Candida albicans adhesion on 3D-printed and thermopolymerizable polymethyl methacrylate for removable prostheses.

PURPOSE: To compare Candida albicans adhesion and quantify the biofilm formed on thermopolymerizable (T.PMMA) and 3D printing (3D.PMMA) polymethyl methacrylate through quantitative and qualitative analyses. METHODS: The specimens were made (n= 39/material) by conventional polymerization (T.PMMA) and designed in Autodesk Meshmixer software, followed by 3D printing (3D.PMMA) - CAD-CAM method. After the roughness standardization, the monospecies biofilm of C. albicans (ATCC 10231) was submitted to adhesion analysis, verifying the quantification and microbial load, in triplicate, by the methods of counting colony forming units (CFU/mL) and staining with crystal violet, followed by optical density reading, respectively. Qualitative analyses were performed by scanning electron microscopy to analyze the surface characteristics of the specimens and biofilm formed. The Mann-Whitney U test was used for comparisons between resins regarding the count of CFU/mL (log¹°+ 1) and optical density values (P≤ 0.05). RESULTS: T.PMMA (5.78 ± 0.43) had a CFU/mL count (P< 0.001) higher than 3D.PMMA (4.84 ± 0.39). There was a difference between C. albicans biofilm accumulation (P< 0.001), in which on T.PMMA (1.59 ± 0.31) was higher than 3D.PMMA (1.10 ± 0.14). The qualitative analyses corresponded to the quantitative ones and allowed the visualization of more porosities in T.PMMA. CLINICAL SIGNIFICANCE: The adhesion (microbial load and biofilm accumulation) of C. albicans was lower in the 3D printed polymethyl methacrylate when compared to the thermopolymerizable model.

Age and experience with dental operating microscope: Do these factors influence on the post space preparation and adhesion of glass fiber posts?

This study evaluated the influence of operator's age and experience with dental operating microscope (DOM) on the cleaning of post space walls and on bond strength of glass fiber posts associated with self-adhesive resin cement. Sixty bovine roots were selected. Root canal preparation was performed and roots were filled using gutta-percha/AH Plus. For post space preparation, specimens were divided into four groups (n = 15), according to operator's age and the use of DOM: (1) ≥40 years; (2) ≥40 years with magnification; (3) <40 years; (4) <40 years with magnification. Next, a high-speed bur of the post system and torque-controlled round burs were used for cleaning of post space. Five roots in each group were evaluated for the degree of cleanliness under a stereo microscope using a scoring system. In the remaining 10 specimens from each group, glass fiber posts were cemented with RelyX U200. Two slices (1 ± 0.1 mm) prepared on each root third of all specimens were evaluated by push-out analysis. The scoring system was analyzed using Kruskal-Wallis and push-out data using ANOVA. Significance level was set at 5%. No significant difference was observed in cleaning scores among groups (p > .05). There was no significant difference when comparing the groups and the root thirds (p > .05). The adhesive failure between dentin, cement, and post predominated in all groups. Operator's age and experience with DOM did not influence the cleanliness of root canal walls or the bond strength of glass fiber posts associated with self-adhesive resin cement for post space preparation. RESEARCH HIGHLIGHTS: Although magnification is considered part of Endodontics, little is known about the variables associated. Operator's age and experience with microscope on cleaning of canals and on push-out of posts with self-adhesive resin cement were evaluated.

Clinical Investigation of Microbial Profile and Levels of Endotoxins and Lipoteichoic Acid at Different Phases of the Endodontic Treatment in Teeth with Vital Pulp and Associated Periodontal Disease.

INTRODUCTION: The aim of this in vivo study was to investigate the microbial profile as well as the levels of lipopolysaccharide (LPS) and lipoteichoic acid (LTA) at different phases of endodontic treatment in teeth with vital pulp and associated periodontal disease. METHODS: Ten patients were selected for this clinical study. Samples were taken from periodontal pockets (PPs) and root canals (RCs) using sterile paper points before and after chemomechanical preparation and after intracanal medication. For microbiological analysis, nested polymerase chain reaction and checkerboard DNA-DNA hybridization were used. Levels of LPS and LTA were assessed using limulus amebocyte lysate and enzyme-linked immunosorbent assays, respectively. Data were statistically analyzed at a significance level of 5%. RESULTS: Bacterial DNA from 17 of the 17 species investigated was detected in samples of PPs, whereas 6 of the 17 species were not present in the initial samples of RCs using nested polymerase chain reaction. In the initial samples, 38 of 40 probes were detected in PPs, whereas 12 of 40 probes were detected in RCs using checkerboard DNA-DNA hybridization. Overall, endodontic procedures were efficient in modifying the microbiota of PPs and RCs. Levels of LPS and LTA were reduced after the endodontic procedures, although higher concentrations of both had been found in PPs compared with RCs. CONCLUSIONS: The microbiota of PPs and RCs in teeth with vital pulp and associated periodontal disease is polymicrobial, with the presence of gram-negative, gram-positive, facultative, and strict anaerobes. Chemomechanical preparation and calcium hydroxide-based intracanal medication allowed the reduction of infectious content in both sites.

Periodontal and endodontic infectious/inflammatory profile in primary periodontal lesions with secondary endodontic involvement after a calcium hydroxide-based intracanal medication.

OBJECTIVE: The aim of the present study was to investigate the effects of a calcium hydroxide-based intracanal medication (ICM) on periodontal and endodontic infectious/inflammatory contents and on periodontal clinical parameters in teeth with primary periodontal lesion and secondary endodontic involvement. MATERIALS AND METHODS: Ten patients with abnormal pulp test results and deep probing depth derived from primary periodontal disease with secondary endodontic involvement were included. Samples were collected from root canals (RC) and periodontal pockets (PP) in order to investigate the microbiological status, levels of endotoxin (LPS), cytokines, and matrix metalloproteinases (MMP), before and after ICM. PCR was used for microbiological assessment. The kinetic-chromogenic LAL assay was used for LPS quantification. Quantikine ELISA kits were used for measurement of IL-1 α, IL-1 ß, TNF-α, PGE2, MMP-2, MMP-3, MMP-8, MMP-9, and MMP-13 levels. The statistical analyses were made using the Friedman and Wilcoxon tests (p < 0.05). T test was used to compare data on periodontal characteristics. RESULTS: ICM did not reduce the number of microorganisms in PP and RC, except for Fusobacterium nucleatum in RC. There was a significant reduction in LPS, MMPs, IL-1 ß, and TNF-α levels in PP after ICM. In RC, LPS, MMP13, PGE2, and IL-1ß levels remained unaltered (p > 0.05); however, the levels of the other MMPs and cytokines were reduced (p < 0.05). After 1 year of the root canal treatment, tooth mobility was significantly reduced (p ≤ 0.05). CONCLUSIONS: The use of a calcium hydroxide-based ICM showed positive effects for periodontal treatment prognosis, as it reduced LPS, cytokine, and MMP levels in periodontal pockets. CLINICAL SIGNIFICANCE: Patients presenting deep probing depth and undergoing periodontal treatment for at least 6 months, with no positive response to periodontal therapy, might benefit with the endodontic treatment.