Effect of laser-induced dentin modifications on periodontal fibroblasts and osteoblasts: a new in vitro model.
BACKGROUND
The erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser has been shown to be a promising tool for root treatment in periodontitis, but little information is available regarding the surface characteristics after this treatment, mainly because it is difficult to obtain standardized dentin samples for in vitro studies.


METHODS
Commercially available standardized dentin disks were treated with an Er:YAG laser at different settings and used as a substrate for human primary osteoblastic cells (hOBs) and periodontal ligament fibroblasts (PLFs). Cell proliferation on untreated dentin was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay after 3, 6, 12, 24, and 48 hours of culture. The effects of the laser on dentin and cell morphology on treated and untreated samples were investigated by scanning electron microscopy after 3, 6, 24, and 48 hours of culture.


RESULTS
Dentin samples supported proliferation for both cell types, although growth kinetics were different. The laser dramatically affected the dentin profile, creating a rough and irregular surface. Cells grew easily on untreated dentin, but fewer cells were present on treated areas, often displaying long filopodes. hOBs showed poorer adhesion to treated dentin than PLFs.


CONCLUSIONS
The dentin disks provide a standardized and useful tool to study dentin surface modifications in vitro. PLFs behaved differently from hOBs on dentin, possibly because of their different affinity to this tissue and/or their differentiation state. The changes induced by the laser produced a less favorable environment for cell adhesion or growth, and treated dentin seemed to be more suitable for PLF adhesion compared to hOB adhesion.
Unit of Periodontology, University of Parma, Parma, Italy.
Carlo
C
Galli
Giovanni
G
Passeri
Antonio
A
Cacchioli
Giacomo
G
Gualini
Francesca
F
Ravanetti
Erida
E
Elezi
Guido M
GM
Macaluso
D000539:Alveolar Process / Q000166:cytology / Q000528:radiation effects; D000818:Animals; D002448:Cell Adhesion / Q000528:radiation effects; D002460:Cell Line; D049109:Cell Proliferation / Q000528:radiation effects; D048430:Cell Shape / Q000528:radiation effects; D004396:Coloring Agents; D003804:Dentin / Q000528:radiation effects* / Q000648:ultrastructure; D005347:Fibroblasts / Q000166:cytology / Q000528:radiation effects*; D006801:Humans; D053844:Lasers, Solid-State; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000166:cytology / Q000528:radiation effects*; D010513:Periodontal Ligament / Q000166:cytology / Q000528:radiation effects*; D011554:Pseudopodia / Q000528:radiation effects; D013778:Tetrazolium Salts; D013844:Thiazoles; D013997:Time Factors
D004396:Coloring Agents; D013778:Tetrazolium Salts; D013844:Thiazoles; C022616:thiazolyl blue