OVERVIEW

What is primary failure of eruption?

Primary failure of eruption (PFE) refers to the complete or partial failure of tooth eruption despite a clear eruption pathway, caused by disordered eruption mechanisms rather than mechanical obstruction, without ankylosis. It can occur in both primary and permanent teeth.

Is primary failure of eruption common?

It is extremely rare, with reported prevalence as low as 0.06%.

Are primary failure of eruption and mechanical failure of eruption the same condition?

No, they are different.

Primary failure of eruption and mechanical failure of eruption share similar early manifestations—both present as failed tooth eruption—and require careful analysis for differentiation.

Mechanical failure of eruption is caused by physical barriers, such as impacted adjacent teeth or insufficient space, which hinder normal eruption. The tooth can erupt after removing the obstruction.

SYMPTOMS

What are the manifestations of primary failure of tooth eruption?

During an oral examination, the dentist may observe the absence of one or multiple teeth (eruption not penetrating the gums) or notice one or more teeth ceasing to erupt without mechanical obstruction (penetrating the gums but not fully erupting to the occlusal level).

Teeth with eruption failure are mostly molars and premolars, leading to noticeable unilateral or bilateral posterior open bite.

What are the consequences of primary failure of tooth eruption?

Due to misaligned or incomplete dentition, patients may struggle with thorough oral hygiene, increasing the risk of food impaction, plaque buildup, and poor oral health. This can result in tooth decay or gingivitis, potentially progressing to pulpitis, periapical periodontitis, or periodontal disease, further causing loss of remaining dentition and impacting quality of life and overall health.

Additionally, since primary failure of tooth eruption is difficult to diagnose, it is often misdiagnosed as mechanical failure of tooth eruption. Orthodontic treatment based on this misdiagnosis may lead to ankylosis of the affected tooth.

CAUSES

What is the etiology of primary failure of tooth eruption?

The exact etiology remains unclear.

It is generally considered to be a disorder of the tooth eruption mechanism, associated with mutations in the parathyroid hormone receptor gene PT202R. Some studies also suggest a possible familial link, with affected families often having other cases of primary failure of tooth eruption.

DIAGNOSIS

What tests are needed for primary failure of tooth eruption?

• Oral examination: Assess the eruption status of teeth and the condition of the mucosa.

• X-ray or CBCT scan: Analyze the mechanism of eruption obstruction through imaging to determine if there is mechanical obstruction and guide subsequent treatment.

• Genetic testing: Definitive diagnosis of primary failure of tooth eruption relies on detecting PT202R gene mutations to prevent misdiagnosis and inappropriate treatment.

What conditions should be differentiated from primary failure of tooth eruption?

Diagnosing primary failure of tooth eruption requires ruling out certain systemic or syndromic diseases, such as regional cleidocranial dysplasia, regional dental dysplasia, Alber-Schönberg osteochondrosis, and GAPO syndrome. These rare conditions are characterized by tooth eruption disorders.

Additionally, other types of tooth eruption failure must be excluded, such as mechanical failure of eruption (MFE) or isolated ankylosis, which presents with infraocclusion, lack of normal physiological mobility, and absence of periodontal ligament space on X-ray.

TREATMENT

Which department should I visit for primary failure of tooth eruption?

Dentistry, Orthodontics.

Does primary failure of tooth eruption require hospitalization?

Usually not.

How is primary failure of tooth eruption treated?

Generally, treatment depends on the patient's age and condition:

• For permanent teeth with fully developed roots, extraction is usually recommended. Three months later, restorative treatments such as fixed bridges, implants, or removable partial dentures may be performed based on the number and location of missing teeth.

• For younger patients with incomplete root development, direct or indirect restorative treatments are advised to ensure occlusal stability, correct low bite or open bite, and maintain alveolar bone levels until the patient is eligible for implant placement.

• Adult patients with only mild low bite may not require treatment but should undergo regular follow-ups.

• For adult patients willing to undergo non-extraction surgical interventions, surgical measures like segmental osteotomy to reposition teeth into occlusion or distraction osteogenesis to correct severe posterior open bite may be considered.

DIET & LIFESTYLE

What should patients with primary failure of tooth eruption pay attention to in their diet?

• Avoid eating foods that are too hard or sticky and difficult to clean.

• Drink more water.

• Reduce the intake of sugary foods to minimize the risk of cavities.

• Eat more vitamin-rich foods, such as fruits and vegetables.

• Avoid spicy and irritating foods as much as possible.

What should patients with primary failure of tooth eruption pay attention to in daily life?

• Maintain oral hygiene, learn to use dental floss, rinse after meals, brush teeth correctly and effectively in the morning and evening, and patients with the means are advised to brush after lunch as well.

• Those with dentures should clean them regularly to keep them hygienic.

• Schedule regular dental check-ups.

PREVENTION

Can primary tooth eruption failure be prevented?

No.