Antimicrobial penetration in a dual-species oral biofilm after noncontact brushing: an in vitro study

• Published in: Clinical oral investigations Vol. 18; no. 4; pp. 1103 - 1109
• Main Authors: He, Y., Peterson, B. W., Ren, Y., van der Mei, H. C., Busscher, H. J.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-05-2014; Springer Nature B.V
• Subjects: Anti-Infective Agents - administration & dosage; Biofilms; Dentistry; In Vitro Techniques; Medicine; Original Article; Toothbrushing; Viscoelasticity; Antimicrobial penetration; Dual strains biofilm; Mouthrinse; Noncontact brushing
• ISSN: 1432-6981; 1436-3771
• DOI: 10.1007/s00784-013-1097-x

Objectives
Oral biofilm is inevitably left behind, even after powered brushing. As a special feature, powered brushing removes biofilm in a noncontact mode. When the brushing distance becomes too large, biofilm is left behind. We hypothesize that biofilm left behind after brushing has different viscoelastic properties than before brushing, impacting antimicrobial penetration.
Materials and methods
In vitro grown dual-species biofilms were subjected to 20 % mechanical deformation before and after powered brushing at 4-mm brushing distance. Biofilm thickness and stress relaxation were measured for unbrushed and brushed biofilms. Stress relaxation was analyzed with a three-element Maxwell model. Antimicrobial penetration from five mouthrinses was microscopically evaluated for unbrushed and brushed biofilms.
Results
Thicknesses of unbrushed and brushed biofilms were similar. Brushing decreased the prevalence of fast and increased the prevalence of slow relaxation elements, which was accompanied by deeper penetration of chlorhexidine and cetylpyridinium chloride. Penetration of antimicrobials from other mouthrinses was relatively low in unbrushed and brushed biofilms.
Conclusions
This confirmation of our hypothesis points to an additional advantage of powered toothbrushing in a noncontact mode, changing the viscoelastic properties of biofilm in a direction that increases antimicrobial penetration of chlorhexidine and cetylpyridinium.
Clinical relevance
The biofilm left behind after noncontact powered toothbrushing may have less recalcitrance toward penetration of chlorhexidine and cetylpyridinium chloride than prior to brushing.