Sandra Beatriz Chaves Tarquinio

Effects of Morphogen and Scaffold Porogen on the Differentiation of Dental Pulp Stem Cells

INTRODUCTION Dental pulp tissue engineering is an emerging field that can potentially have a major impact on oral health. However, the source of morphogens required for stem cell differentiation into odontoblasts and the scaffold characteristics that are more conducive to odontoblastic differentiation are still unclear. This study investigated the effect of dentin and scaffold porogen on the differentiation of human dental pulp stem cells (DPSCs) into odontoblasts. METHODS Poly-L-lactic acid (PLLA) scaffolds were prepared in pulp chambers of extracted human third molars using salt crystals or gelatin spheres as porogen. DPSCs seeded in tooth slice/scaffolds or control scaffolds (without tooth slice) were either cultured in vitro or implanted subcutaneously in immunodefficient mice. RESULTS DPSCs seeded in tooth slice/scaffolds but not in control scaffolds expressed putative odontoblastic markers (DMP-1, DSPP, and MEPE) in vitro and in vivo. DPSCs seeded in tooth/slice scaffolds presented lower proliferation rates than in control scaffolds between 7 and 21 days (p < 0.05). DPSCs seeded in tooth slice/scaffolds and transplanted into mice generated a tissue with morphological characteristics similar to those of human dental pulps. Scaffolds generated with gelatin or salt porogen resulted in similar DPSC proliferation. The porogen type had a relatively modest impact on the expression of the markers of odontoblastic differentiation. CONCLUSIONS Collectively, this work shows that dentin-related morphogens are important for the differentiation of DPSC into odontoblasts and for the engineering of dental pulp-like tissues and suggest that environmental cues influence DPSC behavior and differentiation potential.

A survey of oral and maxillofacial biopsies in children: a single-center retrospective study of 20 years in Pelotas-Brazil

Despite the large number of published cases about oral and maxillofacial pediatric lesions, the literature is scarce on epidemiological studies regarding the prevalence of these entities. This study retrieved oral and maxillofacial pediatric lesions from the Center of Diagnosis of Oral Diseases (CDDB) at the Dental School of the Federal University of Pelotas (UFPEL), comprising a 20-year period (1983-2002). From the total of 9,465 biopsies received in this period, 625 (6.6%) were from children aged 0 to 14 years. Regardless of the histopathological diagnosis, patient data referring to lesion location, sex and age were collected. Diagnoses were grouped in 13 categories. As much as 89% of the cases occurred in patients aged 7 to 14 years (53% in females and 47% in males). Mucocele (17.2%) was the most common type of lesion, followed by dentigerous cyst (8.6%). In the category of odontogenic tumors, odontoma was the most frequent lesion (64.2%). Malignant lesions were observed in a small section of the sample (1.2%). Generally, the results of the present study are in line with those reported in the literature concerning the most prevalent lesions in the pediatric population. Most lesions were benign, and malignant lesions were diagnosed in a very small part of the sample.

Tumor angiogenesis and lymphangiogenesis: Tumor/endothelial crosstalk and cellular/microenvironmental signaling mechanisms

Tumor angiogenesis and lymphangiogenesis are key features of tumor progression and metastasis. The role of tumor cells-derived factors in the promotion of associated angiogenesis and lymphangiogenesis is much studied and, no doubt, very important for the understanding of cancer progression. This review aims to present and discuss the work done on the pro-angiogenic and lymphangiogenic cellular interactions within the tumor microenvironment and the signaling pathways that regulate this crosstalk. Such multifactor studies are critical for the development of future therapeutic approaches for cancer because they take into account the complexities of cellular interactions within the tumor microenvironment.

Reattachment using a fragment from an extracted tooth to treat complicated coronal fracture

Reattachment of fragment is the preferred alternative to restore the fractured teeth, offering several advantages. Partial pulpotomy has demonstrated satisfactory results as a conservative treatment for pulp exposures because of trauma. This study reports a case in which the treatment of a complicated coronal fracture was accomplished by partial pulpotomy and reattachment of a dental fragment obtained from an extracted tooth using composite resin. The results show the feasibility of the conservative pulp therapy and the restorative approach.

Etiologic factors associated with oral squamous cell carcinoma in non-smokers and non-alcoholic drinkers: a brief approach

Oral squamous cell carcinoma (OSCC) is the fifth most common type of cancer in the world. The effect of some etiological factors is well established in the literature, such as consumption of tobacco and alcohol. However, approximately 15 to 20% of all oral cancer cases occur in patients without the traditional risk factors, reflecting in numerous cases of OSCC in non-smokers and non-alcoholic drinkers. Also, several studies have suggested a possible association between human papillomavirus and OSCC. Under these aspects, the purpose of this study is to address cases of oral cancer in non-smokers and non-drinkers focusing on the role of HPV, thus contributing to improve the diagnosis and monitoring of OSCC. A computer database search was performed using the Pubmed database. The search key words were: epidemiology, oral squamous cell carcinoma, risk factors and human papillomavirus. It is important to assess patients without the potential risk factors, since this knowledge may help identifying other features associated with the occurrence of oral cancer, enabling an appropriate clinical management and monitoring.

Oral health studies in the 1982 Pelotas (Brazil) birth cohort: methodology and principal results at 15 and 24 years of age

The aim of this study was to describe the methodology and results of oral health studies nested in a birth cohort in Pelotas, Southern Brazil. For the oral health studies a sub-sample (n = 900) was selected from the cohort and dental examinations and interviews were performed at ages 15 (n = 888) and 24 years (n = 720; 81.1%). Data collection included dental outcomes, dental care, oral health behaviors, and use of dental services. Mean DMF-T varied from 5.1 (SD = 3.8) to 5.6 (SD = 4.1) in the study period. The proportion of individuals with at least one filled tooth increased from 51.9% to more than 70%. Individuals who had always been poor used dental services less and had fewer healthy teeth on average than those who had never been poor. Individuals with decreasing or increasing family income trajectories showed intermediate values. An increase was seen in the number of healthy teeth from age 15 to 24 only among those who had never been poor. A history of at least one experience with poverty had a negative impact on oral health in adulthood.

Histologic response and tenascin and fibronectin expression after pulp capping in pig primary teeth with mineral trioxide aggregate or calcium hydroxide.

This study evaluated the histological response and the expression of tenascin (TN) and fibronectin (FN) after pulp capping with mineral trioxide aggregate (MTA) or calcium hydroxide (CH). Class V cavities and pulp exposure were performed in 40 primary pig teeth. The pulps were capped with either MTA or CH, and the cavities were sealed with resin-modified glass ionomer cement. CH was used as a control. Seven and 70 days posttreatment, the animals were sacrificed and teeth were prepared for histological evaluation. TN and FN were detected by immunostaining. A severe inflammatory response was observed after 7 days in the CH group (p<0.043), while in the MTA group, a mild response was observed. Similar reparative dentin deposition was observed after 70 days for both groups (p<0.005). The expression of FN and TN was similar for both groups in the two periods evaluated. TN and FN were expressed during pulp reparative events, independently of the capping material.

Influence of the restoration quality on the success of pulpotomy treatment: a preliminary retrospective study.

The aim of this study was to evaluate the clinical status of pulpotomy treatment with calcium hydroxide and to correlate it with the quality of restoration of the treated teeth. Patients were retrieved from the files of the Operative Dentistry clinics (FOUFPel) between 1996 and 2000. Twenty-two patients were recalled, which had 23 teeth treated with pulpotomy due to exposure by caries. Seven anterior and 16 posterior teeth composed the evaluated group, being all restored with composite resin. The age varied from 15-50 years (mean 23.9) and the follow-up mean was 34.52 months. Clinical and radiographic examinations were performed to evaluate the clinical status of treatment. The criteria used, clinically favorable and failure, were based on the following clinical exams: pulp vitality; sensitivity; and periapical alterations. The quality of the restorations was based on the USPHS criteria. Pulpotomy treatment was ranked as clinically favorable in 10 teeth (43.5%), 4 in anterior and 6 in posterior teeth. Failure was verified in 13 teeth (56.5%), 4 anterior and 9 posterior. From the group clinically favorable, 90% of the restorations were ranked as clinically satisfactory, while only 10% were unsatisfactory. In the failure group, 77.8% of the restorations were classified was unsatisfactory and 22.2% were ranked as satisfactory. The statistical analysis (Fisher´s exact test) demonstrated that there is a statistically significant association between the clinical status of pulpotomy and restoration quality (p<0.05). Within the limitation of the study, it was verified that the quality of restoration could influence the favorable clinical status of pulpotomized teeth. Randomized clinical trials are required to confirm these preliminary data.

Telomeres and Tissue Engineering: The Potential Roles of TERT in VEGF-mediated Angiogenesis

Telomeres are protective structures located at the end of eukaryotic chromosomes which are shortened after each cell division, leading to senescence. Telomerase activity prevents telomere shortening by reverse transcription catalyzed by the subunit called TERT (telomerase reverse transcriptase). TERT expression has shown interesting cellular properties, which may be appealing for tissue engineering, such as the enhancement of cell proliferation and differentiation abilities in vitro. Despite some evidence for playing these roles in VEGF (vascular endothelial growth factor)-mediated angiogenesis, it is still unclear whether TERT can contribute to this essential event to generate functional organs. This review suggests a hypothesis that TERT and VEGF potentially regulates the transcriptional expression of each other, which would give new perspectives in the roles of telomerase in regulating several cellular processes, and also contributing for a better comprehension of the molecular mechanisms underlying VEGF signaling (both paracrine and autocrine). In general, based on the literature revised, it is possible to conclude that TERT is a potential VEGF enhancer; however, it is necessary to elaborate methodological approaches to explore this potential and to assess the potential benefits on tissue engineering approaches.Telomeres are protective structures located at the end of eukaryotic chromosomes which are shortened after each cell division, leading to senescence. Telomerase activity prevents telomere shortening by reverse transcription catalyzed by the subunit called TERT (telomerase reverse transcriptase). TERT expression has shown interesting cellular properties, which may be appealing for tissue engineering, such as the enhancement of cell proliferation and differentiation abilities in vitro. Despite some evidence for playing these roles in VEGF (vascular endothelial growth factor)-mediated angiogenesis, it is still unclear whether TERT can contribute to this essential event to generate functional organs. This review suggests a hypothesis that TERT and VEGF potentially regulates the transcriptional expression of each other, which would give new perspectives in the roles of telomerase in regulating several cellular processes, and also contributing for a better comprehension of the molecular mechanisms underlying VEGF signaling (both paracrine and autocrine). In general, based on the literature revised, it is possible to conclude that TERT is a potential VEGF enhancer; however, it is necessary to elaborate methodological approaches to explore this potential and to assess the potential benefits on tissue engineering approaches.

Buccal cells submitted to three different storage conditions before DNA extraction

This study evaluated quantitatively and qualitatively the effect of the storage time of samples before the application of the cell lysis solution (CLS) for extracting DNA from buccal cells (BC). BC from the upper and lower gutter region were collected from 5 volunteers using special cytobrushes (Gentra), totaling 3 collections for each individual. In the control group (n=10), CLS was applied soon after BC collection. In the other two groups, samples were stored at room temperature (n=10) or at 4°C (n=10). After CLS application, DNA was extracted according to the manufacturer s instructions (Puregene DNA Buccal Cell Kit; Gentra Systems, Inc.). The DNA obtained was evaluated by two calibrated blind examiners using spectrophotometry and analysis of DNA bands (0.8% agarose gel electrophoresis). The obtained data were submitted to one-way ANOVA. The means and standard deviations for DNA extracted under immediate, room temperature and cooling temperature conditions were 3.5 ± 0.7, 3.0 ± 0.6 and 4.1 ± 1.8 μg, respectively (p=0.385). No significant differences were found in relation to the amount of DNA for the different storage conditions. However, in the visual analysis of the DNA bands, no trace of DNA degradation was detected when CSL was applied soon after DNA collection, while DNA bands with degradation could be observed in the other groups. Within the limitations of the study, it may be concluded that CLS should be applied soon after DNA collection in order to obtain high-quality DNA from BC.