406 B. L. GAINSFORTH AND L. B.

HIGLEY

ginning of mass distal movement in the maxillary denture. This would un-
doubtedly provide greater stability and resistance to displacement of the teeth
in the mandibular denture. It also suggests the advisability, in the second
type of case, of using Class III elastics on a headgear at night to prevent the
mandibular teeth from being displaced forward.

REFERENCES

1. Tweed, Charles N.: Indications for the Extraction of Teeth in Orthodontic Procedures,
AK J. ORTHODONTICS AND ORAL SURG. 30: 405, 1944.
2. Stein, Samuel H.: Rationale of Treatment With the Modified Edgewise Arch Mechanism,
AM. J. ORTHODONTICS AND ORAL SURG. 27: 648, 1941.
3. Stein, Samuel H.: Treatment With the Modified Edgewise Mechanism, J. Am. Dent. A.
30: 375, 1943.
Sved, Alexander : Principles and Technique of Modified Edgewise Arch Mechanism, AM.
J, ORTHODONTICS AND ORAL SURG. 24: 635, 1938.
4. Stein, Samuel H.: Treatment With the Modified Edgewise Mechanism, J. Am. Dent. A.
30: 375, 1943.
509 MADISON AVENUE

A STUDY OF ORTHODONTIC ANCHORAGE POSSIBILITIES IN

BASAL BONE”

B. L. GAINSFORTH, D.D.S., M.S., AND L. B. HIGLEY, B.A., D.D.S., M.S.t

PURPOSE

T HE problem of anchorage has been one of the most difficult in the field of
orthodontics. In the past, teeth have been used as a means of obtaining
anchorage for the movement of other teeth and for the correcting of deformity
in the facial bones. It has been found, however, that the teeth selected for
the anchorage often move simultaneously with those in which movement is
desired and that little or no effect can be produced on the basal bone because
of the instability of teeth when used for the purpose of anchorage. Since
teeth have been found to lack sufficient stability to produce certain changes
desired in the dentures and basal bone, some other source of resistance has
become desirable. Therefore, it was thought that if anchorage could be gained
from a point within the basal bone, stability would be greatly increased. It
was the purpose of this investigation, therefore, to test a method of basal bone
anchorage.
DISCUSSION

Throughout the history of orthodontics there have been repeated efforts to

improve the method of resisting the forces applied through the mechanisms used
to bring about tooth movement. In the text of Angle1 we find the following well-
worded statements : “According to the well-known law of physics, action and
reaction are equal a.nd opposite, hence it must follow that the resistance of
anchorage must be greater than that offered by the tooth to be moved, other-
wise there will be displacement of the anchorage and failure in the movement
of the teeth to the extent, or, possibly, in the direction desired. The sources
*Thesis submitted in partial fulfillment of the requirements of the University of Iowa
for the degree of Master of Science.
tProfessor of Orthodontics, University of Iowa, College of Dentistry.
 ORTHODONTIC ANCHORAGE POSSIBILITIES IN BASAL BONE 407

at our disposal for securing anchorage or resistance are, first, the teeth th&n-
selves, and second, sources external to the teeth. . . .”
In the usual orthodontic appliance one tooth is pitted against, another
t,ooth, or one or more teeth are pitted against two or more teet,h which, by
reason of t,heir position, size, number, or number of roots, offer the resistance
necessary to bring about the movement of the weaker members of the group.
Since Stuteville2 has shown that a force of as litt,le as 5 grams will cause t,ooth
movement. and Schwartz3 has shown that from 20 to 26 grams of force is the
optimum amount to be used in the movement of teeth, then it is logical that,
any intermaxillary or intramaxillary anchorage, using teeth, is reciprocal.
Brodie, Bercea, Gromme, and Neff4 support the above with this statement:
“F’irst of all it should be recognized that there is no such thing as t,rue anchor-
age available within the mouth. We have at, our command only different
degrees of resistance. These differences arc determined mainly by (1) the
form and area of the root surfaces and (2) the nature of t,he surrounding bone.”
Sved5 states that the forward tendency of human teeth is a natural char-
acteristic. Atkinson6 says, “In the human jaw the tendency of the teeth is to
drift forward.” Tweed,? in discussing his treatment of Class II, Angle places
so much importance on the avoidance of forward movement of lower teeth,
while attempting to move upper teeth back that he practices a very elaborate
mechanical system of “anchorage prepara,tion” in the lower arch.
MargoW finds, from a cephalometric analysis, that the best orthodontic
results in white children are those in which the mandibular incisors are vertical
and form a right angle with the mandibular plane. A follower of that theory
would agree that some means of anchorage is needed to prevent the forward
movement of lower teeth, especially tippinh rr of the anteriors which occurs in
so many cases during treatment.
One of us,’ in a recent publication, has shown by a series of cephalometric
roentge&ograms that a deformity, as in Class II, does not necessarily follow
a set pattern, that the teeth may be forward or back from their proper position
on the bony base and that many times there is actually a distal locking of the
mandible itself. Also, since there is ample possibility of loss of anchorage,
there is, therefore, a need for some means of transferring anchorage and stimu-
lation to the basal bone rather than merely to teeth. In the publication just
mentioned9 it is stated: “Perhaps too long we have attempted to stimulate
basal bone growth through the media of the teeth but obtained, for the most
part, only alveolar bone change. . . . At present, if it is possible to change basal
bone, it is accomplished through st,imulation derived by the application of
force to the teeth. In the future, when present methods fail, stimulation may
be attempted by direct application of force to the basal bone.”
Therefore, the factors which provoked the work described in this report
were twofold : first, to find a means of anchorage other than teeth ; second, to
transfer stimulation to basal bone for the motivation of mandibular growth.
Occipital anchorage is one answer to this first factor. It has been observed
that while occipital anchorage may be effective, it depends entirely upon the
cooperation of the patient for its success. Then, too, it seems to cause more
distress in children of a nervous temperament and, when used with a chin
strap in Class III, Angle, it interferes with breat,hing when the child has a
cold or hay fever in certain seasons. Also, because of its unsightly appearance
and inconvenience, it can be utilized mostly at night only. Both of these dis-
408 B. L. GAISSFORTH AND L. B. HIGLEY

advantages could be eliminated if bone anchorage within the mandible were

possible.
In the Manual of B’ractures, by Shaar and Kreuz,lO some of the history of
metal appliances in bone surgery is given. We find that Clayton Parkhill in-
serted screws from cortex to cortex in bone surgery in 1897, Codivilla used pins
in leg-lengthening operations in 1904, and Stader introduced his splint in
December, 1941, after which it was used in 157 orthopedic cases by Shaar and
Kreuz prior to their publication of 1943. considerable importance seems to be
placed on the necessity of keeping the tissue dry around the pin. Pin seepage
is spoken of in nearly all publications on the subject of external skeletal fixation
and there is some controversy as to whether this seepage is always infectious or
whether it may in certain cases be free from infection.
The thought then occurred that if some means of pin or screw attachment,
might be made to the ramus of the mandible, intraorally, as a means of elastic
attachment, it could be used not only in moving teeth but in exerting a pull on
the mandible in cases of distal positioning of that member. The pins of the
Stader splint were applied through the skin aseptically, and the point of in-
sertion kept dry and free from infection from outside. Any screw or pin in
the mouth to be used as an orthodontic attachment would have to project
through the mucosa and would form a communication for the oral fluids from
the mouth to the bone itself. The only hope for success then would be in some
natural immunity of the oral tissues, not possessed by most other body tissues.
It is reasonable to believe that this immunity might exist in some degree. One
has but to reflect on the condition which exists at the site of the average dental
extraction : bone exposed, saliva in the wound carrying with it millions of
microorganisms of various types and virulence, food and debris collecting
there later, and possibly trauma to the bone at the time of extraction. Trans-
fer this same condition to the tibia and an amputation or worse would prob-
ably result.
Bernier and Canbyll speak of the immunity of the oral tissues when they
say, “It appears that in minor surgical operations within the oral cavity,
whether or not they involve the implantation of vitallium, there is considerably
lessened possibility of secondary inflammatory reaction. This, of course, is
borne out in the daily practice of the average dental surgeon. ”
In the early oral surgery by Brophy,12 some of it before the turn of the
century, silver wires were passed through the maxilla from side to side for
closure of cleft palate, These wires were passed in pairs through lead plates
in the mucobuccal fold on each side of the face and the ends twisted to hold
the bony members toward the midline for the fusion of flaps. This was a
type of basal bone anchorage in which the metal appliance communicated
from bone to oral cavity. Little mention is made of infection except to give
local treatment to be used in the event that infection occurred.
Venable and Stuck13 are only two of many workers who advocate the use
of vitallium where implantation of a metal is needed. Their report contains
the following statements : “. . . hundreds of operations have been performed
by many surgeons in which vitallium appliances have been used. After six
years’ experience in hundreds of cases, it is now well established that vitallium
is the most inert alloy currently used in surgery. As this record has become
known, vitallium appliances of diverse types have been designed by surgeons
in other fields than orthopedic surgery. It is this development which we wish
to report to demonstrate the protean utility of this alloy and its complete
 OR’l’1JO1~OS’~IC .\NCl IORA~:IC I’OSSIBII,ITIES IN BAS.ZI, BONE 409

tolerance to the various fluids and secretions of the body because of its chemi-
cal and electrolytic inertness.
In the application of vitallium to the bones of the jaws, mandible and
maxilla, Bernier and Canby’l have implanted screws of this metal in the man-
dibles and one maxilla of monkeys. Some were placed extraorally, projecting
through the skin, and some were placed intraorally in the alveoli of the
canines. The screws remained in place except when forcibly removed by the
animal. They were left in place three months, aft,er which microscopic exami-
nations were made of the screw sites. These authors said that vitallium was
extremely well tolerated by the tissues but the incidence of secondary infection
could not be discounted. These screws, however, became covered wifh a mem-
brane when placed intraorally and therefore could not be used as a means of
orthodontic anchorage. Nevertheless this statement by Bernier and Canby”
was of interest: “When it [vitallium] is inserted intraorally this possibility
[of infection] is considerably lessened. . . . It appears that vitallium alloy
remains essentially inert when in contact with the body tissue. This has been
adequately explained on the basis of the total absence of any electrolytic force.”
Therefore, since the literature points to a need for basal bone anchorage
and since there is evidence that the tissues of the mouth may be more tolerant
of foreign objects than other body tissues, it was decided to conduct an experi-
ment on six dogs and attempt to gain a point of anchorage in the ramus of the
mandible by means of a vitallium screw hook placed in the bone.

Fig. l.-The Coe-Loid impressions were poured in artificial stone with Snow-White art POP
tions and articulated for study of the occlusion and for design of appliance.

EXPERIMENTAI, PROCEDURE

Six dogs, mongrels selected from the stock of the University of Iowa
Medical Laboratories, “were used in the animal experimentation which was
done in connection with this st,udy. The animals varied in weight from 221/
to 29 pounds and were fed on a diet of Purina Dog Chow. No operating was
done until the animals had been on this diet for fourteen days. All operations
were done under general anesthetic: nembutal, 15 per cent, in a solution of
ethyl alcohol, administered intravenously in the hind leg of the dog. Com-
plete relaxation was obtained immediately and lasted for at least three hours.
Each dog in turn was anesthetized and impressions were taken in Coe-
Loid, using trays constructed especially for the dog dent,ition. Casts were
poured in stone and the appliances were constructed upon these casts (Fig. 1).
The appliance in each case was placed during the second anesthetization as
were the screw hook and elastic band for traction.
410 B. L. GAINSFORTH AND I,. B. HIGLEY

The problem in this study was to test some means of basal bone anchorage.
It was desired to attach an appliance to the upper canine because of its’
anatomy and ease of banding. The logical place to attach to the basal bone
was in the ramus of the mandible. The only point which seemed practical to
be used as a site for screw insertion was immediately distal to the last man-
dibular molar. Unfortunately, even this point in the dog skull is closely
crowded behind the tuberosity of the maxilla when the teeth are closed and
especially so in the living dog with the soft tissue on the bony framework.
Mote, too, that a straight line from that point of insertion to the upper canine
of the same side would pass across the biting surface of the upper and lower
second molars and lingually to the first molars and third premolars (Fig. 2).
This made it necessary to pass the line of force outward around the great
curve of the line of teeth.

Fig. 2.-Occlusal view of a disarticulated Collie skull. Black line shows the straight
line of force from the point of screw insertion in the mandible to the canine. Note that this
line would pass through the molar biting surfaces. For this reason a cast overlay was used
on the flrst maxillary molar in the appliance designed.

For Dogs 1, 2, 3, 4, and 5, each appliance was constructed as follows:

(Example.. Fig. 3) A silver overlay, the thickness of two layers of 30 gauge
wax, was cast to fit the upper first molar. This overlay was constructed with
a buccal flange in line with the axis’of the tooth. This flange was perforated,
after casting, to form a hole approximately 0.050 inch in diameter, and to act
as a buccal guide for an arch wire. A pinch band was constructed, of 0.003
inch stainless steel to fit the canine tooth, and a stainless steel wire 0.040 inch
in diameter was spot-welded to the outer surface of this band. The 0.040 inch
wire was bent gingivally and made to follow at the level of the gum line to
the first molar, then occlusally and back through the perforation in the buccal
flange on the molar overlay (Fig. 3).
A vitallium screw of the type used in the Berry jaw-fracture applianceld
was cut down to an over-all length of about 13 mm. The head of the Berry
screw contains a transverse perforation through which a piece of 0.040 inch
stainless steel wire can be passed. This was done, and the wire was bent .to
 ORTHODONTIC ANCHORAGE POSSIBILITIES IN BASAL BONE 411

form a hook to project from the soft tissue when placed in the mandible of
the dog and to receive one end of the elastic to be used in supplying the trac-
tion, the other end of the elastic to be attached to the hook at the distal end
of the upper arch wire.

Fig. 3.--.Skull of Dog 3 with appliance constructed as used on opposite side in life.
Force is applied through the traction of the XX elastic which connects the two hooks. The
arch wire is welded to the canine band and slides freely in the perforated buccal flange of
the molar overlay.

Fig. 4.-Dog 3 with appliance placed on left side (in life). The screw was inserted through
two cortices of bone, from the anterior border of the ramus to the masseteric fossa.

Vitallium was chosen as the metal to be used for the screws to be placed
in the mandibles because of t,he wide use and acceptance of this metal in all
types of bone surgery as already stated. It was theorized that the use of an
elastic to supply the force or traction would eliminate any electrolytic action
which might occur if the appliance on the teeth were of a different potential
from that of the screw.
412 B. L. GAINSFORTH AND L. B. HIGLEY

Dog 6 and Dog 1 (second test) were used to test the reaction to screws
placed in the mouth with no traction applied. ,
Dog 5 (second test) and Dog 2 (second test) were used to test the reaction
to a stainless steel ring placed in the mandibular bone with traction applied.
These additions to the appliance design of the first five tests will be explained
under the report of results.
The Operation.-The operation on each dog was done under a general anes-
thetic after the appliance was completed and ready to be placed. A surgically
clean procedure was used with sterile instruments and an isolated field of
operation, but no antiseptics or solutions were used in the wound, The animal
in each case was placed on the operating table with the head-holder in place,
and an incision was made in the tissue covering the anterior border of the
ramus just distal to the last mandibular molar. The bone at this point in the
dog has a slight groove on the anterior surface and this was used as a starting
point for the placing of the screw. A pioneer hole was drilled in the bone with
a bit 2.4 mm. in diameter, just large enough to allow the screw to be started,
or about the diameter of the screw minus the threads. A hand drill was used
in every case in order that there would be no heat developed in the drilling
process to cause injury to the surrounding bone.
A vitallium screw of the Berry type, as previously described, was placed
in the ramus, following the pioneer hole, using a pair of parallel jawed pliers
with a great deal of force, giving complete rigidity of the attachment. Follow-
ing this, the upper canine and the upper first molar of the same side were
isolated, washed with alcohol, and dried. The silver overlay and pinch-band
appliance were placed with a mixture of oxyphosphate of zinc cement and
held in place until set. An orthodontic elastic was then placed from the hook
of the arch wire to the hook at the end of the screw to supply the traction
force (Fig. 3). It was attempted to choose an elastic in each case which would
give, as nearly as possible, the amount of force in the usual intermaxillary
appliance used on human patients. The forces ranged from 140 grams to
200 grams in the closed relationship of the jaws. Roentgenograms were taken
to show appliance design and tissues involved (Fig. 4).
Tests were made, using two dogs wit,h screws placed as described but
without traction applied. Two more tests were made using a stainless steel
ring which passed around a portion of the bone of the ramus and ended in a
hook to which traction was applied. Further details are given in the report
of results that follows.
RESULTS

Screw With !&action.-Dog 1 showed no visible ill effects following the

placement of the screw and appliance until the third to seventh days when there
was some soreness about the screw. There was very little redness of tissue, but
after the eleventh day following the operation there was some loosening of the
screw, and it came out in sixteen days, and the wound healed. Approximately
200 grams of traction were applied to the screw in this test.
Dog 2 continued to eat well after the appliance was placed. Some sore-
ness developed in the region of the screw from the second to the ninth day,
after which it greatly decreased. In seventeen days the elastic was lost’and
the dog was given an administration of ether for the placement of a new one.
After the eighteenth day there was some loosening of the screw. It was lost
in twenty-one days, and the wound healed. The traction over a period of
 ORTHODONTIC .%NCHORAGE POSSIBILITIES IN BAUL BOKE 413

twenty-one days resulted in a tooth movement of 1 mm. A force of 140 grams

was used.
On Dog 3 an elastic was used which exerted 160 grams of traction on the
screw when the jaw was closed (Fig. 4). The animal ate well and allowed
examination of the appliance without anesthesia. In thirty days there was
some inflammation, but the appliance was still active. In thirty-five days the
screw was out and the wound healing. The dog was sacrificed on the fifty-
third day and the skull was cleaned and bleached for study. An examination
of the bony material thus obtained (Figs. 5 and 6) showed the following:
The site at which the screw was placed in the left ramus remained as a
hole 5 mm. in diameter (Fig. 5), though the screw had been only 3.4 mm. in
diameter outside the threads. A perforation is seen in Fig. 6 extending
through the ramus at the point formerly occupied by the apex of the screw,
opening into the masseteric fossa. There were tiny perforations resulting from
an increase in vascularity over an area around the screw site, 15 mm. in diam-
eter. The unoperatcd ramus on the right side showed no such evidence of vas-
cularity; therefore, it was concluded that this was a reaction to the placement
of the screw. As a result of the orthodontic force there was a movement of
the upper left first molar 1.5 mm. toward the midline. The canine, being a
deep-seated tooth in the dog, offered sufficient resistance to prevent more than
0.2 mm. of distal movement, but the resultant lingual force of the elastic
Fig. 5.

Fig. 6.
Fig. 5.--Left mandible of Dog 3 after the screw had been in place for thirty-one days.
Fig. B.--Lateral view of left mandible of Dog 3. from the buccal. Perforation occurred
at the end of the screw, which was inserted through the bone from the anterior. A slight
amount of bone repair has taken place.
414 B. L. GAINSFORTH AND L. B. HIGLEY

caused the lingual movement of the first molar as given. Thus tooth move-
ment was ohta.ined by anchorage to the basal bone.
Dog 4 was of the Spitz type, weight 20 pounds, and the bone structure
was lighter than is desirable for easy operation. However, the screw was
placed and a traction of 160 grams applied to it by means of an elastic, size
XX, stretched 20 mm. at rest. The dog showed no signs of discomfort while
wearing the appliance, ate well, and was very active at all times. The elastic
was lost in nineteen days, and the screw came out in twenty-six days. After
forty days from placement of the screw, the dog was again anesthetized and
an incision made to examine the bone at the point where the screw had been
placed. The bone showed an indentation at the screw site with a tough car-
tilaginous tissue where the screw had come out. There seemed to. be no
necrotic tissue present, but the last mandibular molar was quite loose and was
easily flipped out of the arch with a periosteotome. This was concluded to
be evidence of rarefaction of the bone in that area, especially after the post-
mortem bone picture of Dog 3 (Fig. 5). Measurement showed a 1 mm. de-
crease in the cuspid to first molar distance.
Dog 5 was a 34-pound animal with a well-developed bone structure. A
screw and appliance were placed with 160 grams of traction. Only a limited
degree of soreness developed, and the animal would allow examination of .the
mouth at any time. In twenty-nine days the screw came out, and the wound
healed. Thirty-six days after the operation the dog was again anesthetized,
and an incision was made to examine the old screw site. The indentation
remained, the hole was filled with a fibrous material, and there was apparently
no necrotic tissue present. There was a small amount of scar tissue in the
mucosa, probably from the original incision.
Screw Without Traction.-Dog 6 was anesthetized and a vitallium screw
was placed in the left ramus as on Dogs 1, 2, 3, 4, and 5. In&his case, however,
there was no appliance on the teeth and no traction was applied to the screw.
The head of the screw projected through the tissue about 3 mm. but did not
interfere with the closure of the jaw in any way. There was very little sore:
ness apparent in the mouth of this dog, and the screw came out and was lost
in twenty-one days. The wound healed readily and there was no apparent
sloughing or drainage.
Dog 1, having lost a screw from the left mandible, was used again two
weeks after that loss for the test of reaction to a screw without traction. This
is referred to as Dog 1 (second test), This time the right mandible was used
and the screw placed as in Dog 6 with no traction applied. The screw was
lost in twenty-one days.
In these last two tests there was apparently less soreness about the screws
than in those animals where traction was applied. This may have been due to
the absence of traction. However, the short time the screws were retained
would suggest that the loss of all of the screws may have been due to a cellular
reaction and that the traction used in the first five of the series may have had
very little effect on the time required for loss of the screws.
Ring With Traction.-Dog 5 (second test) was anesthetized and a hole was
drilled from the anterior border of the ramus straight back into the masseteric
fossa. An annealed 0.040 inch stainless steel wire was passed through the hole,
forward around the buccal ridge of bone, and twisted upon.,itself at the an-
terior border. The free end was bent into a hook for’the application of trac-
 ORTHODONTIC ANCHORAGE POSSIBILITIES IS BASAL BONE 415

tion by an elastic. Here a traction of 200 grams was applied and allowed to
act for twenty-four days, at which time the animal was sacrificed and a micro-
scopic section was made at the site of bone resorption. The steel ring had been
carried about halfway through the original bone structure which it encircled.
Since the microscopic findings are being more fully st>udied in work now in
progress, they will not be discussed here.
Dog 2 was reused (second test) to study the reaction to a steel ring in
the ramus of the mandible as in Dog 5 (second test). The ring developed some
looseness and caused more soreness than when a screw was used. It came out
and was lost in fourteen days. Eighteen days after the ring came out, the
animal was sacrificed and the bone prepared for study. Fig. 7 shows the ramus
of this dog after the bone was cleaned and bleached. The destruction of the
bony ridge may be seen by a comparison with a normal ramus (Fig. 3). The
area may be seen in which new bone has been laid down, and there is a general
smoothing of the surfaces of the injured area.

Fig. ‘I.-Bone destruction on mandible of Dog 2, eighteen days after the ring had come out.
Compare with normal jaw (Fig. 3).

TABLE I. CONDEXSED OUTLINE OF ANIJW, EXPERIMENTATION

Vitallium Screw in Bone With TractioTL

B 224
27 R
L 11/21/44 200
140 12/ 6/457/44 16
21 Reused; movement 1 mm.
11/28/44 1/ Reused;
3 37 12/ 7/44 160 l/12/45 31 Sacrificed l/2,9/45, movement 1.5 mm.
4 25 i 12/12/44 160 l/13/45 25 Movement 1 mm. Small mandible
5 34 1, 12/15/44 160 l/13/45 29 Reused for ring test
Vita&urn Screw in Bone I7Jithozc.t Traction
6 & iii 12/16/44 None l/ 6/45 2,l Sacrificed 3/20/45
1 12/16/44 None l/ 6/45 21, Sacrificed 3/S/45
Stainless Steel Ring in Booze With Traotion
5 L l/2,0/45 200 Killed 24 Pathologic section being made
2 i”; R l/27/45 200 2/10/45 14 Sacrificed 3/l/45; 1 mm. movement

SUMMARY

In each of five dogs a screw of vitallium was placed in the anterior border
of the ramus of the mandible, one side on each dog. Traction was applied to the
screw by means of an orthodontic elastic connected to a maxillary appliance,
,411 of the screws came out in from sixteen to thirty-one days,
416 B. L. OAIKSFORTH ASD L. B. HIGLEY

In two dogs vitallium screws were placed in t,he rami, one side only, and
no traction applied. E,ach screw came out on the twenty-first day.
In two dogs stainless steel annealed wire rings were placed about the
anterior portion of the ramus on one side of each dog. Traction was applied
to these rings by means of elastics connected t,o maxillary appliances. One
ring came out in fourteen days. The other was loose when the animal was
sacrificed after twenty-four days. The tissue was taken for microscopic study.
Examination of the bones from sacrificed animals showed a wide destruc-
tive process after implantation of either the screws or rings in the rami.
Tooth movement was accomplished using basal bone anchorage, but an
effective force could not be maintained for more than thirty-one days in any case.

CONCLUSIOK-S

While it is hoped that some means of basal bone anchorage map be ob-
tained for orthodontic movement in the future, the results as given in this
report do not warrant its use in the manner shown here. While the tissues
of the mouth show more immunity to infect,ion than most body tissues, its
importance cannot be ignored.
It is objectionable t,o enter the Cssues surgically in the manner described
in this report, as part of an orthodontic treatment. In addition to the danger
from infection, the screws or rings do not remain stable over a period of time
which would be necessary for most orthodontic correction.
It is believed that the prompt loosening of all screws and rings placed in the
mandibles in this experiment was largely due to the communication with the
oral cavity and the resultant cont,act with the fluids and microorganisms of
that region.
The loosening of the third mandibular molar, and the perforations seen in
t,he bones examined, indicated an effort for the bone to repair itself. Todd’j
has said t,hat “A telltale vascularization indicates a site of rapid growth or
adjustment,. ” Therefore, a metal appliance placed in the manner described acts
as a foreign body, causing boric changes which would not be col:;patible with
orthodontic treatment. It is intended that further experiments shall be con-
duct,ed in which a screw of considerably smaller diameter shall be implanted,
leaving only an amount projecting past the surface of the bone for later anchor-
age attachment. The overlying Gssue mill then hc allowed to heal and thus
cover the metal screw with scar tissue which is quite resistant to infection. After
complete healing, anchorage attachment, will be made to t,he screw through a
small puncture instead of an in&ion. Stimulation of the formation of granu-
lation tissue or scar tissue before insert’ion of the wire for att,achment is made
may minimize the passage of infection to the bone.
Work is also being carried on in t,lle department at this time to design a
more efficient tissue-borne appliance which will accomplish certain ort,hodontic
movements without direct attachment to the teeth alone.

1. Angle, Edward H.: Malocclusion of the Teeth, Philadelphia, 1907, S. S. White Dental
Mfg. Co., p. 221.
2. Stuteville, 0. H.: Injuries Caused by Orthodontic Forces and the Ultimate Results of
These Injuries, ADZ. J. ORTIIODONTICS AND ORAL SURO. 24: 103, 1938.
3. Schwartz, A. M.: Tissue Changes Incident to Orthodontic Tooth Movement, INT. J.
ORTHODONTIA 18: 331, 1932.
4. Brodie, A. G., Bercea, Mary N., Gromme, E. J., Neff, C. W.: The Application of the
Principles of the Edgewise Arch in the Treatment of Class II, Division 1, Angle
Orthodontist 7: 1, 1937.
 ORTHODOXTIC ,\XCHOR.\(:E 1’OSSIBII~ITIES IS BASAI, BOr\TF: 417

5. Sved, Alexander: ,4n Appraisal of Tweecl !s Basic Principles, AX. .T. ~kTIIul)O?rTTICS ANI)
ORAL SURG. 30: 115, 1944.
6. Atkinson, Spencer R.: Orthodontics as a Life Factor, AN. J. O~mro~o~rrcs AND ORAL
SURG. 25: 1133, 1939.
7. Tweed. C. H.: Aaalication of Princinles of l%laewiee Arch in Treatment of Malor-
cl&ion, AnglcL&thodontist 11: 12: 1941. -
8. Margolis, H. L.: Axial Inclination of Mandibular Incisors, AN. J. OKTHODO~ICS AM
-ORAL 8URG. 29: 571, 1943.
9. Higley, L. B. : Cephalomrtric Diagnosis : Its Implication in Treatment, J. A. I>. A.
32: 3, 1945.
10. Shaar, C. M., and Kreuz, F. P., Jr.: Manual of Fractures, Philadelphia, 1943, P.
Blakiston’s Son & Co., pp. 3-53.
11. Bernier. J. L.. and Canhv. C. P.: Histolonic Studies on the Reaction of Alveolar Ronr
to’Vitallium Implanrs, J. A. D. A. 30:0188, 1943.
12. Brophy, T. W.: Oral Surgery, Philadelphia, 1915, P. Rlakiston’s Son & Co., pp. 641-722.
13. Venable. Charles S.. and Stuck. Walter G.: Clinical Uses of Vitallium, Philadelphia,_
1943, J. B. Lippincott Co. ’ (A paper.)
14. Berry, H. C.: A New Departure From Orthodox Methods of Setting Fractured Edentu-
lous Mandibles, J. A. D. A. 28: 388, 1941.
15. Todd, T. W.: Facial Growth ant1 Mandibular Adjustment, INT. J. ORTIIO~OWIYA 16:
1243, 1930.