Orthodontic adhesives induce human gingival fibroblast toxicity and inflammation.
OBJECTIVE
To test the null hypothesis that the resin base and the resin hybrid glass ionomer base adhesives do not cause inflammation after contacting primary human gingival fibroblasts in vitro.


METHODS
The resin base and resin hybrid glass ionomer base adhesives were used to treat human gingival fibroblasts to evaluate the survival rate using MTT colorimetric assay to detect the level of cyclooxygenase-2 (COX-2) mRNA by reverse transcription polymerase chain reaction (RT-PCR) technique and COX-2 protein expression using Western blot analysis. The results were analyzed using one-way analysis of variance (ANOVA). Tests of differences of the treatments were analyzed using the Tukey test and a value of P < .05 was considered statistically significant.


RESULTS
The paste and primer of the resin base adhesive and the liquid of glass ionomer adhesive showed decreasing survival rates after 24 hours of treatment (P < .05). All orthodontic adhesives induced COX-2 protein expression in human gingival fibroblasts. The exposure of quiescent human gingival fibroblasts to adhesives resulted in the induction of COX-2 mRNA expression. The investigations of the time-dependent COX-2 mRNA expression in adhesive-treated human gingival fibroblasts revealed different patterns.


CONCLUSIONS
The hypothesis is rejected. For orthodontic patients with gingival inflammation, except for those with oral hygiene problems, the activation of COX-2 expression by orthodontic adhesive may be one of the potential mechanisms.
Huang
Tsui-Hsien
TH
Chung Shan Medical University Hospital, Institute of Stomatology, Institute of Oral Material Science, Taichung, Taiwan.
Liao
Pao-Hsin
PH
Li
Han Yu
HY
Ding
Shinn Jyh
SJ
Yen
Min
M
Kao
Chia-Tze
CT
D000269:Adhesives / Q000009:adverse effects* / Q000633:toxicity; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002648:Child; D003124:Colorimetry; D004396:Coloring Agents; D020770:Compomers / Q000009:adverse effects / Q000633:toxicity; D051546:Cyclooxygenase 2 / Q000032:analysis / Q000235:genetics; D003738:Dental Cements / Q000009:adverse effects* / Q000633:toxicity; D005260:Female; D005347:Fibroblasts / Q000187:drug effects* / Q000473:pathology; D005881:Gingiva / Q000187:drug effects* / Q000473:pathology; D005891:Gingivitis / Q000139:chemically induced; D005899:Glass Ionomer Cements / Q000009:adverse effects / Q000633:toxicity; D006801:Humans; D008422:Materials Testing; D009967:Orthodontic Appliances; D012333:RNA, Messenger / Q000032:analysis; D019279:Resin Cements / Q000009:adverse effects / Q000633:toxicity; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013778:Tetrazolium Salts; D013844:Thiazoles; D013997:Time Factors
D000269:Adhesives; D004396:Coloring Agents; D020770:Compomers; D003738:Dental Cements; D005899:Glass Ionomer Cements; D012333:RNA, Messenger; D019279:Resin Cements; D013778:Tetrazolium Salts; D013844:Thiazoles; D051546:Cyclooxygenase 2; C022616:thiazolyl blue