OS - maxillary sinuses Flashcards
what roots of what teeth are most commonly found in maxillary sinuses?
palatal roots of maxillary molars
what are maxillary sinus peri-operative complications?
endodontic materials or instruments intruded in to the sinus
why may pts think sinus pathology is toothache?
the trigeminal nerve (maxillary division) innervates the teeth and sinus
what can sinus pathology present as inside the mouth?
cancer
erosion of the bone in the mouth
a cyst in the antrum can displace teeth and cause communication in to oral cavity
what are the paranasal sinuses lined by and what does this produce?
ciliated epithelium (respiratory epithelium) - produces mucous
what are the paranasal sinuses?
air-containing sacs lined by ciliated epithelium communicating with the nasal cavity
what are the 4 paranasal sinuses?
bilateral frontal, ethmoid, sphenoid, and maxillary
what is the cause of pan sinusitis?
infection in one sinus that is in close proximity to the draining ostium
what are the said physiological functions of the paranasal sinuses?
humidification of air
filtering air
production of voice
lightening the weight of the head
crumple zone (protects force on the face to brain)
what do the ethmoid sinuses look like radiographically?
small air cells
where does the sphenoid sinus lie?
under sella turcica
are the frontal sinuses symmetrical?
no
why do sinuses present as black on a CT scan?
air filled
how are secretions drained from the maxillary sinus?
against gravity - ciliated epithelium beat in a spiraling pattern to ostium
what is the maxillary sinus also known as?
the antrum of highmore
what shape is the maxillary sinus and how much volume does it hold?
pyramidal shape, volume of 15-30mls
when does the maxillary sinus start to develop?
3 months IUL
what size is the maxillary sinus by the age of 9?
60% of its max size
when does maxillary sinus become its full size?
18 years
what issues arises with the continuous growth of the maxillary sinus throughout life?
more likely to cause OAC and fracture tuberosities
what anatomical features are related to the maxillary sinus?
orbit
infra-orbital nerve
nasolacrimal duct
posterior teeth
lateral wall of the nose
pterygopalatine fossa
maxillary artery
what is Schneiderian membrane?
respiratory epithelium that lines the sulcus
where do all paranasal sinuses drain through?
lateral wall of the nasal cavity
where does the maxillary sinus drain to?
middle meatus through a 2.4mm diameter ostium (2/3rds up the medial wall of the sinus)
where does the frontal sinus drain to, what innervates it, and what supplies its blood?
drains to: middle meatus
innervated by: supraorbital nerve
blood supply: anterior ethmoidal arteries
where does the sphenoid sinus drain to, what innervates it, and what supplies its blood?
drains to: sphenoethmoidal recess
innervated by: posterior ethmoidal nerve
blood supply: pharyngeal branch of maxillary artery
where does the ethmoidal air cells (ant, post, middle) drain to, what innervates it, and what supplies its blood?
anterior - drains to middle meatus
middle - drains to lateral wall of middle meatus
posterior - drains to lateral wall of superior meatus
innervated by: maxillary nerves
blood supply: maxillary artery
what can infection in the frontal sinuses co-infect?
maxillary and ethmoidal sinuses (pan sinusitis)
what is the physiological role of the maxillary sinus thought to be?
immunological defense
how can you investigate the maxillary sinus?
CT/MRI
endoscopy - more commonly used for antral pathology
antral tap (in the past) - small hole for drainage
transillumination - if illuminates = healthy
what sinuses can be investigated through transillumination?
frontal and maxillary
why is the maxillary sinus of significance to dentistry?
roots of the upper molars/ premolars closely related to the antrum and share common innervation
dental procedures complicated by problems involving the antrum - OAC, roots in antrum, fracture tuberosity, extruded root canal materials
what is antral lining prolapse?
lining of the antrum stays intact but prolapses down
what is common pathology associated with the maxillary sinuses?
infective sinusitis-bacterial, viral, fungal, 10% dental origin, OAF
fractures
tumours/cysts
what causes non-infective sinusitis?
allergic, vasomotor, septal deviation, foreign body
what causes acute infective sinusitis?
bacterial infection which follows viral infection
caused by strep. pneumoniae, H. influenzae (resp bacteria)
how do you diagnose acute infective sinusitis?
clinical grounds only
what history will a pt present with with acute infective sinusitis?
pain
tenderness across area worsens on bending over
no swelling
posterior teeth TTP
post nasal drip
mucopurulent discharge
poor response to nasal decongestants
how do you manage acute sinusitis in fit and healthy pts?
menthol inhalation
how do you manage acute infective sinusitis in pts with prolonged severe infection/ underlying immunocompromisation?
amoxicillin 500mg TDS for 7 days OR doxycycline 100mg (200mg first day) for 7 days.
how does inhalation manage sinusitis?
shrinks linings and opens ostium, allowing contents to discharge through ostium in to lateral wall of nose, nasopharynx then oropharynx
how does sinusitis become self limiting?
mucopurulent out of mucous
why is amoxicillin not prescribed for sinusitis anymore?
due to its widespread use during covid
what can mechanically obstruct sinuses causing sinusitis?
oedema of nasal mucosa
polyps
septal deviation
what can result in impaired mucus clearance?
poor ciliary action
abnormally thick or sticky mucous (cystic fibrosis)
how does chronic sinusitis present?
ongoing low-grade symptoms
management of chronic sinusitis?
antral lavage
intranasal antrostomy
metronidazole with amoxycillin/ erythromycin
what is an oral antral fistula?
persistent epithelial lined tract (must be excised)
what does chronic sinusitis suggest in the absence of OAF?
immunocompromise
what is an antral mucocoele?
intra antral pathology - cyst formed in antral lining of schneiderian membrane
what can an antral mucocoele lead to?
chronic sinusitis if it gets too big that it obstructs
what are 3 complications of sinusitis?
brain abscesses
orbital cellulitis
cavernous sinus thrombosis
what are the causes of OAC?
extraction of posterior teeth
tuberosity fracture
middle third fracture
malignancy/ pathology
what are symptoms of an OAC?
passage of fluid down nose
passage of air into mouth
alteration of voice
unilateral epistaxis or nasal obstruction
what can an untreated fistula cause?
persistent sinusitis
unilateral nasal discharge
intra-oral antral polyp
cacogeusia and facial pain
OAC management?
ideally close immediately - buccal advancement flap
plate or modified denture
antibiotics, ephedrine drops, mucolytic inhalations
avoid nose blowing
what size of OAC can close spontaneously?
less than 5mm
where does maxillary sinus drain?
middle meatus through an ostium 2/3rds up the medial wall of sinus
what innervates the maxillary sinus?
second branch of trigeminal - maxillary nerve
