Is Toothbrushing Enough? Evidence‑Based Truths About Interdental Care — Dr. Hiroshi Miyashita, Director, Tokyo International Dental Clinic Roppongi

Experience
I am Dr. Hiroshi Miyashita, Director of Tokyo International Dental Roppongi. For many years I have provided periodontal treatment and preventive guidance. In clinic I frequently encounter patients who say, “I brush every day but my gums are swollen,” or “My exam found plaque between my teeth.” I have seen many cases where interdental plaque—areas toothbrushes cannot reach—becomes a nidus for chronic inflammation.

Expertise

  • Evidence base: I evaluate interdental care based on high‑quality studies including the Cochrane review (Worthington et al., 2019).
  • Products & indications: I understand floss, interdental brushes, and oral irrigators (water flossers), and tailor recommendations to each patient’s interdental morphology.
  • Outcome measures: I use clinical indices (Gingival Index, plaque indices) to assess short‑ and mid‑term effects in routine practice.

Authority
Systematic reviews that pool randomized controlled trials are reliable for assessing evidence quality. I apply these findings in clinical guidelines and practice.

Trustworthiness
I recommend care combining scientific evidence and clinical experience. I explain limits of evidence (GRADE ratings often low to very low) and respect each patient’s preferences and circumstances.

Key findings and clinical implications

  1. Interdental brushes can be a promising first choice
    Cochrane evidence suggests adding an interdental brush to toothbrushing is likely more effective than brushing alone at reducing gingival inflammation (GI) and plaque—especially in adults with adequate interdental spacing.
  2. Floss remains useful—individual factors are critical
    Floss is effective for tight contacts and narrow gaps. Optimal device choice depends on interdental space, manual dexterity, and patient motivation. The right tool is the one that fits the patient’s mouth and is used consistently.
  3. Oral irrigators offer mainly short‑term, adjunctive benefits
    Water flossers may reduce gingival inflammation in the short term (~1 month), but evidence for sustained benefits at 3–6 months is unclear. There is limited evidence that they outperform toothbrushing for plaque removal; treat them as adjuncts.
  4. Long‑term evidence for caries prevention and halting periodontitis progression is limited
    Current long‑term, high‑quality data showing interdental devices reduce proximal caries or prevent progression to severe periodontitis are insufficient—this indicates an evidence gap, not proven absence of effect.
  5. Safety is high, but evidence certainty is low
    Serious adverse events are rare. However, many studies are difficult to blind and enroll relatively healthy participants, so overall evidence certainty is rated low to very low. Statistical significance may not always translate to clinically meaningful benefit for every individual.

Clinical practical flow (our clinic’s recommendation)

  • Step 1: Examine interdental morphology (presence of gaps) and plaque distribution.
  • Step 2: If gaps are present, recommend appropriately sized interdental brushes; use floss for narrow contacts.
  • Step 3: If adding a water flosser, monitor clinical outcomes over time.
  • Step 4: Reassess after about 3 months; if results are insufficient, adjust tools or technique. Combine with regular professional maintenance.

Reference
Worthington HV, MacDonald L, Pericic TP, Sambunjak D, Johnson TM, Imai P, Clarkson JE. (2019). Home use of interdental cleaning devices, in addition to toothbrushing, for preventing and controlling periodontal diseases and dental caries. Cochrane Database Syst Rev; (4).

Conclusion — Message to patients
“Brushing alone may not be enough.” Science supports this important point, but the optimal interdental care is not one‑size‑fits‑all. Consider interdental spacing, ease of use, and sustainability; together we will choose the best tool for you. Evidence evolves—based on the latest science and my clinical experience, we provide practical, personalized care. Please schedule an interdental checkup.

Make an appointment for consultation today.

Tokyo International Dental Clinic Roppongi

Here is the MAP 

  • Address: 5-13-25-2nd Floor, Roppongi, Minato-ku, Tokyo
  • Phone: 03-5544-8544
  • Closest Stations: 
  • Azabu Juban (Toei Oedo Line take exit7）
  • https://youtu.be/iIeG91YEJTA 　The way to the clinic from Ohedo Line Exit7
  • Azabu Juban (Tokyo Metro Namboku Line exit 5a )
  • https://youtu.be/3yniFSfucGg　The way to the clinic from Namboku Line Exit 5a 
  • Roppongi (Hibiya Line exit 3)

We look forward to helping you achieve a healthy, beautiful smile!

医療法人社団EPSDC