Anterior maxillary osteotomy: A technical note for superior repositioning: A bird wing segment.

AIM: The aim of this study is to evaluate the efficacy of a single piece bird wing osteotectomy segment during anterior maxillary osteotomy (AMO) markedly reduces the duration of the surgery by nearly one-half of the time during bone removal with the conventional method thereby reducing the kinking effect to the palatal pedicle and gives good perfusion to the anterior segment.
MATERIALS AND METHODS: This study was conducted at Karpaga Vinayaga Institute of Dental Sciences composing of 20 patients in which male: female ratio was 8:12, with a mean age of 25-30 years. This bird wing segment technique is performed following presurgical orthodontics under the guidance of clinical assessment of the gummy smile with an incisal show when the lip is at repose (vertical maxillary excess), especially for the calculated amount of superior repositioning. It is calculated by subtracting 2 mm from the total amount of an incisor show when the lip is at repose. The normal incisal show when the lip is at repose is 2 mm. After conventional primary AMO cut was performed, the precise calculated.
RESULTS: All our cases were tested positive for pulp vitality, no relapse, and minimal edema and with no changes in the bite or dentoalveolar relation followed until 1 year postoperatively indicating a good perfusion to the anterior segment and all the patients were satisfied esthetically and free of complaints.
CONCLUSION: This simple technique allows the precise amount of calculated bone removal in a single piece from the nasal floor markedly reduces the duration of the surgery by nearly one-half of the time during bone removal with the conventional method there by reducing the kinking effect to the palatal pedicle and maintains good perfusion.

The anterior maxillary osteotomy (AMO) is employed primarily to reposition the anterior dento-osseous segment posteriorly. It is also used to move the segment superiorly or inferiorly as indicated. The first reported anterior segmental maxillary osteotomy was performed in 1921 by Cohn-Stock,[1] wherein a wedge of palatal bone was removed through transverse palatal incision and the anterior maxillary segment was retracted through elastic force. Several approaches for AMO has been advocated like Wassmund's[2] technique introduced in 1927, Wundere's[3] technique in 1963 and Cupar's technique in 1954 is the most preferred approach by many surgeons as it allows access for bone removal under direct visualization through the nasal floor. The bone from the lateral, superior, and posterior palatal surfaces are removed in slice until the premaxilla segment is placed in predetermined position as indicated by prefabricated splint. This maneuvering of bone removal by a trial and error method increases the operating time, leading to prolonged kinking on the palatal pedicle with resultant compromise to the vascularity of the anterior segment.

This bird wing segment technique is a simple procedure, which allows the precise amount of calculated bone removal in a single piece from the nasal floor markedly reduces the duration of the surgery by nearly one-half of the time during bone removal with the conventional method there by reducing the kinking effect to the palatal pedicle and maintains good perfusion to the osteotomy segment.

Materials and Methods

Materials

Study was conducted at Karpaga Vinayaga Institute of Dental Sciences composing of 20 patients in which male: female ratio is 8:12, with a mean age of 25-30 years. All patients were involved in presurgical orthodontics and the patients who have a gummy smile with the incisal show more than 8 mm when the lip is at repose (rest position) were involved in the study and also the patients:

Who wants the immediate esthetic improvement due to age bar for marriage in India, especially females nearly 30 years)

Who were not satisfied with the orthodontic treatment and insisted for surgical correction and also if they are fit for it

Who were having edentulous posteriors

Who were not indicated for Lefort-I osteotomy (Anemic or due to expecting posterior open bite or going for extensive surgery like three piece Lefort-I osteotomy or need for adjunct mandibular sub-apical osteotomy).

Methods

This bird wing segment technique is performed following presurgical orthodontics[4] under the guidance of clinical assessment of the gummy smile with an incisal show when the lip is at repose (vertical maxillary excess), especially for the calculated amount of superior repositioning. It is calculated by subtracting 2 mm from the total amount of an incisor show when the lip is at repose. The normal incisal show when the lip is at repose is 2 mm.[5] After conventional primary AMO cut was performed, the precise calculated height of bone is removed just 5 mm above the root apices, from the anterior nasal spine, nasal floor, and the pyriform rim in a single bird wing shape segment and fixed with 2-hole plate one on either side of the pyriform rim.

For example, [Figure 1] in a case where the incisal show is revealed as 10 mm when the lip is at repose, whereas the preferred amount of an incisal show is only 2 mm. This is achieved by superior repositioning of the premaxilla by 8 mm [Figure 2]. The clinically calculated 8 mm [Figure 3] to superiorly repositioning of the dentoalveolar segment, in a predetermined position with perfect alignment to the basal bone in end-to-end contact thereby providing maximum stability with minimum hardware of 2-hole plate one on either side of the pyriform rim [Figure 4].

Figure 1

10 mm of incisal show when lip is at repose

Figure 2

Osteotomy cut of 8 mm for superior repositioning of premaxilla

Figure 3

Single piece of ‘Bird-Wing’ like osteotomized segment

Figure 4

Stabilization with 2-hole plate in pyriform rim of both sides

Results

All our cases were tested positive for pulp vitality, no relapse, and minimal edema and with no changes in the bite or dentoalveolar relation followed until 1 year postoperatively indicating a good perfusion to the anterior segment and all the patients were satisfied esthetically and free of complaints.

Conclusion

This simple technique allows the precise amount of calculated bone removal in a single piece from the nasal floor to superiorly repositioning of the dentoalveolar segment in a predetermined position with perfect alignment to the basal bone in end-to-end contact thereby providing maximum stability with minimum hardware of 2-hole plate one on either side of the pyriform rim markedly reduces the duration of the surgery by nearly one-half of the time during bone removal with the conventional method there by reducing the kinking effect to the palatal pedicle and maintains good vascularity.