Discussion
In 1967, subapical osteotomy was first used by Taylor et al.to treat
anterior alveolar protrusion[1]. Anterior
maxillary osteotomy (AMO) was performed through the anterior maxillary
osteotomy to form tooth 13 to tooth 23 (or tooth 14 to tooth 24)
segments of the tooth-bone, including anterior nasal spine and anterior
osseous nasal floor. The tooth-bone segment was often retreated or moved
upward to correct maxillary anterior teeth and alveolar bone
deformities. However, the procedure adopted in our case was an
unconventional anterior maxillary osteotomy. The tooth 14-24 tooth-bone
segment was incised and moved forward and downward to improve the
patient’s Class III bone profile as well as to increase the mesiodistal
space of missing tooth 15 and 25.
In this case, anterior maxillary osteotomy and anterior displacement can
greatly simplify the surgical approach, increase the mesiodistal
distance of the missing tooth area, provide enough space for implant
restoration, and achieve good aesthetic and functional effects. In our
case, the anterior maxillary osteotomy was performed with a labial
vestibular incision. Therefore, The blood supply of free tooth-bone mass
was mainly provided by the palatal periosteum, and the palatine
periosteum was relatively compact, so the bone mass was moved forward in
a limited range. After operation, the osteotomy block healed well and
the corresponding teeth were free of pain and loosening. The bone and
facial shape of the patient was improved effectively. The coordination
degree of the upper and lower arches, the mismatch of the midline and
the measurement parameters of the lateral position of the skull were
obviously improved and reached the normal level basically(Fig.8).
During 3 years of follow-up, the therapeutic effect was stable.
At present, autologous bone graft was a common method to solve serious
bone defects and it was characterized by good bone guidance, no immune
rejection, good induction of osteoblast differentiation and new bone
formation[2]. However, its disadvantage lied in
opening up a secondary operation area, which can easily lead to
secondary injury and complications in the site of bone extraction, and
bone resorption may sometimes occur after bone
grafting[3]. In this case, the removed cortical
bone fragments, which were obtained by sagittal split ramus osteotomy,
were placed in tooth 15 and tooth 25 osteotomy area. After one year of
follow-up, we observed the ideal vertical bone height of 16 mm and the
mesiodistal distance of 7mm for both tooth 15 and 25 area. However, the
absorption of the lip and tongue of bone tissue was more obvious (3mm
for both tooth 15 and 25 area). It is attributed to the fact that only
limited autogenous bone graft is used in the area of bone graft, no
excessive bone graft is performed, and the barrier membrane is not
covered by GBR at the same time, and the muscle tension of the buccal
region in the region of bone graft is greater after
operation[4].
This patient was a complex case with maxillofacial deformity with
congenital missing teeth and insufficient implant space which affected
the facial appearance and masticatory function. The combined application
of orthodontic and orthognathic surgery can solve the Angle III bone
facial shape of patients. Meanwhile, the modified orthognathic surgery
method increased the mesiodistal space of the missing tooth area and
reduced the difficulty of implant repair. In this case,
multidisciplinary participation and cooperation resulted in a marked
improvement in the patient’s facial appearance and occlusion(Fig.9)
Through the development of this case, we believe that for the complex
skeletal malocclusion cases which needed implant repair, it was
necessary to conduct multidisciplinary consultation before operation,
and to establish individualized treatment for patients, in order to
achieve the best repair effect.