Why some get swollen gums after a single missed brushing while others are fine without toothpaste for life

If I skip brushing before bed, my gums swell the next day. Even from a single missed night. Yet there are many people on this planet who seem to pay little attention to hygiene, and even people who have never once used a chemical toothpaste in their lives. Are they really fine? Is one person clean and another dirty, or is there some other reason we have missed?

The first answer that comes to mind is the difference between people who brush well and those who do not, plus the idea that a good toothpaste makes you cleaner. But two things do not fit. First, even with the same lack of brushing, gums swell at different speeds in different people. Second, the real heart of it is not the toothpaste but something else. Look at what brushing actually removes, and why that reaction differs between people, and the answer appears.

Let us return to the first question. Is someone who lives without toothpaste dirty? Not necessarily. If they remove plaque effectively with a tool like miswak, the essence is achieved all the same. Someone who seems to mind hygiene less yet is fine may have a slow-reacting oral environment or a low-sugar diet. But this does not mean one need not brush. Let plaque build up long enough and anyone eventually runs into trouble. It is only that the limit differs from person to person. Conversely, someone like me whose gums swell after a single missed day is not excessive or weak, but simply has an environment that needs tending more often. In the end it is not a matter of better or worse. It is only a combination of different oral environments, different tools, and different diets.

Top: move the day to watch plaque build on an unbrushed tooth and the gums react (toggle fast/slow-reacting gums). Bottom: pick brush+paste, brush only, or miswak to see that different tools share the same essence of disrupting plaque.

The bacteria in the mouth constantly build a thin film on the surface of the teeth. It is called plaque. Leave this film without removing it, and the bacteria pile up at the gumline and irritate the gums. Stop all hygiene and, usually within ten days to three weeks, the gums redden, swell, and bleed. This is gingivitis. My gums swelling after a single missed day is the signal that this process is starting.

Here is the most important fact. The essence of brushing is not the chemicals in toothpaste but physically disrupting this film. The bristles scraping the film away is the core; toothpaste is closer to an aid that helps the job and adds flavor and fluoride. So as long as the film is disrupted in time, what the tool is comes second.

That is why, over the thousands of years without chemical toothpaste, people did the same job with other tools. A prime example is a chewing stick called miswak. The World Health Organization recommends miswak as an inexpensive and effective oral hygiene tool, and in several clinical trials its plaque removal matched or even bettered a toothbrush. On top of that, this stick contains natural antibacterial compounds that kill the bacteria behind gum disease. So a person who uses no toothpaste is not someone neglecting hygiene but someone achieving the same essence with a different tool. Not better or worse, but a difference of method.

Then why do gums react differently in different people? It has been confirmed by experiment that, stopping brushing under the same conditions, some people's gums swell quickly and others' slowly. What makes the difference is the makeup of the mouth's bacteria, the amount and content of saliva (saliva rinses away and neutralizes bacteria and acid), and diet. Eat a lot of sugar and the bacteria make more acid, burdening the gums. So my gums swelling after a single missed day is because my oral environment is on the fast-reacting side. Another person being fine for days is because their environment is on the slow-reacting side, or their saliva and diet differ.

So how much everyone else does cannot easily be my standard. The standard is the signal my own gums send. When they start to swell, whether blood shows, how they feel after brushing, these tell me the frequency I need. Whether the tool is a brush or a stick, whether there is toothpaste or not, what truly matters is one thing: not letting that film build up. Hygiene is less about brushing more often than others or using a better toothpaste, and more about managing that film in time, to suit my own oral environment. Someone's three times a day and someone else's single chewing stick can each be the right answer in their own mouth.

• Merck ManualGingivitis
• WHOOral health
• npj Biofilms and MicrobiomesDental plaque biofilm and experimental gingivitis
• BMC Complementary Medicine and TherapiesMiswak (Salvadora persica) and oral hygiene: clinical evidence