International Poster Journal of Dentistry and Oral Medicine



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Int Poster J Dent Oral Med 10 (2008), No. 3     15. Sep. 2008

Int Poster J Dent Oral Med 2008, Vol 10 No 03, Poster 413

Vitality of dental biofilms in relation to plaque formation

Language: English

Authors: Prof. Dr. Thomas Hoffmann, Dr. Pia Rüdiger, PD Dr. Lutz Netuschil,
Poliklinik für Zahnerhaltung, Bereich Parodontologie, Technische Universität Dresden

March 21-24, 2007
IADR/AADR/CADR 85th General Session and Exhibition
New Orleans, Louisiana, USA


Several investigations demonstrated a difference in the formation of plaque between different individuals enabling the clinician to distinct between "slow" and "heavy" plaque formers.


Our aim was to compare the percentage of vital micro-organisms in slow and heavy plaque formers, in different areas of the mouth, and at different teeth.

Material and Methods

Participants: Fifty participants (38 female, 12 male) including students of the dental school and participants from the local community in Dresden, Germany.

Study design:
After a professional tooth cleaning was performed, the plaque which formed after 8 h, 24 h, and 72 h of undisturbed plaque accumulation was assessed quantitatively and qualitatively.
Plaque index (PlI; Silness and Löe 1964).
Plaque formation rate index (PFRI; Axelsson 1990)
Vital fluorescence microscopy (VF; Netuschil et al. 1989).
Participants were assigned to "heavy" or "light" plaque formers according to either PFRI or PlI.
U-test (p < 0.05).

Figure 1: Flow chart


A statistically significant increase of plaque vitality with duration of plaque formation was observed. At all investigation time points a higher amount of vital microorganisms was registered in "heavy" plaque formers when compared to "slow" plaque formers (p<0.01).
No differences in plaque vitality could be found between upper and lower jaw and between different quadrants of the mouth. The biofilm of incisor teeth exhibited statistically significant less vital micro-organisms as that of molar teeth (p<0.002).

Figure 2: Vitality of plaque bacteria at 8 h, 24 h, and 72 h of undisturbed plaque growth Figure 3: Plaque vitality at "light" and "heavy" plaque formers by PFRI
Figure 4: Plaque vitality at molars and incisors
Figure 5: Plaque vitality at "light" and "heavy" plaque formers by PFRI


The evaluation of plaque formation rate could be helpful for preventive strategies of caries and of periodontal diseases. Persons as well as teeth exhibiting a heavy plaque formation show a statistically significant higher amount of vital micro-organisms and should be therefore included in high risk oriented prevention and recall systems.


PlI = Plaque index
PFRI = Plaque formation rate index
VF = Vital fluorescence

This Poster was submitted by Prof. Dr. Thomas Hoffmann.

Correspondence address:
Prof. Dr. Thomas Hoffmann
Medizinische Fakultät der Technischen Universität Dresden
Poliklinik für Zahnerhaltung, Bereich Parodontologie
Fetscherstraße 74
01307 Dresden
Phone: +49 351 4582712