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Aim: To evaluate the dental pulp response to a novel mineral trioxide aggregate containing phosphorylated pullulan (MTAPPL) in rats after direct pulp capping. Methods: Ninety‐six cavities were prepared in the maxillary first molars of 56 male Wistar rats. The dental pulps were intentionally exposed and randomly divided into four groups according to the application of pulp capping materials: MTAPPL; phosphorylated pullulan (PPL); a conventional MTA (Nex‐Cem MTA, NCMTA; positive control); and Super‐Bond (SB; negative control). All cavities were restored with SB and observed for pulpal responses at 1‐, 3‐, 7‐ and 28‐day intervals using a histological scoring system. Statistical analysis was performed using Kruskal–Wallis and Mann–Whitney U‐test with Bonferroni's correction, and the level of significance was set at 0.05. DMP1 and CD34 antigen were used to evaluate odontoblast differentiation and pulpal vascularization, respectively. Results: On day 1, mild inflammatory cells were present in MTAPPL and NCMTA groups; fewer inflammatory cells were present in the PPL, whereas SB was associated with a mild‐to‐moderate inflammatory response. A significant difference was observed between PPL and SB (p <.05). No mineralized tissue deposition was observed. On day 3, moderate‐to‐severe inflammatory cells were present in PPL and SB, whereas MTAPPL and NCMTA had a mild inflammatory response. Initial mineralized tissue deposition was observed in the NCMTA, MTAPPL and SB. A significant difference was observed between MTAPPL and PPL (p <.05). On day 7, a thin layer of mineralized tissue was observed in all tested groups with no or mild inflammatory response. On day 28, no inflammatory response was observed in MTAPPL, whereas NCMTA, PPL and SB had mild inflammatory responses. A significant difference was observed between MTAPPL and SB (p <.05). Complete mineralized tissue barrier formation was observed in MTAPPL, NCMTA and PPL with no significant difference (p >.05). SB exhibited incomplete mineralized tissue barriers, significantly different from NCMTA, MTAPPL and PPL (p <.05). The staining with CD34 was positive in all the groups on all observation days. Conclusion: The favourable pulpal responses and induction of mineralized tissue formation associated with MTAPPL indicate its potential application as a direct pulp capping material. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the shade matching ability of a novel supra‐nano filled esthetic resin composite employing structural color technology using simplified simulated clinical cavities. Filler morphology and light transmittance characteristics were also evaluated. Materials and Methods: One‐hundred and twenty frames of resin composite were built in A1, A2, A3, and A4 shades to simulate Class I cavities (diameter = 4 mm, height = 2 mm). For each shaded frame, cavities were filled with three different types of filler containing resin composites (n = 10): supra‐nano filled (SN filled) resin composite, microhybrid filled (MH filled) resin composite, and clustered‐nano filled (CN filled) resin composite. Color parameters were calculated using CIELAB (△Eab) and CIEDE2000 (△E00). Data were analyzed using one‐way analysis of variance (ANOVA), followed by Duncan's test (α =.05). Filler morphology and light transmittance characteristics were measured to explore the role of structural color on shade matching. Results: △Eab and △E00 of SN filled resin composite were significantly lower in A2, A3, and A4 shades (P <.05). Conclusions: The SN filled resin composite showed better shade matching with A2, A3, and A4 shades of resin composite frames compared to MH filled resin composite, and CN filled resin composite. Clinical Significance: Universal‐shade resin composites, which were expected to match nearly all shades, simplify the restorative procedure. Resin composite, which contained spherical supra‐nano filler particles, could contribute most to its shade matching by stimulating structural color. Structural color technology may provide additional benefits for shade matching of resin composites. [ABSTRACT FROM AUTHOR]

Using transmission electron microscopy (TEM), this study investigated the characteristics of smear layers after preparation of dentin surfaces using different methods. In addition, this study analyzed, using scanning electron microscopy (SEM), the interactions of smear layers with the various acidic agents used subsequently to treat the dentin surface. Mid‐coronal dentin surfaces were prepared according to one of five instrumentation methods: fracture; grinding with carbide bur; grinding with regular‐grit diamond bur; grinding with superfine‐grit diamond bur; or grinding with 600‐grit silicon carbide (SiC) abrasive paper. Then, each prepared dentin surface was further divided into control (no further treatment) or treatment with one of the following agents: phosphoric acid solution (PAS); phosphoric acid gel (PAG); Clearfil SE Bond 2 Primer (SE2); or Scotchbond Universal Adhesive (SBU). Longitudinal ultra‐thin sections were made for TEM observations. Dentin discs, representing each surface preparation and treatment method described above, were created, and the morphology was examined by SEM. The TEM results revealed differences in thickness and denseness of the smear layer, according to the different methods of instrumentation used to prepare the dentin surface. The two forms of phosphoric acid completely removed the smear layer in all groups. Agglomerated silica particles were observed on the top of the collagen layer after etching with PAG. For all dentin surfaces, except for that prepared with SiC, SE2 demonstrated better etching efficacy on different smear layers, whereas SBU provided only superficial interaction. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of topical fluoride application on enamel hardness after in-office bleaching. Twelve human incisors were cut along the long axis, resulting in 24 halves used in four treatment groups ( n = 6 in each group): (i) untreated group (C); (ii) in-office bleaching material (B); (iii) treatment with surface reaction-type prereacted glass-ionomer varnish after in-office bleaching (B+ PRG); and (iv) treatment with acidulated phosphate fluoride solution after bleaching (B+F). All specimens were subjected to pH-cycling for 4 wk. Knoop hardness was measured using a Cariotester. The decalcification of enamel was assessed quantitatively by measuring the integrated mineral loss (Δ IML). Games-Howell analysis was used to assess statistical significance of between-group differences. The Knoop hardness decreased significantly after bleaching for all groups. In treatment groups B+ PRG and B+F, the Knoop hardness returned to the original unbleached values after the first pH cycle and did not change afterwards. In treatment groups C and B there was a gradual decrease in the Knoop hardness until the fourth pH cycle. The integrated mineral loss, Δ IML, was significantly higher in treatment group B+F after 2 wk than in the other treatment groups. After 4 wk, the Δ IML in treatment group B was significantly higher than in treatment group B+ PRG. The application of fluoride-containing materials after bleaching results in recuperation of hardness to levels similar to those of unbleached enamel. [ABSTRACT FROM AUTHOR]

The buffering capacity and inhibitory effects on enamel demineralization of two commercially available dental sealants were evaluated in this study. The effects of filler particles were also examined. Disks of enamel and cured sealant materials of BeautiSealant (silica or S-PRG filler) or Teethmate F-1 were incubated in lactic acid solutions ( pH 4.0) for 1-6 d. The pH changes and amounts of ions released in the solutions were assessed, and enamel surfaces were observed using a scanning electron microscope. The pH of the solution with BeautiSealant (S-PRG filler) was neutralized from pH 4.0 to pH 6.1 (after incubation for 1 d) and from pH 4.0 to pH 6.7 (after incubation for 6 d). In addition, no release of calcium ions was detected and the enamel surface was morphologically intact in scanning electron microscopy images. However, the pH of the solution with Teethmate F-1 remained below pH 4.0 during incubation from days 1 to 6. Calcium release was increased in solutions up to and after 6 d of incubation. Scanning electron microscopy images showed that the structures of hydroxyapatite rods were exposed at the specimen surfaces as a result of demineralization. Ions released from S-PRG filler-containing dental sealant rapidly buffered the lactic acid solution and inhibited enamel demineralization. [ABSTRACT FROM AUTHOR]

Components of dental composites have been implicated as metabolic and oxidative stressors in cells. Antioxidant colloidal platinum nanoparticles (CPtN) could be useful as nanofillers that reduce cellular stress caused during placement and exposure to unpolymerized composite components. Yet, CPtN may have pro- or anti-oxidative properties depending on the chemical environment in which they are used. This study investigated the ability of CPtN to mitigate mitochondrial or oxidative stress induced by camphorquinone (CQ) and dimethylaminoethyl methacrylate (DMAEM), two components of dental composites that initiate light-activated addition polymerization. THP-1 human monocytic cells were exposed to subtoxic concentrations of CQ and DMAEM, then blue light for 0-60 s. Mitochondrial and oxidative stress were estimated 0, 6, or 24 h after irradiation by measuring cellular ATP or GSH levels, respectively. CPtN (0-20 ppm) were added prior to blue light irradiation. Statistically significant effects were determined by ANOVA with Tukey post-hoc analysis (α = 0.05). Light alone did not alter THP-1 activity, but CQ and DMAEM induced 120% increases in cell ATP levels, which was increased further (50%) by CPtN. Blue light irradiation caused a 50% drop in ATP levels, which increased to 75% when CPtN were added. GSH levels were suppressed by CQ/DMAEM and blue light, and CPtN increased suppression by 20-30%. CPtN did not mitigate mitochondrial or oxidative stress in THP-1, but amplified these stresses under the conditions tested. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011. [ABSTRACT FROM AUTHOR]

Soell M, Hemmerlé J, Hannig M, Haïkel Y, Sano H, Selimovic D. Molecular force probe measurement of antigen I/II-matrix protein interactions. Eur J Oral Sci 2010; 118: 590-595. © 2010 Eur J Oral Sci Viridans streptococci possess a family of immunologically and structurally related cell-surface proteins, termed antigen I/II, which may function as adhesins and enable oral streptococci to adhere to saliva-coated surfaces and matrix proteins. Here we used atomic force microscopy in the molecular force mode to measure the specific interaction forces between antigen I/II and two matrix proteins, collagen and fibronectin. These matrix proteins provide important binding sites for adherence of oral streptococcal in dentinal caries and endocarditis, respectively. Antigen I/II-coated cantilever tips were brought into contact with collagen- or fibronectin-coated silica coverslips. For the protein I/II-fibronectin interaction experiments, the mean strength of the last ruptures was 216 pN, with most of the detachments located around 125 pN. In antigen I/II-collagen interaction experiments, the mean strength of the last rupture forces corresponded to 136 pN, with the most frequent unbinding force around 75 pN. Thus, our findings definitely suggest that, under the present experimental conditions, antigen I/II binds more strongly to fibronectin than to type I collagen. This might be of relevance for the attachment of viridians streptococci to surfaces exposed to strong hydrodynamic shearing forces under in vivo conditions. [ABSTRACT FROM AUTHOR]

Resin–dentin bonds are known to degrade in the relatively aggressive oral environment. In order to obtain greater insight into the interfacial degradation process, we examined, by using transmission electron microscopy (TEM), the interfacial ultrastructure of two adhesives bonded to dentin after 1 yr in vivo. Class V cavities were prepared on the buccal surfaces of 14 intact teeth of two monkeys and then restored by using either the two-step self-etch adhesive, Unifil Bond, or the two-step etch-and-rinse adhesive, Single Bond, in combination with the restorative microhybrid composite, Z250. After 1 yr, 10 other teeth were restored by using the same materials (controls). One day later, the monkeys were killed, following which the microtensile bond strength to dentin was determined and the interfacial ultrastructure was examined by TEM. Whereas no noticeable changes in the morphology of the resin–dentin interface were observed between the 1-d and 1-yr specimens for Unifil Bond, Single Bond exhibited signs of interfacial degradation, in particular at the bottom of the 3 µm-deep hybrid layer. In conclusion, the adhesive interface produced by the etch-and-rinse adhesive was less resistant to degradation than that produced by the self-etch system. [ABSTRACT FROM AUTHOR]

Ikeda T, Sidhu SK, Omata Y, Fujita M, Sano H. Colour and translucency of opaque-shades and body-shades of resin composites. Eur J Oral Sci 2005; 113: 170–173.© Eur J Oral Sci, 2005The purpose of this study was to evaluate the optical properties– not only the translucency but also the colours– of opaque-shade resin composites. The CIELAB parameters (L*, a* and b*) of disks of A2 and opaque A2 (OA2) shades of Charisma (Heraeus-Kulzer), Solare (GC) and Filtek Supreme (3M) were evaluated on backings of black, white and the material itself to calculate the translucency parameter (TP) and the colour differences (ΔE*) between A2 and OA2. A two-way analysis of variance (anova) for the TP indicated a less statistically significant TP value in the OA2 shade than the A2 shade for all products. As for the products, Charisma showed a statistically greater TP value than the other two products. Regarding theΔE* between A2 and OA2, all the products revealed clinically perceptible colour differences (ΔE* > 3.3). Hence, we must take the colour differences of opaque-shade resin composites into consideration, as well as the translucency of the materials, for a clinically acceptable colour match of the restoration. [ABSTRACT FROM AUTHOR]

Abo T, Uno S, Sano H. Comparison of bonding efficacy of an all-in-one adhesive with a self-etching primer system. Eur J Oral Sci 2004; 112: 286–292.© Eur J Oral Sci, 2004 The aim of this study was to compare the bonding efficacy of an all-in-one adhesive with that of a self-etching primer system by measuring microleakage after thermocycling and the microtensile bond strength (μTBS) to enamel and dentin. Circular class V cavities along cement–enamel junctions were prepared in 20 extracted human premolars. Each 10 teeth were bonded with either AD Bond (AD) or Clearfil SE Bond (SE), and filled with a resin composite (Charisma). After thermocycling and staining with 0.5% basic fuchsin, the microleakage at the coronal and apical walls was evaluated using longitudinal sections. In addition 20 premolars were used to measure μTBS at 24 h after bonding for these adhesives to enamel and dentin that corresponded to the coronal and apical walls of the class V cavities. AD showed more microleakage than SE in the coronal walls, but there was less microleakage in the apical walls and no difference in apical leakage between the two adhesives. μTBS (SD) in MPa to enamel and dentin were 25.2 (7.3) and 68.3 (9.4) for AD, and 35.8 (7.4) and 76.4 (7.8) for SE, respectively. AD gave a lower μTBS to enamel than did SE. The results suggested that the poor adaptation at the coronal wall in AD might be caused by the lower bond strength to enamel. [ABSTRACT FROM AUTHOR]

Self-etching primer adhesives have recently been introduced to simplify bonding. However, the fundamental bonding mechanism of self-etching primers to enamel is not yet fully understood. This study aimed to investigate resin–enamel bonds of self-etching primer adhesives on ground enamel. Two self-etching primer adhesives (Clearfil Liner Bond 2 V and Clearfil SE Bond) were used in this study. A total-etch adhesive (One-Step) was used as a control. Resin–enamel beams were subjected to the microtensile bond test. Subsequently, the failure modes of all specimens were quantified using image analysis. Undemineralized and demineralized ultrathin sections of the resin–enamel bonded specimens were examined using transmission electron microscopy. The bond strengths of Clearfil SE Bond (39.8 ± 11.9 MPa) and One-Step (46.2 ± 12.7 MPa) were significantly greater than that of Clearfil Liner Bond 2V (30.4 ± 6.2 MPa). Scanning electron microscopy of the fractured surfaces revealed the failure direction and weakest portion within each bond. Transmission electron microscopy showed a thin hybridized complex of resin in enamel produced by the self-etching primers without the usual micrometer-sized resin tags seen in resin–enamel bonds produced using the total-etch adhesive. The morphological features of the resin–enamel bonds produced by two self-etching primers tested were different from that created with the total-etch adhesive. [ABSTRACT FROM AUTHOR]

Aim Methodology Results Conclusions Calcium hydroxide (CH) has been considered as a direct pulp capping materials (DPC) for the last decades despite having some limitations. Phosphorylate pullulan (PPL) incorporated with CH (CHPPL) is a novel biomaterial that was introduced as a promising DPC material. Thus, the aim of the study was to evaluate the inflammatory response and mineralized tissue formation (MTF) ability of PPL‐based CH formulations on rat molars after DPC.This study consisted of six groups: CH with 1% PPL (CHPPL‐1); 3% PPL (CHPPL‐3); 5% PPL (CHPPL‐5); Dycal and NEX MTA Cement (N‐MTA) as the positive control, and no capping materials (NC). One hundred twenty maxillary first molar cavities were prepared on Wistar rats. After capping, all the cavities were restored with 4‐META/MMA‐TBB resin and pulpal responses were evaluated at days 1, 7, and 28. Kruskal–Wallis followed by Mann–Whitney U‐test was performed with a significance level of 0.05. Immunohistochemical expression of IL‐6, Nestin, and DMP‐1 was observed.At day 1, CHPPL‐1, N‐MTA, and Dycal exhibited no to mild inflammation, whilst CHPPL‐3, CHPPL‐5, and NC showed mild to moderate inflammation, and the results were significantly different (p < .05). At day 7, mild to moderate inflammation was observed in CHPPL‐1, N‐MTA, and Dycal, whereas CHPPL‐3, CHPPL‐5, and NC exhibited moderate to severe inflammation. Significant differences were observed between CHPPL‐1 and N‐MTA with NC (p < .05), CHPPL‐1 and CHPPL‐3 with CHPPL‐5 and Dycal (p < .05), and CHPPL‐3 with N‐MTA (p < .05). A thin layer of mineralized tissue formation (MTF) was observed in all groups. At day 28, CHPPL‐1, Dycal, and N‐MTA showed no to mild inflammation, whilst CHPPL‐3, CHPPL‐5, and NC exhibited mild to severe inflammation, and statistically significant difference was detected (p < .05). CHPPL‐1, Dycal, and N‐MTA exhibited continuous MTF, whilst CHPPL‐3, CHPPL‐5, and NC had thicker and interrupted MTF. Significant differences were observed between CHPPL‐1, CHPPL‐3, and N‐MTA with NC group (p < .05). Variable expressions of IL‐6, Nestin, and DMP‐1 indicated differences in the materials' impact on odontoblast‐like cell formation and tissue mineralization.These findings suggest that CHPPL‐1 has the potential to minimize pulpal inflammation and promote MTF and had similar efficacy as MTA cement. [ABSTRACT FROM AUTHOR]