The lesions that involve the furcation region of multirooted teeth may have an endodontic as well as a periodontal origin. Many authors have indicated the interrelationship of the pulp and the periodontium. The infection may be passed between the
two
through the apical and lateral or accessory canals.
Infected deciduous molars display different roentgenographic findings from those of permanent molars. While pathologic changes are seen roentgenographically at the root apex of the permanent molar, the pathologic changes are evidenced by a
radiolucent
zone between the roots in the deciduous molar.
In order to investigate the reasons for this interradicular rarefaction in the deciduous dentition, experimental pulpal exposures were made in the mesiobuccal pulp horn of mandibular second deciduous molars of the kittens with no. 1/2 round bur.
The
kittens were from 10 to 15 weeks of age and were divided into two groups. 10 experimental groups and 1 control group.
The animals were sacrificed in the regular interval from 2 to 20 days after pulpal exposure. The specimens were observed by the light microscope and intraoral standard radiograph.
@ES The results were as follows:
@EN 1. Radiographically, normal interradicular periodontal membrane and inter-radicular bone were shown in control group. In the animal sacrificed after 20 days, a definite thickening of the interradicular periodontal membrane, the destruction of
lamina
dura of furcation area, and interradicular rarefaction were observed.
2. Light-microscopically, operated teeth had accessory canals(75%) running from pulp chamber to the periodontium in the bifurcation region.
3. The pulpal changes of lower 2nd deciduous molar with accessory canal were followed by changes in the periodontium at the opening of accessory canal. These changes led to pathologic destruction of much pulp tissue together with inflammation of
periodontium in the bifurcation. But pathologic change was not seen at root canal and apex.
4. Pulpal inflammatory changes of lower 2nd deciduous molar without accessory canals were confined to the area beneath the exposure or to the coronal part of mesial root canal.
5. In the mandibular 1st and 2nd deciduous molars without pulpal exposure and 1st deciduous molars of experimental group, the pulp, periodontium in the bifurcation, and apical regions were normal.
From the above results, it is suggested that accessory canals play a major role causing furcation lesion following experimental pulpal exposure in deciduous molar in kittens.
|