title: In vitro evaluation of conventional and locking miniplate/screw systems for the treatment of mandibular angle fractures.
abstract: This in vitro study evaluated the influence of the type of miniplate and the number of screws installed in the proximal and distal segments on the stability and resistance of Champy's osteosynthesis in mandibular angle fractures. Sixty polyurethane hemimandibles with bone-like consistency were randomly assigned to four groups (n=15) and sectioned in the mandibular angle region to simulate fracture. The bone segments were fixed by different osteosynthesis methods using 2.0 mm miniplates and 2.0 mm × 6 mm monocortical screws. In groups 1 and 2, two conventional (G1) or locking (G2) screws were installed in each bone segment using a conventional (G1) or a locking (G2) straight miniplate; in groups 3 and 4, three conventional (G3) or locking (G4) screws were installed in the proximal segment and four conventional (G3) or locking (G4) screws were installed in the distal segment using a conventional (G3) or a locking (G4) seven-hole straight miniplate. The hemimandibles were loaded in compressive strength until a 4mm displacement occurred between the segments, vertically or horizontally. Locking plate/screw systems provided significantly greater resistance to displacement than conventional ones (p<.01). Locking miniplates offered more resistance than conventional miniplates. Long locking miniplates provided greater stability than short ones.
authors.affiliation: Department of Maxillofacial Surgery and Traumatology, University of Sagrado Coração, Bauru, Brazil. paulodomingos@iocp.com.br
authors.forename: P D
authors.initials: PD
authors.lastname: Ribeiro-Junior
authors.forename: O
authors.initials: O
authors.lastname: Magro-Filho
authors.forename: K A
authors.initials: KA
authors.lastname: Shastri
authors.forename: M B
authors.initials: MB
authors.lastname: Papageorge
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D019245:Compressive Strength; D003799:Dental Stress Analysis; D004867:Equipment Design; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D008337:Mandibular Fractures / Q000601:surgery*; D003765:Models, Dental