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Subapical osteotomy to increase mandibular arch length
Subapical 0s teotomy to increase mandibular arch length William H. Bell, D.D.S.* Dallas,
Texas
0
rthodontic treatment of dentofacial deformities is frequently complicated by crowded and malaligned teeth which are tipped forward off their bony base. The purpose of treatment is to align and move the teeth into the best possible position over their skeletal base. To accomplish this by orthodontic measures alone, it is usually necessary to extract maxillary and mandibular premolars. With such treatment, however, occlusal harmony is frequently achieved at the expense of facial esthetics because the upper anterior teeth and lip are retracted. In addition, the treatment time may be increased. Planning Anterior mandibular subapical osteotomy offers an alternative method of managing selected malocclusions which are associated with minimal to moderate crowding. Persons with a Class II deep bite, dentoalveolar retrusion, normal chin prominence, and deep labiomental fold are potentially good candidates for such treatment. The mandibular anterior teeth are surgically repositioned anteriorly to increase arch length, facilitate postsurgical orthodontic treatment of crowded and malaligned teeth, and obviate the need for extractions. Additional soft-tissue facial support is gained from the advanced dento-osseous segment. The anterior mandibular alveolar segment is moved fotward the distance which, calculated from a Bolton analysis and diagnostic orthodontic setup, is necessary to align the teeth. Careful preoperative occlusal analysis and planning by the surgeon and the orthodontist are essential to select the appropriate interdental osteotomy site and determine the feasibility of the surgical plan. To date, vertical interdental osteotomies have been made only in the canine-lateral incisor or canine-first premolar interspaces. Mandibular
subapical
osteotomy-surgery
technique
For this procedure, the patient is usually placed under general nasoendotracheal anesthesia. When, however, only the incisor teeth are to be repositioned, the surgery is easily carried out with only local anesthesia. A local anesthetic agent with vasoconstrictor is infiltrated into the mental symphysis region for hemostasis. The incision for the anterior mandibular subapical osteotomy is designed to maintain circulation to the lingual and labial aspects of the mobilized dental osseous segment (Fig. 1). Anteriorly, the incision is made through the lower lip mucosa above the labial frenum, midway between the depth of *Associate Professor, The University of Texas Health Science -... ~_. ,.. .a.*..^ uy,6cLJ, CL;;,, F”, Cu~~;,Lfi -. ._..,,.. _. -.-. . .. . .l‘l_\..‘UIILLLI
276
OOG2-9416/78/0374-0276$01.00/O
Center, Department of Surgery, of Dixefxia: Dcfwktieb. 0
1978 The C.V.
Mosby Co.
Volume 74 Number 3
Subapical
osteotomy
277
Fig. 1. Anterior mandibular subapical osteotomy to increase mandibular arch length. A, Typical dental, skeletal, and facial features associated with mandibular deficiency and skeletal-type deep bite; mandible in centric relation and lips relaxed. Note lip incompetence, retroinclined maxillary incisors, retropositioned and crowded mandibular incisors, Class II, Division 2 malocclusion, and deep labiomentai fold. Plan of treatment: Mandibular subapical osteotomy without extraction of teeth to advance lower anterior teeth, increase arch length, and partially level mandibular arch; bilateral sagittal split ramus osteotomies to advance mandible into Class I canine and molar relation; alignment of maxillary arch by orthodontic treatment. Arrows indicate planned directional movements of teeth and dento-osseous segment. B, Mental symphysis degloved to facilitate horizontal and vertical osteotomies. C, Lingual mucoperiosteum undermined distal to mobilized segment to allow segment to be advanced; stippling indicates area of detached mucoperiosteum. D, Maxillary arch aligned by orthodontic treatment; segmental orthodontic appliances used in mandibular arch.
the labial vestibule and the vermilion border of the lower lip. The incision is carried laterally and posteriorly into the most lateral part of the buccal vestibule and terminated at least 1 cm. posterior to the planned vertical osteotomy site. In the premolar region, the initial incision is made through the mucosa only in order to obviate injury to superficial branches of the mental nerves. In the anterior region of the lower lip, the incision is carried sharply through the
278
ml
Am. J. Orrhod. September 1978
Fig. 1. (Cont’d). E, Repositioned mandible in intermaxillary fixation after surgical advancement to Class I occlusion; mandibular anterior teeth are aligned by retraction of anterior teeth into space by subapical osteotomy. F, Class I molar and canine relationship after postsurgical alignment of mandibular anterior teeth.
orbicularis oris muscle. After the muscle is transsected, the dissection is directed obliquely posteriorly and inferiorly through the mentalis muscle until contact is made with the mental symphysis 5 to IO mm. below the apices of the mandibular incisors. The anterior-inferior tissue flap is retracted inferiorly to expose the anterior mental symphysis. The mentalis muscle and submucosa is incised sharply posteriorly to an area opposite and above the apices of the canine teeth. The mental nerves need not be exposed when the interdental bone incisions are made in the canine-lateral incisor interspaces. Branches of the mental nerve which exit from the mental foramen are identified by subperiosteal tunneling beneath the anterior margins of the incised tissues. Carefully oriented periapical and panographic radiographs aid in locating the foramina. Once the foramen has been located, the mental nerves are identified and carefully isolated by blunt dissection with mosquito hemostats through the margins of the previously made vestibular incision. After the main branches of the nerve are identified and retracted inferiorly, an incision is made through the submucosal tissue above the nerve down to the underlying bone. The incision may be extended posteriorly as far as necessary to accomplish the planned vertical bone incisions. The chin prominence is “degloved” from the mental foramen of one side to the contralateral mental foramen; the lateral part of the body of the mandible posterior to the foramen is exposed similarly if the vertical bone cuts are to be made in the premolar region. The mental symphysis and the lateral aspect of the mandible can now be clearly visualized. When ramus surgery is performed concomitantly, the circumvestibular incision will join with the anterior aspect of the soft-tissue incision which is used to expose the vertical rami. The desired horizontal and vertical osteotomy sites are next etched into the mandible with a No. 701 fissure burr. The inferior ends of the two vertical marks are connected across the midline at least 3 to 5 mm. inferior to the nearest root apices. Animal studies and clinical experience indicate that the nlllnnl circlllatinn iu mnintaind Gth cllh+ra!
Volume 74 Number 3
F@ 2. Case report. Facial appearance treatment.
Subapical
of 38-year-old
osteotomy
279
woman before (top row) and after (bottom row)
bone incisions made within 2 mm. of the apices of the teeth.’ When feasible, however, 3 to 5 mm. provides a safer margin. The index finger is positioned on the lingual mucosa to protect the tissue and feel the burr or saw blade as it transsects the lingual cortex. A periosteal elevator may also be placed to preserve the lingual mucoperiosteum of the lingual cortical plate as the planned osteotomies are accomplished with No. 701 fissure burrs and fine tapered osteotomes. The vertical bone incisions are connected by horizontal ostectomy, performed principally with an oscillating saw blade. Again, the surgeon’s index finger is positioned on the lingual mucosa to feel the oscillating saw blade as it transsects the lingual cortical plate. A fine instrument is placed in the vertical and horizontal bone incisions to determine when the bone has been completely sectioned. The interseptal bone is fractured by malleting fine tapered osteotomes into the interdental osteotomy sites.2 When this is discernible, the dentoalveolar fragment is mobilized by light digital pressure. To facilitate the planned movements, the fragment is carefully tipped lingually to
280
Am. J. Orthod. September 1978
Bell
C.T AGE 38-1
CT AGE 38-g
C. T. -AGE ----AGE
38-l 38-11
&
120 mm I I 127 mm /
0C Fig. 3. A, Cephalometric tracing before treatment lationship and lip muscles relaxed. B, Cephalometric (age 38 years 9 months). C, Composite cephalometric after (broken line, 38 years 11 months) treatment.
(age 38 years 1 month). Mandible in centric retracing after 6 months of orthodontic treatment tracings before (solid line, 38 years 1 month) and
expose the inferior aspect of the mobilized segment. With a periosteal elevator positioned on the superior and lingual aspect of the mental symphysis segment, additional bone sculpturing is done with a fissure burr to facilitate the desired anterior and vertical movements. Similar manipulations are carried out in the vertical osteotomy sites. Bilateral lingual gingival margin incisions are made from one tooth anterior to the planned vertical osteotomy sites posteriorly to the second molar regions. The design of the lingual soft-tissue flap is critical to maximize circulation to the mobilized anterior mandibular dentoalveolar segment by way of the intact lingual mucoperiostum and muscle. 7 :.--..- 1 e-.....-- a,.-- ^-^ Jm,.,,n..nA + Annthr nf the mvlnhvnifi mllqcle origins distal -----a--- -.. -.., V’ “Lr” 1. - -- -_-= _ _ . .0 +h--.- --r---’ - - ---- ---, -Ed
Volume 74 Number 3
Subapical
osteotomy
281
Fig. 4. Centric relation before treatment (age 38 years 1 month).
to the anterior mandibular segment to be moved in order to facilitate anterior repositioning of the segment. Posterior relaxing incisions, which occasionally may be indicated for large anterior movements, are usually unnecessary. Extreme care is exercised to preserve and maximize the attachment of the lingual mucosa to the mobilized segment. The previously prepared interocclusal wafer splint is used to key the segment into the desired position and sculpture the margins of the osteotomized segments appropriately. Finally, the mobilized segment is fixed into the desired position with wire ligatures between the arch wire and the interocclusal wafer splint. Bone grafting of small osseous gaps created by surgery is usually unnecessary. Autogenous particulate marrow grafts are used when clinical judgment indicates the need for grafting. Case report A 3%year-old woman was initially seenfor treatment of an open-bite deformity. The following problem list was evolved after examination of the clinical records: A. Esthetics (Fig. 2, A, B, and C) 1. Frontal: Lip incompetence; excessive exposure of teeth and gingiva
in repose and
function (greater exposure on right than on left side); constricted alar width; and prominent malar bones; 5 to 7 mm. of incisor exposure with lips in repose. 2. Pr@‘e: Slightly obtuse nasolabial angle: relative mandibular retrusion; deep labiomental fold. B. Cephalometric evaluation (Fig. 3) 1 Moderately high mandibular plane angle-SN 2. Lip incompetency of IO mm.
to mandible, 44 degrees.
Am. J. Orthod. Seprember 1978
Fig. 5. Occlusion
after
6 months
of orthodontic
treatment
and before
surgery
(age 36 years
9 months).
3. Retmclined maxillary central incisors. 4. Retropositioned mandibular incisors. C. 1. Dental archform: Maxillary arch asymmetrical in the anteroposterior, vertical, and transverse dimensions; broad and flat palatal vault. Mandibular arch form square in shape. 2. Dental alignment: Moderate crowding of maxillary and mandibular incisors. 3. Dental occlusion: End-to-end molar occlusion; the maxillary anterior teeth were shifted toward the right side; canting of the anterior maxillary occlusal plane (right incisors were lower and positioned more anteriorly than left incisors); bilateral buccal cross-bite with mandible in centric occlusion; bilateral open-bite starting in molar region bilaterally; 5 mm. of incisor overjet (Fig. 4). The treatment plan called for the following: A. Presurgical orthodontic treatment. * Alignment of maxillary arch by proclination of maxillary incisors without extraction and maintenance of space between maxillary canines and lateral incisors for planned interdental osteotomies; uprighting of lingually tipped lower left first premolar tooth (Figs. 5 and 6). B. Le Fort I osteotomy in three segments (Fig. 8) to (1) reduce exposure of teeth and gingiva (3 mm. in left incisor area; 5 mm. in right incisor area; and 7 mm. bilaterally in posterior areas); (2) level maxillary occlusal plane; (3) decrease intercanine width 2 mm. and intermolar width 4 mm.; (4) close anterior open-bite; (5) allow autorotational movement of retropositioned mandible to achieve desired overjet; and (6) correct lip incompetency. C. Mandibular subapical osteotomy to reposition mandibular incisor teeth anteriorly 3 mm. without extraction of teeth (Fig. 1). *Orthodontic
treatment
by Dr. Richard
Buck,
Austin,
Texas.
Volume 74 Number 3
Subapical
Fig. 6. Occlusion 4 weeks after surgical intervention,
osteotomy
at time of release from intermaxillary
Fig. 7. Occlusion after treatment (age 39 years 6 months)
203
fixation.
204
Am. .I. Orthod. September 1978
Bell
Fig.
8. Diagrammatic plan of maxillary and mandibular surgery: Three-piece Le Fort I osteotomy to reposition the maxilla superiorly, narrow the maxilla, and level the maxillary occlusal plane; move four mandibular incisors anteriorly and inferiorly by anterior mandibular subapical osteotomy to increase mandibular arch length; deep labiomental fold made more prominent with local bone graft from body of mandible.
D. Decrease in prominence of labiomentalfold with local bone graft from body of mandible. This would be followed by postsurgical orthodontic treatment to obtain final interdigitation and positioning of teeth (Fig. 8).
Treatment
and follow-up
The maxillary arch was aligned and rotations were corrected with edgewise orthodontic appliances within 6 months. No effort was made to close the open-bite, level the maxillary occlusal plane, or coordinate the maxillary and mandibular arches. These objectives were accomplished by maxillary surgery. All orthodontic treatment in the mandibular arch was done after the planned maxillary and mandibular osteotomies were completed. Postoperative healing after maxillary and mandibular surgical procedures was uncomplicated and associated with minimal morbidity. Intermaxillary fixation was maintained for approximately 4 weeks. Within 5 weeks after surgery, the repositioned maxillary and mandibular dento-osseous segments were clinically firm. Postsurgical orthodontic treatment was completed uneventfully in another 6 months (Fig. 7). With total maxillary osteotomy, mandibular alveolar surgery, and orthodontic treatment, the treatment objectives were achieved after I8 months’ treatment. Superior movement of the maxilla improved facial esthetics by decreasing anterior facial height, differentially decreasing the amount -c v-:-L.... .,*A c.m+L ,,>...n,.,,,.fi ,,,.h;n,r;n” Iin WWVV+=WVJ anal allowing thr retropositioned mandible ...r _, , _... v -P --I I -- -/ -.-.-.-
Volume 14 Number 3
Subapical
osteotomy
285
to automtate forward and upward (Figs. 2, F and 3, C). Increased upper lip prominence, a slightly more acute nasolabial angle, improved lip posture, a small increase in the interalar width, and increased prominence of the paranasal areas combined to achieve an esthetic nose-lip-tooth-chin balance (Fig. 2, D, E, and F). Becauseof retmpositioned mandibular anterior teeth which had relatively little alveolar bone support and a very prominent labiomental fold, mandibular extractions were contraindicated. Orthodontic procliuation of the mandibular incisors would move the teeth out of their supporting bone. Mandibular subapicalosteotomy allowed bodily movement of the four incisor teeth without jeopardizing their bony support and improved the position of these teeth over their supporting bone. Treatment planning without extraction in the mandibular arch obviated the need for surgical advancement of the mandible. Discussion The surgical-orthodontic approach to correction of crowding in adults is particularly useful in cases where the problem area is confined to the anterior part of the maxillary or mandibular arch. Anterior crowding is frequently manifest in the maxillary arch, where anteroposterior deficiency is associated with cleft lip and/or palate or with congenital absence of canines and premolars. In these patients, where there is already insufficient support for the facial soft tissues adjacent to the deficient arch, extraction of premolar teeth will only compromise facial esthetics even more. Surgical techniques similar to those described in this article can be used anywhere in the maxillary or mandibular arches to increase the arch length and facilitate correction of crowded or malaligned teeth or eruption of impacted teeth.5 Posterior maxillary or mandibular segments can be moved posteriorly to increase arch length and facilitate correction of malaligned or crowded anterior teeth in clinical situations in which extractions are contraindicated. The author is indebted to Mr. Mark Bennett for photographs and to Mr. William 0. Winn for illustrations of the surgical techniques. REFERENCES
I. Bell, W. H.: Correctionof 2. 3. 4. 5.
maxillary excess by anterior maxillary osteotomy, ORAL SURG. 43: 323-332, 1977. Bell, W. H., and McBride, Kevin: Immediate surgical repositioning of anterior and posterior maxillary dento-osseous segments, J. Oral Surg. 34: 943-947, 1976. Bell, W. H., and McBride, Kevin: Correction of the long face syndrome by Le Fort I osteotomy, ORAL SURG. 44: 493-520, 1977. Bell, W. H.: Le Fort 1 osteotomy for correction of maxillary deformities, J. Oral Surg. 33: 412-426, 1975. Kale, H.: Surgical operations on the alveolar ridge to correct occlusal abnormalities, ORAL SURG. 12: 515. 1959.
5323 Hurry
Hinvs
Blvd.
(75235)
Texas
0
rthodontic treatment of dentofacial deformities is frequently complicated by crowded and malaligned teeth which are tipped forward off their bony base. The purpose of treatment is to align and move the teeth into the best possible position over their skeletal base. To accomplish this by orthodontic measures alone, it is usually necessary to extract maxillary and mandibular premolars. With such treatment, however, occlusal harmony is frequently achieved at the expense of facial esthetics because the upper anterior teeth and lip are retracted. In addition, the treatment time may be increased. Planning Anterior mandibular subapical osteotomy offers an alternative method of managing selected malocclusions which are associated with minimal to moderate crowding. Persons with a Class II deep bite, dentoalveolar retrusion, normal chin prominence, and deep labiomental fold are potentially good candidates for such treatment. The mandibular anterior teeth are surgically repositioned anteriorly to increase arch length, facilitate postsurgical orthodontic treatment of crowded and malaligned teeth, and obviate the need for extractions. Additional soft-tissue facial support is gained from the advanced dento-osseous segment. The anterior mandibular alveolar segment is moved fotward the distance which, calculated from a Bolton analysis and diagnostic orthodontic setup, is necessary to align the teeth. Careful preoperative occlusal analysis and planning by the surgeon and the orthodontist are essential to select the appropriate interdental osteotomy site and determine the feasibility of the surgical plan. To date, vertical interdental osteotomies have been made only in the canine-lateral incisor or canine-first premolar interspaces. Mandibular
subapical
osteotomy-surgery
technique
For this procedure, the patient is usually placed under general nasoendotracheal anesthesia. When, however, only the incisor teeth are to be repositioned, the surgery is easily carried out with only local anesthesia. A local anesthetic agent with vasoconstrictor is infiltrated into the mental symphysis region for hemostasis. The incision for the anterior mandibular subapical osteotomy is designed to maintain circulation to the lingual and labial aspects of the mobilized dental osseous segment (Fig. 1). Anteriorly, the incision is made through the lower lip mucosa above the labial frenum, midway between the depth of *Associate Professor, The University of Texas Health Science -... ~_. ,.. .a.*..^ uy,6cLJ, CL;;,, F”, Cu~~;,Lfi -. ._..,,.. _. -.-. . .. . .l‘l_\..‘UIILLLI
276
OOG2-9416/78/0374-0276$01.00/O
Center, Department of Surgery, of Dixefxia: Dcfwktieb. 0
1978 The C.V.
Mosby Co.
Volume 74 Number 3
Subapical
osteotomy
277
Fig. 1. Anterior mandibular subapical osteotomy to increase mandibular arch length. A, Typical dental, skeletal, and facial features associated with mandibular deficiency and skeletal-type deep bite; mandible in centric relation and lips relaxed. Note lip incompetence, retroinclined maxillary incisors, retropositioned and crowded mandibular incisors, Class II, Division 2 malocclusion, and deep labiomentai fold. Plan of treatment: Mandibular subapical osteotomy without extraction of teeth to advance lower anterior teeth, increase arch length, and partially level mandibular arch; bilateral sagittal split ramus osteotomies to advance mandible into Class I canine and molar relation; alignment of maxillary arch by orthodontic treatment. Arrows indicate planned directional movements of teeth and dento-osseous segment. B, Mental symphysis degloved to facilitate horizontal and vertical osteotomies. C, Lingual mucoperiosteum undermined distal to mobilized segment to allow segment to be advanced; stippling indicates area of detached mucoperiosteum. D, Maxillary arch aligned by orthodontic treatment; segmental orthodontic appliances used in mandibular arch.
the labial vestibule and the vermilion border of the lower lip. The incision is carried laterally and posteriorly into the most lateral part of the buccal vestibule and terminated at least 1 cm. posterior to the planned vertical osteotomy site. In the premolar region, the initial incision is made through the mucosa only in order to obviate injury to superficial branches of the mental nerves. In the anterior region of the lower lip, the incision is carried sharply through the
278
ml
Am. J. Orrhod. September 1978
Fig. 1. (Cont’d). E, Repositioned mandible in intermaxillary fixation after surgical advancement to Class I occlusion; mandibular anterior teeth are aligned by retraction of anterior teeth into space by subapical osteotomy. F, Class I molar and canine relationship after postsurgical alignment of mandibular anterior teeth.
orbicularis oris muscle. After the muscle is transsected, the dissection is directed obliquely posteriorly and inferiorly through the mentalis muscle until contact is made with the mental symphysis 5 to IO mm. below the apices of the mandibular incisors. The anterior-inferior tissue flap is retracted inferiorly to expose the anterior mental symphysis. The mentalis muscle and submucosa is incised sharply posteriorly to an area opposite and above the apices of the canine teeth. The mental nerves need not be exposed when the interdental bone incisions are made in the canine-lateral incisor interspaces. Branches of the mental nerve which exit from the mental foramen are identified by subperiosteal tunneling beneath the anterior margins of the incised tissues. Carefully oriented periapical and panographic radiographs aid in locating the foramina. Once the foramen has been located, the mental nerves are identified and carefully isolated by blunt dissection with mosquito hemostats through the margins of the previously made vestibular incision. After the main branches of the nerve are identified and retracted inferiorly, an incision is made through the submucosal tissue above the nerve down to the underlying bone. The incision may be extended posteriorly as far as necessary to accomplish the planned vertical bone incisions. The chin prominence is “degloved” from the mental foramen of one side to the contralateral mental foramen; the lateral part of the body of the mandible posterior to the foramen is exposed similarly if the vertical bone cuts are to be made in the premolar region. The mental symphysis and the lateral aspect of the mandible can now be clearly visualized. When ramus surgery is performed concomitantly, the circumvestibular incision will join with the anterior aspect of the soft-tissue incision which is used to expose the vertical rami. The desired horizontal and vertical osteotomy sites are next etched into the mandible with a No. 701 fissure burr. The inferior ends of the two vertical marks are connected across the midline at least 3 to 5 mm. inferior to the nearest root apices. Animal studies and clinical experience indicate that the nlllnnl circlllatinn iu mnintaind Gth cllh+ra!
Volume 74 Number 3
F@ 2. Case report. Facial appearance treatment.
Subapical
of 38-year-old
osteotomy
279
woman before (top row) and after (bottom row)
bone incisions made within 2 mm. of the apices of the teeth.’ When feasible, however, 3 to 5 mm. provides a safer margin. The index finger is positioned on the lingual mucosa to protect the tissue and feel the burr or saw blade as it transsects the lingual cortex. A periosteal elevator may also be placed to preserve the lingual mucoperiosteum of the lingual cortical plate as the planned osteotomies are accomplished with No. 701 fissure burrs and fine tapered osteotomes. The vertical bone incisions are connected by horizontal ostectomy, performed principally with an oscillating saw blade. Again, the surgeon’s index finger is positioned on the lingual mucosa to feel the oscillating saw blade as it transsects the lingual cortical plate. A fine instrument is placed in the vertical and horizontal bone incisions to determine when the bone has been completely sectioned. The interseptal bone is fractured by malleting fine tapered osteotomes into the interdental osteotomy sites.2 When this is discernible, the dentoalveolar fragment is mobilized by light digital pressure. To facilitate the planned movements, the fragment is carefully tipped lingually to
280
Am. J. Orthod. September 1978
Bell
C.T AGE 38-1
CT AGE 38-g
C. T. -AGE ----AGE
38-l 38-11
&
120 mm I I 127 mm /
0C Fig. 3. A, Cephalometric tracing before treatment lationship and lip muscles relaxed. B, Cephalometric (age 38 years 9 months). C, Composite cephalometric after (broken line, 38 years 11 months) treatment.
(age 38 years 1 month). Mandible in centric retracing after 6 months of orthodontic treatment tracings before (solid line, 38 years 1 month) and
expose the inferior aspect of the mobilized segment. With a periosteal elevator positioned on the superior and lingual aspect of the mental symphysis segment, additional bone sculpturing is done with a fissure burr to facilitate the desired anterior and vertical movements. Similar manipulations are carried out in the vertical osteotomy sites. Bilateral lingual gingival margin incisions are made from one tooth anterior to the planned vertical osteotomy sites posteriorly to the second molar regions. The design of the lingual soft-tissue flap is critical to maximize circulation to the mobilized anterior mandibular dentoalveolar segment by way of the intact lingual mucoperiostum and muscle. 7 :.--..- 1 e-.....-- a,.-- ^-^ Jm,.,,n..nA + Annthr nf the mvlnhvnifi mllqcle origins distal -----a--- -.. -.., V’ “Lr” 1. - -- -_-= _ _ . .0 +h--.- --r---’ - - ---- ---, -Ed
Volume 74 Number 3
Subapical
osteotomy
281
Fig. 4. Centric relation before treatment (age 38 years 1 month).
to the anterior mandibular segment to be moved in order to facilitate anterior repositioning of the segment. Posterior relaxing incisions, which occasionally may be indicated for large anterior movements, are usually unnecessary. Extreme care is exercised to preserve and maximize the attachment of the lingual mucosa to the mobilized segment. The previously prepared interocclusal wafer splint is used to key the segment into the desired position and sculpture the margins of the osteotomized segments appropriately. Finally, the mobilized segment is fixed into the desired position with wire ligatures between the arch wire and the interocclusal wafer splint. Bone grafting of small osseous gaps created by surgery is usually unnecessary. Autogenous particulate marrow grafts are used when clinical judgment indicates the need for grafting. Case report A 3%year-old woman was initially seenfor treatment of an open-bite deformity. The following problem list was evolved after examination of the clinical records: A. Esthetics (Fig. 2, A, B, and C) 1. Frontal: Lip incompetence; excessive exposure of teeth and gingiva
in repose and
function (greater exposure on right than on left side); constricted alar width; and prominent malar bones; 5 to 7 mm. of incisor exposure with lips in repose. 2. Pr@‘e: Slightly obtuse nasolabial angle: relative mandibular retrusion; deep labiomental fold. B. Cephalometric evaluation (Fig. 3) 1 Moderately high mandibular plane angle-SN 2. Lip incompetency of IO mm.
to mandible, 44 degrees.
Am. J. Orthod. Seprember 1978
Fig. 5. Occlusion
after
6 months
of orthodontic
treatment
and before
surgery
(age 36 years
9 months).
3. Retmclined maxillary central incisors. 4. Retropositioned mandibular incisors. C. 1. Dental archform: Maxillary arch asymmetrical in the anteroposterior, vertical, and transverse dimensions; broad and flat palatal vault. Mandibular arch form square in shape. 2. Dental alignment: Moderate crowding of maxillary and mandibular incisors. 3. Dental occlusion: End-to-end molar occlusion; the maxillary anterior teeth were shifted toward the right side; canting of the anterior maxillary occlusal plane (right incisors were lower and positioned more anteriorly than left incisors); bilateral buccal cross-bite with mandible in centric occlusion; bilateral open-bite starting in molar region bilaterally; 5 mm. of incisor overjet (Fig. 4). The treatment plan called for the following: A. Presurgical orthodontic treatment. * Alignment of maxillary arch by proclination of maxillary incisors without extraction and maintenance of space between maxillary canines and lateral incisors for planned interdental osteotomies; uprighting of lingually tipped lower left first premolar tooth (Figs. 5 and 6). B. Le Fort I osteotomy in three segments (Fig. 8) to (1) reduce exposure of teeth and gingiva (3 mm. in left incisor area; 5 mm. in right incisor area; and 7 mm. bilaterally in posterior areas); (2) level maxillary occlusal plane; (3) decrease intercanine width 2 mm. and intermolar width 4 mm.; (4) close anterior open-bite; (5) allow autorotational movement of retropositioned mandible to achieve desired overjet; and (6) correct lip incompetency. C. Mandibular subapical osteotomy to reposition mandibular incisor teeth anteriorly 3 mm. without extraction of teeth (Fig. 1). *Orthodontic
treatment
by Dr. Richard
Buck,
Austin,
Texas.
Volume 74 Number 3
Subapical
Fig. 6. Occlusion 4 weeks after surgical intervention,
osteotomy
at time of release from intermaxillary
Fig. 7. Occlusion after treatment (age 39 years 6 months)
203
fixation.
204
Am. .I. Orthod. September 1978
Bell
Fig.
8. Diagrammatic plan of maxillary and mandibular surgery: Three-piece Le Fort I osteotomy to reposition the maxilla superiorly, narrow the maxilla, and level the maxillary occlusal plane; move four mandibular incisors anteriorly and inferiorly by anterior mandibular subapical osteotomy to increase mandibular arch length; deep labiomental fold made more prominent with local bone graft from body of mandible.
D. Decrease in prominence of labiomentalfold with local bone graft from body of mandible. This would be followed by postsurgical orthodontic treatment to obtain final interdigitation and positioning of teeth (Fig. 8).
Treatment
and follow-up
The maxillary arch was aligned and rotations were corrected with edgewise orthodontic appliances within 6 months. No effort was made to close the open-bite, level the maxillary occlusal plane, or coordinate the maxillary and mandibular arches. These objectives were accomplished by maxillary surgery. All orthodontic treatment in the mandibular arch was done after the planned maxillary and mandibular osteotomies were completed. Postoperative healing after maxillary and mandibular surgical procedures was uncomplicated and associated with minimal morbidity. Intermaxillary fixation was maintained for approximately 4 weeks. Within 5 weeks after surgery, the repositioned maxillary and mandibular dento-osseous segments were clinically firm. Postsurgical orthodontic treatment was completed uneventfully in another 6 months (Fig. 7). With total maxillary osteotomy, mandibular alveolar surgery, and orthodontic treatment, the treatment objectives were achieved after I8 months’ treatment. Superior movement of the maxilla improved facial esthetics by decreasing anterior facial height, differentially decreasing the amount -c v-:-L.... .,*A c.m+L ,,>...n,.,,,.fi ,,,.h;n,r;n” Iin WWVV+=WVJ anal allowing thr retropositioned mandible ...r _, , _... v -P --I I -- -/ -.-.-.-
Volume 14 Number 3
Subapical
osteotomy
285
to automtate forward and upward (Figs. 2, F and 3, C). Increased upper lip prominence, a slightly more acute nasolabial angle, improved lip posture, a small increase in the interalar width, and increased prominence of the paranasal areas combined to achieve an esthetic nose-lip-tooth-chin balance (Fig. 2, D, E, and F). Becauseof retmpositioned mandibular anterior teeth which had relatively little alveolar bone support and a very prominent labiomental fold, mandibular extractions were contraindicated. Orthodontic procliuation of the mandibular incisors would move the teeth out of their supporting bone. Mandibular subapicalosteotomy allowed bodily movement of the four incisor teeth without jeopardizing their bony support and improved the position of these teeth over their supporting bone. Treatment planning without extraction in the mandibular arch obviated the need for surgical advancement of the mandible. Discussion The surgical-orthodontic approach to correction of crowding in adults is particularly useful in cases where the problem area is confined to the anterior part of the maxillary or mandibular arch. Anterior crowding is frequently manifest in the maxillary arch, where anteroposterior deficiency is associated with cleft lip and/or palate or with congenital absence of canines and premolars. In these patients, where there is already insufficient support for the facial soft tissues adjacent to the deficient arch, extraction of premolar teeth will only compromise facial esthetics even more. Surgical techniques similar to those described in this article can be used anywhere in the maxillary or mandibular arches to increase the arch length and facilitate correction of crowded or malaligned teeth or eruption of impacted teeth.5 Posterior maxillary or mandibular segments can be moved posteriorly to increase arch length and facilitate correction of malaligned or crowded anterior teeth in clinical situations in which extractions are contraindicated. The author is indebted to Mr. Mark Bennett for photographs and to Mr. William 0. Winn for illustrations of the surgical techniques. REFERENCES
I. Bell, W. H.: Correctionof 2. 3. 4. 5.
maxillary excess by anterior maxillary osteotomy, ORAL SURG. 43: 323-332, 1977. Bell, W. H., and McBride, Kevin: Immediate surgical repositioning of anterior and posterior maxillary dento-osseous segments, J. Oral Surg. 34: 943-947, 1976. Bell, W. H., and McBride, Kevin: Correction of the long face syndrome by Le Fort I osteotomy, ORAL SURG. 44: 493-520, 1977. Bell, W. H.: Le Fort 1 osteotomy for correction of maxillary deformities, J. Oral Surg. 33: 412-426, 1975. Kale, H.: Surgical operations on the alveolar ridge to correct occlusal abnormalities, ORAL SURG. 12: 515. 1959.
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