Effect of Intracanal Medication on the Healing of the Pulp or Periapical Tissues After Pulpectomy or Pulpotomy

1990 Fiscal Year Final Research Report Summary

• Project/Area Number: 63570900
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Conservative dentistry
• Research Institution: Aichi Gakuin University
• Principal Investigator: NAKAMURA Hiroshi Aichi-Gakuin University school of Dentistry Professor, 歯学部, 教授 (40064878)
• Co-Investigator(Kenkyū-buntansha): MASEKI Tomoharu Aichi-Gakuin University school of Dentistry lecturer, 歯学部, 助手 (30201768) ; HYODO Kiminori Aichi-Gakuin University school of Dentistry lecturer, 歯学部, 助手 (90201730)
• Project Period (FY): 1988 – 1990
• Keywords: Formalin-creosote / pulpectomy / pulpotomy / Rat / Experimental pathology

Research Abstract

The purpose of the present study was to investigate histologically and histometrically the effect of formalin-creosote (FC) on the pulp and the periapical tissues after pulpectomy or pulpotomy in rats.
Experiment I. Seventy-five rats were divided into 3 groups. In all Groups, the mesial root of the right mandibular first molar was removed. After pulpectomy, in Group A, a paper cone containing saline was inserted into the root canal. In Group B, a paper cone containing FC was inserted. The animals were killed at 1, 3, 7, 14 and 28 days. The periapical tissues were examined histologically and histometrically.
Experiment II. One hundred rats were divided into 4 Groups. After pulpotomy, in Group a, a paper cone containing saline was inserted into the root canal. In Group b, a paper cone containing FC was inserted. In Group c and d, the procedures were performed in the same manner as in Group A and B. The results were as follows.
Histologically, in Group A and c, severe inflammation was observ ed in the periapical tissues at 1 and 3 days. Inflammation became slight and fibrous tissue increased at 14 and 28 days. In Group B and d, severe inflammation was observed in the periapical tissues at 1 and 3 days. Inflammation became moderate at 7 and 14 days. Inflammation became slight at 28 days. In Group C, severe inflammation was found in the periapical tissues at 1, 3 and 7 days. Moderate inflammation remained and fibrous tissues proliferation was seen at 14 and 28 days. The granulation tissue in Group b increased significantly compared with those in Group a at 7 days.
Histometrically, vertical length and area of the apical periodontal ligament in Group B and C increased significantly compared with those in Group A at 14 and 28 days. Inflammatory cells in the granulation tissue in Group B and C decreased significantly compared with those in Group A at 7, 14 and 28 days.
The results of the present study indicated that FC delayed the healing of the periapical tissues after pulpectomy or pulpotomy.