Dental Caries: This is the most common cause of toothache, resulting from the bacterial breakdown of tooth enamel, leading to cavities and potentially exposing the dentin or pulp.

Pulpitis: Inflammation of the dental pulp, which can be reversible or irreversible, often caused by deep caries, trauma, or extensive restorations.
Gingivitis or Periodontitis: Inflammation of the gums (gingivitis) or the supporting structures of the teeth (periodontitis), which can cause pain, especially if there is an acute exacerbation or abscess formation.
Dental Abscess: A localized collection of pus in the tissues surrounding the teeth, often resulting from a bacterial infection of the dental pulp or periodontal tissues.
Tooth Fracture: A crack or break in the tooth, which can expose the pulp or dentin, leading to pain.

Acute Apical Periodontitis: An inflammatory condition of the periodontal ligament surrounding the root of a tooth, often caused by bacterial invasion of the pulp, which can lead to severe pain and potentially more serious complications if not addressed.
Cellulitis or Ludwig's Angina: Severe infections of the soft tissues of the face and neck, which can be life-threatening if not promptly treated with antibiotics and supportive care.
Trigeminal Neuralgia: A chronic pain condition that affects the trigeminal nerve, which can cause intense, shock-like or stabbing pain in parts of the face, including the teeth.

Eagle Syndrome: A condition caused by an elongated or calcified styloid process, which can irritate nearby tissues and cause facial and dental pain.
Sinusitis: Inflammation or infection of the sinuses, which can refer pain to the upper teeth due to the proximity of the maxillary sinuses to the roots of these teeth.
Cardiac Issues (e.g., Angina or Myocardial Infarction): Though rare, cardiac conditions can sometimes manifest as tooth or jaw pain, especially if the pain is referred from the heart via shared nerve pathways.