title: Roughness and wettability effect on histological and mechanical response of self-drilling orthodontic mini-implants.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Stomatology, School of Dentistry, University of Seville, C/Avicena s/n, 41009, Seville, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Espinar-Escalona
authors.affiliation: 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.
authors.forename: Luis-Alberto
authors.initials: LA
authors.lastname: Bravo-Gonzalez
authors.affiliation: 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.
authors.forename: Marta
authors.initials: M
authors.lastname: Pegueroles
authors.affiliation: 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.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Gil
mesh_terms: D000134:Acid Etching, Dental; D000818:Animals; D001696:Biomechanical Phenomena; D001860:Bone Plates; D000069343:Bone-Implant Interface; D015921:Dental Implants; D003775:Dental Polishing; D020878:Device Removal; D005269:Femur / Q000601:surgery*; D020007:Implants, Experimental; D008422:Materials Testing; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D011817:Rabbits; D013499:Surface Properties; D014025:Titanium; D019415:Torque; D017155:Wettability
chemical_list: D015921:Dental Implants; D014025:Titanium
keywords: In vivo animal studies; Mini-implants; Osseointegration; Surface treatments; Torque