Primary molar infraocclusion: frequency, magnitude, root resorption and premolar agenesis in a Spanish sample.

AIM: This study was conducted to determine frequency, distribution and magnitude of infraocclusion in primary mandibular molars; to evaluate root resorption, the frequency of premolars agenesis and the association between primary molar infraocclusion and premolar agenesis. MATERIALS AND METHODS: The sample consisted of 472 children who were subdivided in 3 age groups. The magnitude of infraocclusion was determined following the Bjerklin and Bennett method modified by the authors. Radicular resorption was determined using the rating scale proposed by Bjerklin and Bennett evaluating mesial and distal roots separately. The development degree of corresponding premolars was determined using the Demirjian method. RESULTS: One hundred and three (21.8%) children presented infraocclusion. The first primary molar presented infraocclusion in a significantly higher frequency. Considering the 3 scores of infraocclusion, 61.1% of the affected molars were classified as mild infraocclusion. No differences were found considering the root resorption pattern for primary molars, infraoccluded or not. Significant differences were found in the presence of agenesis in the group of infraoccluded molars. CONCLUSION: The present study identified a high percentage of infraocclusion, demonstrating that the type of molar is an influent variable, that the first primary molar is the most affected one, especially mandibular molars, and that the majority was mainly of a mild degree. There were no significant differences between the exfoliation of infraoccluded and non infraoccluded primary molars. However, radicular resorption of infraoccluded molars presented a clear delay or was totally absent in infraoccluded molars associated with premolar agenesis. Significant differences in the presence of agenesis beneath infraoccluded molars were observed.

Genetic variation in a wild population of the 'sleep' passion fruit (Passiflora setacea) based on molecular markers.

Little is known about the molecular genetic diversity of most Passiflora species. We used RAPD markers to evaluate the genetic diversity of 24 genotypes of the 'sleep' passion fruit (Passiflora setacea). Twelve primers generated 95 markers, 88% of which were polymorphic. The genetic distance estimated by the complement of the Dice index ranged from 0.29 (among accessions Ps-G1 and Ps-G13) to 0.69 (among accessions Ps-G21 and Ps-G23). Genotype grouping based on the UPGMA algorithm showed considerable variability among genotypes. We conclude that P. setacea has a broad genetic base that could be exploited in breeding programs.

Regional odontodysplasia. A literature review and three case reports.

AIM: The purpose of this article is to report some unusual characteristics related to gender, location and manifestations of severe Regional Odontodysplasia detected in three subjects. Regional Odontodysplasia is a rare disturbance of dental development whose aetiology is still unknown. Anomalies involve enamel, dentin, pulp and dental follicle causing atypical structure, colour, shape, size and eruptive disturbances of the affected teeth. Its early onset may lead to craniofacial development disturbances. CASES REPORTS: This article reports three cases with unusual characteristics observed in male children who were assisted by a paediatric dentist. Generally the disease affects one hemiarch and it is very rare that it crosses the midline as in one of the presented cases. Regional Odontodysplasia has been predominantly described in the maxilla and in women, however these three cases are in boys and two of them occured in the mandible. CONCLUSION: Regional Odontodysplasia is a rare disease, causing severe dental, growing and craniofacial development anomalies. Treatment needs to be personalised, aiming at preservation of the affected teeth taking into account their risk to develop severe infections. Parents should be made aware of the need for an extensive follow-up.

Microbiological analysis of gingivitis in pediatric patients under orthodontic treatment.

AIM: The aim of this study was to determine the relationship between gingival inflammation and changes in bacteria of the gingival sulcus in children in orthodontic treatment with brackets. STUDY DESIGN: this prospective study assessed gingival and plaque index of two groups: children with brackets (Group 1) and without brackets (Group 2). The sample was selected from patients treated at the Faculty of Dentistry, Complutense University of Madrid, Spain. Microbiological assessment was performed in every child and all data were statistically analysed. RESULTS: Group 1 showed significantly higher microbiological values and the difference was greater in lower teeth. Comparing the total plaque percentage, it was significantly higher in Group 1. STATISTICS: there was no significant correlation between gingival and plaque indexes in any group. No significant correlation was found between plaque index and bacteria. CONCLUSION: Children using brackets showed significantly higher gingival and plaque indices than children without brackets. No direct relationship was found between the increase in gingival and plaque indices and the presence and quantity of bacteria; therefore it was not possible to identify specific bacteria as responsible for the high gingival index in patients with brackets.

Genetic variability in wild genotypes of Passiflora cincinnata based on RAPD markers.

The genetic diversity and characteristics of commercial interest of Passiflora species make it useful to characterize wild germplasm, because of their potential use for fruit, ornamental and medicinal purposes. We evaluated genetic diversity, using RAPD markers, of 32 genotypes of Passiflora cincinnata collected from the wild in the region of Vitória da Conquista, Bahia, Brazil. Thirteen primers generated 95 polymorphic markers and only one monomorphic marker. The mean genetic distance between the genotypes estimated by the complement of the Dice index was 0.51 (ranging from 0.20-0.85), and genotype grouping based on the UPGMA algorithm showed wide variability among the genotypes. This type of information contributes to identification and conservation of the biodiversity of this species and for the identification of pairs of divergent individuals for maximum exploitation of existing variability.

Genetic diversity in wild species of passion fruit (Passiflora trintae) based on molecular markers.

In spite of the importance of and the considerable variability observed in Passiflora (Passifloraceae), little is known about the genetic diversity of most of the species of this genus. We evaluated the genetic diversity by RAPD markers in 18 genotypes of Passiflora trintae. The 15 primers generated 112 markers, 84% of which were polymorphic. The genetic distance estimated by the complement of the Dice index (average dissimilarity = 0.30) and genotype grouping based on the UPGMA algorithm showed low variability among genotypes. More attention should be given to the study and conservation of the biodiversity of this economically important genus.

Comparison of coefficients and distance measurements in passion fruit plants based on molecular markers and physicochemical descriptors.

We investigated seven distance measures and 14 similarity coefficients in a set of observations of variables of the 'yellow' passion fruit plant (Passiflora edulis Sims), submitted to multivariate analyses (distance, projection and grouping). Fourteen genotypes were characterized, based on DNA amplification with 16 random amplified polymorphic DNA primers and the assessment of nine fruit physical-chemical descriptors. The distance measurements and the similarity coefficients were compared by the Spearman correlation test, projection in two-dimensional space and grouping efficiency, using five grouping methods; the genotype ranking varied with the different techniques. Coler-Rodger distance measures, Euclidean distance square measures and Yule similarity coefficients proved to be inadequate for projection in two-dimensional space or for grouping matrices. Regardless of the origin of the distance matrix, the unweighted pair group method with arithmetic mean grouping method proved to be the most adequate. The various distance measurements, similarity coefficients and grouping methods gave different values of distortion, cophenetic correlation and stress; they influence the characterization of genetic variability and this should be taken into account for studies of yellow passion fruit plants.