Antibacterial activity, cytocompatibility and effect of Bio-C Temp bioceramic intracanal medicament on osteoblast biology.

AIM: To analyse the antimicrobial and biological properties of a new bioceramic intracanal medicament (Bio-C Temp), and to compare it with two calcium hydroxide-based intracanal medicaments (Calen® and UltraCal® XS). METHODOLOGY: The direct contact and the crystal violet tests were performed to assess the antimicrobial activity of intracanal medicaments against Enterococcus faecalis. The cytocompatibility and the effect of the medication on the biology of the human osteoblast-like cell line (Saos-2) were evaluated with methylthiazole tetrazolium (MTT), neutral red, alkaline phosphatase activity and mineralization (alizarin red) assays. The data were analysed using one-way anova and Tukey's tests, two-way anova and Bonferroni's tests, or Kruskal-Wallis and Dunn's tests (α = 0.05). RESULTS: Bio-C Temp had significantly less antibacterial activity and biofilm biomass reduction than the other intracanal medicaments (P < 0.05). There was no difference in the viability of Saos-2 exposed to the various intracanal medicaments, except regarding the 1 : 2 dilution, when the Bio-C Temp group had significantly lower cell viability than the UltraCal® XS and Calen® groups (P < 0.05). Bio-C Temp induced significantly greater ALP activity than the other intracanal medicaments (P < 0.05) at day 1. Calen® induced significantly greater deposition of mineralized nodules than the other intracanal medicaments (P < 0.05), and no difference was observed between Bio-C Temp and UltraCal® XS (P > 0.05). CONCLUSIONS: Bio-C Temp had similar cytocompatibility at higher dilutions, and higher or similar induction of ALP activity and deposition of mineralized nodules in comparison with Calen® and UltraCal® XS. However, it had significantly less antibacterial and antibiofilm activity than Calen® and UltraCal® XS.

Evaluation of the biological properties of two experimental calcium silicate sealers: an in vivo study in rats.

AIM: To evaluate the biological properties of experimental sealers based on tricalcium silicate and dicalcium silicate, manipulated with polyethylene glycol (CE-1) and with the addition of calcium hypochlorite (CE-2) compared to AH Plus (AHP) and TotalFill BC Sealer (TBC). METHODOLOGY: The tissue reaction caused by the materials in the subcutaneous tissue of rats was evaluated after implantation of polyethylene tubes filled with the materials at 7, 15, 30 and 60 days. Sections were stained with haematoxylin and eosin (HE) for morphological analysis and to evaluated number of inflammatory cells/mm2 (ICs). Sections were used for immunohistochemical detection of interleukin-6 (IL-6) and osteocalcin (OC). The von Kossa method was used to identify calcium precipitation in the capsules. The data were submitted to anova and Tukey's tests, with 5% significance level. RESULTS: At 7 days, CE-1, CE-2 and AHP had higher numbers of ICs. AHP presented higher immunolabelling for IL-6. After 15 days, regarding IL-6, there was no difference between CE-2 and the control group. At 30 days, AHP exhibited the highest number of IC (P < 0.05) and CE-2 and the control group presented the lowest ICs and IL-6-positive cells. After 60 days, all materials exhibited decreases in ICs. CE-2, TBC and the control had the lowest values (P < 0.05). No significant difference was detected between CE-1 and TBC, and between CE-2 and control considering the immunoexpression of IL-6. In this period, AHP had the greatest number of IC and IL-6 (P < 0.05). In all periods, CE-1, CE-2 and TBC sealers had von Kossa-positive structures and OC-immunolabelled cells. CE-2 had higher number of OC-positive cells than the CE-1 and TBC sealers (P < 0.05), in all periods. OC immunolabelling was not observed in the capsules of AH Plus and the control groups. CONCLUSIONS: The experimental sealer and its association with calcium hypochlorite, in addition to TotalFill BC Sealer, were biocompatible and had bioactive potential.

Histomorphometric and immunohistochemical study shows that tricalcium silicate cement associated with zirconium oxide or niobium oxide is a promising material in the periodontal tissue repair of rat molars with perforated pulp chamber floors.

AIM: To evaluate the periodontium response to tricalcium silicate (TCS) with zirconium oxide (ZrO2 ) or niobium oxide (Nb2 O5 ) used in the sealing of perforated pulp chamber floors in rat maxillary molars. METHODOLOGY: In eighty rats, the perforations in right maxillary molars were filled with either TCS + ZrO2 , TCS + Nb2 O5 , White MTA (used as a gold standard material) or no repair material was placed (Sham Group, SG); the left molars of SG, were used as controls (CG). Sections of maxillary fragments following 7, 15, 30 and 60 days were used to evaluate the volume densities of inflammatory cells (VvIC) and fibroblasts (VvFb), width of the periodontal space, amount of collagen, number of osteoclasts and number of IL-6-immunostained cells. The data were subjected to two-way ANOVA followed by Tukey's test (P ≤ 0.05). RESULTS: At all periods, significant differences in VvIC were not detected among TCS + ZrO2, TCS + Nb2 O5 and MTA groups, which had values significantly lower (P < 0.05) than the SG. Significant differences in the number of IL-6-immunolabelled cells were not observed among TCS + ZrO2 , TCS + Nb2 O5 and MTA groups (P > 0.05) at 15, 30 and 60 days. At 7, 15 and 30 days, the number of osteoclast was significantly greater in TCS + ZrO2, TCS + Nb2 O5 and MTA (P < 0.05) than in the CG; no significant difference was detected after 60 days (P > 0.05). The width of the periodontal space and amount of collagen in TCS + ZrO2 and TCS + Nb2 O5 groups were similar to the CG at 30 and 60 days while SG specimens had a significant reduction (P < 0.05) in the amount of collagen and significant increase (P < 0.05) in the width of the periodontal space. CONCLUSIONS: TCS + ZrO2 and TCS + Nb2 O5 were associated with periodontium repair since these materials allowed the reestablishment of periodontal space width and collagen formation when used in the filling of uninfected perforations in the pulp chamber floor of maxillary rat molars. Furthermore, the significant reduction in the periodontal space of TCS + ZrO2 and TCS + Nb2 O5 specimens after 60 days confirmed that the experimental materials were associated with a more rapid recovery of the injured tissues than MTA.

Sugarcane cystatin CaneCPI-1 promotes osteogenic differentiation in human dental pulp cells: a new insight into cysteine proteases inhibitors.

AIM: To investigate the biocompatibility, type of cell death, osteogenic bioactivity and mRNA expression of the osteogenic markers, induced by CaneCPI-1 in human dental pulp cells (hDPCs). METHODOLOGY: hDPCs exposed to CaneCPI-1 and not exposed (control) were evaluated for cell viability by the 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide (MTT) assay; apoptosis by flow cytometry; alkaline phosphatase (ALP) activity by calculation of thymolphthalein release; gene expression of bone morphogenetic protein 2 (BMP-2), runt-related transcription factor 2 (RUNX2), ALP, osteocalcin (OC), bone sialoprotein (BSP) by qPCR; and mineralized nodules production by using alizarin red staining. The data were analysed by one-way analysis of variance (anova) and Turkey's post-test, two-way anova and Bonferroni post-test or t-test (P < 0.05). RESULTS: CaneCPI-1 induced no apoptosis and had no cytotoxic effect, except in the concentration of 33.20 µm, in which cell viability was significantly lower than the control (α-MEM nonosteogenic medium serum-free) (P < 0.05). There was significantly greater ALP activity, greater expression of the BMP-2, RUNX2, ALP, OC and BSP genes and greater mineralized nodules production in the CaneCPI-1 group in comparison with the control or osteogenic α-MEM control (α-MEM osteogenic medium - L-ascorbic acid and ß-glycerophosphate) (P < 0.05). CONCLUSIONS: CaneCPI-1 was cytocompatible and also induced the differentiation of hDPCs in osteogenic phenotype in vitro. CaneCPI-1 is a promising molecule to induce pulp repair.

Effects of octenidine applied alone or mixed with sodium hypochlorite on eukaryotic cells.

AIM: To assess the effects of octenidine dihydrochloride (OCT) on eukaryotic cells and the cytotoxicity of OCT associated with sodium hypochlorite - NaOCl (NaOCl/OCT). METHODOLOGY: L929 fibroblasts and human osteoblast-like cells (Saos-2) were exposed to 0.1% OCT, 2% CHX, 2.5% NaOCl, 5.25% NaOCl and mixtures of 5.25% NaOCl and 0.1% OCT (NaOCl/OCT) at 90 : 10, 80 : 20 and 50 : 50 ratios. Cell viability was assessed by methyl-thiazol-tetrazolium (MTT) and neutral red (NR) assays; type of cell death, by flow cytometry; cytoskeleton, by actin and α-tubulin fluorescence; and alkaline phosphatase (ALP) activity, by thymolphthalein release. The data were analysed by two-way ANOVA and Bonferroni tests (α = 0.05). RESULTS: MTT and NR assays revealed that 0.1% OCT had the lowest cytotoxicity (P < 0.05), followed by 2% CHX (P < 0.05). The 2.5% NaOCl, NaOCl/OCT 80 : 20 and NaOCl/OCT 50 : 50 solutions had intermediate cytotoxicity. NaOCl 5.25% and NaOCl/OCT 90 : 10 had the highest cytotoxicity (P < 0.05). The OCT group had a higher percentage of viable cells than the NaOCl and CHX groups (P < 0.05), and induced apoptosis at higher doses. The cytoskeleton alterations were observed at 0.12%, 0.6% and 2.02% for the NaOCl, CHX and OCT groups, respectively. The solutions did not induce ALP activity. CONCLUSION: Octenidine dihydrochloride was less cytotoxic, induced apoptosis at higher doses, caused few changes in the cytoskeleton and did not induce alkaline phosphatase activity. In addition, octenidine dihydrochloride reduced the cytotoxicity of 5.25% NaOCl when combined at 20 and 50%.

Effect of immersion in distilled water or phosphate-buffered saline on the solubility, volumetric change and presence of voids within new calcium silicate-based root canal sealers.

AIM: To assess the effect of immersion in distilled water or phosphate-buffered saline (PBS) on the solubility, volumetric change and presence of voids of calcium silicate-based root canal sealers (TotalFill BC, Sealer Plus BC and Bio-C), in comparison with the gold standard epoxy resin-based sealer (AH Plus). METHODOLOGY: All properties were evaluated after immersion in distilled water or PBS. Solubility was determined by the percentage of mass loss, whereas volumetric change and presence of voids were evaluated by micro-computed tomography, after 7 days of immersion. The volumetric change and percentage of voids between the baseline (after setting) and the experimental period were calculated. Statistical analysis was performed using one-way anova and Tukey's or Student's t-tests (α = 0.05). RESULTS: The calcium silicate-based sealers had significantly greater solubility and volumetric loss than AH Plus, after immersion in distilled water or PBS (P < 0.05). Bio-C had the greatest solubility (P < 0.05), followed by TotalFill BC and Sealer Plus BC, which were similar (P > 0.05). Regarding the volumetric change, AH Plus had a volume increase, with similar values in distilled water and PBS (P > 0.05). TotalFill BC, Sealer Plus BC and Bio-C had a similar volumetric change (P > 0.05). The calcium silicate-based materials had the greatest solubility and volume loss after immersion in distilled water (P < 0.05). There was no difference in the percentage of voids amongst the sealers, before and after immersion in distilled water or PBS (P > 0.05). CONCLUSIONS: TotalFill BC, Sealer Plus BC and Bio-C had significantly greater solubility and volumetric loss than AH Plus. Although storage in PBS significantly reduced the solubility and volumetric change of calcium silicate-based sealers, their solubility remained above that recommend by ISO 6876. All the sealers evaluated had low and similar voids, even after immersion in distilled water or PBS.

Cytocompatibility, bioactive potential and antimicrobial activity of an experimental calcium silicate-based endodontic sealer.

AIM: To evaluate the cytocompatibility, bioactive potential, antimicrobial and antibiofilm activities of an experimental calcium silicate-based endodontic sealer, in comparison with TotalFill BC Sealer and AH Plus. METHODOLOGY: Cytocompatibility was assessed by methyltetrazolium (MTT) and neutral red (NR) assays, after exposure of the Saos-2 cells to the sealer extracts (1 : 2, 1 : 4, 1 : 8, 1 : 16 and 1 : 32 dilutions) for 24 h. The sealers were manipulated and placed in 12-well culture plates and exposed to ultraviolet light; then, 5 mL of DMEM without serum was added. Cell bioactivity was evaluated by alkaline phosphatase activity (ALP) and Alizarin red staining (ARS). Antimicrobial and antibiofilm activities were evaluated by direct contact test (DCT) on planktonic cells (DCTPC) and modified DCT on biofilm formed in bovine dentine blocks (MDCT). MTT, NR and ALP data were analysed by two-way anova and Bonferroni tests; ARS data by anova and Tukey's tests; and the microbiological data by Kruskal-Wallis and Dunn tests (α = 0.05). RESULTS: The experimental sealer, TotalFill BC and AH Plus were not cytotoxic to Saos-2, in comparison with the negative control (P > 0.05). Greater ALP was observed after 7 days of exposure of Saos-2 to AH Plus and the experimental sealer (P < 0.05) when compared to the control. Significantly greater mineralized nodule production was observed for TotalFill BC and the experimental sealer (P < 0.05). In DCTPC, the experimental sealer and TotalFill BC were associated with a significantly greater reduction of E. faecalis (P < 0.05) and eliminated C. albicans. In MDCT, the experimental sealer and TotalFill BC had significantly greater antibiofilm efficacy (P < 0.05). CONCLUSIONS: The experimental calcium silicate-based sealer was cytocompatible, bioactive, antimicrobial against E. faecalis and C. albicans and effective against E. faecalis biofilms, with potential for use in root canal treatment.

Biocompatibility of mineral trioxide aggregate flow and biodentine.

AIM: To evaluate the influence of powder-to-gel ratio (0.19 g powder to 50 µL of gel, thick MTA Flow, and 0.06 g powder to 50 µL of gel, fluid MTA Flow) on biocompatibility of MTA Flow (Ultradent Products Inc., South Jordan, UT, USA, lot: 2015122901) and compare it with Biodentine (Septodont Inc., Saint-Maur-des-Fossés, France, lot: B18542A). METHODOLOGY: The materials were manipulated and inserted into polyethylene tubes for implantation in twenty rats. After 7, 15, 30 and 60 days, the specimens were removed and embedded in paraffin. Haematoxylin and eosin sections were used to count the number of inflammatory cells (IC) and fibroblasts mm-2 (Fb). In the Masson's trichrome-stained sections, the fibrous capsule thickness was measured; picrosirius red-stained sections were used for birefringent collagen quantification. The data were submitted to two-way ANOVA and Tukey test (P ≤ 0.05). RESULTS: A significantly lower number of IC and consequently higher number of Fb were observed in the capsules adjacent to thick MTA Flow at all periods, in comparison with other materials (P ≤ 0.05). At 60 days, the quantity of birefringent collagen was significantly greater in the tissue in contact with thick MTA Flow, when compared with fluid MTA Flow and Biodentine. CONCLUSIONS: Although thick MTA Flow induced a less intense inflammatory response, all evaluated materials are biocompatible because they allowed regression of this process after 60 days.

Mast cells and immunoexpression of FGF-1 and Ki-67 in rat subcutaneous tissue following the implantation of Biodentine and MTA Angelus.

AIM: To compare the formation of fibrous capsules around Biodentine and MTA Angelus implants as well as the participation of fibroblast growth factor-1 (FGF-1) and mast cells in the tissue response to these endodontic materials. METHODOLOGY: Sixty polyethylene tubes filled with Biodentine or MTA, and empty tubes (control group) were implanted into the dorsal subcutaneous tissues of male rats. After 7, 15, 30 and 60 days, the specimens were embedded in paraffin and the number of fibroblasts and mast cells was quantified in the sections stained with Masson's trichrome or Alcian Blue, respectively. FGF-1 and Ki-67 were detected by immunohistochemistry, and the number of immunolabelled cells was computed. The collagen content was estimated in the picrosirius red-stained sections. The data were subjected to two-way ANOVA followed by Tukey's test (P ≤ 0.05). RESULTS: The capsules were associated with a significant increase (P < 0.0001) in the number of fibroblasts and mast cells, and in the collagen content over time. A significant decrease (P < 0.0001) in the immunoexpression of FGF-1 and Ki-67 was observed in all groups from the 7th-60th day. At 60 days, the number of fibroblasts (P = 0.0226) and the collagen content (P < 0.0001) were significantly greater in MTA than Biodentine specimens, while the greatest number of mast cells and FGF-1-immunolabelled cells was observed in Biodentine specimens (P < 0.0001). A significant difference in Ki-67 immunoexpression was not detected between specimens of Biodentine and MTA. CONCLUSIONS: The collagen-rich capsule formed slowly around Biodentine in comparison with MTA. FGF-1 and mast cells participated in capsule remodelling, stimulating fibroblast proliferation and subsequent collagen production, in response to subcutaneous implants.

Heparin is biocompatible and can induce differentiation of human dental pulp cells.

AIM: To investigate the biocompatibility, osteogenic bioactivity and mRNA expression of the osteo/odontogenic markers bone morphogenetic protein 2 (BMP-2), osteocalcin (OC) and alkaline phosphatase (ALP), induced by heparin in human dental pulp cells (hDPCs). METHODOLOGY: hDPCs were exposed to the heparin, and cell viability was assessed by 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide (MTT), and cell death was evaluated by flow cytometry. Osteogenic bioactivity was evaluated by the alkaline phosphatase (ALP) assay, and the detection of calcium deposits by alizarin red staining (ARS). The gene expression of BMP-2, OC and ALP was quantified with real-time PCR. Statistical analysis was performed with ANOVA and Bonferroni or Tukey post-test and t-test (α = 0.05). RESULTS: Heparin had no cytotoxic effect and did not induce apoptosis. After 3 days, heparin had significantly higher ALP activity in comparison with the control (P < 0.05). Heparin had a significant (P < 0.05) stimulatory effect on the formation of mineralized nodules. BMP-2 and OC mRNA expressions were significantly higher in cells exposed to heparin than control group after 1 day (P < 0.05). CONCLUSIONS: Heparin was biocompatible in hDPCs, induced osteogenic bioactivity and enhanced mRNA expression of osteo/odontogenic markers BMP-2 and OC. These results suggest that heparin has potential to induce osteo/odontogenic cell differentiation of hDPCs.

Counterclockwise or clockwise reciprocating motion for oval root canal preparation: a micro-CT analysis.

AIM: To evaluate oval root canal preparation using one or two instruments in counterclockwise or clockwise reciprocating motion. METHODOLOGY: The radiographic diameter of mandibular human incisors was evaluated, and oval canals were selected (2 ≤ Diameter Ratio ≤ 4). Fifty-seven teeth were assigned to root canal preparation (n = 19): Reciproc 40 (R40) in a counterclockwise reciprocating motion; Mtwo size 40, .06 taper (M 40.06) in a clockwise reciprocating motion or Mtwo size 20, .06 taper and size 40, .06 taper (M 20/40.06) in a clockwise reciprocating motion. Mtwo instruments were coupled to an ENDO DUAL motor, turning 150° clockwise and 30° counterclockwise. Scanning was performed before and after root canal preparation using a SkyScan 1176 micro-computed tomography. Volume, percentage of debris and percentage of uninstrumented surface were analysed in the entire root canal and in each third of the canal. Data were compared using anova and Tukey's tests or Kruskal-Wallis and Dunn tests. RESULTS: The Reciproc and Mtwo systems using different kinematics were associated with a similar increase in root canal volume. Additionally, both system had similar percentage of uninstrumented surface (P > 0.05). Mtwo size 20, .06 taper and size 40, .06 taper was associated with significantly lower debris (P < 0.05) in the middle third (0.56%) when compared to R40 (1.31%) and M size 40, .06 taper (1.54%). CONCLUSIONS: The conventional reciprocation motion for R40 and the clockwise reciprocation motion for Mtwo resulted in similar root canal preparations. Less remaining debris was present in the middle third when two instruments with different diameters were used.

Torsional fatigue resistance of pathfinding instruments manufactured from several nickel-titanium alloys.

AIM: To evaluate the torsional properties of pathfinding nickel-titanium (NiTi) rotary instruments manufactured from several NiTi alloys, ProGlider (M-wire), Hyflex GPF (conventional NiTi Wire and controlled memory wire), Logic (conventional NiTi wire and controlled memory wire) and Mtwo (conventional NiTi wire). METHODOLOGY: A total of 56 NiTi instruments from Glidepath rotary systems (n = 8) were used: Logic (size 25, .01 taper), Logic CM (size 25, .01 taper), ProGlider (size 16, .02 taper), Hyflex GPF (size 15, .01 taper), Hyflex GPF CM (size 15, .02 taper; size 20, .02 taper) and Mtwo (size 10, .04 taper). The torsion tests were performed based on ISO 3630-1 (1992). Three millimetres of each instrument tip was clamped to a small load cell by a lever arm linked to the torsion axis. Data were analysed using a one-way analysis of variance (anova) and Tukey test with a significance level at a = 5%. RESULTS: The Logic size 25, .01 taper had significantly higher torsional strength values (P < 0.05). The ProGlider was significantly different when compared with Hyflex GPF size 15, .01 taper and size 15, .02 taper (P < 0.05). The Logic CM size 25, .01 taper had significantly higher torsional strength than Hyflex GPF size 15, .01 taper and size 15, .02 taper (P < 0.05). No difference was found amongst Mtwo size 10, .04 taper and Hyflex GPF groups (size 15, .01 taper; size 15, .02 taper; size 20, .02 taper). In relation to the angle of rotation, Logic CM size 25, .01 taper and Hyflex GPF size 15, .01 taper had the highest angle values (P < 0.05). The ProGlider had the lowest angle values in comparison with all the groups (P < 0.05) followed by Mtwo size 10, .04 taper. The Logic size 25, .01 taper had significantly higher angle of rotation values than ProGlider and Mtwo size 10, .04 taper (P < 0.05). CONCLUSION: The Logic size 25, .01 taper instrument made of conventional NiTi alloy had the highest torsional strength of all instruments tested. In addition, the ProGlider instrument manufactured from M-Wire alloy had the lowest angle of rotation to fracture in comparison with the other instruments.

Cytotoxicity of peracetic acid: evaluation of effects on metabolism, structure and cell death.

AIM: To evaluate the cytotoxicity and the mechanism of cell aggression of peracetic acid (PA) in comparison with sodium hypochlorite (NaOCl). METHODOLOGY: L929 fibroblasts were exposed to 1% PA and 2.5% NaOCl, at several dilutions for 10 min. The following parameters were evaluated: cell metabolism by methylthiazol tetrazolium assay, external morphology by scanning electron microscopy, ultrastructure by transmission electron microscopy, the cytoskeleton by means of actin and α-tubulin labelling, and the type of cell death by flow cytometry (apoptosis/necrosis). The data were analysed by two-way anova and the Bonferroni post-test (α = 0.05). RESULTS: The PA group had lower cell viability and a higher percentage of necrotic cells than the NaOCl group (P < 0.05). Both solutions diminished cell metabolism, led to destructuring of the cytoskeleton, created changes in the external morphology, resulted in the accumulation of proteins in the rough endoplasmic reticulum and induced cell death predominantly by necrosis. However, these changes were observed in lower doses of PA when compared with NaOCl. CONCLUSIONS: Although they had the same mechanism of cytotoxicity, 1% PA had greater cytotoxic potential than 2.5% NaOCl.

Zirconium oxide and niobium oxide used as radiopacifiers in a calcium silicate-based material stimulate fibroblast proliferation and collagen formation.

AIM: To evaluate the influence of the addition of microparticulate (micro) and nanoparticulate (nano) zirconium oxide (ZrO2 ) and niobium pentoxide (Nb2 O5 ) to a calcium silicate-based cement (CS) on the subcutaneous healing process in rats compared with MTA Angelus™. METHODOLOGY: In each rat, two polyethylene tubes filled with the following materials: (i) MTA; (ii) CS + ZrO2 micro; (iii) CS + ZrO2 nano; (iv) CS + Nb2 O5 micro or (v) CS + Nb2 O5 nano were implanted subcutaneously; empty polyethylene tubes were used in the Control group. After 7, 15, 30 and 60 days, the specimens (n = 5 per group in each period) were fixed and embedded in paraffin. Masson's trichrome sections were used to obtain the volume density of the inflammatory cells (VvIC) and fibroblasts (VvFb). The sections were also stained with Picrosirius-red to calculate the birefringent collagen content. Fibroblast growth factor-1 (FGF-1) was detected by immunohistochemistry, and the number of immunolabelled cells was obtained. The data were subjected to two-way anova followed by Tukey's test (P ≤ 0.05). RESULTS: At all periods, the VvIC was significantly lower (P < 0.001) in all the CS and Control groups than in the MTA group. At all periods, the VvFb was reduced significantly (P = 0.023) in the MTA group in comparison with the other groups. In addition, the number of immunolabelled cells in the capsules of the CS groups was significantly higher (P < 0.001) than in the MTA group at all time-points. CONCLUSIONS: The experimental materials (CS + ZrO2 and CS + Nb2 O5 ) induced fibroblast proliferation and accelerated the regression of the inflammatory reaction. However, the addition of nanoparticulate radiopacifiers did not improve the biological properties of a calcium silicate-based cement when compared to microparticulate agents.

Biocompatibility and mineralized nodule formation of Neo MTA Plus and an experimental tricalcium silicate cement containing tantalum oxide.

AIM: To evaluate the biocompatibility and mineralized nodule formation of an experimental tricalcium silicate cement with tantalum oxide (TSC/Ta2 O5 ) as radiopacifier, Neo MTA Plus (Avalon Biomed Inc., Bradenton, FL, USA) and MTA (Angelus, Londrina, PR, Brazil) on human osteoblast-like cells (Saos-2). METHODOLOGY: Biocompatibility was evaluated by 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide (MTT) and neutral red (NR) assays, after exposure of Saos-2 to cement extracts at 1 : 1, 1 : 2, 1 : 4 and 1 : 8 dilutions for 24 h. Bioactivity was evaluated by alkaline phosphatase (ALP) activity, and calcium deposits were detected with alizarin red staining (ARS). Statistical analysis was performed with analysis of variance and Bonferroni or Tukey post-test (α = 0.05). RESULTS: The MTT assay revealed lower cytotoxicity for NEO and MTA (P < 0.05), and higher for TSC/Ta2 O5 at 1 : 1 and 1 : 2 dilutions when compared to serum-free medium - control (P > 0.05). At 1 : 4 dilution, the TSC/Ta2 O5 cytotoxicity was similar to the control (P > 0.05). At 1 : 8 dilution, cell viability was significantly greater than the control (P < 0.05). Saos-2 cell viability performed using the NR assay at all dilutions revealed no cytotoxic effect of MTA, NEO and TSC/Ta2 O5 . ALP activity at 1 and 3 days was similar to the control (P > 0.05). TSC/Ta2 O5 had significantly greater ALP activity at 7 days when compared with the control (P < 0.05). All materials induced the production of mineralized nodules, and NEO produced significantly more mineralized nodules than MTA and TSC/Ta2 O5 (P < 0.05). CONCLUSIONS: Neo MTA Plus and TSC/Ta2 O5 were biocompatible and induced ALP activity in Saos-2 cells. Both materials induced mineralized nodule formation by Saos-2 with Neo MTA Plus producing significantly more.

An assessment of the overexpression of BMP-2 in transfected human osteoblast cells stimulated by mineral trioxide aggregate and Biodentine.

AIM: To evaluate the effect of MTA and Biodentine on viability, osteogenic differentiation and BMP-2 expression in osteogenic cells. METHODOLOGY: Saos-2 cells were used as a model of osteoblastic cells. Overexpression of BMP-2 was induced by transfection of a CMV-driven plasmid construct including the human BMP-2 coding sequence, and stably transfected cells were selected. Cell viability was assessed by the mitochondrial dehydrogenase enzymatic (MTT) assay. The bioactivity of the materials was evaluated by the alkaline phosphatase (ALP) assay and detection of calcium deposits with alizarin red staining (ARS). The gene expression of BMP-2 and ALP was quantified with real-time PCR. Statistical analysis was performed with analysis of variance and Bonferroni or Tukey post-test (α = 0.05). RESULTS: Viability tests revealed that MTA and Biodentine were not cytotoxic at the higher dilution (1 : 8) to BMP-2-transfected cells. MTA and Biodentine exhibited the highest ALP activity when compared to the Saos-BMP-2-unexposed control group (P < 0.05). Cell exposure to Biodentine and MTA had a significant stimulatory effect on the formation of mineralized nodules (P < 0.05). The highest increase in BMP-2 gene expression was observed after 3 days of BMP-2-transfected cells exposure to MTA and Biodentine in non-osteogenic medium in relation to Saos-BMP-2-unexposed control cells (P < 0.05). Exposure of cells to MTA in osteogenic medium for 1 day increased ALP gene expression by approximately 1.3-fold in relation to Saos-BMP-2-unexposed control cells (P < 0.05). CONCLUSIONS: Both MTA and Biodentine showed biocompatibility and bioactivity in Saos-BMP-2 overexpressing cells. Biodentine had a significantly greater effect on mineralization than MTA. Both MTA and Biodentine enhanced BMP-2 mRNA expression in the transfected system. Both MTA and Biodentine are suitable materials to improve osteoblastic cell mineralization.

Use of micro-computed tomography for the assessment of periapical lesions in small rodents: a systematic review.

This systematic review aimed to evaluate the literature on the acquisition-, reconstruction- and analysis parameters of micro-computed tomography (micro-CT) for the assessment of periapical lesions in rats and mice, and to illustrate the effect of variation in these parameters. The PubMed database was searched from 2000 to January 2015 (English-language publications) for reports on the use of micro-CT to evaluate periapical lesions in rats and mice. QUADAS criteria were used to rate the quality of the studies. To illustrate the effect of variations in acquisition-, reconstruction-, and analysis parameters on images of periapical lesions, micro-CT examination of two hemi-mandibles of mice, with periapical lesions around the first molar was undertaken. Twenty-one studies were identified, which analysed periapical lesions in rats or mice using micro-CT. According to the QUADAS, no study was classified as high-, seven were classified as moderate-, and 14 as low quality. The effect of variation in parameters was that voxel size may interfere with image sharpness, reconstruction may interfere with image sharpness and contrast, and inadequate plane orientation may alter the size of the periapical lesion. Nonpersonalized ROIs resulted in areas that were not part of the periapical lesion. Changing the limits of the threshold for bone-tissue visualization increased lesion size. There is no defined protocol for acquiring and analysing micro-CT images of periapical lesions in rats and mice. Furthermore, acquisition-, reconstruction- and analysis parameters are not adequately explained, which may compromise the scientific impact of the studies.

Human dental pulp cells response to mineral trioxide aggregate (MTA) and MTA Plus: cytotoxicity and gene expression analysis.

AIM: To investigate the cytotoxicity, osteogenic bioactivity and mRNA expression of osteogenic markers of bone morphogenetic protein 2 (BMP-2), osteocalcin (OC) and alkaline phosphatase (ALP) induced by the extracts of set MTA Plus (MTA P) (Avalon Biomed Inc. Bradenton, FL, USA) in comparison with MTA (Angelus, Londrina, PR, Brazil) on human dental pulp cells (hDPCs). METHODOLOGY: Cell viability was assessed by mitochondrial dehydrogenase enzymatic (MTT) assay, and the mechanism of cell death was evaluated by flow cytometry. Bioactivity was evaluated by alkaline phosphatase (ALP) assay and detection of calcium deposits with alizarin red staining (ARS). The gene expression of BMP-2, OC and ALP was quantified with real-time PCR. Statistical analysis was performed with analysis of variance and Bonferroni or Tukey post-test (α = 0.05). RESULTS: MTA and MTA P were not cytotoxic and did not induce apoptosis. MTA P had significant higher ALP activity in relation to MTA and the control (P < 0.05). MTA had a significantly higher percentage of mineralized area than MTA P (P < 0.05). The expression of BMP2 and OC mRNA was significantly higher in cells exposed to MTA than MTA P after 1 day (P < 0.05). At day 3, the mRNA expression of ALP was significantly higher in MTA P compared with MTA (P < 0.05). CONCLUSIONS: MTA and MTA Plus were noncytotoxic, increased mineralization processes in vitro and induced the expression of osteogenic markers.

Bioactivity of MTA Plus, Biodentine and an experimental calcium silicate-based cement on human osteoblast-like cells.

AIM: To compare the bioactivity of Biodentine (BIO, Septodont), MTA Plus (MTA P, Avalon) and calcium silicate experimental cement (CSC) with resin (CSCR) associated with zirconium (CSCR ZrO2 ) or niobium (CSCR Nb2 O5 ) oxide as radiopacifiers. METHODOLOGY: According to the relevance of osteoblastic cell response for mineralized tissue repair, human osteoblastic cells (Saos-2) were exposed to test materials and assessed for viability (MTT), cell proliferation, gene expression of alkaline phosphatase (ALP) osteogenic marker by real-time PCR (RT-qPCR), ALP activity assay and alizarin red staining (ARS) to detect mineralization nodule deposition in osteogenic medium. Unexposed cells acted as the control group (C). Statistical analysis was carried out using ANOVA and the Bonferroni post-test (P < 0.05). RESULTS: All tested cements showed dose-dependent responses in cell viability (MTT). Exposed cells revealed good viability (80-130% compared to the control group) in the highest dilutions of all types of cement. MTA P, BIO and CSCR ZrO2 significantly increased the velocity of cell proliferation after three days of cell exposure in the wound-healing assay (P < 0.05), which corroborated MTT data. On day 3, the ALP transcript level increased, especially to CSCR Nb2 O5 (P < 0.05). All cements exhibited suitable ALP enzyme activity, highlighting the 7-day period of cell exposure. ARS, CSCR Nb2 O5 , revealed a significant potential to induce mineralization in vitro. CONCLUSIONS: All materials had suitable biocompatibility and bioactivity. The MTA P, BIO and CSCR ZrO2 groups had the highest viability rates and velocity of proliferation whilst the CSCR Nb2 O5 group produced more mineralized nodules.

Porosity and sealing ability of root fillings with gutta-percha and BioRoot RCS or AH Plus sealers. Evaluation by three ex vivo methods.

AIM: To investigate the ability of BioRoot RCS, a tricalcium silicate-based root canal sealer and AH Plus to effectively fill the root canals of contralateral teeth using three evaluation methods, and to investigate also the correlation between the methods. METHODOLOGY: The prepared root canals of ten pairs of contralateral mandibular premolar teeth were filled with gutta-percha and sealer using lateral compaction. The percentage of voids within the root canal was assessed by micro-computed tomography, whilst sealing ability was investigated by fluid transport and leakage of fluorescent microspheres. The interaction of sealer with dentine, and sealer penetration were assessed by confocal microscopy. The void volume, fluid flow, microsphere leakage and sealer interaction with dentine for both materials were compared. Nonparametric (Mann-Whitney) tests were used to compare the % void and fluid transport of the two sealers. Spearman correlation was used to assess the pairwise relationships between the techniques. The level of significance was set to 0.05. RESULTS: BioRoot RCS exhibited significantly more percentage of voids than AH Plus. There was no difference in fluid flow and microsphere penetration. BioRoot RCS exhibited a different pattern of sealer penetration and interaction with the dentine walls compared to AH Plus. For both materials, the pairwise correlations between the three techniques were close to zero, indicating weak relationships. CONCLUSIONS: MicroCT analysis revealed a higher void volume for BioRoot RCS. The other techniques did not show a difference between the sealing ability of the sealers. The correlation between the three ex vivo methods of assessment was weak demonstrating their complementarity rather than their concordance.