Many patients regularly take
histamine receptor antagonists, such as
cetirizine, to prevent
allergic reactions, but these
antiallergic drugs may have inadvertent effects on orthodontic treatment. In previous studies,
histamine has been shown to modulate the sterile inflammatory reaction underlying
orthodontic tooth movement. Pertinent effects of
histamine antagonization via
cetirizine during orthodontic treatment, however, have not been adequately investigated. We thus treated male Fischer344 rats either with tap water (control group) or
cetirizine by daily oral gavage corresponding to the clinically used human dosage adjusted to the rat metabolism (0.87 mg/kg) or to a previously published high dosage of
cetirizine (3 mg/kg). Experimental anterior movement of the first upper left molar was induced by insertion of a
nickel-titanium (NiTi) coil spring (0.25 N) between the molar and the upper incisors. Cone-beam computed tomography (CBCT), micro-computed tomography (µCT) images, as well as histological
hematoxylin-
eosin (HE), and
tartrate-resistant acid phosphatase (TRAP) stainings were used to assess the extent of tooth movement, cranial growth,
periodontal bone loss,
root resorptions, and osteoclast activity in the periodontal ligament. Both investigated
cetirizine dosages had no impact on the
weight gain of the animals and, thus, animal welfare. Neither the extent of tooth movement, nor cranial growth, nor
root resorption, nor
periodontal bone loss were significantly influenced by the
cetirizine dosages investigated. We, thus, conclude that
histamine receptor antagonist
cetirizine can be used during orthodontic treatment to prevent
allergic reactions without clinically relevant side effects on
orthodontic tooth movement.