Surface pre-conditioning with bioactive glass air-abrasion can enhance enamel white spot lesion remineralization.
OBJECTIVE
To evaluate the effect of pre-conditioning enamel white spot lesion (WSL) surfaces using bioactive glass (BAG) air-abrasion prior to remineralization therapy.


METHODS
Ninety human enamel samples with artificial WSLs were assigned to three WSL surface pre-conditioning groups (n=30): (a) air-abrasion with BAG-polyacrylic acid (PAA-BAG) powder, (b) acid-etching using 37% phosphoric acid gel (positive control) and (c) unconditioned (negative control). Each group was further divided into three subgroups according to the following remineralization therapy (n=10): (I) BAG paste (36 wt.% BAG), (II) BAG slurry (100 wt.% BAG) and (III) de-ionized water (negative control). The average surface roughness and the lesion step height compared to intra-specimen sound enamel reference points were analyzed using non-contact profilometry. Optical changes within the lesion subsurface compared to baseline scans were assessed using optical coherence tomography (OCT). Knoop microhardness evaluated the WSLs' mechanical properties. Raman micro-spectroscopy measured the v-(CO3)(2-)/v1-(PO4)(3-) ratio. Structural changes in the lesion were observed using confocal laser scanning microscopy (CLSM) and scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX). All comparisons were considered statistically significant if p<0.05.


RESULTS
PAA-BAG air-abrasion removed 5.1 ± 0.6 μm from the lesion surface, increasing the WSL surface roughness. Pre-conditioning WSL surfaces with PAA-BAG air-abrasion reduced subsurface light scattering, increased the Knoop microhardness and the mineral content of the remineralized lesions (p<0.05). SEM-EDX revealed mineral depositions covering the lesion surface. BAG slurry resulted in a superior remineralization outcome, when compared to BAG paste.


CONCLUSIONS
Pre-conditioning WSL surfaces with PAA-BAG air-abrasion modified the lesion surface physically and enhanced remineralization using BAG 45S5 therapy.
Tissue Engineering & Biophotonics Research Group, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK; Restorative Dentistry, Dental Institute, Damascus University, Syria.
Hussam
H
Milly
Tissue Engineering & Biophotonics Research Group, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK.
Frederic
F
Festy
King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK.
Manoharan
M
Andiappan
Tissue Engineering & Biophotonics Research Group, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK; Conservative & MI Dentistry, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK.
Timothy F
TF
Watson
Tissue Engineering & Biophotonics Research Group, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK.
Ian
I
Thompson
Tissue Engineering & Biophotonics Research Group, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK; Conservative & MI Dentistry, King's College London Dental Institute at Guy's Hospital, King's Health Partners, London, UK. Electronic address: avijit.banerjee@kcl.ac.uk.
Avijit
A
Banerjee
D000134:Acid Etching, Dental; D000180:Acrylic Resins / Q000737:chemistry; D020906:Air Abrasion, Dental; D002516:Ceramics; D003743:Dental Enamel / Q000473:pathology*; D005898:Glass; D006244:Hardness; D006801:Humans; D066298:In Vitro Techniques; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008963:Molar; D013052:Spectrometry, X-Ray Emission; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D041623:Tomography, Optical Coherence; D014089:Tooth Remineralization / Q000379:methods*
D000180:Acrylic Resins; C425330:bioactive glass 45S5; C006903:carbopol 940
Air-abrasion; Bioactive glass (BAG); Enamel white spot lesion; OCT; Polyacrylic acid (PAA); Remineralization