An untreated dental abscess: what complications can arise

A dental abscess is not just a simple toothache, but a serious condition that requires immediate treatment. Caused by a bacterial infection localised at the root of the tooth or in the gum, the abscess leads to the accumulation of pus and severe inflammation. If left untreated, it can affect not only the affected tooth, but also the maxillary or mandibular bone, soft tissues, sinuses and even vital organs.

Although patients sometimes delay seeing a dentist in the hope that the pain will go away on its own, medical reality shows that a dental abscess does not heal spontaneously. On the contrary, the longer it goes untreated, the greater the risk of local and systemic complications. This article explains in detail what happens when a dental abscess is not treated in time and what the consequences are for general health.

An untreated dental abscess is never strictly confined to the affected tooth. The bacterial infection can spread progressively, destroying surrounding structures and endangering the patient’s health. Its progression depends on how quickly treatment is administered, and every hour of delay can lead to further complications.

Spread of the infection to the maxillary or mandibular bone (osteomyelitis)

When bacteria pass beyond the root tip, the suppurative process can erode the maxillary or mandibular bone. This leads to osteomyelitis, a severe inflammation of the bone that is difficult to treat and carries a risk of recurrence. Patients describe severe pain, fever and, sometimes, limited mouth opening. Without surgical intervention and antibiotic treatment, the infection can spread throughout the body.

Soft tissue involvement: fasciitis and periapical abscesses

A dental abscess left to progress can perforate the bone and penetrate the soft tissues, causing fasciitis or periapical abscesses. Fasciitis is extremely dangerous, as it spreads rapidly along the muscle planes and can compromise breathing. Periapical abscesses, although more common, lead to significant swelling and difficulty chewing, and in severe cases require surgical drainage.

The formation of a chronic dental fistula

In some cases, the body creates an outlet for the pus, resulting in a dental fistula. This manifests as a small opening in the gum, which constantly discharges pus. Although symptoms improve temporarily, the infection remains active deep within and continues to destroy the bone and ligaments supporting the tooth 

A dental abscess that is not treated in time inevitably leads to the loss of the affected tooth. The supporting tissues – the gums, periodontal ligaments and alveolar bone – are progressively destroyed by the infection. The result is irreversible tooth loss and, in many cases, the need for complex treatments to restore function and aesthetics.

Destruction of the periodontium and tooth mobility

Persistent infection affects the periodontium, the structure responsible for anchoring the tooth in the bone. The periodontal ligaments are destroyed, deep periodontal pockets form and, gradually, the tooth becomes mobile. At this stage, chewing becomes painful and difficult. Furthermore, tooth mobility facilitates further bacterial penetration, accelerating the destruction.

Irreversible gum recession

Repeated inflammation leads to gum recession, exposing the tooth root. This is more porous than enamel, which allows bacteria to adhere and colonise more easily. Gum recession is irreversible and is not only unsightly but also dangerous for the stability of the tooth, increasing the risk of new periodontal abscesses. 

When the damage is advanced and the tooth can no longer be saved through endodontic treatment or periodontal therapy, the only option left is extraction. This paves the way for complex prosthetic solutions: dental bridges, dentures or implants. In severe cases, the infection can also compromise the alveolar bone, making it difficult to insert an implant and prolonging the treatment period.

“A concrete example is that of a 22-year-old patient who arrived at the clinic as an emergency with severe swelling of the lower jaw, which had developed following incomplete dental treatment. The infection worsened rapidly and required immediate hospitalisation, intravenous antibiotics and surgery to drain the pus-filled collection. Ultimately, the affected tooth had to be extracted. The outcome was favourable, but this case shows just how risky an untreated dental abscess can be and how important it is to see a doctor at the first signs of infection,” explains Dr Bianca Spătaru, a dentist at DENT ESTET Sibiu and a resident in Maxillofacial Surgery.

An untreated dental abscess does not remain confined to the oral cavity. As the infection spreads, serious complications can arise in the head and neck, areas rich in anatomical spaces and vital structures. These complications may require hospitalisation and multidisciplinary treatment (dental, ENT, and oral and maxillofacial surgery).

Maxillary sinusitis caused by an upper dental abscess

If the affected tooth is located in the maxilla, the infection can spread to the maxillary sinuses, particularly in the area of the upper molars and premolars. This leads to perforation of the sinus membrane and the development of odontogenic maxillary sinusitis. Symptoms include sinus pain, nasal congestion, purulent discharge and fever. Treatment requires collaboration with an ENT specialist, as it is much more complex and prolonged.

Persistent lymphadenopathy (swollen lymph nodes)

The lymphatic system reacts to infection by inflaming the regional lymph nodes, a phenomenon known as adenopathy. These become enlarged, tender and painful on palpation. In persistent infections, lymphadenopathy may remain present even after local symptoms have subsided, indicating ongoing immune stimulation and an infectious focus that is still active.

Retropharyngeal or parapharyngeal abscess – ENT emergencies

One of the most dangerous complications of an untreated dental abscess is the spread of infection into the deep spaces of the throat, leading to a retropharyngeal or parapharyngeal abscess. These are major medical emergencies, as they can compromise the airways due to the pressure exerted by the pus-filled collection. The patient experiences difficulty swallowing, laboured breathing and, in severe cases, a risk of suffocation. Surgical intervention and intravenous antibiotic therapy are essential to save the patient’s life. 

An untreated dental abscess is not confined to the oral cavity. As bacteria enter the bloodstream (bacteraemia), the infection can spread throughout the body. This process has serious consequences and can be life-threatening, particularly if emergency treatment is not provided.

Ludwig’s angina – a severe throat infection

One of the most serious complications is Ludwig’s angina, a rapidly progressing infection of the floor of the mouth and the cervical region. This causes massive swelling, which can push the tongue upwards and block the airways, leading to a risk of suffocation. The patient experiences severe pain, difficulty breathing and swallowing, and treatment often requires surgery and intensive care support.

Sepsis (generalised infection of the body)

In cases where bacteria enter the bloodstream, sepsis may develop – a life-threatening systemic infection. Sepsis affects multiple organs, including the lungs and kidneys, and can progress to septic shock. Blood tests show significantly elevated inflammatory markers, and the patient requires intensive treatment with intravenous antibiotics and continuous monitoring.

Bacterial endocarditis in patients with pre-existing heart conditions

Patients with artificial heart valves or other heart conditions are at increased risk: bacteria from a dental abscess can attach to the heart valves, triggering bacterial endocarditis. This complication is extremely dangerous and can lead to heart failure or even death. Therefore, antibiotic prophylaxis prior to any dental procedure is essential in these patients. 

A dental abscess does not only affect the local area or the structures supporting the tooth. In the long term, a persistent infection can have a negative impact on the health of the whole body. Numerous studies have demonstrated links between untreated dental infections and the onset or worsening of certain chronic diseases, which makes prevention and early treatment essential.

The link between dental infections and cardiovascular disease

Bacteria from the oral cavity can enter the bloodstream, where they trigger systemic inflammation. This contributes to the development and progression of atherosclerosis, increasing the risk of heart attack and stroke. Patients with periodontitis and untreated dental abscesses have a higher incidence of cardiovascular disease compared to those with good oral hygiene.

Possible renal or joint involvement in chronic infections

Chronic dental infections, including abscesses, can contribute to the development of complications affecting the kidneys or joints. The mechanism is linked to the deposition of immune complexes formed as a result of persistent infection. These can trigger glomerulonephritis (kidney damage) or reactive arthritis, leading to symptoms that extend beyond the dental sphere.

Systemic effects in immunocompromised patients (diabetes, cancer, etc.)

Patients with diabetes, cancer or other conditions that lower immunity are far more vulnerable to a dental abscess. In these patients, infections progress more rapidly, the risk of systemic complications is higher, and healing is delayed. In such cases, even a seemingly minor abscess can become a life-threatening emergency, requiring hospital treatment.

“Unfortunately, there are situations where a dental abscess can endanger the patient’s life. This happens particularly in people with other health problems, which make surgical treatment of infections that have reached advanced stages impossible. In such cases, the infection can spread rapidly to vital organs, and medical options become extremely limited due to comorbidities.” – Dr Bianca Spătaru

That is why we must be aware of the high risk of dental infections in immunocompromised patients, for whom prevention and regular check-ups are all the more important.

“My message to patients is clear: go for regular dental check-ups and do not delay seeing a dentist if you have an old dental filling, notice signs of an abscess or suspect a dental problem. Timely intervention makes the difference between a simple treatment and a situation that could be life-threatening.” – Dr Bianca Spătaru

Conclusion

An untreated dental abscess is a genuine medical emergency, with the potential to cause serious complications: from tooth loss, damage to the sinuses and throat tissues, to systemic infections such as sepsis or bacterial endocarditis. Its impact is not limited to the oral cavity, but can affect the entire body, increasing the risk of cardiovascular, renal or joint diseases.

“In my practice, I have encountered both young people who have lost their teeth due to an ignored abscess, and patients with serious illnesses for whom the dental infection has become a life-threatening condition. That is why seeing a dentist in good time is essential,” explains Dr Spătaru.

Prevention remains the safest approach: proper oral hygiene, regular dental check-ups and immediate treatment of tooth decay or dental infections. When faced with a dental abscess, time is of the essence – the sooner you see a dentist, the greater the chances of a full recovery and of saving the tooth.