It is worth noting whether the patient has a history of periodontal treatment, including any current therapy or antimicrobials, as evidence suggests that contributing factors could be residual calculus, the introduction of bacteria into the gingival pockets during debridement or bacterial superinfection as a result of antibiotic treatment.[9] Periodontal abscesses secondary to foreign body impaction are identifiable through a thorough history taking from the patient. 

Although a recent and complete medical history is a requirement when examining all patients, extra emphasis should focus on diagnosed or undiagnosed diabetes due to the increased predisposition for developing abscesses in these patients.[10]

The most prevalent presenting complaint is an intra-oral swelling with or without accompanied pain.[11] Patients can report pain exacerbated on biting. Due to the loss of the periodontal structure, the tooth can feel loose. Commonly, patients can experience purulent exudate (particularly on pressure or probing), or report a bad taste associated with pus as well as the sensation of tooth elevation.  

Clinical examination is paramount in aiding the diagnosis. Typically, signs include those of periodontal diseases such as increased gingival probing depths (usually greater than 6 mm), suppuration, hypermobility, and furcation involvement. Other findings include tenderness to palpation, lateral percussion, and increased mobility. Looking at the lateral portion of the root, clinicians may notice an ovoid elevation of the gingivae.[4] The tooth will typically respond to vitality testing of the pulp through electric or thermal stimulation.

Periapical radiographs are critical in evaluating the periodontal hard tissues. Widening of the periodontal ligaments and horizontal or vertical bone loss is often expected. Periapical radiolucency is usually an indication of an endodontic abscess or a combination of a periodontal and endodontic abscess. The latter often demonstrates characteristic alveolar bone loss extending to the periapical lesions. Insertion of gutta-percha points along a sinus tract or into the periodontal pocket and identifying the point of termination with a periapical radiograph can help determine the source of infection.[10]

Darkfield microscopic examination of the abscess can help to rule out periapical endodontic abscesses due to the difference in the microflora. Alternatively, positron emission tomography is a possible option due to its high accuracy in detecting periodontal and other anaerobic abscesses in the oral cavity.[1]

Periodontal abscesses rank as the third most common dental emergency that patients present with at the dental surgery. Treatment predominantly consists of two phases: the acute management followed by definitive treatment.

Acute treatment aims to alleviate any symptoms and reduce the risk of the spread of infection.[12] Drainage of an abscess is achieved through an incision over the area of greatest fluctuant swelling on the gingiva, or through the periodontal pockets. Accompanied debridement of the periodontal pockets through mechanical scaling and antiseptic rinse removes the necrotic tissue and bacterial load; this enables the host immune response to tackle the infection. Alternatively, if the cause is an embedded foreign object, then this requires removal through debridement.

Exodontia is the recommendation where the clinician deems tooth prognosis to be poor or hopeless, whether as a result of periodontal disease or from the destruction caused by the abscess.[3]

Patients with a compromised immune system, individuals where drainage is not achievable, or those with evidence of systemic spread may benefit from a course of antimicrobial therapy.[13] Systemic involvement may present as pyrexia, malaise, cellulitis, or lymphadenopathy.  Antibiotic selection should consider susceptibility and resistance of the bacterial strain, patient allergies, and drug interactions. Amoxicillin, in combination with clavulanic acid, is usually the first choice of antibiotic, with clindamycin recommended as an alternative for patients with penicillin allergies.[12]

Postoperatively, warm salt water rinses are encouraged, along with copious fluid intake to help with swelling reduction. The recommendation that clinicians review the patient to reassess the lesion and generate a long-term treatment plan as necessary, usually consisting of periodontal therapy.[14]

Thorough anamnesis and clinical findings are crucial in distinguishing between other oral pathologies.[15]

Periapical abscess, a history of trauma, tooth wear, fracture, caries, or deep restoration, may indicate pulpal damage. Vitality testing with electric or thermal stimulation will either provide a negative or inconclusive response. Radiographically, there can be evidence of periapical radiolucency if the patient is experiencing an acute exacerbation of a chronic periapical lesion.

Combined perio-endodontic abscesses can categorize into the primary endodontic abscess with secondary periodontal involvement, primary periodontal abscess with secondary endodontic involvement, or a true combined periodontal-endodontic abscess. Correct diagnosis relies on collaborating the history, clinical examination, and special investigations such as vitality testing and intraoral radiographs.[16]

Pericoronal abscesses: abscesses from a partially erupted tooth can often mimic a periodontal abscess. Clinicians should look out for vital adjacent teeth with no increased periodontal pocketing.[3]

Partial root fracture: fractures are detectable through visual inspection, increased mobility, and tenderness. Radiographs taken from two different angles can help detect fractures. Similarly, endodontic perforations or perforations as a result of posts are also detectable through intraoral radiographs of alternative angulations.[3]

Squamous cell carcinoma: clinicians should be vigilant when assessing and treating recurrent periodontal abscesses as literature reveals cases of gingival squamous cell carcinomas mimicking periodontal disease and their associated abscesses.[17]

Self-inflicted gingival injuries: habits such as nail-biting and trauma due to objects such as pens and pins can cause similar looking lesions. These can be ruled out through history taking, and there should be considerations regarding habit dissuasion methods.

Other less common differentials include lateral periapical cyst, post-operative infection, odontogenic myxoma, metastatic carcinoma, non-Hodgkin’s lymphoma, pyogenic granuloma, osteomyelitis, odontogenic keratocyst, eosinophilic granuloma or post-surgical abscess.[3]

Periodontal abscesses characteristically demonstrate the rapid destruction of the periodontal ligament and alveolar bone. It is therefore widely accepted that periodontal abscesses can significantly influence the prognosis of a tooth and may lead to tooth loss; this is particularly true for patients who already have moderate to severe attachment loss. Forty-five percent of teeth with a periodontal abscess during supportive therapy were extracted.[18] Teeth with repeated abscess formation have a very poor prognosis.[2]

A retrospective study at the University of Iowa found that out of 109 teeth affected by periodontal abscesses, 45% of these teeth were lost compared to 55% of teeth that were successfully maintained for 12.5 years on average. They also found that more teeth with furcation involvement were lost compared to non-furcated teeth.[18]

The evidence suggests that there are poorer outcomes for teeth with existing periodontal disease and due to the rapid destructive nature of the disease, early diagnosis and treatment are crucial to improving the prognosis.[19]

If left untreated, the dental abscess can cause further breakdown of the periodontal structure, reducing the long-term prognosis of the tooth. This is particularly relevant for patients exhibiting moderate to severe periodontal disease.[3] Teeth with periodontal abscesses may require extraction in the future due to recurrent abscesses, pain, or increased mobility.[18] Untreated periodontal abscesses may result in the systemic spread of infection. Dental abscesses can progress to extra-oral head and neck swellings, lymphadenopathy, and even sepsis.[3]

It is essential to educate patients on the main contributing risk factors to tackle the periodontal abscess causes:

1. Oral hygiene- brushing twice a day along the gingival margins and using interdental aids helps reduce plaque accumulation and bacterial load.
2. Diabetes- educating patients on the bi-directional relationship between periodontitis and diabetes helps promote the importance of better diabetic control. Liaising with general medical practitioners can be beneficial in addressing this situation.
3. Smoking- offering smoking cessation advice can help reduce the patient’s risk of periodontitis as well as oral cancer and general well-being.
4. Family history- although an unmodifiable risk, awareness of susceptibility can be motivational in encouraging patients to maintain good oral hygiene and seek care earlier and more frequently.

An interprofessional team approaches can help promote patient outcomes; this may involve referral to a hygienist or periodontal specialist for regular therapy or surgery for periodontal disease.

It is also important for general medical practitioners as well as clinicians in the emergency department to recognize both signs and systems of periodontal abscesses as well as underlying contributing factors that may need addressing.