Bitter taste is mediated by the activation of bitter receptors, which are G protein-coupled and result in an increase in intracellular Ca+2 and subsequent neurotransmitter release, not by the activation of sodium channels as seen in salty taste transduction.

When a tooth has been out of function for an extended period, it can experience changes in the periodontal ligament that supports it. The periodontal ligament is a fibrous connective tissue that connects the tooth to the bone and allows for a certain degree of movement. This movement is essential for the health of the ligament and the surrounding tissues. When a tooth is no longer subjected to the normal forces of biting and chewing, the periodontal ligament fibres can become weak or atrophied.
When this tooth is then used as an abutment for a fixed partial denture (FPD), it is once again exposed to the functional stresses that were previously absent. These stresses can cause traction on the periodontal ligament fibres, leading to pain and discomfort. The pain is mainly due to the sudden reintroduction of forces to the ligament that it is not accustomed to handling.

Toxic dosage of lignocaine with adrenaline is 5 mg/kg body weight.

Bell's palsy is a form of temporary facial paralysis or weakness on one side of the face resulting from damage or trapping of the facial nerve (cranial nerve VII), which is the nerve that controls the muscles of facial expression.

Which of the following is not a theory for local anaesthetic action: None of the above.