Objectives: The aim of this in vitro investigation was to evaluate the surface hardness (SH) of an experimental glass ionomer restorative Ketac™ Molar New Formulation (KMNF) in comparison to other glass ionomer restoratives. KMNF has lower viscosity compared to Ketac Molar Aplicap (KMA & KMNF, 3M ESPE).
Methods: KMNF and eleven other glass ionomer restoratives of various brands were submitted to a SH test. Other materials tested were riva self cure, riva self cure HV (RSC & RHV, SDI Limited), Omnifill C (OMF,Omnident®), Ionofil Molar AC, Ionofil Plus AC (IFM & IFP, VOCO GmbH), ChemFil®Rock (CFR, Dentsply Detrey GmbH), Fuji IX GP, Equia Fil™ and Equia Coat™ (FIX & EQFC, GC Dental), Ketac Molar Quick Aplicap and Ketac Fil Plus Aplicap (KMQ & KFP, 3M ESPE). A minimum of 6 cylindrical specimens (Ø 6 mm, Thickness 4 mm) were made per material and stored in water at 36 °C. SH was tested 24h after start of mixing with a ball shaped indenter. SH was calculated in analogy to ISO 2039-1.
Results: The following table summarizes the SH values measured. One-way Anova showed that type of material (P < 0.05) had a significant effect on hardness. Groups with no statistically significant difference are marked with the same character.
Material
| 24h Surface Hardness [MPa] |
KMNF
| 668 ± 68a |
KMA
| 647 ± 34a |
RHV
| 614 ± 71a,b |
KMQ
| 601 ± 68a,b |
FIX
| 559 ± 71b,c |
EQFC
| 499 ± 145c |
KFP
| 401 ± 36d |
RSC
| 387 ± 17d,e |
IFM
| 386 ± 49d,e |
OMF
| 374 ± 18d,e |
CFR
| 350 ± 62d,e |
IFP
| 321 ± 34e |
Conclusion: KMNF showed higher SH values than FIX, EQFC, KFP, RSC, IFM, OMF, CFR, IFP and SH values comparable to clinically proven materials like KMA, KMQ and RHV.