Apoptosis in pulp elimination during physiological root resorption in human primary teeth.
Pulp samples of 50 healthy human teeth with indication for extraction were examined to evaluate the role of apoptosis in pulp elimination during physiological root resorption. Two groups were formed: a test group (n=30) composed of pulp samples of primary teeth with physiological root resorption and a control group (n=20) composed of pulp samples of permanent maxillary third molars. Morphological evidence of apoptosis as well as in situ detection of cellular DNA fragmentation by TUNEL assay and detection of internucleosomal pattern of fragmentation of the genomic DNA by electrophoresis were observed. The apoptotic index of the primary tooth group was significantly higher than that of the permanent tooth group (51.01 +/- 0.52 versus 25.32 +/- 0.68) (p<0.001). TUNEL reaction showed intense and diffuse labeling in the pulp samples of primary teeth, which were discrete in the controls. Intense DNA internucleosomal fragmentation, a specific pattern for apoptosis, was observed in primary tooth pulps DNA by electrophoresis, in the permanent tooth pulps this pattern fragmentation of the genomic DNA for apoptosis were not present. These results seem to indicate a role of apoptosis in pulp elimination during the physiological root resorption of human primary teeth.
Department of General Pathology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil. villelalu@yahoo.com.br
Luciana Villela
LV
Rodrigues
Anilton César
AC
Vasconcelos
Pedro Alves
PA
Campos
Juliana Massote Caldeira
JM
Brant
D000704:Analysis of Variance; D017209:Apoptosis / Q000502:physiology*; D053938:DNA Fragmentation; D003782:Dental Pulp / Q000166:cytology / Q000502:physiology*; D006801:Humans; D020287:In Situ Nick-End Labeling; D008964:Molar, Third; D009707:Nucleosomes; D012016:Reference Values; D012391:Root Resorption / Q000473:pathology*; D018709:Statistics, Nonparametric; D014080:Tooth Exfoliation / Q000473:pathology*; D014094:Tooth, Deciduous
D009707:Nucleosomes