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 419

Reliability of clinical and paraclinical parameters in different study populations during an experimental gingivitis study

Language: English

Dr. Katrin Lorenz, Dr. Gerlinde Bruhn, Prof. Dr. Michel Brecx, PD Dr. Lutz Netuschil, Prof. Dr.Thomas Hoffmann,
Poliklinik für Zahnerhaltung, Bereich Parodontologie, Technische Universität Dresden
PD Dr. Christian Heumann,
Institut für Statistik, Ludwig-Maximilians-Universität München

June 29, 30 and July 1, 2006
EuroPerio 5
Madrid, Spain


In designing a clinical controlled trial for the assessment of the efficacy of oral antiseptics, the selection of parameters and participants is a basic principle. The aim of this experimental gingivitis study was to determine whether correlations exist between different gingivitis parameters in distinctive populations.

Material and Methods

Study design: A 21-day experimental gingivitis study was performed. After a recruiting period the participants were randomly assigned to a mouthrinse group. During these 21 days no other oral hygiene measures than the rinsing were permitted.

Study populations: Three study populations were selected depending on the oral hygiene level of the participants at the recruiting visit.
Population A: 39 dental students with excellent oral hygiene (PII ≤ 0.5)
Population B: 38 participants from a local population with average oral hygiene (PII ≥ 1.0)
Population C: 77 participants of a mixed population regardless the oral hygiene level

Gingivitis parameters:
Gingival index (GI, Löe et al. 1967)
Modified gingival index (MGI, Lobene et al.1986)
Bleeding on probing (BOP, Ainamo and Bay 1975)
Gingival crevicular fluid (GCF)
Colony forming units (CFU)

Chlorhexidine dicluconate 0.20 %

Pearson correlation coefficient (p ≤ 0.05)


Statistically significant correlations were observed between GI and MGI in all groups and populations.
GI and BOP as well as MGI and BOP correlated in population C.
GI and GCF correlated only in population A after rinsing with CHX as did MGI and GCF.
No correlations were found between GI and CFU.

Population A Population B Population C
Placebo CHX 0.20 % Placebo CHX 0.20 % Placebo CHX 0.20 %
GI-MGI 0.961* 0.968* GI-MGI 0.928* 0.978* GI-MGI 0.944* 0.964*
GI-BOP 0.362 0.709* GI-BOP 0.515* 0.424 GI-BOP 0.444* 0.586*
GI-GCF 0.333 0.575* GI-GCF 0.514* 0.359 GI-GCF 0.388* 0.270
GI-CFU 0.216 0.213 GI-CFU -0.210 0.293 GI-CFU 0.063 0.199
MGI-BOP 0.236 0.700* MGI-BOP 0.522* 0.368 MGI-BOP 0.391* 0.561*
MGI-GCF 0.331 0.524* MGI-GCF 0.418 0.252 MGI-GCF 0.338* 0.259
Table 1: Pearson correlation coefficients: population A; n = 39;
*sign. p<0.05
Table 2: Pearson correlation coefficients: population B; n = 38;
*sign. p<0.05
Table 3: Pearson correlation coefficients: population C; n = 77;
*sign. p<0.05
Fig. 1: Correlation between GI and MGI; Placebo; r=0.961; p≤0.000; n=39 Fig. 3: Correlation between GI and MGI; Placebo; r=0.928; p≤0.000; n=38 Fig. 5: Correlation between GI and MGI; Placebo; r=0.944; p≤0.000; n=77
Fig. 2: Correlation between GI and MGI; CHX 0.20%; r=0.968; p≤0.000; n=39
Fig. 4: Correlation between GI and MGI; CHX 0.20%; r=0.978; p≤0.000; n=38
Fig. 6: Correlation between GI and MGI; CHX 0.20%; r=0.961; p≤0.000; n=77


GI and MGI are the most reliable parameters regardless of the composition of the study population. For the use of BOP during experimental gingivitis, however, a mixed population is preferred.

The study was supported by GABA International AG.


CHX = Chlorhexidine
GI = Gingival index
MGI = Modified gingival index
BOP = Bleeding on probing
GCF = Gingival crevicular fluid
CFU = Colony forming units

This Poster was submitted by Dr. Katrin Lorenz.

Correspondence address:
Dr. Katrin Lorenz
Technische Universität Dresden
Poliklinik für Zahnerhaltung, Bereich Parodontologie
Fetscherstraße 74
01307 Dresden
Phone: +49 351 4582712