CLINIC THEORY Unit 7 Topical and Local Anesthetic

Anesthesia

temporary loss of feeling or sensation

Anesthetic

medication that produces the temporary loss of feeling or sensation

Induction

• time from injection, to effective anesthesia

• the length of time from injection to complete conduction blockage

Innervation

supply or distribution of nerves to specific body part

Topical Anesthesia

provides a temporary numbing effect on nerve endings located near the surface of the oral mucosa, the drugs in _____ are concentrated to allow penetration of the mucous membranes and action at the nerve endings.

Local Anesthetic

most frequently used form of pain control in dentistry. It is safe, dependable, effective, and suitable for virtually all forms of dental treatment and it is not irritating to tissues. It has minimal toxicity, rapid onset, and eliminates pain during a procedure.

Local anesthesia

is obtained by injecting an anesthetic solution near a nerve where treatment is to take place

Electronic Anesthesia

• non invasive form

• blocks pain using a low current of electricity

• contact pads targeted directly to the nerve bundle at the root of the tooth

• hand pads on backs of hands and third pad placed intra-orally

• area is isolated and dried, pad attached to the lingual side 3-5mm from the gingival margin

• client has control in activating the unit and gradually increasing the level of the pain-blocking signal

Inhalation sedation

• nitrous oxide/oxygen analgesia

• may be the safest type of sedation in dentistry

• produces a Stage 1 anesthesia/analgesia by using a combination of nitrous oxide and oxygen gases

• client inhales these gases through a nosepiece and feels the effect almost immediately

• produces a pleasant, relaxing experience

• easy onset, minimal side effects and rapid recovery

• tasteless, sweet-smelling, colourless gas in a blue cylinder

nose piece

nasal inhalers through which client breathes (rubber can be sterilized)

scavenger system

reduces the amount of N2O releases into treatment room

antianxiety agents

• in large doses these can produce sleep, sedation, and anesthesia

• can be administered orally, intravenously, or by inhalation

• this is used for clients who are nervous, long/difficult procedures, mentally challenged, and for very young children that need extensive treatment

Intravenous sedation - Conscious sedation IV

• Results in a minimally depressed level of consciousness.

• Client can maintain an open airway

• only given and monitored by someone who is trained and certified (Oral surgeon or Periodontist)

• Have registered nurse to administer

• Feels the effect almost immediately

General Anesthesia

• A controlled state of unconsciousness

• loss of protective reflexes  ie. lose ability to maintain an airway independently

• Stage III

• (Stage one is induction, stage two is excitement and possible uncontrolled movements)

Anesthesiologist

are physicians who specialized in general anesthesia

Local anesthetic with epinephrine

cannot be used with patients who have heart disease, hypertension, and hyperthyroid disease

Local anesthetic amide

cannot be used for patients who have impaired liver function

Topical anesthetic

cannot be used for patients who have open lesions and certain food allergies

15 seconds to 1-2 minutes

for effectiveness of topical anesthetic ointments, these must remain on the site of injection for how long?

Liquid and spray topical anesthetic

are applied to larger surfaces of the mouth. For example, back of the throat to desensitize gag reflex

Topical patch

• new product that works within 10 seconds, used for injections and alleviates discomfort from denture sores and ulcers

• vary in concentrations of 5-20% of active ingredients

Esters

• are usually used as topical anesthetics

• an alcohol based and soluble in water

• have a greater potential of adverse allergic reaction

• are metabolized in plasma

• quickly absorbed

Benzocaine

active ingredient of esters

Lidocaine

active ingredient of amides

Amides

• absorbed slowly

• low incidence of allergic reaction

• metabolized in the liver

• cannot be used for clients with impaired liver function

• white, sloughing mucosa

• seizures, CNS depression, increased BP and pulse

overdose to anesthetic agents

Trigeminal nerve

primary source of innervation for the oral cavity, it has three divisions: ophthalmic, maxillary, and mandibular

Maxillary division

supplies the maxillary teeth, periosteum, mucous membrane, maxillary sinuses, and soft palate.

Maxillary division subdivides into

• Nasopalatine nerve

• greater palatine nerve

• anterior superior alveolar nerve

• middle superior alveolar nerve

• posterior superior alveolar nerve

Nasopalatine nerve

• Passes through the incisive foramen

• supplies the mucoperiosteum palatal to the maxillary anterior teeth

Greater palatine nerve

• Passes through the posterior palatine foramen and forward over the palate

• Supplies mucoperiosteum, intermingling with the nasopalatine nerve

Anterior Superior Alveolar nerve

• Supplies the maxillary central, lateral and cuspid teeth (canines) and their periodontal membranes and gingiva

• Also supplies the maxillary sinus

Middle Superior Alveolar nerve

• Supplies the maxillary first and second premolars, the mesiobuccal root of the maxillary first molar, and the maxillary sinus.

Posterior Superior Alveolar nerve

• Supplies the other roots of the maxillary first molar and the maxillary second and third molars

• Branches forward to serve the lateral wall of the maxillary sinus

Buccal nerve

supplies branches to the _______ mucous membrane and to the mucoperiosteum of the mandibular molars

Lingual nerve

supplies the anterior two thirds of the tongue and gives off branches to supply the _____ mucous membrane and mucoperiosteum.

Inferior alveolar nerve

divides into mylohyoid nerve, small dental nerve, mental nerve, and incisive nerve

mylohyoid nerve

supplies ______ muscles and the anterior belly of the digastric muscle

small dental nerve

supply the molar and premolar teeth, alveolar process & periosteum

mental nerve

moves outward and anteriorly through the ____ foramen and supplies the chin and mucous membrane of the lower lip

incisive nerve

 continues anteriorly within the bone and gives off small branches to supply the _____ teeth

Vasoconstrictors

• function is to slow down the intake of an anesthetic agent and increase the duration of the action

• prolongs the effect of the anesthetic by decreasing blood flow in the area of injection

• the smaller the ratio, the higher the percentage of _______ in the anesthetic agent.

duration

is the time from induction until the reversal is complete

60-180 minutes

short acting

120-240 minutes

intermediate acting

240-540 minutes

long acting

nerve block

anesthetic deposited close to main nerve trunk for quadrant dentistry

palatal anesthesia

• common ____ injections if necessary, are the anterior or greater palatine nerve block (post palate) or the nasopalatine nerve block (ant palate)

• these injections can be particularly sensitive for the client.

Infiltration Anesthesia

• Solution is injected directly into the tissue at the site of the dental procedure

• Generally used for maxillary teeth because of the porousnature  of the alveolar cancellous bone – solution can diffuse through bone and reach apices

• May be used as a secondary  injection to block gingival tissues surrounding the mandibular teeth

• ________ of anesthetic with a vasoconstrictor is used to minimize bleeding

Field Block

• injection of anesthetic near a major nerve

• usually involves deposit of anesthetic at the apex of a tooth when only one tooth and the surrounding area need to be anesthetized (could involve 2-3 teeth)

• most commonly used in maxilla or in the mandibular anterior

Block Anesthesia

• Mandibular bone is compact and dense and therefore, anesthetic doesn’t diffuse as easily through it

• usually required for most mandibular teeth

• method of injection that would provide anesthesia to an entire quadrant

incisive nerve block

If anterior teeth or premolars require anesthesia, an __________ is given at the mental foramen

Periodontal Ligament Injection

• This is an alternative infiltration technique that involves injection  of the anesthetic solution under pressure directly into the _____________ and surrounding tissues

• Used as an addition to other techniques

Thumb Ring, Finger Grip, and Finger Bar

allows the  dentist to control the syringe firmly and aspirate with one hand

Harpoon

• a sharp hook that locks into the rubber stopper of the anesthetic cartridge so the stopper can be retracted by pulling on the piston rod

• this makes aspiration possible

Piston Rod 

pushes the rubber stopper of the cartridge and forces solution out through the needle

Barrel of the Syringe 

firmly holds cartridge in place – loaded through open side, window on other side allows dentist to watch for blood during aspiration

Threaded Tip 

• needle is attached to syringe on the _______

• cartridge end of needle passes through the small opening in the centre of the _________, puncturing the rubber diaphragm of anesthetic cartridge

rubber or silicone

Anesthetic Cartridge/ Carpule have a ______ stopper at one end and an aluminum cap with a rubber diaphragm at the other end

blister packs

Anesthetic Cartridge/ Carpule are supplied in _______ sterilized and sealed.

two-part plastic covering

disposable needles are sterile, protected by a ________________

cartridge end

is the shorter end –  it fits through the threaded tip of the syringe and punctures the rubber diaphragm

Needle Hub

• made of self-threading plastic or pre-threaded metal

• attaches needle to the threaded tip of syringe

Injection End

• protected by the needle guard and is either 1 inch or 1 and 5/8 inches in length

• usually, the short (1 inch) is used for infiltration and the long (1  5/8) is used for block anesthesia

Lumen

hollow centre of the needle

Gauge

• thickness/size of needle

• larger the number, the thinner the needle

• the smaller the number, the thicker the needle

alter the function of vital organs, notably, the heart

If local anesthetic is injected directly into a blood vessel it can

Paresthesia

• a condition in which numbness lasts after the effects of the local anesthetic solutions should have worn off

• use of contaminated anesthetic solution

• trauma to nerve sheath during injection or surgery

• hemorrhage (bleeding) into or around the nerve sheath