Alberto Dagna

Protective effect on enamel demineralization of a CPP-ACP paste: an AFM in vitro study

OBJECTIVES The aim of the present in vitro study was the evaluation of a CPP-ACP paste (Tooth Mousse) on preventing dental erosion produced by a soft drink (Coca Cola), using Atomic Force Microscopy (AFM). METHODS Thirty extracted human central incisors free of caries were selected and divided in a treatment and a control half. The treatment halves were divided in three groups-group 1: demineralization with soft drink (4 intervals of 2 min); group 2: demineralization with soft drink (4 intervals of 2 min) plus Tooth Mousse; group 3: intact enamel plus Tooth Mousse. In groups 2 and 3 Tooth Mousse was applied for 3 min at 0, 8, 24 and 36 h. The surface of each specimen was imaged by AFM and R(rms) values were registered. RESULTS Among treatment specimens of groups 1 and 2, a statistically significant difference (P<0.01) in R(rms) values was registered: treatment of the specimens with CPP-ACP paste had a protective effect on enamel demineralization. In group 3 no statistically significant difference was registered between exposed and not exposed halves of the specimens. CONCLUSIONS The use of a CPP-ACP paste had a protective effect on enamel demineralization in an in vitro model.

Cytocompatibility and Antibacterial Properties of Capping Materials

The aim of this study was to evaluate and compare the antimicrobial activity and cytocompatibility of six different pulp-capping materials: Dycal (Dentsply), Calcicur (Voco), Calcimol LC (Voco), TheraCal LC (Bisco), MTA Angelus (Angelus), and Biodentine (Septodont). To evaluate antimicrobial activity, materials were challenged in vitro with Streptococcus mutans, Streptococcus salivarius, and Streptococcus sanguis in the agar disc diffusion test. Cytocompatibility of the assayed materials towards rat MDPC-23 cells was evaluated at different times by both MTT and apoptosis assays. Results significantly differed among the different materials tested. Both bacterial growth inhibition halos and cytocompatibility performances were significantly different among materials with different composition. MTA-based products showed lower cytotoxicity and valuable antibacterial activity, different from calcium hydroxide-based materials, which exhibited not only higher antibacterial activity but also higher cytotoxicity.

Photoactivated disinfection (PAD) in endodontics: an in vitro microbiological evaluation

Purpose The objective of the present study was the in vitro evaluation by MTT test of the antimicrobial effect of photoactivated disinfection (PAD) and, comparatively, of a conventional 5.25% NaOCl irrigating solution. Methods Enterococcus faecalis, Streptococcus mutans and Streptococcus sanguis strains were selected for the test. Freshly extracted single-rooted human teeth were endodontically treated, inoculated with bacterial strains and then divided into different groups, each of them treated with PAD, with PAD plus 0.5% NaOCl solution, with TBO, with PAD for longer time and with 5% NaOCl solution (positive control). Results The results were significantly different among the various groups, and for Enterococcus faecalis, Streptococcus mutans and Streptococcus sanguis. PAD applied for a longer time (in respect to manufacturers instructions) or PAD associated to 5% NaOCl showed the significantly higher antibacterial effects.

Surface roughness of flowable resin composites eroded by acidic and alcoholic drinks

Aim: The aim of this study is to evaluate the surface roughness of four flowable resin composites following exposure to acidic and alcoholic drinks. Materials and Methods: SureFil SDR flow, TetricEvoFlow, Esthet-X Flow and Amaris Flow HT samples were immersed in artificial saliva, Coca Cola and Chivas Regal Whisky. Each specimen was examined using a Leica DCM 3D microscope: Arithmetical mean height of the surface profiles was measured (Sa). Results: Kruskal-Wallis test showed significant differences among various groups (P<0,001). Mann Whitney test was applied and control groups showed significantly lower Sa values than other groups (P=0,008). Coca Cola groups showed highest Sa values (P<0,021). No significant differences (P=0,14) in surface texture were found among the specimens of the different materials. No significant differences were found among TetricEvoFlow, Esthet-X Flow and Amaris Flow under control conditions nor after Coca Cola application. Under control condition and after Coca Cola application SureFil SDR flow showed significantly higher Sa values. Moreover, after whisky application Amaris Flow showed significantly lower Sa values then the other three groups that showed no significant differences among them. Conclusions: Acidic and alcoholic drinks eroded the surface roughness of all evaluated flowable resin composites.

In vitro cytotoxicity evaluation of different pulp capping materials: a comparative study.

Abstract Direct pulp capping covers the exposed surface of the pulp to maintain its vitality and preserve its functional and biologic activity. The aim of the present study was to compare the biocompatibility effects of seven different pulp-capping materials in vitro: Dycal®, Calcicur®, Calcimol LC®, TheraCal LC®, ProRoot MTA®, MTA-Angelus®, and Biodentine®. Using the Transwell insert methodology by Alamar blue test, we evaluated the cytocompatibility of the above mentioned materials towards murine odontoblasts cells (MDPC-23) at three different times (24, 48, and 72 h). For additional control, the cell viability at 72 hours was also assessed by MTT assay. Morphological analysis of murine odontoblasts was assessed by Confocal Laser Scanning Microscope. The results indicate significantly different biocompatibility among materials with different composition. Biodentine® and mineral trioxide aggregate (MTA)-based products showed lower cytotoxicity, varying from calcium hydroxide-based materials, which exhibited higher cytotoxicity. Although our findings are limited to in vitro conditions, the observation that Biodentine® caused a cytotoxic effect similar to MTA suggests that it may be considered an alternative in pulp-capping treatment, as calcium hydroxide-based materials present higher cytotoxic effects.

Cyclic fatigue resistance of OneShape, Reciproc, and WaveOne: An in vitro comparative study

Aims: The aim of this in vitro study was to evaluate the cyclic fatigue resistance of three single-use nickel–titanium (NiTi) instruments. Materials and Methods: Forty files each of OneShape (OS), Reciproc R25 (R25), WaveOne Primary (WO) file, and ProTaper (PT) F2 (as control) were tested in four curved artificial canals with different angles and radii of curvature. The number of cycles to fracture (NCF) was determined and the data were compared for differences by using two-way analysis of variance (P < 0.05). Results: In general, all single-use instruments were more resistant than traditional rotary instrument used as control. R25 showed the highest cyclic fatigue resistance. One Shape and WO files showed similar cyclic fatigue resistance values, higher than PT F2. Conclusions: Within the limitations of this study, it can be concluded that R25 was the most fatigue resistant. OS rotary instruments seem to have good mechanical resistance, similar to NiTi files developed for reciprocating motion.

Antibacterial efficacy of conventional and single-use Ni-Ti endodontic instruments: An in vitro microbiological evaluation

Purpose The purpose of this in vitro study was to investigate the capability of different Ni-Ti instruments in disinfecting root canals previously infected with E. faecalis. Methods 60 single-rooted, freshly extracted teeth were selected, sterilized and inoculated with cells of E. faecalis strain. All root canals were shaped with different Ni-Ti instruments (MTwo, Revo-S, Reciproc, and OneShape) under irrigation with NaOCl and 17% EDTA solutions by the same trained operator. The number of Colony Forming Units (CFU)/ml of E. faecalis was evaluated for each group. Numeric data were submitted to statistical analysis. Results MTwo, REVO-S, Reciproc and OneShape reported significantly lower CFU/ml values and showed no significant differences among them (p>0.05). All groups showed significantly higher CFU/ml values than not treated samples (negative control). Conclusions All the Ni-Ti instrumentation efficiently reduced E. faecalis counts and no significant differences were found among them. Single-use files can offer antibacterial results comparable with traditional instruments.

Decalcifying effect of different ethylenediaminetetraacetic acid irrigating solutions and tetraclean on root canal dentin.

INTRODUCTION The objective of this study was to evaluate and compare in vitro the decalcifying capability on root canal dentin of 4 different irrigating solutions. METHODS Twenty-five freshly extracted maxillary central incisors were selected. The canals were prepared to obtain a total of 4 samples from each root. The samples were randomly divided into 5 equal experimental groups (n = 20) according to the irrigating solutions tested (Tetraclean, Largal Ultra, 17% ethylenediaminetetraacetic acid, Tubuliclean). For each irrigating solution, the specimens were immersed for 5, 10, and 15 minutes. After exposures, the concentration of Ca(2+) extracted was measured by inductively coupled plasma-atomic emission spectrometry. Data were analyzed by means of nonparametric tests, and statistical analysis was performed. RESULTS The higher release of Ca(2+) was observed in samples treated with Tetraclean; this citric acid-based agent showed significantly higher decalcifying capability. For all irrigating solutions tested, 10 minutes of application are sufficient to obtain the maximum Ca(2+) release. CONCLUSIONS The results indicated that Tetraclean could be applied to obtain more efficient removal of the smear layer and to facilitate the biomechanical instrumentation procedures.

In vitro evaluation of antimicrobial efficacy of endodontic irrigants

Purpose The objective of this study was to compare in vitro, by MTT assay, the antimicrobial efficacy of Niclor 5 (5% NaOCl solution), Cloreximid (0.2% chlorhexidine and 0.2% cetrimide solution), 3% hydrogen peroxide and 17% EDTA against two microorganisms associated with primary endodontic infections. Methods Enterococcus faecalis and Streptococcus mutans strains were selected for this test. Freshly extracted single-rooted human teeth were endodontically treated, inoculated with bacterial strains and then divided into different groups, each of them rinsed with Niclor 5 (5% NaOCl solution), Cloreximid (0.2% chlorhexidine and 0.2% cetrimide solution), 3% hydrogen peroxide, 17% EDTA and with 5% NaOCl solution (positive control). Results Even though all the tested irrigating solutions demonstrated antibacterial effects against E. faecalis and S. mutans, the results were significantly different between the various groups. The greatest antimicrobial effects were observed in groups treated with 5% NaOCl and 17% EDTA. Interestingly, the effectiveness of EDTA could be ascribed to its capability of detaching biofilm from canal walls.

SEM evaluation of the root canal walls after treatment with tetraclean

Purpose In this ex vivo study, the surface cleanliness of root canal walls after shaping with Ni-Ti instruments and irrigating with different endodontic solutions was evaluated by SEM. Methods 50 single-rooted teeth were divided into 5 groups. All root canals were shaped with Revo-S™ (MICRO-MEGA®, Besancon, France) rotary Ni-Ti instruments and irrigated with NaOCl, varying the final rinse: NaOCl, Tetraclean, 17% EDTA, Cloreximid, Tetraclean liquid not mixed with powder. Specimens were fractured longitudinally and prepared for SEM analysis in order to evaluate the presence/absence of smear layer and the presence/absence of open tubules at the coronal, middle, and apical third of each canal, using a 3-step scale for scores. Numeric data were analyzed using Kruskall-Wallis test and Mann-Whitney U test and significance was predetermined at p<0.05. Results This study showed significant differences between the various groups. The 5.25% NaOCl + Tetraclean and 5.25% NaOCl + 17% E.D.T.A. groups had significantly lower scores than other groups (p<0.001), with no significant difference between them. Conclusions Final rinse with Tetraclean is effective in removing the smear layer, leaving a high number of opened dentin tubules.