Electronic root canal length measurement before and after experimentally induced pulpitis and apical periodontitis in dogs

Abstract

The aim of the study was to examine the influence of the state of the pulp and apical periodontium on the results of electronic root canal length measurement (ERCLM) with a resistance measuring device in dogs. Pulpitis and apical periodontitis were induced by pulp exposure and contamination by the oral flora in the premolar teeth of six mongrel dogs, comprising four experimental groups (36 root canals). In a control group, measured lengths of teeth with uninfected pulps were performed on the first experimental day (44 root canals). In all animals the ERCLMs were performed on teeth with healthy pulps, and at the end of the experimental period (20, 35, 50 and 65 days) following pulp exposure. The point of measuring canal lengths was the anatomical obstacle above the apical delta. Electronically measured lengths (EML) were compared between each other and with the root canal length established by tactile-sense measurement verified radiographically. The EMLs were less accurate in teeth with healthy pulps and teeth with pulpitis in the third experimental group (dif=2.27 x 2.65 mm(2); t test, p<0.05), while they were most precise after 65 days in teeth with completely necrotic pulp and established chronic apical periodontitis (dif=0.54 x 1.36 mm(2); t test, p>0.05). These results suggest that the state of the pulp and periapical tissue may have an influence on the ERCLM.

A histopathological study of the pulp of dogs’ teeth after induction of experimental pulp inflammation for different periods of time

“…different types of restoration) (Stanley, 1968a,b). Different methods of inducing pulpitis experimentally have been introduced, for example preparing deep cavities and leaving them unfilled (Mjör & Tronstad, 1972), preparing deep cavities and filling them with soft carious dentin from freshly extracted human teeth (Sazak et al , 1996), preparing deep cavities and filling them with gutta‐percha temporary stopping material (Mjör & Tronstad, 1972), preparing cavities without coolant (Takahashi, 1990), placing fresh Streptococcus mutans into occlusal cavities with a small pulpal exposure (Cleaton‐Jones et al , 2007) and pulp exposure and contamination by the oral flora (Kovasevic et al , 2006). Mjör and Tronstad (1972) demonstrated that preparing deep class ν cavities in the buccal surface of the teeth of monkeys, followed by the insertion of carious dentin from freshly extracted human teeth into the cavities and finally filling the cavities with amalgam for 8 days, is a reliable method of experimental induction of pulpitis.…”