Three-year Follow up of Skeletal and Occlusal Stability After Bilateral Sagittal Split Osteotomy Combined With All-on-4 Implants Placement in a Patient With Mandibular Asymmetry and a Collapsed Occlusion

Statement of the problem: With the spread of the dental implants, we often have opportunities of seeing patients with jaw deformities, who hope for implant treatment.   This report describes a 3-year follow up case of skeletal and occlusal stability after Bilateral Sagittal Split Osteotomy (BSSO) with simultaneous implants placement using All-on-4 method.

Materials and methods:A 49-year-old male with mandibular asymmetry and a collapsed occlusion caused by severe periodontal disease was refered to our department with the hopes of receiving dental implant treatment. All of 15 remaining teeth were mobile in three direction and showed a cross bite with a left side shift of the mandibular alveolar ridge. Surgical and prosthetic treatment was planned so that all teeth would be removed and replaced with All-on-4 implants. BSSO was performed for correct positioning of the mandible. The patient underwent BSSO after immediately receiving a loaded fixed bi-maxillary prosthesis based on All-on-4 method. Inter maxillary traction with elastics was done 2 months after the surgical operation.

Methods of the analysis: We measured the mandibular midline changes after the surgical operation by Menton deviation angle (Horizontal deviation angle of facial midline to Crista galli-Menton) and distance on postero-anterior cephalograms.   

Results: Menton deviation angle and distance were 4.1°and 10.1mm before the surgical operation. During 6-month follow up, the midline of occlusion relapsed 2.0mm to left side, Menton deviation angle and distance increased from 2.1°and 4.9mm on  next week after the surgical operation to 2.5°and 5.7mm, respectively. A final prosthesis was fabricated 10 months after the surgical operation. The 3-year follow up data showed that the occlusion did not relapse except the beginning 6 months, while Menton deviation angle and distance further increased to 3.1°and 7.1mm.  

Conclusion: This report suggests that BSSO with simultaneous implants placement using All-on-4 method might be useful for patients with mandibular asymmetry and a collapsed occlusion.

References:

1: Nishida E, Tamura T, Tonogi M, et al: Evaluation of postoperative frontal face in facial asymmetry cases following sagittal splitting ramus osteotomy. Jpn J Jaw Deform 23: 209, 2013

2: Grandi T, Guazzi P, Samarani T, et al: Immediate loading of four (all-on-4) post-extractive implants supporting mandibular cross-arch fixed prosthesis: 18-month follow up from a multicentre prospective cohort study. Eur J Oral implantol 5: 277, 2012