Dentist Reveals Why Flossing Causes Bleeding Gums: Don't Poke Directly Into Tooth Gaps
Improper interdental brush technique—inserting directly into tooth gaps instead of angling alongside teeth—causes bleeding gums, warns a Taiwan dentist who recommends stopping if you feel resistance and switching to floss for tight spaces.
Many people use interdental brushes to clean between their teeth, but improper technique can damage the gums. Dentists warn against inserting the brush straight into tooth gaps; instead, position it alongside the tooth and gently angle it into the space with a light touch. If you feel resistance, pain, or stiffness, don't force it further, as this can cause bleeding, soreness, or inflammation.
Dr. Chang Tian-hao, a dentist at Taiwan's National University Hospital and an endodontics specialist, notes that clinically, many patients injure their gums while trying to clean between their teeth properly—often by inserting the brush directly into the gap from the front, causing the wire core to strike the gum directly, resulting in pain and bleeding. The correct technique involves angling the brush head slightly and sliding it gently along the side of the tooth into the gap, not poking straight at the gum. If you encounter resistance, clear counter-pressure, or pain, it indicates improper angle, incorrect brush size, or that the gap isn't suitable for interdental brushing.
Dr. Chang identified four main reasons why interdental brushes don't fit properly:
1. Gaps too tight: Some people have almost no space between teeth and should use floss instead of forcing an interdental brush. 2. Crowns or bridges: If artificial tooth margins are close to the gum, the brush may not fit, and forcing it can cause gum recession. 3. Wrong angle: Use the brush along the side of the tooth, not jabbed directly toward the gum. 4. Already inflamed gums: If biofilm has accumulated for a long time, gums become swollen and tender; even light contact can cause bleeding.
Dentists recommend a simple guideline: "If it slides in gently, it's appropriate." Don't force it if it requires pressure or causes immediate pain. For bleeding, minor bleeding during gentle, proper cleaning may indicate existing gum inflammation that improves with consistent care. However, severe pain, heavy bleeding, or recurring problems at the same spot warrant immediate dental consultation.
Dr. Chang recommends three key principles for using interdental brushes: stop immediately if you feel resistance, switch to dental floss for very tight gaps, and have a dentist evaluate the proper size and angle for your needs. He emphasizes that flossing isn't about force—larger brushes aren't always better. The key is selecting appropriate tools and using correct technique. Proper use can effectively reduce periodontal disease risk, but incorrect use can harm your gums instead.
