Objective. To determine the prevalence of demarcated opacities in permanent 1st molars and incisors in 7 to 13-year-old Brazilian children. Material and methods. The study population comprised 292 children from a middle social class public school in Rio de Janeiro, Brazil. Children with all 1st permanent molars erupted were eligible for participation. Clinical examination was performed by two calibrated examiners who recorded demarcated opacities, post-eruptive breakdown, atypical restorations, and extractions due to demarcated opacities. Forty-three children had at least one molar that could not be examined, which left 249 children for the data analysis. Results. One hundred children (40.2%) had one or more 1st molars with demarcated opacities with a mean number of 1.98 (SD 1.09) affected molars. The number of affected incisors increased with increasing number of affected molars. Twenty-two (18.6%) of 118 children with unaffected 1st molars had affected incisors. Demarcated opacities were the most frequent defect, and 1st molars and upper central incisors were the most frequently affected teeth. Among children with demarcated opacities in 1st molars, 20 (20%) had post-eruptive breakdown. Conclusions. A high prevalence of demarcated opacities, possibly resulting in disintegration of the tooth crown, has been found in Brazilian children.

In recent years, Molar Incisor Hypomineralization (MIH) has become a subject that concerns the Paediatric Dentistry Community. The aim of the present umbrella review was to analyse previously publi...

A particular clone (JP2) of Actinobacillus actinomycetemcomitans with increased leukotoxin production has been isolated from individuals with early-onset periodontitis (EOP). The aim of this study was to determine the frequency of carriers of this clone and its association with EOP in Moroccan schoolchildren. Of 217 plaque samples, 131 (60.4%) were culture-positive for A. actinomycetemcomitans. A total of 19 of these isolates had a 530-bp deletion in the leukotoxin promoter region characteristic of the JP2 clone. A strong association between the presence of A. actinomycetemcomitans with the 530-bp deletion and EOP was found (adjusted OR = 29.4; 95% CI = 8.3 - 104.4; p < 0.0005), while no association could be demonstrated between the presence of A. actinomycetemcomitans without the deletion and EOP (adjusted OR = 1.3; 95% CI = 0.5 - 2.9; p = 0.750). The study demonstrates that the endemic presence, in a human population, of the highly leukotoxic JP2 clone may result in an unusually high prevalence of EOP.

Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium that is part of the oral microbiota. The aggregative nature of this pathogen or pathobiont is crucial to its involvement in human disease. It has been cultured from non-oral infections for more than a century, while its portrayal as an aetiological agent in periodontitis has emerged more recently. A. actinomycetemcomitans is one species among a plethora of microorganisms that constitute the oral microbiota. Although A. actinomycetemcomitans encodes several putative toxins, the complex interplay with other partners of the oral microbiota and the suppression of host response may be central for inflammation and infection in the oral cavity. The aim of this review is to provide a comprehensive update on the clinical significance, classification, and characterisation of A. actinomycetemcomitans, which has exclusive or predominant host specificity for humans.