study the use of simple and effective methods for the treatment of mandibular fractures.

Disruption of the endosteal and periosteal blood supply occurs with the initial trauma, and maintaining adequate blood supply to the fracture site is essential for healing. Hunter described the 4 classic stages of natural bone repair: inflammation, soft callus, hard callus, and remodeling. The inflammation stage begins soon after injury and appears clinically as swelling, pain, erythema, and heat. Disrupted local vascular supply at the injured site creates a hematoma and prompts the migration of inflammatory cells, which stimulate angiogenesis and cell proliferation. After the initial inflammatory phase, the soft callus stage begins with an infiltration of fibrous tissue and chondroblasts surrounding the fracture site. The replacement of hematoma by this structural network adds stability to the fracture site.

Soft callus is then converted into rigid bone, the hard callus stage, by enchondral ossification and intramembranous bone formation. Once the fracture has united, the process of remodeling begins. Fibrous bone is eventually replaced by lamellar bone. Although this process has been called secondary bone union or indirect fracture repair, it is the natural and expected way fractures heal. Fractures with less than an anatomic reduction and less rigid fixation (ie, those with large gaps and low strain via external fixator, casting, and intramedullary [IM] nailing) heal with callous formation or secondary healing with progression through several different tissue types and eventual remodeling.

Anatomic reduction and absolute stabilization of a fracture by internal fixation alter the biology of fracture healing by diminishing strain (elongation force) on the healing tissue at the fracture site. Absolute stability with no fracture gap (eg, via ORIF using interfragmental compression and plating) presents a low strain and results in primary healing (cutting cone) without the production of callus. In this model, cutter heads of the osteons reach the fracture and cross it where bone-to-bone contact exists. This produces union by interdigitation of these newly formed osteons bridging the gap. The small gaps between fragments fill with membranous bone, which remodels into cortical bone as long as the strain applied to these tissues does not cause excessive disruption and fibrous tissue develops (nonunion). This method of bone healing is known as direct bone healing or primary bone union. Essentially, the process of bone remodeling allows bone to respond to the stresses to which it is exposed.

Based on the mechanical milieu of the fracture as dictated by the surgeon’s choice of internal fixation and the fracture pattern, 2 patterns of stability can result that determine the type of bone healing that will occur. Absolute stability (ie, no motion between fracture fragments) results in direct or primary bone healing (remodeling). Relative stability (ie, a certain amount of fragment motion) heals with secondary or indirect bone union.