Evaluation of the cytotoxic and genotoxic effects of orthodontic bonding adhesives upon human gingival papillae through immunohistochemical expression of p53, p63 and p16.
BACKGROUND
Numerous in vitro studies have shown that composite materials, commonly used for restorations in conservative dentistry, and in orthodontics to anchor brackets to the tooth enamel, have cytotoxic and genotoxic effects. The study determined expression of p53, p63 and p16, biomarkers useful for predicting potential genotoxicity.


METHODS
p53, p63 and p16 expression was determined immunohistochemically in the gingival papillae of 99 patients (69 banded orthodontically for at least one year, brackets bonded to teeth with filled flowable composite resin, 30 without orthodontic banding as controls). The papillae samples were removed surgically and examined to evaluate morphological and biological alterations.


RESULTS
In no case were morphological alterations visible by microscopy out of the 69 banded patients; four (5.80%) were positive for p53 and two for p63 expression in the basal and suprabasal layers (2.90%). One patient was positive for p16 (1.45%). No control case was positive for any of the biomarkers (0.00%).


CONCLUSIONS
The significance of p53, p63 and p16 positivity, and whether these proteins may serve as biomarkers to predict the risk of developing oral lesions (dysplasia, oral cancer) is still unclear. Although details of the mechanisms leading to cell death, genotoxicity and cell-cycle delay are not fully understood, resin monomers may alter cell function in the oral cavity.
Department of Pathology, S. Gerardo Hospital, University of Milan-Bicocca, Italy. f.angiero@teos.it
Francesca
F
Angiero
Giampietro
G
Farronato
Enrico
E
Dessy
Sarah
S
Magistro
Rossella
R
Seramondi
Davide
D
Farronato
Stefano
S
Benedicenti
Stefano
S
Tetè
D000293:Adolescent; D000328:Adult; D019941:Cyclin-Dependent Kinase Inhibitor p16; D003738:Dental Cements / Q000633:toxicity*; D005260:Female; D005881:Gingiva / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis*; D009059:Mouth Diseases / Q000139:chemically induced; D009062:Mouth Neoplasms / Q000139:chemically induced; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis*; D055815:Young Adult
C000614131:CDKN2A protein, human; C081876:CKAP4 protein, human; D019941:Cyclin-Dependent Kinase Inhibitor p16; D003738:Dental Cements; D008565:Membrane Proteins; D009363:Neoplasm Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53