Authors: Trope M, Tronstad L, Rosenberg ES, Listgarten M.
Title: Darkfield microscopy as a diagnostic aid in differentiating exudates from endodontic and periodontal abscesses.
Journal: J Endod
Date: Jan 1988
Citation: 14(1):35-8
Category: Endodontic-Periodontal Relationships
Evidence-based Ranking: 4
Purpose/ Objectives: Describes two cases in which the chairside darkfield microscopic spirochete count was valuable aid in differentiating periodontic abscesses from Endodontic abscesses.

Discussion: Case 1: 70-yr-old Caucasian male presented with chief complaint of extremely loose tooth and bad taste in his mouth. The radiographic examination revealed a lower right central incisor with a large radiolucency almost surrounding the entire root. The right central incisor and all neighboring teeth responded negative to pulp testing. The tooth was not painful to percussion and to palpation but was extremely mobile. Periodontal probing revealed a broad lingual pocket extending from the mesiolingual to distolingual line angle. Buccally, periodontal probing was within normal limits, but a sinus tract was present in the alveolar mucosa. Darkfield microscopic analysis showed less than 10% spirochetes, indicating a lesion of Endodontic origin. Therefore, only endodontic therapy was performed. After 6 months there was almost complete resolution of the area. Case 2: 39-yr-old Caucasian man with chief complaint of constant pain in the maxillary left central incisor. The radiographic examination reveled an apical radiolucency. Normal probing depth except the mid lingual with a narrow pocket and a #30 gutta-percha point could be placed in the lingual surface of the tooth and traced to the apical radiolucency. Pulp sensitivity could not be accurately tested due to the “unbearable pain” that the patient was experiencing. All surrounding teeth tested vital. In this case darkfield analysis showed a range of 30 to 60% spirochetes, indicating that the lesion of periodontal origin. Scaling and curettage was done on the diseased tooth. At the 1 wk follow up, patient was asymptomatic.

Author’s Conclusion: Percentage of spirochetes in the microbial flora, as determined in darkfield microscopy, may be of value in the differential diagnosis of periodontal and Endodontic abscesses.

Reviewer’s Comments: An interesting study, however I am not sure if chairside darkfield microscopic analysis would be simple to carry out.