Rafael Llamas

EDTA inhibits in vitro substrate adherence capacity of macrophages: Endodontic implications

The disodium salt of ethylenediamine tetraacetate (EDTA) is a calcium ion chelator used in endodontics to enlarge root canals. This study investigated the effect of EDTA on substrate adherence capacity of rat inflammatory macrophages to determine if EDTA leakage to periapical tissues during root canal therapy can alter macrophage function. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. Substrate adherence capacity assays were carried out in Eppendorf tubes for 15 min of incubation at 37 degrees C in a humidified atmosphere of 5% CO2. The adherence index (AI) was calculated. Results showed that EDTA decreased substrate adherence capacity of inflammatory macrophages in a time and dose-dependent manner. The lowest EDTA concentration that caused a significant inhibition of AI was 50 mM (p < 0.05), and the EDTA concentration that caused half-maximal inhibition (IC50) was 194 +/- 20 mM (p < 0.01). Calcium chloride (10 mM) increased the adherence index of macrophages by 17.1% (p < 0.05) and decreased the EDTA inhibitory effect on AI by 49.5% (p < 0.05). We conclude that an EDTA concentration lower than that used in endodontics decreased the substrate adherence capacity of macrophages significantly. Adhesion is the first step in the phagocytic process and in antigen presentation, but leakage of EDTA to periapical tissues during root canals preparation may inhibit macrophage function and reduce periapical inflammatory reactions.

The disodium salt of EDTA inhibits the binding of vasoactive intestinal peptide to macrophage membranes: Endodontic implications

The purpose of this study was to investigate the effect of the disodium salt of ethylenediamine tetraacetate (EDTA), a calcium ion chelator used in the root canal therapy, on vasoactive intestinal peptide (VIP) binding to macrophage membranes (MMs). Binding assays were conducted at 15 degrees C in 0.5 ml of 50 mM Tris-HCl buffer (pH 7.5) containing 1.6% (w/v) bovine serum albumin, 1.2 mg/ml of bacitracin, and different EDTA concentrations, using 45 pM of [125I]VIP as tracer. Results showed that EDTA inhibits VIP binding to MMs in a dose-dependent manner, with an IC50 value of 5.4 mM (p < 0.01). EDTA concentrations equal or higher than 100 mM of abolished VIP-MM interaction. Taking into account that the macrophage plays an essential role in inflammatory reactions and the immune response, we conclude that the apical extrusion of EDTA during root canal therapy could modify VIP-macrophage interaction modulating the inflammatory mechanisms involved in periapical lesions.

Critical Diameter of Apical Foramen and of File Size Using the Root ZX Apex Locator: An In Vitro Study

INTRODUCTION An evaluation was made of the accuracy of the Root ZX apex locator (J. Morita Corp, Tokyo, Japan) in widened foramina, considering the existing controversy over this issue in the literature. METHODS Ten single-root teeth were embedded in an alginate mold. The foramina were widened from 0.6 mm to 1.0 mm. The measurements were taken with all possible file sizes ≥#10. The statistical accuracy of the Root ZX was calculated for the different diameters and for the influence of file size. RESULTS The accuracy of the Root ZX apex locator with a range of error of ±0.5 mm was 87% in an apical foramen size of 0.6 mm and 84% using files size 45 or larger in an apical foramen size of 0.7 mm. With a tolerance of ±1 mm, the accuracy was 99% in an apical foramen size of 0.6 mm, 98% using files size 45 or larger in an apical foramen size of 0.7 mm, and 95% using files size 70 or larger in an apical foramen size of 0.8 mm. In the rest, accuracy was not certain. The measurements taken with smaller files were shorter. There were no cases of overestimation of the working length. CONCLUSIONS The Root ZX apex locator was accurate for an apical size of 0.6 mm, independently of the file size; between 0.7 to 0.8 mm, we should adjust the files to the foramen, whereas above size 0.9 mm the locator is not accurate. The results show that the accuracy of this electronic apex locator is gradually lost as the foramen widens. Considering the stable conditions of in vitro studies, our findings advise caution in clinical application of the locator.

Calcium Hydroxide Inhibits Substrate Adherence Capacity of Macrophages

The purpose of this study was to investigate the effect of calcium hydroxide on substrate adherence capacity of rat inflammatory macrophages to determine if calcium hydroxide can alter macrophage function. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. Substrate adherence capacity assays were carried out in Eppendorf tubes for 15 min of incubation at 37 degrees C in a humidified atmosphere of 5% CO2. The adherence index (AI) was calculated. Results showed that calcium hydroxide decreased substrate adherence capacity of inflammatory macrophages in a time and dose-dependent manner. The lowest calcium hydroxide concentration that caused a significant inhibition of AI was 1 mM (p < 0.05), and the concentration of calcium hydroxide that caused half-maximal inhibition (IC50) was 1.54 mM (p < 0.01). We conclude that calcium hydroxide decreased substrate adherence capacity of macrophages. When adhesion as the first step in the phagocytic process and in antigen presentation is taken into account, calcium hydroxide could inhibit macrophage function and reduce inflammatory reactions in periapical tissues or in dental pulp when it is used in root-canals therapy or in direct pulp capping and pulpotomy, respectively. Moreover, this effect could explain, at least in part, the mineralized tissue-inducing property of calcium hydroxide.

Taurodontism in premolars

Taurodontism is not a dental anomaly that affects only the molars. In a review of 379 premolars extracted for different pathologic reasons, three cases of taurodontism were found. The three cases were in upper premolars and were studied anatomically and radiographically. The literature was reviewed, as well as the low incidence of the condition in premolars, which is probably related to a genetic condition. Our observations support this fact, as suggested by the study of our cases from a restricted population nucleus, within a district area of the city of Seville, Spain. Among the diagnostic criteria of taurodontism, those established by Shifman and Chanannel are more objective. Finally, our findings support an embryologic origin as a result of a delay in the apical epithelial diaphragm evagination or by interference in the epitheliomesenchymatose induction.

Performance of Laser Fluorescence for Detection of Occlusal Dentinal Caries Lesions in Permanent Molars: An in vivo Study with Total Validation of the Sample

The objective of this in vivo study was to evaluate the performance of a laser fluorescence device in detecting dentinal caries in noncavitated occlusal surfaces. The sample included 102 first and second permanent molars, selected according to the criteria of Ekstrand et al. [Caries Res 1997;31:224–231]: 46 not suspected of having dentinal caries (score: 0–2) and 56 under suspicion (score: 3–4). Once measured by laser fluorescence, all were validated by fissurotomy (gold standard). To avoid ethical questions, the 46 teeth (score: 0–2) used were to serve as abutments for a fixed-fixed bridge. Visual inspection performed well, showing a sensitivity and specificity of 0.93 and 0.88, respectively. Laser fluorescence had an area under the receiver operating characteristic curve of Az = 0.85. The cutoff point with the highest sensitivity and specificity was 20, with a sensitivity and specificity of 0.89 and 0.75, respectively.

In Vitro Study of the Effect of Sodium Hypochlorite and Glutaraldehyde on Substrate Adherence Capacity of Macrophages

The purpose of this study was to investigate the in vitro effect of two irrigation solutions used in endodontics (5.25% sodium hypochlorite and 1% glutaraldehyde) on substrate adherence capacity of macrophages to determine if these substances can alter macrophage function. Inflammatory macrophages were obtained from Wistar rats and resuspended in RPMI-1640 medium. Substrate adherence capacity assays were carried out in Eppendorf tubes for 15 min of incubation at 37 degrees C in a humidified atmosphere of 5% CO2. The adherence index was calculated. Results showed that both sodium hypochlorite and glutaraldehyde significantly decreased the substrate adherence capacity of inflammatory macrophages. To take into account that adhesion is the first step in the phagocytic process of macrophages and in antigen presentation, sodium hypochlorite and glutaraldehyde could inhibit macrophage function and reduce inflammatory reactions in periapical tissues when they are used in root-canal therapy.

Case Report: Epignathus—Clinical, Radiologic, and Pathologic Considerations

In retrospect, a diagram could hace been made from the antenatal radiological examination of the case of epignathus presented here. The features of the epignathus are considered with respect to antenatal diagnosis and subsequent reparative surgery. Specific features such as axial organization, maturity of all tissues, and identical ossification points between host and parasite-all of which are evident in this case-favor the malformative origin of epignathi, thus distinguishing them from teratomata.

How to Diagnose Hidden Caries? The Role of Laser Fluorescence

The diagnosis of pits, grooves and fissures is one of the main challenges facing dentists in their professional activity, since the existence of an intact enamel surface may hide deep caries in dentin. Lesions of this kind were described by Weerheijm et al. (1992) as “hidden caries”. Over 70 years ago a high incidence of caries was confirmed in grooves and fissures (Hyat, 1923), in coincidence with more recent observations (Bragamian & Garcia-Godoy, 2009). In order to understand and explain this high incidence and the morphological peculiarities involved, it is essential to know the physiopathology of the tooth and of the carious lesion.