title: Oral Health, Nudge Theory and Migrants
Creators: name: Banihashem Rad, Seyed Ahmad
Publisher: name: Universität Bern
Year: 2025
Subjects: subject: 610 Medicine &amp; health

description: Background and Aims: Oral health significantly impacts overall well-being but remains one of the most neglected aspects of health, especially among marginalized populations. This PhD thesis had three primary aims: first, to assess the global prevalence of oral diseases among immigrants and refugees (Publications 1 and 2); second, to explore the potential applications of Nudge theory in oral health promotion (Publication 3); and third, to evaluate the effectiveness of Nudge theory-based interventions in improving oral self-care among schoolchildren with refugee and immigrant backgrounds through a field trial (Publication 4).
Methods: The first two studies (Study 1 and 2) were scoping reviews conducted following PRISMA guidelines to evaluate the global prevalence of dental caries and periodontal diseases among immigrants and refugees. Study 3 was a critical review utilizing Daly and Carnwell’s framework. The reviews used, data from specific online databases (i.e., Scopus, Embase, and PubMed). Study 4 was a quasi-experimental field trial involving 309 schoolchildren, approximately 9 years old. Interventions using motivational video clips were randomly assigned across three schools: one received messages based on Social Norms (MSN), another on messages of Fear of Negative Outcomes (MFNO), and a control group (C). Baseline plaque index (PI) and caries experience in primary and permanent dentition (dmft/DMFT) were recorded. PI was reassessed at two weeks, two months, and six months post-intervention.
Results: This thesis comprises four published studies with the main findings summarized as follows:

Publications 1 and 2: High prevalence of dental caries and gingivitis was consistently observed among immigrants and refugees, with caries rates varying from 4.6% to 98.7% and gingivitis from 5.7% to 100% across all demographic groups showing high heterogeneity in their oral health, moreover, the data showed a low level of access to dental health services for these population groups.
Publication 3: There is a dearth of studies on behavioral economics, particularly those involving reward and reminder techniques. Despite this, several successful nudge interventions in sectors such as nutrition, tobacco and alcohol cessation, and medication compliance suggest the potential for oral health to benefit from the same cognitive mechanisms as these interventions. These nudges vary significantly in effectiveness depending on the delivery method and the characteristics of the population.
Publication 4: There was a significant reduction in the mean PI across all groups at the two-week follow-up (p < 0.01). However, these improvements diminished over six months, with significant long-term benefits observed only in the MSN and MFNO groups (p < 0.01). The average decayed, missing, and filled teeth (dmft/DMFT) scores were 4.24 ± 2.11 and 1.70 ± 1.24, respectively, with Afghan children showing significantly higher dmft scores compared to Iranian children (p = 0.01). Using the Nudge theory via visual aids was more effective in promoting oral self-care than traditional Oral Health Instruction (OHI), with MSN showing better immediate effects and MFNO demonstrating more long-lasting impacts.
Conclusions: This thesis underscores the urgent need for targeted interventions to address significant oral health disparities among refugees and immigrants, highlighting the necessity for comprehensive studies in diverse socioeconomic contexts. Nudge theory emerges as a promising strategy to improve oral health behaviors, yet its long-term effectiveness requires further exploration and testing across different populations. To enhance access and outcomes in oral health care for marginalized groups, it is crucial to develop adaptive policies and strategies, to improve oral health of marginalized populations.

Publication 1: Banihashem Rad SA, Esteves Oliveira M, Maklennan A, Castiglia P, Campus G (2023). “Higher prevalence of dental caries and periodontal problems among refugees: A scoping review”. Journal of Global Health, 13:04111. DOI: 10.7189/jogh.13.04111. PMID: 37712847; PMCID: PMC10503462. 

Publication 2: Banihashem Rad SA, Esteves-Oliveira M, Maklennan A, Douglas GV, Castiglia P, Campus G (2024). “Oral health inequalities in immigrant populations worldwide: a scoping review of dental caries and periodontal disease prevalence”. BMC public health, 24(1):1968. DOI: 10.1186/s12889-024-19354-4.

 Publication 3: Kazemian A, Hoseinzadeh M, Banihashem Rad SA, Jouya A, Tahani B (2023). “Nudging oral habits; application of behavioral economics in oral health promotion: a critical review”. Frontiers in Public Health, 11:1243246. DOI: 10.3389/fpubh.2023.1243246. PMID: 38145077; PMCID: PMC10739307. 

Publication 4: Banihashem Rad SA, Esteves-Oliveira M, Kazemian A, Azami N, Khorshid M, Sohrabi A, Attaran Khorasani A, Campus G (2024). “Evaluating the Effectiveness of the Nudge Theory in Improving the Oral Self-Care of Schoolchildren with Refugee and Immigrant Backgrounds in Mashhad, Iran”. Dentistry Journal, 12(7):228. DOI: 10.3390/dj12070228. PMID: 39057015; PMCID: PMC11276547.