Comparison of Microbial Changes in Early Redeveloping Biofilms on Natural Teeth and Denturesby F.R. Teles, R.P. Teles, A. Sachdeo, N.G. Uzel, X.Q. Song, G. Torresyap, M. Singh, A. Papas, A.D. Haffajee, S.S. Socransky

Journal of Periodontology




Comparison of Microbial Changes in Early Redeveloping Biofilms on Natural Teeth and Dentures

F.R. Teles,*† R.P. Teles,*† A. Sachdeo,‡ N.G. Uzel,§ X.Q. Song,* G. Torresyap,* M. Singh,i

A. Papas,i A.D. Haffajee,* and S.S. Socransky¶

Background: Surfaces and fluids can affect oral bacterial colonization. The aim of this study is to compare redeveloping biofilms on natural teeth and dentures.

Methods: Supragingival plaque samples were taken from 55 dentate individuals and the denture teeth of 62 edentulous individuals before and after professional cleaning. Also, samples from seven ‘‘teeth’’ (samples included dentures) in randomly selected quadrants were collected after 1, 2, 4, and 7 days of no oral hygiene. Samples were analyzed using checkerboard DNA-DNA hybridization. Counts and proportions of 41 bacterial taxa were determined at each time point, and significant differences were determined using the MannWhitney U test. Ecological succession was determined using a modified moving window analysis.

Results: Mean total DNA probe counts were similar precleaning but were higher in dentate individuals at all postcleaning visits (P <0.01). Precleaning edentate biofilms had higher counts and proportions of Streptococcus mitis, Streptococcus oralis, and Streptococcus mutans, whereas dentate individuals had higher proportions of Tannerella forsythia,

Selenomonas noxia, and Neisseria mucosa. By day 2, mean counts of all taxa were higher in natural teeth, and most remained higher at day 7 (P <0.01). Succession was more rapid and complex in dentate individuals. Both groups demonstrated increased proportions of S. mitis and S. oralis by day 1.N.mucosa,Veillonella parvula, andEikenella corrodens increased in both groups, but later in samples from edentate individuals.

Conclusions: ‘‘Mature’’ natural and denture teeth biofilms have similar total numbers of bacteria but different species proportions. Post-cleaning biofilm redevelopment is more rapid and more complex on natural teeth than on denture teeth. J Periodontol 2012;83:1139-1148.


Bacteria; biofilms; dental plaque; dentures; tooth.

T he formation of multispecies biofilms is influenced by three major factors: 1) the nature of the surface to which the biofilm adheres, 2) the composition of the potential colonizing species that will make up the biofilm, and 3) the bulk fluid(s) that bathe and sustain the biofilm community.1 This study examines the effect of two of the three factors: surface (tooth surface · denture surface) and bulk fluid (presence · absence of gingival crevicular fluid) on the sequence of species colonization in ‘‘dental’’ biofilms formed on natural teeth or on the ‘‘teeth’’ of full dentures.

This analysis was made possible by comparing the results of two studies that were conducted in the same laboratory using the same clinical and laboratory methods to examine biofilm regrowth after professional cleaning in the absence of home care procedures. 2,3 In one study,

Sachdeo et al.2 described the changes in numbers and proportions of 41 bacterial taxa in biofilms that formed on the denture teeth of 62 fully edentulous individuals. After an initial professional cleaning, individuals refrained from oral hygiene for 7 days. Total DNA probe counts returned to precleaning levels in approximately 4 days. Prominent species detected during the early recolonization period included Streptococcus mitis and

Streptococcus oralis. In a parallel study,

Uzel et al.3 reported the changes in mean microbial counts of the same 41 taxa * Department of Periodontology, The Forsyth Institute, Cambridge, MA. † Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine,

Boston, MA. ‡ Department of Prosthodontics, Tufts University School of Dental Medicine, Boston, MA. § Private practice, Bala Cynwyd, PA. i Division of Public Health Research and Oral Medicine, Tufts University School of Dental

Medicine. ¶ Deceased, previously, Department of Periodontology, The Forsyth Institute. doi: 10.1902/jop.2012.110506

J Periodontol • September 2012 1139 during 7 days of supra- and subgingival biofilm redevelopment after professional tooth cleaning in 38 periodontally healthy individuals, and 17 individuals with periodontitis. It was found that supragingival biofilm redevelopment was similar in the periodontally healthy individuals and individuals with periodontitis, and that the mean total

DNA probe counts reached precleaning levels by day 2. Prominent species that increased in total numbers during supragingival biofilm redevelopment included S. mitis, S. oralis, Capnocytophaga gingivalis, Eikenella corrodens, Veillonella parvula, and Neisseria mucosa. Mean species counts were significantly higher after 7 days of no oral hygiene than in the mature biofilm harvested prior to professional dental cleaning. In a follow-up study, Teles et al.4 described analytical methods to determine species succession during biofilm redevelopment.

They demonstrated more significant differences in species succession during supragingival biofilm development than subgingival biofilm redevelopment and found supragingival biofilm redevelopment to be similar in individuals who were periodontally healthy or had periodontitis. Species succession differed more profoundly between healthy individuals and those with periodontitis in subgingival samples.

The parallel conduct and identical methods used in the two parallel studies provided an unusual opportunity to examine the effect of surface and bulk fluid on early bacterial recolonization of ‘‘dental’’ surfaces. The purpose of the present investigation is to compare the changes in bacterial species numbers and proportions on natural teeth and denture teeth over a 7-day testperiod in theabsence oforal hygiene or denture cleaning. In addition, the nature of bacterial successionwasdetermined.Becauseas thesubgingivalbiofilm samples from the dentate individuals were clearly not analogous to the denture samples, data from subgingival samples were not included in this comparison.