The Relationship Between Jaw Posture and Muscular Strength in Sports Dentistry: A Reappraisal

Abstract

From the late 1970s until the early 1990s, there have been several reports of improved appendage muscle strength and athletic performance. Much of the criticism of using a mouthguard alone or in conjunction with a splint, such as a mandibular orthopedic repositioning appliance (MORA), to enhance athletic performance has been aimed at study designs, controls, periods of time, double blindness, and the placebo effect. Although it would appear that designing a study which pleases both clinician and researcher would be a difficult task, studies have been performed that do meet the "gold standard." The results favor the premise that jaw repositioning can enhance appendage muscular strength and athletic performance. Studies performed during the mid-1980s, and to which the scientific community refers to continually, on closer examination are flawed.

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PRACTICE,
Copyright © 1996
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ABSTRACT: From the late 1970s until the early 1990s, there have been several reports of improved
appendage muscle strength and athletic performance. Much of the criticism of using a mouthguard
alone or in conjunction with a splint, such as a mandibular orthopedic repositioning appliance (MORA),
to enhance athletic performance has been aimed at study designs, controls, periods of time, double
blindness, and the placebo effect. Although it would appear that designing a study which pleases both
clinician and researcher would be a difficult task, studies have been performed that do meet the “gold
standard.” The results favor the premise that jaw repositioning can enhance appendage muscular
strength and athletic performance. Studies performed during the mid-1980s, and to which the
scientific community refers to continually, on closer examination are flawed.
Dr. Harold Gelb received his B.S. degree
from New York University in 1944 and his
D.M.D. degree from Tufts University
College of Dental Medicine in 1947.
Currently Dr. Gelb is an Adjunct Clinical
Professor in the Department of General
Dentistry at Tufts University College of
Dental Medicine. He is founder of the
Craniomandibular Pain Center at
Tufts University College of Dental
Medicine. Dr. Gelb is a Diplomate of the
American Board of Orofacial Pain.
Dr. Noshir R. Mehta is Chairman and
Professor of General Dentistry and
Director of the Gelb Craniomandibular
and Orofacial Pain Center at Tufts
University College of Dental Medicine.
He received his D.M.D. degree and his
M.S. degree in periodontics at Tufts,
where he has been working in occlusion
research. He is a Diplomate of the
American Board of Orofacial Pain, and
a national and international lecturer.
Dr. Mehta maintains a practice limited
to periodontics and temporomandibular
disorders.
S
everal dentists who had been treating patients with
temporomandibular disorders and orofacial pain
for years, reported increased strength and perfor-
mance in their patients as a result of changing their max-
illomandibular relationships.
l-3
In the 1970s, the work of John Stenger,
4
the dentist for
the Notre Dame football team, attracted attention. He
published several articles related to mouth protection in
which he correlated some of his statistical findings on
improved strength in both football and track and field. Dr.
Stenger and several of his colleagues, namely, Drs.
Lawton, Ricketts and Wright, had published a paper ear-
lier, in 1964, in the Journal of the American Dental
Association,
5
dealing with the use of mouthguards and
documenting their relationship with cervical stress release
and postural influences. Similar results were reported by
William Osmanski, a former professional football player,
who fitted mouthguards to a specified thickness for a
group of athletes.
3
The primary goal of proponents of mouthguards was to
provide universal protection of the teeth and jaws from
trauma. Although much has been said and published
on this subject over the past 40 years, the idea that
mouthguards, mouth “protectors,” or bite appliances
could also provide some increment of increased muscle
balance, strength, and/or coordination when it surfaced
18 years ago seemed to be an intriguing idea deserving
of further research.
An article
l
which appeared 18 years ago dealt with
oral orthopedic examination and the findings related to
muscle testing of players on the Philadelphia Eagles foot-
ball team. On clinical examination, the author found a
significant number of TMD-related symptoms and made
specific correlations in this and subsequent articles. At
The Relationship Between Jaw Posture and Muscular
Strength in Sports Dentistry: A Reappraisal
Harold Gelb, B.S., D.M.D. ; Noshir R. Mehta, B.D.S., D.M.D. ;
Albert G. Forgione, Ph.D.
PHYSIOLOGY
Manuscript received
February 26, 1996; revised
manuscript received
May 21, 1996; accepted
May 21, 1996.
Dr. Harold Gelb
635 Madison Avenue
New York, New York
10022

that time, a low percentage of players surveyed (22%)
had worn nightguards. Three years later more than 85%
of the players wore mouthguards. Since that time, much
has been published relative to the necessity of wearing
mouthguards.
Athletic Performance and Jaw Posture
One of the first articles to appear on this subject was by
Stephen Smith,
l
who performed a sample study on pro-
fessional football team players with an emphasis on the
temporomandibular joint and associated musculature.
Smith ascertained that there was a correlation between
the corrected jaw posture and the ability to give a stronger
contraction. This was measured first with both the teeth
together in habitual occlusion, and then with a wax bite
position, which was fabricated by bringing the player’s
lower jaw from physiologic rest position toward the
closest speaking space with midlines evenly aligned.
The measurements were made using a Cybex II
Dynamometer in conjunction with the kinesiologic del-
toid press method.
6, 7
The Cybex data was not as signifi-
cant as first believed.
Smith was the first person to investigate Stenger’s pro-
posed relationship. In Smith’s experiment, isometric
strength in three mandibular positions was tested subjec-
tively: 1. acquired centric occlusion; 2. the wax bite posi-
tion; and 3. the position produced by an unadjusted
football mouthguard. This study was criticized later
8
for
not including a statistical analysis of the data.
However, Forgione, et al. ,
8
calculated nonparametric
statistics on Smith’s published data and found significant
differences in isometric strength of the deltoid muscles
between the three conditions. Strength while biting on the
unadjusted mouthguard was significantly greater than
while biting in acquired centric occlusion. Strength biting
on the wax bite set at the functional criterion was signifi-
cantly greater than biting on the unadjusted mouthguard.
In a later study, Smith
9
recorded strength in response to
the Isometric Deltoid Press (IDP) objectively with an
electronic strain gauge. Again, Forgione, et al.,
8
calcu-
lated statistics of the published data and found isometric
strength biting at the mandibular position, determined by
the functional criterion, to be significantly greater than
biting in acquired centric occlusion or on an unadjusted
mouthguard.
In 1980, Kaufman fabricated and positioned several
splints for the United States Olympic luge and bobsled
teams. He discovered that headaches previously reported
by luge athletes during their runs, were alleviated to
varying degrees in some of the athletes by use of these
appliances. Some of these athletes also indicated an
increase in strength when pushing off at the start.
These original findings were then followed up by a
double-blind study
10
conducted to observe the effects of
the mandibular orthopedic repositioning appliance
(MORA) on football players on the 1982 C.W. Post
College football team. Forty players were randomly
divided into two groups, one wearing the MORA
11
and
the other wearing conventional mouthpieces (CM).
12
The
players were tested primarily to discover the effects of the
MORA on performance, number, type and severity of
injuries, as well as on three measures of physical fitness:
strength, jumping ability, and balance and agility.
The overall results were positive and in favor of the
MORA. Among players using the MORA there were less
severe injuries, decreased numbers of knee injuries, and
greater strength and satisfaction. No significant findings
favored the CM. These findings highlight the importance
of the MORA to football players.
Two other studies conducted at well-known teaching
institutions showed a positive correlation between changes
in jaw relationship and increases in strength and muscle
efficiency. One study
13
showed a highly significant
increase in muscle strength and efficiency (power) of a
group of athletes as recorded by vertical jump (five per-
cent increase) and a 17.3% increase in the grip test.
However, there was no significant increase in strength
recorded for the maximum hip sled or bench press test.
The other study tested 23 athletes, and compared
mandibular position with appendage muscle strength.
Three different mandibular positions were tested, along
with all four appendages. The results indicated that
mandibular position affects appendage muscle strength
and may be important to total well-being. However, con-
siderable variability of optimum muscle strength by
muscle groups and mandibular positions was noted.
14
Another double-blind study, performed at the University
of Illinois, involved 20 randomly selected volunteer
undergraduate students.
15
The subjects were given oral
examinations, and two appliances were then constructed
for them: a MORA, which repositioned the mandible
three dimensionally, as described by Gelb,
16
and a placebo
appliance that did not alter the occlusion.
The following bite conditions were then tested for
each individual: centric occlusion, centric occlusion with
the placebo splint inserted, and the position with
the MORA inserted. Data was collected using a Cybex II
Dynamometer with the subjects seated in a stabilized
chair. The information obtained was for three bite condi-
tions: a normal bite, a normal bite with the placebo splint
inserted and a normal bite with the MORA splint inserted.
Statistically significant differences were recorded between
the MORA and normal bite conditions for shoulder
GELB ET AL. JAW POSTURE AND MUSCULAR STRENGTH
OCTOBER 1996, VOL. 14, NO. 4 THE JOURNAL OF CRANIOMANDIBULAR PRACTICE 321

extension, peak torque; shoulder extension, average
torque; and external rotation, average torque. No statisti-
cal differences were observed between the placebo and
the normal bite condition.
Charges/Countercharges
Critics of the group favoring increased strength have
contended that their work lacked:
1. Adequate controls in the research design (such as
double-blind experimental designs).
2. Proper statistical analysis.
3. Knowledge of strength testing.
On the other hand, research indicating that the maxil-
lary and mandibular orthopedic repositioning appliance
(MORA) is ineffective for strength increases has been
criticized because:
1. It did not allow adequate time for the MORA to
work.
2. The MORA will only work on subjects with TM dis-
orders or occlusal problems.
3. It is not known whether or not the appliance has
placed the mandible in its optimal physiologic rela-
tionship.
11, 17
One other early study should be mentioned, because of
inferences made that need to be corrected.
11
In this study
14 basketball players, none of whom had any clinical or
historic evidence of TMD, myofascial pain dysfunction
syndrome (MPDS) or posterior bite collapse, were tested
in a randomly assigned order with an experimental open-
ing appliance, a placebo appliance that did not alter the
mandibular position or vertical dimension, and no appli-
ance. Results clearly demonstrated there was no change
in strength among the three groups.
Interestingly, of the 14 athletes, nine were Class I;
three were Class II, subdivision 1; and two were Class II,
subdivision 2. The results of the study reportedly indi-
cated that “opening the bite” of the normal subject will
not increase upper body strength.
If one assumes the study was done as stipulated, these
authors would also agree that “opening the bite,” or just
increasing the vertical dimension of a normal subject,
will not increase upper body strength, but this bears no
relevance to the three-dimensional maxillomandibular
relationship for each individual subject. This study, like
others previously mentioned, showed a total lack of
understanding of the model analysis as described by
Lieb,
l8
or as addressed by Verban.
l9
Scientific Flaws
Although many of the earlier studies were definitely
flawed from a scientific viewpoint, from a strictly clinical
standpoint, positive changes were noted. These changes
of increased strength and performance deserved further
investigation.
Two articles which appeared in March 1984 in the
Journal of the American Dental Association warrant
mention.
20, 2l
They describe two obviously flawed studies
carried out at two universities in the same state. These
studies were later refuted by credible scientific research.
Yet, the later scientific studies were rarely mentioned at
major meetings or in succeeding studies. Only the two
obviously flawed studies were mentioned when the sub-
ject matter on which these articles were based was dis-
cussed. Is there a “double (gold) standard,” because it
serves a special group’s purpose? This double “gold”
standard denies the use of information of the utmost value
to all practitioners regardless of their specialties.
The two flawed studies reported in JADA showed little
comprehension of the procedures for fabricating appli-
ances for TMD and athletically involved patients that
have been advocated for years. Each of these studies used
treatment splints that were fabricated using the design
recommended by Gelb, but not the three-dimensional
model analysis as prescribed by Lieb,
18
which calls for
subsequent mounting on a Galetti Articulator to achieve
the corrected maxillomandibular relationship for each
subject.
In one study,
2l
the vertical dimension between the
incisors was increased by a constant 2 to 3 mm for all
subjects. None of the subjects gained or lost muscle
strength through the use of the mandibular orthopedic
repositioning appliance.
In the other study,
20
the occlusal portion of the splint
occupied the subject’s freeway space and was adjusted to
provide even contact in centric occlusion. Forty-two per-
cent of the subjects (20) had clicking in the TMJ, but
none of the subjects had palpation tenderness of the mas-
ticatory muscles or the TMJ. All subjects underwent a
chiropractic-applied kinesiologic evaluation to test iso-
metric muscle strength. This examination showed nine
subjects would benefit trom wearing a MORA. Five sub-
jects received treatment splints, and four wore placebo
splints.
This procedure is certainly questionable, since the bite
positionings were not adjusted by kinesiologic guidance
or by the chiropractor’s suggestion.
Verban
l9
summed up much of what was wrong with
these two studies in a letter to the editor published in the
July 1984 JADA. He said, “It is not the MORA, but rather
the position obtained with the MORA that is important.
This position is not universal and must be determined for
each individual. Under this hypothesis, a study in which
JAW POSTURE AND MUSCULAR STRENGTH GELB ET AL.
322 THE JOURNAL OF CRANIOMANDIBULAR PRACTICE OCTOBER 1996, VOL. 14, NO. 4

each MORA is constructed exactly the same could not
prove a benefit of statistical significance.”
Yates in the June 1984 JADA, responding to another
letter to the editor, shows his lack of understanding by
saying, “I should like to remind him that our testing pro-
cedures come from the claims of MORA supporters,
22
who show pictures in their publications indicating that
strength is increased simply by inserting the MORA.”
This could not be further from scientific reality and
indicates a lack of understanding of the actual procedures
performed.
Gaining New Perspectives
Forgione, Mehta, Westcott and McQuade
8, 23
surveyed
20 experimental and clinical studies and two review
commentaries. Their study attempted to organize what
has been reported to date; identify the inappropriate use
of terms; point out questionable statistical practices;
question the conclusions of faulty experimental designs;
and scrutinize the unfounded generalizations that have
resulted. They state that if Stenger’s original concept is
proved to be correct, it will have implications, not only
for athletic performance, but for the more central role of
occlusion in health and behavior.
In their review they found that a commentator,
24
a
reviewer,
25
and the authors of three of the studies
11, 20, 2l
made emphatic general statements critical of the original
results and several studies that followed supported
Stenger’s original proposed relationship in spite of sev-
eral factors, which they enumerated as follows:
1. Most of these experiments used subjects with no
apparent malocclusion or lack of posterior support,
and other subjects who had mixed occlusions.
2. Most researchers set bite appliances by techniques
other than kinesiological guidance, a functional tech-
nique, assuming or implying that all MORAs are
equivalent.
3. Researchers used data showing no increase in isoki-
netic tests of strength to criticize studies of isometric
strength while commenting upon “strength” unquali-
fiedly.
4. Some researchers employed either questionable sta-
tistics, experimental design or both.
5. Some authors and a commentator have invoked
placebo as a criticism of evidence that supported
Stenger’s proposal even though the placebo effect
has not been demonstrated in any of the studies that
employed a placebo control condition. The belief
that the placebo effect is omnipresent has even fos-
tered an explanation for its lack of appearance.
In addition, they mention the possible role of body test
position, and its consequent influence on the bite as it
affects results.
Their manuscript dealt not only with a review of the
current literature on variation in strength of extraoral
muscles as a function of bite relationship, but also
includes a reversal design study using a K-MORA (kine-
siologically determined using the isometric strength of
the deltoid muscle), a deflection appliance, and a placebo
appliance.
8, 23
In this study of the effect on isometric strength of
biting on three different intraoral devices and habitual
occlusion, it was concluded that a relationship does exist
between bite and isometric strength. They also found that
the previous speculation concerning the role of the
placebo effect was not substantiated by the data gathered
in their experiment.
The Female Experience
A methodologically refined replication of Smith’s
experiment was performed by Fuchs
26
in 1981. This
unpublished dissertation compared isometric strength of
40 females divided equally into five groups; TMJ patients,
athletic TMJ-symptomatic subjects, sedentary TMJ-
symptomatic patients, normal athletic subjects, and
normal sedentary subjects. Identical with Smith’s experi-
ments, a wax bite was fabricated for each subject guided
by the IDP. But unlike Smith’s research design, a disoc-
cluded and a placebo condition were both included. The
strength of six body parts (left and right arm, left and
right foot, upper and lower body) were measured under
four bite conditions: 1. mouth open 3 mm; 2. bite in
acquired centric; 3. K-MORA, an intra-oral device that
supports a mandibular position determined by a func-
tional criterion, which is a locking response to the IDP, a
muscle challenge used by kinesiologists; and 4. bite with
a placebo wax buccal device. An electronic strain gauge
identical with that employed by Smith
9
recorded responses
in kilogram/second with the analog output simultane-
ously recorded on the stripchart of a Beckman Dynograph.
Mean strength scores for the whole sample were found to
be markedly different. Tukey’s multiple comparison
technique showed no significant differences among
mouth open, acquired centric, and placebo conditions.
Greater strength was obtained with the K-MORA than in
all the other conditions. For the lower body, a significant
difference in strength was obtained between the
K-MORA and the mouth open. Similarly, the K-MORA
strength was greater than the placebo in the upper body
and left foot even though the K-MORA performance was
stronger than habitual occlusion in only the right arm and
left foot. Fuchs then concluded that with no exception,
GELB ET AL. JAW POSTURE AND MUSCULAR STRENGTH
OCTOBER 1996, VOL. 14, NO. 4 THE JOURNAL OF CRANIOMANDIBULAR PRACTICE 323

the strength means were greater and the standard devia-
tions lower in the K-MORA position than in any other
position. Fuchs replication of Smith’s research helps
answer the unchallenged placebo criticisms in the litera-
ture that tend to obviate Stenger’s and Smith’s seminal
findings prematurely.
A double-blind study (Abduhl Jabbar, et al., 1994)
27
was designed to test the bilateral isometric strength of the
extremities and shoulder girdle of female TMD patients.
The patients all demonstrated obvious loss of vertical
dimension of occlusion by a deep overbite occlusion,
missing posterior supporting teeth or obvious tooth wear
due to bruxism or repeated occlusal adjustments. The
strength testing was carried out at the Neuromuscular
Disease Research Laboratory of the Department of
Neurology at the Tufts New England Medical Center, an
independent medical facility, using the apparatus and
procedures
28, 29
routinely used to assess the isometric
strength of patients with neuromuscular disease.
A standard neuromuscular test with the Maximal
Voluntary Isometric Contraction apparatus was used to
assess strength of right and left shoulder, elbow and knee
flexion and extension, as is routinely performed with all
neuromuscular disease patients. Twelve strength tests
were carried out for each of three conditions: 1. Baseline,
biting in habitual occlusion; 2. Elevated, biting on a
K-MORA; 3. Placebo, biting with the placebo appliance
inserted. The order of conditions 2 and 3 was counterbal-
anced without knowledge of the subjects.
Twelve repeated measures ANOVAs (each subject as
their own control) were conducted for each of the 12
strength measures. All F-tests indicated a significant
main effect for treatment differences (p<0.0001). Mean
strength biting on the K-MORA was consistently greater
(p<0.001) than baseline or placebo strength. Baseline and
placebo conditions were equivalent.
These findings confirm observations that individuals
with loss of vertical dimension of occlusion respond to a
bite-raising appliance by increased isometric strength.
Isometric strength of the sternocleidomastoid muscles
(SCM) was assessed in 15 subjects demonstrating deep
bite and loss of vertical dimension by al-Abasi, et al.
30
In
the preliminary part of the experiment all subjects were
tested sitting, with the head unsupported and the teeth 1.
disoccluded and 2. biting in habitual occlusion. Strength
with the teeth disoccluded was significantly greater than
biting in habitual occlusion. Four types of acrylic lower
appliances were then fabricated:
1. Habitual bite, elevated to the functional criterion of
the IDP. (This vertical dimension was transferred
to an articulator and three other appliances were
fabricated at the same vertical dimension. )
2. Edge-to-edge.
3. Retruded.
4. Lateral shift of l mm to the left.
Each subject was tested twice, biting with and without
appliance in habitual occlusion, edge-to-edge, retruded
and lateral shift positions. Analysis of variance showed a
significant difference between groups. The mean stern-
ocleidomastoid muscle (SCM) strength of 27.17 lbs.
obtained when biting in all the elevated vertical positions
was greater than 21.73 lbs. obtained biting without a bite
elevating appliance.
More detailed analysis showed:
1. Without an appliance, SCM strength, biting in habit-
ual occlusion, was lower than in the edge-to-edge
position but not in the retruded and lateral shift posi-
tions; and
2. With appliances, SCM strength of the same subjects
was greater in habitual and edge-to-edge positions
than in retruded but not lateral shift positions.
The findings indicated that, while biting at an elevated
position determined by the IDP, SCM isometric strength
can increase regardless of position. However, an elevated
edge-to-edge position and an elevated habitual position
maximized SCM isometric strength.
Far Eastern Contributions
Researchers in Korea and Japan have taken an interest
recently in this relationship between vertical dimension
of occlusion and muscle strength. The effect of a bite-ele-
vating appliance on back muscle strength of 22 male foot-
ball players and 22 female archers was tested by Kang
and Lee.
31
Both groups of athletes and a control group
were tested using a digital back muscle dynamometer
before and after 30 days of appliance wear. Back muscle
strength increased with the bite-elevating appliance
(15.2% in males and 12.4% in females), but the control
group’s mean strength did not change.
Tsukimura
32
tested back strength of eight subjects at
different vertical dimensions. In the disoccluded mandibu-
lar position, back strength was the weakest, but tended
not to increase as a 2, 5 and 10 mm splint was worn and
decreased when a 15 mm appliance was worn. Maximum
strength was obtained in the 2-10 mm range of splinting.
Yokobori and Horii
33
performed the critical experi-
ment supporting the contention of Forgione, et al.,
8
that
isokinetic and isometric strength may not be related.
Forty college athletes were fitted with bite-elevating
appliances and tested on both isometric and isokinetic
tasks, with and without the appliance. With the appliance,
significant increases in isometric strength were obtained
in back extension, leg extension, and plantar extension,
JAW POSTURE AND MUSCULAR STRENGTH GELB ET AL.
324 THE JOURNAL OF CRANIOMANDIBULAR PRACTICE OCTOBER 1996, VOL. 14, NO. 4

GELB ET AL. JAW POSTURE AND MUSCULAR STRENGTH
OCTOBER 1996, VOL. 14, NO. 4 THE JOURNAL OF CRANIOMANDIBULAR PRACTICE 325
but not in arm flexion and grip strength. Isokinetic
strength of knee extension and flexion showed no differ-
ence when tested on a Cybex at angular velocities of 60,
120 and 240 deg/s. Interestingly, these authors also found
that equilibrium was improved in these subjects while
wearing the appliances.
A study presented last year
34
suggested that wearing
appropriate complete dentures is essential to not only
the restoration of masticatory function, but also the main-
tenance of the ability of physical exercise. A previous
study done by the same investigators suggested that the
occlusal support played an important role for the normal
dentate subjects who exhibited teeth clenching during
physical exercise. Since the occlusal support is obtained
by wearing complete dentures in edentulous patients,
physical exercise should be affected whether wearing
dentures or not.
Summary
The clash that exists between the clinician and some
scientists is becoming ever more visible as the differ-
ences between applied and basic biological research
narrow, and the time lag between a fundamental discov-
ery and clinical application shrinks. In a number of cases,
the opposite can be true. It is no surprise that
clinical application of value to the patient may outstrip
scientific verification because of differences in training
and individual interests. Scientists spend five to ten years
of postgraduate training learning how to conduct proper
research, whereas physicians devote the bulk of their
training to patient care. This also holds true for dentists.
35
The time has finally come for dental clinicians
and scientific researchers to develop greater mutual
respect, thereby providing better and more cost-effective
care to our patients sooner and with less suffering.
References
1. Smith S: Muscle strength correlated to jaw posture and the temporomandibu-
lar joint.
NY State Dent J 1978; 444:278-285
2. Schwartz R, Novich M: The athlete’s mouthpiece.
Am J Sports Med 1980;
8:357
3. Kaufman RS: Case reports of TMJ repositioning to improve scoliosis and the
performance by athletes.
NY State Dent J 1980; 46:206
4. Stenger JM: Physiologic dentistry with Notre Dame athletes.
J Amer Acad
Physiologic Dent - Basal Facts
, Spring 1977
5. Stenger JM, Lawton EA, Ricketts J, Wright JM: Mouthguards - protection
against shock to head, neck and teeth.
JADA 1964; Vol. 19
6. Eversaul GA: Biofeedback and kinesiology: technologies for preventive den-
tistry.
J Am Soc Prevent Dent 1976; 6:19
7. Goodheart GJ: Kinesiology and dentistry.
J Am Soc Prevent Dent 1976; 6:16
8. Forgione AG, Mehta NR, McQuade CF, Westcott WL: Strength and bite. Part
1: An analytical review.
J Craniomand Pract 1991: 9(4): 305-315
9. Smith SD: Adjusting mouthguards kinesiologically in professional football
players.
NY State Dent J 1982; 48:298-301
10. Kaufman A, Kaufman, RS: An experimental study on the effects of the
MORA on football players.
J Amer Acad Physiologic Dent - Basal Facts
1983; Vol. 6:4
11. Greenberg MS, Cohen SG, Springer P, Kotwick, JE, Vegso JJ: Mandibular
position and upper body strength: a controlled clinical trial.
JADA 1981;
103:576
12. Moore M: Corrective mouthguards: Performance aids or expensive placebos?
Physician Sports Med 1981; 9:127
13. Bates RF, Atkinson WB: The effects of maxillary MORA’s on strength and
muscle efficiency tests.
J Craniomand Pract 1983; 1:37
14. Williams MO, Chaconas SJ, Bader P: The effect of mandibular position on
appendage muscle strength.
J Prosthet Dent 1983; 49:560
15. Verban EM, Jr, Groppel JL, Pfautsch MS, Ransmeyer GC: The effects of a
mandibular orthopedic repositioning appliance on shoulder strength.
J Craniomand Pract 1984; 2(3):232-237
16. Gelb H, ed.:
Clinical Management of Head, Neck and TMJ Pain and
Dysfunction.
Philadelphia: W.B. Saunders, 1977
17. Burkett LW, Bernstein A: Strength testing after jaw repositioning with a
mandibular orthopedic appliance.
Physician Sports Med 1982;10:101
18. Lieb MM: Oral Orthopedics in Gelb, H. (ed.)
Clinical Management of Head,
Neck and TMJ Pain and Dysfunction
. Philadelphia, W.B. Saunders, 1977
19. Verban EM, Jr: MORA Stats, in Letters to the Editor.
JADA 1984; 109:17
20. Schubert MM, Guttu RL, Hunter LH, Hall R, Thomas R: Changes in shoul-
der and leg strength in athletes wearing mandibular orthopedic reposition-
ing appliances.
JADA 1984; 108:334-337
21. Yates JW, Koen TJ, Semenick DM, Kuftinec MM: Effect of a mandibular
orthopedic repositioning appliance on muscular strength.
JADA 1984;
108:331-333
22. Gelb H: Multi-disciplinary management of the craniomandibular syndrome.
NY State Dental J 1980; 42(4):190-195
23. Forgione AG, Mehta NR, McQuade CF, Westcott WL: Strength and bite. Part
II: Testing isometric strength using a MORA set to a functional criterion.
J Craniomand Pract 1992; 10(1):13-20
24. Jakush J: Divergent views: Can dental therapy enhance athletic performance?
JADA 1982; 104(3):292-298
25. Chiodo GT, Rosenstein DI: Mandibular orthopedic repositioning appliance
and athletic performance.
JODA 1986; Winter:31-33
26. Fuchs CZ: The effect of the temporomandibular joint position on isometric
muscle strength and power in adult females. [Ph.D. Thesis]. Department of
Education. Boston University, 1981 ____ p.
27. Jabbar T, Mehta N, Forgione A, et al.: Relation between mandibular position
and strength of extremities.
J Dent 1994, Res 73 [IADR Abstracts]
p. 114 #103
28. Andres PL, Hedlund W, Finison L, Conlon T, Munsatt TL: Quantitative
motor assessment in amyotrophic lateral sclerosis.
Neurology 1986;
36:937-941
29. Munsatt TL, Andres PL, Finson L, Conlon T, Thibodeau L: The natural his-
tory of motoneuron loss in amyotrophic lateral sclerosis.
Neurology 1988;
38:409-413
30. Al-Abbasi H, Mehta N, Forgione A, Clark E: Effect of vertical dimension and
mandibular position on sternocleidomastoid strength.
J Dent Res 1995,
[AADR Abstracts] 74:29
30. Kang KW, Lee SW: The effects of mandibular orthopedic repositioning
appliance (MORA) on back muscle strength and attention focusing.
J Dent
College Seoul Natl Univ
1988; 12:217-230
32. Tsukimura N: Study on the relation between the stomatognatic system and
systemic condition - Influences of postural changes in vertical maxillo-
mandibular relation on back strength.
J Jpn Prosthodont Soc 1992; 36:705-
719
33. Yokobori D, Horii A: Effects of wearing splints on muscle strength and equi-
librium in athletes.
Jpn J Phys Fitness Sports Med 1993; 42:2885-291
34. Ishijima T, Hirai T, Koshino H, Konishi Y, Yokoyama Y (Health Sciences
University of Hokkaido School of Dentistry): Relationship between
occlusal support and physical exercise in edentulous patients. [Abstracts]
73rd General Session IADR June 28 to July 1, 1995 Singapore.
JDR Vol.
74 Special Issue
35. Gelb H: A too-polite silence about shoddy science: dynamic strength testing
and beyond. J Craniomandib Pract 1992; 10(1):75-79
Dr. Albert G. Forgione is Chief Clinical Consultant of the Gelb
Craniomandibular and Orofacial Pain Center and Associate Clinical
Professor of Psychology at Tufts University School of Dental Medicine.
He received his Ph.D. at Boston University where he did research in
psychophysiology and behavioral psychology. He joined the faculty of
Tufts in 1972 where he taught behavioral medicine and hypnosis.
Together with Dr. Mehta, he started the TMJ Center at Tufts in 1979.