Short answer
Yes. Dental treatment does not break the fast in itself. Fillings, scaling, extractions and a local anaesthetic injection are all fine, as long as you swallow no water, medicine or blood. If you swallow water or material by mistake, or blood that is more than your saliva, the fast is broken and you make up one day. Book after iftar if it is not urgent.
The fast is broken by something reaching the throat, so dental work that keeps everything out of the throat leaves it valid. Swallowing water, filling material or blood that equals or exceeds the saliva breaks it, with qada only. An injection into the gum does not break it.
The four schools agree on this.
Explanation
The rule for the fasting person is about what goes in, not about the mouth being touched. A dentist works inside your mouth, but as long as nothing goes down your throat, the fast is untouched.
Treatment by treatment:
- Check-up and x-ray: fast is valid. See x-rays and scans.
- Local anaesthetic injection: fast is valid, like other injections that are not nutrition. See injections.
- Scaling and polishing: fast is valid if you spit the water and paste out and the suction does its job.
- Fillings: fast is valid. Bits of filling material swallowed by mistake break it, with qada only.
- Extraction: fast is valid if you spit the blood out. Swallowing blood that equals or outweighs your saliva breaks it. See bleeding.
- Mouthwash or gargling medicine: makruh; swallowing it breaks the fast.
In pain? A bad toothache or infection that needs painkillers or antibiotics by mouth is an illness that allows you to break the fast and make up the day. Allah intends ease for you. See fasting when sick.
Tips: tell your dentist you are fasting, ask for good suction and a rubber dam, and if the visit is routine, book it after iftar. Ibn Abbas reported that the Prophet ﷺ was cupped while fasting, which shows that treatment involving blood does not break the fast in itself.
The evidence
Quran, Surah Al-Baqara 2:185
شَهْرُ رَمَضَانَ ٱلَّذِىٓ أُنزِلَ فِيهِ ٱلْقُرْءَانُ هُدًۭى لِّلنَّاسِ وَبَيِّنَٰتٍۢ مِّنَ ٱلْهُدَىٰ وَٱلْفُرْقَانِ ۚ فَمَن شَهِدَ مِنكُمُ ٱلشَّهْرَ فَلْيَصُمْهُ ۖ وَمَن كَانَ مَرِيضًا أَوْ عَلَىٰ سَفَرٍۢ فَعِدَّةٌۭ مِّنْ أَيَّامٍ أُخَرَ ۗ يُرِيدُ ٱللَّهُ بِكُمُ ٱلْيُسْرَ وَلَا يُرِيدُ بِكُمُ ٱلْعُسْرَ وَلِتُكْمِلُوا۟ ٱلْعِدَّةَ وَلِتُكَبِّرُوا۟ ٱللَّهَ عَلَىٰ مَا هَدَىٰكُمْ وَلَعَلَّكُمْ تَشْكُرُونَ ﴿١٨٥﴾
The month of Ramadhan [is that] in which was revealed the Qur'an, a guidance for the people and clear proofs of guidance and criterion. So whoever sights [the new moon of] the month, let him fast it; and whoever is ill or on a journey - then an equal number of other days. Allah intends for you ease and does not intend for you hardship and [wants] for you to complete the period and to glorify Allah for that [to] which He has guided you; and perhaps you will be grateful.
Treatment that is needed is allowed, and illness permits breaking the fast.
Sahih al-Bukhari 1938
Sahih... احتجم وهو محرم واحتجم وهو صائم ...
"He was cupped while in ihram, and he was cupped while fasting."
Medical treatment involving blood does not in itself break the fast.
Where the ruling is recorded
- Radd al-Muhtar (Ibn Abidin), Kitab al-Sawm, chapter on what corrupts the fast. Blood from the gums breaks the fast only if it equals or outweighs the saliva or its taste is found.
- al-Hidaya, Kitab al-Sawm, chapter on what breaks the fast and what does not. Swallowing something not normally eaten breaks the fast with qada only.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.