Third Molars Flashcards
Patient factors and medical considerations for extraction of third molars?
Medical indications - awaiting cardiac surgery, immunosuppressed, pre-cancer therapy
Patient age - complications and recovery time increase with age.
What times do crown and root calcification of third molars occur?
Crown calcification begins between 7-10 years and finishes by age 18 years
Root calcification complete between 18-25 years
What nerves are at risk during third molar surgery?
Inferior alveolar nerve
Lingual nerve
Nerve to mylohyoid
Long buccal nerve
Pericoronitis signs and symptoms
Pain
Swelling
Bad taste
Pus discharge
Occlusal trauma to operculum
Ulceration of operculum
Evidence of cheek biting
Halitosis
Limited mouth opening
Dysphagia
Malaise
Regional lymphadenopathy
What is pericoronitis treatment?
- Irrigation with saline or CHX blunt needle under operculum (+/- LA)
- Pt. instructed on frequent warm saline or CHX mouth-rinse
- Analgesia advice
- Instruct pt. to keep fluid levels up and keep eating
- Antibiotics if infection is severe
Extraction of opposing molars if traumatising operculum
What are predisposing factors for pericoronitis?
Partial eruption and vertical or disto-angular impaction
Opposing maxillary or M3M or M2M causing mechanical trauma contributing to recurrent infection
Stress
Poor OH
White race
Insufficient space between the ascending ramus of the lower jaw and distal aspect of M2M
What radiographic signs are associated with significantly increased risk of nerve injury during third molar surgery?
Diversion of IAN
Darkening of the root where crossed by the canal
Interruption of white lines of the canal
What is the OPT needed to determine?
Presence or absence of disease (in 3M or elsewhere)
Anatomy of 3M (crown size, shape, condition, root formation)
Depth of impaction
Orientation of impaction
Working distance (distal of lower 7 to ramus of mandible)
Follicular width
Periodontal status
The relationship or proximity of upper third molars to the maxillary antrum and of lower third molars to the inferior dental canal
Any other assoc pathology
How can mild, moderate and deep impaction be explained?
Mild impaction - where the crowns of 7’s and 8’s sit at the same height
Moderate impaction - anywhere between the 2.
Deep impaction - when the crown of the 8 sits at the level of the roots of the 7
When is a CBCT required/ justified?
If close relationship between third molar and IAC is suspected (e.g. from OPT) and need further imaging to determine tooth location.
In what situation would you require PA’s of teeth following an OPT?
For caries detection - cannot always assess caries well on OPT.
What is the definition of transverse angulation/ impaction?
When the crown is buccally placed and roots are lingually placed or vice versa.
What is the word for when a 3rd molar tooth is in an odd place?
Abberant
e.g. mid-way up the ramus of the mandible
What is the angulation/ orientation of M3M’s measured against?
Curve of spee and M2M’s (which are vertical)
What are common treatment options for retained 3rd molars?
Monitor and review
Removal of M3M/ maxillary 3rd molar
Coronectomy
What are less common treatment options for retained 3rd molars?
Operculectomy
Surgical exposure - may encourage 3rd molar to erupt into mouth
Pre-surgical orthodontics
Auto-transplation
When is a coronectomy of M3M’s indicated?
When the roots of M3M are closely associated with the IAC but tooth is symptomatic
Why are operculectomy’s not commonly carried out?
Gingivae generally grows back over the tooth fairly quickly which renders them essentially useless
What is the management for asymptomatic, diseased/ high risk of disease developing M3M’s?
Surgical intervention should be considered.
If tooth has a higher risk of surgical complications, then active surveillance until symptoms develop or early disease progression has been proven.
What is the management for asymptomatic non-diseased/ low-risk of disease developing M3M’s?
Clinical review + radiographic assessment if required
Do not remove asymptomatic, low-risk M3M’s - leave.
What medical factors should be considered/ indicate prophylactic removal of M3M’s?
Patients about to start
- bisphosphonates or other anti-resorptive drugs
- Radiotherapy of head and neck
- Immunosuppressant therapy
What surgical factors should be considered/ indicate removal of M3M’s?
If the third molar lies within the perimeter of a surgical field
Mandibular fractures
Orthognathic surgery
Resection of disease (benign and malignant lesions)
What is the management for symptomatic, non-diseased/ low-risk of disease development M3M’s?
Consider other causes of pain symptoms
Leave deeply impacted M3Ms with no associated disease
Manage other diagnoses causing pain in the region:
TMD
Skin lesions
Migraines/ headaches
etc.
After what period of time, would altered sensation or nerve numbness be unlikely to recover?
18-24 months
