Case Study: Orthognathic Surgery for Maxillary Hypoplasia + Compromised Orthodontic Treatment

Case Study: Orthognathic Surgery for Maxillary Hypoplasia + Compromised Orthodontic Treatment

Case Study No. 2: Orthognathic Surgery for Maxillary Hypoplasia + Compromised Orthodontic Treatment

A complication of orthodontic treatment sometimes arises when anterior maxillary tooth position is compromised in an attempt to camouflage the need for Orthognathic Surgery. This scenario has become more and more common in the last few decades as orthodontists try to forgo the incorporation of Orthognathic Surgery in patients with combined dental and skeletal malocclusions.

Patients sometimes struggle to accept treatment plans that include jaw surgery. They reject treatment altogether when they can’t find simple answers to their questions about medical insurance coverage and cost of Orthognathic Surgery. Many times the orthodontist becomes frustrated when they become mired in a case they can’t finish because a skeletal deformity stands in their way. Camouflaging the misaligned jaw, compromising the final position of the teeth or compromising the final bite sometimes seems the only way out. Sometimes this strategy is “successful”. Mild mandibular asymmetries can be hidden, a minimally hypoplastic maxilla can be covered up by proclination of maxillary incisors, and mandibular retrognathia can be concealed by flaring mandibular incisors. While these compromises may not lead to immediate functional or stability problems, over the course of years or decades serious issues may arise. Such is this case.

The patient is a 48-year-old female who, as a young adult, underwent orthodontic treatment to resolve maxillary crowding and a palatally impacted canine. (Fig. 1)

No treatment was suggested for her skeletal mid-facial hypoplasia. After several years and several attempts at moving the right canine into position, it was lost and a particulate graft was done to prepare the site for an implant. The first fixture that was placed failed. The second implant successfully integrated but was positioned so apically to the adjacent teeth that it could not be restored. (Fig. 2) 

Complicating the situation, the patient began experiencing mobility in her anterior teeth. Her workup confirmed maxillary hypoplasia and her compromised orthodontic treatment, consisting of proclination of the maxillary incisors, canines and bicuspidsto obtain overjet, resulted in tooth mobility, and root resorption of # 7. (Fig. 3) 

Another orthodontic consult was obtained and, through a team approach, a treatment plan was formulated to correct the position of the anterior maxillary teeth and replace the missing right canine.

Our first step was to agree that the malocclusion would require Orthognathic Surgery. The workup by the orthodontist using a Sassouni analysis was confirmed with a G. William Arnett analysis and a work up using Andrew’s “Six Elements of Orofacial Harmony”. A multi-segmental LeFort I advancement was determined to be the best surgical procedure to return the anterior maxillary dentition to its proper position to the skeletal base.

Two hurdles had to be overcome:
1. Removing the implant and reconstructing the area with an autogenous bone graft so that an implant could be placed after the orthognathic surgery.
2. Obtaining space to allow for clockwise rotation of the premaxilla and repositioning of the anterior segment for the advancement of the entire maxilla to a Class I canine relationship.

Prior to orthodontics, the implant in the area of # 6 was removed and the area bone grafted using an enbloc bone grafting technique overlaying a particulate graft to fill the defect from the removal of the implant. A CBCT confirmed the success of the bone graft. (Fig. 4)

 

Progress model surgery confirmed the premaxilla could be rotated clockwise by extracting the maxillary 1st bicuspids and using the extraction spaces to pivot the premaxilla clockwise and rotate it down. The posterior segment was split and widened to correct the Curve and Wilson. (Fig. 5)

The posterior maxillary segments were then advanced to a Class I canine relationship and the extraction spaces closed. (Fig. 6)

A postoperativecephalometric x-ray confirmed the clockwise rotation of the anterior maxillary segment by 15 degrees. (Fig. 7) The patient is awaiting the placement of the titanium fixture in the area of # 6.

This case demonstrates the problem of tooth mobility and bone loss when anterior teeth are proclined and placed into functional occlusion. Flaring the teeth outside the limits of their skeletal base to camouflage a Class III or Pseudo-Class III skeletal relationship is sometimes a recipe for severe dental consequences. Treatment through a combined orthodontic and Orthognathic Surgical approach can be the solution. A pre-operative and post-operative smiling image demonstrates the aesthetic difference when anterior maxillary teeth are placed in their proper axial inclination. (Fig. 8)

 

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