Antimicrobial Photodynamic Therapy (aPDT)

Fighting bacterial infections in the mouth

The prevalence of pathogenic bacteria is the main cause of bacterial infection in the mouth.

  • Periodontitis
  • Periimplantitis
  • Endodontics
  • Caries
  • Pulpitis
  • Delayed healing after surgical intervention
  • Failed endodontic treatment.

Destructive periodontitis & periimplantitis is caused by the formation of a highly pathogenic bacillus spectrum. Some important pathogenic marker bacilli of periodontitis:

  • Actinobacillus actinomycetemcomitans
  • Bacteroides forsythus
  • Porphyromonas gingivalis
  • Prevotella intermedia
  • Prevotella gingivalis
  • Treponema denticola.

While in endodontics the mechanical cleaning, the chemical desinfection and the obturation of the root canals have been increasingly made perfect, the persistence of bacteria is, particularly in the manifold ramifications, the tubuli and the apical delta, considered as THE main reason for failure. Some important marker bacilli of endodontics:

  • Enterococcus faecalis
  • Staphylococcus aureus
  • Beta-hämolysierende Streptokokken
  • Gramnegative aerobe Stäbchen
  • Schwarzpigmentierte Prevotellen
  • Porphyromonas, unpigmentierte Bacteroides and Fusiforme


A crucial factor in this context is that the bacteria are organised synergetically in highly complex biofilm structures. This means they are able

  • live together,
  • communicate,
  • look after themselves,
  • move about.

This makes it very difficult to access the bacteria integrated into the biofilm. In periodontitis/periimlantitis a pathogenic condition is caused by a shift in the bacterial spectrum with an increase in anaerobic bacteria.


In terms of conventional periodontitis treatment, various strategies are followed with the aim of impairing living conditions for the pathogenic bacteria and thus restoring the natural balance:

1. Mechanical tooth cleaning (closed/open),

  • Removes hard & soft deposits sub and supragingival ,
  • Has no effect on the bacterial spectrum.1
  • Can lead to hard tissue damage.2
  • The success with pockets > 6mm can be described as questionable.3
  • Is very painful under certain conditions.

1 "Lack of antimicrobial effect on periodontopathic bacteria by ultrasonic and sonic scalers in vitro."  J Clin Periodontol. 2000 Feb;27(2):116-9.; Schenk G, Flemmig TF, Lob S, Ruckdeschel G, Hickel R.
2 "Substance loss caused by scaling with different sonic scaler inserts--an in vitro study."  J Clin Periodontol. 2001 Jan;28(1):9-15.; Kocher T, Fanghanel J, Sawaf H, Litz R.
3 "Scaling and root planing with and without periodontal flap surgery";  J Clin Periodontol 1986 Mar;13(3):205-10; Caffesse RG; Sweeney PL; Smith BA

2. Rinsing solutions

  • Can inhibit surface bacteria.
  • Rinsed out of the sulcus very quickly.
  • They lead to detrimental effects on colour and taste.
  • Usage during gingivitis leads to increased plaque deposits.1

1 "The effects of antimicrobial mouthrinses on de novo plaque formation at sites with healthy and inflamed gingivae."  Department of Periodontology, Faculty of Odontology, Gothenburg University, Sweden.  J Clin Periodontol. 1996 Jan;23(1):7-11; Ramberg P, Furuichi Y, Volpe AR, Gaffar A, Lindhe J.

3. Antibiotics

  • Can significantly reduce bacteria in principle, but:
  • Under certain circumstances have very strong side effects.
  • The dosage and usage patterns are complex.
  • Use can lead to a build-up of resistance and the lack of compliance of the patient jeopardises success.1
  • The effect is not generally guaranteed.2

1 "Metronidazole in periodontitis (IV). The effect of patient compliance on treatment parameters." University of Michigan School of Dentistry, Ann Arbor 48109-1078. J Clin Periodontol. 1993 Feb;20(2):96-104; Loesche WJ, Grossman N, Giordano J.
2 "Systemic doxycycline administration in the treatment of periodontal infections (I). Effect on the subgingival microbiota." Department of Periodontology, Forsyth Dental Center, Boston, MA, USA. J Clin Periodontol. 1999 Dec;26(12):775-83; Feres M, Haffajee AD, Goncalves C, Allard KA, Som S, Smith C, Goodson JM, Socransky SS.

Read more:

Conventional therapies are thus limited in their usage as they either have no direct effect on the bacteria (tooth cleaning), are difficult to dose and apply (antibiotics and rinsing solutions) or are now unsuitable for general use due to accompanying negative effects. As a result of various research projects over the last 12 years, the basis for clinical application of a new form of therapy has been created:

The antimicrobial photodynamic therapy destroys as a matter of principle ALL bacteria, independent of the individual attributes of the bacteria (e.g. compatibility of oxygen, gram-stain attitude etc.) – also in the complex biofilm! Assumption for a long-term therapy success however is the beforehand conducted professional sub- and supragingival cleaning, the aPDT is adapted supplementary subsequent to cleaning.

Further information about "Photodynamic Therapy"?

Read more on the following pages: