution is effective in arresting early childhood caries (ECC). Previous studies have suggested that it might exert a preventive effect in managing ECC. However, no well-designed clinical trials have yet been performed to study the effect of SDF on caries prevention. The objective of this randomised clinical trial is to determine whether 38% SDF solution is superior to 5% sodium fluoride (NaF) varnish in preventing new carious lesions in primary anterior teeth. METHODS/DESIGN: This is a phase II, single-centre, randomised, double-blind, active-controlled, parallel-group pragmatic trial. The hypothesis tested is that 38% SDF would be more effective than 5% NaF in preventing new caries development in primary anterior teeth. Approximately 730 3-year-old children who are generally healthy and with parental consent will be recruited from Hong Kong kindergartens. This sample size will be sufficient for appropriate statistical analysis of a superiority trial with 90% power, allowing for a 20% drop-out rate. Stratified randomisation will be adopted for allocating the intervention. The intervention will either be 38% SDF or 5% NaF (as a positive control) therapy on primary upper anterior teeth. A single trained examiner will conduct a dental examination every 6 months until 30 months in kindergarten. Another operator will provide fluoride therapy immediately after each dental examination. The examiner, children and children's parents will be blinded to the treatment allocation. A questionnaire survey will be conducted to study the children's oral health-related behaviours and socioeconomic backgrounds. Chi-square tests, t tests, regression analyses and survival analyses will be adopted for data analysis. DISCUSSION: The effectiveness of 38% SDF in preventing ECC remains uncertain. If the results are as anticipated, care standards using 5% NaF for ECC prevention will be changed. In addition, the results will be widely available and increase the adoption of SDF in other countries to reduce the global burden of ECC. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04075474. Registered on 30 Aug 2019.

An Introduction to Assessing Dental Fear and Anxiety in Children.

Fear and anxiety constitute an important theme in dentistry, especially with children. Anxiety and the fear of pain during dental treatment can lead to avoidance behaviour, which contributes to perpetuating fear and anxiety of dental care. Understanding and assessing dental fear and anxiety in children is important for delivering successful dental care with high satisfaction in this age group. Among the vast assessment method options available today, self-report assessment, parental proxy assessment, observation-based assessment, and physiological assessment are the four major types for dental fear and anxiety in children. Each method has its own merits and limitations. The selection of a method should be based on the objectives, validity, and setting of the assessment. The aim of this paper is to review and discuss the assessment methods for dental fear and anxiety in children.

Dental Fear and Anxiety of Kindergarten Children in Hong Kong: A Cross-Sectional Study.

Objectives: The objectives of this cross-sectional study were to investigate the fear level of kindergarten children in the general population during dental outreach in a familiar kindergarten setting, and to explore the factors associated with the dental fear of kindergarten children. Method: Consecutive sampling method was used to select kindergarten children aged 3 to 5 to participate in a questionnaire survey and an outreach service. A behavioural observation type of instrument for dental fear and anxiety assessment-Frankl Behaviour Rating Scale (FBRS)-was chosen to investigate the fear level of the children. Bivariate analyses between various factors and children's dental fear and anxiety were carried out using Chi-square test. Results: A total of 498 children participated in this study. Almost half (46%) of the children have had caries experience, and the mean dmft score was 2.1 ± 3.4. The prevalence of dental caries was 32%, 43%, and 64% in the 3-, 4- and 5-year-olds, respectively. Only 4% of the children scored negatively for dental fear and anxiety (95% CI 2.3%-5.7%). Children at three years of age displayed more dental fear and anxiety than children of older ages, but the difference in dental fear and anxiety among the genders and caries status was not statistically significant. Most of the children (92%) brushed daily, but only 20% of them used toothpaste. Most (85%) of them had never visited the dentist, and over 70% of them were mainly taken care by their parents. High levels of positive and cooperative behaviour and low levels of fear were found in this population. No statistical significance was found between the child's dental fear and any factors except age. Conclusion: Children generally displayed low fear or anxiety levels in a dental outreach consisting of a non-invasive oral examination and preventive treatment in a familiar kindergarten setting. Conducting regular outreach dental services to kindergartens by providing oral examination and simple remineralisation therapies could be a promising strategy to not only control childhood caries, but also manage and reduce dental fear and encourage long term dental attendance in line with the medical model.

A Kindergarten-Based Oral Health Preventive Approach for Hong Kong Preschool Children.

Early childhood caries (ECC) remains the single most common chronic childhood disease. Untreated caries can cause tooth loss and compromised dentition. Severe ECC can also influence nutrition intake, cognitive development, general health and quality of life. In Hong Kong, approximately half of 5-year-old children suffer from ECC, and more than 90% of these caries remain untreated. Thus, the development of effective strategies for promoting the oral health of preschool children is warranted. The Faculty of Dentistry of the University of Hong Kong has provided kindergarten-based dental outreach services to selected kindergartens since 2008. In 2020, the project expanded to serve all kindergarten children in Hong Kong. The aim of the service is to improve oral health through the prevention and control of ECC among preschool children. The service provides dental screening and silver diamine fluoride treatment for ECC management. In addition, the parents receive oral health talks, and teachers receive training in delivering regular oral health education at kindergarten. The objectives of this service are to improve oral and general health of preschool children, develop the children's good oral health-related behaviours, maintain the children's psychological well-being and reduce the burden on their family. This paper describes this kindergarten-based dental outreach service.

Arresting early childhood caries using silver and fluoride products - A randomised trial.

OBJECTIVE: The aim of this randomised non-inferiority clinical trial was to compare the effectiveness of semi-annual (every six months) applications of 25 % silver nitrate (AgNO3) solution followed by 5 % sodium fluoride (NaF) varnish to semi-annual applications of 38 % silver diamine fluoride (SDF) solution in arresting early childhood caries (ECC). METHODS: Three-year-old children with active cavitated carious lesions were recruited and randomly assigned to two intervention groups. Children in Group A received semi-annual applications of 25 % AgNO3 solution followed by 5 % NaF varnish on carious lesions. Children in Group B received semi-annual applications of 38 % SDF solution followed by a placebo varnish. One trained dentist assessed ECC status at baseline and in all follow-up examinations. An independent operator performed the interventions. The dentist, the children, and their caretakers were blinded to the intervention allocation. Data were analysed using a non-inferiority test. Group A's non-inferiority would be accepted if the lower limit of the 95 % confidence interval (CI) for the difference in the mean number of arrested decayed surfaces (ds) was greater than -0.5. RESULTS: At baseline, 1,070 children were recruited, and 535 children were assigned to each group. After 30 months, the mean arrested ds in Groups A (n = 447) and B (n = 433) were 3.7 ± 3.6 and 3.6 ± 3.7, respectively (p = 0.694). The difference in the mean arrested ds between the two groups was 0.088 (95 % CI: -0.351 to 0.526). CONCLUSION: Semi-annual application of 25 % AgNO3 followed by 5 % NaF is at least as effective as the semi-annual application of 38 % SDF in arresting ECC. CLINICAL SIGNIFICANCE: Silver and fluoride products are effective in arresting caries. As a simple, non-invasive, and inexpensive strategy, it can be used in young children, elderly adults, and people with special needs.

The Oral Health Status of Chinese Elderly People with and without Dementia: A Cross-Sectional Study.

OBJECTIVE: The objective of this study was to compare the caries, periodontal status, and toothbrushing practices of Chinese elderly people with and without dementia. METHODS: This cross-sectional study recruited Chinese people aged 65 years or over attending daycare centers in Hong Kong. The participants' dementia status was identified from their medical record. Their demographic information and toothbrushing practices were obtained through a questionnaire survey. Caries experience, periodontal status, and oral hygiene were measured using the Decayed, Missing, and Filled Teeth (DMFT) Index, Community Periodontal Index, and Visible Plaque Index (VPI), respectively. The case matching process, using the propensity score, was conducted to match the participants in dementia and nondementia groups. The chi-square test and t-test were conducted for analysis. RESULTS: A total of 341 elderly people participated in this study. After case matching by gender and age, 129 participants with dementia were matched with 99 participants without dementia. The mean age and mean DMFT of the dementia group versus the nondementia group were 80.9 ± 7.5 vs. 79.4 ± 6.7 (p = 0.428) and 22.5 ± 7.9 vs. 19.2 ± 9.3 (p = 0.041), respectively. There was no significant difference of periodontal status observed. The VPI of dementia and nondementia groups were 77% and 63%, respectively (p = 0.027). Though they had no difference in frequency of toothbrushing, more dementia participants encountered difficulties in toothbrushing than those without dementia (57% vs. 8%, p < 0.001). CONCLUSION: Compared with elderly people without dementia, Chinese elderly people with dementia had more caries experience and poorer oral hygiene in Hong Kong. They were more likely to have difficulty in performing toothbrushing.

Oral health-related quality of life and caries experience of Hong Kong preschool children.

OBJECTIVE: This study aimed to investigate the association between oral health-related quality of life (OHRQoL) and caries experience of Hong Kong preschool children. METHODS: Parents or primary caregivers of Hong Kong preschool children were invited to complete a self-administered dental health questionnaire. The study children were examined in their classrooms. The decayed, missing and filled primary teeth (dmft) index was used for documenting the caries status. The questionnaire included the Chinese Early Childhood Oral Health Impact Scale (ECOHIS) and collected sociodemographic information on the parents and children. Logistic regression analysis was used to determine the association between OHRQoL and caries experience of preschool children. RESULTS: A total of 434 preschool children were invited to participate in the study; 336 (77.4%) received a dental examination and returned a parental questionnaire. The mean (SD) age of the study children was 4.7 (0.3) years. An OHRQoL impact (ECOHIS score of >0) for at least one item was reported by 236 (70.2%) parents/caregivers of the children included in the study. The overall mean (SD) ECOHIS score was 5.8 (6.2). A caries prevalence (dmft > 0) of 36.9% and a mean (SD) dmft score of 1.7 (3.2) were calculated for the study children. In the final logistic regression model, children with a higher dmft score had a significantly higher chance of having a poorer OHRQoL (OR = 1.20, 95% CI: 1.07-1.35, P = 0.002), whereas children's sex, parent's education levels and the respondent's relationship to the child were not associated with OHRQoL (P > 0.05). CONCLUSION: Caries experience is associated with lower OHRQoL of Hong Kong preschool children.

Utilization of a Mobile Dental Vehicle for Oral Healthcare in Rural Areas.

Oral diseases remain one of the major global public health challenges, and the worldwide urban⁻rural disparities in oral health are significant. Residents in rural areas generally suffer from a higher prevalence and severity of dental caries and periodontal disease, yet they face numerous difficulties and barriers in accessing oral healthcare. Conventional strategies, such as building of dental clinics or, hospitals, or the provision of outreach services by using disposable materials, are neither practical nor effective in rural settings. Mobile dental vehicles (MDVs) have been proposed as an alternative strategy to supplement the traditional oral healthcare in many regions. They have usually been utilized in school-based oral health programs, providing dental care to the homeless or migrants, and screening programs for the population for various oral diseases. Due to their high mobility, MDVs are particularly valuable for the underserved populations living in rural areas. The advance of dental devices enables MDVs to be operated in a self-sufficient manner. This allows the MDV to function almost as well as a conventional dental clinic, providing a variety of dental treatments, including scaling, restoration, and oral surgery. This article discusses the use of MDVs as a solution to urban⁻rural inequality in receiving oral healthcare.

Medical Model in Caries Management.

The current mode of dental caries management mainly operates through irreversible and symptomatic treatment by means of drilling and filling, while caries prevention is largely overlooked or omitted. Focus should be redirected through a medical model towards elimination of the disease through tackling its causes and risk factors to address current and future caries initiation. Caries is the demineralisation of dental hard tissues by bacterial acids when periodically exposed to fermentable carbohydrates. The medical model of caries management is a philosophy that steers sustainable caries management through controlling bacterial infection, a reduction of risk levels, remineralisation of teeth and long-term follow-up. Its goal is to prevent new and recurrent caries, arrest ongoing caries processes by alteration of the cariogenic environment, and support the healing of remineralisable enamel and dentine. The mechanism involves dietary counselling and plaque control, placement of dental sealants, administration of fluoride agents and chemotherapeutic medications and use of chewing gum. This paradigm shift from a surgical to a medical model aims to pursue the ultimate intention of maintaining a caries-free dentition and is anticipated to promote true oral health-related quality of life. The objective of this paper is to discuss the medical model of caries management.

Early childhood caries and oral health care of Hong Kong preschool children.

Surveys have shown that the prevalence of early childhood caries (ECC) among 5-year-old children decreased from 63% in 1993 to 55% in 2017. Caries experience was unevenly distributed; 81% of the caries lesions were found in 26% of the children. Risk factors, including oral hygiene practice behaviors, sugar consumption, parental oral health-related knowledge, and sociodemographic backgrounds, were significantly related to ECC. Oral health promotion aimed at managing the burden of ECC has been implemented. Water fluoridation was launched in 1961, and the fluoride concentration has been adjusted to 0.5 ppm since 1988. It is considered an important dental public health measure in Hong Kong. The Department of Health set up the Oral Health Education Unit in 1989 to deliver oral health education to further improve the oral health of preschool children. Other nongovernmental organizations also launched short-term oral health promotion programs for preschool children. However, no significant change in the prevalence of ECC has been observed in the recent two decades. There is a necessity to revisit dental public health policies and develop effective evidence-based strategies to encourage changes in oral health-related behaviors to forestall the impending epidemic of ECC in Hong Kong.