title: Biomechanical evaluation of different types of rigid internal fixation techniques for subcondylar fractures.
abstract: OBJECTIVE
  The aim of this study was to evaluate the biomechanical stability of various internal fixation systems for subcondylar fractures.
  
  
  METHODS
  Eighteen identical synthetic mandibles were used. Left condylar processes were cut to mimic perpendicular subcondylar fracture and right sides were mimicked oblique subcondylar fracture. The fixation systems used included single 4-hole mini adaptation plate, double fixation with the same plates, single 4-hole mini dynamic compression plate (DCP), Eckelt lag screw system, Wurzburg lag screw plate system and double 4-hole biodegradable miniplates made of poly L-lactide (PLLA). In oblique fractures, one of the screws fixing plates was used bicortically through bone fragments. The loading vector simulated physiologic forces to the condyle on biting with servohydraulic testing machine until failure was reached. Load-displacement curve, maximum load for failure, and stiffness were measured.
  
  
  RESULTS
  In perpendicular fracture, double adaptation plate showed the highest level of tolerance load followed by Eckelt lag and double PLLA plate. In stiffness, double adaptation plate and Eckelt lag screw showed higher level of stiffness, whereas double PLLA was almost at the same level of single DCP. In oblique fracture, double adaptation plate showed the highest strength.
  
  
  CONCLUSIONS
  In this laboratory setting, double adaptation plates fixation proved to have superior biomechanical stability in both fracture conditions. Eckelt lag screw showed good stability in the perpendicular fracture, however, it was weak in the oblique fracture.
authors.affiliation: Associate Professor, First Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu, Japan. tominaga@kyu-dent.ac.jp
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Tominaga
authors.forename: Manabu
authors.initials: M
authors.lastname: Habu
authors.forename: Amit
authors.initials: A
authors.lastname: Khanal
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Mimori
authors.forename: Izumi
authors.initials: I
authors.lastname: Yoshioka
authors.forename: Jinichi
authors.initials: J
authors.lastname: Fukuda
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D003799:Dental Stress Analysis / Q000379:methods; D004867:Equipment Design; D004868:Equipment Failure; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D019248:Jaw Fixation Techniques / Q000295:instrumentation*; D019344:Lactic Acid; D008337:Mandibular Fractures / Q000601:surgery*; D008904:Miniaturization; D008953:Models, Anatomic; D011091:Polyesters; D011108:Polymers
chemical_list: D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)