Evaluation of the shear bond strength of various adhesives on the surface of enamel irradiated with various doses of radiotherapy

Fahrzadeh N., Tunca M.

AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS, vol.165, no.3, pp.285-293, 2023 (SCI-Expanded) identifier identifier



We aimed to compare the shear bond strength (SBS) forces on the enamel surface with 2 adhesives after treatment with various radiation doses.


A total of 120 premolars were included in the study. The teeth were randomly divided into 5 main groups (n = 24): negative control (without aging), positive control (with aging), 40 Gy, 60 Gy, and 70 Gy radiation. The 40 Gy, 60 Gy, and 70 Gy groups underwent conventional radiotherapy 5 days a week with a dose of 2 Gy each day. After the radiotherapy, all samples except the negative control group were subjected to thermal cycle aging. In all 5 groups, the specimens were divided into 2 subgroups, and half were bonded using 2 adhesives. After bonding, the universal Shimadzu test device was used to analyze the SBS. After the test, the tooth surfaces were examined under a stereomicroscope to determine the adhesive remnant index.


When adhesives were compared, Biofix adhesive’s bond strength value was statistically higher in the 40 Gy group than in the Transbond XT group (P = 0.001). The SBS value was higher in all irradiated groups than in nonirradiated groups (P = 0.001). When the adhesive remnant index score was analyzed, no significant difference was found among the groups.


The SBS increased in irradiated teeth compared with unirradiated teeth, and the SBS values of both adhesives were within the acceptable limits in all radiation groups.