In situ substrate-formed biofilms using IDODS mimic supragingival tooth-formed biofilms

Abstract

This study aimed to compare the bacterial viability and diversity of a substrate-formed biofilm (SF-biofilm) in situ to a supragingival tooth-formed biofilm (TF-biofilm) in the same group of individuals. The impact of the device/disc position and toothbrushing during the formation of SF-biofilm was also assessed. Two tests were run. In test 1, 15 volunteers wore two hemi-splints carrying six discs of human enamel, glass, and hydroxyapatite for 2 days, and were instructed to not perform any oral hygiene measure. Biofilm samples were collected from the substrates and the contralateral tooth and were analysed using CLSM. In five volunteers, half of the biofilm present on the discs and their contralateral teeth were scraped and analysed using 16S pyrosequencing. In test 2, the microscopic analysis was repeated only on the SF-biofilm samples, and the volunteers were allowed to brush their teeth. Multivariate analyses revealed that the donors had a significant effect on the composition of the biofilm, confirming its subject-dependent character. The bacterial composition of the SF-biofilm was similar to the TF-biofilm, with significant differential abundance detected in very few taxa of low abundance. The toothbrushing during the formation of SF-biofilm was the only factor that conditioned the thickness or bacterial viability.

Intraoral appliances for in situ oral biofilm growth: a systematic review

“…The device consists of a soft flexible inner splint and a more rigid outer splint carrying the glass substrate in between the two splints. Most workers placed the appliance in one jaw only, either the upper jaw [5,13,14,[21][22][23][24][25][30][31][32][33] or the lower jaw [19,27,29,[30][31][32][33][34]37]. However, Auschill et al [20], Langfeldt et al [26] and Tomas et al [34] placed the appliance in both jaws to investigate the differential characteristics of the biofilm growing in both the upper and lower jaws.…”

“…Different solid substrates with varying properties have also been used in these studies for instance human enamel in the Leeds in situ device [5,13], human enamel-dentine slab [30], bovine enamel/dentine [19,[22][23][24]31], polished glass [14,20,21,25,29,[34][35][36][37][38][39][40], hydroxyapatite discs [27,[32][33][34], or membrane filters [26]. Although the roughness of the surface of the substrate and its free energy are considered important factors for in vivo growth of the biofilm, Auschill et al [20] and Netuschill et al [41] found no major differences in the thickness of 48-h biofilm grown on enamel or glass discs.…”

“…The number of substrates used in each experiment also varies substantially from 2 [5,13,19] to 15 [20]. Most workers used six substrates on the buccal side of the appliance, placing three substrates on each side of the jaw [14,[21][22][23][24][25]27,[29][30][31]33,34,37,39]. The latter workers employed either cylindrical or cuboidal form substrates.…”

“…The latter workers employed either cylindrical or cuboidal form substrates. The size of the substrate was variable; as for the cylindrical discs the diameter varied from 3 mm [20][21][22]25] to 7 mm [34], while the height varied from 1 mm [14,35,36,38,40] to 4 mm [30]. Interestingly, Wood et al [13] observed significant variations in the thickness of the biofilms generated over the 4-day period between each disc, depending on the substrate architecture.…”

“…Auschill et al [20] however, demonstrated that the mean thickness of 48-hr biofilm ranged from 14 to 150 µm and was not affected by the location of the removable appliance in the oral cavity (maxillary buccal region versus mandibular buccal region) or by the position of the substrate (distal versus mesial; right versus left). In addition, Tomas et al [34] reported the position of the intraoral device and substrate did not affect the thickness and vitality of the biofilm formed on the substrate.…”