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Periapical Abscess With Sinus Vs Without Sinus

The difference between a periapical abscess with sinus vs without sinus, is that the former is a progression of the latter. That means both conditions are on the same spectrum for the same oral condition.

Periapical abscess with sinus
Periapical abscess with sinus

Therefore, you can gauge how far along you are with your tooth abscess depending on whether or not a sinus tract is present in your mouth.

With sinus vs Without sinus

In a nutshell, a periapical abscess without a sinus is the predecessor or precursor to a periapical abscess with a sinus. They are the same type of infection, it's just that the form without a sinus is an earlier stage than the form with a sinus.

Stages of a periapical abscess:

  1. Periapical abscess without sinus.

  2. Periapical abscess with sinus.

  3. Gum boil formation.

Essentially, they're both on the same spectrum for the same oral disease. One of them is the more severe or advanced version of the other which can occur when the condition is left untreated.

Comparison table

Below is a comparison table showing you the differences in signs and symptoms for each of these stages of the same abscess.


With Sinus

Without Sinus


Gum boil

No gum boil


Maybe painful

Likely painful



No pus

Infection origin

Root tip

Root tip


Large radiolucency

​Large radiolucency

Tooth vitality



We wish to reiterate that the with sinus form of a periapical abscess is simply an advanced progression of the without sinus.

Periapical abscess with sinus

A periapical abscess with a sinus tract is a late stage tooth abscess.

The infection has progressed enough that it has carved a tunnel through the jaw bone from the root tip to the surface of the gums, thus forming a pimple on the gums.

  • The carved out tunnel is the infection destroying the jaw bone by hollowing it out. This hollowed out pathway is what is known as a sinus tract.

  • The pimple on the gums is merely orifice or opening of a sinus tract.

gum boil
gum boil

Basically, the sinus tract is a pathway that connects the abscess from the tooth root tip in the jaw bone to the gums in the mouth.

Signs & symptoms

The most distinctive trait for this condition is the presence of a sinus tract.

  • Pimple on the gums.

  • Pus that oozes out of the boil.

  • May or may not be painful.

  • Shows up as a big dark radiolucency on PA x-rays.

  • Tooth is dead.

x-ray of tooth with halo around root after root canal - outlined

The x-ray above shows a molar with a periapical abscess that was treated with endodontic therapy (root canal).

small gum boil behind the molar
small gum boil behind the molar


Treatment for a periapical abscess that has a sinus tract will need a root canal along with antibiotic placement inside of the canals. It will be a multi visit procedure.

What to expect:

  1. You will be thoroughly numb for all visits.

  2. Root canal will be started on the tooth.

  3. Nerve will be removed and the interiors of the canals will be disinfected.

  4. An antibiotic paste will be placed inside of the canals.

  5. Temporary restoration placed.

  6. Wait 1-2 weeks for antibiotics to get rid of the sinus.

  7. If the sinus tract doesn't go away, your dentist may need to do another round of the antibiotics.

  8. Once the gum boil resolves, your dentist can fill in the root canal.

Periapical abscess without sinus

A periapical abscess without a sinus tract is a tooth abscess in the beginning stages.

The tooth infection has just begun and it hasn't caused enough damage to form a sinus tract which is why it doesn't have one. As of the moment, the abscess is localized to just the tip of the infected tooth root.

However, if you leave this condition untreated it will progress and eventually develop a sinus tract and also a gum boil.

Signs & symptoms

Often times, most patients don't know that they even have this condition because there are no oral manifestations. The sinus tract is not present so the chances of you knowing you have this are quite slim.


  • No pimple on the gums.

  • No purulence present since there is no sinus tract.

  • May or may not be painful.

  • Tooth is non-vital.

  • Often has a large radiolucent lesion on PA x-ray.

Periapical abscess without sinus that has been root canal treated
Periapical abscess without sinus that has been root canal treated

The x-ray above shows an upper front lateral incisor that had a periapical abscess but without a sinus tract present. It has been successfully treated with a root canal.


The treatment for a tooth with a periapical abscess and without a sinus is the same as one with a sinus tract present. It will be a multi visit endodontic appointment (root canal) where antibiotics will still be required.

What to expect:

  1. Expect to be numb for all of the visits.

  2. Root canal will be initiated on the tooth.

  3. Infected nerve will be removed and the canals will be disinfected.

  4. An intracanal antibiotic paste will be placed.

  5. Temporary restoration placed.

  6. Wait 1-2 weeks for the antibiotics to kill the abscess.

  7. Once the tooth is free of bacteria and infection, your dentist can fill the canals and complete the procedure.

The Verdict

Both a periapical abscess without a sinus and one with a sinus are the same type of infection. It's just that one of them is the more advanced form of the other when it is left untreated and allowed to progress.

The main differentiating factor between how the two look is that the one with a sinus will often have a pimple on the gums. Treatment for both of these two stages of a dental abscess are the same. They will require root canals and also intracanal antibiotics to rid the tooth of the infection.



David Chen 200 x 200.jpg

About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

Association Memberships:

Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!

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