Oral health-related quality of life in the Myanmar population: The first national oral health survey 2016 - 2017.

OBJECTIVES: To describe the oral health-related quality of life (OHRQoL) and its potential influencing factors within the Myanmar population. METHODS: Data were from the first national oral health survey, involving 3,513 participants aged 15-18 years, 35-44 years, and 60-74 years from 21 selected townships in Myanmar. Self-administered questionnaire-based surveys, conducted from December 2016 to January 2017, included socio-demographics, behavioral factors, self-reported oral conditions (number of teeth present, teeth and gingival conditions), and inquiries regarding OHRQoL (a set of 12 questions with 5 response options) using the recommended questions from WHO Oral Health Surveys. RESULTS: The most prevalent oral health issues were difficulties in chewing (32.2%) and biting foods (30.8%). In bivariate analysis, older individuals, rural residents, and participants with higher educational levels were associated with OHRQoL. In multiple regression analysis, self-reported number of teeth, teeth and gingival conditions were strong predictors of OHRQoL in all age groups. CONCLUSION: Self-rated oral health conditions predicted quality of life due to oral problems. The development of national oral health policies and strategies is imperative to facilitate early detection of oral health problems and promote the awareness of oral health importance.

Surface nanostructures on Nb-doped SrTiO3irradiated with swift heavy ions at grazing incidence.

A single crystal of SrTiO3doped with 0.5 wt% niobium (Nb-STO) was irradiated with 200 MeV Au32+ions at grazing incidence to characterize the irradiation-induced hillock chains. Exactly the same hillock chains are observed by using atomic force microscopy (AFM) and scanning electron microscopy (SEM) to study the relation between irradiation-induced change of surface topography and corresponding material property changes. As expected, multiple hillocks as high as 5-6 nm are imaged by AFM observation in tapping mode. It is also found that the regions in between the adjacent hillocks are not depressed, and in many cases they are slightly elevated. Line-like contrasts along the ion paths are found in both AFM phase images and SEM images, indicating the formation of continuous ion tracks in addition to multiple hillocks. Validity of preexisting models for explaining the hillock chain formation is discussed based on the present results. In order to obtain new insights related to the ion track formation, cross-sectional transmission electron microscopy (TEM) observation was performed. The ion tracks in the near-surface region are found to be relatively large, whereas buried ion tracks in the deeper region are relatively small. The results suggest that recrystallization plays an important role in the formation of small ion tracks in the deep region, whereas formation of large ion tracks in the near-surface region is likely due to the absence of recrystallization. TEM images also show shape deformation of ion tracks in the near-surface region, suggesting that material transport towards the surface is the reason for the absence of recrystallization.

Colchicine protects against cartilage degeneration by inhibiting MMP13 expression via PLC-γ1 phosphorylation.

OBJECTIVE: Low molecular weight compounds that reduce the expression of MMP13 at the mRNA level might serve as disease-modifying osteoarthritis (OA) drugs (DMOADs). The objective of this study was to identify a candidate DMOAD that targets MMP13 expression. DESIGN: High-throughput screening was performed to identify compounds that suppress inflammatory cytokine-induced MMP13 expression. Ingenuity pathway analysis (IPA) using isobaric tags for relative and absolute quantification (iTRAQ)-based proteomic analysis was conducted to identify signaling pathways related to cytokines. MMP13 expression in chondrocytes was evaluated through RT-qPCR and western blotting analyses. Additionally, 10-week-old mice were subjected to destabilization of the medial meniscus (DMM) surgery to induce OA and were sacrificed 12 weeks post-surgery for pathological examination. OA was evaluated using the OARSI scoring system. RESULTS: Colchicine was identified as a DMOAD candidate as it inhibited inflammatory cytokine-induced MMP13 expression in vitro, and the colchicine-administered mice with DMM presented significantly lower OARSI scores (adjusted P: 0.0242, mean difference: 1.6, 95% confidence interval (CI) of difference: 0.1651-3.035) and significantly lower synovial membrane inflammation scores (adjusted P: 0.0243, mean difference: 0.6, 95% CI of difference: 0.06158-1.138) than mice with DMM. IPA further revealed that components of the Rho signaling pathways are regulated by cytokines and colchicine. IL-1ß and TNF-α activate RAC1 and SRC signals, respectively, leading to the phosphorylation of PLC-γ1 and synergistic induction of MMP13 expression. Most notably, colchicine abrogates inflammatory cytokine-induced phosphorylation of PLC-γ1, leading to the induction of MMP13 expression. CONCLUSIONS: Colchicine is a potential DMOAD candidate that inhibits MMP13 expression and consequent cartilage degradation by disrupting the SRC/RAC1-phospho-PLCγ1-Ca2+ signaling pathway.

Heparan sulfate deficiency leads to hypertrophic chondrocytes by increasing bone morphogenetic protein signaling.

OBJECTIVE: Exostosin-1 (EXT1) and EXT2 are the major genetic etiologies of multiple hereditary exostoses and are essential for heparan sulfate (HS) biosynthesis. Previous studies investigating HS in several mouse models of multiple hereditary exostoses have reported that aberrant bone morphogenetic protein (BMP) signaling promotes osteochondroma formation in Ext1-deficient mice. This study examined the mechanism underlying the effects of HS deficiency on BMP/Smad signaling in articular cartilage in a cartilage-specific Ext-/- mouse model. METHOD: We generated mice with a conditional Ext1 knockout in cartilage tissue (Ext1-cKO mice) using Prg4-Cre transgenic mice. Structural cartilage alterations were histologically evaluated and phospho-Smad1/5/9 (pSmad1/5/9) expression in mouse chondrocytes was analyzed. The effect of pharmacological intervention of BMP signaling using a specific inhibitor was assessed in the articular cartilage of Ext1-cKO mice. RESULTS: Hypertrophic chondrocytes were significantly more abundant (P = 0.021) and cartilage thickness was greater in Ext1-cKO mice at 3 months postnatal than in control littermates (P = 0.036 for femur; and P < 0.001 for tibia). However, osteoarthritis did not spontaneously occur before the 1-year follow-up. matrix metalloproteinase (MMP)-13 and adamalysin-like metalloproteinases with thrombospondin motifs(ADAMTS)-5 were upregulated in hypertrophic chondrocytes of transgenic mice. Immunostaining and western blotting revealed that pSmad1/5/9-positive chondrocytes were more abundant in the articular cartilage of Ext1-cKO mice than in control littermates. Furthermore, the BMP inhibitor significantly decreased the number of hypertrophic chondrocytes in Ext1-cKO mice (P = 0.007). CONCLUSIONS: HS deficiency in articular chondrocytes causes chondrocyte hypertrophy, wherein upregulated BMP/Smad signaling partially contributes to this phenotype. HS might play an important role in maintaining the cartilaginous matrix by regulating BMP signaling.

An analysis of osteoporosis in patients with hereditary multiple exostoses.

We analyzed osteoporosis in 20 HME patients. According to the T-score of BMD, 30% and 67.5% of the patients fell in the range of osteopenia in the lumbar spine and femoral neck. Our results indicate HME patients have low bone mass. They do not have abnormal bone metabolism. INTRODUCTION: There are few reports of osteoporosis in hereditary multiple exostoses (HME) patients. Therefore, the purpose of this study was to analyze osteoporosis in HME patients. METHODS: This retrospective cohort study included 20 patients diagnosed with HME. Patients underwent bone mineral density (BMD) measurement of the lumbar spine (n = 20) and femoral neck (n = 40). Bone metabolic parameters, including serum osteocalcin and urinary cross-linked N-telopeptide of type 1 collagen (NTx), were analyzed in all subjects. EXT1 and EXT2 genes were sequenced using genomic DNA. We also examined the correlation between genotype and BMD Z-score and T-score. RESULTS: The mean BMD values of the lumbar spine were 1.085 ± 0.116 g/cm2 (n = 11) in male and 1.108 ± 0.088 g/cm2 (n = 9) in female. The mean BMD values of the femoral neck area were 0.759 ± 0.125 g/cm2 (n = 22) in male and 0.749 ± 0.115 g/cm2 (n = 18) in female. Z-score of most HME patients show < 0, indicating that these patients tend to have low bone mass compared with the age-matched population. According to the T-score of BMD, 30% (6 of 20) and 67.5% (27 of 40) of the patients fell in the range of osteopenia in the lumbar spine and femoral neck areas, respectively. Serum osteocalcin and urinary NTx were in the normal range in most patients. There was no significant correlation between genotypes and Z-score. CONCLUSION: HME patients have low bone mass, especially in the femoral neck area. They do not have abnormal bone metabolism, and there was no correlation between genotypes and Z-score.

The relationship between sucrose intake in coffee or tea, and root or coronal caries in an elderly Japanese population.

OBJECTIVES: Few studies have examined the effect of sucrose intake in coffee or tea (SCT) on dental caries, especially root caries, in elderly people. The purpose of the present study was to examine the associations between SCT and the prevalence of root or coronal caries in community-dwelling elderly Japanese. METHODS: Participants were 370 elders aged 75 years from a larger cohort study of elders in Niigata City, Japan. Dietary habits during the preceding month were assessed with a validated brief self-administered diet history questionnaire (BDHQ). The caries examination was conducted using mirror and ball-pointed periodontal probes under artificial light. Poisson regression analysis was performed to analyze the prevalence-rate ratios (PRRs) between SCT and the root or coronal caries. The number of root or coronal caries was selected as the dependent variable for the analysis. Then, SCT (tertiles labeled low, medium and high) and other 4 variables were selected as independent variables. RESULTS: The PRRs between the number of root caries lesions and SCT were signifi cantly higher in the second (medium intake, 1.38, p ⟨ 0.001) and third tertiles (high intake, 2.07, p ⟨ 0.001). Similar tendencies were seen for the number of coronal caries lesions (PRRs in the second and third tertiles 1.74 and 2.46, respectively, both p ⟨ 0.001). CONCLUSION: A significant positive relationship was observed between sucrose in coffee and tea and the number of coronal or root caries lesions in community-dwelling elderly Japanese.

Current insights into the role of human ß-defensins in atopic dermatitis.

Anti-microbial peptides or host defence peptides are small molecules that display both anti-microbial activities and complex immunomodulatory functions to protect against various diseases. Among these peptides, the human ß-defensins (hBDs) are localized primarily in epithelial surfaces, including those of the skin, where they contribute to protective barriers. In atopic dermatitis skin lesions, altered skin barrier and immune dysregulation are believed to be responsible for reduced hBD synthesis. Impaired hBD expression in the skin is reportedly the leading cause of increased susceptibility to bacterial and viral infection in patients with atopic dermatitis. Although hBDs have considerable beneficial effects as anti-microbial agents and immunomodulators and may ameliorate atopic dermatitis clinically, recent evidence has also suggested the negative effects of hBDs in atopic dermatitis development. In the current review, we provide an overview of the regulation of hBDs and their role in the pathogenesis of atopic dermatitis. The efforts to utilize these molecules in clinical applications are also described.

Oral administration of milk-derived phospholipids inhibits penetration of cutaneous nerve fibres into epidermis in a mouse model of acute dry skin.

The density of intraepidermal nerve fibres has been shown to be higher in itchy dry skin than in healthy skin, suggesting that epidermal hyperinnervation is at least partly involved in peripheral itch sensitization. We investigated whether oral administration of milk-derived phospholipids (MPLs) would inhibit epidermal hyperinnervation in a mouse model of dry skin. We found that the number of intraepidermal nerve fibres was significantly lower in the MPL group than in the control group. Expression of nerve growth factor (NGF) levels in the epidermis was significantly decreased by oral administration of MPLs, whereas expression of semaphorin (Sema)3A, a nerve repulsion factor, was increased in the MPL group. These results suggest that dietary MPLs attenuate the penetration of nerve fibres into the epidermis by reducing epidermal NGF levels and increasing Sema3A level. Thus, dietary MPLs may have beneficial effects in the prevention and/or alleviation of dry skin-induced itch by reducing intraepidermal nerve fibre density.

Relationship of physical activity with physical function and health-related quality of life in patients having undergone allogeneic haematopoietic stem-cell transplantation.

In this study, we investigated the differences in physical activity before and after transplantation, and the relationship between physical activity and physical function and health-related quality of life (QOL) in 30 patients who underwent allogeneic haematopoietic stem cell transplantation (allo-HSCT). Duration and intensity of physical activity were quantified using a three-dimensional accelerometer. Physical function was quantified by handgrip and knee-extensor strength, with the 6-minute walk test (6MWT) used as a measure of exercise capacity. Health-related QOL was assessed using the 36-item Short-Form Health Survey. The proportion of daily activities performed at an intensity >3.0 metabolic equivalents (METs) increased significantly after allo-HSCT (p < .05). Daily activity time performed at an intensity of 1.6-2.9 METs significantly correlated only with left knee strength (p < .05). In contrast, the total number of daily steps and the proportion of activity performed at 1.6-2.9 METs and >3.0 METs were positively correlated with the 6MWT (p < .05). Additionally, physical functioning and general health subscales in health-related QOL positively correlated with daily activities performed at >3.0 METs (p < .05). Physical activity was associated with 6MWT and health-related QOL. These findings have implications for rehabilitation planning for patients undergoing allo-HSCT.

The association between dentition status and sarcopenia in Japanese adults aged ≥75 years.

Sarcopenia is an age-related loss of muscle mass and muscle strength or physical performance. There are limited data on the association between oral health and sarcopenia. To test the hypothesis that impaired dentition status was associated with sarcopenia, we conducted a cross-sectional study. A total of 272 community-dwelling Japanese adults aged ≥75 years for whom data were available from comprehensive health examinations conducted in 2015 were included in this study. During dental examination, the number of natural teeth and occluding pairs of natural teeth was counted. In denture wearers, the fit of the removable dentures was also evaluated. The criteria proposed by the Asian Working Group for Sarcopenia were used to define sarcopenia. A multivariable logistic regression model was used to evaluate the association between dentition status and the presence of sarcopenia. The prevalence of sarcopenia was 25·7% (70/272). Compared to individuals with ≥10 occluding pairs of natural teeth, those with no occluding pairs of natural teeth had significantly higher risk of having sarcopenia (adjusted odds ratio, 3·37; 95% confidence interval, 1·07-10·61), after adjusting for possible confounders. In addition, compared to individuals with well-fitting dentures, those with ill-fitting dentures had significantly higher risk of having sarcopenia (adjusted odds ratio, 5·07; 95% confidence interval, 1·59-16·19). Our findings suggest that impaired dentition status is significantly associated with sarcopenia among community-dwelling Japanese adults aged ≥75 years. Future longitudinal studies with larger, more diverse populations are necessary to validate our findings.

Geographical variation in the skeletal morphology of red jungle fowl.

1. The skulls and postcranial skeletons of the red jungle fowl (Gallus gallus) were compared osteometrically between the populations from North and South Vietnam, North and Central Laos and Southeast Bangladesh. The populations include the three subspecies of G. g. spadiceus, G. g. gallus and G. g. murghi and were sampled to reveal the geographical morphological variations among populations in G. gallus. 2. The morphometric characteristics of subspecies murghi could be clearly distinguished from those of the other subspecies using a canonical discriminant analysis. However, the size and shape of the skull of the gallus population from South Vietnam were not statistically different from that of the subspecies spadiceus from North Laos. The canonical discriminant scores also clearly indicated that there were morphological similarities in the skulls of the populations from North Laos and South Vietnam. 3. From the results, therefore, it is concluded that red jungle fowls do not exhibit high levels of osteometric variation between geographical localities at least within the Indochinese Peninsula. 4. This contrasts with previous studies which have described these subspecies as having various external morphological differences and have argued that zoogeographical barriers exist between the north and south areas of the Indochinese Peninsula.

The role of human ß-defensins in allergic diseases.

Antimicrobial peptides (AMPs), also referred to as host defence peptides (HDPs), comprise a large family of small molecules broadly distributed throughout the animal and plant kingdom, historically serving as natural antibiotics. In mammals, there are two major families of AMPs/HDPs, the defensins and the cathelicidins. These peptides have evolved to protect against a wide range of infections from bacteria, viruses, fungi and some parasites. However, in addition to their broad-spectrum killing activities, AMPs/HDPs also possess various biological functions. They activate a variety of cell types, such as keratinocytes, airway epithelial cells and mast cells, among others, and regulate cytokine/chemokine production, cell migration, proliferation, differentiation, angiogenesis, the wound healing process and maintenance of the skin barrier function. Recently, it has become clear that alterations in the level of AMPs/HDPs are associated with the initiation and development of various inflammatory and allergic diseases. In this review, we will discuss the regulation and functions of human ß-defensins and outline the current evidence supporting the role of these peptides in the pathogenesis of allergic diseases, including atopic dermatitis, allergic rhinitis, asthma and chronic rhinosinusitis. Understanding the functions and mechanisms of human ß-defensins may aid in the development of novel therapeutic strategies for allergic diseases.

Impact of B-type natriuretic peptide (BNP) on development of atrial fibrillation in people with Type 2 diabetes.

AIMS: To examine if a simple biomarker can identify people with diabetes who are at high risk of atrial fibrillation. METHODS: A retrospective cohort study was conducted at a single centre in people with Type 2 diabetes referred to our department between January 2000 and December 2007. In 517 consecutive people without any history, signs or symptoms of atrial fibrillation at baseline, the association between baseline B-type natriuretic peptide level and future atrial fibrillation incidence was examined, with adjustments for other potentially confounding factors. RESULTS: A total of 28 people were diagnosed with new-onset atrial fibrillation during a median 6-year follow-up. When people were categorized into three groups according to B-type natriuretic peptide clinical thresholds (20 and 100 pg/ml), hazard ratios for the development of atrial fibrillation in the middle and highest B-type natriuretic peptide groups were 2.8 and 9.4, respectively, compared with the lowest B-type natriuretic peptide group. Time-dependent receiver-operating curve analysis identified a threshold for B-type natriuretic peptide to detect atrial fibrillation development of 52.8 pg/ml (sensitivity 75.2%, specificity 68.8%). The B-type natriuretic peptide predictive value was independent of and similar to that of left atrial size and ventricular dimension. CONCLUSION: In people with Type 2 diabetes, high baseline B-type natriuretic peptide levels were significantly associated with future atrial fibrillation development.

Feeding hydroalcoholic extract powder of Lepidium meyenii (maca) increases serum testosterone concentration and enhances steroidogenic ability of Leydig cells in male rats.

Although Lepidium meyenii (maca), a plant growing in Peru's central Andes, has been traditionally used for enhancing fertility and reproductive performance in domestic animals and human beings, effects of maca on reproductive organs are still unclear. This study examined whether feeding the hydroalcoholic extract powder of maca for 6 weeks affects weight of the reproductive organs, serum concentrations of testosterone and luteinising hormone (LH), number and cytoplasmic area of immunohistochemically stained Leydig cells, and steroidogenesis of cultured Leydig cells in 8-week-old male rats. Feeding the extract powder increased weight of seminal vesicles, serum testosterone level and cytoplasmic area of Leydig cells when compared with controls. Weight of prostate gland, serum LH concentration and number of Leydig cells were not affected by the maca treatment. The testosterone production by Leydig cells significantly increased when cultured with 22R-hydroxycholesterol or pregnenolone and tended to increase when cultured with hCG by feeding the extract powder. The results show that feeding the hydroalcoholic extract powder of maca for 6 weeks increases serum testosterone concentration associated with seminal vesicle stimulation in male rats, and this increase in testosterone level may be related to the enhanced ability of testosterone production by Leydig cells especially in the metabolic process following cholesterol.

Longitudinal association of dentition status with dietary intake in Japanese adults aged 75 to 80 years.

Limited information is available on the temporal association between dentition status and dietary intake. The aim of this 5-year prospective cohort study was to investigate whether impaired dentition was associated with subsequent decline in dietary intake in older Japanese adults. Two hundred and eighty-six community-dwelling Japanese individuals, all aged 75 years at baseline, were included in the study. Functional tooth units (FTUs), defined as a pair of opposing natural or prosthetic teeth excluding third molars (range: 0-14), were counted on the basis of baseline dental examinations. Individuals with ≤5 FTUs were defined as having impaired dentition. Dietary intake was assessed at baseline and 5 years later, using a validated dietary questionnaire. Robust regression analyses were used to evaluate the differences in change in dietary intake between participants with and without impaired functional dentition, after adjustment for potential confounders. Sixty-one study participants (21·3 %) were defined as having impaired dentition. Overall, mean values for all estimated dietary variables (energy, nutrients and food groups) declined over time. Notably, individuals with impaired dentition demonstrated a significantly (P < 0·05) greater degree of decline in the intake of multiple nutrients (protein, sodium, potassium, calcium, vitamin A, vitamin E and dietary fibre) and food groups (vegetable and meat) than those without impaired dentition, after adjusting for potential confounders. The results of this study describe the temporal association of impaired dentition with the decline in selected nutrient and food group intake among older Japanese adults.

Tumour-suppressive function of SIRT4 in human colorectal cancer.

BACKGROUND: SIRT4, which is localised in the mitochondria, is one of the least characterised members of the sirtuin family of nicotinamide adenine dinucleotide-dependent enzymes that play key roles in multiple cellular processes such as metabolism, stress response and longevity. There are only a few studies that have characterised its function and assessed its clinical significance in human cancers. METHODS: We established colorectal cancer cell lines (SW480, HCT116, and HT29) overexpressing SIRT4 and investigated their effects on proliferation, migration and invasion, as well as E-cadherin expression, that negatively regulates tumour invasion and metastases. The associations between SIRT4 expression in colorectal cancer specimens and clinicopathological features including prognosis were assessed by immunohistochemistry. RESULTS: SIRT4 upregulated E-cadherin expression and suppressed proliferation, migration and invasion through inhibition of glutamine metabolism in colorectal cancer cells. Moreover, SIRT4 expression in colorectal cancer decreased with the progression of invasion and metastasis, and a low expression level of SIRT4 was correlated with a worse prognosis. CONCLUSIONS: SIRT4 has a tumour-suppressive function and may serve as a novel therapeutic target in colorectal cancer.

Allergen-specific basophil reactivity exhibits daily variations in seasonal allergic rhinitis.

It remains poorly understood how symptoms in allergic rhinitis are most severe during overnight or early in the morning. The circadian clock consisting of a network of several 'clock genes' including Clock drives daily rhythms in physiology. This study showed that allergen-induced surface CD203c expression on basophils in seasonal allergic rhinitis caused by Japanese cedar pollen exhibited a time-of-day-dependent variation associated with temporal variations in canonical circadian clock gene expression. We also found that bone-marrow-derived basophils (BM basophils) generated from wild-type mice exhibited a time-of-day-dependent variation in IgE-mediated IL-4 and histamine production, which was not observed in BM basophils generated from Clock-mutated mice. Therefore, allergen-specific basophil reactivity shows daily variations depending on the circadian clock activity in basophils, which could partly explain temporal symptomatic variations in allergic rhinitis. Additionally, circadian variations in CD203c expression should be considered for interpretation of this biomarker in clinical research.

Relationship between metabolic syndrome and periodontitis in 80-year-old Japanese subjects.

BACKGROUND AND OBJECTIVE: Potentially significant associations between metabolic syndrome (MetS) and periodontitis have been reported in recent studies; however, there are limited data on their association in the very old. The aim of this cross-sectional study was to investigate the association between MetS and periodontitis among 80-year-old Japanese subjects. MATERIAL AND METHODS: The subjects were 234 Japanese aged 80 years old who participated in a health and periodontal examination in June 2008 in Niigata city, Japan, and were classified into three groups: (i) severe periodontitis: having six or more interproximal sites with clinical attachment level ≥ 6 mm and three or more interproximal sites with probing pocket depth (PPD) ≥ 5 mm (not on the same tooth) (n = 19); (ii) moderate periodontitis: having six or more interproximal sites with clinical attachment level ≥ 4 mm or six or more interproximal sites with PPD ≥ 5 mm (not on the same tooth) (n = 162); and (iii) no or mild periodontitis: neither "moderate" nor "severe" periodontitis (n = 53). MetS was defined using the modified criteria of the guidelines for the diagnosis of MetS in Japan. An ordinal logistic regression model was used to evaluate the association between MetS and periodontitis. Adjustments for gender, income, education, smoking status, dental visiting patterns, brushing frequency, exercise habits and dietary energy and food intake were considered. RESULTS: Overall, 57 individuals (24.4%) were diagnosed as having MetS. MetS was associated with the presence and severity of periodontitis (crude odds ratio = 2.24, 95% confidence interval = 1.14-4.41). This association remained statistically significant after multivariate adjustments (adjusted odds ratio = 2.10, 95% confidence interval = 1.03-4.28). CONCLUSION: Our findings provide evidence of an association between MetS and periodontitis in elderly Japanese.

Long-term evaluation of the clinical effectiveness of community milk fluoridation in Bulgaria.

OBJECTIVE: To determine the clinical effectiveness of a community milk fluoridation programme. BASIC RESEARCH DESIGN: Parallel arm 5-year cohort study, with final cross-sectional comparisons between groups. PARTICIPANTS: 3-year-olds in 8 Bulgarian cities/towns entered the cohort study with random samples (n = 1,782) recruited at baseline in 2004. After 5 years in 2009 sub-samples (about 30%) of these now aged 8 were randomly selected in intervention sites for follow-up examination (n = 454); 276 controls were examined at the age 8 years. For cross-sectional comparisons, in 2004, 284 3-year-olds from control cities were baseline examined for caries, then 276 children at the age 8 years in 2009. INTERVENTIONS: In six intervention communities: 1,498 examined children received 0.5 mg F in 100 or 200 ml school milk or yogurt provided each school day; a further 180 received non-fluoridated milk. In two control communities, fluoride was not added to 284 children's school milk. MAIN OUTCOME MEASURES: Dental caries experience of primary, and permanent teeth. RESULTS: For primary teeth, caries increments were 46% (p < 0.001) and 30% (p < 0.01) lower in the fluoridated milk groups compared with non-fluoridated milk groups in the intervention and control communities, respectively. For permanent teeth those reductions were 61% and 53% (p < 0.001). The cross-sectional comparisons of 8-year-olds showed significant changes in dental caries experience over time; in children consuming fluoridated milk the level of dmfs fell by 43% (2004 and 2009) against 11% in the control group. Among children consuming fluoridated milk the DMFS fell 68% against rising 3% in the controls. CONCLUSIONS: Fluoridated milk delivered daily in schools in Bulgaria resulted in substantially lower caries development compared with children in schools receiving milk without added fluoride. The nation-wide experiences from milk fluoridation indicate that such a public health scheme can be effective to the global fight against dental caries of children.