Every year, thousands of drivers are either killed or injured due to motor vehicle accidents. The U.S. National Highway Traffic Safety Administration report indicated that in 2009, The national number of drivers killed in car accidents is 24,474,000 and injured 2,011,000 others.1 According to the 2014 report of the National Trauma Data Bank, motor vehicle accidents account for almost a third (27%) of all injuries reported by participating hospitals.2 Maxillofacial trauma and the accompanied teeth loss pose as a challenge for practitioners in treatment and restoration of esthetics and function.
The purpose of this case report is to present a case that was managed by an All-on-Four concept prosthesis after multiple teeth loss due to trauma.
Age and Sex: 18 yo female.
Medical History: Healthy individual.
PDH: Motor vehicle accident when she was 9 years old resulted in bilateral subcondylar fractures with loss of most of mandibular teeth. She has had a mandibular reconstructive surgery and intraloral skin autograft from the thigh. She has an acrylic RPD primarily for esthetic purposes.
CC:”I would like to replace my missing teeth with a fixed denture”.
Healthy, 18 yo female who was in a motor vehicle accident at 9 years of age.
Missing mandibular teeth 1, 16, 17-21, 24-29 and 32 due to accident trauma.
Generalized mandibular bony defect with horizontal bone loss, healed fractured mandible with portions of bone plate present.
Questionable prognosis of 22,23
1- Ext 22,23 and alveoloplasty, implant overdenture with attachments.
2- Four-implant bridge on mandibular right and mandibular left.
3- Ext 22,23 and alveoloplasty and 4 implant placements, 2 axial anterior , 2 tilted posterior
(All-on-four concept) prosthesis.
2- Do nothing (Existing RPD).
Discussion and Conclusion:
Restoring dentition due to trauma can be very challenging. All-on-Four concept prosthesis is a predictable method to restore function, esthetics and vertical dimension in such cases. Malo in 2003 reported this surgical approach to manage completely edentulous mandibles utilizing four root form implants placed in strategic locations, two axial anterior and two tilted posterior implants. The two axial implants provide anterior support for the future prosthesis and the two posterior tilted implants provide posterior support. To correct implant trajectory, angulated multi-unit abutments are used and can be set at 0o, 17o, or 300. Angulation of the abutments can be chosen so that the prosthetic screw-access holes are in an occlusal or lingual direction.3
Tilting the two posterior implants distally, anterior to the mental foramina serves several purposes; It allows the use of longer implants to provide better implant anchorage by increasing surface area for more bone to implant contact, shorten future cantilever on prosthesis, and increase the anterior-posterior spread of implants allowing for the use of up to twelve teeth, all of which improve overall prosthesis prognosis.3 Furthermore, there is a biomechanical advantage in utilizing splinted tilted distal implants with cross-arch stabilization as opposed to axial implants supporting distal cantilever units when comparing coronal stress.4 By not connecting implants from posterior of the mental foramen of one side to the other, the chance of stress shielding or phantom pain is reduced upon jaw opening.
In another study conducted by Malo in 2011 evaluating the long term outcome of such concept, high success rates of 98.1% at 5 years and 94.8% up to 10 years were reported and a low rate of marginal bone resorption was demonstrated.5 Furthermore, immediate loading of implant supported complete mandibular prosthesis was also documented in the literature with high success rates ranging from 97.5% to 100%. 6, 7, 8
1. Traffic Safety Facts 2012: A Compilation of Motor Vehicle Crash Data from the Fatality Analysis Reporting System and the General Estimates System. Washington, D.C.: National Highway Traffic Safety Administration, National Center for Statistics and Analysis, 2013. Ser. 812032. 2014. Web. 12 May 2015.
2. "NTDB Reports and Publications." American College of Surgeons. N.p., 2014. Web. 12 May 2015.
3. Maló, Paulo, Bo Rangert, and Miguel Nobre. "“All‐on‐Four” Immediate‐Function Concept with Brånemark System® Implants for Completely Edentulous Mandibles: A Retrospective Clinical Study." Clinical implant dentistry and related research 5.s1 (2003): 2-9.
4. Zampelis, Antonios, Bo Rangert, and Lars Heijl. "Tilting of splinted implants for improved prosthodontic support: a two-dimensional finite element analysis." The Journal of prosthetic dentistry 97.6 (2007): S35-S43.
5. Maló, Paulo, et al. "A longitudinal study of the survival of All-on-4 implants in the mandible with up to 10 years of follow-up." The Journal of the American Dental Association 142.3 (2011): 310-320.
6. Esposito, Marco, et al. "Interventions for replacing missing teeth: different times for loading dental implants." The Cochrane Library (2013).
7. Wang, Nai-Huei. "Ten-year results for Brånemark implants immediately loaded with fixed prostheses at implant placement." Int J Oral Maxillofac Implants 12 (1997): 495-503.
8. Balshi, Thomas J., and Glenn J. Wolfinger. "Immediate loading of Branemark implants in edentulous mandibles: a preliminary report." Implant Dentistry 6.2 (1997): 83-92.