Mauricio Pierdant-Pérez

Eugenol Toxicity in Human Dental Pulp Fibroblasts of Primary Teeth

OBJECTIVE The aim of the study was to determine the eugenol concentrations at which toxicity occurs in human dental pulp fibroblasts of primary teeth. STUDY DESIGN Samples of primary dental pulp tissue were taken. Tissue samples were seeded by means of explant technique and used in the 4(th)-5th pass. Single Cell Gel Electrophoresis (Comet), phenazine MeThoSulfate (MTS), LIVE/DEAD Cell Viability/Toxicity and trypan blue assays for evaluation of the cytotoxicity of increasing concentrations of eugenol (0.06 to 810 μM) were performed. RESULTS The results of toxicity tests showed toxic effects on dental pulp fibroblasts, even at very low concentrations of eugenol (0.06 μM). Very low concentrations of eugenol produce high toxicity in human dental pulp fibroblasts. CONCLUSIONS All of the concentrations of eugenol that we evaluated produced high toxicity in human dental pulp fibroblasts of primary teeth.

Pain Measurement through Temperature Changes in Children Undergoing Dental Extractions

Background and Objective. Pain evaluation in children can be a difficult task, since it possesses sensory and affective components that are often hard to discriminate. Infrared thermography has previously been used as a diagnostic tool for pain detection in animals; therefore, the aim of this study was to assess the presence of temperature changes during dental extractions and to evaluate its correlation with heart rate changes as markers of pain and discomfort. Methods. Thermographic changes in the lacrimal caruncle and heart rate measurements were recorded in healthy children scheduled for dental extraction before and during the procedure and compared. Afterwards, correlation between temperature and heart rate was assessed. Results. We found significant differences in temperature and heart rate before the procedure and during the dental extraction (mean difference 4.07°C, p < 0.001, and 18.11 beats per minute, p < 0.001) and no evidence of correlation between both measurements. Conclusion. Thermographic changes in the lacrimal caruncle can be detected in patients who undergo dental extractions. These changes appear to be stable throughout time and to possess very little intersubject variation, thus making them a candidate for a surrogate marker of pain and discomfort. Future studies should be performed to confirm this claim.

Zinc Oxide−Eugenol Pulpotomy in Primary Teeth: A 24-Month Follow-up

OBJECTIVE The purpose of the present study was to evaluate the clinical and radiographic effectiveness of zinc oxide-eugenol (ZOE) as the only pulp capping agent in pulpotomies carried out on decayed primary molars after a follow-up period of 24 months. STUDY DESIGN In total, 60 pulpotomies were performed on 38 patients aged 3 to 11 years. Pulpotomy treatment consisted of the removal of the coronal pup tissue, subsequent hemostasis, irrigation with saline solution, drying and pressure with sterile cotton pellets, and placement of a thick regular ZOE base with a minimal amount of eugenol directly over the vital radicular pulp. Additionally, a histopathologic study was carried out on some of the molars treated. RESULTS After a 24-month follow-up, we considered 51 procedures to be successful and 9 failures using clinical and radiographic criteria; most of the failures occurred between the 12th and 18th month. CONCLUSIONS Results suggest that the proposed pulpotomy treatment with ZOE as the only capping agent may be considered as an alternative technique in the pulp treatment of primary molars.

Oral mucosa: an alternative epidermic cell source to develop autologous dermal-epidermal substitutes from diabetic subjects

Abstract Oral mucosa has been highlighted as a suitable source of epidermal cells due to its intrinsic characteristics such as its higher proliferation rate and its obtainability. Diabetic ulcers have a worldwide prevalence that is variable (1%-11%), meanwhile treatment of this has been proven ineffective. Tissue-engineered skin plays an important role in wound care focusing on strategies such autologous dermal-epidermal substitutes. Objective The aim of this study was to obtain autologous dermal-epidermal skin substitutes from oral mucosa from diabetic subjects as a first step towards a possible clinical application for cases of diabetic foot. Material and Methods Oral mucosa was obtained from diabetic and healthy subjects (n=20 per group). Epidermal cells were isolated and cultured using autologous fibrin to develop dermal-epidermal in vitro substitutes by the air-liquid technique with autologous human serum as a supplement media. Substitutes were immunocharacterized with collagen IV and cytokeratin 5-14 as specific markers. A Student´s t- test was performed to assess the differences between both groups. Results It was possible to isolate epidermal cells from the oral mucosa of diabetic and healthy subjects and develop autologous dermal-epidermal skin substitutes using autologous serum as a supplement. Differences in the expression of specific markers were observed and the cytokeratin 5-14 expression was lower in the diabetic substitutes, and the collagen IV expression was higher in the diabetic substitutes when compared with the healthy group, showing a significant difference. Conclusion Cells from oral mucosa could be an alternative and less invasive source for skin substitutes and wound healing. A difference in collagen production of diabetic cells suggests diabetic substitutes could improve diabetic wound healing. More research is needed to determine the crosstalk between components of these skin substitutes and damaged tissues.

Amoebic toxic colitis: analysis of factors related to mortality

Abstract Background: Toxic or fulminant colitis due to Entamoeba histolytica infrequently presents but is very serious. Unfortunately, there are numerous contradictory factors related to mortality. Methods: We analyzed several cases of E. histolytica infection to determine the factors related to mortality. We included patients >15 years of age who were histopathologically diagnosed with amoebic toxic colitis and treated from January 2000 through December 2006. We evaluated demographic, clinical, laboratorial, surgical, and histopathological characteristics. Results: We examined 24 patients and recorded 12 deaths (50%). Twenty patients underwent surgery within a mean time of 24 hours (range: 8–120 hours). Tenesmus and intestinal perforation were determined to be statistically significant (P<0·05) by univariate analysis. Three models of logistic regression were able to determine three statistically significant factors that affected mortality: (1) tenesmus and a lymphocyte count <1·5×103 cell/μl; 2) depth of invasion beyond the mucosa and a lymphocyte count <1·5×103 cell/μl; 3) time spent with symptoms and perforation. Conclusions: The mortality rate determined in this study is similar to previously reported series. A low lymphocyte count, significant depth of invasion, and intestinal perforation were determined to be the factors related to increased mortality, while tenesmus and limited amount of time spent with symptoms were associated with survival. Quick diagnosis and appropriate treatment are important factors that reduce mortality.

Effects of Local Use of Insulin on Wound Healing in Non-diabetic Patients:

Background: Clinical trials have shown the positive effects of local insulin therapy in the formation of new vessels and fibrosis in acute and chronic diabetic wounds without major adverse effects. Objective: The aim of this study was to investigate the effects of local insulin use on wound healing in non-diabetic patients. Methods: A randomized, split-plot, double-blind, placebo-controlled trial was conducted. Ten non-diabetic patients with full-thickness acute wounds were recruited (5 due to trauma, 3 to burns, and 2 to pressure). All wounds received standard bedside treatment. Each wound was divided into 2 zones. One side received a standard care plus insulin, while the other received standard care plus injection of saline solution. A biopsy specimen was taken from both sites on days 0 and 14. The amount of blood vessel growth and the percentage of fibrosis were evaluated. Results: A significant difference in the number of new vessels was observed on the insulin-treated site (70.6 [29.21]) compared to saline only (26.5 [34.3]; P < .04). The percentage of fibrosis (insulin 34.7 [28.02] vs saline 27.8 [29.9]) showed no significant difference. No adverse events related to the study occurred. The clinical implications of this study are considerable in terms of the formation of blood vessels but not fibrosis. Conclusion: We suggest that local insulin administration is a safe therapeutic option for angiogenesis in wounds of non-diabetic patients.

Effect of Silver Nanoparticle-Added Pit and Fissure Sealant in the Prevention of Dental Caries in Children

OBJECTIVE The objective of this study was to evaluate the effects of pit and fissure sealant mixed with silver nanoparticles on dental caries, by means of monthly measurement of fluorescence with DIAGNOdent over six months. STUDY DESIGN This study was divided in two phases: experimental and clinical. In the experimental phase, the adhesion and microleakage of the pit and fissure sealant experiment were evaluated. Two groups of 10 teeth, without serious carious lesions, were included. Conventional (group A) and silver nanoparticles (group B) were added to the pit and fissure sealant. For the clinical phase, a split-mouth study was performed on 40 children aged 6-10 years old with healthy, erupted permanent first molars. A conventional pit and fissure sealant or a silver nanoparticle-mixed sealant was randomly placed. Repeated measures analysis was performed. RESULTS Conventional sealant presented an average microleakage of 30.6%, and the silver nanoparticle-mixed sealant showed 33.6% (P=NS). A three times greater reduction in fluorescence was found in the silver nanoparticles group compared to the conventional group (P<0.05). No sex- or age-based associations were found. CONCLUSIONS The silver nanoparticle-mixed sealant reduced tooth demineralization significantly and likely increased remineralization, compared to the conventional sealant.