Biological effects of flowable resin composite on erythrocytes and lymphocytes using an in vitro model.
OBJECTIVE
The purpose of the study was to evaluate the biological effects of a flowable resin composite on erythrocytes and rat spleen lymphocytes (RSL) using an in vitro model.


METHODS
Rat spleen lymphocytes were placed into microcentrifuge tubes as a pulp model. An artificial pulp exposure was made through the top of the microcentrifuge tube with a 16G needle. The exposure site was filled with a flowable resin composite and photo-polymerized, and the other specimens were not polymerized. The survival rates were determined by a haemocytometer. Red blood cell (RBC) suspension (0.5%) was reacted with the flowable resin composite. The haemolytic activity was evaluated at room temperature (20 degrees C) using a supernatant of each sample by measuring 545 nm of absorbency with a spectrophotometer. To evaluate the effect of flowable resin composite on RBCs, supernatant and precipitated samples were analysed by sodium dodecyl sulphate-polyacrylamide gel (SDS-PAGE).


RESULTS
The cell survival rate of the polymerized group was significantly lower compared with that of the nonpolymerized group at the same areas (P < 0.05). The values of haemolysis (absorbency) were 2.16 for the polymerized group, 2.14 for the nonpolymerized group, and 2.18 for the control group (saline). There were no significant differences among them (P > 0.05). The protein component in the supernatant and precipitate exhibited the same reaction with flowable resin composite regardless of the completion of the polymerization, resulting in no change of protein band mobility on SDS-PAGE.


CONCLUSIONS
The degree of haemolysis was not influenced by the completion of polymerization. The flowable resin composite tested provoked an adverse effect on lymphocytes when it was not polymerized and the degree of haemolysis was not affected by the status of the polymerization.
Yamaguchi
H
H
Department of Periodontics and Endodontics, Tsurumi University, School of Dental Medicine Yokohama, Japan. yamaguchi-h@tsurumi-u.ac.jp
Suzuki
S
S
Kobayashi
K
K
Arai
T
T
D000818:Animals; D002470:Cell Survival; D003188:Composite Resins / Q000528:radiation effects / Q000633:toxicity*; D003785:Dental Pulp Capping / Q000009:adverse effects*; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000187:drug effects*; D006244:Hardness; D006461:Hemolysis; D008297:Male; D044367:Phase Transition; D011109:Polymethacrylic Acids / Q000528:radiation effects / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D019279:Resin Cements / Q000528:radiation effects / Q000633:toxicity*; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000187:drug effects*
D003188:Composite Resins; D011109:Polymethacrylic Acids; D019279:Resin Cements; C501418:Unifil LoFlo Plus