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Effects of three surface conditioning techniques on repair bond strength of nanohybrid and nanofilled composites.

Nassoohi N, Kazemi H, Sadaghiani M, Mansouri M, Rakhshan V - Dent Res J (Isfahan) (2015 Nov-Dec)

Bottom Line: Their interaction was nonsignificant (P = 0.228).However, the microhybrid composite showed a significantly higher bond strength (Tukey P < 0.05).Sandblasting was significantly superior to the other two methods, which were not different from each other.

View Article: PubMed Central - PubMed

Affiliation: Department of Restorative Dentistry, Islamic Azad University, Dental Branch, Tehran, Iran.

ABSTRACT

Background: Repair bond strength of different composite resins has been assessed in few studies. In addition, reports on the efficacy of surface treatments are debated. Therefore, this in vitro study was conducted to evaluate the effect of three surface treatments on two nanocomposites versus a microhybrid composite.

Materials and methods: In this experimental study, 135 composite blocks (45 specimens per composite) of microhybrid (Filtek Supreme Z250, 3M ESPE, USA), nanohybrid (Filtek Supreme XT, 3M ESPE), and nanofilled (Filtek Supreme Z350, 3M ESPE) were thermocycled (5000 rounds) and then surface roughened (except in a control group of 9 specimens of three composite types). Each composite type was divided into three subgroups of surface treatments: (1) Bur abrading and phosphoric acid (PA) etching, (2) sandblasting and PA etching, and (3) hydrofluoric etching and silane application (n = 15 × 9, complying with ISO TR11405). Composite blocks were repaired with the same composite type but of a different color. Microtensile bond strength and modes of failure were analyzed statistically using two-way analyses of variance, Tukey and Chi-square tests (α = 0.05).

Results: There were significant differences between three composite resins (P < 0.0001) and treatment techniques (P < 0.0001). Their interaction was nonsignificant (P = 0.228). The difference between nanofilled and nanohybrid was not significant. However, the microhybrid composite showed a significantly higher bond strength (Tukey P < 0.05). Sandblasting was significantly superior to the other two methods, which were not different from each other.

Conclusion: Within the limitations of this in vitro study, it seems that microhybrid composite might have higher repair strengths than two evaluated nanocomposites. Among the assessed preparation techniques, sandblasting followed by PA etching might produce the highest bond strength.

No MeSH data available.


Related in: MedlinePlus

A filled template is shown on the right, covered with a Mylar matrix.
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Figure 1: A filled template is shown on the right, covered with a Mylar matrix.

Mentions: The composite blocks (4 mm high and 8 mm in diameter) were molded using stainless steel cylinders. The metal cylinders were incrementally filled with composite layers, from the bottom to the top [Figure 1]. Each composite increment was 2 mm thick. After placing each layer, it was light-cured (40 s) vertically from a 1-mm distance, using a light-emitting diode unit (Demetron II, Kerr, Italy). After curing each composite block, the light-curing unit was calibrated at 600 mW/cm2. To create a smooth composite surface, after placing the final layer of composite and before curing it, a transparent Mylar matrix strip was placed on the surface [Figure 1], and the composite was light-cured.[18] After polymerization, the molds were gently removed.[2]


Effects of three surface conditioning techniques on repair bond strength of nanohybrid and nanofilled composites.

Nassoohi N, Kazemi H, Sadaghiani M, Mansouri M, Rakhshan V - Dent Res J (Isfahan) (2015 Nov-Dec)

A filled template is shown on the right, covered with a Mylar matrix.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4696358&req=5

Figure 1: A filled template is shown on the right, covered with a Mylar matrix.
Mentions: The composite blocks (4 mm high and 8 mm in diameter) were molded using stainless steel cylinders. The metal cylinders were incrementally filled with composite layers, from the bottom to the top [Figure 1]. Each composite increment was 2 mm thick. After placing each layer, it was light-cured (40 s) vertically from a 1-mm distance, using a light-emitting diode unit (Demetron II, Kerr, Italy). After curing each composite block, the light-curing unit was calibrated at 600 mW/cm2. To create a smooth composite surface, after placing the final layer of composite and before curing it, a transparent Mylar matrix strip was placed on the surface [Figure 1], and the composite was light-cured.[18] After polymerization, the molds were gently removed.[2]

Bottom Line: Their interaction was nonsignificant (P = 0.228).However, the microhybrid composite showed a significantly higher bond strength (Tukey P < 0.05).Sandblasting was significantly superior to the other two methods, which were not different from each other.

View Article: PubMed Central - PubMed

Affiliation: Department of Restorative Dentistry, Islamic Azad University, Dental Branch, Tehran, Iran.

ABSTRACT

Background: Repair bond strength of different composite resins has been assessed in few studies. In addition, reports on the efficacy of surface treatments are debated. Therefore, this in vitro study was conducted to evaluate the effect of three surface treatments on two nanocomposites versus a microhybrid composite.

Materials and methods: In this experimental study, 135 composite blocks (45 specimens per composite) of microhybrid (Filtek Supreme Z250, 3M ESPE, USA), nanohybrid (Filtek Supreme XT, 3M ESPE), and nanofilled (Filtek Supreme Z350, 3M ESPE) were thermocycled (5000 rounds) and then surface roughened (except in a control group of 9 specimens of three composite types). Each composite type was divided into three subgroups of surface treatments: (1) Bur abrading and phosphoric acid (PA) etching, (2) sandblasting and PA etching, and (3) hydrofluoric etching and silane application (n = 15 × 9, complying with ISO TR11405). Composite blocks were repaired with the same composite type but of a different color. Microtensile bond strength and modes of failure were analyzed statistically using two-way analyses of variance, Tukey and Chi-square tests (α = 0.05).

Results: There were significant differences between three composite resins (P < 0.0001) and treatment techniques (P < 0.0001). Their interaction was nonsignificant (P = 0.228). The difference between nanofilled and nanohybrid was not significant. However, the microhybrid composite showed a significantly higher bond strength (Tukey P < 0.05). Sandblasting was significantly superior to the other two methods, which were not different from each other.

Conclusion: Within the limitations of this in vitro study, it seems that microhybrid composite might have higher repair strengths than two evaluated nanocomposites. Among the assessed preparation techniques, sandblasting followed by PA etching might produce the highest bond strength.

No MeSH data available.


Related in: MedlinePlus