how to overcome failed

8/2/2019 How to Overcome Failed

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Dr. Aneeqa Yaqub


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Overview

Understanding the reasons Operator dependent

Patient dependent

Approach to overcome failure

Conclusion


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Reasons of failure Operator dependent

Choice of solution

Poor technique

Patient dependent

Anatomical

Pathological Psychological.


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Operator dependent variablesThis means:

poor technique

Administration of insufficient solution

use of an inappropriate anesthetic solution

Choice of solution

o The most appropriate local anesthetic solution for mostdental procedures is lignocaine with adrenaline

o In some medically-compromised patients adrenaline-freesolutions may be preferred


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Poor technique:

o The most likely defect in technique is faulty needle

placemento Failure to aspirate before injection

o Speed at which the solution is deposited

o Poor technique usually relates to mandibular anesthesia,

specifically failed inferior alveolar nerve block injections


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Patient Dependent VariablesAnatomical causes of failure of anesthesia

o Individual variations in the position of nerves andforamina

Foramina do not have a consistent location betweenpatients

Available radiographs may be helpful in anticipating thissituation

oAccessory nerve supply

Accessory nerve supply can lead to failure of anesthesiafollowing both infiltration and regional block methods


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Tooth Main supply Accessory

supply

Accessory

supplycountered by:

Maxillary Superior alveolarnerve

Greater palatine/Nasopalatine

Palatal block orpalatal infiltration

Mandibular Inferior alveolarnerve

Long buccal nerve Long buccal blockor buccalinfiltration

Lingual nerve Lingual block orlingual infiltration

Mylohyoid nerve High block orlingual infiltration

Auriculo-temporalnerve

High block

Upper cervicalnerves

Buccal and lingualinfiltrations


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o Barriers to anesthetic diffusion

The most obvious barrier is the thick cortical plate of themandibular alveolus

The first molar region in the adult maxilla occasionallypresents a similar problem

Pathological causes of failure of anesthesia

o Factors precluding access

There is trismus due to

Infection Trauma

Anatomical changes due to surgery


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It may be prudent to allow the trismus to resolve prior todental treatment

o Inflammation

Teeth with inflamed pulps can be difficult to anaesthetize

How inflammation induces results in failure of anesthesia:

Low pH

Wash-out effect

Nerves become hyperalgesic

The maximum volume of local anesthetic is given,

predetermined safe maximum dose should not beexceeded

In patients, where early treatment can be deferred,NSAIDs can be given to reduce inflammation


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Psychological causes of failure

o There are undoubtedly patients who do not do well withlocal anesthesia, because of :

Fear

Apprehension Drugs

o Sedative techniques can be helpful as successful anesthesiais easier to achieve

o Benzodiazepines offer the added bonus of reducing localanesthetic toxicity


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An approach to the failed localanesthetic case

When an initial local anesthetic fails the besttreatment is to repeat the injection

The flow diagrams for management of failure in bothjaws


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Buccal Infiltration

Fail

Success

Buccal And Palatal

Infiltration

Success

Fail

Posterior SuperiorAlveolar/

Infraorbital Nerve

Block

Fail

Success

Intraligamentary/Intraosseous/

Intrapulpal

Success

Maxilla


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I.A.N block

fail

success

Higher I.A.N block

success

fail

Akinosi block/ Gow-Gates block

Fail

Success

Buccal and lingual

infiltration

Intraligamentary/Intraosseous/

Intrapulpalsuccess

Mandible


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Conclusion

Failed local anesthesia is a feature of dental practice

Understanding of the reasons for failure, should helpovercome most cases encountered in practice

how to overcome failed

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