Gerardo Moreu

In vitro and in vivo cytokeratin patterns of expression in bioengineered human periodontal mucosa.

BACKGROUND AND OBJECTIVE Development of human oral mucosa substitutes by tissue engineering may provide new therapeutic tools for the management of periodontal diseases. In this study we evaluated a fibrin-agarose human oral mucosa substitute both in vitro and in vivo. MATERIAL AND METHODS In vitro bioengineered oral mucosa substitutes were developed from irrelevant biopsy samples of human oral gingiva. In vivo evaluation of the constructed tissues was performed by implantation into athymic nude mice. The expression of several epithelial markers was assessed by microarray analysis and immunohistochemistry. RESULTS Bioengineered oral mucosa samples kept in vitro developed a multilayered epithelium that expressed several cytokeratins, including some markers of simple epithelia (cytokeratins 7, 8 and 18), along with markers of stratified epithelia (cytokeratins 5 and 13) and of cell proliferation (proliferating cell nuclear antigen). Bioengineered tissues grafted in vivo onto nude mice exhibited very good biointegration with the host, showing a cytokeratin expression pattern that was very similar to that of normal native oral mucosa controls. Histological analysis of the artificial tissues demonstrated that oral mucosa substitutes evaluated in vivo were structurally mature, showing some typical structures of human native oral mucosa such as rete ridges and chorial papillae, along with numerous blood vessels at the fibrin-agarose stromal substitute. These structures were absent in samples evaluated in vitro. CONCLUSION The results indicate that this model of human oral mucosa, constructed using fibrin-agarose scaffolds, shows similarities to native oral mucosa controls and imply that bioengineered oral mucosa substitutes could eventually be used clinically.

Dental extraction in patients receiving dual antiplatelet therapy.

Background Dual anti platelet therapy consists of administering antiplatelet (antiaggregant) drugs (clopidogrel and aspirin) to prevent thrombotic processes, as a preventative measure in patients with acute coronary disease, or in patients subjected to percutaneous coronary intervention. Objectives The purpose of this study was to evaluate the efficacy of a protocol for performing dental extraction in patients receiving dual anti platelet therapy. Material and Methods Thirty-two patients undergoing dental extractions were included in the study. The variables evaluated were: collagen-epinephrine fraction, collagen- adenosine diphosphate fraction, surgical surface, post-surgical measures, and adverse effects. Alveolar sutures and gauzes impregnated with an antifibrinolytic agent (tranexamic acid), which the patient pressed in place for 30 minutes, were applied to all patients as post-surgical measures. Descriptive statistics were calculated and analyzed with Student’s t-test to compare pairs of quantitative variables; simple regression analysis was performed using Pearson’s correlation coefficient. Statistical significance was set at p<0.05. Results Collagen/epinephrine fraction was 264.53±55.624 seconds with a range of 135 to 300 seconds, and collagen/ADP fraction was 119.41±44.216 seconds, both values being higher than normal. As a result of the post-surgical measures taken, no patients presented postoperative bleeding, hematoma or infection. Conclusions Dental extraction was safe for patients receiving dual anti-platelet therapy when using sutures and gauze impregnated with tranexamic acid, which the patient pressed in place for 30 minutes. Key words: Aspirin, clopidogrel, tranexamic acid, dental extraction, platelet function.

Periodontal status during pregnancy and postpartum

Objectives Different studies have documented an association between periodontal disease and low birth-weight delivery. Hence, knowledge of periodontal status during pregnancy and postpartum is important in order to reduce the risks of both diseases. This study aimed to analyze periodontal status at successive stages of pregnancy and 3–6 weeks postpartum in women with initial periodontal alterations. Materials and methods Ninety-six pregnant women were examined at 8–10 weeks (pregnancy diagnosis, baseline), 21–23 weeks and 34–36 weeks of gestation and at 40 days postpartum to record plaque scores, clinically assessed gingival inflammation and probing depth (mean depth and % sites with depth >3 mm). Bivariate and multivariate analyses were performed. Type 1 (α) error was established at 0.05 Results Plaque Index increased (p = 0.043) throughout pregnancy (baseline, 42%±0.18); 21–23 weeks, 42.6%±0.14; 34–36 weeks, 45.6%±0.13 and decreased postpartum (44.8%±0–13). Gingival Index increased (p<0.001) throughout pregnancy (baseline, 56.7%±0.20; 21–23 weeks, 66.36%±0.17; 34–36 weeks, 74.5%±0.18) and decreased postpartum (59.3%±0.21). Probing Depth increased (p<0.001) throughout pregnancy (baseline, 2.51±0.05; 21–23 weeks, 2.63±0.053; 34–36 weeks 2.81±0.055) and decreased postpartum (2.54±0.049). Percentage of sites with Probing Depth >3 mm increased (p<0.001) throughout pregnancy (baseline, 17.6%±0.16; 21–23 weeks, 23.9%±0.17; 34–36 weeks, 31.1%±0.17) and decreased postpartum (21.2%±0.17) but remained significantly (p<0.02) higher than at baseline. Conclusion Periodontal status deteriorates during gestation but improves postpartum.

Bisphosphonates, vitamin D, parathyroid hormone, and osteonecrosis of the jaw. Could there be a missing link?

It is estimated that over 190 million bisphosphonates have been prescribed worldwide. But this drug can produce adverse effects, of which osteonecrosis of the jaw and severe hypocalcemia are the most serious. It is evident that bisphosphonate administration affects multiple and diverse biochemical mediators related to bone metabolism. This review of literature investigates four basic parameters in patients treated with bisphosphonates - parathyroid hormone (PTH), bisphosphonates, vitamin D, calcium, and jaw osteonecrosis - which are fundamental for assessing bone metabolism and so the efficacy and correct use of the drug. The imbalances generated by vitamin D and calcium deficiencies, together with their multiple systemic repercussions, have been widely researched but the outcomes of these imbalances in relation to bisphosphonate administration are not well known, and some research has indicated that they may be associated with osteonecrosis of the jaw (ONJ). The present review set out to explain the functioning of bone metabolism, the importance of different chemical mediators, the imbalances produced by incorrect use of this drug, in order to forewarn against the possible relation of these parameters with ONJ, whose physiopathology remains unknown. Medical and dental clinics should keep detailed anamneses of the use of vitamin D and calcium supplements, as it is of vital importance to maintain their correct levels in blood, given that these are related to ONJ as well as other adverse effects; this procedure is also necessary in order to ensure the correct use of the drug. Key words:Bisphosphonate-related osteonecrosis of the jaw, vitamin D, parathyroid hor

Torsion ultrasonic sensor for tissue mechanical characterization

A sensor based on torsional waves is proposed, designed and validated to quantify elastic constants of soft tissue. The proposed transducer design is able to deploy a shear wave elastography technique that accurately quantifies the shear viscoelastic moduli of the tissue, which, as opposed to compression waves, are strongly dependent on the stroma architecture, thus serving as a new biomarker.

Periodontal and biochemical bone metabolism assessment on a chronic oral anticoagulation population treated with dicoumarins.

Background The aim is to evaluate periodontal alteration and biochemical markers associated with bone turnover in chronic oral with dicoumarins anticoagulant treatment patients. Material and Methods 80 patients treated with oral anticoagulants were divided into 2 cohort: Group A (n=36) 6 month to 1 year with anticoagulant treatment and Group B (n=44) > 2 years with anticoagulant treatment. Clinical evaluation included: Clinical attachment level (CAL), plaque index (PI) and gingival index (GI). Analytically biochemical parameters of bone remodeling (calcium and phosphorus), formation (total acid phosphatase, alkaline phosphatase and osteocalcin) and resorption (tartrate-resistant acid phosphatase and beta-crosslaps) were evaluated. Results High values of PI (67-100%) especially in men and in Group B were observed. Men with anticoagulation treatment length showed an increased GI (49.167 vs 78.083) while Group B women showed a decreased GI in comparison with Group A (59.389 vs 42.120). Women presented a greater average CAL than men as well as Group B vs Group A but without statistical significance. All biochemical markers were decreased respect to values of general population. Osteocalcin in GroupB women showed a statistically significant outcome vs GroupA (p=0.004). Acid phosphatase (total and tartrate-resistant) has a slight increase in Group B women versus Group A, and Beta-crosslap showed lower values in Group A men than Group B and slightly lower in Group A women versus Group B, without statistical significance. Conclusions Patients showed a slight to moderate degree of periodontal affectation, especially gingivitis related to bacterial plaque. Periodontal disorders tended to be more severe in Group B. While bone remodeling showed an overall decrease with greater affectation of bone neoformation phenomena, bone destruction tended to recover and normalize in time. Key words:Periodontal disease, dicoumarin, biochemical markers, bone remodeling.

Electron microprobe analysis in periodontal guided tissue regeneration.

Electron microprobe analysis was used to determine the evolution of Ca, P and S in regenerated tissue surrounding incisors roots after periodontal treatment with guided tissue regeneration. Our results, which showed increased Ca and P, and decreased S are discussed in relation to the process of mineralization electron probe microanalysis with potentially provided an accurate means of assessing the degree of mineralization in extremely small tissue samples.