Canker sore treatment
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- Kank-A Mouth Pain liquid (benzocaine 20%). Best for: Fast numbing film over a canker sore. See options on Amazon
- Dentek Canker Cover patch. Best for: Covering a sore for hours. See options on Amazon
Liquid film vs dissolving patch
| Detail | Kank-A Mouth Pain liquid | Dentek Canker Cover patch |
|---|---|---|
| Active ingredient | Benzocaine 20.0% | Menthol 2.5 mg per patch |
| How it works | Dry the sore, apply undiluted, let a film coating form | Place on the dry sore; within 30 minutes forms a gel-like bandage |
| Ages | 2 and older; supervise under 12 | 5 and older |
| Limit | Up to 4 times daily; not more than 7 days unless directed | See a doctor if symptoms persist for 7 days |
Details are from each product's DailyMed label.
The two approaches suit different needs. The benzocaine liquid numbs quickly and can be reapplied up to 4 times a day. The patch covers the sore for hours, which can help during meals or talking, but cannot be removed until it dissolves.
Using benzocaine liquid
- Dry the affected area.
- Apply the medication undiluted with the applicator.
- Allow a few seconds for the coating to form.
- Use up to 4 times daily, or as directed by a dentist or doctor.
Children under 12 should be supervised, and children under 2 should not use it. Avoid contact with the eyes and with clothing, and cap the bottle tightly to avoid evaporation.
Methemoglobinemia warning
The Kank-A label warns that benzocaine may cause methemoglobinemia, a serious condition that reduces the amount of oxygen carried in blood and must be treated promptly. It can occur even if you have used the product before. Stop use and seek immediate medical attention if you or a child develops pale, gray or blue colored skin, headache, rapid heart rate, shortness of breath, dizziness or lightheadedness, or fatigue or lack of energy.
Do not use it if you have a history of allergy to local anesthetics such as procaine, butacaine, benzocaine or other caine anesthetics, and do not use it for teething in children under 2. For teething, see our teething gel guide.
Using a canker cover patch
- Pat the sore dry with a tissue if possible.
- Place the patch on a clean, dry finger, white side up.
- Put the white side on the sore and hold for 20 seconds.
- Within 30 minutes it forms a clear, gel-like bandage that covers the sore for hours before dissolving.
- Do not remove the patch before it dissolves.
The Dentek label says consult your dentist or doctor before using.
When to see a dentist or doctor
The benzocaine label says if sore mouth symptoms do not improve in 7 days, if irritation, pain or redness persists or worsens, or if swelling, rash or fever develops, see your dentist or doctor promptly. The canker cover label gives similar advice. Also get checked for very large or frequent sores, sores that make it hard to eat or drink, or a sore that does not go away.
What is in each product
The Dentek Canker Cover patch lists inactive ingredients including citrus medica fruit, povidone, colloidal silicon dioxide, carbomer 934, xylitol, sea salt and magnesium stearate. The Kank-A liquid label adds practical notes: do not purchase it if the package has been opened, cap it tightly after use to avoid evaporation, and avoid contact with the eyes, clothing and household surfaces. If you have a history of allergy to any caine anesthetic, choose a non-benzocaine option and ask your dentist. Keep both products out of reach of children.
Mouth care during a canker sore
- Brush gently around the sore with a soft brush; see our electric toothbrush guide for soft brush heads.
- An alcohol-free rinse may be more comfortable; see our alcohol-free mouthwash guide.
- Avoid foods that sting, such as very spicy or acidic foods, until it settles.
- Keep products out of reach of children; if more than used for pain is swallowed, contact a Poison Control Center right away.
What to look for when you buy
Kank-A Mouth Pain liquid (benzocaine 20%)
Best for: Fast numbing film over a canker sore
Its label lists benzocaine 20% for canker sore pain, forming a long-lasting film coating.
Watch out: Methemoglobinemia warning; not for children under 2.
See options on AmazonDentek Canker Cover patch
Best for: Covering a sore for hours
Its label lists menthol 2.5 mg in a patch that forms a gel-like bandage within 30 minutes.
Watch out: Do not remove before it dissolves; ages 5 and older.
See options on AmazonQuestions people ask
- What is the fastest canker sore pain relief?
- A benzocaine 20% liquid such as Kank-A numbs and forms a film; follow the 4-times-daily limit.
- Is benzocaine safe for kids?
- Not for children under 2, and supervise children under 12, per the label.
- What is methemoglobinemia?
- A serious condition that reduces oxygen in the blood; the benzocaine label lists warning signs like blue or gray skin.
- How long does a canker sore patch last?
- Dentek says it covers the sore for hours before dissolving.
- When should I see a dentist for a canker sore?
- If it does not improve in 7 days, or with swelling, rash or fever.
- Can I use a canker sore patch on a child?
- The Dentek patch label lists ages 5 and older; ask a dentist or doctor for younger children.
Sources
- Kank-A Mouth Pain (benzocaine 20%) liquid label (dailymed.nlm.nih.gov), DailyMed, U.S. National Library of Medicine
- Dentek Canker Cover (menthol) patch label (dailymed.nlm.nih.gov), DailyMed, U.S. National Library of Medicine