Periapical abscess (a collection of pus around the tooth's root that can cause acute or chronic symptoms)

Pain may have begun recently or be longstanding

Constant pain that worsens when chewing or biting

Normally, the person can precisely identify the involved tooth

Tooth tender when tapped with a metal probe or tongue depressor (percussed) 

Sometimes visible swelling of the gum over the affected root and painful swelling of the adjacent cheek and/or lip

A dentist's examination†

Cavities

Pain that

Usually a visible cavity or a root surface exposed by gum recession or an abrasion

A dentist's examination†

Pericoronitis (usually involving an erupting or partially impacted wisdom tooth)

Constant dull pain, especially when chewing

Visible swelling, redness, and sometimes pus around the affected tooth

Commonly spasms of the chewing muscles (trismus) may occur and limit opening

A dentist's examination†

Sinusitis

Pain in several upper teeth on one side, especially molars and premolars

Sensitivity when chewing and when the upper teeth are tapped (percussed)

Often a nasal discharge and tenderness when the sinus is tapped

Pain when changing positions, especially lowering the head (as when bending down to tie shoe laces) 

A doctor's examination, sometimes with CT of the sinuses

A dentist’s examination if no sinusitis is detected