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PubMedDate not supplied

Microleakage evaluation of a flowable polyacid-modified resin composite used as fissure sealant on air-abraded permanent teeth.

This study evaluated the microleakage of a flowable polyacid-modified resin composite used as a fissure sealant on air-abraded teeth in comparison to a resin-based fluoride sealant. Sixty extracted human third molars were divided into six subgroups (n = 10) under two main groups (fissure sealant materials). The occlusal surfaces of the teeth were air-abraded at 80 psi using 50 microm particles of aluminum oxide for 30 seconds, followed by rinsing and drying. Delton FS+ (Dentsply International) and Dyract Flow (Dentsply DeTrey) were applied to the teeth in subgroups following application of: a) an acid etching and bonding agent, b) bonding agent alone or c) air-abrasion alone, respectively. Acid etching (Delton EZ Etch, Dentsply International) and bonding agent application (Prime & Bond NT, Dentsply DeTrey) were done according to the manufacturers' instructions. The teeth were thermocycled for 500 cycles between 5 degrees C and 55 degrees C with dwell time of 15 seconds. Basic fuchsin (0.5%) staining followed by buccolingual sectioning was performed. Microleakage was evaluated at 20x optical magnification. Kruskal-Wallis test was used to make comparisons among six subgroups. Pairwise comparisons were done with the Mann-Whitney U test with the level of significance set as alpha = 0.05. Dyract Flow application as a fissure sealant on air-abraded permanent teeth in combination with acid etching and/or bonding agent provided microleakage results comparable to Delton FS+. Results also showed that the use of air abrasion, alone, resulted in significantly higher microleakage scores.

Acid Etching, Dental↗
PubMed2003

Microleakage of resin-based liner materials and condensable composites using filled and unfilled adhesives.

PURPOSE: To evaluate the efficacy of differing resin based liner materials in reducing microleakage. METHODS: 80 freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into two groups; each one was divided into four subgroups (A-B-C-D for Group 1 and E-F-G-H for Group 2). Each prepared tooth was etched with 32% H3PO4 (Uni Etch); in Group 1, one coat of One Step and in Group 2, two coats and two cures of Prime & Bond NT adhesives were applied. In each group 1 mm layer of three different liners was used: A2 Heliomolar RO for A and E; A2 Heliomolar Flow for B and F; A2 Bisfil 2B for C and G. No liner was used for D and H subgroups. Teeth were then restored using 2 mm increments of Pyramid A2 Dentin and A1 Enamel and cured with a VIP curing light. Teeth were thermocycled x500 between 5 degrees C and 55 degrees C with a dwell of 30 seconds and then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at x20 magnification. Dye penetration was scored using an Ordinal Scoring System where 0= no penetration; 1= enamel penetration; and 2= dentin penetration. RESULTS: A Chi Square Test revealed a statistically significant difference between Group 1 and Groups 2 (P < 0.001). Group 1 yielded the most microleakage. No statistically significant difference was noted between the subgroups of each group; a statistically significant difference of B and D vs. E and H (P < 0.01 > 0.001) and B vs. G and D (P < 0.05 > 0.01) was also noted. The dentin bonding agent in Group 2 contributed to a reduction of microleakage when compared to Group 1.

Acid Etching, Dental↗
PubMed2006

Diethylenetriamine-grafted poly(glycidyl methacrylate) adsorbent for effective copper ion adsorption.

Amine-functionalized adsorbents have attracted increasing interest in recent years for heavy metal removal. In this study, diethylenetriamine (DETA) was successfully grafted (through a relatively simple solution reaction) onto poly(glycidyl methacrylate) (PGMA) microgranules to obtain an adsorbent (PGMA-DETA) with a very high content of amine groups and the PGMA-DETA adsorbent was examined for copper ion removal in a series of batch adsorption experiments. It was found that the PGMA-DETA adsorbent achieved excellent adsorption performance in copper ion removal and the adsorption was most effective at pH>3 in the pH range of 1-5 examined. X-ray photoelectron spectroscopy (XPS) revealed that there were different types of amine sites on the surfaces of the PGMA-DETA adsorbent but copper ion adsorption was mainly through forming surface complexes with the neutral amine groups on the adsorbent, resulting in better adsorption performance at a higher solution pH value. The adsorption isotherm data best obeyed the Langmuir-Freundlich model and the adsorption capacity reached 1.5 mmol/g in the case of pH 5 studied. The adsorption process was fast (with adsorption equilibrium time less than 1-4 h) and closely followed the pseudo-second-order kinetic model. Desorption of copper ions from the PGMA-DETA adsorbent was most effectively achieved in a 0.1 M dilute nitric acid solution, with 80% of the desorption being completed within the first 1 min. Consecutive adsorption-desorption experiments showed that the PGMA-DETA adsorbent can be reused almost without any loss in the adsorption capacity.

Adsorption↗
PubMed2006

Compressive strength recovery by composite onlays in primary teeth. Substrate treatment and luting agent effects.

OBJECTIVES: To evaluate 1% NaOCl treatment and two resin luting agent effects on compressive strength recovery in composite onlays on primary teeth and to analyze the fractures type. METHODS: Forty sound primary molars crowns were prepared in the standard machine and randomly divided into four groups (n=10): G1 (1% NaOCl/ 30 min+EnForce); G2 (without 1% NaOCl EnForce); G3 (1% NaOCl/ 30 min+Rely X); G4 (without 1% NaOCl+Rely X). The onlays were made using Z250 composite on plaster models. Ten sound teeth were used as control group (CG). All groups were submitted to compression mechanic test in a universal test machine INSTRON at 1mm/min cross-head speed. After that, the data (kgf) were submitted to ANOVA test (alpha=0.05). Finally, the fracture types were classified in a crescent scale (1-5) related with severity degree and submitted to Fisher's Exact Test (p<0.05). Scanning electronic microscope analysis was done in order to illustrate the fractures sites. RESULTS: The values of compressive strength of experimental groups did not differ each others neither from control group (p>0.05). The results from fracture type showed that types 5 and 4 fractures (most severe) present the highest percentage to experimental groups. Conversely, the CG showed higher percentage of fracture types 2 and 3. CONCLUSIONS: This research found that the composite onlays recovered the compressive strength compared to sound teeth, regardless of the substrate treatment and cement agent used. Nevertheless, no group showed similar type of fractures to CG, which had more frequency of less severe fracture types.

Acetone↗
PubMed2001

Bonding amalgam to enamel: shear bond strength and SEM morphology.

STATEMENT OF PROBLEM: Most studies of amalgam bonding have used dentin as the substrate. There is little data on bonding to enamel. PURPOSE: This study evaluated the shear bond strength of amalgam to enamel with the use of 3 resin cements, 1 resin-modified glass ionomer lining cement, and 2 dentin bonding agents. MATERIAL AND METHODS: Sixty bovine teeth were trimmed to expose a flat enamel surface and randomly assigned to 6 test groups of 10 specimens each. A single-plane lap shear test assembly was used. The enamel surfaces were treated with either Amalgambond Plus (group I, control), 2 coats of Amalgambond Plus (group II), light-polymerized Panavia F followed by an additional coat of autopolymerized Panavia F (group III), light-polymerized Fuji Lining LC followed by an additional coat of acid-base set Fuji Lining LC (group IV), Clearfil SE Bond followed by an additional coat of autopolymerized Panavia F (group V), or Single Bond followed by an additional coat of autopolymerized RelyX ARC (group VI). Freshly mixed amalgam was condensed against the treated enamel surfaces. Shear bond strengths for each group were compared with 1-way ANOVA and post hoc Duncan's test (P=.05). Fracture modes were examined visually. SEM observations of the fractured enamel surfaces, interfacial morphology, and conditioned enamel surfaces for each group were performed. RESULTS: Low bond strengths of 1.2 and 1.6 MPa were obtained in groups VI and I, respectively. The dual application of materials in all remaining groups resulted in higher bond strengths that ranged from 14.2 to 15.7 MPa. SEM illustrations revealed various degrees of intermingling between the adhesive material and amalgam. The conditioned enamel surfaces were morphologically varied according to conditioning solution. CONCLUSION: In this in vitro study, with the exception of group VI, the dual application of either adhesive resins or resin-modified glass ionomer resulted in satisfactory bond strengths of amalgam to enamel (up to 16 MPa).

Acid Etching, Dental↗
PubMed1979

2-Hydroxy- ethyl-methacrylate and di- and tetraethylene glycol dimethacrylate: contact sensitizers in a photoprepolymer printing plate procedure.

In a platemaking procedure differing from Nyloprint and Letterflex, contact sensitizations to 2-hydroxy-ethyl-methacrylate, di- and tetraethylene glycol dimethacrylate and nicotinic acid were found. Preoperational testing of the complete mixture gave a false impression of safety. Preventive measures and enumeration of acrylic substances so far recognized as sensitizers or cross-sensitizers are discussed.

Acrylic Resins↗
PubMed2000

Microleakage of a condensable resin composite: an in vitro investigation.

OBJECTIVE: The purpose of this investigation was to evaluate microleakage in Class II cavities restored with the condensable resin composite SureFil, placed with or without a liner and 1 of 2 different dentin bonding agents. METHOD AND MATERIALS: Extracted noncarious human teeth were randomly divided into 4 groups of 15 each and restored according to manufacturer's instructions: group 1, SureFil and Prime & Bond NT; group 2, SureFil and PQ1; group 3, SureFil, PermaFlow, and PQ1; group 4, Heliomolar and Syntac Single-Component (control). Specimens were stored in 37 degrees C water for 24 hours. All specimens were thermocycled between 5 degrees C and 55 degrees C for 500 cycles. Each specimen was immersed in 0.2% basic fuchsin dye for 24 hours and then sectioned longitudinally and horizontally. Dye penetration at enamel and cementum margins were viewed at x30 magnification by 2 independent, calibrated evaluators. Specimens exhibiting dye penetration > or = 0.1 mm beyond the cavosurface margin were considered to have leakage. RESULTS: Chi-square tests revealed no statistically significant differences in the presence of microleakage when all groups were analyzed together. However, 2 by 2 comparisons revealed that group 3 had significantly fewer specimens with microleakage than did group 1, 2, or 4. CONCLUSION: To limit microleakage, a flowable composite should be used as a liner when a condensable composite material is used.

Acid Etching, Dental↗
PubMedDate not supplied

Bond strength of self-etching primers to enamel and dentin of primary teeth.

PURPOSE: The objective of this in vitro study was to evaluate the tensile bond strength of three self-etching primers to human primary enamel and dentin. METHODS: Forty (40) freshly extracted primary molars were sectioned bucco-lingually and embedded in self-curing acrylic resin with the facial or lingual surfaces exposed. The specimens were wet ground to 600 grit SiC paper to expose a flat enamel or dentin surface. The materials tested were: Prompt L-Pop (LP2, ESPE), Clearfil SE Bond (CSE, Kuraray America), Etch and Prime 3.0 (EP, Degussa) anda control, Prime and Bond NT (NT, Dentsply/Caulk). The adhesive systems were applied according to the manufacturers' instructions. An inverted, truncated cone of composite (Pertac II, ESPE) with a 2-mm bonding diameter was cured using a polytetrafluoroethylene jig. The specimens were debonded in tension using a universal testing machine (Instron) at a crosshead speed of 0.5 mm/min. RESULTS: Analysis of variance (ANOVA) showed significant differences existed between the four systems and two surfaces. To enamel of primary teeth, Prime and Bond NT had significantly higher bond strength (25.9 MPa) than when bonding with the three acidic primers Prompt L-Pop (18.5 MPa), Etch and Prime 3.0 (19.3 MPa) and Clearfil SE Bond (18.7 MPa). Complete bond failures occurred with Prompt L-Pop and Etch and Prime 3.0 to dentin of primary teeth. With a mean of 39 Mpa, the bond strength to dentin of primary teeth with Clearfil SE Bond was significantly higher than with Prime and Bond NT (12.5 MPa). CONCLUSIONS: The results of this in vitro study show that the four adhesive systems tested bonded effectively to enamel of primary teeth, but only CSE achieved adequate bond strengths to dentin of primary teeth.

Acid Etching, Dental↗
PubMedDate not supplied

Influence of different repair procedures on bond strength of adhesive filling materials to etched enamel in vitro.

Contamination of etched enamel with repair bond agents during repair of dental restorations may interfere with the bonding of composite to enamel. This study examined the bond strength of adhesive filling materials to etched bovine enamel after pre-treatment with the repair systems Monobond S, Silibond and Co-Jet. The materials Tetric Ceram, Dyract and Definite and their corresponding bonding agents (Syntac Single Comp, Prime & Bond NT, Etch and Prime) were tested in combination with the repair systems. One hundred and thirty-five enamel specimens were etched (37% phosphoric acid, 60 seconds) and equally distributed among three groups (A-C). In Group A, the repair materials were applied on etched enamel followed by applying the composite materials without using their respective bonding material. In Group B, the composite materials were placed on etched enamel after applying the repair materials and bonding agents. In control Group C, the composite materials and bonding agents were applied on etched enamel without using the repair systems. In each sub-group, every composite material was applied on 15 specimens. Samples were stored in artificial saliva for 14 days and thermocycled 1,000 times (5 degrees C/55 degrees C). The shear bond strength of the samples were then determined in a universal testing machine (ISO 10477). Applying Monobond or Silibond followed by the use of its respective bonding agents resulted in a bond strength that was not statistically different from the controls for all filling materials (Group C). The three composites that used Monobond and Silibond without applying the corresponding bonding agent resulted in bond strengths that were significantly lower than the controls. Utilizing the Co-Jet-System drastically reduced the bond strength of composites on etched enamel. Contamination of etched enamel with the repairing bonding agents Monobond and Silibond does not interfere with bond strength if the application of Monobond and Silibond is followed by using its corresponding bonding system of the composites tested.

Acid Etching, Dental↗
PubMed1999

Cytotoxic effects of current dental adhesive systems on immortalized odontoblast cell line MDPC-23.

OBJECTIVES: Evaluate the cytotoxic effect of the three dental adhesive systems. METHODS: The immortalized mouse odontoblast cell line (MDPC-23) was plated (30,000 cell/cm2) in 24 well dishes, allowed to grow for 72 h, and counted under inverted light microscopy. Uncured fresh adhesives were added to culture medium to simulate effects of unset adhesive. Three adhesives systems were applied for 120 min to cells in six wells for each group: Group 1) Single Bond (3M), Group 2) Prime & Bond 2.1 (Dentsply), and Group 3) Syntac Sprint (Vivadent). In the control group, PBS was added to fresh medium. The cell number was counted again and the cell morphology was assessed under SEM. In addition, the adhesive systems were applied to circles of filter paper, light-cured for 20 s, and placed in the bottom of 24 wells (six wells for each experimental materials and control group). MDPC-23 cells were plated (30,000 cell/cm2) in the wells and allowed to incubate for 72 h. The zone of inhibition around the filter papers was measured under inverted light microscopy; cell morphology was evaluated under SEM; and the MTT assay was performed for mitochondrial respiration. RESULTS: The fresh adhesives exhibited more toxic (cytopathic effects) to MDPC-23 cells than polymerized adhesives on filter papers, and as compared to the control group. The cytopathic effect of the adhesive systems occurred in the inhibition zone around the filter papers, which was confirmed by the MTT assay and statistical analysis (ANOVA) combined with Fisher's PLSD test. In the control group, MDPC-23 cells were dense on the plastic substrate and were in contact with the filter paper. In the experimental groups, when acid in the adhesive systems was removed by changing the culture medium, or when the adhesives were light-cured, some cells grew in the wells in spite of the persistent cytotoxic effect. SIGNIFICANCE: All dentin adhesive systems were cytotoxic odontoblast-like cells. Both acidity and non-acidic components of these systems were responsible for the high cytopathic effect of those dental materials.

Analysis of Variance↗
PubMedDate not supplied

Affinity thermoprecipitation of yeast alcohol dehydrogenase through metal ion-promoted binding with Eudragit-bound Cibacron blue 3GA.

Metal ion-promoted binding of Saccharomyces cerevisiae alcohol dehydrogenase to Cibacron Blue 3GA was used for its isolation by affinity precipitation with Eudragit-bound dye. The yeast cells were broken and the cell debris was separated by flocculation with poly(ethylene imine). The supernatant containing the enzyme activity was mixed with Eudragit--Cibacron Blue in the presence of zinc ions. The precipitation of the affinity complex was induced by the addition of 50 mM CaCl2 and a subsequent increase in temperature to 40 degrees C. The enzyme was desorbed by treating the precipitate with iminodiacetic acid solution. The procedure resulted in about 66% recovery of enzyme activity with more than 20-fold purification. Recycling of Eudragit--dye for enzyme purification was also shown to be possible.

Acrylic Resins↗
PubMedDate not supplied

Long-term deterioration of composite resin and amalgam restorations.

Previous long-term longitudinal studies of two different methods of placing an auto-cured conventional anterior composite resin, and of a low- and a high-copper amalgam alloy, had shown similar restoration survivals despite the different resin treatment methods used or the types of amalgam alloy placed. Therefore, the aim of the present study was to assess several clinical factors or characteristics of these restorations that were believed to affect the survival of the restorative materials. The 950 composite resin and the 1042 amalgam restorations examined were placed by many operators in numerous patients attending a dental hospital. The composite resin restorations were placed using unetched- and etched-enamel-bonding treatment methods, and the amalgam restorations were polished after insertion. Clinical ratings supplemented by color transparencies were used for the assessment of four factors for the resin, and four factors for the amalgam restoration. Significant deterioration differences were found for several of the clinical factors assessed for both the two different composite resin treatment methods, and for the two different amalgam alloys, which were not directly related to the restoration survivals.

Acid Etching, Dental↗
PubMed2004

Influence of pH and time on organic substance release from a model dental composite: a fluorescence spectrophotometry and gas chromatography/mass spectrometry analysis.

In this study we assessed the influence of pH and time on the degradation and elution of organic substances from the composite resin material, Z-100. To accomplish this, fluorescence spectrophotometry was evaluated as an appropriate technique for the identification of six organic substances (methacrylic acid, methyl methacrylate, hydroquinone, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate and 4,4'-isopropylidenediphenol) that were eluted from resin composite material stored for 24 h or 6 months at pH 4.0, 6.0 or 8.0. In addition, complementary analyses (solid-phase microextraction/gas chromatography/mass spectrometry) were carried out to identify and quantify the substances. The main substances leached from the resin composite were methacrylic acid, triethylene glycol dimethacrylate and hydroquinone. It was concluded that fluorescence spectrophotometry seems to be a suitable, non-destructive technique for the qualitative analysis of eluted organic components. Critical combinations of time and pH allowed the elution of several organic substances, predominantly methacrylic acid, triethylene glycol dimethacrylate and hydroquinone, from the model resin composite, Z-100.

Acrylates↗
PubMed1980

Improved cements containing phosphate polymers.

The mechanical properties of two commercially available dental cements, a zinc phosphate cement and a carboxylate cement, were substantially improved by adding a polymeric phosphate acid to the cement liquids. The improvements can be explained in terms of the change in physico-chemical nature of the modified cements.

Acrylic Resins↗
PubMed1998

Determination of leachable components from four commercial dental composites by gas and liquid chromatography/mass spectrometry.

OBJECTIVES: The purpose of our study was to determine the quality and quantity of leachable residual (co)monomers and additives eluted from various commercial dental composite resins after polymerization. METHODS: Polymerized specimens from four universal hybrid-type composite resins were eluted for 3 days with methanol resp, water. Then all extracts were analysed by gas chromatography/mass spectrometry or liquid chromatography/mass spectrometry using a particle beam interface. RESULTS: In all polymerized composite resin specimens, (co)monomers and various additives as well as contaminants from manufacturing processes were identified. Almost every compound detected in the unpolymerized resins could also be identified in the methanol extracts, but only a few of them were found in the water extracts. From these the co-monomer TEGDMA was extracted in quantities higher than those reported to be cytotoxic in primary human oral fibroblast cultures. CONCLUSIONS: From our results we conclude that the extractable quantities of composite resin components should be minimized, either by reducing the mobility of leachable substances within the set material or by applying less water-soluble components. Furthermore, all ingredients of a dental composite should be declared by the manufacturers, in order to identify those substances in a product which may cause adverse side effects in patients and dental personnel.

4-Aminobenzoic Acid↗
PubMed2003

Microleakage in ceramic inlays luted with different resin cements.

PURPOSE: The objective of this in vitro study was to evaluate the microleakage in ceramic inlays using different resin cements with margins in enamel and cementum/dentin interfaces. MATERIALS AND METHODS: Standard Class II MOD inlay cavities were prepared in 32 noncarious human premolars. The cavities were randomly divided into 4 groups (n = 8): CONTROL GROUP: cavities were treated with Single Bond and incrementally filled with a composite resin (P60); Enforce group: feldspathic ceramic inlays were luted using Prime & Bond 2.1 and Enforce; RelyX group: inlays were cemented with Single Bond and RelyX ARC; Resin Cement group: ceramic inlays were bonded using Single Bond and Resin Cement. Ceramic inlays were previously treated with 10% hydrofluoric acid for 2 min, followed by silane application. After 7 days of storage in distilled water, teeth were submitted to thermocycling. After applying nail varnish, specimens were immersed in 2% aqueous solution of methylene blue for 8 h. After washing, teeth were cut into three sections through the restorations, and the leakage was assessed using a standardized score. RESULTS: Data were submitted to statistical analysis using nonparametric tests (Mann-Whitney and Kruskal-Wallis). Dye leakage at margins in enamel was statistically lower (p < 0.01) than at cementum/dentin interfaces. RelyX ARC performed better (p < 0.05) than resin cement (enamel) and composite restorations (cementum/dentin). No other statistical differences were observed. CONCLUSIONS: Both the material and the substrate interface influenced microleakage of the ceramic inlays.

Acid Etching, Dental↗
PubMed2005

Effect of saliva contamination on microleakage of a bonding system.

UNLABELLED: Saliva contamination is a major clinical problem during restorative dental treatment. Restorative systems must possess sufficient marginal sealing ability to avoid microleakage. PURPOSE: The purpose of this study was to investigate the effect of saliva contamination on the microleakage of cavities restored with Prime & Bond NT and Dyract-AP. METHOD: Cavities were prepared with occlusal margins in enamel and gingival margins in dentine on the buccal surfaces of extracted human permanent premolar teeth. The cavities were etched with phosphoric acid or a non rinse conditioner (NRC). Preparations were distributed randomly into 4 treatment groups (N = 18) consisting of two respective etching methods (phosphoric acid/NRC), each with and without saliva contamination. After the restorative process the samples were thermocycled in dye, sectioned, and scored for microleakage. RESULTS: Contamination with saliva had no significant effect on microleakage on the enamel or dentine sides where phosphoric acid was used as conditioner. Where NRC was used, significantly more microleakage was observed at the enamel sides, but significantly less at the dentine sides.

Analysis of Variance↗
PubMed1992

Five-year study of cervical erosions restored with resin and dentin-bonding agent.

The cumulative retention rate of a microfilled resin in non-undercut cervical abrasion/erosion lesions was studied over a 5-yr period. The enamel was etched and the dentin was pretreated with either Gluma (n = 75) or the first marketed version of Scotchbond (n = 30). The cumulative 5-yr retention rate of the Gluma fillings was 90% and that of the Scotchbond fillings 47% (the 95% confidence limits were 83-98% for Gluma fillings and 27-67% for Scotchbond fillings). The retention rate with both bonding agents was significantly higher in the maxillary arch than in the mandibular arch.

Acid Etching, Dental↗