IgG4-positive plasma cells are more often detected in chronic periapical lesions arising from permanent rather than primary teeth.

AIM: To characterize plasma cell subsets in chronic periapical lesions affecting permanent and primary teeth. METHODOLOGY: Only chronic periapical lesions without root canal treatment were selected. Twenty-one radicular cysts and 7 periapical granulomas affecting permanent teeth and 19 radicular cysts and 4 periapical granulomas affecting primary teeth were assessed for immunoglobulin (Ig) light chain (kappa and lambda), Ig heavy chain (IgG, IgG4, IgA, IgM and IgD) and plasma cell immunohistochemical markers (MUM1/IRF4, EMA and CD138). The data acquired were analysed by Student's t test, Mann-Whitney U, Friedman test followed by Dunn's multiple comparison test and Spearman's rank correlation. RESULTS: All cases were polyclonal (having similar kappa/lambda light chain ratios). IgG was most abundant compared to other Ig heavy chains (all, P < 0.001); like Ig light chains, but unlike IgA, there was greater expression of IgG in the primary compared to the permanent dentition, for both radicular cysts (P < 0.001) and periapical granulomas (P = 0.53). Notably, IgG4 expression was greater in the permanent than the primary dentition, for both radicular cyst (P < 0.05) and periapical granuloma (P = 0.65). IgM and IgD expression was scarce and variable, whereas plasma cell populations were detected efficiently through EMA, CD138 and MUM1/IRF4 markers, the latter being more sensitive in both dentitions. CONCLUSIONS: There were slight variations in the Ig light and heavy chain profiles in chronic periapical lesions when comparing the permanent and primary dentitions. The ability of IgG4+ plasma cell infiltration to modulate inflammatory responses in chronic periapical lesions arising from permanent as opposed to primary teeth should be considered in future studies.

Congenital and acquired defects in enamel of primary teeth: prevalence, severity and risk factors in Brazilian children.

OBJECTIVE: This cross-sectional study evaluated the prevalence of tooth enamel defects and risk factors associated in primary dentition. METHODS: A sample of 656 schoolchildren (population based), aged 4 years old, from Araraquara-SP (Brazil) was evaluated by two trained examiners according to the following indexes: Dental fluorosis (DF), deciduous molar hypomineralization (DMH), non-fluoride related developmental defects of enamel (DDE), tooth erosion and tooth attrition. Structured questionnaires identified socioeconomic condition, medical/dental history, behavior and dietary habits. Data were analyzed using Chi-square tests (p < 0.05). RESULTS: Of the enamel congenital defects, DF was the most prevalent (6.1%, n = 40), followed by DMH (5.6%, n = 37). Of the acquired defects, attrition was the most prevalent (36.9%, n = 242), followed by erosion (2.4%, n = 16). The caries experience was similar between the affected children (29,5%; n = 94) and total sample (30.6%; n = 201). The etiological factors related to congenital defects were: not exclusively fed breast milk (p = 0.003) and jaundice at birth (p < 0.001); the association with acquired defects was found with vomiting frequent episodes (p = 0.037). CONCLUSION: The general prevalence of enamel defects in primary dentition in Araraquara was 48.6%. Enamel defects may be associated with health-related factors and current lifestyle.