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ABSTRACT: The aim of the study was to evaluate the effects of a highly potent bisphosphonate, zoledronic acid (ZOL), on cultured odontoblast-like cells MDPC-23. The cells (1.5×10(4)cells/cm(2)) were seeded for 48h in wells of 24-well dished. Then, the plain culture medium (DMEM) was replaced by fresh medium without fetal bovine serum. After 24h, ZOL (1 or 5μM) was added to the medium and maintained in contact with the cells for 24h. After this period, the succinic dehydrogenase (SDH) enzyme production (cell viability - MTT assay), total protein (TP) production, alkaline phosphatase (ALP) activity, and gene expression (qPCR) of collagen type I (Col-I) and ALP were evaluated. Cell morphology was assessed by SEM. Five μM ZOL caused a significant decrease in SDH production. Both ZOL concentrations caused a dose-dependent significant decrease in TP production and ALP activity. ZOL also produced discret morphological alterations in the MDPC-23 cells. Regarding gene expression, 1μM ZOL caused a significant increase in Col-I expression. Although 5μM ZOL did not affect Col-I expression, it caused a significant alteration in ALP expression (ANOVA and Tukey's test, p<0.05). ZOL presented a dose-dependent cytotoxic effect on the odontoblast-like cells, suggesting that under clinical conditions the release of this drug from dentin could cause damage to the pulpo-dentin complex.
Archives of oral biology 10/2012; · 1.65 Impact Factor
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ABSTRACT: The aim of this study was to evaluate the metabolism of odontoblast-like MDPC-23 cells subjected to direct LLL irradiation. The cells were seeded (20,000 cells/well) in 24-well plates and incubated for 24 hours at 37°C. After this period, the culture medium (DMEM) was replaced by fresh DMEM supplemented with 2 or 5% (stress induction by nutritional deficit) or 10% fetal bovine serum (FBS). The cells were exposed to laser doses of 2, 4, 10, 15 and 25 J/cm2 from a near infrared InGaAsP diode laser prototype (LASERTable; 780±3 nm, 40 mW). One control group (sham irradiation) was established for each experimental condition (laser dose x FBS supplementation). Three and 72 hours after the last irradiation, cells were analyzed with respect to metabolism, morphology, total protein expression and alkaline phosphatase (ALP) activity. Higher metabolism and total protein expression were observed 72 hours after the last irradiation at the doses of 15 and 25 J/cm2 (Mann-Whitney; p<0.05). Higher ALP activity was obtained with 5% FBS when the cells were irradiated with doses of 2 and 10 J/cm2. For the dose of 25 J/cm2, the highest ALP activity was observed with 10% FBS. It was concluded that the LLLT parameters used in this study stimulated the metabolic activity of the MDPC-23 cells, especially at the doses of 15 and 25 J/cm2. (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
Laser Physics Letters 01/2011; 8(2):155 - 163. · 9.97 Impact Factor
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ABSTRACT: The aim of this study was to evaluate the metabolism of odontoblast-like MDPC-23 cells subjected to di-rect LLL irradiation. The cells were seeded (20,000 cells/well) in 24-well plates and incubated for 24 hours at 37 • C. After this period, the culture medium (DMEM) was replaced by fresh DMEM supplemented with 2 or 5% (stress induction by nu-tritional deficit) or 10% fetal bovine serum (FBS). The cells were exposed to laser doses of 2, 4, 10, 15 and 25 J/cm 2 from a near infrared InGaAsP diode laser prototype (LASERTable; 780±3 nm, 40 mW). One control group (sham irradiation) was established for each experimental condition (laser dose x FBS supplementation). Three and 72 hours after the last irradiation, cells were analyzed with respect to metabolism, morphology, total protein expression and alkaline phosphatase (ALP) activ-ity. Higher metabolism and total protein expression were ob-served 72 hours after the last irradiation at the doses of 15 and 25 J/cm 2 (Mann-Whitney; p<0.05). Higher ALP activ-ity was obtained with 5% FBS when the cells were irradiated with doses of 2 and 10 J/cm 2 . For the dose of 25 J/cm 2 , the highest ALP activity was observed with 10% FBS. It was con-cluded that the LLLT parameters used in this study stimulated the metabolic activity of the MDPC-23 cells, especially at the doses of 15 and 25 J/cm 2 . (a) 10 μm ×1000 20 kV (b) (c) (d) 10 μm ×1000 20 kV 10 μm ×1000 20 kV 10 μm ×1000 20 kV Panel of SEM micrographs representative of cell morphology in each group
Laser Physics Letters 01/2011; 8(2):155--163. · 9.97 Impact Factor
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ABSTRACT: AIM: To evaluate the transenamel and transdentinal cytotoxicity of bleaching gels based on carbamide peroxide (CP) on odontoblast-like cells after different contact times of the products with enamel. Methodology: Enamel/dentine discs were obtained from bovine incisors and placed in artificial pulp chambers. Bleaching gels containing 10% or 16% CP were applied for 8 h day(-1) on the enamel side of the discs during periods of 1, 7 or 14 days. Deionized water and artificial saliva served as controls. The extracts (culture medium plus bleaching gel products that diffused through the discs) were collected and applied on previously cultured MDPC-23 cells for 1 h. Cell metabolism was evaluated by the MTT assay, and the data were analysed statistically by one-way anova and Tukey's test (α=0.05). Cell morphology was analysed by SEM. RESULTS: There was no significant difference (P>0.05) between the controls and the groups bleached with 10% CP gel. In the groups bleached with 16% CP gel, however, cell metabolism decreased significantly (P<0.05) by 40.32%, 30.16% and 26.61% at 1, 7 and 14 days, respectively. There was no significant difference (P>0.05) between 1, 7 or 14 applications of the gels for either of the CP concentrations. Conclusion: Regardless of the number of applications on an enamel surface, the 10% CP bleaching gel did not cause transenamel and transdentinal cytotoxicity to the MDPC-23 cell cultures. However, diffusion of products from the 16% CP gel through enamel and dentine and cytopathic effects to the pulp cells occurred even after a single application of this product on enamel.
International Endodontic Journal 11/2010; 44(2):116-25. · 2.18 Impact Factor
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ABSTRACT: In spite of knowing that cells under stress are biostimulated by low level laser (LLL) irradiation, the ideal condition of stress to different cell lines has not yet been established. Consequently, the aim of the present in vitro study was to evaluate the effects of a defined parameter of LLL irradiation applied on stressed odontoblast-like pulp cells (MDPC-23). The cells were seeded (12500 cells/cm2) in wells of 24-well plates using complete culture medium (DMEM) and incubated for 24 hours. Then, the DMEM was replaced by a new medium with low concentrations (nutritional stress condition) of fetal bovine serum (FBS) giving rise to the following experimental groups: G1: 2% FBS; G2: 5% FBS; and G3: 10% FBS. The cells were irradiated three times with LLL in specific parameters (808 ± 3 nm, 100 mW, 1.5 J/cm2) every 24 hours. No irradiation was carried out in groups G4 (2% FBS-Control), G5 (5% FBS-Control), and G6 (10% FBS-Control). For all groups, the cell metabolism (MTT assay) and morphology (SEM) was evaluated. The experimental groups showed enhanced cell metabolism and normal cell morphology regardless of FBS concentration. A slight increase in the cell metabolism was observed only in group G2. It was concluded that cell nutritional stress caused by reducing the concentration of FBS to 5% is the most suitable method to assess the biostimulation of LLL irradiated MDPC-23 cells. (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
Laser Physics Letters 01/2010; 7(3):247 - 251. · 9.97 Impact Factor
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ABSTRACT: Studies have shown that the increase of cell metabolism depends on the low level laser therapy (LLLT) parameters used to irradiate the cells. However, the optimal laser dose to up�regulate pulp cell activity remains unknown. Consequently, the aim of this study was to evaluate the metabolic response of odontoblast like cells (MDPC�23) exposed to different LLLT doses. Cells at 20000 cells/cm2 were seeded in 24 �well plates using plain culture medium (DMEM) and were incubated in a humidified incubator with 5% CO2 at 37°C. After 24 h, the culture medium was replaced by fresh DMEM supplemented with 5% (stress by nutritional deficit) or 10% fetal bovine serum (FBS). The cells were exposed to different laser doses from a near infrared diode laser prototype designed to provide a uniform irradiation of the wells. The experimental groups were: G1: 1.5 J/cm2 + 5% FBS; G2: 1.5 J/cm2 + 10% FBS; G3: 5 J/cm2 + 5% FBS; G4: 5 J/cm2 + 10% FBS; G5: 19 J/cm2 + 5% FBS; G6: 19 J/cm2 + 10% FBS. LLLT was performed in 3 consecutive irradiation cycles with a 24�hour interval. Non�irradiated cells cultured in DMEM supplemented with either 5 or 10% FBS served as control groups. The analysis of the metabolic response was performed by the MTT assay 3 h after the last irradiation. G1 presented an increase in SDH enzyme activity and differed significantly (Mann�Whitney test, p < 0.05) from the other groups. Analysis by scanning electron microscopy showed normal cell morphology in all groups. Under the tested conditions, LLLT stimulated the metabolic activity of MDPC�23 cultured in DMEM supplemented with 5% FBS and exposed to a laser dose of 1.5 J/cm2. These findings are relevant for further studies on the action of near infrared lasers on cells with odontoblast phenotype.
Laser Physics 01/2010; 20(7):1659--1666. · 3.61 Impact Factor
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ABSTRACT: Congenital epulis (CE) of the newborn is a rare benign soft tissue tumor that presents at birth. It occurs usually as a single mass with various sizes, although some multiple lesions have also been reported. The lesion is more common in female neonates and normally affects the maxillary alveolar ridge. Rare recurrence and no malignant alteration have also been reported. This condition may interfere with respiration, feeding or adequate closure of the mouth. A decisive diagnosis is made by histopathologic analysis as other newborn lesions can be incorrectly diagnosed as CE. This article presents a case report of a female infant who presented a fibrotic mass in the primary lateral incisor and canine region of the maxillary alveolar ridge. The lesion was not causing feeding or respiratory problems. After a watchful waiting procedure and no spontaneous regression, the lesion was excised under local anesthesia and confirmed by histopathologic analysis as CE.
Journal of the Indian Society of Pedodontics and Preventive Dentistry. 01/2010;
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ABSTRACT: In spite of knowing that cells under stress are biostim-ulated by low level laser (LLL) irradiation, the ideal condition of stress to different cell lines has not yet been established. Con-sequently, the aim of the present in vitro study was to evaluate the effects of a defined parameter of LLL irradiation applied on stressed odontoblast-like pulp cells (MDPC-23). The cells were seeded (12500 cells/cm 2) in wells of 24-well plates using com-plete culture medium (DMEM) and incubated for 24 hours. Then, the DMEM was replaced by a new medium with low concentra-tions (nutritional stress condition) of fetal bovine serum (FBS) giving rise to the following experimental groups: G1: 2% FBS; G2: 5% FBS; and G3: 10% FBS. The cells were irradiated three times with LLL in specific parameters (808±3 nm, 100 mW, 1.5 J/cm 2) every 24 hours. No irradiation was carried out in groups G4 (2% FBS-Control), G5 (5% FBS-Control), and G6 (10% FBS-Control). For all groups, the cell metabolism (MTT assay) and morphology (SEM) was evaluated. The experimental groups showed enhanced cell metabolism and normal cell mor-phology regardless of FBS concentration. A slight increase in the cell metabolism was observed only in group G2. It was concluded that cell nutritional stress caused by reducing the concentration of FBS to 5% is the most suitable method to assess the biostimu-lation of LLL irradiated MDPC-23 cells. MDPC-23 cells adhered to the glass substrate exhibited a spindle-shaped morphology and some mitosis were observed (ar-rows); SEM ×500
Laser Physics Letters 01/2010; 7:247--251. · 9.97 Impact Factor
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ABSTRACT: To evaluate the trans-enamel and trans-dentinal cytotoxic effects of a 35% H(2)O(2) bleaching gel on an odontoblast-like cell lines (MDPC-23) after consecutive applications.
Fifteen enamel/dentine discs were obtained from bovine central incisor teeth and placed individually in artificial pulp chambers. Three groups (n = 5 discs) were formed according to the following enamel treatments: G1: 35% H(2)O(2) bleaching gel (15 min); G2: 35% H(2)O(2) bleaching gel (15 min) + halogen light (20 s); G3: control (no treatment). After repeating the treatments three consecutive times, the extracts (culture medium + gel components that had diffused through enamel/dentine discs) in contact with the dentine were collected and applied to previously cultured MDPC-23 cells (50 000 cells cm(-2)) for 24 h. Cell metabolism was evaluated by the MTT assay and data were analysed statistically (alpha = 5%; Kruskal-Wallis and Mann-Whitney U-test). Cell morphology was analysed by scanning electron microscopy.
Cell metabolism decreased by 92.03% and 82.47% in G1 and G2 respectively. G1 and G2 differed significantly (P < 0.05) from G3. Regardless of halogen light activation, the application of the bleaching gel on the cultured odontoblast-like cells caused significantly more severe cytotoxic effects than those observed in the nontreated control group. In addition, significant morphological cell alterations were observed in G1 and G2.
After three consecutive applications of a 35% H(2)O(2) bleaching agent, the diffusion of the gel components through enamel and dentine caused severe toxic effects to cultured pulp cells.
International Endodontic Journal 07/2009; 42(6):516-24. · 2.18 Impact Factor
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ABSTRACT: The purpose of this study was to comparatively evaluate the response of human pulps after cavity preparation with different
devices. Deep class I cavities were prepared in sound mandibular premolars using either a high-speed air-turbine handpiece
(Group 1) or an Er:YAG laser (Group 2). Following total acid etching and the application of an adhesive system, all cavities
were restored with composite resin. Fifteen days after the clinical procedure, the teeth were extracted and processed for
analysis under optical microscopy. In Group 1 in which the average for the remaining dentin thickness (RDT) between the cavity
floor and the coronal pulp was 909.5 μm, a discrete inflammatory response occurred in only one specimen with an RDT of 214
μm. However, tissue disorganization occurred in most specimens. In Group 2 (average RDT = 935.2 μm), the discrete inflammatory
pulp response was observed in only one specimen (average RDT = 413 μm). It may be concluded that the high-speed air-turbine
handpiece caused greater structural alterations in the pulp, although without inducing inflammatory processes.
Laser Physics 11/2008; 18(12):1562-1569. · 3.61 Impact Factor
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ABSTRACT: Low-level laser therapy (LLLT), also referred to as therapeutic laser, has been recommended for a wide array of clinical procedures, among which the treatment of dentinal hypersensitivity. However, the mechanism that guides this process remains unknown. Therefore, the objective of this study was to evaluate in vitro the effects of LLL irradiation on cell metabolism (MTT assay), alkaline phosphatase (ALP) expression and total protein synthesis. The expression of genes that encode for collagen type-1 (Col-1) and fibronectin (FN) was analyzed by RT-PCR. For such purposes, odontoblast-like cell line (MDPC-23) was previously cultured in Petri dishes (15000 cells/cm2) and submitted to stress conditions during 12 h. Thereafter, 6 applications with a monochromatic near infrared radiation (GaAlAs) set at predetermined parameters were performed at 12-h intervals. Nonirradiated cells served as a control group. Neither the MTT values nor the total protein levels of the irradiated group differed significantly from those of the control group (Mann-Whitney test; p > 0.05). On the other hand, the irradiated cells showed a decrease in ALP activity (Mann-Whitney test; p < 0.05). RT-PCR results demonstrated a trend to a specific reduction in gene expression after cell irradiation, though not significant statistically (Mann-Whitney test; p > 0.05). It may be concluded that, under the tested conditions, the LLLT parameters used in the present study did not influence cell metabolism, but reduced slightly the expression of some specific proteins. (© 2008 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
Laser Physics Letters 08/2008; 5(9):680 - 685. · 9.97 Impact Factor
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M R O Carrilho,
S Geraldeli,
F Tay,
M F de Goes,
R M Carvalho,
L Tjäderhane,
A F Reis, J Hebling,
A Mazzoni,
L Breschi,
D Pashley
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ABSTRACT: Host-derived proteases have been reported to degrade the collagen matrix of incompletely-resin-infiltrated dentin. This study tested the hypothesis that interfacial degradation of resin-dentin bonds may be prevented or delayed by the application of chlorhexidine (CHX), a matrix metalloproteinase inhibitor, to dentin after phosphoric acid-etching. Contralateral pairs of resin-bonded Class I restorations in non-carious third molars were kept under intra-oral function for 14 months. Preservation of resin-dentin bonds was assessed by microtensile bond strength tests and TEM examination. In vivo bond strength remained stable in the CHX-treated specimens, while bond strength decreased significantly in control teeth. Resin-infiltrated dentin in CHX-treated specimens exhibited normal structural integrity of the collagen network. Conversely, progressive disintegration of the fibrillar network was identified in control specimens. Auto-degradation of collagen matrices can occur in resin-infiltrated dentin, but may be prevented by the application of a synthetic protease inhibitor, such as chlorhexidine.
Journal of Dental Research 07/2007; 86(6):529-33. · 3.49 Impact Factor
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ABSTRACT: Mucocele is a lesion that involves the salivary glands and respective current ducts caused mainly by traumas in the affected area. Two different histological forms can be found: extravasation phenomenon and mucus-retention cyst where the former is the most frequently observed involving minor salivary glands such as the glands present in the anterior portion of the ventral surface of the tongue (glands of Blandin-Nuhn).
This report describes a large lesion involving the ventral surface of the tongue that was definitively diagnosed by histological examination as extravasation mucocele.
Important concepts are reviewed to help clinicians correctly diagnose and treat this pathology.
International Journal of Paediatric Dentistry 12/2006; 16(6):435-9. · 1.01 Impact Factor
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ABSTRACT: The aim of this in vivo study was to evaluate the biocompatibility of three current bonding agents and calcium hydroxide cement. Sixty polyethylene tubes filled with the following materials: Group 1: Prime & Bond NT (PB-Dentsply, US; Group 2: Bond 1 (BO-Jeneric/Pentron, US); Group 3: Optibond Solo (OP-Kerr, US); and Group 4 (control): calcium hydroxide cement - Dycal (CH-Dentsply, US) were implanted into the connective tissue of 30 rats. After 15, 30 and 60 days, the implants were excised and the animals sacrificed. The biopsies were immersed in Karnovsky (pH, 7.2) fixative solution for 48 hours, and processed using routine histological technique. Six-micron-thick sections were cut and stained with hematoxilin and eosin and Masson's trichome technique. Microscopic evaluation was used to compare the connective tissue reactions caused by the experimental and control materials adjacent to the tube opening. At 15 days, the experimental and control materials triggered a moderate to intense inflammatory response which gave rise to a thick capsule adjacent to the tube opening. With time, the inflammatory reaction decreased. At 60 days, the connective tissue adjacent to the bonding agents exhibited a persistent inflammatory response mediated by macrophages and giant cells which were engulfing displaced resin components. On the other hand, for the control group (calcium hydroxide) no inflammatory response associated with a thin capsule adjacent to the material was observed even at the 30-day period. The hard-setting calcium hydroxide cement allowed complete healing and was considered more biocompatible than the bonding agents.
Journal of Oral Rehabilitation 07/2006; 33(7):542-50. · 1.53 Impact Factor
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ABSTRACT: The aim of this in vivo study was to evaluate the response of the pulp-dentin complex following application of resin-modified glass-ionomer cement, calcium hydroxide hard-setting cement and EDTA-soluble preparation of dentine matrix proteins (ESDP) in deep cavities prepared in non-human primate teeth.
Eighteen deep Class V buccal cavities were prepared in premolars of four capuccin monkeys. In Groups 1 and 2, the cavity floor was lined with ESDP or a resin-modified glass-ionomer cement (Vitrebond - 3M ESPE), respectively. In Group 3 (control), the cavity was lined with a hard setting calcium hydroxide cement (Dycal - Dentsply). The cavities were subsequently filled with amalgam. After 6 months, the animals were sacrificed and the teeth were prepared for microscopic assessment. Six-micron thick serial sections were stained with H/E, Masson's trichrome and Brown & Brenn techniques.
No inflammatory pulpal response was observed for all experimental and control Groups. However, the amount of reactionary dentin deposition differed between groups in the rank order ESDP (Group 1) > calcium hydroxide (Group 3) > resin-modified glass-ionomer (Group 2). These differences were statistically significant.
All materials were biocompatible when applied in deep cavities. ESDP stimulated higher deposition of reactionary dentin matrix than Vitrebond and Dycal.
Journal of Oral Rehabilitation 06/2006; 33(6):452-61. · 1.53 Impact Factor
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ABSTRACT: The recent paradigm that endogenous collagenolytic and gelatinolytic activities derived from acid-etched dentin result in degradation of hybrid layers requires in vivo validation. This study tested the null hypothesis that there is no difference between the degradation of dentin bonded with an etch-and-rinse adhesive and that in conjunction with chlorhexidine, an MMP inhibitor, applied after phosphoric-acid-etching. Contralateral pairs of bonded Class I restorations in primary molars of clinical subjects were retrieved after a six-month period of intra-oral functioning and processed for transmission electron microscopy. Hybrid layers from the chlorhexidine-treated teeth exhibited normal structural integrity of the collagen network. Conversely, abnormal hybrid layers were seen in the control teeth, with progressive disintegration of the fibrillar network, to the extent that it was beyond detection by collagen staining. Self-destruction of collagen matrices occurs rapidly in resin-infiltrated dentin in vivo and may be arrested with the use of chlorhexidine as an MMP inhibitor.
Journal of Dental Research 09/2005; 84(8):741-6. · 3.49 Impact Factor
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ABSTRACT: To evaluate and compare the response of pulps of rats capped with resin-modified glass-ionomer cement (RMGIC) or self-etching adhesive system.
Class I cavities were prepared on the occlusal surface of 54 maxillary first molars of 27 rats. Pulp exposure was performed on the cavity floor. The following resin-based materials were applied as pulp-capping agents: G1, Clearfil Liner Bond 2V (CLB 2V; Kuraray Co., Japan); G2, Vitrebond (VIT; 3M/ESPE, USA). In group 3 (control group), a calcium hydroxide/saline paste (CH; Labsynth, Brazil) was used. The cavities were restored with amalgam. After 7, 30 and 60 days, the animals were sacrificed and the jaws were processed for microscopic evaluation.
Despite the inflammatory response caused by the experimental and the control materials at 7 days, pulpal healing associated with calcified barrier formation was observed at 60 days following the pulp therapy. Both resin-based materials promoted a large zone of cell-rich fibrodentine matrix deposition on the pulp horn related to the pulp exposure site, which was larger to VIT than to CLB 2V specimens. Tertiary dentine underneath the fibrodentine matrix was deposited by a layer of elongated pulpal cells. The remaining pulpal tissue exhibited normal histological characteristics. In the control group, healing and dentine-bridge formation was observed at 30 days. Pulpal breakdown occurred only when bacterial infection occurred.
Both experimental pulp-capping agents allowed pulpal healing characterized by cell-rich fibrodentine and tertiary dentine deposition as well as calcified barrier formation.
International Endodontic Journal 01/2004; 36(12):831-9. · 2.18 Impact Factor
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ABSTRACT: Recent in vitro work and a short clinical study suggest that adding a bonding agent layer between sealant and saliva-contaminated enamel allows for adequate bond strength and retention of resin sealants and may improve success of all sealant applications. This five-year clinical study scored 617 occlusal and 441 buccal/lingual molar sealants, with use of a split-mouth design, with half receiving sealant alone and half bonding agent plus sealant. Treatment effects and potential risk factors for sealant failure were tested by means of a Cox regression model. Three bonding agent groups were analyzed for treatment effect: Tenure primer, Scotchbond Multi-Purpose, and 3 single-bottle dentin bonding agents as a third group. The single-bottle group was successful in reducing risk of sealant failure, with a hazard ratio (HR) of 0.53 (p = 0.014) for occlusal and 0.35 (p = 0.006) for buccal/lingual sealants. Scotchbond was detrimental to occlusal sealant success, with a HR of 2.96 (p = 0.0003). Tenure primer was neutral, showing HRs close to 1.0. Variables that affected success differed between occlusal and buccal/lingual sealants, suggesting that failures on these two surfaces may be dependent upon differing factors. Early eruption stage was a significant risk factor for both surfaces (HR = 2.91, p = 0.00001, occlusal; and HR = 1.52, p = 0.015, buccal/lingual). Behavior (HR = 1.96, p = 0.0007), salivary problems (HR = 1.73, p = 0.002), and visually apparent variations in enamel (HR = 1.51, p = 0.018) were significant risk factors for occlusal sealants only. In addition to completing detailed analyses of risk factors for sealant survival, this study shows that single-bottle bonding agents protect sealant survival, yielding half the usual risk of failure for occlusal sealants and one-third the risk of failure for buccal/lingual sealants.
Journal of Dental Research 12/2000; 79(11):1850-6. · 3.49 Impact Factor
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ABSTRACT: The purpose of the study was to evaluate the biocompatibility of two current adhesive resins and a calcium hydroxide cement. Fifty-four polyethylene tubes were filled with these dental materials, which were hand-mixed or light-cured according to the manufacturer's directions: group 1--Clearfill Liner Bond 2 (Kuraray); group 2--Single Bond (3 M); and group 3--calcium hydroxide cement (Dycal-Dentsply). The materials were implanted into dorsal connective tissue of rats, which were killed 7, 30, and 60 days after the implantation procedure. The implant sites were excised, immersed in buffered Karnovsky's fixative, and processed using routine histological techniques. Sections of 6 microns thickness were stained with hematoxylin and eosin and assessed under light microscopy. Both adhesive resins at 7 days elicited a moderate/intense inflammatory reaction that decreased over time. Fibrous capsules surrounding the tubes were observed at 30 days. Half of the samples in groups 1 and 2 showed thin fibrous capsule formation containing macrophages, capillaries, lymphocytes, fibroblasts, and collagen fibers. Connective tissue healing was observed even though many specimens exhibited a persistent inflammatory reaction mediated by macrophages and giant cells at the 60-day evaluation. Dycal allowed complete healing at 30 days with only a thin fibrous capsule. In conclusion, all experimental materials were successfully walled off by the connective tissue of the rat. However the adhesive resins may release particulates that may, in turn, induce a persistent local inflammatory reaction. Consequently, in this specific condition, these materials cannot be regarded as biocompatible. Dycal was less irritating than the adhesive resins and was better tolerated by the connective tissue.
Journal of Endodontics 10/2000; 26(9):512-6. · 2.88 Impact Factor
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ABSTRACT: To evaluate the influence of three different adhesives, each used as an intermediary layer, on microleakage of sealants applied under condition of salivary contamination.
Six different experimental conditions were compared, 3 with adhesives and 3 without. After prophylaxis and acid etching of enamel, salivary contamination was placed for 10 s. In Group SC the sealant was applied after saliva without bonding agent and then light-cured. In Group SCA, after saliva, the surface was air dried, and then the sealant was applied and cured. In Groups ScB, SB and PB, a bonding agent (Scotchbond Dual Cure/3M, Single Bond/3M and Prime & Bond 2.1/Dentsply, respectively) was applied after the saliva and prior to the sealant application and curing. After storage in distilled water at 37 degrees C for 24 hrs, the teeth were submitted to 500 thermal cycles (5 degrees C and 55 degrees C), and silver nitrate was used as a leakage tracer. Leakage data were collected on cross sections as percentage of total enamel-sealant interface length. Representative samples were evaluated under SEM.
Sealants placed on contaminated enamel with no bonding agent showed extensive microleakage (94.27% in SC; 42.65% in SCA). The SEM revealed gaps as wide as 20 microm in areas where silver nitrate leakage could be visualized. In contrast, all bonding agent groups showed leakage less than 6.9%. Placement of sealant with a dentin-bonding agent on contaminated enamel significantly reduced microleakage (P < 0.0001). The use of a bonding agent as an intermediary layer between enamel and sealant significantly reduced saliva's effect on sealant microleakage.
American journal of dentistry 09/2000; 13(4):187-91. · 0.76 Impact Factor
