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Biologic basis for maxillary osteotomies.

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Biologic Basis for Maxillary Osteotomies
Division of Oral Surgery, University of Texas Southwestern
Medical School, Dallas, Texas 75235
Adult Rhesus monkeys were used as experimental models to investigate revascularization and bone healing in different single-stage anterior,
posterior and total maxillary osteotomy techniques.
Microangiographic and histologic studies demonstrated that intraosseous and
intrapulpal circulation to the mobilized maxillary segments were maintained by
the experimental flap designs which maintained intact soft tissue; the fragments healed by osseous union within six weeks without immobilization of the
The treatment of many severe dental-facial deformities is difficult and challenging. Functional and stable occlusions with facial balance and harmony have
been attained in many adult patients by maxillary osteotomy techniques.
The Rhesus monkey serves as an excellent experimental model to develop new
biologically sound maxillary surgical orthodontic techniques.
A large proportion of the adult population with dental-facial deformities due to
severe malocclusion may never receive the
benefits of orthodontic treatment. Many
adults object to wearing orthodontic appliances for the prolonged period of time
necessary to properly treat their malocclusion. Professional careers preclude
many patients from wearing fixed appliances. The condition of the periodontium
and missing posterior teeth which would
usually serve a s anchorage teeth, may contraindicate treatment by orthodontics
The goal of surgical-orthodontic treatment of dental-facial deformities is to provide a functional occlusion with facial balance and harmony. Multiple operations
may be necessary to attain these objectives
as the clinical manifestations of such deformities often defy correction by a single
surgical procedure. Unit recent years,
surgical correction was focused on the
mandible and frequently failed. However,
with the introduction of anterior (CohnStock, '21; Wassmund, '35) and posterior
maxillary osteotomies (Schuchardt, '61 )
and total maxillotomy (Axhausen, '34;
Wassmund, '35), techniques which were
pioneered by European surgeons, restoration of occlusal balance and facial harAM. J. PHYS.ANTHROP., 38: 279-290.
mony was attainable in practically all
When maxillary surgical procedures
were introduced to the United States (Kole,
'59; Murphey and Walker, '63; Mohnac,
'65; Obwegeser, '66), the rationale for
using the various surgical techniques for
correcting dental-facial deformities was
empirical. Basic questions concerned with
the healing of the surgical wounds produced by maxillary osteotomies had not
been investigated. Many surgeons felt that
the maxilla healed by fibrous union. Devitalization of teeth and bone in the mobilized segments had been reported. Varying
degrees of relapse subsequent to posterior
maxillary osteotomy (Schuchardt, '61 ) and
total maxillary osteotomy were reported.
The blood vessels necessary to maintain
circulation to the mobilized bony segments
and teeth had not been studied. Consequently both one-stage and two stage
procedures were devised to prevent impairment of the vascular supply to the mobilized dental-alveolar segments (Schuchardt,
In 1965, a n animal investigation was
designed to delineate the biology of maxillary osteotomy wound healing. Since then
adult Rhesus monkeys have been used a s
experimental models to investigate the re279
Fig. 1 * Perfusion technique (modified after Rhinelander a n d Baragry). AV, air vent; CC,
cannulated common carotid artery; FA, cannulated femoral artery; Hg, mercury; HP, house
air pressure; M, “U” tube manometer; and P, perfusant.
vascularization and bone healing associated with various maxillary techniques
(Bell, ’69; Bell and Levy, ’70, ’71). The
Rhesus monkey, Macaca mulatta, was
selected as the experimental animal because of anatomic, physiologic, and dental
similarities to the human.
Since maxillary osteotomies are usually
performed in adults, large, male Rhesus
monkeys, 8 to 14 years of age, weighing
a n average of 9 kg, were chosen for study.
Acrylic splints were made from stone study
models of each monkey’s dentition. Various
one-stage anterior maxillary, posterior
maxillary (fig. 3 ) and total maxillary
osteotomies were performed by various flap
designs. The mobilized maxillary segments
were fixed with acrylic splints ligated to
the anterior and posterior teeth with interdental wires. Because the mandible was
not immobilized, the animals were fed a
normal diet.’ Unoperated monkeys served
as controls.
The animals were killed 1, 3, 6 and 24
weeks after surgery. Before death each
animal was premedicated and anesthetized.
The right and left common carotid
arteries were exposed, cannulated, heparinized and perfused with barium sulfate *
under a constant pressure of 120 mm Hg
(Rhinelander and Baragry, ’62; Bell, ’69)
(fig. 1) . The heads were disarticulated and
fixed in formalin. Microangiographic and
histologic study was carried out after
1 Zu/Preem Science Diet, Theracon Laboratories,
Topeka, Kansas.
2 Micropaque.
Illustrations in figures 1-6 were included in the
article, “Revascularization and bone healing after anterior maxillary osteotomy,” by W. H. Bell and B. L.
Levy, in Journal of Oral Surgery April 1969. Illustrations in figure 7 were included i i the article, “Correction of skeletal type of anterior open bite,” by W. H.
B,ell, in Journal of Oral Surgery, October 1971. Copyright by the American Dental Association. Reprinted
by permission.
Fig. 2 Microangiograms of 1 mm transverse tissue slices from premolar (A) and
molar region ( B ) of control animal: buccal (B), palatal (Pa), maxillary sinus (MS) and
nasal cavity ( N ) blood vessels penetrating bone and anastomosing with intramedullary
blood vessels ( I ) and periodontal vascular plexus (Pe); P, premolar tooth; M, molar tooth;
T, turbinate.
each maxilla was decalcified, dehydrated,
cleared, and embedded in paraffin and
beeswax. Serial 1 mm transverse, sagittal
and horizontal tissue slices were cut from
the specimens for microangiographic
study. Each 1 mm tissue slice was then
cut at 7 for histologic study.
Control animals. The injection medium
was distributed through most of the cancellous intraosseous, intrapulpal and soft
tissue blood vessels (fig. 2). The maxilla
was vascularized by a highly complex
interconnected network of vessels that
terminated in the gingiva and mucosa as
capillary loops of variable length (Bell and
Levy, '71). All dental osseous components
received blood from a multiplicity of
sources. Gingival, buccal, labial, palatal,
nasal, and maxillary sinus vessels penetrated and traversed the cortical bone and
anastomosed with the periodontal plexus
encircling the teeth. Dental pulps were
vascularized by interosseous dental alveolar vessels and branches from the periodontal plexus. Submucosal palatal vessels
anastomosed near the midline of the palate
with vessels from the opposite side. Buccal
and gingival tissues received blood from
buccal soft tissues and from intraalveolar
vessels. Soft tissue and intraosseous vessels
supplied blood to the reticulated vascular
plexus making up the periosteum. Vessels
of the gingiva, periodontal plexus, lingual
mucosa and labial alveolar mucosa were
interconnected by vascular anastomoses.
The nasal cavity was lined with a vascular
net work of variable thickness; the turbinates by a relatively thick vascular plexus
that was surrounded by a thin reticulated
vascular plexus. The avascular nasal
septum was covered by a reticulated vascular plexus.
Experimental animals. The surgical
soft tissue wounds produced by various flap
designs healed by primary intention, without detectable postoperative infection. The
dental alveolar segments were freely movable one week after surgery and slightly
movable after three weeks. After six weeks
there was clinical union of the osteotomized
segments. The individual teeth in the mobilized bone segments remained stable.
There was generalized distribution of
the micropaque throughout the intraosseous and intrapulpal tissues of all mobilized osseous segments (figs. 4, 5). The pulp
Fig. 3 Schematic drawing of soft tissue and
bone incisions used for posterior maxillary osteotomy in experimental animals.
canals of several teeth adjacent to the vertical interdental bone cuts were not vascularized because their apical blood supply
was severed by labial and buccal bone cuts
through the teeth apices. The pulp canals
of all other teeth, however, were viable
and vascularized despite the fact that vertical interdental osteotomies were made
between closely spaced teeth and subapical
bone cuts just above the apices of teeth,
Microangiographic study of the one week
specimens revealed focal areas of intraosseous ischemia in the margins of the sectioned alveolar bone segments that were
separated by a n avascular zone (fig. 4).
Within three weeks the circulation between
all of the sectioned bone fragments had
been reconstituted. The raised buccal and
labial soft tissue flaps were reattached to
the underlying bone as shown by the many
periosteal blood vessels penetrating the
buccal and palatal cribriform plates and
anastomosing with intraosseous blood vessels and the periodontal vascular plexus
(fig. 5 A ) . Histologically, there was a n intense osteoblastic proliferation within the
marrow spaces and around many of the
spicules of the spongiosa (fig. 5B). Minimal osteonecrosis was found throughout
the mobilized maxillary bone segments.
Some empty lacunas were present in the
proximal and distal margins of the bone
Six weeks after the osteotomies there
was no detectable intraosseous or intrapulpal ischemia. The reparative response
in the endosteal vascular bed appeared
more intense than it did in the periosteal
vascular bed. Histologically, the proximal
and distal bony segments were united with
cancellous bone.
Twenty-four weeks after maxillary
osteotomies, the periosteal and endosteal
circulatory beds had been virtually reconstituted to their normal vascular architecture. The endosteal-periosteal anastomosis
through cortical bone had been restored.
Histological examination of the osteotomy
wounds revealed healing of the cortical
bone and remodeling of the spongiosa.
The results of these clinically analogous
animal studies indicated that single-stage
anterior, posterior, and total maxillarv
osteotomies were biologically sound surgical procedures. Preservation of the integrity of the incisive canal or greater palatine arteries was not essential to maintain
circulation to the anterior or posterior
maxillary dental alveolar segments. The
intraosseous and soft tissue collateral circulation and the freely anastomosing
gingival, palatal, floor of the nose, maxillary sinus, and periodontal plexuses, per-
Fig. 4
Microangiogram of 1 mm sagittal tissue slice one week after posterior maxillary
shows generalized intraosseous and intrapulpal distribution of injection medium;
zone (arrows) between margins of vertical bone cut between premolar teeth; MS,
sinus; C, canine tooth; T, tuberosity.
mitted many technical variations of maxillary osteotomies, without jeopardizing the
blood supply to the maxillary dental alveolar segments (fig. 6). Intraosseous and
intrapulpal circulation was not significantly altered by interdental and subapical
alveolar osteotomies when the bone cuts
were made away from the apices of the
teeth; maximal attachment of the mucoperiosteum on the lingual or buccolabial
surface of the mobilized osseous or dentalosseous segments was preserved. When
carefully pedicled flaps were used to maintain these attachments, the segments could
be mobilized and transposed safely in any
The encouraging results attained in the
animal wound healing studies generated
much enthusiasm and confidence in clinical maxillary osteotomies. Adult dentalfacial deformities which previously could
not be treated by either mandibular surgery
or orthodontics without severely compromising the result, could now be treated in
a practical period of time. Treatment of
such a case (skeletal type of anterior open
bite) is shown in figure 7. Multiple maxillary osteotomies, genioplasty and orthodontics effected a stable and functional
occlusion with facial balance in 14 months.
Since 1967, 20 skeletal Class I1 malocclusions have been treated by anterior
maxillary osteotomy, genioplasty and orthodontics (12 patients had no orthodontics;
8 patients had orthodontics). The average
treatment time was approximately nine
Fig. 5A Microangiogram of 1 mm transverse tissue slice from first molar region three
weeks after posterior maxillary osteotomy shows proliferation of endosteal ( E ) and periosteal
( P ) circulatory beds; reattachment of buccal and palatal mucoperiosteal flaps to underlying
bone; vascularization of pulp canal from periodontal vascular plexus and accessory root
canal (arch); Buccal ( B ) ; and palatal osteotomy sites ( P a ) ; nasal cavity ( N C ) ; first
molar tooth ( T ) .
months. Five patients with retromaxillism
associated with mandibular prognathism
were treated by surgically advancing the
entire maxilla (total maxillary osteotomy).
Seventeen patients with bimaxillary dental
protrusion were treated by surgical ortho-
dontic techniques in a n average of 8.5
Long-term clinical and radiographic
studies of the patients who have had maxillary alveolar surgery showed no periodontal
problems and minimal crestal alveolar
Fig. 5B Photomicrograph of buccal bone. Periosteum is thickened by fibrous connective
tissue. Osteophytes are seen beneath periosteum. Osteoid and new bone bridge fragments.
Endosteal osteoid appears limited to proximal fragment ( H & E, original magnification X 8).
Fig. 6 Schematic composite illustration of
showing freely anastornosing gingival plexus,
artery, intraalveolar vessels, apical vessels, and
mits anterior maxillary osteotomies without
maxillary segment and teeth.
blood supply to anterior maxillary region
palatal plexus, periodontal plexus, labial
pulp vessels. This vascular architecture percompromising circulation to the anterior
Fig. 7A
Facial profile before treatment
Fig. 7B
Facial profile after treatment.
Fig. 7 Case Report. Skeletal type of anterior open bite with Class I1 malocclusion treated in 14
months by surgical-orthodontic techniques. Maxillary canine teeth were extracted to facilitate posterior maxillary osteotomies and retraction of procumbent maxillary incisors. Lower first premolar
teeth were extracted to allow orthodontic correction of crowded mandibular dental arch.
Fig. 7C
Occlusion before treatment.
Fig. 7D
Occlusion after 14 months of surgical-orthodontic treatment.
of treated cases demonstrated remarkable
stability of dental-skeletal changes effected
by maxillary osteotomies. They also
showed minimal resorption of the transposed mental symphysis bone segments.
The author wishes to thank Miss
Rebecca Sprowls, Miss Judy Peterson, and
Mrs. Dorothy Gilbert for technical assistance in preparing this paper.
Fig. 7E Posterior maxillary osteotomy to level
maxillary occlusal plane; vertical facial dimension is reduced and chin contour restored by
anterior sliding genioplasty.
bone loss in the interdental osteotomy
sites (between 1 and 2 m m ) . (Bell and
Dann, in press). All teeth in the alveolar
segments, except one (subsequently retained by endodontic therapy), tested vital
within eight months after surgery. There
was no radiographic evidence of root resorption. Long-term cephalometric studies
Axhausen, G. 1934 Zur Behandlung veralteter
disloziert gehhilter Oberkieferbrueche. Dtsch.
Zahn Kieferheilkd, I : 334.
Bell, W. H . 1969 Revascularization and bone
healing after anterior maxillary osteotomy:
a studying using adult rhesus monkeys. J. Oral
Surg., 27: 249-255.
1971 Correction of skeletal type of anterior open bite. J. Oral Surg., 29: 706-714.
Bell, W. H., and B. M. Levy 1970 Healing after
anterior maxillary osteotomy. J. Oral Surg.,
28: 728-734.
1971 Revascularization and bone healing after posterior maxillary osteotomy. J. Oral
Surg., 29: 313-320.
Fig. 7F Schematic diagram showing buccolabial mucoperiosteal flap design for anterior
maxillary osteotomy; horizontal subapical osteotomy is directed palatally to and through palatal
cortical plate; digital pressure on palatal mucosa
indicates when lingual cortices are sectioned; vertical interdental bone cuts are facilitated by
envelope type of flaps of labial epithelium
( incision ).
Bell, W. H., and J. Dann 1973 Correction of
Class I1 Malocclusion by anterior maxillary
ostectomy and genioplasty. Amer. J. Orthodont.,
in press.
Cohn-Stock, G. 1921 Die chirurgische Immediatregulierung der Kiefer, speziell die chirurgische Behandlung der Prognathie. Vjschr.
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Fig. 7G Cephalometric tracings before (solid
line) and after (broken line) treatment, showing
reduction of anterior facial height, restoration of
chin contour, closure of open bite, improved lip
posture and lip seal, and leveled maxillary
occlusal plane.
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Obwegeser, H. 1966 American Society of Oral
Surgery comprehensive conference on oral
surgery, Walter Reed Army Medical Center,
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