Impacted Teeth

What are Impacted Teeth?

Impacted tooth can be defined as the tooth that fails to erupt into the dental arch within the usual range of expected time.

Why These Teeth get Impacted? 

The tooth becomes impacted because adjacent teeth, dense overlying bone, excessive soft tissue, or a genetic abnormality prevents eruption.


Consequences of Impacted Teeth? 

Because impacted teeth do not erupt, they are retained for the patient’s lifetime unless surgically removed or exposed because of resorption of overlying tissues.

What is meant by the term “Unerupted Teeth” ?

The term unerupted teeth includes impacted teeth and teeth that are in the process of erupting.

Why This Phenomenon Occurs? 

Teeth most often become impacted because of inadequate dental
arch length and space in which to erupt, it means that, the total length of the alveolar bone arch is smaller than the total length of the tooth arch.

What are the Most Common Impacted teeth?

The most common impacted teeth are maxillary and mandibular
third molars, followed by maxillary canines and mandibular premolars.

Why the Third Molars are the most frequently impacted teeth?

Third Molars the most frequently impacted because they are the last teeth to erupt; therefore, they are the most likely to have inadequate space for eruption.

How Maxillary (Upper Jaw)  Canine and Mandibular (Lower Jaw) Premolars get Impacted?

In the anterior maxilla, the canine is also commonly prevented
from erupting by crowding of other teeth. The canine usually erupts
after the maxillary lateral incisor and maxillary first premolar. If space is inadequate to allow eruption, the canine becomes impacted or erupts labial to the dental arch.
In the anterior mandible, a similar situation affects the mandibular premolars because they erupt after the mandibular first molar and the mandibular canine. Therefore, if room for eruption is inadequate, one of the premolars, usually the second premolar, remains unerupted and becomes impacted, or erupts into a buccal or lingual position in relation to the dental arch.

What is the Primary Cause of Lower Impacted Tooth? 

During normal development, the lower third molar begins in a horizontal angulation, and as the tooth develops and the jaw grows, the angulation changes from horizontal to mesioangular to vertical. Failure of rotation from the mesioangular to the vertical direction is the most common cause of lower third molars becoming impacted.

What are the Averse Effects of Impacted Teeth?

Impacted teeth can lead to Following Problems:

  • Erupted teeth adjacent to impacted teeth are predisposed to periodontal disease.


  • When a third molar is impacted or partially impacted, the bacteria that cause dental caries can be exposed to the distal aspect of the second molar as well as to the impacted third molar.
  • When a tooth is partially impacted with a large amount of soft tissue over the axial and occlusal surfaces, the patient frequently has one or more episodes of pericoronitis.

“What is Pericoronitis? Pericoronitis is an infection of the
soft tissue around the crown of a partially impacted tooth and is
usually caused by normal oral flora.”


  • An impacted tooth causes sufficient pressure on the root
    of an adjacent tooth to cause root resorption.
  • The denture/Prosthesis above impacted teeth may compress the soft tissue onto the impacted tooth, which is no longer covered with bone; the result is ulceration of the overlying soft tissue and initiation of an odontogenic infection.
  • It may lead do Dentigerous Cyst, Keratocyst or Tumor.
  • Impacted teeth may be responsible for a variety of symptoms related to headaches and various types of Neuralgias.
  • The impacted teeth of edentulous patients can erupt towards the residual alveolar ridge, creating problems when applying a prosthesis.
  • Impacted teeth and supernumerary teeth often
    hinder the normal eruption of permanent teeth.
  • Impacted Teeth may lead to weakness of Mandible that may lead to Fracture of Jaw.
  • The presence of impacted third molars may interfere
    with OrthoDontic treatment.

How to prevent such problems to occur?

To prevent the averse effeccts of an Impacted Tooth, it is needed to be Extracted.

What is the Ideal Time of Impacted Tooth Removal?

The ideal time for removal of impacted third molars is when the roots of teeth are one third formed and before they are two thirds formed, usually during the mid- to late teenage years, between ages 17 and 20 years.

What are the ContraIndication for Removal of Impacted Teeth? 

  • The most common contraindication for the removal of impacted
    teeth is advanced age.
  • A compromised medical status may contraindicate the removal of an impacted tooth.
  • If the impacted tooth lies in an area in which its removal may seriously jeopardize adjacent nerves, teeth, or previously constructed bridges, it may be prudent to leave the tooth in place



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