Abstract
OBJECTIVE: Bracket detachment remains a frequent complication in orthodontic treatment, often resulting in extended treatment duration and increased clinical workload. Nano-hydroxyapatite (n-HAp), due to the excellent biocompatibility and bioactivity, has been explored as a potential filler to improve the performance of dental adhesive systems. This study aimed to evaluate the effect of incorporating 2 wt% n-HAp derived from Amusium pleuronectes (Asian moon scallop) shells into orthodontic adhesive on shear bond strength (SBS) to enamel and on Adhesive Remnant Index (ARI) scores. MATERIALS AND METHODS: Thirty-two extracted human maxillary premolars were randomly divided into two groups (n = 16). The experimental group used orthodontic adhesive modified with 2 wt% n-HAp, while the control group used unmodified commercial adhesive. Standard bracket bonding procedures were performed, followed by SBS testing using a universal testing machine. After debonding, the adhesive remnants were evaluated under a stereomicroscope to determine ARI scores. SBS data were analyzed using an independent t-test, and ARI scores were assessed using the Mann-Whitney U test, with significance set at p < 0.05. RESULTS: The experimental group exhibited a significantly higher mean SBS of 16.54 ± 2.98 MPa compared to 8.91 ± 1.63 MPa in the control group (p < 0.05). ARI scores showed no statistically significant difference between the two groups (p > 0.05), with mean scores of 3.44 ± 1.23 and 3.38 ± 1.22, respectively. CONCLUSION: Incorporation of 2 wt% nano-hydroxyapatite derived from Asian moon scallops into an orthodontic adhesive improved bond strength without altering failure patterns, suggesting its potential as an effective bioactive filler in orthodontic applications.