Techniques for local anasthesia in dentistry

Techniques for local anasthesia in dentistry

Dr.Mohamed Rhael Ali2016 - 2017

local anasthesia techniques

Topical

Infiltration

Regional (block)

Topical ( surface ) anasthesia

• Obtained by application of anasthetic agent to skin or mucosa to anasthetize superfacial nerve ending

• Its used mainly prior to injection

• Sprays containing appropriate local anasthesia mostly suitable prior to injection due to its rapid onset time

Topical ( surface ) anasthesia

• Mainly used spray LA consist from 10% lidocaine hydrochloride .

• The onset of time about 1 minute and the duration about 10 min .

• Ointment 5% lidocaine hydrochloride can be used for the same purpose but it take 3-4 minutes to produce surface anasthesia .

• Ethyl chloride spray can be used to produce rapid surface anasthesia by refrigeration , this technique used mainly prior to incision of drainage of pus .

Infiltration anasthesia

Deposition of local anasthesia near the nerve ending by which the LA diffuse through the tissue to reach the nerve

fibers

Subdivided in to several techniques :

a. Submucosal injection LA solusion deposited just beneath the mucous

membrane , its suitable for soft tissue anasthetization but not effective for pulp anasthetization


b. Supra-periosteal injection

• This technique effective in maxilla• LA solution deposited above the periosteum • It infiltrate through the periosteum , cortical plate ,

medullary bone and reach nerve fiber , so its used to anasthetize dental pulp .

• This technique is the most used technique in dentistry • LA should deposited near the root apex


c. Sub-periosteal injection

• Here the LA solution deposited between the periosteum and the cortical plate .

• Its painful technique because periosteum tense and firmly attached to the cortical bone plate



d. Intra-osseuous injection • Rarely used technique .• LA solution deposited within the

medullary bone .• This procedure carried out by the use of

bone drills and needles especially designed for this purpose .

Regional anasthesia (block)

Regional anasthesia• Deposition of local anasthetic

solution near a nerve trunk so producing anasthesia for area supplied by this nerve .

• It can be used in maxilla but its main indication in the mandible because infiltration technique in the mandible mainly ineffective due to dense cortical bone plate .

local anasthesia in maxilla

Anasthesia of upper molars teeth• The pulp of all upper molars innervated by branches from

superior posterior alveolar nerve (except the mesiobuccal root of first molar )

• Theses nerves also responsible for innervation of periosteum and buccal gingiva in molars region .

• Deposition of anasthesia close to the nerve after it leaves its bony canal will produce regional anasthesia but its rarely used because it carries a risk of damage to the pterygoid venous plexus

Technique for posterior superior alveolar nerve block

• 1. partially open the patient mouth• 2. retract the patients cheek• 3. insert the needle into the height of the

mucobuccal fold over the second molar • 4. Advance the needle slowly in an upward ,

inward ,and backward direction in one movement

• 5. deposite anasthetic solution (about 1-1.8 ml) and then withdraw the syringe

Infiltration technique

1. Hold the syringe with the long axis of the tooth

2.Insert the needle into the height of the mucobuccal fold over the target tooth

3. Advance the needle for a few millimeters and inject slowly about third the cartidge and then

withdraw the syringe slowly

In block technique the whole region supplied by superior posterior alveolar nerve will be

anasthetize while in infiltration technique a limited area of specific target tooth will be

anasthetized

Anasthesia for upper premolar teeth

• The mesiobuccal root of the upper first molar and both premolars and buccal supporting tissue and mucoperiosteum related to them all are innervated by middle superior alveolar nerve .

• So infiltration technique to this nerve will be sufficient to anasthetize all these structures .

Anasthesia for upper anterior teeth

The upper anterior teeth and its supporting tissues and mucoperiosteum related to them are innervated via anterior superior dental

nerve so infiltration technique will be sufficient

Note :

In conservative treatment the pulp only needed to be anasthetized while in tooth extraction the pulp , bone ,periosteum and the gingiva (labial

and palatal ) should be anasthetized

Anasthesia for palatal mucosa

Palatal mucosa are tense and closely attached to the underlying bone so :

• Injection will need great pressure • Injection usually painful . pain can be reduced by

inserting the needle with the bevel facing the bone and as near as possible at right angle to the vault of the palat

Palatal anasthesia can be achieved by block injection: to the greater palatine nerve in the posterior part of hard palat

distal to the second molar about 1 cm toward the midline and

nasopalatine block in the anterior part of hard palat (incisive foramen) in the midline of the palate ,about 1 cm

posterior to the maxillary central incisor. Or

by infiltration : in which the solution is deposited in the palatal tissue adjacent to the target tooth .

Anasthesia for palatal mucosa

Infiltration technique for the palat

Infra - orbital block injection Rarely used because infiltration technique so effective in maxilla .

Usually indicated when numerous extration or extensive surgery are to be done in maxillary anterior teeth .

Also indicated when infiltration technique precluded by presence of infection at the injection site .

This technique provide ansthesia for centrals, lateral incisors,canine , premolars and supporting structures .

Techniques :

Intra –oral Extra – oral

Infra - orbital block injection

Intra-oral approach : • Most popular technique .• Infra-orbital ridge palpated and the infraorbital notch

determined . • Infrorbital foramen lie directly below below this notch • lip reflectd and long needle inserted in to a depth

about 1.5-2 cm in to the mucous membrane over second premolar .

• About I ml of LA given


• Extra oral approach


Anasthesia of the upper deciduous teeth

• Infiltration technique highly effective because the labio-buccal bone plate are thin and perforated by numerous vascular canals .

• Care should be taken to estimate the length of roots and depth of injecion.

local ansthesia in mandible

local ansthesia in mandible

• Infiltration techniques are of limited value due to the dense cortical bone of mandible

• Block technique for inferior alveolar nerve is the preffered technique

Boundaries of the pterygomandibular space

Inferior dental block (IDB)

• The success of this technique depend on the accuracy of deposition of the solution .

• This technique ansathetize the inferior alveolar nerve and its terminal branches (mental and incisive nerve)

Technique for IDB

Technique for IDB

Technique for IDB

Notes• The dimentions and shape of the mandible may vary in patients of

differing race , size , age so the width of the ascending ramus and the position of the mandibular foramen may vary between individuals.

• Its better to palpate the anterior and posterior border of the ascending ramus by the thumb and index fingers and the needle directed midway between the two fingers

• Bilateral IDB should be avoided as possible ( patient feel discomfort , difficulty in swallow and to avoid self injury to the anasthetized tissues)

• Lingual nerve can be asnasthetized by infiltration technique by injection of about 0.5 ml of the solution in the lingual sulcus adjacent to the target tooth

Long buccal nerve block

• Can achieved by sub-mucosal injection of local ansthesia just posterior and buccal to the last molar .

• Infiltration technique achieved by deposition of the solution in the muco-buccal fold adjacent to the target tooth .

Notes • When the long buccal nerve anasthetized the

patient rarely experiences any symptoms due to the small size of the anasthetized area .

• The depth of penetration of the needle not more than 2-4 mm .

Anasthesia of the lower anterior teeth

lower anterior teeth usually have innervation from both sides of dental nerve by anastomosing its terminal branches at these region.

Unilateral IDB usually not enough

Infiltration technique is effective because the labial bone plate at this region are thinner and more porous than other parts of mandible .

Mental nerve block

• Can be used to anasthetize the premolars, canine and the incisors of that side

Anasthesia of the lower deciduous teeth

Infiltration technique highly effective

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Health & Medicine

Techniques for local anasthesia in dentistry