West China Journal of Stomatology

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A comparative study on apexification using different kinds of materials in dogs

Huang Rui1, Liu Peng2, Xiao Maode3, Zhou Zhi1.   

  1. 1. Dept. of Conservative Dentistry and Endodontics, The Affiliated Hospital of Stomatology, Chongqing Medical University; Chongqing Research Center for Oral Diseases and Biomedical Science, Chongqing 401147, China; 2. Dept. of Radiology, The Affiliated Hospital of Stomatology, Chongqing Medical University; Chongqing Research Center for Oral Diseases and Biomedical Science, Chongqing 401147, China; 3. Dept. of  Stomatology, The First Traditional Chinese Medical Hospital of Jiulongpo District, Chongqing 400080, China
  • Online:2013-08-01 Published:2013-08-01

Abstract:

Objective   To compare the efficacy of hydroxyapatite(HA), calcium hydroxide(CH) and Vitapex on root formation of immature teeth of dogs. Methods  Sixteen roots of permanent incisors in two dogs(about five to six months old) were used. After the pulpectomy, roots were randomly divided into four groups. Group A, B and C were experimental groups and filled with HA, CH and Vitapex, respectively. Group D was control group and filled with AH plus. The changes of root length and apical areas were measured by cone beam CT(CBCT), meanwhile, paraffin sections with hematine-eosin(HE) staining were used to observe the shape of root tips; frozen sections with alkaline phosphatase (ALP) staining were used to observe the osteoplastic activity of cells. Results  1)CBCT showed that four weeks later, all roots in every groups became longer(P<0.05), and the apical areas in three experimental groups decreased(P<0.05). However, eight weeks later, high density image could be detected in every root. 2)Histological examination showed that there was no inflammation in every group, and after four weeks, none of apicals were closed, but partial cementum and peridental membrane had extended into canals. After eight weeks, a complete cementum barrier and an intensive distribution of positive cells of ALP staining could be seen in group A, however, some spaces could be seen in the cementum barrier of group B and C, which were filled with periodontal membranes, and the positive cells of ALP staining were dispersed. Moreover, scattered cementum, cementoid and abundance fiber or blood vessels could be seen in group D, in which ALP staining was negative. Conclusion  The root formation of immature teeth can go on after pulpectomy when there is no inflammation, the tissue source is probably the periodontal membrane, and HA which can induce root formation faster is a better material in the apexification.

Key words:  apexification, cone beam CT, hydroxyapatite, alkaline phosphatase, periodontal membrane