Original study - ZZI 01/2009

Essential oils: antimicrobial effects and potential treatment options in dental implantology

P.H. Warnke1,2, R. Podschun3, J. Wiltfang1, I.N.G. Springer1, E. Behrens1, S.T. Becker1

Due to the steadily increasing numbers of dental implants placed, the number of peri-implant infections is also growing. To date, there is no standard and generally accepted regimen for treating peri-implant infections. The search for alternative treatment options is ongoing. This pilot study focuses on the antimicrobial effects of essential oils as their antimicrobial and anti-inflammatory effects have recently been highlighted in literature. The results may offer potential treatment options for peri-implant infections based on natural essential oils. Eucalyptus, tea tree, white thyme, lemon, lemongrass, clove bud oil and oil combinations were tested in the agar diffusion test against clinically relevant strains and multi-resistant nosocomial isolates. Ethanol, povidone iodine, chlorhexidine as well as olive and paraffin oil served as controls. The essential oils tested showed clear antimicrobial effects against staphylococci, streptococci and candida. In particular, the absolute impact on multi-resistant strains such as MRSA and Candida krusei should be stressed. The anti-inflammatory properties of essential oils may be advantageous in dental implantology compared to classic antiseptics. Essential oils can be produced naturally and cost-effectively. If the suspected antimicrobial effects can be confirmed against the dominant strains in peri-implant infections, essential oils may offer an alternative in the local treatment of these infections.

 

Keywords: Essential oils, antimicrobial, peri-implant infection, multi-resistant strains, MRSA, antiseptics

Introduction

The insertion of dental implants is a routine procedure in dentistry nowadays. Treatment with dental implants allows outstanding aesthetic reconstruction with optimal masticatory function following tooth loss. Modern dental implants usually have bioinert titanium surfaces and the healing rates are over 97 % [25].

However, peri-implant infections, similar to periodontal pocket infections with natural teeth, are a potential problem. Peri-implant infections involve the tissue surrounding the implant. A distinction is made between “peri-implant mucositis“ and “peri-implantitis“. The former consists of reversible inflammation of the soft tissue. When chronic inflammation progresses with marked submarginal accumulation of plaque, peri-implantitis can develop; this is characterized by irreversible progressive bone loss in addition to the soft tissue infection. The development of peri-implant infection does not necessarily mean that implant loss is inevitable if provided treatment is commenced in time. Osseointegrated oral implants differ from titanium joint prostheses in orthopedic surgery. If the latter become infected, they must often be removed despite broad-spectrum antibiotic therapy for several weeks [19].

Different regimens for treating peri-implant infections have been presented at specialist conferences, some of them controversial, so that to date there is no uniform, standardized and generally accepted treatment regimen. Whereas non-specific broad-spectrum antibiotic therapy (e. g. tetracycline and metronidazole) was employed for several weeks up to the end of the 1990s, as in the case of infected orthopedic implants, a regimen based on the treatment of natural dental pocket infections and involving local insertion of anti-inflammatory medications following curetting plus disinfectant oral rinses (e. g. chlorhexidine) daily for several weeks is now accepted [21]. Laser photodynamic or photothermal elimination of the bacteria flora appears promising [22] but is not available to every clinician, so it may be too specialized to be considered a standard treatment. Peri-implant colonization with pathogenic micro-organisms is usually the cause of the infection, but this can be encouraged by other causal factors, e. g. a lack of keratinized gingiva. In these cases, antiseptic treatment on its own is insufficient and complex treatment with several sessions to eliminate all the promoting factors becomes necessary.

Treatment failures due to poor patient compliance are not rare and are an underestimated problem. The best treatment will not be effective if the patient does not cooperate. This often results in the infection becoming chronic. The clinician often switches to local and systemic antibiotic therapy in order to preserve the valuable prosthetic implant constructions. The high costs of a prosthetic restoration, which must be met privately, can be a source of tension between dentist and patient if loss appears imminent. The patient often looks for mistakes in the quality of the work (“it cost a lot so it has to last a long time“). Thus, the patient’s cleaning problem becomes a problem for the dentist and possibly for his reputation, which leads to early initiation of aggressive antibiotic therapy. This produces an increased risk of selection of antibiotic-resistant micro-organisms, which may even cause life-threatening abscesses [3]. In orthopaedic surgery, the long-term use of antibiotics has already led to a substantial increase in antibiotic resistant pathogens associated with artificial joint implant infections [1].

Accordingly, there is great interest in developing new regimens for the treatment of peri-implant infections. These should

1. effectively combat microbiological colonization of the implant with pathological flora,

2. limit the development of antibiotic-resistant micro-organisms,

3. prevent selection of secondary pathological flora (e. g. secondary candida infections after antibiotic treatment),

4. have anti-inflammatory characteristics in order to reduce destructive endogenous cytokines and enzymes as a result of inflammation,

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