Effect of photodynamic therapy and non-thermal plasma on root canal filling: analysis of adhesion and sealer penetration

Objective The aim of this study was to evaluate the effect of photodynamic therapy (PDT) and non-thermal plasma (NTP) on adhesion and sealer penetration in root canals. Material and Methods Sixty single-rooted premolars were used. The teeth were prepared using a crown-down technique. NaOCl and EDTA were used for irrigation and smear layer removal, respectively. The root canals were divided into three groups: control, PDT, and NTP. After treatments, the roots were filled using gutta-percha and either AH Plus (AHP) or MTA Fillapex (MTAF) sealers. Samples were sectioned at 4, 8, and 12 mm from the apex (1-mm slices)and analyzed by the push-out bond strength test (adhesion) and confocal laser scanning microscopy (sealer penetration). Data were statistically evaluated using Kruskal-Wallis, Dunn’s, and Spearman’s tests. Results Regarding AHP, bond strength was similar in the NTP group and in the control group, but significantly lower in the PDT group. As to MTAF, both therapies showed lower values than the control group. In the confocal analysis of AHP, maximum and mean penetration, and penetrated area were statistically higher in the control group than in the PDT and NTP groups. Penetrated perimeter was similar among groups. Regarding MTAF, all parameters yielded better results in the NTP than in the control group. The PDT and control groups showed similar results except for penetrated area. Conclusion PDT and plasma therapy affected the adhesion and sealer penetration of root canals filled with AH Plus and MTA Fillapex and there is no positive correlation between adhesion and sealer penetration

Studies of metal binding and enzyme inhibition by salivary histatin 5

PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact [email protected] (D.Sc.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 2000 (Oral Biology).Includes bibliographical references (leaves 176-192).Histatins are small histidine-rich salivary polypaptides, which exhibit antimicrobial activity against Candida ablicans. This anti-microbial activity has been ascribed in part to a high content of basic amino acids. However, unlike most other antimicrobial proteins histatins have a relatively high content of histidines, tyrosines and acidic amino acids, which participate in metal ion coordination. Therefore, the first aim of this investigation was to determine whether histatins could associate with metal ions, which are known to be present in salivary secretions and whole saliva. In a spectrophotometric competition assay using the metalochromic indicator murexide, it was found that histatin 3 and histatin 5 dissociated complexes of murexide with zinc and copper. Complexes with nickel and cobalt were also dissociated, but to a lesser extent. In similar experiments, it was found that histatin 1, histatin 3 and histatin 5 were able to dissociate complexes of methylthymol blue with calcium and magnesium. Physical binding parameters and spectral properties of zinc- and copper-histatin complexes were investigated to obtain direct evidence of these interactions. Absorption spectra of histatin 5 at increasing copper chloride concentrations resulted in higher absorbance in the 230 to 280 m wavelength range and this spectral change was saturated at a peptide:metal molar ratio of approximately 1:1. A corresponding band was observed in the visible range of the spectrum with an absorbance maximum and molar extinction coefficient corresponding to that of a well known copper binding motif (ATCUN: Asp-Ser-His). Quantitative assessment of zinc and copper binding to histatin 5 using isothermal titration calorimetry revealed at least one high affinity site for zinc and copper, with binding constants of 1.2 x 10[superscipt 5] and 2.6 x 1O[superscript 7] M[superscript -1], respectively. These results indicate that histatin 5 exhibits metallopeptide-like properties. The biological significance of this property could be that histatins contribute to salivary metal binding capacity or interfere with biomolecules that require metals as co-factors. [TRUNCATED

Effect of photodynamic therapy and non-thermal plasma on root canal filling: analysis of adhesion and sealer penetration

Abstract Objective The aim of this study was to evaluate the effect of photodynamic therapy (PDT) and non-thermal plasma (NTP) on adhesion and sealer penetration in root canals. Material and Methods Sixty single-rooted premolars were used. The teeth were prepared using a crown-down technique. NaOCl and EDTA were used for irrigation and smear layer removal, respectively. The root canals were divided into three groups: control, PDT, and NTP. After treatments, the roots were filled using gutta-percha and either AH Plus (AHP) or MTA Fillapex (MTAF) sealers. Samples were sectioned at 4, 8, and 12 mm from the apex (1-mm slices)and analyzed by the push-out bond strength test (adhesion) and confocal laser scanning microscopy (sealer penetration). Data were statistically evaluated using Kruskal-Wallis, Dunn’s, and Spearman’s tests. Results Regarding AHP, bond strength was similar in the NTP group and in the control group, but significantly lower in the PDT group. As to MTAF, both therapies showed lower values than the control group. In the confocal analysis of AHP, maximum and mean penetration, and penetrated area were statistically higher in the control group than in the PDT and NTP groups. Penetrated perimeter was similar among groups. Regarding MTAF, all parameters yielded better results in the NTP than in the control group. The PDT and control groups showed similar results except for penetrated area. Conclusion PDT and plasma therapy affected the adhesion and sealer penetration of root canals filled with AH Plus and MTA Fillapex and there is no positive correlation between adhesion and sealer penetration

Antimicrobial efficacy of the EndoVac system plus PDT against intracanal Candida albicans: an ex vivo study

This study evaluated the ex vivoantimicrobial efficacy of the EndoVac system and the photodynamic therapy (PDT) associated with chemomechanical debridement (CMD) and intracanal medication on Candida albicans. Seventy-eight sterile premolars were contaminated withC. albicans (ATCC 21433) for 30 days. The teeth were randomly assigned into four groups: Control (CMD with conventional irrigation); Endovac (CMD with EndoVac system); PDT (CMD with conventional irrigation and PDT); and Endovac + PDT (CMD with EndoVac and PDT). After the therapies, intracanal dressing (calcium hydroxide) was applied to all teeth for seven days. Samples were obtained before (T1) and after the therapeutic procedures (T2), and after intracanal medication (T3), plated onto BHI agar and incubated (37°C, 48 h) to determine the colony-forming units (CFU)/mL. The overall mean level ofC. albicans at baseline was relatively high (1.85 x 106 ± 2.7 x 106 CFU mL-1). A significant reduction of C. albicans(p < 0.05) was observed over time (T1 to T2 and T1 to T3) in all groups. An additional significant reduction from T2 to T3 was observed only in the Endovac group (p < 0.05). No differences in mean reduction of C. albicans were observed among groups. However, the Endovac group presented the lowest mean counts of C. albicans at T3, whereas the PDT group had the highest counts of this microorganism (p < 0.05). The EndoVac system of irrigation/aspiration associated with CMD was the most effective therapeutic protocol for reducing intracanal levels of C. albicans. PDT showed a very limited efficacy against this species

The use of auxiliary devices during irrigation to increase the cleaning ability of a chelating agent

Objectives This study investigated the cleaning ability of ultrasonically activated irrigation (UAI) and a novel activation system with reciprocating motion (EC, EasyClean, Easy Equipamentos Odontológicos) when used with a relatively new chelating agent (QMix, Dentsply). In addition, the effect of QMix solution when used for a shorter (1 minute) and a longer application time (3 minutes) was investigated. Materials and Methods Fifty permanent human teeth were prepared with K3 rotary system and 6% sodium hypochlorite. Samples were randomly assigned to five groups (n = 10) according to the final irrigation protocol: G1, negative control (distilled water); G2, positive control (QMix 1 minute); G3, QMix 1 minute/UAI; G4, QMix 1 minute/EC; G5, QMix 3 minutes. Subsequently the teeth were prepared and three photomicrographs were obtained in each root third of root walls, by scanning electron microscopy. Two blinded and pre-calibrated examiners evaluated the images using a four-category scoring system. Data were statistically analyzed using Kruskal-Wallis and Dunn tests (p < 0.05). Results There were differences among groups (p < 0.05). UAI showed better cleaning ability than EC (p < 0.05). There were improvements when QMix was used with auxiliary devices in comparison with conventional irrigation (p < 0.05). Conventional irrigation for 3 minutes presented significantly better results than its use for 1 minute (p < 0.05). Conclusions QMix should be used for 1 minute when it is used with UAI, since this final irrigation protocol showed the best performance and also allowed clinical optimization of this procedure

Influence of retreatment in the formation of dentinal microcracks in mandibular molars filled with a calcium silicate based sealer

Introduction: In endodontically treated teeth, dentinal defects such as microcracks can progress to a vertical root fracture and lead to tooth loss. Objective: The present study aimed to evaluate, by micro-computed tomography analysis, the formation of dentinal microcracks during filling removal in endodontic retreatment of root canals filled with gutta-percha and Total Fill BC bioceramic sealer. Methods: Twenty mesial roots of mandibular molars were instrumented and obturated with gutta-percha and Total Fill BC sealer and then the filling material was removed with rotary Protaper Retreatment files. The specimens were scanned before instrumentation, after filling and after retreatment. The transversal images obtained after filling were compared with the images obtained after removal of the filling material. A descriptive statistical analysis was performed. Results: Among the 24.444 cross-sections analyzed, 5.67% presented some type of dentinal defect, with 0.51% in the initial images, 2.58% in the post-filling images and 2.58% in the post-retreatment images. All the dentinal defects identified in the images obtained after the retreatment were already present in the corresponding images after the filling. New dentinal microcracks were not observed after removal of the filling material. Conclusion: Retreatment of mesial roots of mandibular molars filled with a silicate-based root canal filling material do not influence the formation of dentinal microcracks

Effect of a sonic device on bonding of fiberglass posts to root canals

is study evaluated the effect of a sonic device on the bonding of fiberglass posts cemented with a self-etching adhesive combined with conventional cement or a self-adhesive cement to root dentin. Methods: Forty single-rooted bovine incisors were endodontically prepared using a step-back technique. Gutta-percha and AH Plus sealer were used for root canal filling, combined with a thermoplasticization technique. After 1 week, the post space was prepared and the roots were divided into four groups according to the following factors: adhesive system/resin cement (Ambar/ AllCem Core [FGM] and RelyX U200 [3M]) and application mode (manual or sonic). The posts were cemented and the roots were cut into discs and submitted to push-out bond strength (POBS) test. The failure mode was evaluated using a stereoscope at 25x magnification. The data were analyzed statistically using ANOVA and Tukeys post-hoc test (&#945; = 0.05). Results: The sonically activated RelyX U200 group was superior to the other groups. RelyX U200 manually applicated showed similar results to those of sonically activated Âmbar/AllCem. These three groups outperformed the Âmbar/AllCem manually applicated group. Adhesive failure between dentin and resin cement was the most predominant pattern. Conclusion: Sonic application of self-etching adhesive and self-adhesive cement improved the POBS of fiber posts to the root canal