Maxillary Sinus Flashcards
What are the different air sinus present in the skull?
Frontal
Ethmoid
Sphenoid
Maxillary
When does formation of the sinuses occur?
During 3rd and 4th foetal months, with evaginations of the mucosa of the nasal cavity
Which sinuses are most well formed at birth?
Maxillary and ethmoid
-> others undergo expansion in first few years of life
What are the functions of the sinuses?
Provide resonance to the voice
Reserve chambers for warming inspired air
Reduce the weight of the skull
Which sinuses are the largest?
Maxillary
-> pyramid shaped cavity in both sides of maxilla
What are the dimensions of the maxillary sinus?
Volumetric space- 15ml in average adult
Average dimensions:
37mm high
27mm wide
35mm antero-posteriorly
What is the name for the opening of the maxillary sinus and where is it located?
Ostium- located in the medial wall and opens into middle meatus at the hiatus semilunaris
-> approx 4mm in diameter
What can disease and inflammation within the sinus do to the ostium?
Cause blockage or narrowing
Where is the alveolar canal found, what is contained within it?
Posterior wall of sinus cavity
-> contains posterior superior alveolar nerves and vessels
How are the roots of the teeth related to the floor of maxillary sinus?
Roots of maxillary molars and sometimes premolars may project into the floor of the maxillary sinus
The roots may perforate the bone so that only the mucosal lining of the sinus covers them
Which type of epithelium lines the maxillary sinus?
Pseudostratified ciliated columnar epithelium
What are the functions of cilia in maxillary sinus?
Mobilise trapped particulate matter and foreign material within the sinus
-> cilia beat to move this material toward the ostia for elimination into the nasal cavity
What are the potential dental related pathologies associated with the maxillary sinus?
Oro-Antral Communication (OAC)- Acute
Oro-Antral Fistula (OAF)- Chronic
Root in the antrum
Sinusitis
Benign Lesions
Malignant Lesions
When can an OAC occur?
When roots are closely associated/perforate sinus and extraction causes communication (breaking bone or lining) between maxillary sinus and oral cavity
What are the clinical signs of an OAC?
Splayed roots/trifurcations (problematic)- you may see bone on removal
Bubbling of blood in socket- air coming from socket
Nose holding test- hold nose and get patient to blow (be gentle as this can tear the lining)
Direct vision- seen as black hole
Echo on suction
Prolapsed lining coming through into socket
What aspects on radiographs or clinical examination suggest an OAC is more likely to occur?
Lone standing molars (predictor for OAC or fractured tuberosity)
Bone of sinus may be wrapped around/closely associated with tooth roots
How are small OACs managed?
Inform patient
If less than 2mm:
Encourage clot
Suture margins
Which post-op instructions are given following the closure of an OAC?
Avoid blowing nose, avoid balloons, avoid singing, avoid sucking through straws (avoid extra pressure)
How are larger OACs managed?
Closed with buccal advancement flap- 3 sided 2 relieving (less flared than normal) and one crestal
How is a buccal advancement flap carried out?
Raise full thickness-incise periosteum with 15 blade to loosen
Bring flap across communication with minimal tension (should stay in position freely)
Buccal bone may need to be trimmed
Suture- previously using silk stitches (2 weeks), now dissolvable can be used (may loosen too soon)
1st stitch- tacking, then placed on relieving incisions etc (aiming for primary closure)
What can occur to the sulcus when you take a BAF?
It can reduce in depth
What is an OAF?
Chronic version of an OAC (fails to heal)- occurs when communication becomes an epithelium lined tract
-> no bleeding
-> appears as small hole
What are the symptoms of an OAF?
Problems with fluid consumption (fluids from nose)
Problems with speech or singing (nasal quality)
Problems playing brass/wind instruments
Problems smoking cigarettes or using a straw
Bad taste/odour/halitosis/pus discharge (post-nasal drip)
Pain/sinusitis type symptoms (
How is an OAF managed?
Manage in the same way as OAC (close with BAF) but excise tract first
Cut vertically to remove this tube of epithelium which facilitated the chronic communication
Often associated with pus and sinusitis (flush the antrum with water and suction)- can be unpleasant for patient
What other flap options may be used if BAF fails?
Buccal Fat Pad with Buccal Advancement Flap
Palatal Flap
Bone Graft/Collagen Membrane
Rotated Tongue Flap (Historical)
How is a buccal fat pad with BAF flap carried out?
When incising Include buccal fat pad- go further into sulcus and reach fatty tissue (yellow/globular) and pull this down and suture (then put buccal flap on top)
-> May get more bruising, can get more prominent cheek bone following
How is a palatal flap carried out, why is it less likely to be used?
Incise finger shaped flap on palate and put over hole
-> pain due to exposed bone on palate
Which factors are involved in the aetiology of fractured maxillary tuberosity?
Extraction of single standing molar
Unknown unerupted molar or wisdom tooth
Pathological gemination/concrescence
Extracting in wrong order (should extract back to front to avoid this)
Inadequate alveolar support
What is also likely to occur upon fracture of the tuberosity?
OAC formation
Why is it so important to support the alveolar bone when extracting molars in the maxilla?
Helps you notice if maxilla is moving with tooth- you can stop and manage at this point
What are the signs of a fractured tuberosity?
Noise
Movement noted both visually or with supporting fingers
More than one tooth movement
Tear in soft tissue of palate
What are the management options for fractured tubersotiy?
If caught before extraction- reduce and stabilise with:
Orthodontic buccal arch wire with composite
Arch bar
Splints (lab-made)
Dissect out and close wound primarily
What are the steps of managing a fractured tuberosity if it has been splinted?
Remove or treat pulp
Ensure it is out of occlusion
Consider antibiotic and antiseptics
Post-op instructions
Remove the tooth surgically 4-8 weeks later
How is management of root/tooth in the antrum decided on?
Localise using radiographs- usually OPT, occlusal or PA
If planning to retrieve CBCT (ideally on day of surgery- so tooth hasn’t moved)
If in doubt/difficult retrieval- refer
When may a root lost in the area of the antrum be left?
If wedged between bone and lining of antrum (least likely to cause problems/sinusitis)
What are the stages in the retrieval of root in the antrum via the socket approach?
Open fenestration with care
Suction – efficient and narrow bore
Use of Small curettes, irrigation or ribbon gauze
Close as for Oro-Antral communication
What is the Caldwell Luc approach?
Caldwell Luc approach- Incise sulcus and drill hole (buccal window) in bone
What can be done if all other approaches fail when trying to retrieve root from antrum?
ENT- endoscopic retrieval
What are the causes of sinusitis?
Most are precipitated by the effects of a viral infection
-> Inflammation and oedema
-> Obstruction of ostia
-> Trapping of debris within sinus cavity
Alteration of mucociliary clearance patterns caused by:
-> Allergens
-> Inflammation
-> Anatomic abnormalities
What can occur as a result of sinusitis?
Pressure build up
Bacteria (normal flora) can stagnate and grow in the sinus and cause super-infection (Opportunistic- AB may help at this point)
What are the signs and symptoms of sinusitis?
Facial pain
Pressure
Congestion (fullness)
Nasal obstruction
Paranasal drainage
Hyponosmia
Fever
Headache
Dental pain
Halitosis
Fatigue
Cough
Ear pain
Anaesthesia / paraesthesia over cheek
What are the dental causes which can produce similar symptoms to sinusitis?
Periapical abscess
Periodontal infection
Deep caries
Recent extraction socket
TMD
Neuralgia or atypical facial pain / chronic midfacial pain
What are the indicators for diagnosis of sinusitis in a dental setting?
Discomfort on palpation of infraorbital region
Diffuse pain in the maxillary teeth- all TTP
Pain that worsens with head or facial movements (on jumping)
What are the treatment aims when managing sinusitis?
Treat presenting symptoms
Reduce tissue oedema
Reverse obstruction of the ostia
What treatments are available for sinusitis?
Decongestants reduce mucosal oedema
-> Ephedrine nasal drops 0.5% one drop each nostril up to three times daily when required (use for a maximum of 7 days)
Humidified air is also helpful (steam/menthol inhalations)
Why can ephedrine only be used short term?
Causes atrophy in lining of nose and sinuses
When are AB considered to treat sinusitis?
If symptomatic treatment is not effective/symptoms worsen
AND
Signs and symptoms point to a bacterial sinusitis
Which AB are used to treat bacterial sinsuitis?
Amoxicillin 500mg, three times a day, for 7 days
or
Doxycycline 100mg, once a day, for 7 days (200mg loading dose)
What can fungal sinusitis result in?
Expansion of the bony walls by increased mucus secretion and fungal growth
How can trauma cause sinusitis?
When the integrity of the bony cavity and sinus membrane is violated
What are examples of traumatic causes of sinusitis?
Sinus wall fractures
Orbital floor fractures
Root canal therapy
Tooth extractions
Dental Implants / Sinus lifts
Deep periodontal treatment
Nasal packing
Nasogastric tubes
Mechanical (nasal) intubation (GA for dental treatment)
Which benign lesions can occur in maxillary sinus?
Polyps
Papillomas
Antral pseudocysts
Mucoceles
Mucous retention cysts
Odontogenic cysts /odontogenic tumours expanding into the maxillary sinus
Which malignant lesions can occur in maxillary sinus?
Primary tumours- of bone or lining
Local spread from adjacent sites
