Εργαστηριακή μελέτη ρητινωδών υλικών επικάλυψης σύνθετων ρητινών (composite surface sealers)

Abstract

SUMMARY In vitro evaluation of composite surface sealers Μaria Anagnostou , DDS, MS, DrMedPhD Candidate, Department of Operative Dentistry, University of Athens, School of DentistryObjectives: The aim of the present study was to evaluate the chemical, mechanical, surface and biological properties of composite surface sealers (CSS) with different monomer composition. The null hypothesis was that no statistically significant differences exist among the CSS in the properties tested.Representative, regarding molecular composition, products of CSS were chosen. Products tested were Biscover LV (BC) (Bisco, Inc., Schaumburg, IL, USA), DuraFinish (DF) (Parkell, Inc., Edgewood, NY, USA), G-Coat Plus (GC) (GC Corporation, Tokyo, Japan) and PermaSeal (PS) (Ultradent Products, Inc., S. Jordan, UT, USA). Materials and methods: In vitro evaluation included analysis of chemical composition of monomers contained in CSS products, evaluation of curing efficiency and measurement of the extent of oxygen-inhibited layer. In respect to mechanical properties, Vickers hardness and wear resistance using the toothbrush abrasion method and the OHSU oral wear simulator were evaluated. Surface roughness, color and gloss stability due to abrasion were also tested. Finally, biological evaluation included toxicity and estrogenicity testing. Analysis of molecular composition and measurement of the degree of conversion (DC%) in the irradiated specimens was performed using micro-attenuated total reflectance Fourier transform infrared spectroscopy (micro-ATR FTIR). Spectra acquisition was performed on an FTIR spectrometer equipped with a micro-ATR cell operated under the following conditions: 4000-600 cm-1 range, 4 cm-1 resolution, 20 scans coaddition, 2 mm diamond minicrystal of a single internal reflection, ZnSe lenses and 2 μm depth of analysis at 1000 cm-1. For chemical analysis, cylindrical specimens (Ø:8.0mm, h:1.5mm, n=5) were fabricated without being polymerized. The same specimens were used for the evaluation of DC% after being exposed for 20s to a halogen light-curing unit operated in standard irradiation mode at 750 mW/cm2 light intensity. In this case, an uncured specimen from each CSS tested was used as control material. The DC% of the tested surfaces was calculated by the two frequency technique using the net peak absorbance areas of C=C stretching vibrations at 1638 cm-1 as analytical frequency and the aromatic C···C stretching vibrations at 1605 cm-1 as reference frequency according to the equation: DC%= 100 X [1-AM (C···C) X AP (C=C) / AM (C=C) X AP (C···C)],where, AM and AP are the net peak absorbance height ratios of the uncured and cured materials, respectively. The peak absorbance height ratios were measured from the curve fitted spectra at the region 1675-1550 cm-1 following peak fitting with Peak-Fit software (v 4.12, SeaSolve Software Inc., Framingham, MA, USA) employing the Pearson IV amplitude curve fitting (standard width per spectrum), after baseline correction (2nd derivative zero algorithm).For measurement of the oxygen-inhibited layer, the standard film thickness method, employing 100-μm thick spacers was used. Briefly, a 10 μl drop of uncured CSS was placed on a microscopic glass slide, transferred on the stage of a light-transmission microscope (DM4000B, Leica Microsystems, Wetzlar, Germany) and covered with a glass slip with two similar slips used as spacers placed on each side. After wetting equilibrium occurred (~10 s), an uncured material disk was created with a diameter of ~8 mm and resin-air contact possible only at the disk periphery. Specimens (n=5) were light-cured as described previously. The thickness of the oxygen inhibited layer was measured at three different locations on each specimen, 5 min after irradiation, and averaged to obtain a single value that was reported for a given specimen.The specimens used for the degree of conversion measurements were further utilized sequentially to measure hardness 10 min after light-curing. Another series of specimens was prepared as described previously and tested following one week storage in H2O at 37οC. Measurements were made on the top and the bottom surfaces using a Vickers hardness tester (load 1 Kp, 10 s, 70Χ). To evaluate morphological changes on the surface of CSS products upon abrasion, resin composite specimens were constructed (8.0mm x 3.0mm x 2.0mm, n=4), which were covered with each product of CSS, embedded in an epoxy ring mold and placed in the toothbrush abrasion device (25000 cycles with toothpaste and H2O). Specimens’ surfaces were examined, before and after abrasion, under a stereomicroscope. Resin composite surface, polished with silicon carbide papers (300-1000 grit), was used as control surface. OHSU oral wear simulator was also used to evaluate the wear resistance of CSS. Specimens were fabricated, as previously described (8.0mm x 3.0mm x 2.0mm, n=4), using two of the CSS products (GC and PS), and mounted individually in a two part cold-setting acrylic resin to produce cylinders compatible with the chambers of the wear testing apparatus. Prior to wear testing the specimens were scanned using the non-contact optical profilometer. Each of the specimens was secured into an individual wear chamber of the wear simulator and food-like slurry was added to each chamber. The antagonist consisted of steatite spheres which were repeatedly driven along a 7 mm path at 20 N to simulate abrasion wear. At the end of the 7 mm path a 90 N force was applied to simulate attrition wear for 50,000 wear cycles at a frequency of 1 Hz (equivalent to 6 months wear in the oral environment). The tear drop wear facet produced on the surface of each specimen was analysed using optical profilometry. The total volumetric wear, surface roughness and maximum wear depth measurements were determined using the non-worn areas around the wear facet as a reference. The same specimens used in the toothbrush wear testing (8.0mm x 3.0mm x 2.0mm, n=4) were used for color measurements. Color measurements were performed, before and after abrasion with the toothbrush method, using a colorimeter. The CIE-L*a*b* color system was used to determine the color differences by the equation ΔΕ*= [(ΔL*)2+(Δa*)2+(Δb*)2]1/2, where ΔΕ* represents color change and ΔL*, Δa*, Δb* represent change of parameters L*, a*, b*, respectively. The same specimens (8.0mm x 3.0mm x 2.0mm, n=4) were also used for surface gloss assessment. Gloss was measured, before and after abrasion with toothbrush abrasion method, at 60o incidence angle with a calibrated infrared gloss-meter. For biological testing, cylindrical CSS specimens were fabricated (Ø:8.0mm, h:1.5mm, n=4), which were immersed in sterile glass tubes with 50 ml of normal saline (NS) at 37οC for 2 weeks. Then, specimens were removed from the glass tubes and two solutions were prepared (1% και 5% v/v). Toxicity and estrogenicity testing was performed based on standardized procedures. NS was used as control material. To evaluate statistically significant differences between mean values of DC%, extent of oxygen inhibited zone, color and gloss changes among materials tested, one-way analysis of variance (ANOVA) and Tukey’s multiple comparison test were used. Statistical analysis for Vickers hardness testing was done using three-way analysis of variance (ANOVA) and Tukey’s multiple comparison test. Statistical analysis for total volumetric wear, surface roughness and maximum wear depth upon abrasion was performed using t-test.Statistical analysis for biological testing was done using two-way analysis of variance (ANOVA) and Tukey’s multiple comparison test.Pearson correlation coefficient was used to identify correlations between DC%, VHN and cytotoxicity.Statistical analysis was performed using IBM SPSS Statistics 20 software at an α: 0.05 significance level. Results: - Chemical analysis showed that, in addition to the information given by the manufacturers, products BC, DF and GC contain aromatic monomers. In addition, GC showed the presence of N-H compounds. BC showed the greatest contribution of -OH s peak, followed by PS. - PS demonstrated highest conversion compared to BC, DF and GC.- Polymerization of products BC and GC resulted in lower extent of oxygen-inhibited zone, compared to PS and DF.- In respect to hardness testing, 10 minutes after polymerization, product GC presented higher values of Vickers hardness, followed by BC and DF, and finally, by PS, which presented the lower values of Vickers hardness. After storage in H2O, products BC and DF presented the higher values of Vickers hardness, followed by GC, while PS showed the lower values. For both storage conditions (10 minutes after polymerization and after 1 week storage in H2O) and for all products tested, there was no statistically significant difference in hardness values recorded for top and bottom surfaces. Storage in H2O resulted in significant decrease in hardness values for all products tested, in both top and bottom surfaces. However, the most significant decrease was recorded for products GC and PS. - Examination under a stereomicroscope revealed the best topography in BC and DF before, and in PS after toothbrush abrasion. Abrasion tracks were identified in GC and DF, whereas BC showed porosity.- Products PS and GC did not differ in total volumetric wear values, maximum attrition depth and mean depth of the entire wear facet upon abrasion. - GC resulted in rougher surface upon abrasion, compared to PS. - The only statistically significant difference was found in ΔL* values between GC and the rest materials, with the former being much brighter after toothbrush abrasion. The differences in hue (Δa*) and chroma (Δb*) coordinates revealed a red/yellow color shift for DF and a yellow color shift for GC following toothbrush abrasion. The ΔΕ* values ranged from 0.67 to 1.11. The most stable material regarding color changes was the PS. - All products resulted in significant gloss reduction after toothbrush wear. Although BC and PS before abrasion, had glossier surfaces compared to DF and GC, they presented the highest gloss reduction. After abrasion, gloss values of PS were still higher than those recorded for DF and GC.- Regarding toxicity testing, at 1% v/v eluent concentration, only DF showed statistically significant toxicity. However, at 5% v/v eluent concentration, all sealers demonstrated cytotoxicity. More specifically, at 5% v/v eluent concentration sealers BC και DF were the most toxic, while GC and PS revealed moderate toxicity. Toxicity at 5% v/v eluent concentration was more intense compared to1% v/v eluent concentration for all products tested. Finally, estrogenicity was not recorded for any of the sealers tested. Conclusions:- The qualitative material compositions given by the manufacturers do not correspond to the actual monomer composition of the products.- PS demonstrated highest conversion compared to BC, DF and GC.- BC and GC showed significantly lower extent of oxygen-inhibited layer compared to PS and DF. - In respect to hardness testing, 10 minutes after polymerization, product GC presented higher values of Vickers hardness, followed by BC, DF, and finally, by PS. After storage in water, products BC and DF presented the higher values of Vickers hardness, followed by GC, while PS showed the lower values. Storage in H2O resulted in significant decrease in hardness values for all products tested, in both top and bottom surfaces, indicating a strong plasticization effect. However, the most significant decrease was recorded for products GC and PS. - Examination under a stereomicroscope revealed the best topography in BC and DF before abrasion and in PS after toothbrush abrasion. - Optical profilometry showed significantly increased roughness values and similar material volume loss, mean and maximum wear depth upon abrasion, in GC compared to PS. - ΔΕ* values ranged from 0.67 to 1.11. The most stable material regarding color changes was the PS. - Prior to toothbrush wear testing, BC and PS revealed the glossiest surfaces among the materials tested. All products resulted in significant gloss reduction upon abrasion. BC and PS presented the highest gloss reduction. However, PS remained glossier than DF and GC after abrasion. - Products BC and DF revealed increased cytotoxicity compared to GC and PS, which demonstrated moderate toxicity. None of the products revealed estrogenicity. Significance: The results of the present study showed statistically significant differences in all material properties, among all the products tested. Therefore, the null hypothesis should be rejected. The great variations in the chemical, mechanical, surface and biological properties among the materials tested may influence their clinical performance. For accelerated wear testing, where only filled (GC) and unfilled (PS) materials were evaluated, the null hypothesis should be partially rejected, because no statistically significant difference was found in volume loss, maximum and mean wear depth.

Σκοπός: Η συστηματική αξιολόγηση της εργαστηριακής συμπεριφοράς μιας σειράς αντιπροσωπευτικών σκευασμάτων CSS ως προς τις μηχανικές, χημικές, επιφανειακές και βιολογικές τους ιδιότητες. Η υπόθεση εργασίας ήταν ότι δεν υπάρχει στατιστικά σημαντική διαφορά στις επιμέρους ιδιότητες μεταξύ των αντιπροσωπευτικών σκευασμάτων CSS που χρησιμοποιήθηκαν στην εργασία. Επιλέχθησαν αντιπροσωπευτικά, ως προς τη χημική σύνθεση, σκευάσματα CSS. Τα υπό μελέτη υλικά ήταν τα εξής: Biscover LV (BC) (Bisco, Inc., Schaumburg, IL, USA), DuraFinish (DF) (Parkell, Inc., Edgewood, NY, USA), G-Coat Plus (GC) (GC Corporation, Tokyo, Japan) και PermaSeal (PS) (Ultradent Products, Inc., S. Jordan, UT, USA). Υλικά και μέθοδος: Από τις χημικές ιδιότητες, ελέγχθηκε η μοριακή σύνθεση και υπολογίστηκε ο βαθμός μετατροπής των δεσμών C=C και η έκταση της ζώνης αναστολής του πολυμερισμού από το ατμοσφαιρικό οξυγόνο. Όσον αφορά στις μηχανικές ιδιότητες, υπολογίστηκε η σκληρότητα κατά Vickers (VHN) και η αποτριβή (με τη μέθοδο της οδοντόβουρτσας και με τη μέθοδο φόρτισης με στυλεό). Από τις επιφανειακές ιδιότητες, μετρήθηκε η επιφανειακή τραχύτητα, η χρωματική σταθερότητα και η μεταβολή της στιλπνότητας μετά από αποτριβή. Ο βιολογικός έλεγχος περιελάμβανε τον έλεγχο της τοξικότητας και της οιστρογονομιμητικής δράσης των CSS. Η στατιστική ανάλυση των αποτελεσμάτων για τις επιμέρους παραμέτρους πραγματοποιήθηκε με τη μέθοδο διακύμανσης (analysis of variance-ANOVA) και με τη μέθοδο t-test (α:0,05). Η πιθανή συσχέτιση της κυτταροτοξικότητας με τα DC%, VHN ελέγχθηκε με τη δοκιμασία Pearson correlation coefficient.Aποτελέσματα:Χημικές ιδιότητεςΤα σκευάσματα BC, DF και GC περιέχουν, πρόσθετα από τα στοιχεία που δίνουν οι κατασκευάστριες εταιρείες, αρωματικές ουσίες. Επιπλέον, στο GC παρουσιάστηκαν ομάδες N-H, ενώ το BC εμφάνισε τη μεγαλύτερη κορυφή OH, ακολουθούμενο από το PS. Το σκεύασμα PS παρουσίασε υψηλότερο βαθμό μετατροπής δεσμών C=C συγκρινόμενο με τα BC, DF και GC. Τα BC και GC παρουσίασαν μικρότερη σε έκταση ζώνης αναστολής πολυμερισμού από το οξυγόνο, συγκρινόμενα με τα PS και DF. Μηχανικές ιδιότητεςΠριν την αποθήκευση σε νερό, το GC παρουσίασε τις πιο υψηλές τιμές σκληρότητας. Ακολούθησαν τα BC και DF, τα οποία δεν διέφεραν μεταξύ τους, και τέλος, το PS. Μετά την αποθήκευση σε νερό, τις πιο υψηλές τιμές σκληρότητας παρουσίασαν τα BC και DF. Ακολούθησε το GC, ενώ το PS εξακολούθησε να έχει τις πιο χαμηλές τιμές σκληρότητας. Δεν παρατηρήθηκε διαφορά στις τιμές της σκληρότητας μεταξύ επιφάνειας και βάσης των δοκιμίων. Η παραμονή στο νερό οδήγησε σε μείωση της σκληρότητας (κυρίως στα GC και PS). Η επιφανειακή μορφολογία των υπό μελέτη υλικών μετά την αποτριβή παρουσίασε διαφορές. Ανεξάρτητα από το είδος των μορφολογικών χαρακτηριστικών της επιφάνειάς τους, τα BC και DF παρουσίασαν πιο λεία επιφάνεια συγκρινόμενα με τα PS και GC πριν την αποτριβή, ενώ το PS μετά την αποτριβή. Τα PS και GC δεν παρουσίασαν διαφορά στις τιμές της απώλειας όγκου λόγω αποτριβής και στο μέγιστο και μέσο βάθος αποτριβής. Επιφανειακές ιδιότητεςΤo GC παρουσίασε πιο αδρή επιφάνεια μετά την αποτριβή σε σχέση με το PS. Παρατηρήθηκε στατιστικά σημαντική διαφορά στις τιμές ΔL* μεταξύ του GC και των υπόλοιπων υλικών (p<0.001), το οποίο μετά την αποτριβή με την οδοντόβουρτσα ήταν πιο φωτεινό. Οι διαφορές στις παραμέτρους Δa* και Δb* έδειξαν μετατόπιση του χρώματος προς το κόκκινο για το υλικό DF και προς το κίτρινο για το υλικό GC μετά την αποτριβή. Οι τιμές ΔΕ* κυμάνθηκαν μεταξύ 0.67 και 1.11. Το υλικό PS παρουσίασε τη μεγαλύτερη χρωματική σταθερότητα. Οι μεταβολές αυτές, ωστόσο, ήταν μικρότερες από το όριο του κλινικά αντιληπτού (ΔΕ*<3.3). Τα BC και PS, πριν την αποτριβή, παρουσίασαν πιο στιλπνή επιφάνεια και μεγαλύτερη μείωση της στιλπνότητας μετά την αποτριβή, συγκρινόμενα με τα DF και GC. Το υλικό PS παρέμεινε πιο στιλπνό μετά την αποτριβή, σε σχέση με τα DF και GC.Βιολογικές ιδιότητεςΣτην ομάδα με τα διαλύματα συγκέντρωσης 1% v/v, μόνο το DF παρουσίασε τοξικότητα. Στην ομάδα 5% v/v, όλα τα υλικά παρουσίασαν τοξικότητα (τα BC και DF ήταν πιο τοξικά). Η τοξικότητα στην ομάδα διαλυμάτων συγκέντρωσης 5% v/v ήταν μεγαλύτερη για όλα τα υλικά. Η μόνη στατιστικά σημαντική συσχέτιση που βρέθηκε ήταν μεταξύ DC% και κυτταροτοξικότητας 5% v/v Κανένα υλικό δεν παρουσίασε οιστρογονομιμητική δράση. ΣυμπεράσματαΣύμφωνα με τα αποτελέσματα της εργασίας, η άκυρη υπόθεση ότι δεν υπάρχει στατιστικά σημαντική διαφορά στις επιμέρους ιδιότητες μεταξύ των αντιπροσωπευτικών σκευασμάτων CSS, απορρίφθηκε. Τα υπό μελέτη υλικά παρουσίασαν μεταξύ τους διαφορές ως προς τις χημικές, μηχανικές, επιφανειακές και βιολογικές ιδιότητες, οι οποίες μπορούν να επηρεάσουν την κλινική τους συμπεριφορά. Για τη δοκιμασία αποτριβής με τη μέθοδο OHSU, όπου τα υλικά δεν παρουσίασαν διαφορά στην απώλεια όγκου και στο μέγιστο και μέσο βάθος αποτριβής αλλά στις τιμές της τραχύτητας μετά την αποτριβή, η υπόθεση εργασίας έγινε εν μέρει δεκτή.

SUMMARY In vitro evaluation of composite surface sealers Μaria Anagnostou , DDS, MS, DrMedPhD Candidate, Department of Operative Dentistry, University of Athens, School of DentistryObjectives: The aim of the present study was to evaluate the chemical, mechanical, surface and biological properties of composite surface sealers (CSS) with different monomer composition. The null hypothesis was that no statistically significant differences exist among the CSS in the properties tested.Representative, regarding molecular composition, products of CSS were chosen. Products tested were Biscover LV (BC) (Bisco, Inc., Schaumburg, IL, USA), DuraFinish (DF) (Parkell, Inc., Edgewood, NY, USA), G-Coat Plus (GC) (GC Corporation, Tokyo, Japan) and PermaSeal (PS) (Ultradent Products, Inc., S. Jordan, UT, USA). Materials and methods: In vitro evaluation included analysis of chemical composition of monomers contained in CSS products, evaluation of curing efficiency and measurement of the extent of oxygen-inhibited layer. In respect to mechanical properties, Vickers hardness and wear resistance using the toothbrush abrasion method and the OHSU oral wear simulator were evaluated. Surface roughness, color and gloss stability due to abrasion were also tested. Finally, biological evaluation included toxicity and estrogenicity testing. Analysis of molecular composition and measurement of the degree of conversion (DC%) in the irradiated specimens was performed using micro-attenuated total reflectance Fourier transform infrared spectroscopy (micro-ATR FTIR). Spectra acquisition was performed on an FTIR spectrometer equipped with a micro-ATR cell operated under the following conditions: 4000-600 cm-1 range, 4 cm-1 resolution, 20 scans coaddition, 2 mm diamond minicrystal of a single internal reflection, ZnSe lenses and 2 μm depth of analysis at 1000 cm-1. For chemical analysis, cylindrical specimens (Ø:8.0mm, h:1.5mm, n=5) were fabricated without being polymerized. The same specimens were used for the evaluation of DC% after being exposed for 20s to a halogen light-curing unit operated in standard irradiation mode at 750 mW/cm2 light intensity. In this case, an uncured specimen from each CSS tested was used as control material. The DC% of the tested surfaces was calculated by the two frequency technique using the net peak absorbance areas of C=C stretching vibrations at 1638 cm-1 as analytical frequency and the aromatic C···C stretching vibrations at 1605 cm-1 as reference frequency according to the equation: DC%= 100 X [1-AM (C···C) X AP (C=C) / AM (C=C) X AP (C···C)],where, AM and AP are the net peak absorbance height ratios of the uncured and cured materials, respectively. The peak absorbance height ratios were measured from the curve fitted spectra at the region 1675-1550 cm-1 following peak fitting with Peak-Fit software (v 4.12, SeaSolve Software Inc., Framingham, MA, USA) employing the Pearson IV amplitude curve fitting (standard width per spectrum), after baseline correction (2nd derivative zero algorithm).For measurement of the oxygen-inhibited layer, the standard film thickness method, employing 100-μm thick spacers was used. Briefly, a 10 μl drop of uncured CSS was placed on a microscopic glass slide, transferred on the stage of a light-transmission microscope (DM4000B, Leica Microsystems, Wetzlar, Germany) and covered with a glass slip with two similar slips used as spacers placed on each side. After wetting equilibrium occurred (~10 s), an uncured material disk was created with a diameter of ~8 mm and resin-air contact possible only at the disk periphery. Specimens (n=5) were light-cured as described previously. The thickness of the oxygen inhibited layer was measured at three different locations on each specimen, 5 min after irradiation, and averaged to obtain a single value that was reported for a given specimen.The specimens used for the degree of conversion measurements were further utilized sequentially to measure hardness 10 min after light-curing. Another series of specimens was prepared as described previously and tested following one week storage in H2O at 37οC. Measurements were made on the top and the bottom surfaces using a Vickers hardness tester (load 1 Kp, 10 s, 70Χ). To evaluate morphological changes on the surface of CSS products upon abrasion, resin composite specimens were constructed (8.0mm x 3.0mm x 2.0mm, n=4), which were covered with each product of CSS, embedded in an epoxy ring mold and placed in the toothbrush abrasion device (25000 cycles with toothpaste and H2O). Specimens’ surfaces were examined, before and after abrasion, under a stereomicroscope. Resin composite surface, polished with silicon carbide papers (300-1000 grit), was used as control surface. OHSU oral wear simulator was also used to evaluate the wear resistance of CSS. Specimens were fabricated, as previously described (8.0mm x 3.0mm x 2.0mm, n=4), using two of the CSS products (GC and PS), and mounted individually in a two part cold-setting acrylic resin to produce cylinders compatible with the chambers of the wear testing apparatus. Prior to wear testing the specimens were scanned using the non-contact optical profilometer. Each of the specimens was secured into an individual wear chamber of the wear simulator and food-like slurry was added to each chamber. The antagonist consisted of steatite spheres which were repeatedly driven along a 7 mm path at 20 N to simulate abrasion wear. At the end of the 7 mm path a 90 N force was applied to simulate attrition wear for 50,000 wear cycles at a frequency of 1 Hz (equivalent to 6 months wear in the oral environment). The tear drop wear facet produced on the surface of each specimen was analysed using optical profilometry. The total volumetric wear, surface roughness and maximum wear depth measurements were determined using the non-worn areas around the wear facet as a reference. The same specimens used in the toothbrush wear testing (8.0mm x 3.0mm x 2.0mm, n=4) were used for color measurements. Color measurements were performed, before and after abrasion with the toothbrush method, using a colorimeter. The CIE-L*a*b* color system was used to determine the color differences by the equation ΔΕ*= [(ΔL*)2+(Δa*)2+(Δb*)2]1/2, where ΔΕ* represents color change and ΔL*, Δa*, Δb* represent change of parameters L*, a*, b*, respectively. The same specimens (8.0mm x 3.0mm x 2.0mm, n=4) were also used for surface gloss assessment. Gloss was measured, before and after abrasion with toothbrush abrasion method, at 60o incidence angle with a calibrated infrared gloss-meter. For biological testing, cylindrical CSS specimens were fabricated (Ø:8.0mm, h:1.5mm, n=4), which were immersed in sterile glass tubes with 50 ml of normal saline (NS) at 37οC for 2 weeks. Then, specimens were removed from the glass tubes and two solutions were prepared (1% και 5% v/v). Toxicity and estrogenicity testing was performed based on standardized procedures. NS was used as control material. To evaluate statistically significant differences between mean values of DC%, extent of oxygen inhibited zone, color and gloss changes among materials tested, one-way analysis of variance (ANOVA) and Tukey’s multiple comparison test were used. Statistical analysis for Vickers hardness testing was done using three-way analysis of variance (ANOVA) and Tukey’s multiple comparison test. Statistical analysis for total volumetric wear, surface roughness and maximum wear depth upon abrasion was performed using t-test.Statistical analysis for biological testing was done using two-way analysis of variance (ANOVA) and Tukey’s multiple comparison test.Pearson correlation coefficient was used to identify correlations between DC%, VHN and cytotoxicity.Statistical analysis was performed using IBM SPSS Statistics 20 software at an α: 0.05 significance level. Results: - Chemical analysis showed that, in addition to the information given by the manufacturers, products BC, DF and GC contain aromatic monomers. In addition, GC showed the presence of N-H compounds. BC showed the greatest contribution of -OH s peak, followed by PS. - PS demonstrated highest conversion compared to BC, DF and GC.- Polymerization of products BC and GC resulted in lower extent of oxygen-inhibited zone, compared to PS and DF.- In respect to hardness testing, 10 minutes after polymerization, product GC presented higher values of Vickers hardness, followed by BC and DF, and finally, by PS, which presented the lower values of Vickers hardness. After storage in H2O, products BC and DF presented the higher values of Vickers hardness, followed by GC, while PS showed the lower values. For both storage conditions (10 minutes after polymerization and after 1 week storage in H2O) and for all products tested, there was no statistically significant difference in hardness values recorded for top and bottom surfaces. Storage in H2O resulted in significant decrease in hardness values for all products tested, in both top and bottom surfaces. However, the most significant decrease was recorded for products GC and PS. - Examination under a stereomicroscope revealed the best topography in BC and DF before, and in PS after toothbrush abrasion. Abrasion tracks were identified in GC and DF, whereas BC showed porosity.- Products PS and GC did not differ in total volumetric wear values, maximum attrition depth and mean depth of the entire wear facet upon abrasion. - GC resulted in rougher surface upon abrasion, compared to PS. - The only statistically significant difference was found in ΔL* values between GC and the rest materials, with the former being much brighter after toothbrush abrasion. The differences in hue (Δa*) and chroma (Δb*) coordinates revealed a red/yellow color shift for DF and a yellow color shift for GC following toothbrush abrasion. The ΔΕ* values ranged from 0.67 to 1.11. The most stable material regarding color changes was the PS. - All products resulted in significant gloss reduction after toothbrush wear. Although BC and PS before abrasion, had glossier surfaces compared to DF and GC, they presented the highest gloss reduction. After abrasion, gloss values of PS were still higher than those recorded for DF and GC.- Regarding toxicity testing, at 1% v/v eluent concentration, only DF showed statistically significant toxicity. However, at 5% v/v eluent concentration, all sealers demonstrated cytotoxicity. More specifically, at 5% v/v eluent concentration sealers BC και DF were the most toxic, while GC and PS revealed moderate toxicity. Toxicity at 5% v/v eluent concentration was more intense compared to1% v/v eluent concentration for all products tested. Finally, estrogenicity was not recorded for any of the sealers tested. Conclusions:- The qualitative material compositions given by the manufacturers do not correspond to the actual monomer composition of the products.- PS demonstrated highest conversion compared to BC, DF and GC.- BC and GC showed significantly lower extent of oxygen-inhibited layer compared to PS and DF. - In respect to hardness testing, 10 minutes after polymerization, product GC presented higher values of Vickers hardness, followed by BC, DF, and finally, by PS. After storage in water, products BC and DF presented the higher values of Vickers hardness, followed by GC, while PS showed the lower values. Storage in H2O resulted in significant decrease in hardness values for all products tested, in both top and bottom surfaces, indicating a strong plasticization effect. However, the most significant decrease was recorded for products GC and PS. - Examination under a stereomicroscope revealed the best topography in BC and DF before abrasion and in PS after toothbrush abrasion. - Optical profilometry showed significantly increased roughness values and similar material volume loss, mean and maximum wear depth upon abrasion, in GC compared to PS. - ΔΕ* values ranged from 0.67 to 1.11. The most stable material regarding color changes was the PS. - Prior to toothbrush wear testing, BC and PS revealed the glossiest surfaces among the materials tested. All products resulted in significant gloss reduction upon abrasion. BC and PS presented the highest gloss reduction. However, PS remained glossier than DF and GC after abrasion. - Products BC and DF revealed increased cytotoxicity compared to GC and PS, which demonstrated moderate toxicity. None of the products revealed estrogenicity. Significance: The results of the present study showed statistically significant differences in all material properties, among all the products tested. Therefore, the null hypothesis should be rejected. The great variations in the chemical, mechanical, surface and biological properties among the materials tested may influence their clinical performance. For accelerated wear testing, where only filled (GC) and unfilled (PS) materials were evaluated, the null hypothesis should be partially rejected, because no statistically significant difference was found in volume loss, maximum and mean wear depth.