This document provides an overview of the muscles of mastication, including their development, classification, anatomy, nerve and blood supply, actions, and clinical relevance. It describes the eight main muscles - masseter, temporalis, lateral pterygoid, and medial pterygoid. Disorders affecting the masticatory muscles are also outlined. The document contains detailed sections on each individual muscle.

2. Muscles of Mastication

3. CONTENTS
1) Introduction
2) Development
3) Classification
4) The masseter muscle
5) Temporal fascia
6) The temporalis muscle
7) The lateral pterygoid muscle
8) The medial pterygoid muscle

4. 9) Disorders of masticatory muscles
a) Local myalgia
b) Myofascial pain
c) Centrally mediated myalgia
d) Myospasm
e) Myositis
f) Myofibrotic contracture
g) Masticatory muscle neoplasia
h) Persistent orofascial muscle pain (POMP)

5. 10)Clinical examination of the patient
11) Questions regarding oral behaviour and parafunction.
12) Treatment
a) Passive stretching
b) Physiotherapy
c) Splint therapy
d) Pharmacologic therapy
13) Studies
14)References

6. INTRODUCTION
• Muscle is the tissue of the body which primarily functions as a source of power.
There are three types of muscle in the body. Muscle which is responsible for
moving extremities and external areas of the body is called "skeletal muscle."
Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and
bowel is called "smooth muscle”. (William C. Shiel Jr 2016)
• Mastication is the process of grinding and chewing food into smaller pieces in
the oral cavity of the head turning it into a food bolus. This mass can then be
swallowed with ease and further digested as it passes along the alimentary canal.
• Apart from the teeth and the tongue, certain muscles known as
the masticatory muscles partake in specific movements of
the temporomandibular joint (TMJ) during this process to allow the initial stages
of digestion to occur.

7. DEVELOPMENT
• The muscles of
mastication
develop from the
mesoderm of the
first pharyngeal
arch, and are
supplied by the
mandibular nerve
which is the nerve
of that arch.

8. CLASSIFICATION
• The masticatory muscles have been classified in various ways
based on the findings of human anatomical, comparative
anatomical, and embryological examinations.
• In some reports, the masticatory muscles have been classified into
LATERAL AND MEDIAL GROUPS in relation to the position to the
mandible, with the lateral group consisting of the masseter and
temporalis, and the medial group consisting of the lateral and
medial pterygoid muscles (Lewis, 1910; Paturet, 1964; Rayne and
Crawford, 1971; Reuter, 1897; Romer, 1962; Sappey, 1876).

9. • In other studies, the muscles have been classified into LATERAL
AND MEDIAL GROUPS according to the positional relationship to
the main trunk of the mandibular nerve, with the lateral group
consisting of the masseter, temporalis, and lateral pterygoid, and
the medial group consisting of the medial pterygoid
(Gegenbaur, 1903; Edgeworth, 1914; Lubosch, 1938; Terada and
Sato, 1982; Tomo, 1990; Tomo et al., 1993).

10. • According to Dr Daniel J Bell
and Frank Gaillard et al.
the muscles of
mastication can be divided
into primary and secondary
groups according to whether
they connect the mandible
directly to the skull or if they
attach to other structures in
the neck, e.g. hyoid, thyroid
cartilage.
PRIMARY
• Masseter
• Temporalis
• Medial pterygoid
• Lateral pterygoid
SECONDARY
• Suprahyoid
• Digastric
• Mylohyoid
• Geniohyoid
• Buccinator

11. The Masseter
• It is a quadrilateral muscle, consisting of two portions, superficial and deep.
• The superficial portion, the larger, arises by a thick aponeurosis from the
zygomatic process of the maxilla, and from the anterior two-thirds of the
lower border of the zygomatic arch; its fibers pass downwards and
backwards, to be inserted into the angle and lower one-half of the lateral
surface of the ramus of the mandible.
• The deep portion is much smaller and is partly concealed by the superficial
portion; it arises from the posterior one-third of the lower border and from
the whole of the medial surface of the zygomatic arch; its fibers pass
almost vertically downwards to be inserted into the lateral surfaces of the
coronoid process and the upper one-half of the ramus of the mandible.

12. Relations
• Superficial to the muscle are the
integument, the Platysma, the
Risorius, the Zygomaticus major,
and the parotid gland; the
parotid duct, branches of the
facial nerve, and the transverse
facial vessels cross the muscle.
• The deep surface is in relation
with the insertion of the
Temporal muscle and the ramus
of the mandible; a mass of fat
separates it from the Buccinator
muscle and the buccal nerve.

13. • The masseteric nerve and artery reach the deep surface of the
muscle bypassing through the posterior part of the mandibular
notch. The posterior margin is overlapped by the parotid gland;
the anterior margin projects over the Buccinator and is crossed
below by the anterior facial vein.

14. Nerve supply
• The Masseter is supplied by
Massetric nerve which is a
branch of the anterior trunk of
the mandibular nerve.
Masseteric Nerve

15. Blood supply
• The masseter muscle is
supplied with blood by
the masseteric artery, a
branch of the maxillary artery.
Masseteric Artery

16. Actions
• The Masseter pulls the
mandible towards and against
the maxillae; from its relation
to the axis of movement it can
act with very great force.

17. Clinical aspects
MASSETER (MANDIBULAR) REFLEX
• The routine neurological examination includes testing of the jaw jerk
reflex, also known as the masseter or mandibular reflex. The examiner
places his index finger on the chin of the patient and taps the finger with
the reflex hammer. In healthy people, the stretch of the masseter
provokes an upward movement of the mandible.
• In order to produce better results, it is helpful to ask the patient to relax
and slightly open his or her mouth and close the eyes. A pathological jaw
jerk reflex can indicate a lesion of the trigeminal nerve but if this seems
rather unlikely (e.g. intact facial sensation, well developed masseter
muscles on both sides etc.), one has to consider a brainstem lesion.

18. INFECTIONS AND SUBMASSETERIC ABSCESSES
• Under some conditions, specifically while infected with the
bacteria Clostridium tetani, strong and persistent spasms of the masseter
muscle can occur. That kind of contraction is called trismus, and can
interfere with the normal feeding process.
• Since the masseter muscle is involved with submasseteric space, it has an
important role when it comes to submasseteric abscesses. These abscesses
are relatively rare, so they are easily confused with parotid gland
infections.
• The origin of the infection is usually odontogenic, from pericoronitis in the
mandibular third molar, especially when the apices of the tooth lies very
close to or within the space. As a result, the infection typically spreads
easily to this region where these abscesses tend to be chronic.

19. • A major hallmark of a submasseteric space infection is the upper
mentioned trismus, so the masseter is actually sending signals that the
infection is all about submasseteric space instead of any surrounding
structures.
• By knowing the relations and functions of the masseter muscle, we
can easily narrow down our differential diagnosis options for the patient
who is suffering from some form of facial lesion.

20. TEMPORAL FASCIA
• The temporal fascia covers the Temporal
muscle. It is a strong, fibrous investment,
covered, laterally, by the Auriculares
anterior et superior, the epicrainal
aponeurosis, and part of the Orbicularis
oculi.
• The superficial temporal vessels and the
auriculotemporal nerve cross it from below
upwards. Above, it is a single layer,
attached to the entire extent of the
superior temporal line; below, it consists of
two layers, one of which is attached to the
lateral, and the other to the medial border
of the zygomatic arch.

21. • A small quantity of fat, the
zygomatic branch of the
superficial temporal artery, and
the zygomaticotemporal branch
of the maxillary nerve, are
contained between these two
layers. The deep surface of the
fascia affords attachment to the
superficial fibers of the
Temporalis.

22. The Temporalis Muscle
• The Temporalis is a fan-shaped muscle,
situated at the side of the head. It arises
from the whole of the temporal fossa
(except the portion formed by the
zygomatic bone) and from the deep surface
of the temporal fascia.
• Its fibers converge as they descend, and
end in a tendon which passes through the
gap between the zygomatic arch and the
side of the skull, and is inserted into the
medial surface; apex, and anterior border
of the coronoid process, and the anterior
border of the ramus of the mandible nearly
as far forwards as the last molar tooth.

23. • Superficial to the muscle are the
skin, the Auriculares anterior et
superior, the temporal fascia, the
superficial temporal vessels, the
auriculotemporal nerve, the
temporal branches of the facial
nerve the zygomaticotemporal
nerve, the epicranial
aponeurosis, the zygomatic arch,
and the Masseter.
Relations

24. • The deep surface is in relation
with the temporal fossa, the
Lateral pterygoid and part of
the Buccinator the maxillary
artery and its deep temporal
branches, the deep temporal
nerves, and the buccal vessels
and nerve. Behind the tendon
of the muscle the vessels and
nerve to the Masseter traverse
the mandibular notch. The
anterior border is separated
from the zygomatic bone by a
mass of fat.

25. Nerve supply
• The Temporalis is supplied by
the deep temporal branches of
the anterior trunk of the
mandibular nerve.

26. Blood supply
• It is supplied by anterior
deep temporal and
posterior deep temporal
arteries which are the
branches of ECA.

27. Actions
• The Temporal muscle elevates
the mandible and so closes the
mouth. This movement requires
both the upward pull of the
anterior fibers and the
backward pull of the posterior
fibers, because the head of the
mandible rests on the articular
eminence when the mouth is
open. The posterior fibers draw
the mandible backwards after it
has been protruded.

28. Clinical aspects
• Tension of the temporal muscle can induce pain in the temporal area.
Common causes include:
• misalignments of the teeth and jaws
• trauma
• a prolonged immobilisation (e.g. after a mandibular fracture)
• teeth grinding (bruxism)
• a dental intervention during which the person's mouth had to be open for a long period
of time.

29. The Lateral Pterygoid Muscle
• The Pterygoideus lateralis (Pterygoideus
externus) is a short, thick muscle, somewhat
conical in form.
• It arises by two heads: an upper from the
infratemporal surface and infratemporal crest of
the greater wing of the sphenoid bone; and a
lower from the lateral surface of the lateral
pterygoid plate.
• Its fibers pass backwards and laterally, to be
inserted into a depression on the front of the
neck of the mandible, and into the articular
capsule and disc of the mandibular articulation.

30. Relations
• Its superficial surface is in relation with
the ramus of the mandible, the maxillary
artery, which crosses it, the tendon of the
Temporal muscle and the Masseter.
• Its deep surface rests against the upper
part of the Pterygoideus medialis, the
sphenomandibular ligament, the middle
meningeal artery, and the mandibular
nerve; its upper border is in relation with
the temporal and masseteric branches of
the mandibular nerve; its lower border
with the lingual and inferior dental
(alveolar) nerves.

31. • The buccal (buccinator) nerve
and the maxillary artery pass
between the heads of the
muscle.
• The artery often lies deep to
the muscle.

32. Nerve supply
• The Lateral pterygoid muscle
is supplied by a branch from
the anterior trunk of the
mandibular nerve.

33. Blood Supply
• The lateral pterygoid muscle
receives blood supply from the
pterygoid branch of the second
part of the maxillary artery.

34. Actions
• The Lateral pterygoid muscle assists in
opening the mouth, by pulling forward
the condyloid process of the mandible
and the articular disc, while the body
of the mandible is being depressed by
the suprahyoid muscles. Acting with
the Medial pterygoid muscle it
protrudes the mandible so that the
lower incisors are projected in front of
the upper.

35. Clinical Aspect
• The spasm of the lateral pterygoid muscle can be very painful and
can result in trismus (locked jaw). The patient may require
analgesics or muscle relaxants for treating the same.
• Some authors believe that during temporomandibular disorders,
this muscle plays an important role. This involvement may be due
to the absence of coordination between the superior and the
inferior bellies of the muscle. This lack of coordination leads to
disturbance in the horizontal positioning of the intra-articular disc
relative to the condyle. (Juniper RP 1984)

36. • Clinical examination of patients with such disorders exhibits pain
in the region of this muscle during jaw movements and during
palpation behind the tuberosity region. (Murray GM et al 2004)
• In the internal derangement of the temporomandibular joint,
there are implications that the superior belly of lateral pterygoid
muscle plays a role in causing anterior dislocation of the disk
(Taskaya-Yilmaz N et al 2005). The prolonged contraction of the
muscle places forward traction on the disk resulting in anterior
displacement of the disk

37. THE MEDIAL PTERYGOID MUSCLE
• The Pterygoideus medialis (Pterygoideus
internus), a thick, quadrilateral muscle,
arises from the medial surface of the
lateral pterygoid plate, and from the
grooved surface of the tubercle (pyramidal
process) of the palatine bone; it has also a
more superficial slip of origin which arises
from the lateral surfaces of the tubercle
of the palatine bone and tuberosity of the
maxilla, and lies at first on the surface of
the lower part of the lower head of the
Lateral pterygoid muscle.

38. • Its fibers pass downwards, laterally,
and backwards, and are inserted, by
a strong tendinous lamina, into the
lower and back part of the medial
surfaces of the ramus and angle of
the mandible, as high as the
mandibular foramen.

39. Relations
• The lateral, surface of the muscle is in
relation with the .ramus of the
mandible, from which it is separated, at
its upper part, by the Lateral pterygoid,
the sphenomandibular ligament, the
maxillary artery, the inferior dental
vessels and nerve, the lingual nerve,
and a process of the parotid gland. The
medial surface is in relation with the
Tensor palati, and is separated from the
Superior constrictor of the pharynx by
the Styloglossus, the Stylopharyngeus
and some areolar tissue.

40. Nerve supply
• The Medial
pterygoid muscle
is supplied by a
branch from the
mandibular nerve.

41. Blood Supply
• Medial pterygoid muscle
receives blood supply from
pterygoid and buccal branches
of maxillary artery. To a lesser
extent, ascending palatine
artery and muscular branches
of facial artery also contribute
to the blood supply of this
muscle.

42. Actions
• The Medial pterygoid muscle assists in
approximating the mandible to the
maxillae. Acting with the Lateral
pterygoid it protrudes the mandible,
When the two Pterygoid muscles of one
side are in action, the corresponding side
of the mandible is drawn forwards, while
the head of the mandible on the opposite
side remains comparatively fixed; by an
alternating action of the muscles of the
two sides, the side-to-side movements,
such as take place during trituration of
the food, are effected.

43. Clinical Significance
• The medial pterygoid muscle along with masseter muscle forms a
'pterygomassetric sling' that suspends the mandible. After orthognathic
surgery to treat mandibular prognathism, this sling greatly affects the
stability of the two segments of the mandible. Also, the healing process of
bone between the two segments (distal and proximal) is subject to
influence by the magnitude of force applied by the sling. (Batra P et al
2006)
• Infection in the mandibular teeth more frequently involves the lower
compartment of the masticatory space, which contains medial pterygoid
muscle; this could result in pterygoid muscle abscess. Since both masticator
space and infratemporal fossa share the medial pterygoid muscle, there are
chances of the potential spread of infection from this space to the
infratemporal fossa.

44. • Sometimes, an occlusal interference may occur due to movement of the
accessory medial pterygoid muscle, which is clinically evident on the
buccal cusps of the third molar. This occlusion abnormality may act as a
trigger point for spasm of the muscle, which can be clinically checked by
fixing the mandible under pressure in the most posterior and centric
position to make the interfering occlusal contacts evident. (Sakamoto Y &
Akita K 2004)
• During vertical jaw movements, lateral pterygoid muscle act as a primary
muscle that generates horizontal forces. However, the medial pterygoid
muscle may also play a role in controlling horizontal jaw positions. (Chen H
et al 2017)

45. • The Pterygospinous ligament, which is occasionally replaced by
muscle fibers, stretches between the spine of the sphenoid bone
and the posterior border of the lateral pterygoid plate near its
upper end. It is sometimes ossified and they help to bound a
foramen which transmits the branches of the mandibular nerve
destined for the Temporal, Masseter and Lateral pterygoid
muscles.

46. DISORDERS OF MASTICATORY MUSCLES
• Muscle disorders involving the masticatory muscles have been
considered analogous to skeletal muscle disorders throughout the
body.(Waltimo A et al 1993, Scrivani SJ et al 2008)
• Mechanisms behind masticatory muscle pain include overuse of a
normally perfused muscle or ischemia of a normally working
muscle, sympathetic reflexes that produce changes in vascular
supply and muscle tone, and changes in psychological and
emotional states. (Nijs J et al 2012)

47. • Chronic myalgia of the muscle of mastication (MOM) is one aspect of
temporomandibular disorders (TMDs). (Nijs J et al 2012, Benoliel R et al
2011) Historically, clinicians and researchers have subclassified TMDs into
intracapsular disorders and masticatory muscle disorders such as
• local myalgia,
• myofascial pain,
• centrally mediated myalgia,
• myospasm,
• myositis,
• myofibrotic contracture, and
• masticatory muscle neoplastic disease. (Dworkin SF & LeResche L. 1992)

48. The clinical features of masticatory muscle
disorders are as follows
LOCAL MYALGIA
• Sore MOM with pain in cheeks and temples on chewing, wide
opening, and often on waking (eg, nocturnal bruxism)
• Bilateral
• Described as stiff, sore, aching, spasm, tightness, or cramping
• Sensation of muscle stiffness, weakness, fatigue
• Possible reduced mandibular range of motion
• Differential diagnosis: myositis, myofascial pain, neoplasm,
fibromyalgia

49. Myofascial Pain
• Regional dull, aching muscle pain
• Trigger points present and pain referral on palpation with/without
autonomic symptoms
• Referred pain often felt as headache
• Trigger points can be inactivated with local anesthetic injection
• Sensation of muscle stiffness and/or malocclusion not verified
clinically

50. • Otologic symptoms including tinnitus, vertigo, and pain
• Headache or toothache
• Decreased range of motion
• Hyperalgesia in region of referred pain
• Differential diagnosis: arthralgia, myositis, local myalgia,
neoplasia, fibromyalgia

51. Centrally Mediated Myalgia
• Trigger points and pain referral on palpation
• Sensation of muscle stiffness, weakness, and/or fatigue
• Sensation of malocclusion not verified clinically
• Otologic symptoms including tinnitus, vertigo, and pain
• Decreased range of motion
• Hyperalgesia
• No response to treatment directed at painful muscle tissue
• Differential diagnosis: arthralgia, myositis, myofascial pain, local
myalgia, neoplasm, fibromyalgia

52. Myospasm
• Sudden and involuntary muscle contraction
• Acute malocclusion (dependent on muscles involved)
• Decreased range of motion and pain on function and at rest
• Relatively rare disorder in orofacial pain population
• Differential diagnosis: myositis, local myalgia, neoplasm

53. Myositis
• History of trauma to muscle or source of infection
• Often continuous pain affecting entire affected muscle
• Pain aggravated by function
• Severe limited range of motion

54. Myofibrotic Contracture
• Not usually painful
• Often follows long period of limited range of motion or disuse
(eg, intermaxillary fixation)
• History of infection or trauma is common
• Differential diagnosis: TMJ ankylosis, coronoid hypertrophy

55. Masticatory Muscle Neoplasia
• Pain may or may not be present
• Anatomic and structural changes: tumors may be in muscles or
masticatory spaces
• Swelling, trismus, paresthesias, and pain referred to teeth
• Positive findings on imaging or biopsy

56. PERSISTENT OROFACIAL MUSCLE PAIN
(POMP)
• Recently a new term, PERSISTENT OROFACIAL MUSCLE PAIN
(POMP), has been introduced, to more accurately reflect the
interplay between peripheral nociceptive sources in muscles,
faulty central nervous system components, and decreased coping
ability. (Benoliel R et al 2011)
• POMP likely shares mechanisms with tension-type headache,
regional myofascial pain, and fibromyalgia, and has genetically
influenced traits that determine pain modulation and
pharmacogenomics interacting with psychological traits to affect
disease onset, clinical progression, and pain experience. (Benoliel
R et al 2011, Benoliel R & Sharav Y 2010)

57. CLINICAL EXAMINATION OF THE PATIENT
• The most effective approach for the diagnosis of masticatory muscle
pain involves careful review of the chief complaint, the history of the
present illness, the dental, medical, and psychosocial behavioral
histories, and a comprehensive evaluation of the head and neck
including a cranial nerve assessment. (Scrivani SJ ET AL 2008)
• In addition, imaging modalities may be important in ruling out other
conditions.
• No one physical finding can be relied on to establish a diagnosis; rather,
a pattern of abnormalities may suggest the source of the problem and
diagnosis. (Mohl ND. 1999)
• However, masticatory muscle tenderness on palpation is the most
consistent examination feature present in TMDs. (Schiffman E et al 1989,
Lipton JA et al 1993, Kurita K et al 1998, Milam SB 2006, Rammelsberg P
et al 2003, Clark GT 1989)

58. • In fact, the clinical features that distinguish patients from non-
TMD or masticatory muscle pain most consistently reported in the
literature are: restricted passive mouth opening without pain;
masticatory muscle tenderness on palpation; limited maximal
mouth opening; and an uncorrected deviation on maximum mouth
opening and tenderness on muscle or joint palpation. (Scrivani SJ
et al 2008, Schiffman E et al 1989, Lipton JA et al 1993, Kurita K
et al 1998, Milam SB. 2006, Rammelsberg P et al 2003, Clark GT
et al 1989)

59. Questions regarding oral behavior and
parafunction
DO YOU:
• Clench or grind your teeth when asleep?
• Sleep in a position that puts pressure on your jaw? (eg, side, stomach)
• Clench or press teeth together while awake?
• Touch or hold teeth together while eating?
• Hold, tighten, or tense muscles without clenching or touching teeth
together?
• Hold out or jut jaw forward or to side?
• Press tongue between teeth?
• Bite, chew, or play with tongue, cheeks, or lips?

60. • Hold jaw in rigid or tense position to brace or protect jaw?
• Bite or hold objects between teeth (eg, pens, pipe, hair, fingernails, and so forth)?
• Use chewing gum?
• Play musical instruments that involve mouth or jaw?
• Lean with hand on jaw or chin?
• Chew food on one side only?
• Eat between meals (food requiring lots of chewing)?
• Talk at length?
• Sing?
• Yawn excessively?
• Hold telephone between head and shoulder?
(Ohrbach R, Markiewicz M, McCall WD Jr. 2004)

61. TREATMENT OF MASTICATORY MUSCLE
DISORDERS
• Although no specific therapies have been proved to be uniformly
effective, many of the conservative modalities have proved to be
at least as effective as most forms of invasive treatment in
providing symptomatic relief.
• Because such modalities do not produce irreversible changes, they
present much less risk of producing harm. Professional treatment
should be augmented with a home-care program whereby patients
are taught about their disorder and how to manage their
symptoms. (Greene CS. 2010, Glaros AG & Burton E. 2004)

63. • There is evidence to suggest that multimodal therapy and
combining treatments produces a better outcome. (Galdon MJ et
al 2006, Ebrahim S et al 2012)
• Avoidance therapy and cognitive awareness plays a vital role in
patient care but has little scientific evidence to support its use.
(Scrivani SJ et al 2008, Clark GT, Minakuchi H. 2006, Clark GT et
al 1989, Dworkin SF 2006)

64. • Four behaviors should be avoided in the patient with masticatory
muscle pain:
1. Avoidance of clenching by reproducing a rest position where the
patient’s lips are closed but teeth are slightly separated
2. Avoidance of poor head and neck posture
3. Avoidance of testing the jaw or jaw joint clicking
4. Avoidance of other habits such as nail biting, lip biting, gum
chewing, and so forth

67. • Many patients report benefit from heat or ice packs applied to
painful MOM. The local application of heat can increase circulation
and relax muscles, whereas ice may serve as an anesthetic for
painful muscles.
• In addition, stretch therapy must be part of a self-care program.
Stretches should be done multiple times daily to maximize
effectiveness. The most effective stretching exercise is passive
stretching.

68. Passive stretching
• Certain exercises can help you relieve the pain
that comes from tired, cramped muscles. They
can also help if you have difficulty opening your
mouth. The exercises described work by helping
you relax tense muscles and are referred to as
“passive stretching.” The more often you do
these exercises, the more you’ll relax the
muscles that are painfully tense. Do these
exercises 2 times daily:
1. Ice down both sides of the face for 5 to 10
minutes before beginning (ice cubes in
sandwich bags or packs of frozen vegetables
work well for this).

69. 2. Place thumb of one hand on the edge of the upper front teeth
and the index and middle fingers of the other hand on the edge
of the lower front teeth, with the thumb under the chin.
3. The starting position for the stretches is with the thumb of the
one hand and index finger of the other hand just touching.
4. Gently pull open the lower jaw, using the hand only, until you
feel a passive stretch, not pain, hold for 10 seconds, then allow
the lower jaw to close until the thumb and index finger are once
again contacting; it is crucial that when doing these exercises
not to use the jaw muscles to open and close, but rather manual
manipulation only (the fingers do all the work!).

70. 5. Repeat the above stretching action 10 times, performing 2 to 3
sets per day, 1 in the morning and 1 or 2 in the evening.
6. When finished with the exercises, one can place moist heat to
both sides of the face for 5 to 10 minutes (heating a wet
washcloth in the microwave for about 1 minute works well for
this).

71. Physiotherapy
• Physiotherapy helps to relieve musculoskeletal pain and restore normal
function by altering sensory input; reducing inflammation; decreasing,
coordinating, and strengthening muscle activity; and promoting the
rehabilitation of tissues.
• Despite the absence of well-controlled clinical trials, physiotherapy is a
well-recognized effective and conservative therapy for many disorders of
the MOM.
• Physical Therapy Techniques
• Posture training
• Exercises
• Mobilization

72. • Physical Agents and Modalities
• Electrotherapy and transcutaneous electrical nerve stimulations (TENS)
• Ultrasound
• Iontophoresis
• Vapocoolant spray
• Trigger-point injections with local anesthetic or Botox
• Acupuncture
• Laser treatment

73. SPLINT THERAPY
• Splints, orthotics, orthopedic appliances, bite guards, nightguards, or
bruxing guards are used in TMD treatment, and often for disorders of
masticatory muscles. (Scrivani SJ et al 2008)
• Several studies on splint therapy have demonstrated a treatment effect,
although researchers disagree as to the reason for the effect. (Galdon
MJ et al 2006, de Leeuw R 2008, Lobbezo F et al 2004)
• In a review of the literature on splint therapy, Clark and colleagues
(Clark GT et al 2006, Clark GT et al 1989) found that patients reported a
70% to 90% improvement with splint therapy.
• A review of the research on splint therapy suggests that using a splint as
part of therapy for masticatory myalgia, arthralgia, or both may be
supported by the literature in case-control studies.(Kreiner M et al 2001)

74. • Conversely, there is insufficient evidence on review of published
randomized controlled trials to support the use of stabilization splint
therapy over other active interventions in the treatment of myofascial
pain. Splints appear to be better than no treatment, but only as
effective as other active interventions for myofascial pain. (Kreiner M et
al 2001, Fricton J et al 2010, Truelove E et al 2006, Michelotti A 2012)
• A systematic review and meta-analysis by Ebrahim and colleagues
(Ebrahim S et al 2012) reviewed 11 eligible studies of 1567 patients, and
demonstrated promising results for pain reduction, very low evidence for
an effect on quality of life, and significant research bias.

75. PHARMACOLOGIC THERAPY
• Both clinical and controlled experimental studies suggest that medications may
promote patient comfort and rehabilitation when used as part of comprehensive
treatment.
• Although there is a tendency for clinicians to rely on “favorite” agents, no single
medication has proved to be effective for the entire spectrum of TMDs. (Scrivani
SJ, et al 2008, Benoliel R et al. 2011, Benoliel R & Sharav Y 2010, Clark GT et al
2006, Clark GT et al 1989)
• With respect to pain associated with disorders of the MOM, analgesics, nonsteroidal
anti-inflammatory agents, corticosteroids, benzodiazepines, muscle relaxants, and
low-dose antidepressants have shown efficacy.
• Many of the medications used for fibromyalgia can be used for patients with
masticatory muscle disorders. (Clauw DJ. 2009)
• These agents are versatile and effective at treating the multiple symptoms
associated with chronic muscle pain.

77. Studies
• Marcelo Palinkas et al in 2019 demonstrated that the loss of
periodontal supporting structures associated with dental mobility
showed a significant impact on masticatory cycle efficiency in
chewing foods. Individuals with periodontitis showed the lower
bite force values. In clinical planning, the findings suggested that
dental mobility should be considered when determining clinical
treatments aimed at improving masticatory efficiency and bite
force in individuals with the periodontal disease.

78. • Zekeriya Taşdemir in 2019 studied Masseter muscle thickness
and elasticity in periodontitis and concluded that the gingivitis
group had significantly thicker masseter during both contraction
and rest. On the other hand, when the elasticity of the masseter
was evaluated, there were no significant differences found
between the two groups and two sides for each group. Masseter
muscle thickness in the periodontitis group was found to be
decreased compared with that in the gingivitis group.
Furthermore, loss of periodontal tissues due to periodontitis
reduces the masticatory ability.

79. • Kemal S. Turker et al in 2006 reviewed the role of periodontal
mechanoreceptors in mastication and said that periodontal
mechanoreceptors (PMRs) supply information regarding static jaw
positions; forces applied to the teeth and contribute to the
development of strong and effective masticatory forces. They also
respond to jaw movement and chewing forces dynamically, to
protect the teeth and supporting tissues. PMRs contribute not only
to the protection of the teeth and the oral structures, but also
contribute to the ability of the system to hold morsels between
teeth.

80. • Judith L.Gartner et al in 2000 studied the effect of
osseointegrated implants on the coordination of masticatory
muscles and concluded that patients with implant-supported
prostheses appeared to be well adapted to perform habitual
masticatory functions. However, during a nonhabitual function
such as maximal occluding force, the study revealed a less
coordinated masticatory muscle activity in the implant patients.

81. • Gilbert AD & Newton JP in 1997 studied the effect of chronic
periodontal disease on human jaw muscles using computed tomography.
Results from the 'diseased' group (subjects suffered from chronic
periodontal disease) as compared with the 'control' group (subjects had
no history of periodontal disease) revealed that in the former the cross-
sectional area (CSA) of masseter and medial pterygoid was reduced
significantly by 25% and 10%, respectively. There were no significant
differences in the X-ray density of both muscles between the two
groups, which indicated a similar fibro-fatty content. These findings
indicate a reduction in the masticatory force that may be utilized by
patients with reduced periodontal support and may help explain their
masticatory difficulties.

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