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Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Objectives: To evaluate the incorporation of repairing capsules containing different monomers and polymerization modulators on the self-healing efficiency of an experimental photopolymerizable resin-based composite., Methods: Self-healing capsules containing different monomers and polymerization modulators were prepared by emulsion polymerization: TC DHEPT (TEGDMA and DHEPT), BTC DHEPT (Bis-GMA, TEGDMA, and DHEPT), and BTC BPO (Bis-GMA, TEGDMA, and BPO). The capsules were analyzed through Fourier transform infrared spectroscopy and scanning electron microscopy. The capsules were added into experimental photopolymerizable resin composites establishing the following groups: ER (Control without capsules), ER+BPO, ER+BPO+TC DHEPT , and ER+BTC BPO +BTC DHEPT . Filtek Z350 resin composite (3 M ESPE) was used as a commercial reference. The materials were tested for degree of conversion (DC), flexural strength (σf), elastic modulus (Ef), fracture toughness (virgin K IC ), self-healing efficiency (healed K IC ), and roughness. For statistical analysis, the significance value was established at an a = 0.05 level., Results: When compared to the control material, the incorporation of repairing capsules did not affect DC, σf, and Ef. Fracture toughness was statistically similar between the experimental groups (p ≤ 0.05). Healed K IC was statistically different between the groups ER+TC DHEP and ER+BTC BPO +BTC DHEPT ; the self-healing efficiency was higher for ER+TC DHEPT . Surface roughness was statistically similar among all groups., Conclusions: The use of self-healing capsules promoted repair of the material. Studies with material aging after the self-healing process are necessary to better demonstrate the effectiveness of this system., Clinical Significance: The self-healing system seemed to be a promising technology to be used in self-repaired restorative materials, which may prevent restoration fractures., Competing Interests: Declaration of Competing Interest The authors report no conflicts of interest in this work., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Purpose: To investigate the mechanical performance and fracture reliability of new generation, bulk-fill resin composites of different viscosities., Methods: Forty sound maxillary premolars were prepared into Class I cavities comprised of 5 mm width × 5 mm length × 5 mm thickness. The teeth were randomly allocated into four groups (n = 10) according to the restorative material: Negative control - without restoration; Positive control - conventional resin composite (Opallis; FGM) was applied using increments of up to 2.0 mm-thick; Bulk-Regular - bulk-fill resin composite of regular viscosity (Opus Bulk Fill; FGM) was applied using a single increment of 5 mm-thick; and Bulk-Flow - a low-viscosity bulk-fill resin composite (Opus Bulk Fill Flow; FGM) was applied as the first increment with ∼3.5 mm-thick, followed by two final increments of Opallis (∼1.5 mm-thick). The teeth were stored at 37 °C, for 24 h, and submitted to a mechanical testing machine (DL500; EMIC) under a compressive loading. Work of fracture (W f ) was also obtained. All data were analyzed using ANOVA and Tukey (α = 5%). Reliability of restorations and probability of failure were analyzed by Weibull analysis., Results: The non-restored teeth showed the weakest behavior of the study. All the restored groups demonstrated similar mechanical properties to each other (p ≥ 0.242). The positive and negative controls failed exclusively within the cohesiveness of enamel/dentin, whereas the bulk-fill-based restorations showed a mixture of cohesive and mixed failures. The restored groups showed an overall similar reliability, although the Bulk-Regular group demonstrated greater characteristic strength than the positive control., Conclusion: The novel bulk-fill resin composites of low and regular viscosities show promising application in the restoration of Class I cavities in premolars, demonstrating similar mechanical performance and reliability as compared with restorations prepared using conventional resin composites. From the bulk-fill materials, the version with regular viscosity presented the greatest compliant behavior of the study., (Copyright © 2019. Published by Elsevier Ltd.)

Objectives: This study describes the synthesis of piperonyl methacrylate (PipM) and evaluates its effect when used as coinitiator in the photoinitiated radical polymerization of experimental adhesive resins., Methods: PipM was synthetized through an esterification reaction and characterized by FTIR and 1 H NMR spectroscopy. Adhesive resins containing camphorquinone as photoinitiator and PipM or ethyl-4-dimethyl amine benzoate (EDAB) as coinitiators were formulated. Scotchbond Multipurpose (SBMP) adhesive was used as commercial reference. All materials were analyzed for polymerization kinetics, flexural strength, elastic modulus, water sorption/solubility, shear bond strength to bovine enamel and dentin, characterization of hybrid layer by scanning electron microscopy (SEM), microbiological direct contact test, and cytotoxicity., Results: The adhesive with PipM presented higher degree of conversion and lower sorption/solubility when compared with other groups. Shear bond strength to enamel and dentin were similar for PipM and EDAB materials. The percentage of cellular viability was close to 100% and similar in the experimental groups and the commercial reference., Conclusions: PipM presented similar or superior performance to the tertiary amine used as control, representing a potential alternative coinitiator for photopolymerizable dental materials., Clinical Significance: PipM could be potentially useful in the formulations of adhesive systems with enhanced chemical properties, which could mean improvement in the longevity of composite resin restorations., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Over the past years, significant effort has been dedicated to synthesizing low-shrinking formulations, however, development of dental composites with low volumetric shrinkage continues to be challenging. The purpose of this study was to synthesize a bisphenol allylic derivate (BPhADAC) and evaluate its inclusion in the formulation of a photopolymerizable dental composite resin, as a BisGMA diluent. Experimental (BisGMA/BPhADAC) and control (BisGMA/TEGDMA) photopolymerizable composites were prepared. Double bond conversion, polymerization kinetics, volumetric shrinkage, water sorption, solubility, and flexural properties were investigated. The experimental composite showed higher degree of conversion values, less volumetric shrinkage and less water sorption than the control composite (p < 0.05). In addition, flexural strength between the materials was found to be similar. The overall properties prove that the allylic monomer BPhADAC could be potentially useful in the formulation of low-shrinking dental composite resins., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Purpose: A systematic review was conducted to determine whether there were any alternative technique or additional step strategies available to reduce and control polymerization shrinkage stress development in dental resin-based restorative materials., Data Sources: This report followed the PRISMA Statement. A total of 36 studies were included in this review. Two reviewers performed a literature search up to December 2016, without restriction of the year of publication, in seven databases: PubMed, Web of Science, Scopus, SciELO, LILACS, IBECS, and BBO., Study Selection: Only in vitro studies that evaluated polymerization shrinkage stress by direct testing were included. Pilot studies, reviews and in vitro studies that evaluated polymerization shrinkage stress by indirect methods (e.g., microleakage or cuspal deflection measurements), finite elemental analysis or mathematical models were excluded. Of the 6.113 eligible articles, 36 studies were included in the qualitative analysis, and the meta-analysis was performed with 25 studies. A global comparison was performed with random-effects models (α = 0.05). The strategies were subdivided as follows: the use of an alternative technique protocol of placing the material inside the tooth cavity; the modification of the irradiation intensity or total energy delivered to the material; the use of an alternative light-curing source; or the use of an alternative photo-activation mode. All alternative strategies showed statistically significant differences when compared with their respective controls (p < 0.05)., Conclusion: The use of alternative light-curing sources contributed more to minimizing stress development than placing the material by means of an alternative technique protocol or by modifying the irradiant intensity or total energy delivered to the material during photo-activation. Moreover, the use of an alternative photo-activation mode (intermittent light, exponential, soft-start or pulse delay modes) was shown to be an effective strategy for reducing and controlling stress development in resin-based dental materials., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Purpose: A systematic review was conducted to determine whether there were composition strategies available to reduce and control polymerization shrinkage stress development in resin-based restorative dental materials., Data Sources: This report was reported in accordance with the PRISMA Statement. Two reviewers performed a literature search up to December 2016, without restriction of the year of publication, in seven databases: PubMed, Web of Science, Scopus, SciELO, LILACS, IBECS, and BBO., Study Selection: Only laboratory studies that evaluated polymerization shrinkage stress by direct testing were included. Pilot studies, reviews and in vitro studies that evaluated polymerization shrinkage stress by indirect methods (e.g., microleakage or cuspal deflection measurements), finite elemental analysis, or theoretical and mathematical models were excluded. Of the 6113 eligible articles, 62 studies were included in the qualitative analysis, and the meta-analysis was performed with 58 studies. The composition strategy was subdivided according to the modified part of the material: filler phase, coupling agent, or resin matrix. A global comparison was performed with random-effects models (α = 0.05). The only subgroup that did not show a statistical difference between the alternative strategy and the control was 'the use of alternative photo-initiators' (p = 0.29)., Conclusion: Modification of the resin matrix made the largest contribution to minimizing stress development. The technology used for decreasing stress in the formulation of low-shrinkage and bulk-fill materials was shown to be a promising application for reducing and controlling stress development., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Introduction: This study evaluated the influence of cervical preflaring on the incidence of root dentin defects after root canal preparation., Methods: Extracted human maxillary central incisors were selected and allocated to 1 control group and 12 experimental groups (n = 15). Teeth in the control group were left unprepared, whereas the others were prepared using 2 reciprocating single-file systems (Reciproc and WaveOne [WO]), 3 full-sequence rotary systems (ProTaper Universal, ProTaper Next [PTN], and ProFile), and K-files driven by an oscillatory system, with and without cervical preflaring. Roots were then horizontally sectioned at 4, 8, and 12 mm from the apex, stained with 1% methylene blue, and viewed through a stereomicroscope at ×25 magnification. Slices were inspected and the absence/presence of defects (fractures, partial cracks, and craze lines) recorded. Data were analyzed using Kolmogorov-Smirnov and Levene tests followed by the Tukey post hoc test at a significance level of P < .05., Results: No root dentin defects were observed in the control group. WO was associated with a significantly higher number of defects than K-files, ProFile, and PTN (P < .05), but was not significantly different from Reciproc or ProTaper Universal (P > .05). Cervical preflaring significantly reduced the incidence of fractures and other defects in the WO and PTN groups (P < .05)., Conclusions: All instruments caused root dentin defects, regardless of the enlargement or not of the cervical portion. Cervical preflaring was associated with a lower incidence of defects, mainly in root canals prepared with WO and PTN., (Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

This study evaluated the anti-antibiofilm potential of silver methacrylate (Ag) or di-n-butyldimethacrylatetin (Sn) in experimental adhesive systems. Ag and Sn methacrylates were incorporated at 0.5mol%, 1mol% and 2mol% in an adhesive resin. The anti-antibiofilm potential, degree of conversion (DC), microtensile bond strength (μTBS), water sorption/solubility (W SR/SL ), bonded interfaces pattern (SEM), cytotoxicity and leaching of Ag and Sn ions were evaluated. Data were statistically analyzed considering α = 0.05. Only Ag at 2% affected DC and μTBS. Ag at 1% and 2% and Sn at 1% and 2% showed anti-biofilm potential against Mutans streptococci. Ag at 1% and 2% and Sn at 2% showed a statistically significant difference to the control in W SR/SL (p < 0.05). The additions of metal methacrylate did not affect cell viability, being the adhesive resins statistically similar to controls. Leached metals of Ag were more than 100x higher than for Sn. Between the concentration tested, Ag and Sn methacrylate at 1% presented an anti-biofilm effect without altering the mechanical properties evaluated., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Introduction: The aim of this study was to evaluate the physical properties, the antimicrobial effect, and the biocompatibility of dual polymerization experimental sealers after the incorporation of dibutyltin (ET) or calcium (EC) methacrylate at concentrations of 0.5%, 1%, 2%, and 5%., Methods: RealSeal (RS; SybronEndo, Glendora, CA) was used as a commercial control. Materials were evaluated regarding film thickness, degree of conversion, radiopacity, antimicrobial effect against Enterococcus faecalis using the modified direct contact test, and cell viability. Data were analyzed using analysis of variance followed by the Tukey test or the Student-Newman-Keuls test in SigmaPlot 12.0 (Systat Software, Inc, Point Richmond, CA) (P = .05)., Results: The film thickness of the dibutyltin and calcium were greater than experimental sealers following the standards given by ISO 6876:2012. For degree of conversion, dual polymerization was not influenced by the addition of metal methacrylate. Regarding the modified direct contact test, calcium and dibutyltin at all concentrations showed antimicrobial activity when compared with the positive control after 48 hours of contact (P < .05). In cell viability, ET at all concentrations showed high cytotoxicity similar to RS, and EC at concentrations of 0.5%, 1%, and 2% showed moderate cytotoxicity that was less than 5% of calcium and RS., Conclusions: It was concluded that calcium and dibutyltin methacrylate incorporation in experimental sealers promoted the antimicrobial effect. The incorporation of calcium methacrylate at 0.5%, 1%, and 2% seemed to be a good treatment option to provide antimicrobial activity associated with moderate cytotoxicity and adequate physical properties., (Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Dental pulp-derived stem cells (DPSCs) have the potential to regenerate dentin and dental pulp tissue because of their differentiation capacity and angiogenic properties. However, for regenerative approaches to gain regulatory and clinical acceptance, protocols are needed to determine more feasible ways to cultivate DPSCs, namely, without the use of xenogeneic-derived components (animal sera) and exogenous growth factors., Methods: In this study, human DPSCs were isolated from third molars and expanded in standard culture conditions containing fetal bovine serum (DPSCs-FBS) or conditions containing human serum (DPSCs-HS). After cell characterization and evaluation of their angiogenic secretome, DPSCs were seeded in tooth slice/scaffolds and implanted subcutaneously into immunodeficient mice. After 30 days, tooth slices were retrieved and evaluated for dental pulp tissue regeneration. Immunohistochemistry and confocal microscopy were used to quantify blood vessel formation and evaluate predentin and dentin formation., Results: After culture, DPSCs-HS produced concentrations of angiogenic growth factors equivalent to DPSCs-FBS. Additionally, in DPSCs-HS, several angiogenic factors were produced in at least 1-fold higher concentrations than in DPSCs-FBS. In vivo, it was determined that DPSCs-HS produced a robust angiogenic response and regeneration of dentin equivalent to DPSCs-FBS., Conclusions: These findings show that DPSCs can be isolated and expanded to clinical scale numbers in media devoid of animal serum or exogenous growth factors and still maintain their pulp regenerative properties. The implications of these findings are significant for further development of clinical protocols using DPSCs in cell therapies., (Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: A systematic review was conducted to determine whether the etch-and-rinse or self-etching mode is the best protocol for dentin and enamel adhesion by universal adhesives., Data: This report followed the PRISMA Statement. A total of 10 articles were included in the meta-analysis., Sources: Two reviewers performed a literature search up to October 2014 in eight databases: PubMed, Web of Science, Scopus, BBO, SciELO, LILACS, IBECS and The Cochrane Library., Study Selection: In vitro studies evaluating the bond strength of universal adhesives to dentin and/or enamel by the etch-and-rinse and self-etch strategies were eligible to be selected. Statistical analyses were conducted using RevMan 5.1 (The Cochrane Collaboration, Copenhagen, Denmark). A global comparison was performed with random-effects models at a significance level of p<0.05., Results: The analysis of dentin micro-tensile bond strength showed no statistically significant difference between the etch-and-rinse and self-etch strategies for mild universal adhesives (p≥0.05). However, for the ultra-mild All-Bond Universal adhesive, the etch-and-rinse strategy was significantly different than the self-etch mode in terms of dentin micro-tensile bond strength, as well as in the global analysis of enamel micro-tensile and micro-shear bond strength (p≤0.05)., Conclusions: The enamel bond strength of universal adhesives is improved with prior phosphoric acid etching. However, this effect was not evident for dentin with the use of mild universal adhesives with the etch-and-rinse strategy., Clinical Significance: Selective enamel etching prior to the application of a mild universal adhesive is an advisable strategy for optimizing bonding., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Objectives: The aim of this study was to synthesize an alternative acidic monomer (polypropylene glycol phosphate methacrylate--Poly-P) to constitute experimental two-step self-etch adhesive systems and also to evaluate its influence on the pH and microshear bond strength (μSBS) to enamel., Methods: Primers containing Poly-P (10, 15, 30 or 50wt.%), HEMA, ethanol, and water were prepared and allocated in subgroups according to a buffered or non-buffered pH. One experimental control and one commercial (Clearfill™ SE Bond) references were used. μSBS protocol was performed at human enamel, followed by mechanical testing. Scanning electron microscopy (SEM) was performed after each primer application. Data was analysed by one-way Kruskal-Wallis and Student-Newman-Keuls tests (p<0.05) and by linear regression predictive models., Results: As greater the Poly-P content, the lower the primer's pH. Buffered groups showed lower μSBS values than non-buffered groups. Groups with Poly-P content equal or higher than 30wt.% showed similar μSBS results when compared to the controls. SEM images demonstrated that primers with high Poly-P content etched enamel with prisms exposure., Conclusions: The pH of the primer was directly influenced by the concentration of acidic monomer, which directly affected the adhesion to enamel. Both the acidity and the type of acid-functional monomer present in the adhesive influenced the bond strength results., Clinical Significance: Poly-P synthesis was easy and effective, and considering the good bond strength results obtained, this acid-functional monomer may be potentially used in the formulation of self-etch dental adhesive systems., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Introduction: In this study, the effect of different post surface treatments on the retention of glass fiber-reinforced post to root dentin was evaluated. The hypotheses tested were (1) post silanization would not improve its retention and (2) the application of silane plus resin adhesive on the post would enhance its retention., Methods: After root canal preparation, 4 different protocols (n = 5) of post surface treatment were evaluated, combined with or without silane (Silane coupling agent) and adhesive (Scotchbond Multipurpose): silane + adhesive (S/A), only silane, only adhesive, or no treatment (control). RelyX ARC was used for post cementation. Next, specimens were subjected to push-out bond strength testing, and data were analyzed by two-way analysis of variance and Tukey test (P < .05)., Results: S/A showed higher bond strength than other protocols in the middle and coronal root regions (P < .001). Only silane did not enhance post retention compared with control (P > .05). The root dentin region influenced bond strength results only in the S/A group., Conclusions: Whereas silanization as the only post surface treatment did not improve retention, the combination of silane plus resin adhesive enhanced post retention to dentin in the middle and coronal root regions., (Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Emerging understanding about interactions between stem cells, scaffolds, and morphogenic factors has accelerated translational research in the field of dental pulp tissue engineering. Dental pulp stem cells constitute a subpopulation of cells endowed with self-renewal and multipotency. Dental pulp stem cells seeded in biodegradable scaffolds and exposed to dentin-derived morphogenic factors give rise to a pulplike tissue capable of generating new dentin. Notably, dentin-derived proteins are sufficient to induce dental pulp stem cell differentiation into odontoblasts. Ongoing work is focused on developing ways of mobilizing dentin-derived proteins and disinfecting the root canal of necrotic teeth without compromising the morphogenic potential of these signaling molecules. On the other hand, dentin by itself does not appear to be capable of inducing endothelial differentiation of dental pulp stem cells despite the well-known presence of angiogenic factors in dentin. This is particularly relevant in the context of dental pulp tissue engineering in full root canals in which access to blood supply is limited to the apical foramina. To address this challenge, scientists are looking at ways to use the scaffold as a controlled-release device for angiogenic factors. The aim of this article was to present and discuss current strategies to functionalize injectable scaffolds and customize them for dental pulp tissue engineering. The long-term goal of this work is to develop stem cell-based therapies that enable the engineering of functional dental pulps capable of generating new tubular dentin in humans., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The aim of this study was to evaluate and compare several physicochemical properties including working and setting times, flow, solubility, and water absorption of a recent calcium silicate-based sealer (MTA Fillapex; Angelus, Londrina, Brazil) and an epoxy resin-based sealer (AH Plus; Dentsply, Konstanz, Germany)., Methods: The materials were handled following the manufacturer's instructions. The working time and flow were tested according to ISO 6876:2001 and the setting time according to American Society for Testing and Materials C266. For solubility and water absorption tests, the materials were placed into polyvinyl chloride molds (8 × 1.6 mm). The samples (n = 10 for each material and test) were placed in a cylindrical polystyrene-sealed container with 20 mL deionized water at 37°C. At 1, 7, 14, and 28 days, the samples were removed from the solutions and blotted dry for solubility and water absorption tests. The data were analyzed using 1-way analysis of variance with the Tukey test (P < .05)., Results: MTA Fillapex showed the lowest values of flow, working and setting times, solubility, and water absorption (P < .05). The solubility and water absorption increased significantly over time for both materials in a 1- to 28-day period (P < .05)., Conclusions: MTA Fillapex showed suitable physical properties to be used as an endodontic sealer., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate the influence of Bis-EMA 30 on the resin-to-dentin microtensile bond strength (microTBS) and structural reliability of the experimental three-step etch-and-rinse adhesive systems., Methods: Five experimental primers containing different dimethacrylate monomer concentrations (0, 10, 20, 40, 60 wt% of the Bis-EMA 30, P0.P60) added to acid monomer and solvents (ethanol/water), and a resin bond (Bis-GMA/TEGDMA, 50/50 wt%) were formulated. The adhesive system Scotchbond MultiPurpose (SBMP, 3M ESPE) was tested as commercial reference. Sixty bovine incisors were randomly separated into six groups, and their superficial coronal dentin was exposed. After acid etching and rinsing, the excess water was removed from the surface with absorbent paper. Each experimental primer was actively applied (30 s), followed by a mild air stream (10 s). The experimental adhesive resin was applied and light activated for 20 s. Resin composite restorations were incrementally built up. The restored teeth were stored in distilled water at 37 degrees C for 24 h, and then sectioned to obtain sticks with a cross-sectional area of approximately 0.5 mm(2), after which 24 specimens per group were subjected to the microTBS test. Data (MPa) were analyzed by One-way ANOVA, Tukey test (alpha=0.05) and Weibull analysis., Results: The P40 group showed microTBS means similar to those of the control (SBMP), whereas both had statistically higher values when compared with the other groups (p<0.001). Moreover, P40 showed higher structural reliability, represented by the high Weibull modulus and characteristic strength values. The lowest microTBS was observed in the P0, P10 and P20 groups, which also had low structural reliability., Significance: Bis-EMA 30 is a promising monomer to be considered as a substitute for HEMA in adhesive system compositions., (Copyright 2010 Elsevier Ltd. All rights reserved.)

This study investigated the impact of immediate and delayed light activation on self-polymerization of a model dual-cured luting agent. The material presented the following components: base paste - 2,2-bis[4-(2-hydroxy-3-methacryloxyprop-1-oxy)phenyl]propane/triethylene glycol dimethacrylate (TEGDMA), camphorquinone, dimethyl-p-toluidine, butylated hydroxytoluene (BHT), glass fillers; catalyst paste - bisphenol-A ethoxylated dimethacrylate/TEGDMA, benzoyl peroxide, BHT, fillers. The pastes were mixed and seven polymerization scenarios tested: immediate light activation using low (5Jcm(-2)) or high (20Jcm(-2)) energy dose; delayed light activation (after 2min - short delay) using low or high dose; delayed light activation (after 10min - long delay) using low or high dose; and self-polymerization only. The degree of conversion (DC) and rate of polymerization (R(p)) were evaluated for 30min by real-time infrared spectroscopy. The lowest DC was detected for the self-polymerized and immediate-low dose groups, whereas the immediate-high dose and short delay-high dose groups showed the highest values. For the self-polymerized and immediate-high dose samples, R(p)(max) was detected after approximately 7s, whereas this took approximately 14s for the immediate-low dose group. R(p)(max) for the immediate-high dose group was higher than for the self-polymerized sample, which in turn was higher than for the immediate-low dose group. R(p)(max) for the short delay groups was higher than for the long delay groups. In conclusion, the extent of self-polymerization was influenced by the light dose reaching the material, which was dependent on high radiant exposure for optimal polymerization and the moment at which the light was applied; the short delay increased the DC for lower doses, while also generally decreasing the R(p) for all scenarios.

The aim of this study was to evaluate the kinetics of conversion of Scotchbond Multi-purpose Plus (3M ESPE, St Paul, MN) and Prime&Bond NT (Dentsply De Trey, Konstanz, Germany) used in light-cured, self-cured, or dual-cured versions. The adhesive systems were used in the light-cured version (without the use of chemical initiator) or mixed with its respective chemical initiator either with light activation (dual-cured) or not (self-cured). The degree of conversion (DC) was monitored as a function of time during 5 minutes with a Fourier transform infrared spectrometer equipped with an attenuated total reflectance device. Light-cured and dual-cured modes of Scotchbond Multi-purpose Plus presented the highest DC at 5 minutes. The addition of the self-cure activator (dual-cured mode) to Prime&Bond NT reduced the DC. For the self-cured versions, only the Scotchbond Multi-purpose Plus presented any polymerization reaction at 5 minutes. For the two bonding systems tested, it appears that light curing of the adhesive is important in order to reach a high DC in the first moments after the bonding procedure.

Objectives: The aim of this study was to synthesize an acidic monomer using an alternative synthetic pathway and to evaluate the influence of the acidic monomer concentration on the microtensile bond strength to dentin., Methods: The intermediary 5-hydroxypentyl methacrylate (HPMA) was synthesized through methacrylic acid esterification with 1,5-pentanediol, catalyzed by p-toluenesulfonic acid. To displace the reaction balance, the water generated by esterification was removed by three different methods: anhydrous sodium sulfate; molecular sieves or azeotropic distillation. In the next step, a phosphorus pentoxide (4.82 mmol) slurry was formed in cold acetone and 29 mmol of HPMA was slowly added by funnel addition. After the reaction ended, solvent was evaporated and the product was characterized by 1HNMR and FTIR. The phosphate monomer was introduced in a self-etch primer at concentrations of 0, 15, 30, 50, 70 and 100 wt%. Clearfil SE Bond was used as commercial reference. Microtensile bond strength to dentin was evaluated 24h after the bonding procedures, followed by fracture analysis (n=20). Data was submitted to ANOVA and Tukey's post hoc test., Results: The highest yield was obtained (62%) when azeotropic distillation was used, while the reaction with molecular sieves was not feasible. The phosphoric moiety attachment to the monomer was successfully performed with a quantitative yield that reached around 100%. The acidic monomer concentration significantly affected the bond strength and the highest mean (55.1+/-12.8 MPa) was obtained when 50% of acidic monomer was used., Conclusion: The synthesis pathways described in the present study appear to be a viable alternative for developing phosphate monomers.

The aim of this study was to evaluate the influence of an onium salt in the polymerization kinetics of a dental adhesive model resin. A monomer mixture, based on Bis-GMA, TEGDMA and HEMA, was used as a model dental adhesive resin, which was polymerized using camphorquinone (CQ) as a photo-initiator in addition to either binary or ternary photo-initiator systems. The binary systems were formulated with different concentrations of diphenyliodonium hexafluorphosphate or ethyl 4-dimethylaminobenzoate in relation to the monomer and 1mol% of CQ. The ternary system was a blend of 1mol% of CQ, 2mol% of ethyl 4-dimethylamino benzoate and 0.25, 0.5, 1, 2 or 4mol% of onium salt. Real time Fourier Transform infrared spectroscopy was used to investigate the polymerization reaction over the photo-activation time. When CQ was used as photo-initiator, a slow polymerization reaction was observed and a lower monomer conversion. The addition of a second component (onium salt or amine) increases the polymerization rate and conversion independent on the co-initiator concentration. Ternary photo-initiator system showed an improvement on the polymerization rate of the dental adhesive model resin leading to high conversion in short photo-activation time. Also, a mechanism for initiating polymerization using an amine or onium salt as a co-initiator component is proposed.

The aim of this study was to investigate the expression of 2 extracellullar matrix glycoproteins, fibronectin (FNC) and tenascin (TNC), following direct pulp capping with calcium hydroxide (CH). Third molars scheduled for extraction were used. Standardized class I cavities with pulp exposures were prepared. After control of bleeding, CH powder was applied in the exposure sites, which were covered with CH cement (Dycal; Dentsply) and the cavities were filled with zinc oxide-eugenol cement. Three teeth were extracted at each post-treatment period (1, 7, 14, and 30 days). Demineralized and paraffin-embedded specimens were stained for histologic technique (hematoxylin-eosin) and for immunohistochemical analysis. Anti-TNC and anti-FNC monoclonal antibodies were used with the streptavidin-biotin complex method. Generally, similar patterns of immunohistochemical expression were observed for TNC and FNC in the pulp tissue as a whole. In the exposure site, TNC immunostaining increased over time, exhibiting a thicker immunostaining pattern within 30 days. The imunohistochemical technique showed expression of both glycoproteins during pulp healing process.

Objectives: The aim of this study was to investigate new dentin bonding agents formulated with 2,3-epithiopropyl methacrylate (ETMA) comonomer blends., Methods: Synthesis and characterization of ETMA were performed. Adhesive resins with three different ETMA concentrations (0.1, 1 and 10 wt.%) were prepared. To comparison a blend with only Bis-GMA/HEMA and with 1% of GMA were used as controls. FTIR analysis was used to verify the degree of conversion. Blend copolymerization was investigated by (1)H NMR spectroscopy analysis. To investigate immediate properties of experimental adhesives, microtensile bond strength to human dentin and SEM fractographic analysis were studied., Results: ETMA was synthesized with 90% yield through a one step synthetic route. Degree of conversion for the experimental and control resins was not significantly different. Different monomers showed copolymerization among them, not presenting traces of ETMA release in 0.1 and 1% groups. Bonding agents containing ETMA had statistically higher microtensile bond strength values than the no ETMA adhesive (p<0.05)., Conclusions: Dental adhesive resin-ETMA mixtures produced increased bond strengths without harming the other properties investigated.