This protocol is for a clinical trial to evaluate the reliability of the bite fork as a diagnostic instrument in subjects with pulpal necrosis and apical periodontitis.

This clinical trial consists of two parts. We will first use the bite fork in normal volunteers to evaluate its test-retest and inter-rater reliability. We will then use the bite fork in subjects with differing endodontic diagnoses and compare these results with the standard clinical diagnostic test (percussion).

Inclusion Criteria:

1. Patient must be at least 16 years of age.
2. Clinical indication for non-surgical root canal therapy (NSRCT).
3. 1st or 2nd maxillary or mandibular molar or premolar
4. Diagnosis must be chronic apical periodontitis (CAP) with or without symptoms.
5. Intact, mature apices.
6. American Society of Anesthesiologists (ASA) I or II.

Exclusion Criteria:

1. Failure to meet any of the above
2. Previous NSRCT
3. Previous pulpotomy or pulpectomy
4. Suppurative apical periodontitis
5. Patients taking medications which can affect their pain rating or medications which affect their immune system (such as glucocorticoids)

Normal subjects and patients with orofacial pain presenting in the dental clinic.