Evaluation of two methods of measuring the absorbing capacity of paper points.
OBJECTIVE
This study analyzed two methods of measuring the absorbing capacity of paper points (PP), testing the hypothesis that there is a positive correlation between the results from the percentage of increase mass (PIM) and the linear dye penetration (LDP) methods.


METHODS
The initial dry weight (IDW) of each PP was recorded using a digital balance before 1-mm introduction into one of the dye solutions, 1% methylene blue (MB) or 1% rodamine B (RB), for 10s. The PP's were removed from the solution and weighed (final weight - FW). PIM was calculated from the difference between FW and IDW (n=50). The LDP was measured using a stereomicroscope and a ruler (n=50). Data was statistically analyzed using the Pearson correlation and Student's t tests.


RESULTS
Moderate positive correlations between LDP and PIM methods were found using methylene blue (r=0.6356) and rodamine B (r=0.7743), partially confirming the study hypothesis, and suggesting that results from these two methods should be confronted carefully.


CONCLUSIONS
The results of this study suggest that the most reliable method of measuring the absorbing capacity of paper points is the PIM and investigators should be aware of differences between the two research protocols when comparing results from these two methods (PIM and LDP).
da Cunha Pereira
Charles
C
Dental School, Ulbra, Cachoeira do Sul, RS, Brazil.
Gomes
Maximiliano Schünke
MS
Della Bona
Alvaro
A
Vanni
José Roberto
JR
Kopper
Patrícia Maria Poli
PM
de Figueiredo
José Antônio Poli
JA
D000042:Absorption; D004396:Coloring Agents; D003890:Desiccation; D008422:Materials Testing; D008751:Methylene Blue; D010209:Paper; D012235:Rhodamines; D018915:Root Canal Preparation / Q000295:instrumentation
D004396:Coloring Agents; D012235:Rhodamines; C029773:rhodamine B; D008751:Methylene Blue