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Arch-bars, Leonard Buttons and IMF Screws are used to support and stabilise fractured jaws, both stabilising the jaw and the opposing jaw.

With elastics between the upper and lower jaw, it is hoped that the teeth and the way they are aligned and bite together will also correct.

Inter-Maxillary Fixation (IMF) or Mandibulo-Maxillary Fixation (MMF) is the concept of providing stabilisation to the jaws by binding the upper & lower dental occlusal arches (ie how the teeth bite together) to one another.

The most important goal in the treatment of any fracture of the maxilla (upper jaw) or mandible (lower jaw) is to re-establish the patient’s pre-injury dental occlusion (ie how the teeth bite together).  IMF allows the surgeon to set & secure proper occlusion.

For some fractures, reduction and stabilisation with IMF provides adequate treatment without internal fixation and is maintained long enough to allow the fracture (or fractures) to heal.

For many (if not most) jaw fractures, IMF is a crucial step in the process of Open Reduction and Internal Fixation (ORIF).  It is critical to understand that success and failure in fracture treatment are defined by occlusal outcome.

An apparent anatomic reduction can result in occlusal imperfection if proper steps are not taken to ensure correct occlusion first.

Over time, many methods have been employed to provide IMF (2 are covered here).  The “first and last” principle for IMF is emphasised for cases treated by ORIF: IMF is applied first to secure occlusion; it is released last to check occlusion.

Archbars_Inter-Maxillary_Fixation
Photos of Archbars that have been wired to teeth. Elastics or wires are used to bring the archbars (and hence, teeth and jaws) together.
Photos of Archbars that have been wired to teeth. Elastics or wires are used to bring the archbars (and hence, teeth and jaws) together.

Removal of the archbars, Leonard buttons or IMF screws is often done without the use of anaesthesia.  This is so, as to numb up the mouth would entail multiple injections for what benefit?  The procedure is quick and though can be slightly sore at the time, this settles quickly.

The archbars are wired to the teeth to keep them in place.  This has the knock-on effects of:

  • Staining to teeth
  • Early decay around the necks of the teeth
  • Bleeding that is easily provoked with tooth brushing of bleeding from the gums
  • (Marked) Gum recession leading to dentine sensitivity to hot and cold
  • Extrusion of the teeth, with the occlusion needing time to bed in

After the archbars have been removed, you may need to take painkillers for the following 24 – 36 hours, use antiseptic mouthwashes until the gums appear healthy, and when circumstances allow, maintain good oral hygiene.

Inter_Maxillary_Fixation_Screw

Useful Articles & Websites

Natl J Maxillofac Surg 2010.  A new & easy technique for maxillomandibular fixation

JOMS 2010.  IMF Screw – An Ideal Intermaxillary Fixation Device During Open Reduction of Mandibular Fracture

JOMS 2011.  Are Maxillomandibular Fixation Screws a Better Option Than Erich Arch Bars in Achieving Maxillomandibular Fixation?  A Randomized Clinical Study

JOMS 2011.  Complications Using Intermaxillary Fixation Screws

Natl J Maxillofac Surg 2011.  A Questionnaire Survey on Postoperative Intermaxillary Fixation in Mandibular Trauma – Is Its Use Based on Evidence?

Dental Traumatology 2012.  A Retrospective Evaluation of Iatrogenic Dental Root Damage with Predrilled vs Drill-Free Bone Anchor Screws for Intermaxillary Fixation

JOMS 2013.  Are Arch Bars Necessary for Maxillomandibular Fixation? – a Paradigm Shift

Ann Pak Inst Med Sci 2014.  Immediate Post-Operative Complications in the Treatment of Mandibular Fractures at Angle Region by Rigid Fixation Using Mini Bone Plates With or Without Intermaxillary Fixation

Ann Maxillofac Surg 2016.  Intermaxillary Fixation Screws vs Erich Arch Bars in Mandibular Fractures – A Comparative Study & Review of Literature

Ann Plast Surg 2016.  Maxillomandibular Fixation by Plastic Surgeons – Cost Analysis & Utilization of Resources

Biomed Pharmacol J 2017.  Comparison of Arch Bar, Eyelets & Transmucosal Screws for Maxillo Mandibular Fixation in Jaw Fracture

Int J Rec Sci Res 2017.  IMF Screws – An Alternative to Archbars

Natl J Maxillofac Surg 2018.  Evaluation of Efficacy of Intermaxillary Fixation Screws versus Modified Arch Bar for Intermaxillary Fixation

Professional Med J 2019.  Mandibular Fracture Management – Comparison of Efficacy of Maxillomandibular Fixation of Screws vs Erich Arch Bar