A recent study published in the Polish Journal of Microbiology examined the effects of cola consumption on the pH levels and bacterial composition within the clear aligner-tooth microenvironment. The research suggests that cola can rapidly alter this environment, with differences observed based on whether clear aligners are removed before consumption.
Findings indicated that removing aligners before drinking cola resulted in a more pronounced pH drop and microbial imbalance at later time points compared to drinking with aligners in place.
Background
The human oral cavity hosts a diverse community of microorganisms. Clear aligners, which encase teeth, create a localized environment that can influence the oral microbiome and pH, potentially affecting enamel integrity. While carbonated beverages are known to contribute to dental caries, their specific interaction with the clear aligner interface, particularly regarding microbial dynamics, has been less extensively studied.
Methodology
The study involved 24 healthy female graduate students, with a mean age of 23.1 years, who were fitted with custom-made clear aligners. Participants were divided into three groups to evaluate different cola consumption methods:
- Group A (Control): Followed a normal diet without consuming cola.
- Group B: Removed aligners, rinsed their oral cavity with cola for 1 minute, and then replaced the aligners.
- Group C: Rinsed their oral cavity with cola for 1 minute while wearing their aligners.
Fluid and plaque samples were collected from the inner dental surfaces at specific intervals: 3 minutes (T0), 4 hours (T4), 8 hours (T8), 12 hours (T12), and 24 hours (T24) after the initial aligner wear or cola rinse. These samples were subsequently analyzed using high-throughput 16S rRNA gene sequencing to identify bacterial composition and diversity, and to profile operational taxonomic unit (OTU) abundance.
Key Findings
The study observed several changes in pH and microbial communities across the groups:
pH Changes
- Both Group B and Group C exhibited an immediate and significant decrease in pH at T0 compared to Group A.
- While pH levels showed a temporary recovery between T4 and T8, a more pronounced decline occurred at T12.
- The pH drop observed in Group B at T12 was significantly greater than that in Group C.
Microbial Diversity and Composition
- Microbial diversity, as measured by the Shannon alpha-diversity index, was lower in Groups B and C compared to Group A from 0 to 12 hours, with the difference becoming statistically significant at T12.
- Group B demonstrated the most significant microbial imbalance at T12.
- Beta diversity analysis indicated that Group B had a significantly more distinct microbial composition than the other groups at both 12 and 24 hours.
Specific Bacterial Shifts
- Fusobacteria: Group B showed a significantly higher relative abundance of the phylum Fusobacteria compared to Group C at 4 and 12 hours.
- Actinobacteria: Group B exhibited a significantly reduced abundance of Actinobacteria at 8 hours when compared to Group C.
- Bacteroidetes: Group B displayed lower levels of Bacteroidetes than the control group at 12 hours.
- Species-level (24 hours): At 24 hours, Neisseria subflava abundance was significantly lower in the control group than in the cola-consuming groups, while Haemophilus influenzae abundance was significantly higher in the control group.
Study Conclusions
The study concluded that cola consumption initiates rapid changes in the microbiome associated with clear aligners within a 24-hour period.
Drinking cola after removing aligners (Group B) resulted in a lower pH and a more pronounced microbial imbalance (dysbiosis) compared to drinking cola while wearing aligners (Group C).
The authors hypothesized that clear aligners might provide a physical "shielding effect" when worn, whereas removing them could allow cola residue to adhere more extensively to tooth enamel. This trapped residue, upon aligner replacement, may then intensify the effects of subsequent bacterial metabolism and acid production.