Eduardo Espinar-Escalona1, Luis-Alberto Bravo-Gonzalez2, Marta Pegueroles3, Francisco Javier Gil4. 1. Department of Stomatology, School of Dentistry, University of Seville, C/Avicena s/n, 41009, Seville, Spain. 2. Teaching Unit of Orthodontics, School of Dentistry, University of Murcia, Hospital Morales Meseguer, 2nd floor, Avda. Marqués de los Vélez s/n, 30008, Murcia, Spain. 3. Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering (ETSEIB), Technical University of Catalonia (UPC), Av. Diagonal 647, 08028, Barcelona, Spain. marta.pegueroles@upc.edu. 4. Biomaterials, Biomechanics and Tissue Engineering Group, Department of Materials Science and Metallurgical Engineering (ETSEIB), Technical University of Catalonia (UPC), Av. Diagonal 647, 08028, Barcelona, Spain.
Abstract
OBJECTIVES: Self-drilling orthodontic mini-implants can be used as temporary devices for orthodontic treatments. Our main goal was to evaluate surface characteristics, roughness and wettability, of surface modified mini-implants to increase their stability during orthodontic treatment without inducing bone fracture and tissue destruction during unscrewing. MATERIALS AND METHODS: Modified mini-implants by acid etching, grit-blasting and its combination were implanted in 20 New Zealand rabbits during 10 weeks. After that, the bone-to-implant (BIC) parameter was determined and the torque during unscrewing was measured. The surface characteristics, roughness and wettability, were also measured, onto modified Ti c.p. discs. RESULTS: Acid-etched mini-implants (R a ≈ 1.7 μm, contact angle (CA) ≈ 66°) significantly improved the bone-to-implant parameter, 26 %, compared to as-machined mini-implants (R a ≈ 0.3 μm, CA ≈ 68°, BIC = 19 %) due to its roughness. Moreover, this surface treatment did not modify torque during unscrewing due to their statistically similar wettability (p > 0.05). Surface treatments with higher roughness and hydrophobicity (R a ≈ 4.5 μm, CA ≈ 74°) lead to a greater BIC and to a higher removal torque during unscrewing, causing bone fracture, compared to as-machined mini-implants. CONCLUSIONS: Based on these in vivo findings, we conclude that acid-etching surface treatment can support temporary anchoring of titanium mini-implants. CLINICAL RELEVANCE: This treatment represents a step forward in the direction of reducing the time prior to mini-implant loading by increasing their stability during orthodontic treatment, without inducing bone fracture and tissue destruction during unscrewing.
OBJECTIVES: Self-drilling orthodontic mini-implants can be used as temporary devices for orthodontic treatments. Our main goal was to evaluate surface characteristics, roughness and wettability, of surface modified mini-implants to increase their stability during orthodontic treatment without inducing bone fracture and tissue destruction during unscrewing. MATERIALS AND METHODS: Modified mini-implants by acid etching, grit-blasting and its combination were implanted in 20 New Zealand rabbits during 10 weeks. After that, the bone-to-implant (BIC) parameter was determined and the torque during unscrewing was measured. The surface characteristics, roughness and wettability, were also measured, onto modified Ti c.p. discs. RESULTS: Acid-etched mini-implants (R a ≈ 1.7 μm, contact angle (CA) ≈ 66°) significantly improved the bone-to-implant parameter, 26 %, compared to as-machined mini-implants (R a ≈ 0.3 μm, CA ≈ 68°, BIC = 19 %) due to its roughness. Moreover, this surface treatment did not modify torque during unscrewing due to their statistically similar wettability (p > 0.05). Surface treatments with higher roughness and hydrophobicity (R a ≈ 4.5 μm, CA ≈ 74°) lead to a greater BIC and to a higher removal torque during unscrewing, causing bone fracture, compared to as-machined mini-implants. CONCLUSIONS: Based on these in vivo findings, we conclude that acid-etching surface treatment can support temporary anchoring of titanium mini-implants. CLINICAL RELEVANCE: This treatment represents a step forward in the direction of reducing the time prior to mini-implant loading by increasing their stability during orthodontic treatment, without inducing bone fracture and tissue destruction during unscrewing.
Entities:
Keywords:
In vivo animal studies; Mini-implants; Osseointegration; Surface treatments; Torque
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