Dental Implant Restoration of a Mandibular Gunshot Injury: A Case Report

Firearms are typically categorized by the velocity of the projectile. Rifles are high-velocity (2000 ft/s), and handguns are low-velocity (less than 2000 ft/s). The greater the muzzle velocity, the greater the tissue damage on impact. Also, the amount of kinetic energy the projectile possesses at the time of impact is much more important than the bullet’s muzzle.¹  Other concepts regarding the science of ballistics are beyond the scope of this article but certainly have an effect on the degree of tissue injury from a gunshot wound.

When a gunshot occurs, the kinetic energy from the bullet is transferred to the tissues in its path. The maxillofacial region, which includes the face, jaw, and associated structures, is particularly vulnerable due to its complex anatomy and proximity to vital structures. The impact can cause extensive damage to both soft and hard tissues, leading to a range of injuries. Higher bullet velocities increase kinetic energy, leading to more extensive tissue damage.

A gunshot injury can be classified into 1 of 3 categories: penetrating, perforating, and avulsive. The penetrating injury occurs when a bullet enters but does not exit the victim. A perforating injury has both entry and exit wounds. An avulsive wound results when the bullet enters the body and exits with substantial loss of tissue.² 

High-energy, avulsive injuries result in soft tissue loss and subsequent devascularization of bone.³  The bullet’s kinetic energy is not the only factor causing damage. The bullet’s deformation capability, fragmentation, and resistance to deformation exhibited by involved tissue are accompanying factors.³  This damage may include fractures of facial bones, disruption of soft tissue structures, and damage to blood vessels and nerves. When bullet impact is made with bones and teeth, fragments may act as secondary projectiles, causing additional damage.

Gunshot injuries to the maxillofacial region, if not fatal, can have significant and often devastating consequences, both functionally and esthetically. The severity of these injuries depends on various factors, including the type of firearm, the velocity of the bullet, and the specific location of impact.

The face is a common site for these devastating wounds with injuries affecting the face and neck. In order, the specific sites most commonly affected are the mandible, maxilla, zygomatic region, eye socket, and nose.⁴  The consequences of gunshot injuries to the maxillofacial region can be profound. Functionally, patients may experience difficulties with speech, chewing, and breathing, depending on the extent and nature of the injuries. Esthetic consequences are also significant as these injuries can result in disfigurement and the loss of facial symmetry. Surgical reconstruction is indicated and is usually followed by maxillofacial prosthodontic reconstruction.

This case report describes an individual who was a victim of a gunshot injury to the maxillofacial region, specifically the posterior mandibular body, resulting in loss of teeth and bone volume and mandibular fracture. A description of mandibular stabilization, autogenous bone grafting, and bone regeneration is presented with final prosthodontic reconstruction and restoration of form and function.

A 52-year-old African American female presented to the postgraduate prosthodontics clinic of Nova Southeastern University College of Dental Medicine for evaluation and treatment. Her history was significant for a gunshot injury to the right face, specifically the posterior mandible, 11 years previous. She recounted the treatment she had received, which involved emergency care followed by surgical intervention for rehabilitation. The emergency medical treatment following the initial gunshot injury was at another regional hospital, and complete records were reviewed. It would have been nice to have photographs illustrating the original injury and treatment; however, these were not available, so they were not included in this paper. The original gunshot injury caused a comminuted right mandibular fracture with loss of mandibular teeth and bone mass, and consequently, a reconstruction plate was inserted for immediate stabilization. Following a brief hospital stay, the patient recovered from her initial injuries.

Nine months after the initial injuries, the patient presented to the Nova Southeastern University Department of Oral and Maxillofacial Surgery for consultation regarding mandibular rehabilitation and replacement of mandibular teeth. Informed consent was obtained for diagnostic and therapeutic procedures. The radiographic survey revealed a comminuted fracture of the right mandible, residual defects with missing bony sections of the right posterior mandibular body, and visible remnants of bullet fragments. A reconstruction plate was in place without evidence of hardware failure or loosening (Figure 1). It was determined that bone augmentation was needed to rehabilitate the mandibular teeth with any prosthodontic restoration.

A treatment plan was developed to debride the wound area with a concomitant iliac crest graft to the right mandibular body. Grafting large defects of the mandible may involve either vascularized or nonvascularized grafts. A vascularized bone graft is often indicated in defects where composite hard/soft tissue is required. Cases of smaller defects with no soft tissue requirement may be amenable to reconstruction with a nonvascularized bone graft.⁵  In this case, a nonvascularized bone graft was indicated and harvested from the iliac crest. This bone augmentation procedure was completed, and the patient was followed for approximately 1 year with a normal postoperative result.

The patient presented to the Postgraduate Prosthodontics Clinic at Nova Southeastern University approximately 10 years later. The patient reported no complaints regarding residual pain and no neurosensory deficit in the inferior alveolar or mental nerve distribution. The patient’s chief complaint was a desire to replace the mandibular right quadrant of teeth. There was no explanation for why the patient waited 10 years to consider dental reconstruction, and the subject was not pursued. The patient reported that no interim prosthesis had been worn during this entire time, and the patient did not report any problems except for difficulty in adequate mastication. The radiographic survey revealed a fully healed right mandible with adequate bone volume for implant placement (Figures 2 and 3). Clinical examination revealed healed oral mucosa overlying mandibular bone in the right posterior sextant (Figure 4). All mandibular teeth were missing from #25–#32 with alveolar bone height deficiency #26–#28. The patient had healthy natural teeth #19–#24 and a full complement of healthy, natural teeth in the maxilla, #3–#15 (Figures 4 and 5). After discussing different treatment options, the patient elected to have a fixed, implant-supported restoration as a permanent solution for tooth loss.

Diagnostic casts of the maxilla and mandible were made and articulated as usual. Diagnostic wax-up demonstrated that the final result would be amenable to a screw-retained, FP-3 fixed restoration that replaced both teeth and the alveolar process. A periapical preoperative cone-beam computerized tomography (CBCT) radiographic survey showed excellent bone regeneration, resulting in adequate quantity and quality of implant recipient bone. Considering this, a plan was formulated to place 4 implants as a foundation for mandibular restoration.

Full-thickness mucoperiosteal flaps were elevated with releasing incisions distal to tooth #24 and distal to the terminal implant position. The underlying bone was exposed; however, there was a significant amount of dense connective tissue in the mental nerve area, enveloping the mandible’s lateral and medial aspects (Figure 6). Because the patient had no neurosensory deficits of the inferior alveolar nerve and, thus, the mental nerve, it was decided not to incise this tissue to expose bone in the area of the mental nerve. Consequently, implants were placed anterior to this tissue and posterior to it in the areas of #26 and #29–#31. All implants placed were Dentsply EV 3.6 × 11 mm. Healing abutments were placed, and tissue was closed. Postoperative healing was uneventful, and the patient reported no neurosensory deficit.

After a 3-month osseointegration period, healing abutments were removed, and 1.5-mm straight multiunit abutments were placed (Figure 7). An abutment-level impression using polyvinyl siloxane material (Aquasil Ultra, Dentsply/Sirona, York, PA) was made, and implant analogs were attached to the impression copings. A silicone gingival mask (GI Mask, Coltene, Altstatten, Switzerland) was syringed around the multiunit abutments, and the master cast was poured in resin-modified gypsum (Resin Rock, WhipMix, Louisville, KY). This material was chosen due to its blend of synthetic resin and gypsum, which results in a smooth surface, increased resistance to abrasion, good dimensional stability, and low expansion.

The master cast was articulated using an occlusal rim, and the case was scanned using The Freedom HD Lab Scanner (DOF, Seol, Korea). A fixed, screw-retained prototype was designed using dental implant design software (Exocad Dental CAD, Imagine Technologies, Chantilly, VA) and milled in polymethylmethacrylate (PMMA). The PMMA prototype was delivered to the patient for a functional trial period. Approximately 1 month later, the patient returned for reevaluation and had no complaints. The final restoration was then milled in the Ivoclar PrograMill PM7 milling machine (Ivoclar, Schaan, Liechtenstein). The restorative material was a monolithic zirconium oxide (IPS emax ZirCAD, Ivoclar) composed of a blend of 3y-TZP and 5y-TZP zirconia. This material was chosen due to its excellent accuracy of fit and superior strength (Figures 8 and 9). The final restoration was delivered, and restorative screws were torqued to 15 Ncm. Access cylinders were filled with polytetrafluoroethylene material, and access openings were filled with composite resin (Figures 10 and 11). Final occlusal contacts were adjusted, composite restorations in access openings were polished, and no interferences were noted in excursive movements. The patient was followed up for additional periodic recall appointments and reported extreme satisfaction with the restorative result. At the recare visits, the occlusion was checked and found to be stable. Gingival health around the implant abutments was healthy, and dental implants showed no bone loss radiographically.

Surgical management of a gunshot injury to the maxillofacial region typically follows this sequence: (1) immediate stabilization in the anatomic position of existing bone and/or bone segments, (2) primary closure of existing soft tissue, (3) debridement procedures, and (4) definitive reconstruction of soft-tissue and bony defects.² 

Immediate stabilization of mandibular bony segments has improved recently with digital technology. Stereolithographic models can be generated from CBCT, whereupon custom, prebent reconstruction plates can be made with impressive precision.⁶  In this particular case, early fixation of the fractured mandible was done with a prebent fixation plate, together with wound debridement. As stated, photographs of the initial gunshot injury and treatment were not available and, therefore, are not included in this paper. After a 9-month healing period, the patient presented for definitive, follow-up treatment with the Department of Oral and Maxillofacial Surgery at Nova Southeastern University College of Dental Medicine.

When initial stabilization and debridement are completed and healing has been uneventful, the patient can be considered for autogenous bone augmentation. Typically, in a case such as this one, autogenous bone from the contralateral iliac crest is harvested to rebuild as much of the mandibular bone as possible. The literature reports highly successful results using autogenous bone grafted from the iliac crest, particularly in continuity defects up to 9 cm.⁵  This was the procedure performed in this case report.

When a complete healing of both the initial injury and the follow-up mandibular augmentation has taken place, consideration can be made for prosthodontic reconstruction of the dentition. Multiple factors must be taken into account when planning the fixed restoration. A digital or analog wax-up is critical for successful planning, just as in any complex restoration. This way, implants can be designed and restorative contours and occlusal aspects may be anticipated.

After appropriate planning, implants were placed, and osseointegration was achieved using the conventional, unloaded technique. Bone quality was optimal due to a meticulous bone-grafting procedure and an extended period of undisturbed healing.

Reconstruction of a posterior quadrant of teeth with monolithic 3y-5y zirconia in a screw-retained design provides a durable, esthetic, and functional fixed prosthesis. This case illustrates this type of success.

A gunshot wound to the posterior mandible was the initiating factor in this case report. An immediate stabilization procedure in conjunction with initial debridement was performed. After complete healing, a bone augmentation graft was performed using autogenous bone from the iliac crest. Implants were placed with uneventful healing, and a definitive, monolithic zirconia screw-retained prosthesis was fabricated to restore the lost natural teeth.

Maxillofacial gunshot injuries can result in significant destruction of facial bone volume as well as soft tissue deficiency. Jaw reconstruction with implant rehabilitation is challenging, but if managed in a multidisciplinary approach, it can be successful, rewarding, and greatly appreciated by the patient.

Both authors declare no conflict of interest or financial interest in any part of this article.