General anaesthetic refers to being "put to sleep." During GA, you are unconscious.
General anaesthetic tends to be used as a last resort in the management of dental fear and anxiety for routine dental treatment due to the high effectiveness of IV sedation for nearly everyone.
Whilst the risk of serious complications is very small, each general anaesthetic does carry a certain amount of risk due to the depression of the cardiovascular and respiratory systems. When considered necessary, it should be given in the safest way possible. This means that GA is only available in hospitals and specialist clinics where the necessary safety equipment is available.
When is GA used?
GA can be useful and indicated in the following situations
IV sedation works for around 95% of extremely anxious people but there will always be a few people for whom it doesn't work, either because you find it impossible to cooperate even when sedated or because you have a high tolerance to the drugs used for IV sedation. This appears to be more common if you've been taking similar drugs long term for other health conditions. In this case GA may be the best.
For more traumatic procedures such as the surgical removal of wisdom teeth that are more deeply impacted in bone, GA may be preferable. If it's extractions that terrify you, it may be possible to put you to sleep for the extractions but have the remainder of your treatment done under IV sedation or nitrous oxide with local anaesthetic.