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Chemical removal of necrotic periodontal ligament on delayed replanted teeth by sodium hypochlorite: morphological analysis and microhardness indentation test of cementum
Author(s) -
Bai J.,
Qin M.,
Zhao Y. M.,
Huang M. W.,
Ji A. P.
Publication year - 2016
Publication title -
international endodontic journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.988
H-Index - 119
eISSN - 1365-2591
pISSN - 0143-2885
DOI - 10.1111/iej.12467
Subject(s) - cementum , sodium hypochlorite , periodontal fiber , dental cementum , dentistry , indentation hardness , materials science , scanning electron microscope , chemistry , dentin , medicine , composite material , microstructure , organic chemistry
Aim To compare the efficacy of sodium hypochlorite (Na OC l) used at different concentrations and working times for removing necrotic periodontal ligament ( PDL ) from delayed replanted teeth and to observe the effects of Na OC l on surface structure and microhardness of cementum. Methodology A total of 88 healthy premolars with a single root extracted for orthodontic purposes were selected and kept dry at room temperature for 1 h. The teeth were divided into 11 groups: group 1 (control): roots were untreated; group 2: necrotic PDL was removed with gauze; groups 3–11: teeth were immersed in Na OC l at different concentrations (1, 2.5 and 5.25%) and for different working times (5, 10 and 15 min). The specimens in each group were inspected separately for cementum integrity and the presence of PDL remnants by histomorphometric analysis, confocal laser scanning microscopy ( CLSM ) and scanning electron microscopy ( SEM ). Another 14 healthy premolars with roots divided into two pieces were selected for Vickers microhardness indentation tests before and after Na OC l treatment. The data were analysed statistically using Wilcoxon signed‐rank test of two‐related samples ( P = 0.05). Results In teeth treated with 1% Na OC l for 15 min or 5.25% Na OC l for 5 min, the cementum remained morphologically intact without cracks, and PDL remnants were absent. In the 1% Na OC l for 15 min group, the microstructure of cementum was arranged more regularly, as observed ×8000 magnification by SEM . Teeth in each of the other groups displayed cementum damage and/or the presence of PDL remnants. Microhardness tests revealed that treatment with 1% Na OC l for 15 min or 5.25% Na OC l for 5 min significantly decreased microhardness of root cementum ( P < 0.05). Conclusions Use of either 1% Na OC l for 15 min or 5.25% Na OC l for 5 min was effective at removing necrotic PDL from the delayed replanted teeth whilst having a minimal influence on cementum integrity. However, 1% Na OC l for 15 min was less damaging to cementum.