Contact with Root

31.49%

Dentin7.39%

Pulpal3.81%

Root Fracture

0.45%

No contact56.86%

Do Hybrid Arch Bar Screws Pose a Risk to the Dentition?

Danielle Wilt, DMD, MD, Chris Kim, DMD, MSE, Dane St. John, DMD, MD

Hybrid arch bars have become popular alternatives to traditional Erich arch bars for use in craniomaxillofacialsurgery. They offer the benefit of decreased time for application, reduced risk of sharps exposure to healthcare personal, 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 sequela. The purpose of the study was to examine if the screws contact or violate the tooth structure during placement.

Method

Conclusions

Result- Retrospective radiographic review of 50 patients- Stryker SMARTLock Hybrid Maxillomandibular fixation system at

University Medical Center Hospital in New Orleans from January 2018 to August 2018.

- Number of screws varies by practitioner, fracture pattern or anatomy

- Typically 5 screws / arch at our institution- Post-operative axial slices of CT scans were examined

- Screw contact with root vs dentin injury vs pulp injuryvs root fracture

- Exclusion criteria: - fully edentulous, incarcerated, not having arch bars applied to

both arches- Variables examined:

- screw violation of the periodontal ligament- gross disruption of tooth root dentin- pulpal violation- root fracture

- Location of root injury evaluated: - maxilla vs mandible- anterior vs premolar vs molar

- Statistical analysis: - paired t-test, one-way ANOVA with Tukey post hoc test

Figure 4. (A) contact with root, (B) dentin injury, (C) pulp injury, (D) root fracture, (E) root fracture

- 50 patients, 100 arches, 507 screws, 1340 teeth- Average 5 screws/ arch- Average 13 – 15 teeth/ arch- Graph showing percentage of number of teeth affected by screws- Certain tooth locations had significantly increased risk of contact or

violation of tooth root structure- Tooth injury: Mandible (4.74 ± 1.64), Maxilla (3.68 ± 1.63)- Root fracture: Mandible (5), Maxilla (1)- Location: Anterior (13.7%), Premolar (8.0%), Molar (9.8%)

- Hybrid arch bars offer many benefits to surgeons, but they can penetrate tooth roots and cause pulpal injury or root fractures

- Awareness of screw positioning and tooth anatomy- Limiting number of screws and maximizing placement in

edentulous section

Introduction

Figure 3. Stryker hybrid arch bars

Figure 2. Erich arch bars

Figure 1. Mandible fractures treated with hybrid arch bars and internal fixation

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