Decoloration of 1% methylene blue solution in contact with dental filling materials.
OBJECTIVE
Leakage studies have been performed frequently, since a tight seal provided by various dental fillings has been considered clinically important. The dye penetration experiment using a methylene blue solution as a tracer is one of the most common methods applied in these types of studies. The stability of the colour of methylene blue in contact with six dental filling materials was observed.


METHODS
Silicon rubber tubes and human tooth roots of 10 mm in length and 1.5 mm inner diameter were filled with amalgam, calcium hydroxide, Cavit, Fuji II, mineral trioxide aggregate, or zinc oxide eugenol, 10 tubes or roots for each material. Groups of five tubes or roots filled with the same material were immersed in 0.8 ml 1% methylene blue dye solution. The optical density of the methylene blue solution before immersion and after 24, 48 and 72 h of immersion was measured in a spectrophotometer at 596 nm.


RESULTS
The methylene blue solution was found to be decoloured over time by all the test materials (P < 0.01) except for Fuji II, in both silicone tubes and roots. At 24 h, the optical density value of methylene blue decreased by 73% for the Ca(OH)2/silicone group and 84% for the mineral trioxide aggregate/silicone group.


CONCLUSIONS
Methylene blue is decoloured by some dental filling materials, which may result in unreliable results for these materials in dye leakage studies.
Wu
M K
MK
Department of Cariology Endodontology Pedodontology, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands. M.Wu@acta.nl
Kontakiotis
E G
EG
Wesselink
P R
PR
D017607:Aluminum Compounds / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry; D002126:Calcium Hydroxide / Q000737:chemistry; D002133:Calcium Sulfate / Q000737:chemistry; D003116:Color; D004396:Coloring Agents / Q000737:chemistry*; D003723:Dental Amalgam / Q000737:chemistry; D003736:Dental Cavity Lining; D003738:Dental Cements; D003763:Dental Leakage / Q000175:diagnosis; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent; D004338:Drug Combinations; D004355:Drug Stability; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D007101:Immersion; D008751:Methylene Blue / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D015203:Reproducibility of Results; D012387:Root Canal Filling Materials / Q000737:chemistry; D017640:Silicates / Q000737:chemistry; D012826:Silicone Elastomers; D013053:Spectrophotometry; D013997:Time Factors; D014092:Tooth Root; D015034:Zinc Oxide / Q000737:chemistry; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry
D017607:Aluminum Compounds; D017610:Calcium Compounds; D004396:Coloring Agents; D003738:Dental Cements; D003764:Dental Materials; D004338:Drug Combinations; D005899:Glass Ionomer Cements; D010087:Oxides; D011145:Polyvinyls; D012387:Root Canal Filling Materials; D017640:Silicates; D012826:Silicone Elastomers; D015035:Zinc Oxide-Eugenol Cement; C086631:mineral trioxide aggregate; C084541:Fuji glass-ionomer lining cement; C020872:Cavit; D003723:Dental Amalgam; D002126:Calcium Hydroxide; D015034:Zinc Oxide; D008751:Methylene Blue; D002133:Calcium Sulfate