Mastication And Occlusion Flashcards
(195 cards)
1
Q
What is mechanoreception?
A
Detection of mechanical stimuli
2
Q
What tooth tissue contains lost of mechanoreceptors?
A
The PDL
3
Q
Define, exteroception.
A
Give information about things coming into contact with the body
4
Q
Define, proprioception.
A
Awareness of position of body parts in relation to each other and surroundings
5
Q
What four structures are oro-facial mechanoreceptors found in?
A
- mucosa
- PDL
- muscles
- joint receptors (TMJ)
6
Q
In what two ways are mechanoreceptors physiologically classed?
A
- Adaptation properties
- Receptive field size
7
Q
What is a ‘receptive field’?
A
The area/space where a stimulus will affect the receptor
8
Q
What is the key difference between rapidly adapting and slowly adapting mechanoreceptors?
A
Slowly adapting continue responding to a stimulus, whereas rapidly adapting receptors respond only at the onset of stimulation.
9
Q
what class of mechanoreceptor has rapid adaptation and a small receptive field?
A
RA I
10
Q
what class of mechanoreceptor has rapid adaptation and a large receptive field?
A
RA II
11
Q
what class of mechanoreceptor has slow adaptation and a large receptive field?
A
SA II
12
Q
what class of mechanoreceptor has slow adaptation and a small receptive field?
A
SA I
13
Q
Which receptor field has lots of receptors in a specific area and is therefore more detailed? Small or large?
A
Small receptor field
14
Q
What are the four separate types of mechanoreceptors?
A
- Meissner’s Corpuscle
- Pacinian Corpuscle
- Merkel Cells
- Ruffini Ending
15
Q
What are the two types of rapidly adapting mechanoreceptors?
A
- Meissner’s Corpuscle
- Pacinian Corpuscle
16
Q
What are the two types of slowly adapting mechanoreceptors?
A
- Merkel Cells
- Ruffini Ending
17
Q
Which type of mechanoreceptor is rapidly adapting and has a small receptive field, and is therefore referred to as an RA I mechanoreceptor?
A
Meissner’s Corpuscle
18
Q
Which type of mechanoreceptor is slowly adapting and has a small receptive field, and is therefore referred to as an SA I mechanoreceptor?
A
Merkel Cells
19
Q
Which type of mechanoreceptor is rapidly adapting and has a large receptive field, and is therefore referred to as an RA II mechanoreceptor?
A
Pacinian Corpuscle
20
Q
Which type of mechanoreceptor is slowly adapting and has a large receptive field, and is therefore referred to as an SA II mechanoreceptor?
A
Ruffini Ending
21
Q
What are the type of mechanoreceptive nerve endings found in PDL?
A
Ruffini endings
22
Q
What type of nerve axon makes up PDLM’s?
A
A-beta axons
23
Q
What does PDLM’s stand for?
A
Periodontal Ligament Mechanoreceptors
24
Q
What main property of PDLM’s allows for easy localisation of pain?
A
They have no branched axons between adjacent teeth
25
Why are the nerves at the apex of a tooth activated the most?
Because this is where most tension within the PDL is
26
What direction of applied force on a tooth will cause most tension and action potential firing in a slowly adapting manner?
Mesially
27
Within the PDL, where are slowly adapting, low threshold mechanoreceptors found?
Apically
28
Within the PDL, where are rapidly adapting, high threshold mechanoreceptors found?
Cervically
29
how many microns of tooth movement is enough to activate PDL mechanoreceptors?
10 microns
30
What function do PDLM’s control?
Fine motor control
31
Where in the CNS do mechanoreceptors initially synapse?
Trigeminal nucleus
32
what are the three receptors involved in proprioception and where are they found?
1. Muscle spindles (within body of muscle)
2. Golgi tendon organs (within tendons)
3. Joint receptors (within joint)
33
What movement of the jaw are muscle spindles involved with? Closing of jaw, opening of jaw, or both?
Closing of jaw
34
what are the two different types of fibres found in muscle?
1. Extrafusal
2. Intrafusal
35
What muscle fibre is described here:
Specialised muscle spindles within a capsule
Intrafusal muscle fibres
36
What muscle fibre is described here:
Bulk of the muscle fibres and is contractile
Extrafusal fibres
37
What part of the Intrafusal fibres is able to be stretched to activate nerve afferents?
Non-contractile central portion
38
What nerve endings within the Intrafusal fibre only detect the length of fibres?
Secondary (flower-spray) nerve endings
39
What nerve endings within the Intrafusal fibre detect the length of fibres and speed of change of length?
Primary annuli-spiral nerve endings
40
What type of motor neurone is an efferent nerve fibre, innervating Intrafusal fibres?
Gamma motor neurone
41
What motor neurones supply extrafusal fibres?
Alpha motor neurones
42
What happens to spindle activity if a muscle becomes more stretched?
It increases
43
What is the role of muscle spindles?
They give information about and maintain muscle length, as well as providing load compensation
44
Where are muscle spindle cell bodies found?
In the trigeminal mesencephalic nucleus
45
What motor neurones cause contraction of intrafusal fibres?
Gamma motor neurones
46
What does alpha-gamma coactivation ensure?
That the muscle spindles maintain sensitivity to stretch over a wide range of muscle lengths
47
What is the innervation and action of the masseter muscle?
Innervation: masseteric nerve (Vc)
Action: jaw close, assist protrusion and lateral movement
48
What are the main muscles of mastication with the skull?
Masseter
Temporalis
Medial pterygoid
Lateral pterygoid
49
What are the three main muscles of mastication that attach to the hyoid muscle?
Geniohyoid
Mylohyoid
Anterior belly of digastric
50
What is the Innervation and action of the temporalis muscle?
Innervation: deep temporal nerve (Vc)
Action: jaw close, retrude and assist lateral movement
51
What is the Innervation and action of the medial pterygoid muscle?
Innervation: nerve to medial pterygoid (Vc)
Action: jaw close, assist protrusion, and lateral excursion
52
What is the Innervation and action of the lateral pterygoid muscle?
Innervation: nerve to lateral pterygoid (Vc)
Action: protrude, assist wide open , and lateral excursion
53
What is the Innervation of the geniohyoid muscle?
C1
54
What is the Innervation of the mylohyoid muscle?
Nerve to mylohyoid (Vc)
55
What is the Innervation of anterior belly of digastric muscle?
Nerve to mylohyoid (Vc)
56
What type of joint is the TMJ?
Synovial joint
57
what are the two movements the TMJ is capable of?
Hinge and slide movements
58
What bone is the glenoid fossa within?
Temporal bone
59
What are the two layers that make up the joint capsule of the TMJ?
1. Outer fibrous layer
2. Inner synovial membrane
60
what layer of the joint capsule within the TMJ, secretes synovial fluid to fill the joint spaces?
Inner synovial membrane
61
what are the three accessory ligaments of the TMJ?
1. Stylomandibular ligament
2. Sphenomandibular ligament
3. Pterygomandibular ligament
62
What are the three main zones of the articular disc of the TMJ?
1. Anterior band
2. Intermediate zone
3. Posterior band
63
what nerves innervate the TMJ?
Vc: auriculotemporal, masseteric and deep temporal
64
What arteries supply the TMJ?
Superficial temporal artery and maxillary artery
65
What is intercuspal position?
The position of the jaws when the maxillary and mandibular teeth are in maximum intercuspation
66
In what clinical situation would you commonly assess a patient’s inter-cuspal position (ICP)?
To check bite after placing a restoration to ensure that the bite is not too high
67
What are the three complications that can arise if ICP is too high after placing a restoration, and not fixed?
- can be painful for patient as they will overload the tooth when they bite down
- The restoration may fracture
- will change the bite, so surrounding teeth may move out of position
68
At what point in daily life are teeth most likely in ICP?
While eating
69
Define occlusion
The contact relationships of teeth or equivalent
70
What is, the dynamic relationships of teeth when in sliding contact, referred to as?
Articulation
71
What are the three vertical jaw relationships?
1. Rest/postural position
2. Intercuspal position (ICP)
3. Retruded contact position (RCP)
72
What are the three vertical jaw dimensions?
1. Occlusal vertical dimension (OVD)
2. Rest vertical dimension (RVD)
3. Freeway space (FWS)
73
At rest/postural position, what position are the teeth in?
Teeth are apart
74
What is rest/postural position governed by?
Muscle elasticity
75
what does RCP stand for?
Retruded contact position
76
What is Retruded contact position also known as?
Ligamentous position
77
what vertical jaw relationship gives a reproducible relationship between the maxilla and the mandible?
Retruded contact position (RCP)
78
Describe the retruded contact position
Condyles retruded in glenoid fossa and teeth are in contact
79
Which muscle is going to pull mandible back into RCP?
The temporalis muscle
80
Clinically, what would you tell a patient to do in order to bring their occlusion into RCP?
Ask patient to curl tongue back to the roof of their mouth towards the soft palate and then close their mouth, this should allow for RCP.
81
What is occlusal vertical dimension (OVD) in regards to jaw relationships?
The face height with the teeth in ICP
82
What piece of equipment can be used to measure OVD of jaw relationship?
Willis gauge
83
What is the freeway space (FWS)?
The space between teeth in rest position OR difference between RVD and OVD on a Willis gauge
84
What is the normal measurement of FWS?
2-5mm
85
If a patient is edentulous, using a Willis gauge, how would you decide what height to restore occlusion to?
You would measure RVD and then subtract FWS
86
What are the 5 border movements of the mandible?
1. ICP
2. RCP
3. Lower extent of retruded hinge arc
4. Maximum opening
5. Maximum protrusion
87
What is incisal guidance?
The influence on mandibular movements provided by contacting surfaces of the maxillary and mandibular anterior teeth
88
When moving the jaw laterally, what is the side called to which the teeth move?
The working side
89
When moving the jaw laterally, what is the side called to which the teeth move away from?
The non-working side
90
What is group function?
Lateral force spread to a number of teeth
91
Normally teeth do not contact on the non-working side, in what scenario will there be non-working side contact?
If the patient has a cross bite
92
What is more favourable, canine guidance or group function, and why?
Group function, as the load is spread over more teeth
93
What is the lateral bodily movement of the working side condyle called, where it rotates around vertical axis?
Bennett movement
94
Which muscle drives lateral excursion?
Lateral pterygoid
95
What does F/F dentures stand for?
Full upper/full lower dentures
96
What does P/P dentures stand for?
Partial upper/partial lower dentures
97
What does TMD stand for?
Temperomandibular Disorders
98
Define TMD’s?
A group of conditions affecting the temperomandibular joint and/or the muscles of mastication
99
What is the annual average incidence of TMD?
4%
100
what is the prevalence of TMD?
10-15%
101
When would pain due to TMD be expected to exacerbate?
Upon eating (particularly hard foods) and attempted wide mouth opening
102
What is clicking, snapping or popping of the the TMJ indicative of?
Anterior disc displacement
103
What is crepitus?
Grinding/crunching noise upon joint movement
104
What are three co-morbidities of TMD?
- fibromyalgia
- chronic pain
- psychological factors
105
How would you palpate the temporalis muscle when examining for TMD?
Palpate with patients teeth clenched, palpate above the ear and forwards above the eye
106
How would you palpate the masseter muscle when examining for TMD?
Bimanual palpation, where you place two fingers inside patients cheek and two fingers on outside of patients cheek
107
What is the measurement of opening of the jaw, that would be deemed as abnormal? And suggestive of TMD.
Less than 40mm including vertical incisal overlap
108
What signs on the intra-oral soft tissues are suggestive of a habit such as tooth clenching, grinding or tongue thrusting?
- ridging buccal mucosa at level of occlusal plane
- Scalloping of borders of tongue (wavy tongue edges)
109
What type of radiograph could be taken, if a patient has suspected degenerative changes in their TMJ?
CBCT
110
What type of radiograph can be taken if disc displacement of the TMJ is suspected?
MRI
111
What are the two main groups that TMD disorders are split into?
1. Pain related TMD’s
2. Intra-articular TMD’s
112
What are the two subtypes of pain related TMD’s?
- myalgia
- arthralgia
113
What is myalgia? And what is a chronic condition associated with it?
Disorders related to muscle pain and myofascial pain.
114
what is myofascial pain?
A chronic condition that causes pain in the musculoskeletal system
115
What is arthralgia? And what symptom would indicate this in regards to TMD?
Disorders related to joint pain, and a headache related to TMD.
116
What are the four categories of intra-articular TMD’s?
1. Disc displacement with reduction
2. Disc displacement with reduction with intermittent locking
3. Disc displacement without reduction with limited opening
4. Disc displacement without reduction without limited opening
117
Name two associated conditions of intra-articular TMD
1. Degenerative joint disease
2. TMJ subluxation
118
What is subluxation?
A condition where the condyle translates anteriorly of the articular eminence during jaw opening and briefly catches in an open position before returning to the fossa spontaneously
119
What is disc displacement with reduction characterised by?
Clicking jaw joint
120
What is disc displacement without reduction with limited opening characterised by?
A history of previous clicking which stops at the same time as onset of restricted mouth opening
121
What are the two provocation tests you could carry out to examine for myalgia?
1. Palpation of temporalis or masseter muscle
OR
2. Maximum unassisted to assisted opening movements
122
Provocation testing of what anatomical structure is required to examine a patient with suspected arthralgia?
Provocation testing of the TMJ
123
What intra-articular TMD involves no reduction of the anterior disc and persistent limited mandibular opening (closed lock)?
Disc displacement without reduction with limited opening
124
A degenerative disorder involving the joint characterised by deterioration of articular tissue with associated osseous changes in the condyle and/or articular eminence.
Degenerative joint disease
125
In degenerative joint disease, when arthralgia is present accompanying crepitus, what is the term used to describe this?
Osteoarthritis
126
Upon examination of the TMJ, what characterises degenerative joint disease?
Crepitus detected with palpation during either opening, closing, right or left lateral or protrusion movements
127
For subluxation to be termed as such, who is required to move TMJ joint back into position, the patient or the clinician?
The patient. It is termed luxation if assistance of the clinician is required
128
What is the common manipulative manoeuver required to return jaw from subluxation?
Patient moves jaw from side to side
129
What is the conservative management recommended to patients with chronic TMD conditions?
Regular application of gentle heat
130
What is the conservative management recommended to patients with acute onset pain and/or restricted mouth opening due to TMD?
Regular application of cold pack
131
If a patient presents with muscle spasm or disc displacement without reduction with limited opening, what medication would appropriate to prescribe for them, and for what length of time?
Diazepam 5 day course so long as not contra-indicated
132
When would you refer a patient with TMD?
1. Chronic symptoms lasting more than 3 months
2. Persistent or worsening symptoms despite treatment
3. An uncertain diagnosis
4. Marked psychological distress
5. Unexplained persistent pain
133
What model is useful for highlighting patients at risk of chronic TMD symptoms? And what does it stand for?
FLATS.
Fear of pain
Low mood
Avoidance of functional activities
Thinking the worst
Social impact
134
How many teeth do you require for sufficient masticatory function?
5-5 teeth (at least 20 teeth)
135
What movement of the TMJ occurs on normal jaw opening?
Hinge
136
What movement of the TMJ occurs on wide jaw opening?
Hinge and slide
137
What movement of the TMJ occurs on jaw protrusion?
Slide
138
In lateral excursion, what is the movement of the non-working side condyle?
It moves downwards, forwards over the articular eminence, and medially
139
what is the movement of the working side condyle?
Rotates around vertical axis, completing a lateral bodily movement known as Bennett movement
140
what is the average duration of a chewing cycle?
0.5-1.2 seconds
141
What are the four stages of a chewing cycle?
1. Opening
2. Fast closing
3. Slow closing
4. Intercuspal phases
142
In what stages of the chewing cycle does food breakdown occur?
Slow closing and intercuspal phase
143
What is the sequence of muscle activation for jaw opening in the chewing cycle?
1. Mylohyoid
2. Digastric
3. Lateral Pterygoid
144
What is the sequence of muscle activation for jaw closing in the chewing cycle?
1. Temporalis
2. Masseter
3. Medial pterygoid
145
What are the three levels of control of mastication?
1. Reflex
2. Pattern generator
3. Voluntary
146
What happens during pattern generator control of mastication?
Action potentials are fired to different muscles in a certain pattern to cause certain movements (activates muscle at the right time)
147
What is the pattern generator within the brain stem?
The chewing centre
148
What does the motor nucleus, in the brain stem supply?
Muscles
149
Where is the chewing centre situated in the brain stem?
Medial to trigeminal mesencephalic nucleus
150
What are two common examples of reflex?
1. Knee jerk reflex
2. Jaw jerk reflex
151
What does reflex latency mean?
The time that elapses between application of a stimulus and the start of a reflex response
152
Why is reflex latency shorter for jaw-jerk reflex compared to knee-jerk reflex?
Because the distance from the masseter to the brain is much shorter than the knee to the quadriceps femoris
153
Rest/postural position for jaws is not reproducible throughout life. True or false?
False, it’s remains reproducible throughout life in both dentate and edentulous subjects
154
What is the role of stretch reflexes during running?
They stabilise the jaw during vigorous head movements
155
What are the roles of inhibitory jaw reflexes?
1. Prevent overloading of the masticatory system
2. To facilitate opening
156
Closing teeth together causes an inhibitory jaw reflex. True or false?
True
157
What measurement of tooth movement in microns is enough to produce inhibitory reflex effects in the masseter muscle?
Around 9 microns
158
What is the jaw unloading reflex?
The reflex inhibition of the muscles of mastication which occurs when food or other material between the jaws suddenly breaks or collapses and which helps stop the jaws forcefully coming together
159
Why would you choose to supply a patient with a soft splint?
If they grind their teeth at night
160
What are three types of splints to manage craniomandibular disorders (CMD)?
- soft splints
- full coverage hard splints
- repositioning splints
161
What type of splint is described:
Hard splint which aims to give an ideal occlusion by retruding the jaw so that RCP is the same as ICP
Stabilisation splint
162
What type of stabilisation splint is for the maxillary arch?
Michigan splint
163
what is the advantage of a Michigan splint over a soft splint?
A Michigan splint is harder and therefore less likely to be worn down by bruxism
164
What is the complication of stabilisation splints?
Hard to make
165
what stabilisation splint is for the mandibular arch?
Tanner appliance
166
What is a thermoformed splint?
A stabilisation splint that is soft on the inside and hard on the outside, this is usually comfortable to wear for patient.
167
What would you make an anterior repositioning splint for?
For patients who suffer with disc displacement with reduction, often used to reduce pain.
168
What dental arch does the anterior repositioning splint fit onto?
Mandibular arch
169
Why should you be very hesitant to place an anterior repositioning splint on a young person (16-17)?
Because the condyle is most likely not sitting high in the glenoid fossa, it will grow and the mandible may remain protruded even without the splint
170
What type of splint should never be used due to risk of over-eruption?
Partial coverage splints
171
What are the five types of articulators?
1. Hand held
2. Simple hinge
3. Plane line
4. Average value
5. Semi-adjustable-denar
172
What are simple hand held casts used for?
Orthodontic analysis and to analyse occlusion in ICP
173
Which type of articulator could be used for a simple denture to assess only ICP?
Plane line articulator
174
Which type of articulator is used for simple fixed prosthesis for teeth not involved in guidance and also removable prostheses?
Average value articulator
175
What are the two types of semi-adjustable articulators?
- Dentatus articulator called a non-arcon articulator
- Denar Mark II Articulator called an arcon articulator
176
What is the difference between a non-arcon and an arcon articulator?
Non-arcon condyle is part of maxillary component, whereas arcon condyle is part of mandibular component
177
What is a face bow and what is it used for?
A dental instrument used in the field of prosthodontics. It’s purpose is to transfer functional and aesthetic components from patients mouth to the dental articulator. Specifically it transfers the relationship of maxillary arch and temperomandibular joint to the casts.
178
Which articulators are face bows used in conjunction with?
Average value and Semi adjustable articulators
179
Is an average value articulator non-arcon or arcon?
Non-arcon
180
What articulator would you use for restoration of teeth that are involved in guidance, advanced restorative work- e.g. bridges, implants and occlusal reorganisation?
Semi-adjustable articular, specifically an arcon articulator.
181
What is a class 1 incisor relationship?
The lower incisor edges occlude with the upper central incisor central plateaus
182
What is a class 2 division 1 incisor relationship?
- The lower central incisor edges sit POSTERIORLY relative to the upper central incisor central plateaus.
- The upper central incisors are either PROCLINED or of an enlarged incilination
- Often an increased overjet
183
What is a class 2 division 2 incisor relationship?
- The lower central incisor edges sit POSTERIORLY relative to the upper central incisor central plateaus.
- The upper central incisors are RETROCLINED
- Often a minimal overjet
184
What is a class 3 incisor relationship?
- The lower central incisor edges sit ANTERIORLY relative to the upper central incisor central plateaus.
- the overjet is reduced or reversed
185
what are molar relationships also referred to as?
Angle’s classification
186
What is a class 1 molar relationship?
Mesiobuccal cusp of maxillary molar sits in buccal groove of mandibular molar
187
What is a class 2 molar relationship?
Disto buccal cusp of maxillary molar sits in buccal groove of mandibular molar
188
What position is the mandible in a class 2 molar relationship?
Backwards
189
What is a class 3 molar relationship?
Mandibular molar is anterior to the maxillary molar (sits a whole unit forward)
190
what position will the mandible be in a class 3 molar relationship?
Forwards
191
what is meant by ‘skeletal base’?
The relationship between the mandible and maxilla
192
according to the BULL rule, what cusps should not be in contact in the maxillary arch?
Buccal cusps of teeth
193
In the mandibular arch, which cusps should not be in contact with other teeth?
Lingual cusps
194
In an ideal occlusion, which teeth are the only ones in the mouth to contact both an anterior and posterior tooth?
Maxillary canines
195
Which teeth are the only ones to not occlude with two other teeth in the mouth?
Mandibular central incisor and maxillary third molars
