Modulation of Osteoclast Differentiation using Statin-Loaded Carbonate Hydroxyapatite Nanoemulsion during Orthodontic...

Orthodontic relapse remains a persistent biological concern, predominantly attributed to early posttreatment activation of osteoclasts. This study aimed to assess the potential of a simvastatin-loaded carbonate hydroxyapatite (CHA) nanoemulsion in attenuating osteoclastogenesis and improving alveolar bone stability following orthodontic treatment.

An in vivo randomized controlled experimental design was conducted using 32 male Wistar rats (Rattus norvegicus, 200-250 g). Orthodontic tooth movement was initiated with a 30 cN nickel-titanium closed-coil spring for 7 days, followed by 7 days of stabilization. After appliance removal, rats were divided into control and experimental groups. The treatment group received local intrasulcular application of statin-CHA nanoemulsion (0.05 mg simvastatin +0.1 mg CHA/15 μL) on days 0, 4, and 7. Alveolar bone specimens were harvested on days 0, 1, 7, and 14 for histological examination (H and E staining). Data were analyzed using two-way analysis of variance followed by Tukey's post hoc test (P < 0.05).

Osteoclast numbers peaked on day 1 in both groups but were significantly lower in the treatment group (17.25 ± 0.95) than in controls (30.00 ± 1.15; P < 0.001). Suppression of osteoclast activity persisted up to day 14 (P < 0.05).

Simvastatin-loaded CHA nanoemulsion effectively inhibits osteoclast differentiation during orthodontic relapse, representing a biologic strategy for improving postorthodontic stability.