Morphological and immunohistochemical analysis of the biocompatibility of resin‐modified cements

The aim of this double‐blind randomized study was to evaluate the biocompatibility of resin‐modified glass ionomer cements (RMGIC) by means of morphological and immunohistochemical analyses. RMGICs were selected and divided into four groups: Group CK (Crosslink Orthodontic Band Cement); Group RS (Resilience Light Cure Band Cement) Group RMO (RMO Band Cement), Group TP (Transbond Plus Light Cure Band), and Group C (Control‐polyethylene). The materials were implanted in rat subcutaneous tissues, randomly selected for this study. After time intervals of 7, 15, and 30 days the tissues were submitted to morphological analysis. In immunohistochemical analysis, the immuno‐marking of antibody CD68 was evaluated. The results obtained were statistically analyzed by the Kruskal–Wallis and Dunn tests (p < .05). In the morphological analysis after 7 days, Groups RS, RMO and TP showed more intense inflammatory infiltrate (p = .004) and only Group RMO presented greater intensity of multinucleated giant cells (p = .027). In the immunohistochemical analysis, Groups RMO and RS were observed to present a larger quantity of CD68+ (p = .004) in the time interval of 7 days and only Group RMO presented statistically significant difference for this parameter after 15 days (p = .026). In the time interval of 30 days, Group RMO presented the largest quantity of multinucleated giant cells (p < .004). The RMGICS Crosslink and Transbond Plus provided significantly better tissue biocompatibility than the Resilience and RMO Cements.     

Effect of Chenopodium ambrosioides on the healing process of the in vivo bone tissue

The focus of this double‐blind randomized study was on evaluating the effect of an aqueous extract of Mastruz (Chenopodium ambrosioides L.) on the bone repair process in vivo. In total, 36 male Wistar rats were randomly selected for this study, and divided into 3 groups (n = 12): Group HS (Hemostatic Sponge), Group SM (Hemostatic Sponge with Mastruz) and Group BC (Blood Clot). In each animal, bone defects measuring 2 mm in diameter were performed in both tibias for placement of the substances. After 3 and 10 days, the animals were sacrificed, and the tissues were analyzed under an optical microscope relative to the following events: inflammatory infiltrate; necrosis; young fibroblasts; osteoclastic and osteoblastic activity; endosteal and periosteal bone formation; and bone repair. The results were assessed by using Kruskal–Wallis and Mann–Whitney tests (p < .05). Inflammatory infiltrate demonstrated difference between Groups SM and BC in the time interval of 3 days (p = .004); an event related to the presence of the fibrin sponge and liquid of the extract, which induced a foreign body initial reaction. The presence of young fibroblasts (p = .003), osteoclastic (p = .003), and osteoblastic (p = .020) activity was statistically significant between Groups HS and BC in the time interval of 10 days; performance was related to the presence of the sponge within bone. As regards injured bone tissue repair, Group SM demonstrated a higher level of regenerative capacity (p = 0.004), due to a larger quantities of endosteal and periosteal bone formation, demonstrated in Group SM. The aqueous extract of mastruz stimulated bone neoformation, presenting wound closure with bone tissue at the end of 10 days.     

Histological analysis of biocompatibility of different surgical adhesives in subcutaneous tissue

The focus of this study was to test the hypothesis that there would be no difference between the biocompatibility of cyanoacrylate‐based adhesives in rat subcutaneous tissues. In total, 60 male Wistar rats were used, and divided into four groups (n = 15): Group C (control, PVA‐polyvinyl alcohol sponge), Group NO (N‐butyl‐2‐octylcyanoacrylate), Group NH (n‐hexyl‐cyanoacrylate), and Group EC (Ethyl‐cyanoacrylate). The animals were sacrificed after time intervals of 7, 15, and 30 days and tissues were analyzed under optical microscope as regards the events of inflammatory infiltrate, edema, necrosis, granulation tissue, giant cells, young fibroblasts, and collagen formation. The results were statistically analyzed by the Kruskal–Wallis and Dunn tests (p < .05). Significant inflammatory infiltrate was shown for all the adhesives in the time intervals of 7 (p = .004) and 15 days (p = .003). In the time interval of 30 days, moderate inflammatory infiltrate was observed in Groups NH and EC, with significant difference from Control (p = .001). The quantity of collagen fibers in all the experimental groups showed significant difference compared with Control in the time intervals of 7 (p = .002) and 15 days (p = .001), at 30 days only Group EC showed a smaller quantity of collagen fibers in comparison with Control (p = .001). The hypothesis was rejected. The adhesive N‐butyl‐2‐octylcyanoacrylate had less influence on the inflammatory intensity of multinucleated giant cells. Ethyl‐cyanoacrylate demonstrated the lowest level of biocompatibility among the adhesives, but its use in clinical practice may be promising for coaptation of smaller edges of superficial tissue. Surgical adhesives were shown to be feasible for clinical use in substitution of conventional suturing. Ethyl‐cyanoacrylate should be used with caution due to its greater influence on tissues.     

Effect of chitosan and Dysphania ambrosioides on the bone regeneration process: A randomized controlled trial in an animal model

The focus of this triple‐blind study was on evaluating the effect of chitosan combined with Dysphania ambrosioides (A) extract on the bone repair process in vivo. In total, 60 male Wistar rats (Rattus norvegicus albinus) weighing between 260 and 270 g were randomly selected for this study and distributed into four groups (n = 15). Group C (chitosan), Group CA5 (chitosan + 5% of D. ambrosioides), Group CA20 (chitosan + 20% of D. ambrosioides), and Group CO (Control‐Blood clot). In each animal, bone defects measuring 2 mm in diameter were performed in both tibias for placement of the substances. After 7, 15, and 30 days, the animals were sedated and sacrificed using the cervical dislocation technique and the tissues were analyzed under optical microscope relative to the following events: inflammatory infiltrate, necrosis, osteoclasts, osteoblasts, fibroblasts, periosteal, and endosteal bone formation. The data were evaluated to verify distribution using the Kolmogorov–Smirnov test, and variance, using the Levene test; as distribution was not normal, data were subjected to the Kruskal–Wallis and Dunn nonparametric tests (p < .05). A significant inflammatory infiltrate was observed in Group CA5 (p = .008) in the time interval of 7 days, and in Group C at 15 (p = .009) and 30 (p = .017) days. Osteoblastic activity was more significant in Group CA20 (p = .027) compared with CA5 in the time interval of 7 days. Group CA20 demonstrated a significantly higher endosteal and periosteal bone formation value in the time interval of 7 (p = .013), 15 (p = .004), and 30 days (p = .008) compared with the other groups. The null hypothesis was refuted, bone regeneration was faster in spheres with an association of chitosan and 20% extract, and complete bone repair occurred clinically at 15 days and histologically at 30 days. The spheres proved to be a promising method for the biostimulation of alveolar bone repair and bone fractures.     

Effect of low-level laser therapy on intramembranous and endochondral autogenous bone grafts healing

The aim of this study was to evaluate the healing process of intramembranous (IM) and endochondral (EC) bone grafts under low‐level laser therapy (LLLT). Male rabbits underwent onlay autogenous bone grafts (1 cm in diameter) retrieved from the calvaria and iliac crest and fixed on parietal bones, divided into four groups: Calvaria (C), Iliac (I), Calvaria + LLLT (C+L), and Iliac + LLLT (I+L). Animals from C+L and I+L Groups had their grafts exposed to LLLT (AlGaAs–808 nm, CW, 30 mW, 0.028 cm² average laser beam area), 15 s irradiation time (16 J/cm² per point–total of 64 J/cm² per session). After 7, 14, 30, and 60 days, grafts were retrieved and resorption pattern analyzed by means of morphometry and TRAP‐positive osteoclasts detection. Differences in the resorption levels of iliac grafts were observed, presenting 40% in I group against 8% in I+L grafts at the 14th day of evaluation (P < 0.05). After 30 days, resorption was maintained at 41% in I group, whereas I+L presented 15% in the same period (P = 0.0591). No significant differences were noted in the rates of calvaria grafts resorption in all periods. A significant higher number of osteoclasts on the grafts' surface was observed in C+L Group at day 30, in comparison with C group. In I+L Group, prevalence of osteoclasts was marked at day 7 (P < 0.05) in comparison to I Group. In general, it was concluded that biomodulative effects of LLLT did not significantly affect healing and resorption processes of autogenous bone grafts from EC and IM origins. Microsc. Res. Tech. 75:1237–1244, 2012. © 2012 Wiley Periodicals, Inc.     

Morphology of sealant/enamel interface after surface treatment with bioactive glass

The purpose of this study was to analyze, by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), the morphology of sealant/enamel interface after surface treatment with Biosilicate. Before pits and fissures sealing, the occlusal surfaces of 10 sound human molars were sectioned perpendicularly at the fissures in order to obtain three slices for each tooth. Slices were randomly assigned into three groups (n = 10) according to sealing protocol: Group 1‐ Acid etching + Biosilicate + glass ionomer‐based sealant (Clinpro XT Varnish, 3M ESPE); Group 2‐ Acid etching + glass ionomer‐based sealant (Clinpro XT Varnish, 3M ESPE); Group 3‐ No sealing. All slices were subjected to thermal cycling (5,000 cycles; 5–55°C; dwell time: 30s). Half of the slices from each group (n = 5) were analyzed by CLSM and the other half by SEM. Groups 1 and 2 were also submitted to EDS analysis and their data were evaluated by Two‐Way ANOVA e Tukey's test (α=5%). EDS data analysis showed higher amounts of silicon (Si) ions than calcium (Ca) ions in Group 1 (P < 0.05); Group 2 presented higher amounts (P < 0.05) of Ca ions than Si ions. It may be concluded that the use of Biosilicate for surface treatment did not affect the morphology of glass ionomer‐based sealant/enamel interfaces. Microsc. Res. Tech. 78:1062–1068, 2015. © 2015 Wiley Periodicals, Inc.     

Analysis of efficacy of the self‐assembling peptide‐based remineralization agent on artificial enamel lesions

The objective of this in vitro study was to analyze and compare the biomimetic remineralizing efficacy of the self‐assembling peptide (P11‐4) with agents containing casein phoshopeptide‐amorhous calcium phosphate fluoride (CPP‐ACFP) and sodium fluoride (NaF) on artificial caries lesions using DIAGNOdent and micro‐computed tomography (μCT). Artificial enamel lesions were prepared on extracted impacted sound mandibular third molars. The samples were randomly allocated to four groups (n = 8): Group 1, P11‐4 (Curodont Repair, Credentis AG, Switzerland); Group 2, CPP‐ACFP (MI Varnish, GCCo., Japan); Group3, NaF (Duraphat Varnish, Colgate, Colgate‐Palmolive, NY, USA); Group 4, artificial saliva (control). The agents were applied to demineralized surfaces according to manufacturers' instructions; all specimens were stored in artificial saliva for 1 month. Demineralization and remineralization on enamel surfaces were analyzed and quantified by DIAGNOdent (KaVo, Germany) and μCT (SkyScan1174, Belgium) for lesion depth/area/volume/mineral density (MD). The remineralization efficacy of the agents was evaluated by DIAGNOdent on 1st, 7th, 30th days and by μCT on 30th day. Data were statistically analyzed by ANOVA, Kruskal–Wallis, T test, and Wilxocon tests. The highest remineralization efficacy findings in all periods were determined in Group 1, followed by Groups 2, 3, and 4. The remineralization findings for fluorescence, MD, lesion depth in Group 1 were found significantly higher (p < 0.01) than Group 3; and no significant differences (p > 0.05) were found between Groups 1–2 and Groups 2–3. The area and volume change values in Groups 1, 2, and 3 have shown no significancy (p > 0.05). A significant correlation (p < 0.01) was found between μCT and DIAGNOdent methods. The data of this study have demonstrated that P11‐4 has showed the best remineralization efficacy, followed by CPP‐ACFP and NaF. It is concluded that self‐assembling peptide‐based remineralization agent can be used successfully for biomimetic remineralization of enamel subsurface lesions.     

Different bacterial models for in vitro induction of non‐cavitated enamel caries‐like lesions: Microhardness and polarized light miscroscopy analyses

The aim of this study was to compare different bacterial models for in vitro induction of non‐cavitated enamel caries‐like lesions by microhardness and polarized light microscopy analyses. One hundred blocks of bovine enamel were randomly divided into four groups (n = 25) according to the bacterial model for caries induction: (A) Streptococcus mutans, (B) S. mutans and Lactobacillus acidophilus, (C) S. mutans and L. casei, and (D) S. mutans, L. acidophilus, and L. casei. Within each group, the blocks were randomly divided into five subgroups according to the duration of the period of caries induction (4–20 days). The enamel blocks were immersed in cariogenic solution containing the microorganisms, which was changed every 48 h. Groups C and D presented lower surface hardness values (SMH) and higher area of hardness loss (ΔS) after the cariogenic challenge than groups A and B (P < 0.05). As regards lesion depth, under polarized light microscopy, group A presented significantly lower values, and groups C and D the highest values. Group B showed a higher value than group A (P < 0.05). Groups A and B exhibited subsurface caries lesions after all treatment durations, while groups C and D presented erosion‐type lesions with surface softening. The model using S. mutans, whether or not it was associated with L. acidophilus, was less aggressive and may be used for the induction of non‐cavitated enamel caries‐like lesions. The optimal period for inducing caries‐like lesions was 8 days. Microsc. Res. Tech. 78:444–451, 2015. © 2015 Wiley Periodicals, Inc.     

Remineralization effects of self-assembling peptide P11-4 associated with three materials on early enamel carious lesions: An in vitro study

The aim of this study was to assess the remineralization of enamel caries lesions using the self-assembling peptide P₁₁-4 associated with different materials. Artificial early enamel lesions were prepared on 154 primary teeth. The samples were randomly divided into eight groups: (1) control, (2) P₁₁-4, (3) fluoridate toothpaste (FT), (4) P₁₁-4 + FT, (5) casein phosphopeptide–amorphous calcium phosphate (CPP–ACP), (6) P₁₁-4 + CPP–ACP, (7) fluoridate bioactive glass toothpaste (BT), and (8) P₁₁-4 + BT. The surface enamel microhardness (EMH) and energy-dispersive X-ray spectroscopy (EDS) of the teeth were then measured at the baseline, after demineralization, and after 28 days of remineralization. The enamel surfaces were assessed by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The data were analyzed with one-way analysis of variance (ANOVA) (p < .05). EMH after demineralization was significantly lower than the baseline value (p < .001). The interventions led to an enhanced percentage of EMH recovery (%REMH), which was higher in Groups 6 and 7. There was no significant difference between Groups 3 and 4. Groups 1 and 2 had the lowest %REMH. The mean calcium/phosphate weight percentage ratio of P₁₁-4 was significantly lower than the others (p < .001). The FESEM and AFM images revealed mineral deposition on the eroded enamel and reductions in surface roughness in Groups 5 and 7.     

Microtensile strength of resin cement bond to indirect composite treated by different output powers of Er:YAG laser

The study aimed to evaluate the effect of different output powers of Er:YAG laser on microtensile bonding strength of indirect composite to resin cements.36 indirect composite blocks (GC Gradia DA2, Japan) size 15 × 10 × 10 mm³ were constructed, and divided into 12 groups, as follows:G1: control group (no treatment); Groups G2 to G6: treated with Er:YAG laser (2,940 nm) in noncontact mode, frequency 20 Hz, pulse duration 470 µs, with output power ranging from 2W to 6W; Groups G7 sandblasting, Groups 8 to G12: as Groups G2 to G 6 with preparatory sandblasting. One specimen from each group was analyzed by SEM; each specimen was fixed to a specialized metal jig using cyanoacrylate (Mitreapel, Beta Kimya San. Ve TIC, Iran) and debonded under tension with a universal testing machine (Zwick, Germany) at a crosshead speed of 0.5 mm min^?1. Sandblasting and laser can improve bond strength above an energy level of 150 mJ. SEM evaluation of laser‐treated specimens showed irregularities and deep undercuts. T test analysis showed no significant difference between sandblasted and non‐sandblasted group, with laser output power of 0, 100, or 150 mJ (P = 0.666, P = 0.875, and P = 0.069); in the specimens irradiated with energy output of 200, 250, or 300 mJ, sandblasted specimens showed higher bond strength than non‐sandblasted ones. The results demonstrate that, in composite resin irradiated with laser at energy output of 200–300 mJ, sandblasting might be a suitable procedure to enhance bond strength of resin cement. Microsc. Res. Tech. 79:328–333, 2016. © 2016 Wiley Periodicals, Inc.     

Antibacterial activity of glass ionomer cement modified by zinc oxide nanoparticles

This study evaluated the antibacterial activity of zinc oxide nanoparticles incorporated into self‐cured glass ionomer cement (GIC) and light‐cured resin‐reinforced GIC on Streptococcus mutans biofilm. The GICs, Fuji II (GC America) and Fuji II LC (GC America), were incorporated with nanoparticles at concentrations of 0%, 1%, and 2% by weight, and the biofilm maturation time was one and seven days. Circular specimens of each GIC type were prepared. The antibacterial activity was evaluated by determining the number of colony forming units of S. mutans strain per milliliter. Morphology of the biofilm was analyzed by scanning electron microscopy (SEM). The data obtained for each GIC were analyzed by two‐way ANOVA (α = 5%). For chemically activated GIC, no significant difference was observed in relation to the time of biofilm maturation (p = 0.744), concentration of nanoparticles (p = 0.966), and their interaction (p = 0.800). The results from analysis of GIC modified by light‐polymerized resin showed that only of the maturing time significantly affected the number of adhered cells on the biofilm (p = 0.034, F = 4.778). The more mature the biofilm, higher the number of cells. SEM analysis showed no change in cell morphology in relation to the type of GIC, maturation time, and nanoparticles concentration. We conclude that the inclusion of zinc oxide nanoparticles at concentrations of 1% and 2% by weight into the GICs evaluated here, did not promote their antimicrobial activity against S. mutans.     

Effect of treatment with simvastatin on bone microarchitecture of the femoral head in an osteoporosis animal model

The objective of this study was to evaluate the microarchitecture and trabecular bone strength at the distal region of the femur, and its biomechanical properties with simvastatin administration with two different doses in ovariectomized (OVX) rats. Ninety rats were divided into six groups to evaluate treatment with the simvastatin drug (n = 15): SH (Sham surgery), SH‐5 (5 mg simvastatin), SH‐20 (20 mg simvastatin), OVX, OVX‐5, and OVX‐20. Euthanasia was performed at three different times, five animals per period: 7, 14, and 28 days. The effectiveness of the treatments was evaluated by mechanical testing and histomorphometric analysis of the femurs. The results of analysis by the linear model of mixed effects showed 20 mg of simvastatin results in increased trabecular bone after 14 days (P = 0.039) of ingestion in ovariectomized animals. However, ingestion of 5 mg of simvastatin is able to sensitize the trabecular bone only at 28 days (P = 0.005) of ingestion. In the mechanical tests stiffness improves within 28 days (P = 0.003). Regarding maximum strength, no statistical differences were observed. According to these results, it can be concluded that for a decrease in oral intake, longer treatment times are required. Microsc. Res. Tech. 79:684–690, 2016. © 2016 Wiley Periodicals, Inc.     

Comparison of different irrigation activation techniques on smear layer removal: An in vitro study

The purpose of this study was to evaluate the efficiency of different irrigation activation techniques on smear layer removal. About 80 single‐rooted human maxillary central teeth were decoronated to a standardized length.The samples were prepared by using ProTaper system to size F4 and divided into eight equal groups (n = 10) according to the final irrigation activation technique; distilled water was used as an irrigant in Group 1. The other groups were treated with 2.5% NaOCl and 17% EDTA, respectively. Conventional syringe irrigation (CSI) was used in Group 2. Irrigation solutions were activated using passive ultrasonic irrigation (PUI, Group 3), EndoVac apical negative pressure (ANP, Group 4), diode laser (Group 5), Nd:YAG laser (Group 6), Er:YAG laser (Group 7), and Er:YAG laser using with photon‐induced photoacoustic streaming (PIPS?, Group 8). Teeth were split longitudinally and subjected to scanning electron microscope (SEM). PIPS showed the best removal of smear layer when compared with PUI, ANP, Nd:YAG, and Er:YAG, but the difference was not statistically significant (P > 0.05). Smear layer scores obtained with PIPS technique were statistically significant different from those of obtained with control, CSI and diode laser groups (P < 0.05). All experimental irrigation techniques except ANP and diode laser removed smear layer more effectively at the coronal and middle levels compared to the apical level (P < 0.05). Irrigation activated/delivered techniques except diode laser have a positive effect on removing of smear layer. Microsc. Res. Tech. 78:230–239, 2015. © 2015 Wiley Periodicals, Inc.     

The effect of fiber insertion on fracture strength and fracture modes in endocrown and overlay restorations

Aim of this study was to determine the fracture strength and modes of endocrown and overlay restorations with/without fiber reinforcement on endodontically treated teeth. Sixty-five molar teeth were used: Group IN (intact teeth), Group E (endocrown), Group ER (endocrown + ribbond), Group O (overlay), Group OR (overlay + ribbond; n = 13). Ribbond (Seattle, WA) was inserted at the base of pulp chamber in Group ER and OR. All restorations were designed and produced by using computer-aided design and computer-aided manufacturing (Sirona Dental Systems, Bensheim, Germany) and Cerasmart (GC Corp. Kasugai, Aichi, Japan). All teeth were subjected to thermomechanical aging and fractured in a universal test device. Fractured surfaces were analyzed with a stereomicroscope (SMZ1000, Nikon, Japan). Data were analyzed with Welch's analysis of variance and Games–Howell test (p < .001). Group E showed significantly lower fracture strength values than other groups(p < .05). No statistically significant differences were found among the other groups(p > .05). Most of the unfavorable fractures were seen in Groups E and O. Overlay restorations showed higher fracture strength values than endocrown restorations. Although fiber insertion did not improve the fracture strength of the indirect restorations, it reduced the frequency of irreparable fracture mode. Overlay restorations and fiber application are more advantageous in preserving the durability of the endodontically treated teeth.     

Ultrastructural changes in the cemento‐enamel junction caused by acidic beverages: An in vitro study

The present in vitro study was aimed at evaluating the morphological changes in the cemento‐enamel junction (CEJ) after exposure to acidic beverages using the scanning electron microscopy (SEM). The initial pH and titratable acidity (TA) was analyzed from follow groups: (I) Coca cola, (II) orange juice, (III) Cedevita, (IV) Red Bull, (V) Somersby cider, and (VI) white wine. The CEJ samples (n = 64), obtained from unerupted third molars, were allocated to one control (artificial saliva, n = 16) and six experimental groups (n = 8). The experimental samples were immersed in beverages (50 ml) for 15 min, three times daily, 10 days, and in artificial saliva between immersions. SEM analysis was performed in a blind manner, according to scoring scale. One‐way ANOVA and Tukey's post hoc tests, as well as Kruskal–Wallis and Mann–Whitney U test used for statistical analysis. The pH values of the acidic beverages ranged from 2.65 (Coca cola) to 3.73 (orange juice), and TA ranged from 1.90 ml (Coca cola) to 5.70 ml (orange juice) of NaOH to reach pH 7.0. The SEM analysis indicated statistically significant differences between the control samples and those immersed in acidic beverages. The Groups IV, I, and II, showed the highest CEJ damage grade while those of the Group VI were the lowest. All the tested acidic beverages caused morphological changes in the CEJ with a smaller or larger exposure of dentine surface, and were not always related to the pH or TA of acidic beverages.     

Does laser etching have an effect on application mode of a universal adhesive?—A microleakage and scanning electron microscopy evaluation

This study aimed to evaluate the microleakage of a universal adhesive's different application modes incorporated with Er,Cr:YSGG laser on Class V resin composite restorations. Sound human molar teeth (n = 30) were used for microleakage evaluations. Specimens with 60 standardized Class V cavities were divided into five groups according to the adhesive modes of universal adhesive, Adhese Universal (n = 12). Group 1‐etch‐and‐rinse mode with phosphoric acid; Group 2‐etch‐and‐rinse mode with Er,Cr:YSGG laser; Group 3‐selective‐etch mode with phosphoric acid; Group 4‐selective‐etch mode with Er,Cr:YSGG laser; Group 5‐self‐etch. After restorations were performed with a resin composite, Tetric N‐Ceram, the specimens were polished and subjected to thermocycling (10,000X). Following immersion in 0.5% basic fuschin for a day, the teeth were sectioned and the degree of microleakage was determined along the tooth‐resin composite interface using a light microscopy(40X). Five specimens from each group were examined by scanning electron microscopy. The Kruskal–Wallis, Siegel Castello, and Wilcoxon tests were used for statistical analyses (α = .05). At the enamel margins, significant differences were obtained among the groups (p < .05). Significantly higher microleakage scores were detected in Group 5 in comparison with Groups 1, 2, and 3. There were no significant differences between different adhesive strategies at the dentin margins (p > .05). While analyzing enamel and dentin microleakage scores, no statistically significant differences were observed in Groups 4 and 5 (p > .05). The laser application time and the adhesive modes of universal adhesives could affect the microleakage at the enamel margins. Different adhesive modes of universal adhesives combined with laser etching had no influence on the microleakage scores of dentin margins.     

Effect of ultrasonic excitation on the porosity of glass ionomer cement: a scanning electron microscope evaluation

Background: Ultrasonic excitation (US) was applied to glass ionomer cement (GIC) during early set time to increase the advantageous properties of this material. Purpose: The aim of this in vitro study was to assess the inner porosity of GIC after US. Study design: A total of 16 specimens, for each material, were prepared from high‐viscosity GIC Fuji IX GP, Ketac Molar, and Ketac Molar Easymix. Half of these specimens (n = 8) received 30 s of US during the initial cement setting. After completion of the material setting, specimens were fractured and observed by scanning electronic microscopy to quantitatively assay porosity inside the material using Image J software. Results: Statistical data analysis revealed that US reduced the porosity for all tested materials (P ≤ 0.05). The following reductions (expressed in percentages) were achieved: Fuji IX—from 3.9% to 2.8%; Ketac Molar Easy Mix—from 4.4% to 2.6%, and Ketac Molar—from 2.4% to 1.6%. Conclusion: Under the tested conditions, US was an effective method for porosity reduction inside the material. Microsc. Res. Tech. 74:54‐57, 2011. © 2010 Wiley‐Liss, Inc.     

Antibacterial efficacy and remineralization capacity of glycyrrhizic acid added casein phosphopeptide‐amorphous calcium phosphate

The aim was to evaluate remineralization capacity and antibacterial efficiency of Tooth Mousse and various amounts of glycyrrhizic acid added Tooth Mousse on primary tooth enamel. Three groups were formed; Group 1 (CPP‐ACP), Group 2 (CPP‐ACP + 5% glycyrrhizic acid), and Group 3 (CPP‐ACP + 10% glycyrrhizic acid) in order to evaluate remineralization capacity. Enamel samples were immersed in demineralization solution and then remineralization agents were applied. Surface microhardness and SEM analyses were performed at the beginning, after demineralization and remineralization. For antibacterial tests, four groups were formed; Group 1, Group 2 and Group 3 and Group 4 (control). Biofilms were then exposed to 10% sucrose eight times per day for 7 days. After biofilm growth period, samples were treated with materials to evaluate antibacterial efficiency except control group. After application of materials, samples were incubated 2 more days at 37°C and at the end of this period, absorbance values of biofilms were determined and data were analyzed. An increase in microhardness values was Group 2 > Group 3 > Group 1, respectively, but there were no significant differences. After remineralization, microhardness values showed significant increases when compared to demineralized groups, but there was no significant difference. All groups showed decreased absorbance value of biofilm when compared with control group but they were insignificant. It was observed that both in Group 2 and Group 3, glycyrrhizic acid did not have a negative effect on remineralization and although they have an increase, it was insignificant. Although glycyrrhizic acid added CPP‐ACP groups showed increased antibacterial activity, they were not statistically significant.     

Calcium supplementation in colorectal cancer prevention: A systematic meta-analysis of adverse events

Despite the multiple systematic reviews and meta-analyses accumulating evidence on the preventive effect of calcium supplementation for colorectal cancer, most of the associated adverse effects are not systematically analyzed. The aim of the study is evaluating adverse events associated with calcium supplementation for colorectal cancer prevention through a systematic meta-analysis. We searched Medline, PubMed Central, EMBASE (Excerpta Medica database), Scopus, Cochrane Central Register of Controlled Trials, and Web of Science published in English from database inception up to 31 July 2019. In the current systematic meta-analysis, we included human studies (including cohort studies, clinical trials, case-control studies) on supplementation of calcium in patients with or at risk of colorectal cancer. Assessment of the quality of included studies was performed by Jadad score. Information on the patient population, number of enrolled subjects in each group, dose of calcium supplementation, duration of calcium supplementation, and reported adverse events were gathered. The data were pooled for incidence rates for any adverse event during the study period regardless of causality association. We identified 6 studies, comprising 4583 participants that met the inclusion criteria. Meta-analysis on pooled incidence rates for adverse event during study period showed no statistically significant increased risk for cancer (OR = 0.92, 95% CI: 0.70–1.21, P = 0.577; I² = 0.0%, P = 0.731), coronary revascularization (OR = 1.12, 95% CI: 0.79–1.59, P = 0.492; I² = 0.0%, P = 0.957), myocardial infarction (OR = 0.81, 95% CI: 0.34–1.91, P = 0.634; I² = 67.9%, P = 0.047), stroke (OR = 0.75, 95% CI: 0.42–1.33, P = 0.332, I² = 0.00%, P = 0.717), Transient Ischemic Attack (TIA) (OR = 1.37, 95% CI: 0.28–6.51, P = 0.692, I² = 81.9%, P = 0.002), urolithiasis (OR = 1.23, 95% CI: 0.75–2.01, P = 0.410; I² = 0.0%, P = 0.851), fracture (OR = 0.98, 95% CI: 0.70–1.37, P = 0.938; I² = 37.8%, P = 0.152) and death (OR = 1.05, 95% CI: 0.71–1.56, P = 0.786, I² = 12.2%, P = 0.317) in patients receiving calcium supplementation for colorectal cancer prevention compared to control. Based on the results of Egger test, publication bias was not observed among the studies (P = 0.262). The current result of the meta-analysis on human studies reporting adverse events associated with calcium supplementation for the prevention of colorectal cancer demonstrated no statistically significant increased risk for the development of adverse events compared to control groups.     

Effect of rotary instrument associated with different irrigation techniques on removing calcium hydroxide dressing

Calcium hydroxide [Ca(OH)₂] residues in root canals may compromise sealing of filling and endodontic treatment success. The aim of this study was to compare the efficacy of using rotary instrument associated with EndoActivator, EndoVac, passive ultrasonic irrigation (PUI), and conventional needle irrigation (CNI), in Ca(OH)₂ removal from root canal, by means of scanning electron microscopy (SEM) images. Sixty‐six human canines were prepared with the Protaper system up to F5 and filled with Ca(OH)₂. After 7 days, Ca(OH)₂ was removed with rotary instrument F5 associated with the irrigation techniques used in each group (n = 15): GI (CNI), GII (EndoVac), GIII (EndoActivator) and GIV (PUI). In all groups 15 mL of 2.5% NaOCl and 3 mL of 17% EDTA were used for Ca(OH)₂ removal. The Ca(OH)₂ residues was evaluated by SEM in the middle and apical third using a system of scores. The results were analyzed by the Kruskal‐Wallis and Dunn tests (α = 0.05). None of the techniques completely removed the Ca(OH)₂ from root canals. There was no difference between EndoActivator, EndoVac and PUI (P > 0.05), but the three techniques removed more Ca(OH)₂ than the CNI (P < 0,05), in the middle and apical thirds of the root canal. It was concluded that the rotary instrument combined with EndoActivator, EndoVac, and PUI was shown to be more efficient than the rotary instrument combined with the CNI in removing Ca(OH)₂ from the root canal. Microsc. Res. Tech. 77:642–646, 2014. © 2014 Wiley Periodicals, Inc.