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At least 811 records · Page 45Linked to original sources
PubMed2004

Self-etching adhesives improve the shear bond strength of a resin-modified glass-ionomer cement to dentin.

PURPOSE: Despite the improvements of resin-modified glass-ionomer cements, the dentin bond strength of these materials remains inferior to that provided by "bonding system/composite" combinations and limits the clinical use of RMGIC. The objective of this in vitro study was to investigate the effect of new self-etching bonding systems on the adhesion to dentin of Fuji II LC. MATERIALS AND METHODS: Seven recent self-etching systems were studied (Clearfil SE Bond = CSE, Optibond Solo Plus Self-Etching Primer = OSP, One Up Bond F = OUP, Mac Bond II = MB2, Xeno III = XB3, ADPER Prompt-L-Pop = ADP, Unifil Bond = UB) and compared with Cavity Conditioner (C). After the bonding procedure, a resin-modified glass-ionomer cylinder (Fuji II LC) was bonded to the surface using a Teflon mold (diameter: 3 mm; height: 5 mm). The different specimens were tested in a shear bond mode (0.5 mm/min). Statistical analyses were performed with one-way ANOVA and Fischer PLSD test (p < 0.05). RESULTS: The one-way ANOVA revealed a significant influence of the surface treatment parameter (p < 0.0001). The lowest shear bond strength values were obtained with Cavity Conditioner. The highest values were obtained with MB2. The multiple comparisons revealed that ADP = OBP = XB3 = OUB = UB = CSE and that UB = CSE = MB2. CONCLUSION: The application of the 7 self-etching adhesives tested in this study improves the dentin shear bond strengths of Fuji II LC. This increase depended on the adhesive system and ranged from 50% for ADP up to 130% for MB2.

Acrylic Resins↗
PubMedDate not supplied

Clinical evaluation of a polyacid-modified resin composite-based fissure sealant: two-year results.

A 24-month clinical study was carried out to evaluate and compare the retention rate, marginal integrity and caries preventing effects of a polyacid-modified resin composite based fissure sealant, Dyract Seal, to that of a resin based fluoride fissure sealant, Delton FS+. Fifty-three patients (27 female and 26 male), 7 to 10 years old, were included in the study. At baseline, a total of 192 permanent first molars were sealed with either fissure sealant (n=96, each), using invasive technique. The sealed teeth were evaluated at post-operative 3, 6, 12 and 24 months with respect to evaluation parameters. The data were analyzed with the Chi-Square tests where alpha=0.05. There were no statistically significant differences between fissure sealants as regards to retention and prevention of caries for all periods of the evaluation (p>0.05). However, regarding marginal integrity of the sealants, Delton FS+ gave significantly better results than Dyract Seal for the 3-, 6- and 12-month evaluations, respectively (p<0.05). In conclusion, the use of Dyract Seal on permanent molars with invasive technique was found to be clinically comparable to Delton FS+ for the 24-month evaluation period.

Bisphenol A-Glycidyl Methacrylate↗
PubMedDate not supplied

Wear behavior of new composite restoratives.

This study investigated the wear resistance of recently introduced nanofill (Filtek Supreme [FS], 3M-ESPE) and ormocer (Admira [AM], Voco) composites and compared their wear characteristics to microfill (Filtek A110 [AO], 3M-ESPE]), minifill (Esthet X [EX], Dentsply; Filtek Z250 [ZT], 3M-ESPE) and polyacid-modified (Dyract AP [DY], Dentsply) composites. Six specimens were made for each material. The specimens were conditioned for one week in distilled water at 37 degrees C and subjected to wear testing at 20 MPa contact stress against SS304 counter-bodies using reciprocal compression-sliding wear instrumentation. Distilled water was used as lubricant. Wear depth (microm) was measured using profilometry every 5,000 cycles up to 20,000 cycles. The results were analyzed using ANOVA/Scheffe's test (p<0.05). Wear of the materials was cycle and fatigue dependent. Although no significance in wear was observed between materials after 5,000 cycles of wear testing, significant differences were observed at 10,000 cycles and greater. After 20,000 cycles of wear testing, ranking was as follows: ZT > DY >AM > AO > FS > EX. Wear ranged from 39.90 microm for EX to 113.32 microm for ZT. The wear resistance of ZT and DY was significantly lower than AO, FS and EX In addition, ZT experienced significantly more wear than AM. Under the conditions of this in-vitro study, the wear resistance of nanofill and ormocer composites was comparable or superior to polyacid-modified, microfill and minifill composites.

Analysis of Variance↗
PubMedDate not supplied

The effect of home bleaching agents on the surface roughness of tooth-colored restoratives with time.

This study evaluated the effects of home bleaching agents on the surface roughness of composite restoratives. Two home bleaching gels (10% and 15% carbamide peroxide, Opalescence) and five different tooth-colored restorative materials from the same manufacturer (3M-ESPE) were selected. They included microfill (Filtek A110 [FO]), flowable (Filtek Flow [FF]), polyacid-acid modified (F2000 [FT]) and minifill (Z100 [ZO]; Filtek Z250 [ZT]) composites. Thirty-six specimens of each material were fabricated, randomly divided into three groups (n=12) and treated as follows: Group 1-Stored in distilled water, Group 2-Bleached with 10% carbamide peroxide (CP) eight hours/day; Group 3-Bleached with 15% CP eight hours/day. All treatment was conducted at 37 degrees C and fresh gel applied and rinsed off daily for eight weeks. For the bleached groups, the specimens were stored in distilled water at 37 degrees C during the hiatus periods. All the specimens were subjected to roughness testing (Ra) at weeks 0, 1, 2, 4, 6 and 8 using a profilometer. The results were analyzed using general linear model with Scheffe's post-hoc tests at significance level 0.05. The results showed that the effect of bleaching on surface roughness was material and time dependent. ZT was not affected by bleaching treatment, while FT was significantly roughened after one week of bleaching with 15% CP compared to the control group. FO, FF and ZO were not significantly roughened until eight weeks of bleaching. Repolishing or replacement of tooth-colored restorations may be required after bleaching procedures.

Analysis of Variance↗
PubMed2004

Effect of bur-cut dentin on bond strength using two all-in-one and one two-step adhesive systems.

PURPOSE: To compare the microtensile bond strength (MTBS) of two all-in-one adhesive systems and one experimental two-step self-etching adhesive system to two types of bur-cut dentin. MATERIALS AND METHODS: Using one of the three adhesives, Xeno CF Bond (Xeno), Prompt L-Pop (PL), or the experimental two-step system ABF (ABF), resin composite was bonded to flat buccal and root dentin surfaces of eight extracted human premolars. These surfaces were produced using either regular-grit or superfine-grit diamond burs. After storage overnight in 37 degrees C water, the bonded specimens were sectioned into six or seven slices approximately 0.7 mm thick perpendicular to the bonded surface. They were then subjected to microtensile testing. The surfaces of the fractured specimens were observed microscopically to determine the failure mode. In addition, to observe the effect of conditioning, the two types of bur-cut dentin surfaces were conditioned with the adhesives, rinsed with acetone, and observed with SEM. RESULTS: When Xeno and PL were bonded to dentin cut with a regular-grit diamond bur, MTBS values were lower than to superfine bur-cut dentin, and failures occurred adhesively at the interface, whereas the experimental two-step adhesive showed no significant difference in microtensile bond strength between two differently cut surfaces. CONCLUSION: The all-in-one adhesives tested here improved bond strengths when bonded to superfine bur-cut dentin as a substrate, whereas the experimental two-step adhesive system showed unchanged bonding to both regular and superfine bur-cut dentin surfaces.

Acetone↗
PubMed2004

In vitro testing of all-in-one adhesives as fissure sealants.

PURPOSE: To evaluate the clinical efficacy of all-in-one adhesives as fissure sealants. METHODS: Resin-enamel bonded specimens were fabricated between polished and ground enamel surfaces using two all-in-one adhesives (One-Up Bond F and Xeno CF Bond) and two resin sealants (Teethmate F-1 and Helioseal F). Specimen beams were prepared and microtensile bond tests were performed at a crosshead speed of 1 mm/minute. The bond strengths obtained were subjected to one-way ANOVA and Scheffe's F test (P < 0.05: n=12 for each group). To evaluate the etching effect of phosphoric acid and the all-in-one adhesives, the treated enamel surfaces (37% phosphoric acid, 40% phosphoric acid, or all-in-one adhesives) were examined by FE-SEM. RESULTS: The bond strengths of the two all-in-one adhesives tested to the polished enamel surface were significantly lower (P < 0.05) than to ground enamel. However, no significant differences (P > 0.05) were found between the polished and ground enamel surfaces for resin sealants using phosphoric acid. Under SEM examination, 37% or 40% phosphoric acid etched the enamel surface more than all-in-one adhesives.

Acid Etching, Dental↗
PubMed2004

[Observation of the clinical effects of two kinds of resin materials for restoring the defects of maxillary incisor].

To analyse and compare the effects of the resin materials of etched and nonetched groups in restoring the defect of maxillary incisor. 120 teeth were divided into two groups and filled by two kinds of materials. One year follow up results was studied. The effects of retention had no significant difference between the two groups, but the nonetched group had a lower stimulation to the pulp than the other one in restoring middle to deep caries. Compared to the etched group, the nonetched materials of resin has lower stimulation to pulp, more adhesion and higher success rate.

Adolescent↗
PubMedDate not supplied

Clinical evaluation of a polyacid-modified resin composite under different conditioning methods in primary teeth.

This study evaluated the clinical performance of a polyacid-modified resin composite, Dyract AP (De Trey/Dentsply), under different conditioning methods in primary teeth. Eighty-one box-shaped cavity preparations (three restorations per patient) on the mesial or distal surfaces of primary first or second molars were prepared in 27 patients. The cavity preparations were either non pre-treated or pre-treated with 36% phosphoric acid or NRC (De Trey/Dentsply). The teeth were restored with Prime & Bond NT (De Trey/Dentsply) and Dyract AP. The restorations were evaluated at baseline and 6, 12 and 18-month recalls according to the modified Ryge criteria by two calibrated operators. The data obtained from the clinical assessment of all restorations were subjected to statistical analysis by chi-square-tests at a 0.05 level of significance. The ratings of each criteria were compared among each evaluation period between treatment groups. Statistical analysis revealed no significant difference among each evaluation period between groups in regard to color match, marginal discoloration, marginal adaptation, secondary caries, surface texture, anatomic form and retention.

Acid Etching, Dental↗
PubMedDate not supplied

Fluoride releasing materials: their anti-cariogenic properties tested in in vitro caries models.

The anti-cariogenic properties of three fluoride-releasing materials on root surfaces were evaluated using two different caries models. Standardized cavities were prepared in dentin specimens and restored with either glass-ionomer, resin-modified glass-ionomer, polyacid-modified resin composite or resin composite material. Two groups of 56 specimens were demineralized using a microbial caries model for three days, while another 56 specimens were demineralized using a chemical demineralization model for three days. Lesions around the restorations were measured with a confocal laser scanning microscope. Glass ionomers demonstrated significant anti-cariogenic properties when exposed to the chemical model. However, no significant anti-cariogenic properties were observed with the microbial caries model. In conclusion, the fluoride releasing materials showed different anti-cariogenic properties in root surfaces under the different caries models, suggesting that caution should be exercised when trying to extrapolate the results of in vitro studies to the clinical situation.

Cariostatic Agents↗
PubMedDate not supplied

Influence of environmental conditions on dentin bond strengths of one-application adhesive systems.

Resin composites are considered susceptible to environmental conditions that might affect bond strength. This study investigated the influence of relative humidity and temperature on the dentin bond strength of newly developed one-application adhesive systems. Bonding systems employed in this study were five commercial one-application adhesive systems. Labial surfaces of bovine incisors were ground wet on 600-grit SiC paper. The teeth were transferred to a controlled temperature and humidity chamber and the specimens were prepared in six different environmental conditions, A) 25 +/- 0.5 degrees C, 50 +/- 5% RH, B) 25 +/- 0.5 degrees C, 80 +/- 5% RH, C) 25 +/- 0.5 degrees C, 95 +/- 5% RH, D) 37 +/- 0.5 degrees C, 50 +/- 5% RH, E) 37 +/- 0.5 degrees C, 80 +/- 5% RH, F) 37 +/- 0.5 degrees C, 95 +/- 5% RH. The dentin surfaces were treated according to each manufacturer's instructions. Resin composites of each bonding system were condensed into a mold and light irradiated. After storage in 37 degrees C water for 24 hours, 10 specimens per group were tested in a shear mode in a testing machine at a crosshead speed of 1.0 mm/minute. Statistical analysis was carried out with one-way ANOVA followed by Duncan's multiple range tests at a p-value of 0.05. The dentin bond strengths of one-application adhesive systems decreased with increasing RH. These data suggest that the relative high humidity in the oral environment needs consideration in developing clinical procedures for management of these one-application adhesive systems.

Animals↗
PubMed2004

Effects of bonded composites vs. amalgam on resistance to cuspal deflection for endodontically-treated premolar teeth.

PURPOSE: To determine, by means of a non-destructive experimental procedure, the extent to which tooth cusps are weakened by endodontic procedures and the effectiveness of adhesive bonding restoration in reducing cuspal deflection as a function of different restorative procedures. METHODS: A mechanically controlled loading device induced cuspal deflection by axial force (range 98-294 N) on an occlusal surface while LTS laser twin sensors registered the amount of deflection. Cusp deflection values, in microns, were recorded for each tooth. Thirty sound maxillary premolars teeth were sequentially evaluated in the following conditions: A) intact tooth; B) completion of endodontic and restorative procedures. Teeth were randomly divided into five groups and restored respectively with: A) amalgam (Dispersalloy); B) Spectrum TPH; C) Surefil; D) Esthet-X; E) Esthet-X + Dyract Flow. RESULTS: The average loading force needed to induce 1 microm cusp deflection was evaluated, for all groups, in intact teeth (range 49.52-58.76 N/microm) and in restored teeth (range 8.56 - 47.05 N/microm). Statistical analysis (ANOVA for repeated measures) has been performed. Mean structural recovery values after restorative treatment were 17% with amalgam, 60% with Spectrum TPH, 59% with SureFil, 54% with Esthet-X, and 99% with Esthet-X/Dyract.

Adolescent↗
PubMed2004

Surface hardness properties of resin-modified glass ionomer cements and polyacid-modified composite resins.

In this study the top and bottom surface hardness of two polyacid-modified composite resins (PMCRs), one resin-modified glass ionomer cement (RMGIC), and one composite resin were evaluated. The affect of water storage on their hardness was also investigated. The study was conducted using four different groups, each having five specimens obtained from fiberglass die molds with a diameter of 5 mm and a height of 2 mm. Measurements were made on the top and bottom surface of each specimen and recorded after 24 hours and again at 60 days. All tested materials showed different hardness values, and the values of top surfaces of the specimens were found to be higher than the bottom surface in all test groups. There was no statistical difference in the Vickers hardness (HV) values when the test specimens were kept in water storage. In conclusion Hytac displayed microhardness values higher than Vitremer and Dyract. We found the order of HV values to be Surfil > Hytac > Dyract > Vitremer, respectively. Vitremer presented the lowest microhardness level and Surfil the highest.

Analysis of Variance↗
PubMedDate not supplied

Effect of a nonrinse conditioner on the durability of a polyacid-modified resin composite fissure sealant.

PURPOSE: The aim of this study was to evaluate the effect of the simplified conditioning on durability of polyacid-modified resin composite (PMRC; Dyract Seal) fissure sealants. The effectiveness of a nonrinsing conditioner (NRC) on retention of PMRC sealants (92) was studied in a split-mouth design. METHODS: The enamel of 1 molar was pretreated with NRC and coated with Prime & Bond NT (Dentsply DeTrey, Konstanz, Germany)/PMRC. The contralateral molar was conditioned with 36% phosphoric acid and sealed with Delton. The sealant retention was evaluated during 2 years. In addition 49 pairs were sealed with Prime & Bond NT/PMRC after conditioning with 36% phosphoric acid and evaluated after 1 year. RESULTS: Significantly higher loss rates at 1 and 2 years were observed for the NRC/Prime & Bond NT/PMRC sealants. At 2 years, partial and total loss rates for Delton were 23% and 11%, and for NRC/Prime & Bond NT/PMRC sealants were 44% and 40%, respectively. At 1 year, phosphoric acid-conditioned Prime & Bond NT/PMRC sealants showed significantly better retention than the NRC-conditioned PMRC sealants and the phosphoric acid-conditioned Delton sealants. CONCLUSIONS: Conditioning with NRC prior to sealant application cannot be recommended.

Adolescent↗
PubMed2005

[Study of shearing strength between layers of light curing composite Esterfill PHOTO].

There was determined shearing strength of monolit samples of light curing material and samples received by modeling of further layers on surfaces with and without inhibited layer and also tensile strength of layers connected with the help of light curing adhesive. The study was performed on enamel, dentine and cutting edge masses from set of light curing material Esterfill PHOTO for prosthetic purposes. The received results showed that shearing strength between layers of enamel, dentine and cutting edge masses of Esterfill PHOTO varied between 22 and 28 MPa and tensile force divided by the nominal surface area did not depend upon the way of sample modeling. Distraction zone represented half of the cone turn out of substrate. More rigid material chopped in the process of distraction lesser volume off substrate. For prosthetic purposes it was recommended to use the equipment allowing to combine the final photopolymerization of the article with annealing under high temperature conditions or make annealing of the ready article after photopolymerization.

Adhesiveness↗
PubMed2004

Polish retention of new aesthetic restorative materials over time.

New aesthetic restorative materials claiming superior polish retention have recently been introduced. This study compared polish retention of eight different types of aesthetic restorative materials including ormocer and nanofill composites over a 6-month ageing period in distilled water. Eight specimens of each material were fabricated and roughened with 320 grit grinding paper using a lapping device and finished/polished with a graded abrasive disk system. Mean roughness was then determined using a surface profilometer. The specimens were then stored in distilled water at 37 degrees C and roughness measurements were repeated after 3 and 6 months of ageing. Mean surface roughness values ranged from 0.15 to 0.68 microm for immediate readings and 0.17 to 1.02 microm after ageing for 6 months. With the exception of the highly viscous glass ionomer cement, the surface polish of most materials did not deteriorate much over time. At all time intervals, composite materials based on ormocer and nanomer technology were significantly smoother than all other materials evaluated.

Ceramics↗
PubMedDate not supplied

Effect of hygiene maintenance procedures on surface roughness of composite restoratives.

This study investigated the effect of various hygiene maintenance procedures on the surface finish of minifill (Filtek A110 [AO], 3M-ESPE), flowable (Filtek Flow [FF], 3M-ESPE) and poly-acid-modified (F2000 [FT], 3M-ESPE) composites. Procedures included pumice-water slurry with rotating brush (PB), pumice-water slurry with rotating rubber cup (PC), prophylaxis paste with rubber cup (ZC), prophylaxis gel with rubber cup (GC) and air-powder polishing (AP). Specimens not exposed to these procedures were used as the control group. For each material, 48 specimens (3-mm long x 3-mm wide x 2-mm deep) were made and stored in distilled water at 37 degrees C for one month. The specimens were then treated with 1200 grit sandpaper using a lapping device, stored for an additional two months in distilled water at 37 degrees C and randomly divided into six groups (n=8). The mean surface roughness (Ra, microm) of the specimens after exposure to the various hygiene procedures was determined using a surface profilometer. Data was subjected to ANOVA/Scheffe's test at significance level 0.05. Mean Ra values ranged from 0.09 to 2.17, 0.06 to 1.38 and 0.38 to 1.25 for AO, FF and FT, respectively. The effect of hygiene procedures on surface roughness was material dependent. Among the various procedures, the smoothest surface was observed after treatment with prophylaxis gel and the roughest with air-powder polishing. For all materials, the use of pumice-water slurry with brush also caused significant roughening. Composite restorations may require re-polishing after exposure to some hygiene maintenance procedures, as Ra values exceeded the critical threshold surface roughness for bacterial adhesion (0.2 microm).

Air Abrasion, Dental↗
PubMed2004

Microtensile bond strength of self-etching adhesives to enamel and dentin.

PURPOSE: To measure the microtensile bond strength to enamel and dentin of three self-etching adhesives in comparison with a total-etch two-step system as a control. MATERIALS AND METHODS: A total of 40 extracted human molars were stored in saline solution until use, then divided into 4 groups of 10 teeth (one group per adhesive system). Half of each of these groups underwent bond strength tests on enamel, and the other half was used for adhesion testing on dentin. The following experimental groups (n = 5) were then formed: E(1) Adper Prompt-L-Pop (AP, 3M ESPE) on enamel; E(2) Xeno CF II (X, Sanking Kogyo) on enamel; E(3) AdheSE (AS, Ivoclar-Vivadent) on enamel; E(4) Excite (EX, Ivoclar-Vivadent) on enamel; D(1) AP on dentin; D(2): X on dentin; D(3) AS on dentin; D(4) EX on dentin. Each tooth yielded 15 to 20 sticks about 0.9 x 0.9 mm in cross-sectional area for microtensile testing. Specimens were loaded in tension at a crosshead speed of 0.5 mm/minute, and bond strength at failure was calculated in MPa. A two-way ANOVA was applied to test for significance of the differences among the groups. RESULTS: The bond strength values of Excite (the control) were significantly higher than those of the test products on enamel (42.92+/-4.8 MPa) and on dentin (45.80+/-5.79 MPa). The self-etching adhesives AdheSE (28.48+/-4.71 MPa) and Xeno CF II (27.22+/-2.74 MPa) revealed significantly stronger adhesion than Adper Prompt-L-Pop (20.16+/-2.07 MPa) on dentin. On enamel, all self-etching test materials performed similarly. The substrate did not appear to have a significant influence on adhesion, as each material reached comparable levels of bond strength on enamel and dentin. CONCLUSION: On both substrates the self-etching adhesives tested performed significantly worse than did the total-etch system.

Acrylic Resins↗