The effect of chemical and/or mechanical conditioning on the Er:YAG laser-treated root cementum: analysis of surface morphology and periodontal ligament fibroblast attachment.
OBJECTIVE
This study compared the surface morphology as well as the biocompatibility of dental root cementum treated with Er:YAG laser irradiation alone and with the laser irradiation followed by chemical and/or mechanical conditioning.


METHODS
Healthy cementum plates were randomly assigned to the following control and treatment groups: (1) untreated control (C), (2) Er:YAG laser irradiation (L), (3) laser plus tetracycline HCl (TC) placement (L+TP), (4) laser plus TC burnishing (L+TB), (5) laser plus EDTA gel placement (L+EP), (6) laser plus EDTA gel burnishing (L+EB), (7) laser plus saline solution burnishing (L+SB), and (8) laser plus minocycline-HCl paste placement (L+MP). Specimens were subjected to scanning electron microscopy (SEM), histological observation and attachment assay using periodontal ligament (PDL) fibroblasts.


RESULTS
The laser irradiation produced a thin affected layer (5.7 microm thickness) with a superficial microstructure on the cementum surface. The characteristic microstructures of the lased surface were fragile and could be removed by chemical and/or mechanical conditioning treatments. The L+TB group exhibited marked exposure of collagen fibers after removal of the microstructures on the lased surface. The L+EP group presented a peculiar, smooth surface without exposure of collagen fibers and a uniform arrangement of spherical microparticles on the ultra-high magnification of SEM. In cell attachment assay, the L+TB group exhibited the greatest number of attached cells among all the groups, followed by the L+EP, L+SB and control group. The laser alone group exhibited the lowest number of cells.


CONCLUSIONS
The characteristic microstructure of the root cementum surface after Er:YAG laser irradiation has a tendency to hinder the early attachment of PDL cells. However, chemical and/or mechanical root conditioning treatment may improve and increase the biocompatibility of the Er:YAG laser-treated root cementum by removing the microstructures of the surface and/or further exposing the collagen fibers.
Maruyama
Hiroaki
H
Section of Periodontology, Department of Hard Tissue Engineering, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. maruyama.peri@tmd.ac.jp
Aoki
Akira
A
Sasaki
Katia Miyuki
KM
Takasaki
Aristeo Atsushi
AA
Iwasaki
Kengo
K
Ichinose
Shizuko
S
Oda
Shigeru
S
Ishikawa
Isao
I
Izumi
Yuichi
Y
D002448:Cell Adhesion / Q000187:drug effects / Q000528:radiation effects; D003739:Dental Cementum / Q000187:drug effects / Q000528:radiation effects* / Q000648:ultrastructure; D003775:Dental Polishing; D005347:Fibroblasts / Q000502:physiology; D006801:Humans; D053844:Lasers, Solid-State; D010513:Periodontal Ligament / Q000473:pathology; D013499:Surface Properties / Q000187:drug effects / Q000528:radiation effects; D014016:Tissue Conditioning, Dental / Q000379:methods*; D046509:Tissue Culture Techniques