Efficacy of an aluminium triformate mouthrinse during the maintenance phase in periodontal patients: a pilot double blind randomized placebo-controlled clinical trial

The link between oral health and general health is becoming generally accepted. Prevention of oral inflammatory diseases is considered to be a key element of good oral and systemic health [1]. Tools and chemical compounds in addition to mechanical plaque control may be helpful to support oral health. Additional chemical plaque control as part of domestic oral hygiene has always been playing an important role in the treatment of gingival inflammation [2, 3].

Patients with periodontitis need to be enrolled in a periodontal treatment protocol. During the initial visit, the patient’s medical and dental history is evaluated and clinical examinations and radiographic analyses are performed. The patients are being informed that periodontitis is an irreversible disease and that progress can be arrested by proper treatment. Periodontal treatment includes non-surgical and surgical procedures and domestic oral hygiene regimes. The maintenance phase after periodontal treatment is as important as the treatment itself and plays a decisive role whether the long-term outcome is successful or not [4]. Continuous domestic oral hygiene is indispensable to reach this aim and suitable antiseptics may help.

Chlorhexidine digluconate (CHX) is currently considered to be the most effective antiseptic mouthrinse due to its high substantivity and strong anti-bacterial effects and has been used in dentistry for many decades as liquid or gel [5]. Numerous studies have confirmed its efficacy in inhibition of plaque formation and reduction of gingival inflammation [6, 7]. CHX-containing mouthrinses have a significant antibacterial effect up to 7 h after its application [8]. Its efficacy is similar in mouthrinses with and without alcohol [9]. However, CHX has side effects such as reversible dysgeusia, black hairy tongue and tooth discolorations [5, 10‐12] and is therefore not suitable for daily use in long-term periodontal maintenance. As a consequence, the search for effective alternatives without side effects continues.

Novel rinsing solutions should be tested for their application in periodontal maintenance for efficacy and side effects. Aluminium triformate (ATF), an aluminium salt, has been used for several decades in Europe to control “bleeding gums” and is considered to be safe for daily use. Other compounds of aluminium salts (aluminium-containing mouthrinses) have shown a reducing effect on bacterial growth and plaque formation [13, 14]. Application of alum (in combination with salt and vinegar) for mouth rinsing was advocated by Hippocrates approx. 2400 years ago [15]. Aluminium and other similar metals (polyvalent cations) are widely used in dental products [14]. ATF is available since 1967, but besides some clinical trials in the 80ies of last century that did not meet todays’ standards of good clinical practice, studies have not been performed so far to test its efficacy in the periodontal maintenance phase. ATF is likely anti-inflammatory due to its astringent characteristics, but data are not available for its effects on gingival inflammation and plaque formation. ATF creates a protective surface of denaturated keratins and other proteins as a colloidal layer through ionic bonds with proteins of the gingiva preventing penetration of bacterial compounds such as endotoxins into the underlying connective tissue.

The aim of this clinical short-term pilot study was to analyze the effects of ATF as active component in a commercially-available mouthrinse (Cional®; Kreussler & Co. GmbH, Wiesbaden, Germany) as an adjunct to mechanical oral hygiene in the maintenance phase of periodontal patients. The primary hypothesis was that the use of ATF leads to a stronger reduction of gingival inflammation than placebo. The secondary hypothesis was that the use of ATF reduces plaque formation and does not have significant side effects whereas the compliance of patients is good.

The present double blind placebo-controlled pilot trial is the first in vivo study that evaluates the efficacy of an ATF-containing mouthrinse used by periodontal patients in the maintenance phase. Fourty patients were enrolled and have completed this study. The primary hypothesis of this study was that ATF reduces the MSBI more than placebo without significant side effects has been confirmed.

After a period of 7 days, there was a notable reduction in gingival bleeding in both groups. The comparison between the two groups showed a significantly higher reduction in gingival bleeding as assessed by MSBI in the ATF group. This is consistent with patients’ subjective experience in the ATF group of reduced sulcus bleeding after rinsing. PI and API were not affected during this short-term application of an ATF-containing mouthrinse. It should be noted that the current rinsing period is relatively short, long-term effects of the rinsing with ATF need to be investigated. This pilot study was performed to demonstrate whether MSBI, PI and API were affected by an ATF-containing mouthrinse without side effects and whether the compliance of the patients included in the study was good.

This study was a pilot study and therefore not necessarily powered to detect significant differences between treatments. In this study, the estimated probability that ATF leads to a stronger decrease in MSBI (P(ΔMSBI_ATF < ΔMSBI_Placebo)) was 0.3125. When calculating sample size and power under the assumption that P(ΔMSBI_ATF < ΔMSBI_Placebo) = 0.3125 and significance level α = 0.05, 38 patients per group are needed to demonstrate this effect with 80 % power and 50 patients are needed to demonstrate this effect with 90 % power. With 20 patients per group, the calculated power is 53 %. Hence, further studies should include at least 100 patients in order to demonstrate efficacy of ATF.

The improvement of the MSBI values in the placebo group can be explained by the Hawthorne effect [18]. This phenomenon is considered to be based on increased attention, e.g. due to the participation in a clinical trial and the consciousness of being evaluated, leading to an improvement of productivity, or, in this case, a reduction in MSBI in the placebo group because of an improved oral hygiene during the study. However, a similar Hawthorne effect must be present in the ATF group, too. Because both patients and investigator were masked with respect to treatment, it is unlikely, that this effect differs between groups. The reduction in MSBI was significantly stronger in the ATF group than in the placebo group, which points at a true effect of ATF on MSBI.

Lang et al. [19] demonstrated the correlation between the amount of gingival bleeding and tooth survival in patients during periodontal maintenance. It was shown that periodontal patients with bleeding ≥16 % on probing had a higher risk of losing attachment than patients with <16 % bleeding on probing. After 4 consecutive maintenance appointments, patients with no bleeding on probing had a 20-fold lower risk of attachment loss than patients with bleeding on probing at the 4 maintenance appointments. These data indicate the importance of oral hygiene and control of gingival bleeding during the maintenance phase.

Ramberg et al. [20] showed a correlation between gingival inflammation and de novo plaque formation. Reduced gingival inflammation lowers the amount of crevicular fluid that contains proteins, which are metabolized by plaque microorganisms. As the quantity of crevicular fluid correlates with the grade of gingiva inflammation, a reduction of sulcus irritation decreases the inflammation and therefore prevents de novo plaque formation. Furthermore, Van der Velden [21] stated that gingival fluid is the major cause of de novo plaque formation. However, neither ATF rinse nor placebo rinse had any effect on the amount of dental plaque during the short experimental period of 7 days in our study. Putt et al. [14] showed a significant reduction in the amount of plaque after 2 and 4 weeks of rinsing and thus, it may well be that longer rinsing periods show effects on plaque levels as well.

With respect to the patients’ evaluation reports, ATF mouthrinse seems to be safe and not causing harmful side effects. Almost all patients in the ATF group reported the rough sensation of gingiva and teeth surface accompanied with a metallic taste. These sensations can be clearly explained by the astringent properties of aluminium solutions [22]. However, these sensations disappeared after a few minutes and not one patient indicated a desire to stop the rinsing, thus it is concluded that compliance of the patients included in the study is good.

The fast reduction in gingival bleeding may be useful as a pre-surgical measure in patients with inflamed gingiva. For protocols in which authors propose immediate periodontal surgery (without initial therapy) in patients with advanced periodontitis [23], it can be recommended that patients rinse with ATF during one week before surgery; the styptic effect of ATF may well be beneficial, but this application in untreated periodontitis patients is not yet tested and needs further investigation. ATF rinse may also be beneficial for patients with fixed orthodontic appliances during an acute period of gingival inflammation that are at risk for temporary periodontal destructive processes [24].

ATF mouthrinse solution appears to be a promising adjunct to mechanical tools in the periodontal maintenance phase in our short-term pilot clinical trial. A long-term trial with a larger number of participants is needed to confirm our findings. The current study shows that the ATF rinse solution is well accepted by patients and does not have major and long-lasting side effects.