Prevalence and Periodontal Conditions of Developmental Grooves in an Italian School of Dentistry and Dental Hygiene: A Cross-Sectional Study.

Background: The aim of this cross-sectional study was to (i) determine the prevalence and distribution of developmental grooves in a young population and (ii) to evaluate the local periodontal conditions. Methods: Two hundred and fifty-one students with a mean age of 22.9 ± 4.7, attending the School of Dentistry and Dental Hygiene of Vita-Salute San Raffaele University (Milan, Italy) were included. The subjects underwent a clinical evaluation by two calibrated examiners. The following clinical parameters were recorded for each site presenting a radicular groove and for each corresponding site on an adjacent tooth used as control: probing pocket depth, plaque index, bleeding on probing, recession depth. Results: The prevalence of radicular grooves at patient and tooth level was 15.9% and 5%, respectively. When compared to control sites, the number of teeth with a radicular groove that presented plaque and bleeding on probing was higher. The logistic regression analysis showed that the presence of radicular grooves was significantly associated with the presence of plaque (OR, 6.14, p < 0.001) and of bleeding on probing (OR, 2.91, p = 0.01). Conclusions: The presence of radicular grooves increases the possibility of developing gingival inflammation by acting as a plaque retentive factor.

The Emerging Role of Stem Cells in Regenerative Dentistry.

Progress of modern dentistry is accelerating at a spectacular speed in the scientific, technological and clinical areas. Practical examples are the advancement in the digital field, which has guaranteed an average level of prosthetic practices for all patients, as well as other scientific developments, including research on stem cell biology. Given their plasticity, defined as the ability to differentiate into specific cell lineages with a capacity of almost unlimited self-renewal and release of trophic/immunomodulatory factors, stem cells have gained significant scientific and commercial interest in the last 15 years. Stem cells that can be isolated from various tissues of the oral cavity have emerged as attractive sources for bone and dental regeneration, mainly due to their ease of accessibility. This review will present the current understanding of emerging conceptual and technological issues of the use of stem cells to treat bone and dental loss defects. In particular, we will focus on the clinical application of stem cells, either directly isolated from oral sources or in vitro reprogrammed from somatic cells (induced pluripotent stem cells). Research aimed at further unraveling stem cell plasticity will allow to identify optimal stem cell sources and characteristics, to develop novel regenerative tools in dentistry.

Microarray evaluation of age-related changes in human dental pulp.

INTRODUCTION: The dental pulp undergoes age-related changes that could be ascribed to physiological, defensive, or pathological irritant-induced changes. These changes are regulated by pulp cell activity and by a variety of extracellular matrix (ECM) macromolecules, playing important roles in growth regulation, tissue differentiation and organization, formation of calcified tissue, and defense mechanisms and reactions to inflammatory stimuli. The aim of this research was to better understand the genetic changes that underlie the histological modification of the dental pulp in aging. METHODS: The gene expression profile of the human dental pulp in young and older subjects was compared by RNA microarray analysis that allowed to simultaneously analyze the expression levels of thousands of genes. Data were statistically analyzed by Significance Analysis of Microarrays (SAM) Ingenuity Pathway Analysis (IPA) software. Semiquantitative and real-time reverse-transcriptase polymerase chain reaction analyses were performed to confirm the results. RESULTS: Microarray analysis revealed several differentially expressed genes that were categorized in growth factors, transcription regulators, apoptosis regulators, and genes of the ECM. The comparison analysis showed a high expression level of the biological functions of cell and tissue differentiation, development, and proliferation and of the immune, lymphatic, and hematologic system in young dental pulp, whereas the pathway of apoptosis was highly expressed in older dental pulp. CONCLUSIONS: Expression profile analyses of human dental pulp represent a sensible and useful tool for the study of mechanisms involved in differentiation, growth and aging of human dental pulp in physiological and pathological conditions.

Microarray expression profiling of human dental pulp from single subject.

INTRODUCTION: Microarray is a recently developed simultaneous analysis of expression patterns of thousand of genes. The aim of this research was to evaluate the expression profile of human healthy dental pulp in order to find the presence of genes activated and encoding for proteins involved in the physiological process of human dental pulp. We report data obtained by analyzing expression profiles of human tooth pulp from single subjects, using an approach based on the amplification of the total RNA. METHODS: Experiments were performed on a high-density array able to analyse about 21,000 oligonucleotide sequences of about 70 bases in duplicate, using an approach based on the amplification of the total RNA from the pulp of a single tooth. Obtained data were analyzed using the S.A.M. system (Significance Analysis of Microarray) and genes were merged according to their molecular functions and biological process by the Onto-Express software. RESULTS: The microarray analysis revealed 362 genes with specific pulp expression. Genes showing significant high expression were classified in genes involved in tooth development, protoncogenes, genes of collagen, DNAse, Metallopeptidases and Growth factors. CONCLUSION: We report a microarray analysis, carried out by extraction of total RNA from specimens of healthy human dental pulp tissue. This approach represents a powerful tool in the study of human normal and pathological pulp, allowing minimization of the genetic variability due to the pooling of samples from different individuals.