Do hybrid arch bar screws pose a risk to the dentition?

Abstract

Objective Hybrid arch bars have become popular alternatives to traditional Erich arch bars for use in craniomaxillofacial surgery. They offer the benefit of decreased time for application, reduced risk of sharps exposure to healthcare personnel, and decreased risk of compromised periodontal health. However, it has not been established if they pose a significant risk to the dentition. Damage to the teeth, such as violation of the pulpal canal or root fracture, can lead to clinically significant sequelae. The purpose of the study was to examine if the screws contact or violate the tooth structure during placement. Study Design A retrospective radiographic review of 50 patients treated with Stryker SMARTLock Hybrid Maxillomandibular fixation system at University Medical Center Hospital in New Orleans, from January 2018 to August 2018, was conducted. Postoperative axial slices of computed tomography (CT) scans were examined for screw position relative to the adjacent tooth roots. Patients were excluded if they were fully edentulous, were incarcerated, or did not have arch bars applied to both arches. Variables examined were screw violation of the periodontal ligament, gross disruption of tooth root dentin, pulpal violation, and root fracture. The location of the tooth injured with regard to the maxilla versus the mandible and the anterior, premolar, or molar dentition was also examined. Statistical analysis was performed with unpaired t test and 1-wayanalysis of variance with Tukey's post hoc test. Results Fifty patients were analyzed, for a total of 507 screws in 100 arches with 1340 teeth present. Overall, 31.49% of teeth had contact or injury with the screws, with screw violation of the periodontal ligament (7.39%), dentin (19.78%), and pulp (3.81%) and root fracture (0.45%). There was a significantly higher incidence of root fracture in the mandible (N = 5) versus maxilla (N = 1) (P Conclusions Hybrid arch bars offer many benefits to the surgeon, but there is no risk of the screw contacting or violating the tooth structure. There is an increased risk to the anterior dentition and the maxillary dentition. The mandibular teeth are also more likely to experience root fracture compared with the maxillary teeth. The hybrid arch bars should be applied with consideration to patient anatomy and tooth position to prevent injury to the tooth roots.