Local Anaesthetic Flashcards
(186 cards)
1
Q
What does a white handle on a syringe indicate?
A
It is single-use
2
Q
What type of aspiration does an ultra safety plus twist syringe have?
A
Self-aspiration
3
Q
Which direction should the finger grip be twisted when it is inserted into syringe barrel to lock it into place?
A
Clockwise
4
Q
What is the purpose of the small protuberance at the bottom of the cartridge barrel?
A
It depresses the cartridge diaphragm throughout the injection procedure
5
Q
In what instance would you slide the protective sheath down the barrel of syringe until you hear first click?
A
If you need to set the needle down or change cartridge
6
Q
When you hear first click of protective sheath down barrel of syringe what does this mean?
A
It is in holding position
7
Q
When you are finished with injection what should you immediately do?
A
Push protective sheath further until you hear a second click, this is in final position and is fully locked.
8
Q
What direction should the finger holder of syringe be turned to be released from barrel?
A
Anti-clockwise
9
Q
What are the three main components of dental local anaesthetic equipment (syringe)?
A
- Syringe barrel with needle
- LA cartridge
- Plunger/handle
10
Q
What component of the syringe can be either single-use or come in a form that may be sterilised and reused?
A
Plunger/handle
11
Q
What is the bevel?
A
The tip of the needle which is very sharp and appears asymmetric
12
Q
What are the 3 types of needle/syringe used in dental LA?
A
- Ultrashort
- Short
- Long
13
Q
What is the length and gauge of an ultrashort needle?
A
Length: 10mm
Gauge: 30
14
Q
Define gauge in relation to LA
A
The size of the hole in needle
15
Q
If the gauge becomes higher, what would happen to the size of hole in the needle?
A
It would decrease
16
Q
How many types of ‘short’ needle can you have and what is the difference between them?
A
Two types. The length is the same, however the gauge differs
17
Q
What are the two different gauges of small needle?
A
Blue = 30
Orange = 27
18
Q
What is the length of a small needle?
A
25mm
19
Q
What is the length and gauge of a long needle?
A
Length: 35mm
Gauge: 27
20
Q
What LA is generally used in Dundee dental hospital? (Trade name)
A
Lignospan special
21
Q
What volume of solution does one cartridge of lignospan specail contain?
A
2.2ml
22
Q
What does the 2.2ml solution found in one cartridge of lignospan special contain?
A
44 mg lidocaine hydrochloride
27.5 micro grams adrenaline
23
Q
What does adrenaline act as?
A
A vasoconstrictor
24
Q
Apart from LA and vasoconstrictor, what else is contained within one cartridge of lignospan special?
A
- stabiliser/ preservative
- isotonic carrier medium
25
On disposal, what components of a syringe would be put into the sharps bin?
Cartridge
Barrel and needle
26
What component of a syringe would be disposed of in the clinical waste bin?
Fingergrip/ handle
27
What aids the prevention of intra-vascular injection?
Aspiration
28
What could be the two main consequences of intra vascular injection?
- inadequate/failure of anaesthesia
- increased risk of systemic side effects
29
Lowering pressure on the cartridge achieves what?
Aspiration ( if in vessel, blood will flow back)
30
Define anaesthesia
Loss of sensation
31
Define analgesia
Loss of pain sensation
32
Loss of sensation in a localised area of the body, involving no loss of consciousness is a result of?
Local anaesthetic
33
What was found to increase the duration of anaesthesia in 1901?
Adrenaline
34
What can induce haemostasis?
Adrenaline
35
Define haemostasis
Cessation of bleeding
36
LA is used for pain control in what scenarios?
- during procedures
- post-operatively
37
Give some examples of dental procedures where LA may be used
Scaling, extraction, endodontics
38
What are the four different types of LA techniques ?
1. Topical
2. Infiltration
3. Regional (block)
4. Supplementary techniques
39
Anaesthesia of surface tissues is achieved by application of what?
Topical anaesthesia
40
Anaesthesia of the root apex of a tooth is achieved through what technique?
Infiltration
41
Anaesthesia of a nerve trunk is achieved through what technique?
Regional (block)
42
What type of anaesthetic is used in very minor oral surgery, abscess incisions, or on the palate for impressions?
Topical anaesthesia
43
What determines the effectiveness of infiltration anaesthesia?
The permeability of bone, through which the solution must pass
44
If there is dense bone, will this result in less or more effective anaesthesia?
Less effective
45
If there is thin and porous bone, will this result in less or more effective anaesthesia ?
More effective
46
what length of needle is typically used for infiltrations?
25mm (short needle)
47
What is key to remember about speed when injection?
Always inject SLOWLY
48
What tooth causes the most complications for infiltration anaesthesia?
Maxillary 6’s
49
Why do maxillary 6’s cause such a complication for infiltration procedures?
- thick bone at zygomatic process, where upper 6 lays.
- divergent palatal root on upper 6 is difficult to reach
50
What type of anaesthesia will not work on very dense outer cortical bone ( i.e. surrounding lower molars)?
Lidocaine infiltration
51
Infiltration with another LA is believed to work on very dense outer cortical bone. What is this anaesthetic?
Articaine
52
Intraligamentary and intraosseous are two forms of what?
Supplementary technique
53
How would you perform an intraligamentary supplemental technique?
Inject down PDL
54
Is an intraligamentary technique high or low pressure?
High
55
How would you perform an intraosseous supplementary technique?
Drill hole into bone, inject through hole in bone.
56
Where is articaine metabolised?
In the plasma and liver
57
How are LA’s classified by structure?
They are amide or ester
58
Give examples of amide LA’s
- lidocaine, prilocaine, articaine etc.
59
Give an example of an ester LA
Benzocaine
60
What LA is mostly amide in structure but also has ester links?
Articiane
61
What is the impact of an LA with a low pKa?
PKa reflects solubility. An anaesthetic can exist on either a charged or uncharged form, the more uncharged, the easier it will pass through lipid membrane. The lower the pKa ( more uncharged) , the faster the onset of anaesthetic.
62
How does pH impact LA performance?
Low pH gives more charge which has a negative/lowered effect on LA performance
63
Name an LA with a high protein binding
Articaine
64
Name the least vasodilatory LA
Mepivocaine
65
Where are most LA’s metabolised?
Liver and plasma
66
What LA is metabolised in the lungs?
Prilocaine
67
What is the effect of LA drugs on the heart?
They act as vasodilators, therefore calm down an overexcitable heart
68
Why is a vasoconstrictor commonly used alongside LA agent?
Prolongs length of anaesthesia
69
What is the most potent vasoconstrictor used in dentistry?
Adrenaline
70
Name two vasoconstrictors that can be used alongside LA agent
Adrenaline
Phelypressin
71
Which component of the LA cartridge requires a preservative/ stabiliser? And why?
Adrenaline
As it oxidises quickly
72
What is the affect of a vasoconstrictor in systemic uptake of anaesthetic?
Slows it down
73
What is the max dose of lidocaine + adrenaline that can be given to an 85KG healthy adult male?
300mg ( 6.8 cartridges)
74
What LA preparation could be given to a patient who cannot accept adrenaline?
Mepivocaine and prilocaine
75
Why does articaine have a low systemic toxicity?
It is broken down in plasma and liver so does not remain in high levels in the blood
76
What determines the efficacy of an infiltration LA?
Bone density
77
State the boundaries of the pterygomandibular space
Lateral= mandible
Medial= medial pterygoid
Anterior = buccinator
Posterior = parotid gland
Superior= lateral pterygoid
78
What nerves need to be anaesthetised to extract a lower molar tooth?
- inferior alveolar nerve
- long buccal nerve
- lingual nerve
79
What tissues are supplied by the incisive nerve?
Anterior teeth (incisors and canines)
80
What LA technique is used predominantly for maxillary anaesthesia?
Infiltrations
81
What are the four important nerves that branch for CN V2 regarding delivery of maxillary LA?
- posterior superior alveolar nerve
- middle superior alveolar nerve
- anterior superior alveolar nerve
- infraorbital nerve
82
Where does anaesthesia of the anterior superior alveolar nerve block sensation to?
The maxillary incisors and canine (bilaterally)
83
Where does anaesthesia of the middle superior alveolar nerve block sensation to?
The maxillary pre-molars and mesio-buccal root of 1st molar (bilaterally)
84
Where does anaesthesia of the posterior superior alveolar nerve block sensation to?
Maxillary molars (bilaterally)
85
Where does anaesthesia of the incisive branch of the nasopalatine nerve block sensation to?
The palatal gingivae of anterior teeth and the anterior part of palate ( from insicors to canines)
86
What part of the gingiva does the infraorbital nerve innervate?
High up in the labial sulcus
87
To achieve anaesthesia of the 2nd upper premolar through buccal infiltration, what nerve ending would you aim to block?
Middle superior alveolar nerve
88
What are the two main LA techniques used for maxillary anaesthesia?
Infiltrations and regional blocks
89
This LA technique is easy, safe, has low risk of intra vascular administration and low risk of nerve injury. What is being described?
Infiltration technique
90
What is the main downfall of infiltration technique?
It requires local diffusion for effectiveness, this can be tricky to achieve at times.
91
This LA technique can be difficult and has a higher risk of intra vascular administration and nerve injury than another commonly used technique.
Regional block
92
What does infiltration anaesthesia set out to achieve?
Diffusion of LA solution close to, to in the target tissue ( root apex)
93
What type of needle would you use for an infiltration?
25mm (blue-cap short needle)
94
What type of bone does infiltration work best with?
Thin porous bone ( e.g. maxillary anterior teeth)
95
In what area of the dentition can infiltrations prove difficult to achieve?
Around the maxillary first molar. This is due to its palatal divergent root as well as the thicker lateral bone due to the zygomatic process.
96
What type of bone will lidocaine infiltrations not work on?
Very dense outer cortical bone
97
What LA solution would work on infiltration of dense outer cortical bone? And why?
Articaine as it has higher diffusivity rate than lidocaine
98
What LA solution is most commonly used for infiltrations?
Lidocaine
99
How would you apply topical anaesthesia?
1. Identify injection site
2. Dry with 3 in 1
3. Apply gel using cotton wool or gauze
4. Leave cotton wool/gauze in place for 3-5 mins
5. Deliver injection or perform procedure
100
When giving an infiltration, what must the tissue be?
Taught
101
What angle must the syringe be to the bone when giving infiltration?
45 degrees
102
At what point would you inject solution when giving an infiltration?
When bone has been contacted and aspiration has occurred
103
At what speed should you inject LA solution?
Slowly
104
What is aspiration?
Technique used to reduce the risk of intra vascular injection
105
What would indicate that an injection has gone into a vessel?
If blood appears in the cartridge after aspiration
106
How long should it take to administer 1ml of LA solution ( half a cartridge)?
1 minute
107
Why are palatal infiltrations often uncomfortable/painful?
Because the periosteum is lifted from the bone during injection
108
In what situation would you most likely require palatal infiltrations?
For tooth extractions
109
What maxillary nerves are commonly anaesthetised using regional block technique?
Greater palatine nerve or the incisive nerve
110
What needle would be used for maxillary regional blocks?
25mm ( blue-cap short needle)
111
How would you locate the incisive branch of the nasopalatine nerve for a regional block?
Would be found in line with canines (horizontally) and in line with the interproximal space between central incisors ( vertically)
112
What location would you find the greater palatine nerve when giving a regional block?
In line with the interproximal space between the upper 2nd and 3rd molars
113
Which LA technique would be required if an upper canine required a restoration?
Labial infiltration for pulpal anaesthesia
114
Which LA technique would be required for extraction if upper canine?
Labial and palatal infiltration
115
Which LA technique would be required to restore an upper 7?
Buccal infiltration
116
Which LA technique would be required for the extraction of an upper 7?
Buccal and palatal infiltration
117
Which LA technique would be required to restore all upper premolars and molars?
A range of buccal infiltrations
(possibly a palatal infiltration for upper 6 divergent root)
118
Which LA technique would be required for extraction of upper all premolars and molars?
A greater palatine nerve block
119
Which LA technique would be required to restore both upper central incisors?
Two labial infiltrations
120
Which LA technique would be required for extraction of both upper central incisors?
Labial infiltration and a nasopalatine nerve block
121
What are the main nerves associated with the CN V3 for mandibular anaesthesia?
- inferior alveolar nerve
- lingual nerve
- long buccal nerve
- mental nerve
- incisive nerve
122
The lingual nerve enters the mandible. True or false?
False. It does not enter the mandible.
123
What area of the mouth does the mental nerve innervate?
The lower lip and surrounding soft tissues
124
What teeth does the inferior alveolar nerve innervate?
All molars and premolars of the mandible
125
What teeth does the incisive nerve innervate?
All incisors and canines of the mandible
126
What type of nerve block can anaesthetise a while side of the mandible?
Inferior alveolar nerve block
127
What needle is required for an inferior alveolar nerve block?
35mm long needle ( yellow-cap)
128
What is the common technique used for inferior alveolar nerve block?
The direct technique (halstead approach)
129
Where does the inferior alveolar nerve enter the mandible?
Through the mandibular foramen
130
What structure sits medial to the buccinator muscle and is of importance when it comes to IANB injections?
Pterygomandibular raphe
131
Which part of the inferior alveolar nerve is targeted when giving a block?
The part of the nerve that is exposed before it enters the mandible
132
What could happen if anaesthetic is deposited too far posteriorly during an IAN block?
It could penetrate the facial nerve causing drooping of the muscles of facial expression
133
What is the sign of mental nerve anaesthesia?
When the lower lip becomes numb
134
What is the medial border of the pterygomandibular space?
Medial pterygoid muscle
135
What is the lateral border of the pterygomandibular space?
Ramus of the mandible
136
What is the posterior border of the pterygomandibular space?
Parotid gland and facial nerve (CN VII)
137
What is the anterior border of the pterygomanibular space?
Buccinator
138
What is the superior border of the pterygomanibular space?
Lateral pterygoid muscle
139
What LA solution cannot be used for block anaesthesia in the mandible? And why?
Articiane, as it can have a negative impact on nerve trunks
140
When giving an IAN block, where would you place your supporting thumb?
In the coronoid notch of the anterior border of the ramus
141
What are the three boundaries of the injection point for an IAN block?
1. Thumb in coronoid notch
2.Pterygomandibular raphe
3. Vertical height halfway up thumbnail
142
When should you stop inserting the needle in an IANB?
When you hit bone ( approx 2.5cm)
143
What should the injection Angela of the syringe be for an IAN block?
The syringe should come across the mouth, the barrel should be sat over the premolars of the opposite side of the mouth
144
When would you known an IAN block was successful?
When the patients lower lip has gone numb
145
What is the difference between a lingual nerve block and IAN block?
Lingual nerve block is much more (1-1.5cm) superficial
146
Where does the long buccal nerve branch across and why is this important to know?
Branches across the coronoid notch, important for long buccal nerve block
147
Where would you administer a mental nerve block and with what needle?
Administer inferior to the interproximal space between premolars. Use a short needle (25cm)
148
In what scenario would you split the dose of LA between a labial and lingual infiltration?
For restoration or extraction of a mandibular incisor
149
In the mandible, what LA solution is preferred for infiltrations?
Articaine
150
Why should you never do a bilateral IAN block?
The patients mouth would be completely numb
151
What are the three types of supplemental technique?
- intra-osseous ( direct + intraligamentary + periodontal)
- intra- papillary
- Akinosi injection
152
Technique where needle is inserted into hole in the cortical bone
Direct intraosseous technique
153
What is the high pressure technique which administers low volumes of LA down the PDL?
Intraligamentary
154
What is the likely mode of action of the intraligamentary technique?
Spread of LA solution out of PDL to cancellous bone
155
What are the two main advantages of intra-papillary supplementary technique?
- allows for comfortable palatal anaesthesia
- useful for child treatment
156
What should you observe at the papilla while giving intra-papillary LA?
Blanching ( turns white)
157
What supplementary technique does not involve injection, but involves squirting topical LA into periodontal pocket?
Intra-periodontal pocket technique
158
What LA preparations cam be given plain? ( without vasoconstrictor)
- Mepivacaine
- prilocaine
159
What determines whether an anaesthetic is amide or ester?
The structure of it’s intermediate chain
160
What are examples of ester anaesthetics?
- procaine
-benzocaine
161
What are examples of amide anaesthetics?
- lidocaine
- prilocaine
- mepivacaine
- bupivacaine
- articaine
162
Which LA preparation is classed as an amide but also has an ester link?
Articiane
163
All LA used by injection are what? Amides or esters.
Amides
164
What is the specific receptor theory for how anaesthetic travels through membrane to access Na+ channels?
- LA binds to channels, inactivating them.
165
A drug will travel through a membrane faster if its… charged or uncharged?
Uncharged
166
What are the two factors that determine whether a drug us charged or uncharged?
1. PKa of drug
2. pH of environment
167
Is LA more charged or uncharged if pKa of LA is low?
Uncharged
168
What two drugs have lower pKa values, allowing them to work quicker?
Lidocaine and articaine
169
What is the working time of lidocaine and articiane?
2-4 mins
170
If the environments pH is low, will the LA be more uncharged or charged?
Charged
171
Which nerve fibres are easiest to block through LA?
C fibres
172
which nerve fibres are hardest to block through LA?
A-alpha fibres
173
What is articiane unique selling point?
High diffusivity
174
Where is articiane metabolised and why?
Plasma, due to its ester component
175
What component of LA extends its duration?
Vasoconstrictor
176
What is the role of preservatives in LA?
To prevent adrenaline from oxidising
177
What is the antagonist used to halt vasoconstriction and anaesthetic, causes LA to wear off?
Phentolamine
178
What vasoconstrictor should not be given to pregnant women? And why?
Felypressin, as it has oxytocin effect so may induce early labour
179
What is the max doses of lidocaine that can be used on a normal healthy adult?
7
180
What is the max doses of mepivaciane that can be used on a normal healthy adult?
4.5
181
What is the max doses of prilocaine/ felypressin that can be used on a normal healthy adult?
6
182
What LA should be avoided if patient has a heart condition?
Lidocaine/ adrenaline
183
What structural component of articiane allows for its high diffusivity?
Thiopene ring
184
When should you not use articiane on a patient?
If they are a new mum who is breastfeeding
185
What is parasthesia?
Physical trauma to nerve trunk
186
What LA should not be used in an IANB due to risk of parasthesia?
Articiane
