Barodontalgia, commonly known as’ tooth squeeze’ and previously known as ‘aerodontalgia’, is pain in a tooth caused by a change in ambient pressure.  It can occur in divers (particularly during deep dives) due to either a void within any part of a tooth or tooth restoration or as a consequence of some other pathology in the tooth or associated structures.

Most of the common oral pathologies have been reported as sources of barodontalgia: dental caries, defective tooth restoration, pulpitis, pulp necrosis, apical periodontitis, periodontal pockets, impacted teeth, and mucous retention cysts.

Sometimes, pressure changes damage teeth rather than just causing pain. This is known as Barotrauma. When the external pressure rises or falls and the trapped air within the void cannot expand or contract to balance the external pressure, the pressure difference on the rigid structure of the tooth can occasionally induce stresses sufficient to fracture the tooth or dislodge a filling.

Teeth undergoing endodontic treatment (root canal therapy)and which have been temporarily sealed have been known to explode from air trapping and expanding on surfacing. This is known as ‘odontocrexis’ and is found to be more common in deep divers using a heliox mixture. Ideally root canal therapy should be completed and no air-filled spaces left in the tooth prior to diving. Full porcelain crowns can also shatter from pressure changes if voids are present beneath them.

Barotitis-media (also known as ‘middle ear barotrauma ‘and ‘ear squeeze’) is an acute or chronic traumatic inflammation in the middle ear space produced by a pressure differential between the air in the tympanic cavity and that of the surrounding atmosphere. The symptoms of barotitis-media range from ear discomfort to intense earache, tinnitus, vertigo with nausea, and hearing loss. URTI (upper respiratory tract infection) predisposes divers to this condition. Barotitis media is unilateral, occurring during or soon after diving ascent. It may involve facial expression muscles and taste sensation from the anterior tongue.

Barosinusitis (also known as ‘sinus barotrauma’ and ‘sinus squeeze’) is an acute or chronic inflammation of one or more of the paranasal sinuses, produced by the development of a pressure difference (usually negative) between the air in the sinus cavity and that of the surrounding atmosphere. It happens more commonly during descent than during ascent in diving.

Alveolar osteitis or Dry socket  is inflammation of the alveolar bone (bony tooth socket)  in the upper or lower jaw as a postoperative complication of tooth extraction. It usually occurs in about 5% of extractions due to failure of blood clot formation or blood clot dislodgement from the socket .This leaves an empty socket where bone is exposed to the oral cavity. Although this condition has no long term sequelae it is quite painful. Divers sucking air through a snorkel or regulator may cause clot dislodgement and subsequent dry socket. Diving should therefore be delayed for at least 2 weeks following tooth extraction.

http://onlinelibrary.wiley.com/doi/10.1111/j.1834-7819.2011.01340.x/full

http://scuba-doc.com/dentprbs.html