Hur kan styrkan mellan gammal och ny komposit optimeras?
I en laboratoriestudie vid NIOM, Oslo, har bindningsstyrkan mellan gammal och ny komposit analyserats. Syftet var, att undersöka hur silanisering i kombination med olika adhesiver, som härdades eller lämnades ohärdade före ny komposit, påverkade bindningsstyrkan.
Resultaten visade, att när adhesiven inte härdades före påläggning av ny komposit så ökade styrkan i bindningen mellan kompostmaterialen signifikant. Detta var fallet för samtliga använda adhesiver och kombinationer, oavsett om gammal komposit silaniserades eller ej.
Författarna konkluderar, att när en adhesiv inte härdades före applicering av kompositmaterialet så erhölls den högsta bindningsstyrkan till gammal komposit. Silaniseringen skall göras precis före applicering av adhesiv för bästa resultat.
Abstract
Objectives:
To evaluate the micro-tensile repair bond strength between aged and new composite, using silane and adhesives that were cured or left uncured when new composite was placed.
Methods:
Eighty Filtek Supreme XLT composite blocks and four control blocks were stored in water for two weeks and thermo-cycled. Sandpaper ground, etched and rinsed specimens were divided into two experimental groups: A, no further treatment and B, the surface was coated with bis-silane. Each group was divided into subgroups: (1) Adper Scotchbond Multi-Purpose, (2) Adper Scotchbond Multi-Purpose adhesive, (3) Adper Scotchbond Universal, (4) Clearfil SE Bond and (5) One Step Plus. For each adhesive group, the adhesive was (a) cured according to manufacturer’s instructions or (b) not cured before repair. The substrate blocks were repaired with Filtek Supreme XLT. After aging, they were serially sectioned, producing 1.1 × 1.1 mm square test rods. The rods were prepared for tensile testing and tensile strength calculated at fracture. Type of fracture was examined under microscope.
Results:
Leaving the adhesive uncured prior to composite repair placement increased the mean tensile values statistically significant for all adhesives tested, with or without silane pretreatment. Silane surface treatment improved significantly (p < 0.001) tensile strength values for all adhesives, both for the cured and uncured groups. The mean strength of the control composite was higher than the strongest repair strength (p < 0.001).
Conclusions:
Application of freshly made silane and a thin bonding layer, rendered higher tensile bond strength. Not curing the adhesive before composite placement increased the tensile bond strength.
Reference
Effect of curing and silanizing on composite repair bond strength using an improved micro-tensile test method
Eliasson ST, Dahl JE
Acta Biomaterialia Odontologica Scandinavica 2017, 3:1, 21-29
Källa: NIOM
