Carel Brigi

Bio: Carel Brigi is an academic researcher from Ajman University of Science and Technology. The author has contributed to research in topics: Tap water & Red complex. The author has an hindex of 2, co-authored 5 publications receiving 10 citations.

The prevalence of novel periodontal pathogens and bacterial complexes in Stage II generalized periodontitis based on 16S rRNA next generation sequencing.

Abstract: Objective: To define the subgingival microbial profile associated with Stage II generalized periodontitis using next-generation sequencing and to determine the relative abundance of novel periodontal pathogens and bacterial complexes. Methodology: Subgingival biofilm samples were collected from 80 subjects diagnosed with Stage II generalized periodontitis. Bacterial DNA was extracted, and 16S rRNA-based bacterial profiling via next-generation sequencing was carried out. The bacterial composition and diversity of microbial communities based on the age and sex of the patients were analyzed. The bacterial species were organized into groups: bacterial complexes (red, orange, purple, yellow, and green), novel periodontal pathogens, periodontal health-related species, and unclassified periodontal species. The results were analyzed and statistically evaluated. Results: The highest number of bacteria belonged to the phylum Bacteroidetes and Firmicutes. In terms of relative abundance, the orange complex represented 18.99%, novel bacterial species (Fretibacterium spp. and Saccharibacteria spp.) comprised 17.34%, periodontal health-related species accounted for 16.75% and unclassified periodontal species represented (Leptotrichia spp. and Selenomonas spp.) 15.61%. Novel periodontal pathogens had outweighed the periodontal disease-related red complex (5.3%). The one-sample z-test performed was statistically significant at p<0.05. The Beta diversity based on the unweighted UniFrac distance at the species level demonstrated a total variance of 15.77% based on age and 39.19% on sex, which was not statistically significant. Conclusion: The bacterial species corresponding to the disease-related orange complex and novel periodontal pathogens are predominant in Stage II generalized periodontitis.

Comparative evaluation of surface roughness of posterior primary zirconia crowns.

Abstract: To compare the surface roughness of four commercially available posterior zirconia crowns on the occlusal surface and occlusal edge (buccal cusps) of first and second primary molars crowns. Surface roughness of 40 posterior primary zirconia crowns was measured using a mechanical stylus profilometer. Ten mandibular right molar crowns, consisting of five first primary molar and five second primary molar crowns from four brands—Cheng, Sprig EZCrowns, NuSmile and Kinder Krowns were selected. Mean roughness, Ra and mean roughness depth, Rz was measured for all crowns on two selected surfaces, occlusal surface and buccal cusp tips. Data was evaluated by one way analysis of variance and Tukey’s honestly significant difference test at 0.05 level of significance. Statistically significant differences were observed in the mean Ra and Rz values at both selected surfaces among four prefabricated paedodontic zirconia crowns. Kinder Krowns had higher Ra and Rz values compared to Cheng, Sprig EZCrowns and NuSmile. Roughness profile of Kinder Krowns also showed higher vertical scale values co-relating with higher Ra and Rz scores, irrespective of the measurements taken on relatively flat surfaces (occlusal edge) or deeper surface (occlusal pits and fissures). Mechanically polished posterior primary zirconia crowns had a smoother surface profile than the combined polished-glazed primary zirconia crowns. Cheng Crowns had the lowest mean Ra and Rz values although not statistically significant from Sprig EZCrowns and Nu Smile. Kinder Krowns had the highest mean Ra and Rz scores than other crown groups.

Interproximal contact areas of primary molars based on OXIS classification - a two centre cross sectional study

Abstract: Background: Contact areas in primary teeth are known to be broader, flatter and situated farther gingivally than permanent teeth The purpose of this study was to assess the prevalence of OXIS contact areas between primary molars using die models of children from two different ethnic populations The research question of the present study is “What is the prevalence OXIS contact areas of primary molars in the populations studied?” Methods: A cross-sectional study was planned in a representative sample of 200 caries-free contact areas among children aged 3-6 years in two centers, Ajman and Puducherry Data collection was performed from sectional or full-arch die stone models The contacts were assessed according to OXIS classification by a single calibrated examiner at Center 2 Prevalence was expressed as numbers and percentages The Chi-square test was applied to determine the association of OXIS contacts across genders and arches Results: The prevalence of O, X, I, and S contacts were 19%, 225%, 53%, and 55% in Center 1 and 6%, 15%, 755%, and 17% in Center 2, respectively Significant results (p=0005) were obtained in Center 1 when inter-arch comparison was performed and between the centers with respect to type of contact No significant difference was obtained with respect to gender and OXIS contact areas Conclusions: The present study confirmed OXIS contacts in both the centers The ‘O’ and ‘X’ types of contacts were observed more in Center 1, whereas ‘I’ and ‘S’ contacts were observed more in Center 2

Parental perceptions and drinking water source among pediatric population in the United Arab Emirates

Abstract: Aims: The aim of the study is to determine the water source used for drinking and cooking purpose by the pediatric population in the United Arab Emirates (UAE). To ascertain the underlying factors influencing the parental choice for selecting tap water or bottled water. The study was also done to evaluate whether demographic factors have an influence on the parental choice of water consumption source.Materials and Methods: A total of 200 parents who had children aged between 3- and 15-year-old were chosen for this randomized cross-sectional study. The parents of the selected children were given a prewritten questionnaire consisting of 12 questions in four different languages. The questionnaires documented sociodemographic characteristics, water consumption practices, and the rationale for choosing bottled water and tap water. The responses were analyzed using descriptive statistics and a Chi-square test for a single proportion. Results: Majority of the parents in this study preferred bottled water to tap water for drinking and cooking purposes. About 84% of the parents opted bottled water for drinking and 57% selected bottled water for cooking at home. The consumption of tap water for drinking purpose from school and home was only 13% and 16%, respectively. Parental educational background and household income did not affect their selected source of water. A Chi-square test of independence conducted to investigate possible association between source of water and its purpose for drinking and cooking revealed that the source of water (tap/bottled water) was dependent on its purpose. Conclusion: A greater percentage of the UAE pediatric population utilized bottled water for drinking at school and home. The perceptions about the quality and safety of tap water had a great effect on the caregiver's choice on children's water consumption habits. The demographic factors such as socioeconomic status and parental education had no influence on the source of water used for drinking purpose.

OXIS contact areas of primary molars - a two center cross-sectional study.

Abstract: Background: Contact areas in primary teeth are known to be broader, flatter and situated farther gingivally than permanent teeth. The purpose of this study was to assess the prevalence of OXIS contact areas between primary molars using die models of children from two different ethnic populations. The research question of the present study is “What is the prevalence OXIS contact areas of primary molars in the populations studied?”. Methods: A cross-sectional study was planned in a representative sample of 200 caries-free contact areas among children aged 3-6 years in two centers, Ajman and Puducherry. Data collection was performed from sectional or full-arch die stone models. The contacts were assessed according to OXIS classification by a single calibrated examiner at Center 2. Prevalence was expressed as numbers and percentages. The Chi-square test was applied to determine the association of OXIS contacts across genders and arches. Results: The prevalence of O, X, I, and S contacts were 19%, 22.5%, 53%, and 5.5% in Center 1 and 6%, 1.5%, 75.5%, and 17% in Center 2, respectively. Significant results (p=0.005) were obtained in Center 1 when inter-arch comparison was performed and between the centers with respect to type of contact. No significant difference was obtained with respect to gender and OXIS contact areas. Conclusions: The present study confirmed OXIS contacts in both the centers. The ‘O’ and ‘X’ types of contacts were observed more in Center 1, whereas ‘I’ and ‘S’ contacts were observed more in Center 2.

Surface, Microstructural, and Mechanical Characterization of Prefabricated Pediatric Zirconia Crowns.

Abstract: The purpose of this study was to characterize the surface roughness, the microstructure, and mechanical properties of four prefabricated zirconia pediatric crowns. Ten prefabricated crowns from four different manufacturers (Cheng Crowns Zirconia), (EZCrowns), (NuSmile ZR), and (Zirconia Pediatric Crowns) were included in this study. The surface roughness parameters (Sa, Sq, Sz, Sc, and Sv) of all samples were studied by optical profilometry and then the microstructure was studied by Raman spectroscopy. Then, all samples were embedded in epoxy resin and after metallographic polishing, the Martens hardness (HM), indentation modulus (EIT), elastic index (ηIT), Vickers hardness (HV), and fracture toughness (KIC) were identified by the Instrumented Indentation Testing (IIT). All data were statistically analyzed by a one-way ANOVA and a Tukey multiple comparison test at α = 0.05. Only the tetragonal phase of zirconia for all materials tested was identified after Raman analysis. However, statistically significant differences were found among the surface roughness parameters, HV and KIC, while no differences were allocated for HΜ, EIT, and ηΙΤ. Although the materials tested shared a similar microstructure, significant differences in surface roughness parameters HV and KIC were identified and, thus, differences in their clinical performance were anticipated.

Tribological performance of the pair human teeth vs 3D printed zirconia: An in vitro chewing simulation study.

Abstract: This study aims to evaluate the tribological performance of the pair human teeth/robocasted zirconia, with a special focus on the enamel wear mechanisms. Zirconia pieces produced by robocasting (RC) and unidirectional compression (UC) were compared in terms of crystalline structure, density, porosity, hardness and toughness. Chewing simulation tests were performed against human dental cusps. The cusps wear was quantified and the wear mechanisms identified. Although most of the properties of UC and RC samples are similar, differences were observed for surface roughness and porosity. Although the samples did not suffer wear, the antagonist cusps worn in a similar way. In conclusion, robocasting seems a promising technique to produce customized zirconia dental pieces, namely in what concerns the overall tribological behaviour.

Use of Restorative Full Crowns Made with Zirconia in Children: A Systematic Review.

Abstract: Aim and objective The purpose of this systematic review is to analyze the suitability of the zirconia crowns for restoration of damaged primary teeth in children. Background This systematic review has been conducted in line with the preferred reporting items for systematic reviews (which is also called as PRISMA) guidelines. A search for the relevant articles of zirconia crowns in deciduous teeth has been made in electronic database of PubMed and a study design (meta-analysis), i.e., PICOS framework. The words used in the search are "zirconia crowns" and "primary molars," "zirconia crowns" and "primary incisors," "zirconia crowns" and "children," "zirconia crowns" and "primary teeth." Review results The database search showed 44 studies of which 20 articles were excluded as they were irrelevant, duplicates, and data were not available. In the present systematic review, the remaining 24 articles were included. Conclusion Zirconia crowns have been proved with better results than other crowns in terms of gingival and periodontal health, esthetics, and crown fractures. However, the quantity of tooth preparation and the wear of antagonist tooth are reported to be more in case of zirconia crowns. Future randomized control studies should be carried out in primary teeth due to less number of randomized studies on this topic. Clinical significance Zirconia crowns are now widely used in dentistry and there is an increase in the number of studies, so a systematic review evaluating and comparing results is warranted. How to cite this article Ajayakumar LP, Chowdhary N, Reddy VR, et al. Use of Restorative Full Crowns Made with Zirconia in Children: A Systematic Review. Int J Clin Pediatr Dent 2020;13(5):551-558.

Differences in the subgingival microbiome according to stage of periodontitis: A comparison of two geographic regions

Abstract: No microbiological criteria were included in the 2018 EFP-AAP classification of periodontal diseases that could be used to differentiate between stages and grades. Furthermore, differences in the subgingival microbiome depending on stage and grade have not been established. Sixty subgingival biofilm samples were collected in Spain (n = 30) and Colombia (n = 30) from three distinct patient categories: those with periodontal health/gingivitis (n = 20), those with stage I-II periodontitis (n = 20), and those with stage III-IV periodontitis (n = 20). Patients were evaluated by 16S rRNA gene amplification sequencing. Amplicon sequence variants were used to assign taxonomic categories compared to the Human Oral Microbiome Database (threshold ≥97% identity). Alpha diversity was established by Shannon and Simpson indices, and principal coordinate analysis, ANOSIM, and PERMANOVA of the UNIFRAC distances were performed using QIIME2. Although differences in the alpha diversity were observed between samples according to country, Filifactor alocis, Peptostreptococcaceae [XI][G-4] bacterium HMT 369, Fretibacterium fastidiosum, Lachnospiraceae [G-8] bacterium HMT 500, Peptostreptococcaceae [XI][G-5] [Eubacterium] saphenum, Peptostreptococcus stomatis, and Tannerella forsythia were associated with periodontitis sites in all stages. However, only F. alocis, Peptostreptococcaceae [XI][G-4] bacterium HMT 369, Peptostreptococcaceae [XI][G-9] [Eubacterium] brachy, Peptostreptococcaceae [XI][G-5] [Eubacterium] saphenum, and Desulfobulbus sp. HMT 041 were consistent in stage III-IV periodontitis in both countries. Porphyromonas gingivalis and Tannerella forsythia were differentially expressed in severe lesions in the countries studied. Although some non-cultivable microorganisms showed differential patterns between the different stages of periodontitis, they were not the same in the two countries evaluated. Further studies using larger samples with advanced next-generation techniques for high-throughput sequencing of phyla and non-cultivable bacteria within the subgingival microbiome could provide more insight into the differences between stages of periodontitis.

Complete Genomes of Clade G6 Saccharibacteria Suggest a Divergent Ecological Niche and Lifestyle.

Abstract: Saccharibacteria (formerly TM7) have reduced genomes and a small cell size and appear to have a parasitic lifestyle dependent on a bacterial host. Although there are at least 6 major clades of Saccharibacteria inhabiting the human oral cavity, complete genomes of oral Saccharibacteria were previously limited to the G1 clade. In this study, nanopore sequencing was used to obtain three complete genome sequences from clade G6. Phylogenetic analysis suggested the presence of at least 3 to 5 distinct species within G6, with two discrete taxa represented by the 3 complete genomes. G6 Saccharibacteria were highly divergent from the more-well-studied clade G1 and had the smallest genomes and lowest GC content of all Saccharibacteria. Pangenome analysis showed that although 97% of shared pan-Saccharibacteria core genes and 89% of G1-specific core genes had putative functions, only 50% of the 244 G6-specific core genes had putative functions, highlighting the novelty of this group. Compared to G1, G6 harbored divergent metabolic pathways. G6 genomes lacked an F1Fo ATPase, the pentose phosphate pathway, and several genes involved in nucleotide metabolism, which were all core genes for G1. G6 genomes were also unique compared to that of G1 in that they encoded d-lactate dehydrogenase, adenylate cyclase, limited glycerolipid metabolism, a homolog to a lipoarabinomannan biosynthesis enzyme, and the means to degrade starch. These differences at key metabolic steps suggest a distinct lifestyle and ecological niche for clade G6, possibly with alternative hosts and/or host dependencies, which would have significant ecological, evolutionary, and likely pathogenic implications. IMPORTANCESaccharibacteria are ultrasmall parasitic bacteria that are common members of the oral microbiota and have been increasingly linked to disease and inflammation. However, the lifestyle and impact on human health of Saccharibacteria remain poorly understood, especially for the clades with no complete genomes (G2 to G6) or cultured isolates (G2 and G4 to G6). Obtaining complete genomes is of particular importance for Saccharibacteria, because they lack many of the "essential" core genes used for determining draft genome completeness, and few references exist outside clade G1. In this study, complete genomes of 3 G6 strains, representing two candidate species, were obtained and analyzed. The G6 genomes were highly divergent from that of G1 and enigmatic, with 50% of the G6 core genes having no putative functions. The significant difference in encoded functional pathways is suggestive of a distinct lifestyle and ecological niche, probably with alternative hosts and/or host dependencies, which would have major implications in ecology, evolution, and pathogenesis.