Radiodensitometric Assessment of the Effect of Pulsed Electromagnetic Field Stimulation Versus Low Intensity Laser Irradiation on Mandibular Fracture Repair: A Preliminary Clinical Trial

Purpose

Closed reduction of mandibular fractures usually entails a relatively long period of immobilization, with the subsequent delay of rehabilitation. Therefore, shorter immobilization period with various approaches to protect or enhance bone healing have been investigated. The aim of this study was to analyze the effects of pulsed electromagnetic field (PEMF) and low intensity laser irradiation (LILI) on the fracture healing process, through radiodensitometric assessment of the bone callus.

Patients and Methods

Eighteen patients with mandibular fractures at the tooth bearing area participated in this prospective study. They were treated by closed reduction using maxillo–mandibular fixation (MMF) and were consecutively assigned into 1 of 3 groups. In group A, the fracture sites were exposed to PEMF for 2 h daily for 12 days. In group B, the fracture sites were exposed to LILI on the tenth and twelfth postoperative days (2 sessions of 6 min per day 2 h apart). The fracture sites in group C acted as controls. MMF was maintained for 2 weeks in group A and 4 weeks in groups B and C. The bone fracture healing was evaluated clinically by investigating the union of the fractured segments and radiographically using computerized densitometry. The union of the fractured segments was tested by manual manipulation and the occlusion was assessed upon removal of MMF. Standardized digital panoramic radiographs were performed for each patient, immediately postoperatively as well as at 2 and 4 weeks. The digital images were manipulated using the IDRISI software. A rectangular area of 10 × 15 mm was drawn along the center of the fracture line. The obtained densitometry values were expressed in gray levels from 0 to 256. The collected data were then tabulated and statistically analyzed.

Results

After releasing the MMF, the bimanual mobility test of the fractured segments in all patients showed stability of the segments. The preinjury occlusion was maintained in all patients. The postoperative radiographs of all patients revealed good bony alignment of the bony segments. In all groups, comparison between the study intervals with respect to both means and changes percentages of the bone density values showed insignificant differences. At 2nd postoperative week, the mean bone density at the fracture sites decreased by 4.74, 6.6 and 27.89 % in groups A, B and C respectively. The period from the 2nd to the 4th postoperative weeks showed increase in the bone density by 1.49, 1.95 and 14.12 % in groups A, B and C respectively. Insignificant difference was found between the means of bone densities of group A and B throughout the study intervals. On the other hand, both groups showed insignificant difference with group C immediately postoperative and significant increase in bone density at the 2nd and 4th postoperative weeks.

Conclusions

Short period immobilization of mandibular fractures for 2 weeks supplemented with PEMF is recommended. Further studies are needed to evaluate the efficacy of LILI as a supplement to reduce the mandibular fracture immobilization period.