New Cav1.2 Channelopathy with High-Functioning Autism, Affective Disorder, Severe Dental Enamel Defects, a Short QT Interval, and a Novel CACNA1C Loss-Of-Function Mutation.

Complex neuropsychiatric-cardiac syndromes can be genetically determined. For the first time, the authors present a syndromal form of short QT syndrome in a 34-year-old German male patient with extracardiac features with predominant psychiatric manifestation, namely a severe form of secondary high-functioning autism spectrum disorder (ASD), along with affective and psychotic exacerbations, and severe dental enamel defects (with rapid wearing off his teeth) due to a heterozygous loss-of-function mutation in the CACNA1C gene (NM_000719.6: c.2399A > C; p.Lys800Thr). This mutation was found only once in control databases; the mutated lysine is located in the Cav1.2 calcium channel, is highly conserved during evolution, and is predicted to affect protein function by most pathogenicity prediction algorithms. L-type Cav1.2 calcium channels are widely expressed in the brain and heart. In the case presented, electrophysiological studies revealed a prominent reduction in the current amplitude without changes in the gating behavior of the Cav1.2 channel, most likely due to a trafficking defect. Due to the demonstrated loss of function, the p.Lys800Thr variant was finally classified as pathogenic (ACMG class 4 variant) and is likely to cause a newly described Cav1.2 channelopathy.

Recessive Mutations in ACPT, Encoding Testicular Acid Phosphatase, Cause Hypoplastic Amelogenesis Imperfecta.

Amelogenesis imperfecta (AI) is a heterogeneous group of genetic disorders affecting tooth enamel. The affected enamel can be hypoplastic and/or hypomineralized. In this study, we identified ACPT (testicular acid phosphatase) biallelic mutations causing non-syndromic, generalized hypoplastic autosomal-recessive amelogenesis imperfecta (AI) in individuals from six apparently unrelated Turkish families. Families 1, 4, and 5 were affected by the homozygous ACPT mutation c.713C>T (p.Ser238Leu), family 2 by the homozygous ACPT mutation c.331C>T (p.Arg111Cys), family 3 by the homozygous ACPT mutation c.226C>T (p.Arg76Cys), and family 6 by the compound heterozygous ACPT mutations c.382G>C (p.Ala128Pro) and 397G>A (p.Glu133Lys). Analysis of the ACPT crystal structure suggests that these mutations damaged the activity of ACPT by altering the sizes and charges of key amino acid side chains, limiting accessibility of the catalytic core, and interfering with homodimerization. Immunohistochemical analysis confirmed localization of ACPT in secretory-stage ameloblasts. The study results provide evidence for the crucial function of ACPT during amelogenesis.

Dental caries and developmental defects of enamel in individuals with chronic kidney disease: Systematic review and meta-analysis.

OBJECTIVE: To evaluate studies assessing the prevalence of dental caries and developmental defects of enamel (DDE) in individuals with chronic kidney disease (CKD) in comparison with individuals without CKD. MATERIALS AND METHODS: Electronic searches were performed in PubMed, Web of Science, Scopus, Medline via Ovid, and ProQuest databases from their inception date until February 2018. Two review authors independently selected the studies, extracted data, and assessed the methodological quality. Meta-analysis was performed. RESULTS: Twenty-seven studies were included in this study. For permanent teeth, 14 studies found that individuals without CKD had higher dental caries scores than those with CKD. However, only five studies presented results with a statistically significant difference between groups. Among the studies evaluating primary teeth, five showed that individuals without CKD had higher dental caries scores than those with CKD. Five studies showed that individuals with CKD had a significantly higher prevalence of DDE than individuals without CKD. The meta-analyses showed that individuals without CKD had significantly higher scores of dental caries teeth and surfaces than individuals with CKD. For DDE, no statistical difference between groups was observed. CONCLUSIONS: Individuals with CKD present lower dental caries scores and a higher prevalence of DDE in comparison with individuals without CKD.

Developmental defects of enamel in the deciduous incisors of infants born preterm: Prospective cohort.

OBJECTIVE: Developmental defects of enamel (DDE) in preterm infants still require clarification and may favour dental caries, lower food intake and greater difficulty with weight-height gain. We evaluated factors associated with DDE in preterm infants. SUBJECTS AND METHODS: In this prospective cohort study, we monitored 54 prematurely born infants from birth to 24 months of age. Trained and calibrated dentists examined the oral cavity of these children to identify and categorize DDE. Information on perinatal variables was collected from the infants' medical records and interviews with their mothers. The data were analysed using Student's t test, a chi-squared test and Pearson's product-moment correlation coefficient. RESULTS: A total of 46.3% of the 54 children presented DDE, which was observed more frequently in the left hemiarch in children born extremely (<28 weeks of gestation) or very preterm (28 to <32 weeks; RR = 2.2; 95% CI 1.3-3.6), with very low birthweight (<1,500 g; RR = 2.0; 95% CI 1.1-3.5), who were admitted to the neonatal intensive care unit (RR = 1.3; 95% CI 1.0-1.7), and who were intubated (RR = 1.6; 95% CI 1.1-2.2). CONCLUSIONS: The high incidence of incisor enamel defects, particularly on the left side, was related to higher risk prematurity and to local trauma from intubation.

Oestrogen receptor alpha, growth hormone receptor, and developmental defect of enamel.

BACKGROUND: Oestrogen (ES) and growth hormone (GH) are hormones that may have a role in caries aetiology and developmental defects of enamel (DDE) since their receptors (ERs and GHR) are expressed during amelogenesis. AIM: To evaluate whether genetic polymorphisms in the genes that codify the ERα (ESR1) and GHR are associated with caries experience and DDE in children. DESIGN: Two hundred and sixteen children of both genders, aged 9-12 years, were examined and classified according to caries and DDE phenotype. Genomic DNA was extracted from buccal cells in saliva. Genetic polymorphisms in ERS1 (rs1884051 and rs12154178) and GHR (rs297305, rs2940913, rs2910875, and rs1509460) were genotyped using TaqMan chemistry. Data were analysed by PLINK, while the chi-square test was used to compare allele and genotype distributions (alpha of 5%). RESULTS: A total of 131 children (60.7%) had caries experience, and 43 (19.9%) presented DDE. Genotype and allele distributions were not associated with caries experience (P > 0.05). Genotype and allele distributions between DDE, affected and unaffected, were associated with the polymorphism rs12154178 in ESR1 (P = 0.01 and P = 0.001, respectively) and with the polymorphism rs1509460 in GHR (P = 0.05 and P = 0.02, respectively). CONCLUSIONS: Genetic polymorphisms in ERS1 (rs12154178) and GHR (rs1509460) are associated with DDE.

A long-term clinical study on individuals with amelogenesis imperfecta.

BACKGROUND: The aims of this study are to present sociodemographic and familial characteristics, clinical and systemic findings, dental treatment needs, and concomitant dental anomalies in patients with amelogenesis imperfecta (AI) and to evaluate time-varying conditions in these long-term follow-up patients. MATERIALS AND METHODS: Records of patients with AI who were examined in the Department of Pediatric Dentistry between 1999 and 2017 were reviewed. Information about sociodemographic characteristics, history of AI and consanguinity in family, systemic conditions, reasons for referral to the clinic, oral hygiene habits and gingival health, occlusion findings, and performed treatments were gathered. Dental anomalies in radiographs were also evaluated. Baseline and final situations of the patients were assessed. Statistical analyses were performed. RESULTS: Of 75 patients aged 3-15 years with follow-ups up to 12 years, 34 had AI in their families and 15 were born from consanguineous marriages. Nephrocalcinosis has been observed in 5 patients. Main reasons for referral to the clinic were related to esthetic and hypersensitivity concerns. Twenty-two patients had gingivitis, and during follow-up process, gingival problems could not be completely prevented due to poor oral hygiene habits. Vertical dimension loss, open-bite, and cross-bite were seen in 16, 15, and 10 patients, respectively. Of the patients, 63% experienced restorative, 33% stainless steel crown, 17% endodontic, 8% prosthetic treatments, and 24% had retreatment needs. Concomitant dental anomalies were dens invaginatus, taurodontism, ectopic eruption, delayed eruption, hypodontia, and pulpal calcification. CONCLUSION: Early diagnosis and interventions considering the time-varying conditions with long-term follow-ups provide significant improvements in clinical maintenance of patients with AI.

Enamel and dental anomalies in latent-transforming growth factor beta-binding protein 3 mutant mice.

Latent-transforming growth factor beta-binding protein 3 (LTBP-3) is important for craniofacial morphogenesis and hard tissue mineralization, as it is essential for activation of transforming growth factor-ß (TGF-ß). To investigate the role of LTBP-3 in tooth formation we performed micro-computed tomography (micro-CT), histology, and scanning electron microscopy analyses of adult Ltbp3-/- mice. The Ltbp3-/- mutants presented with unique craniofacial malformations and reductions in enamel formation that began at the matrix formation stage. Organization of maturation-stage ameloblasts was severely disrupted. The lateral side of the incisor was affected most. Reduced enamel mineralization, modification of the enamel prism pattern, and enamel nodules were observed throughout the incisors, as revealed by scanning electron microscopy. Molar roots had internal irregular bulbous-like formations. The cementum thickness was reduced, and microscopic dentinal tubules showed minor nanostructural changes. Thus, LTBP-3 is required for ameloblast differentiation and for the formation of decussating enamel prisms, to prevent enamel nodule formation, and for proper root morphogenesis. Also, and consistent with the role of TGF-ß signaling during mineralization, almost all craniofacial bone components were affected in Ltbp3-/- mice, especially those involving the upper jaw and snout. This mouse model demonstrates phenotypic overlap with Verloes Bourguignon syndrome, also caused by mutation of LTBP3, which is hallmarked by craniofacial anomalies and amelogenesis imperfecta phenotypes.

Parenteral nutrition in childhood and consequences for dentition and gingivae.

AIM: Assessment of dentition in children under parenteral nutrition, risk factors for caries, and dental developmental abnormalities. MATERIALS AND METHODS: The study involved 63 patients (aged 2.25-16.6 years), i.e. 32 subjects receiving parenteral nutrition for a mean period of 5.6±2.94 years, and 31 healthy control subjects. Oral hygiene (OHI-S, PL-I), gingival (GI), and dentition status (caries, DMFT/dmft, enamel defects, shape alterations), frequency of oral meals and frequency of cariogenic snacks consumption were evaluated. Medical records provided information on parenteral meals per week, age parenteral nutrition started, birth body mass, Apgar score, weight deficiency, and antibiotic therapy until aged 1 year. The Mann-Whitney test, chi-squared test, and Spearman rank correlation coefficient were used (p≤0.05). RESULTS: Dental developmental abnormalities occurred more often in PN subjects (71.87% vs. 25.80%). The prevalence of caries in PN (56.25% vs. 90.32%) and dmft (2.00±3.30 vs. 4.21±3.33) and DMFT (2.47±4.08 vs. 3.33±3.50) were lower. Positive caries Spearman's rank correlation coefficients: frequency of oral meals and frequency of cariogenic snacks consumption, and GI. Negative correlation coefficients: low birth body mass, antibiotic therapy, and low body mass in the first year of life. Positive dental developmental abnormality Spearman's coefficients: low birth body mass, Apgar score < 7, parenteral nutrition duration, low body mass and antibiotic therapy in the first year of life. Beta- lactam, aminoglycoside, glycopeptide and nitroimidazole treatments were related to enamel hypoplasia. CONCLUSION: Parenteral nutrition in childhood is related to the risk of dental developmental abnormalities, promoted by malnutrition and antibiotic therapy in infancy. Limiting the number of meals and cariogenic snacks, and most probably administration of antibiotics, decreases the risk of caries.

Developmental defects of enamel and caries in primary teeth.

Data sourcesPubMed, Web of Knowledge, Scopus and Scielo.Study selectionTwo reviewers identified studies supervised by a third. Observational studies which investigated the association between developmental defects of enamel and dental caries in the primary dentition, which were assessed by clinical examination and published in English, Spanish or Portuguese.Data extraction and synthesisQuality of research was assessed using the critical appraisal checklist from the Joanna Briggs Institute. Meta-analysis was conducted using crude and adjusted association measures (relative risk and odds ratio) with 95% confidence intervals. Combined results were presented as pooled odds ratio, and where necessary were estimated using fixed and random effect models. If heterogeneity was encountered in results, a random effect model was used. Bias was assessed using a funnel plot and the Egger test.ResultsEighteen studies were included in the systematic review and sixteen in meta-analysis; two out of the 16 were cohort studies, the rest being cross-sectional. Twelve of the studies included were conducted in low-income countries. The Egger test showed a degree of bias in some of the studies included. The authors found children with diffuse opacities or hypoplasia had higher odds of having dental caries (OR 1.42, 95% CI; 1.15-1.76; OR 4.29% CI 2.24-8.15), however the presence of demarcated opacities did not show higher odds of caries (OR 2.62, 95% CI 0.85-8.12).ConclusionsThe findings demonstrated an association between developmental defects of enamel and dental caries in the primary dentition. A preventive approach to dental caries and attention to children with enamel defects appears as a useful health promotion and public health strategy. At the individual level, clinicians should be aware that children with enamel defects could require more frequent visits to the dental office in order to reduce the risk of dental caries.

Higher Fluorosis Severity Makes Enamel Less Resistant to Demineralization.

Fluorotic teeth could either be more resistant or more susceptible to the caries process than sound ones due to their higher enamel fluoride concentration and higher porosity (subsurface hypomineralization), respectively; however, there is no consensus on this subject. In this study, a total of 49 human unerupted third molars presenting Thylstrup and Fejerskov (TF) fluorosis scores 0-4 were used. Two enamel slabs were obtained from each tooth. The rest of the tooth crown was powdered, and the enamel was separated from the dentine. In purified powdered enamel, the calcium (Ca), inorganic phosphate (Pi), and fluoride (F) concentrations were determined. The F concentration gradient throughout the enamel and in the enamel volume was determined in one slab. The other enamel slab was isolated with acid-resistant varnish, subjecting the exposed enamel surface half to a pH-cycling model to evaluate its demineralization resistance and to calculate the demineralization area. The nonexposed surface was used to determine the natural hypomineralization area found in fluorotic enamel and normalize the demineralization data. The hypomineralization and demineralization areas were assessed by cross-sectional microhardness. For statistical analyses, the data for TF1 and 2, and for TF3 and 4 were pooled. Concentrations of powered enamel Ca and Pi were not significantly different (p > 0.05) among groups TF0, TF1-2 and TF3-4, but a higher F concentration was found in fluorotic enamel (p < 0.05). Highly fluorotic teeth (TF3-4) presented a greater hypomineralization subsurface area and demonstrated lower demineralization resistance than sound enamel (p < 0.05). The findings suggest that a higher severity of fluorosis makes enamel less resistant to the caries process due to its greater subsurface mineral area exposed to demineralization and deeper acid diffusion through the enamel.

On the Etiology of Molar-Incisor Hypomineralization.

Molar-incisor hypomineralization (MIH) is a condition that is defined based on its peculiar clinical presentation. Reports on the etiology of the condition and possible risk factors are inconclusive and the original suggestion that MIH is an idiopathic condition is often cited. Our group was the first to suggest MIH has a genetic component that involves genetic variation in genes expressed during dental enamel formation. In this report, we provide a rationale to explain the preferential affection of molars and incisors. We suggest that MIH is a genetic condition based on its prevalence, which varies depending on the geographic location, and the evidence that on occasion second primary molars, permanent canines, and premolars can show signs of hypomineralization of enamel when molars and incisors are affected.

Caries prevalence and enamel defects in 5- and 10-year-old children with cleft lip and/or palate: A case-control study.

OBJECTIVE: To determine the prevalence of dental caries and enamel defects in 5- and 10-year-old Swedish children with cleft lip and/or palate (CL(P)) in comparison to non-cleft controls. MATERIALS AND METHODS: The study group consisted of 139 children with CL(P) (80 subjects aged 5 years and 59 aged 10 years) and 313 age-matched non-cleft controls. All children were examined by one of two calibrated examiners. Caries was scored according to the International Caries Detection and Assessment System (ICDAS-II) and enamel defects as presence and frequency of hypoplasia and hypomineralization. RESULTS: The caries prevalence among the 5-year-old CL(P) children and the non-cleft controls was 36% and 18%, respectively (p < 0.05). The CL(P) children had higher caries frequency (initial and cavitated lesions) in the primary dentition than their controls (1.2 vs 0.9; p < 0.05). A significantly higher prevalence of enamel defects was found in CL(P) children of both age groups and anterior permanent teeth were most commonly affected. CONCLUSIONS: Preschool children with cleft lip and/or palate seem to have more caries in the primary dentition than age-matched non-cleft controls. Enamel defects were more common in CL(P) children in both age groups.

Oral health-related quality-of-life among children in Swedish dental care: The impact from malocclusions or orthodontic treatment need.

OBJECTIVES: To describe oral health-related quality-of-life (OHRQoL) and the impact of malocclusions or orthodontic treatment need in a cohort of children in Swedish dental care, using the Swedish version of the Child Perceptions Questionnaire-Impact Short Form (CPQ11-14-ISF:16). SUBJECTS AND METHODS: Two hundred and fifty-seven children (mean age = 11.5 years, SD = 0.8, range = 9.8-13.5 years) completed the CPQ11-14-ISF:16 in conjunction with a clinical examination. In addition to malocclusions and orthodontic treatment need (based on the Index of Orthodontic Treatment Need-Dental Health Component), possible confounders (caries, enamel defects, dental trauma, headache and socio-economic markers) were recorded. Children also rated their own dental fear on the Children's Fear Survey Schedule-Dental Sub-scale (CFSS-DS). RESULTS: The mean total CPQ11-14-ISF:16 score was 9.31. The logistic regression analyses revealed an impact of orthodontic treatment need on OHRQoL (CPQ), but no clear association between higher severity and higher impact on OHRQoL was seen. Dental fear and headache appeared to discriminate for poorer OHRQoL. No impact from caries, enamel defects, dental trauma, or socio-economic markers was revealed. CONCLUSIONS: This cohort of children reported good self-perceived OHRQoL. Effects on OHRQoL from malocclusions or orthodontic treatment need were limited and inconsistent. Dental fear and headache were found to be more distinct impact factors on OHRQoL than were malocclusions or orthodontic treatment need.

Prevalence and aetiology of Molar-Incisor Hypomineralisation among children aged 8-10 years in Tirana, Albania.

AIM: Molar incisor hypomineralisation (MIH) describes the clinical appearance of enamel hypomineralisation of systemic origin affecting one or more permanent first molars (PFMs) that are frequently associated with affected incisors. The aim of this study was to investigate the prevalence and aetiology of MIH in children living in Tirana, Albania. DESIGN: The study was conducted at the Department of Paediatric and Preventive Dentistry, Faculty of Dental Medicine, and Tirana Dental Public Health Service. A total of 1,575 school children aged 8-10 years were examined by 7 calibrated examiners (dentists) (kappa: 0.86). The Weerheijm criteria were used for the diagnosis of demarcated opacities, post-eruption breakdown, atypical restorations, and extracted PFMs due to MIH. RESULTS: Prevalence of MIH was found to be 14% (n=227). In the 227 children with MIH, tooth 36 was the most affected PFM, and tooth 46 the least affected. Tooth 21 was the most affected incisor and tooth 32 the least affected incisor by MIH. MIH(+) children had significanly more childhood diseases in the first 3 years of life (p=0.006). Among the children who used antibiotics, MIH(+) cases were 1.41 (1.06-1.87) times higher than in children who did not usedantibiotics, MIH(-) cases. CONCLUSION: MIH was found to be common among 8-10 year-old Tirana children.

Prevalence of Enamel Markings on Third Molars.

The purpose of this study was to measure the prevalence of enamel markings in routinely extracted third molars. One hundred donated third molars were examined. All had some marking(s). Caries was almost universal; white snowcapping of cusps and ridges was extremely common; pit and valley defects were very common; spots and bands were very common, most were white; horizontal grooves were common; linear enamel hypoplasia, considered to be a true developmental defect, was rare.

Morphological analyses and a novel de novo DLX3 mutation associated with tricho-dento-osseous syndrome in a Chinese family.

Tricho-dento-osseous (TDO) syndrome, an autosomal-dominant disorder, affects the morphological appearance of the tooth enamel, hair, and bone. Previous studies have confirmed that mutations in the DLX3 gene are responsible for TDO. In this study, we describe a Chinese patient with the typical traits of TDO - kinky hair, enamel hypoplasia, skull and jaw bones thickening, and sclerosis. Unfortunately, as a result of excessive attrition, we were unable to assess taurodontism. Examination of the tooth ground section showed a thin layer of enamel with no rods on the patient's tooth and abnormalities in Tomes' granular layer and the dentinal tubules. Scanning electron microscopy and energy-dispersive X-ray spectroscopy of the tooth enamel showed significant differences between the patient and the control individuals. A hair sample from the patient observed under a laser-scanning microscope showed longitudinal grooves in the hair shaft. Dual-energy X-ray absorptiometry measurement showed that the bone mineral density values of the patient's bones was much higher than normal. Finally, genetic analysis revealed a novel de novo missense mutation c.533A>G (p.Q178R) in the conserved homeodomain of the DLX3 gene. This DLX3 mutation is the sixth causative mutation for TDO to be identified so far.

Non-invasive in vivo visualization of enamel defects by reflectance confocal microscopy (RCM).

The enamel defects (EDs) may present with a variety of clinical manifestations with increasing severity from the sole appearance of pale discoloration to remarkable structural alterations. EDs are responsible for higher caries receptivity. In vivo reflectance confocal microscopy (RCM) allows to image in vivo at microscopic resolution of the dental surface, thus avoiding the tooth extraction and the sample preparation because of its ability to optically scan living tissues along their depth. Aim of this study is the in vivo assessment at microscopic resolution of dental surfaces affected by EDs without resorting to invasive methods such as teeth extractions, to define histological findings occurring in chromatic and/or structural EDs. For the purpose, 15 children, referring at the Dental Clinic of the Second University of Naples, affected by several degrees of EDs, were enrolled and underwent in vivo RCM imaging to microscopically define the ED confocal features using a commercially available hand-held reflectance confocal microscope with neither injuries nor discomfort. Totally, 29 teeth were imaged. Results demonstrated images good in quality and the capability to detect EDs such as unevenness, grooves, and lack of mineralization according to their clinical degree of disarray. The present in vivo microscopic study on EDs allowed to highlight structural changes in dental enamel at microscopic resolution in real-time and in a non-invasive way, with no need for extraction or processing the samples. Further experiments could define the responsiveness to remineralizing procedures as therapeutic treatments.

How do children view other children who have visible enamel defects?

BACKGROUND: Facial and dental appearance influences how individuals are perceived by others. AIM: This study aimed to determine whether young people make judgements about other young people with visible enamel opacities. DESIGN: Focus group findings were used to develop a social attribute questionnaire to capture young people's dental appearance-related judgements. 547 pupils (aged 11-15 years), from two different schools, participated in the study. Half the participants were given full-face photographs of a boy and girl without an enamel defect, and the other half were given the same two photographs with the subjects' incisors digitally modified to show enamel opacities. Participants completed the attribute questionnaire to rate the photographic subjects according to six positive and five negative descriptors using a four-point Likert scale. The total attribute score (TAS) could range from 11 (most negative) to 44 (most positive). RESULTS: TAS was significantly lower for photographic subjects with enamel defects compared to the same subject with normal enamel appearance (P < 0.001, one sample t-test). Gender had a significant impact on TAS, with boys making more negative judgements than girls. Age and socio-economic status did not have an effect. CONCLUSION: Young people may make negative psychosocial judgements on the basis of enamel appearance.

Developmental Enamel Defects of the Permanent First Molars and Incisors and Their Association with Dental Caries in the Region of Wielkopolska, Western Poland.

PURPOSE: To assess the prevalence of developmental defects of the enamel (DDE) in permanent first molars and incisors and their association with dental caries in two age groups of children living in Wielkopolska, Poland. MATERIALS AND METHODS: The sample consisted of 225 children ages 6-8 years and 245 children ages 12-14 years (mean age ± SD = 9.9 ± 2.6). Dental defects were described using the modified DDE index. Caries experience was recorded using the DMFT index (number of decayed, missing and filled teeth) for all permanent teeth and for first permanent molars and incisors (DMFT-IM). RESULTS: Overall, 25.7% of the subjects had at least one permanent first molar or incisor affected by DDE. Diffuse opacity was the most common type of DDE, while hypoplasia was the least prevalent. The mean number of teeth with caries (DT) and the mean number of molars and incisors with caries (DT-IM) were higher in subjects with enamel hypoplasia and/or demarcated opacity than in subjects without DDE or with diffuse opacities (p < 0.05). Caries prevalence was higher in children with hypoplasia and/or demarcated opacity than in subjects without DDE. The differences were statistically significant only for the younger group (p < 0.05). CONCLUSION: The overall tooth prevalence of DDE in molars and incisors is comparable to that observed in low-fluoride communities. However, a preponderance of diffuse defects suggests the need for further investigation into the aetiology of DDE among Polish children. The results confirm that demarcated opacities and hypoplasia should be considered important caries risk factors.