The most common site of pericoronitis is impacted or partially erupted lower 3rd molar.

The most common cause behind
peri-coronal inflammation is the entrapment of plaque and food debris between tooth
crown and overlying
operculum (gum flap).  This is an ideal area for the growth of bacteria and it is difficult to keep clean;
also, there is the constant possibility of acute inflammation of
peri-coronal (around the crown of the tooth) sites.  It may be
due to trauma, occlusion or entrapment of foreign body below the
peri-coronal flap / operculum.

Risk Factors:

  • Presence of unerupted / partially erupted tooth / teeth in communication with the oral cavity.  Lower 3rd molars (which
    are vertically and disto-angularly impacted) are most commonly affected
  • Presence of periodontal pocket adjacent to unerupted / partially erupted teeth
  • Opposing tooth / teeth in relation to peri-coronal tissues surrounding unerupted / partially erupted tooth / teeth
  • Previous history of pericoronitis
  • Poor oral hygiene
  • Respiratory tract infections & tonsillitis
  • Age (20 - 29 year age group; the condition was rarely seen before 20 or after 40).
  • Emotional stress
Last Updated 8th January 2020
Photos of Pericoronitis / Operculitis effecting Lower Jaw Wisdom Teeth
Pathogenesis of Pericoronitis
Pericoronitis is inflammation in the soft tissues (such as the gingiva and dental follicle) surrounding
the crown of a partially erupted tooth, usually the
lower 3rd molar (wisdom tooth).

It generally does not arise in teeth that erupt normally; usually, it is seen in teeth that erupt very slowly or become impacted
and it most commonly affects the lower 3rd molar.

Once the
follicle of the tooth communicates with the oral cavity, it is thought that bacterial infiltration into the follicular space
initiates the infection.

The soft tissue covering over a partially erupted tooth is known as
peri-coronal flap or gingival operculum.  Maintenance of
oral hygiene in such area can be very difficult to achieve by normal methods of oral hygiene.

There was no significant difference between the sexes.

A seasonal variation is noted with peak incidences occurring in June and December.

Bilateral (both sides)
pericoronitis is rare and suggests underlying infectious mononucleosis (Glandular Fever).
Pericoronitis can be classified as acute, sub-acute and chronic pericoronitis.


Acute pericoronitis is of sudden onset, short lived but having significant symptoms, such as varying degrees of inflammatory
involvement of the
pericoronal flap. There is also a presence of systemic involvement. Usually, the acute form of
is seen in the patients having poor oral hygiene.

Acute Pericoronitis – Clinical Features

  • Caused 2nd to occlusal trauma from maxillary (upper) 3rd molar on retro-molar region (area behind the lower wisdom
  • Operculitis (Inflammation of the operculum)
  • Severe redness + soreness
  • Continuous severe pain
  • Localised intra-oral swelling
  • Trismus (limited mouth opening)
  • Fœtor ex ora (bad breath)
  • Lymphadenitis ++
  • Malaise
  • Leucocytosis
  • Dysphagia (problems eating)
  • Pyrexia (fever) associated with tachycardia (increased heart rate) if neglected

Sub-Acute Phase of Pericoronitis – Clinical Features


Pericoronitis may also be classified as chronic / recurrent.  Acute pericoronitis occur repeatedly and periodically.  It may
cause few symptoms but some signs are visible at the time of intra-oral examination.  The
chronic type mostly seen with
good-moderate oral hygiene.

The main complaint is of a dull pain or mild discomfort lasting a day or two, with remission lasting many months.  
Cacogeusia (bad taste) may also be present.  Pregnancy and fatigue are associated with an increased occurrence of

Chronic Pericoronitis – Clinical Features

  • Localised tissue swelling & redness
  • Soreness
  • Continuous dull pain
  • Localised rise in temperature
  • Lymphadenitis +

These include debridement of plaque and food debris, drainage of pus, irrigation with sterile saline,
chlorhexidine or
hydrogen peroxide & elimination of occlusal trauma.

In the past the use of caustic agents such as
chromic acid, phenol liquefactum, glacial trichloroacetic acid or Howe’s
ammoniacal solution
was advocated to control pain by placing a small amount on a cotton pledget under the operculum.

The resultant
chemical cauterisation of the pain nerve endings in the superficial tissues gave rapid pain relief; however, the
use of these toxic chemicals in the oral cavity is no longer encouraged.

Ozone has been put forward as a local antimicrobial that might be a useful adjunct in the treatment of pericoronitis;
however, there is no research available to show its efficacy as yet.

In addition to local pain and swelling, if the patient is exhibiting regional or systemic signs and symptoms, antimicrobial
therapy (such as
metronidazole) is recommended; however, it should be emphasised that it is as an adjunct rather than a
1st line treatment.  These are all active against anærobic bacteria, which are the predominant microflora found in

Once the
acute phase of the pericoronitis has passed, operculectomy has been used as a preventive measure.
Useful Articles:

J Ir Dent Assoc 2009.  Pericoronitis – A Treatment & A Clinical Dilemma

Int J Laser Dent 2014.  Case Report.  Minimally Invasive Management of Pericoronal Abscess using a 810 nm Diode Laser

Int J Dent Med Res 2015.  An Insight into Pericoronitis