Plant Extracts Decrease Dental Plaque Formation

plaque formation

Traditional medicinal plants extracts exhibiting anti-bacterial and anti-adherence activities play a significant role in the proper maintenance of oral health. A new clinical trial study revealed that the plant product combination of green tea (Gt) and Salvadora persica (Sp) extract taken as mouthwash twice a day decreases plaque formation on the teeth surface through antimicrobial and anti-adherence activity for a 24 hour period.


Dental plaque, the bioaccumulation of bacterial deposits on the hard or soft oral tissues of teeth caused by oral diseases, has a significant health concern globally. Following proper maintenance strategies for oral hygiene reduces the problem of plaque formation.  Generally, dental plaque, which is usually removed mechanically by toothbrush usage, is found to be associated with a spectrum of dental diseases related to inflammation or infection of the gums (gingivitis/periodontitis). Hence, chemical treatment such as Chlorhexidine (CHX, oral rinse) has been adopted for treating plaque but some complications related to staining on teeth, taste function and hardening of dental plaque calculus formation still exist. In order to overcome these problems, traditional medicinal plant extracts such as

In order to overcome these problems, traditional medicinal plant extracts such as Salvadora persica L(Sp) has been employed in treating dental plaque, as they significantly reduce primary plaque microbial colonizers (Streptococcus mitis, Streptococcus sanguinis, Streptococcus oralis and Streptococcus salivarius) with their anti-bacterial activity. In addition, green tea (Gt) extracts have also been employed in bacterial dental plaque as they are reported to have enhanced periodontal therapeutic effects. Studies have reported that a combination of Gt (0.25 mg/ml) and Sp (7.82 mg/ml) extracts exhibited significant antibacterial and anti-adherence effects against dental plaque colonizers. Therefore, a randomized clinical trial study was conducted by Baharuddin and his research team at the University of Malaya, Malaysia. The study analyzed the plant extract combination’s (Gt and Sp) ability to reduce plaque biofilms when compared with a control (0.12% CHX), over a 24 hour period. The study results were published in BMC Complementary and Alternative Medicine, 2016.

Researchers carried out a double-blinded, randomized crossover trial study on 24 h plaque re-growth in order to establish the plant extract’s impact on dental plaque control. The subjects (n = 14) had good health, with more than 20 teeth, with age ranging from 25-40 years and were randomly subjected to three different interventions: control (0.12% CHX), test formulation (combination of Gt:0.25 mg/ml) + Sp:7.82 mg/ml leaf extracts) and distilled water (placebo) mouthwashes for 24 h duration. On the day of the clinical trial, the subjects received polishing and were instructed to rinse with 15 ml of the mouthwash they were randomly assigned to twice a day without following any specific oral hygiene measures. After 24 h, the dental plaque yield was recorded using the modified Quigley-Hein plaque index (PI) and participants followed a 6-day washout period with standard oral hygiene measures. The participants then conducted this same protocol using the other two types of mouthwash. The results of the study indicated the mean PI of the test formulation group was showing significantly lower scores (score of 0.93) when compared with placebo (1.44) and control (1.32) groups. This anti-plaque effect of the test formulation is mainly the result of both antibacterial and anti-adherence activities, preventing the formation of dental plaques. However, the small size of participants in the study could have resulted in no significant difference between the mean PI of the CHX and placebo scores.

In short, a combination of Gt and Sp leaf extracts taken twice a day as mouthwash significantly decreased plaque formation better than CHX after 24 h re-growth; this indicates the extracts’ anti-bacterial and anti-adherence activity. Future clinical research allowing for more duration of use should be considered for confirming the activity of plant extracts in dental plaques and also for understanding the activity of the Gt and Sp extract combination at lower concentrations on gingival tissue.


Written By: Manche Santoshi, PhD