Supplementary Material for: The 20-year trends in caries and associated determinants among adults in “post-Soviet” Lithuania: repeated cross-sectional studies

Aim. To examine the 20-year trend in dental caries and associated determinants among adults in Lithuania after the country restored its independence. Material and methods. Data from two cross-sectional national surveys included samples of 35-44-year-olds (adults) and 65-74-year-olds (early elderly). The 1997/1998 survey (first survey) recruited a stratified random sample of 570 individuals from 10 selected areas in Lithuania (response rate 52%) and the 2017/2019 survey (second survey) recruited a stratified random sample of 723 individuals from 5 biggest Lithuanian cities and one randomly selected peri-urban/rural area from each of 10 Lithuanian counties (response rate 53%). The information about the social (sex, residence, education) and behavioral (tooth brushing frequency, use of fluoridated toothpaste and last dental visit) determinants was collected via self-reports using the World Health Organization (WHO) Oral Health Questionnaire for Adults questions. Information about the fluoride level in the drinking water was retrieved from the water suppliers. Dental caries was recorded at the surface level following the WHO criteria by two calibrated examiners, one at each of the national surveys. Bivariate and multivariate analyses were used. Results. According to multivariable negative binomial regression analysis, in adults, a 67% lower DS scores (IRR 0.33, 95%CI 0.26-0.42) and in early elderly a 47% lower DS scores (IRR 0.53, 95%CI 0.38-0.74) were observed in the second survey. Adults in the second survey (vs. first survey) had 62% lower MT scores (IRR 0.38, 95%CI 0.32-0.46), and the early elderly had 19% lower MT scores (IRR 0.81, 95%CI 0.72-0.92). Adults in the second survey had a 21% lower DMFT scores (IRR 0.79, 95%CI 0.73-0.85). The changes in behavioral determinants were observed over the 20-year period. Conclusion. An improvement in dental health during the 20-year period, mainly related to reduction in untreated caries and missing teeth, was observed in adults and early elderly. However, early elderly still had high numbers of missing teeth. The decrease in total caries experience during the 20 years was significant only in adults. Our findings support an urgent need to design and implement national oral health promotion and prevention programs with increased focus on oral self-care and fluoridated toothpaste use.

研究目的：探讨立陶宛恢复独立后20年间成年人群龋齿及其相关影响因素的变化趋势。
材料与方法：本研究纳入两项全国性横断面调查数据，研究对象为35~44岁成年人及65~74岁早期老年人群。1997/1998年首轮调查从立陶宛10个选定区域采用分层随机抽样方法招募570名受试者，应答率为52%；2017/2019年第二轮调查则从立陶宛5个最大城市，以及10个立陶宛县各随机选取1个城郊/农村区域，共招募723名受试者，应答率为53%。研究通过《世界卫生组织（World Health Organization, WHO）成人口腔健康调查问卷》收集社会人口学因素（性别、居住地、受教育程度）与行为因素（刷牙频率、含氟牙膏使用情况、末次牙科就诊经历）的自我报告数据。饮用水氟化物水平数据由当地供水机构提供。两项全国性调查均由2名经过校准的检查人员分别完成，每项调查各配备1名检查者，按照WHO标准以牙面为单位记录龋齿患病情况。数据分析采用双变量及多变量统计分析方法。
研究结果：多变量负二项回归分析结果显示，与首轮调查相比，第二轮调查的成年人群龋面数（DS）得分降低67%（发病率比IRR=0.33，95%置信区间CI：0.26~0.42），早期老年人群龋面数得分降低47%（IRR=0.53，95%CI：0.38~0.74）。成年人群的失牙数（MT）得分较首轮调查降低62%（IRR=0.38，95%CI：0.32~0.46），早期老年人群该指标降低19%（IRR=0.81，95%CI：0.72~0.92）。成年人群的龋失补牙数（DMFT）得分降低21%（IRR=0.79，95%CI：0.73~0.85）。20年间研究对象的行为影响因素亦发生显著变化。
研究结论：20年间立陶宛成年及早期老年人群的口腔健康状况均得到改善，主要体现为未治疗龋齿及缺失牙数量减少。但早期老年人群的缺失牙数量仍处于较高水平。20年间总龋病患病经历的降低仅在成年人群中具有统计学显著性。本研究结果提示，亟需制定并实施全国性口腔健康促进与预防项目，重点加强口腔自我护理指导及含氟牙膏的推广使用。