Pain Control in Dentistry

Study Notes

A philosopher, according to William Shakespeare, cannot endure a toothache patiently.

Administration of local anaesthesia to all tissues in the operating site is recommended in certain patients to eliminate pain and reduce salivation associated with tooth preparation and restoration.

A therapeutic dose of a drug is the smallest amount that is effective when properly administered and does not cause adverse reactions.
An overdose of a drug is an excessive amount that results in an overly elevated local accumulation or blood level of the drug, causing adverse reactions.

Each 1.8 ml cartridge contains anesthetic, with or without a vasoconstrictor (e.g. lidocaine 2% [anesthetic] with epinephrine 1:100,000 [vasoconstrictor], lidocaine 2% plain [no vasoconstrictor]).
The number of permissible cartridges increases as body weight increases.
The maximum recommended dose of 2% lidocaine with epinephrine 1:100,000 is 4.4 mg/kg.

Pulpal (deep) anaesthesia varies from 30 to 90 or more minutes.
Soft-tissue anaesthesia varies from 1 to 9 h, depending on the specific agent and whether or not a vasoconstrictor is included.

Patients with stage 1 hypertension (systolic pressure less than 140 mmHg, diastolic pressure less than 90 mmHg) are good candidates for all dental procedures.
Patients with blood pressure consistently greater than stage 1 hypertension (stage 2 hypertension) should be referred to their physicians, particularly if the elevation is greater than 20 mmHg.
Pulse rates less than 60 beats per minute (beats/min) or greater than 110 beats/min require further questioning.

The central nervous system (CNS) is more easily affected by overdose of injected anesthetic drugs than the cardiovascular system.
Anesthetics depress the CNS, but when administered properly for local anaesthesia, little or no clinical evidence of depression is encountered.
Overdose symptoms include excitation (e.g. talkativeness, apprehension, sweating, elevated blood pressure and heart rate, elevated respiratory rate) or drowsiness.