Local drug delivery for the treatment of periodontitis

Question 1

How can local drug delivery for periodontitis treatment be performed?

Answer 1

Three basic routes:

1. mouth rinses (solution, tooth paste, varnish)
2. local delivery systems
3. pocket irrigation

Question 2

Which of the 3 routes is most effective subgingivaly for local drug delivery for periodontitis?

Answer 2

Local delivery systems

Question 3

Which type of pharmaceutical agents have been used for treatment of periodontitis up to now?

Answer 3

• Antibiotics (Mainly tetracyclines and metronidazole)
• Antimicrobials/desinfectants (Chlorhexidine, cetylpyridinium chloride, oxidizing compounds, e.g. iodine, free oxygen, peroxides)

Question 4

Which pharmaceutical (galenic) formulations have been used to deliver these agents?

Answer 4

Solution, gel, toothpaste, varnish, strips and fibers with inert matrix (e.g. acrylic, ethylene vinyl acetate), bioresorbable matrices (e.g. cellulose acetate, hydroxypropylcellulose, denatured collagen), liposomes, nanoparticles, etc

Question 5

What is the theoretical half-time of a drug placed in a periodontal pocket and what is it based on?

Answer 5

Clearance of a drug placed into a periodontal pocket follows an exponential function. Clearance depends on the:

1. pocket (fluid) volume
2. GCF flow rate
3. time
4. substantivity of the drug

The theoretical half-time is about 1 minute when

• pocket (fluid) volume = 0.5 μl
• GCF flow rate = 20 μl/h
• substantivity of the drug = 0

Question 6

What kind of devices were used for drug delivery in the periodontal pockets?

Answer 6

1. Permeable hollow cellulose acetate fibers, 200 μm thick, filled with a 20% tetracycline-HCI solution.
2. a monolithic design (drug crystals interspersed within an inert matrix) such as acrylic strips or extruded ethylene vinyl acetate fibers with 25% tetracycline-HCI.
3. bioresorbable matrices (chlorhexidine in cellulose acetate, hydroxypropylcellulose or collagen matrices)

Question 7

What strategic elements for the rationale use of local drug delivery devices were drawn from the clinical studies?

Answer 7

• Effective local delivery devices have the potential to dramatically change the microbial profile of treated periodontal pockets. Recolonization, however, is a critical phenomenon that may undermine clinical benefit.
• Bacteria present in other areas of the mouth are the major source of recolenization and need to be addressed by improved oral hygiene measures, treatment of the whole dentition, and perhaps - antimicrobial mouth rinsing.
• Local delivery devices are not a promising treatment for subjects who are unable or unwilling to achieve improved (optimal) oral hygiene levels

Question 8

What is the efficacy of pocket irrigation with antimicrobials and what does it depend on?

Answer 8

• No evidence of an adjunctive benefit from the application of local irrigants during or immediately after mechanical debridement.
• This finding is consistent with what can be expected based on local pharmacokinetic parameters: irrigating solutions are probably rapidly cleared by GCF flow

Question 9

What are the indications for local drug delivery in periodontitis treatment?

Answer 9

• Special local conditions: (Deep pockets, before surgery, “esthetic zone”)
• Only as a temporary measure: Relapse of the disease implies existence of unfavorable conditions
• Special patient groups: (High-risk patients)-No good evidence

Question 10

Is full mouth disinfection beneficial and how?

Answer 10

• A modest benefit for full mouth disinfection. The superiority of the intervention had not been conclusively demonstrated.
• Current recommendations support its use as equal and equivalent to other established effective treatment modalities