Chewing Gum Containing Magnolia Extract Inhibits Human Dental Plaque Biofilm

Objectives: Natural antimicrobial compounds from magnolia bark extract (MBE, Magnolia officinalis) have been shown to inhibit growth and viability of oral pathogens. Compressed mints and chewing gum containing MBE were effective against human oral bacteria responsible for halitosis. We hypothesize that chewing gum containing MBE delivers antimicrobial compounds to the oral cavity, and inhibit metabolic activity of human dental plaque biofilm. Objective: To evaluate the effect of chewing an MBE-containing gum on acid production and regrowth of human supragingival plaque biofilm. A placebo gum without MBE and a non-flavored gum base were included as controls.

Methods: Nine adults participated in this randomized controlled cross-over study. Overnight fasting supragingival plaque from buccal and lingual surfaces in the left maxillary and mandibular quadrants of a participant was collected using a sterile swab (Baseline untreated plaque). The participants then chewed one of the three gums for 10 min [chewing gum containing MBE (MBE gum), gum without MBE (Placebo gum), or non-flavored gum base (GB)], and their right maxillary and mandibular quadrants was sampled 20 min after chewing. All plaque samples were dislodged from swabs, re-suspended, and assessed for regrowth and glycolysis after 2 and 4hr incubation at 37°C (PGRM, White et al., 1995).
Results: Chewing a gum containing MBE for 10 min reduced short-term regrowth (4 hr, averaging 21%) of human supragingival plaque biofilm. Although the MBE gum did not show statistically significant inhibition of acid production likely due to the small number of participants, a clear trend of inhibition was noted when compared to the placebo gum or the GB. Chewing the placebo gum or GB did not inhibit subsequent regrowth or glycolysis of plaque biofilm.
Conclusions: In addition to its breath-freshening effect, appropriately formulated chewing gum containing MBE may serve as an effective oral delivery system of natural antimicrobials for short-term plaque control.