Oral surgery Flashcards
What are some examples of reasons to surgically remove a tooth?
- gross caries so no application point for forceps
- complex root morphology
- retained roots below the alveolar bone
- impacted teeth
- displaced teeth
- ectopic teeth
- pathology
What is impaction?
occurs when there is prevention of complete eruption into a normal functional position due to lack of space or development in an abnormal position. This predisposes to pathological changes
What kind of tissues are involved in impaction?
can involve only soft tissues or hard and soft tissues
What does ectopic mean?
malpositioned due to congenital factors e.g. cleft palate involving laterals and canine position
What does displaced mean?
malpositioned due to presence of pathology e.g. cysts causing displacement of tooth/tooth germ
What does completely unerupted mean?
entirely covered by soft tissue and also partially/totally covered in alveolar bone
What does partially erupted mean?
presents intra-orally
What does ankylosed mean?
fused with alveolar bone, rare with 8s
At what age does ankylosis occur?
after middle age
What causes impacted teeth?
lack of space in the arch as a consequence of evolutionary changes and lack of an abrasive diet
What are the most commonly impacted teeth?
- mandibular third molars
- maxillary canines
- mandibular premolars/canines
- maxillary incisors
- maxillary third molars
What guidelines are referred to for the removal of third molars?
NICE guidelines
At what age do mandibular third molars usually erupt and what are the statistics of their absence?
- between 18-24yrs but can be outwith
- fail to develop in 1:4 adults
- 72% mandibular molars impacted
What are the indications for removal of mandibular third molars?
- pericoronitis
- unrestorable caries
- cellulitis/osteomyelitis
- periodontal disease
- orthodontic reasons
What are some more uncommon indications for the removal of mandibular third molars?
- prophylactic removal in medically/surgically compromised patients (e.g. radiotherapy pts, prevent future issues, hypovasculated bone)
- obscure pain
- tooth in line of fracture
- disease of follicle
- orthognathic surgery
- transplant donor
What are the relative contraindications for the removal of a mandibular third molar?
- weigh up all variables
- asymptomatic teeth
- non-compliant patients
- overt nerve involvement - risk of damage to IAN or lingual nerve
What is pericoronitis?
inflammation of the tissues around the crown of any partially erupted/impacted tooth
What are the presenting features of pericoronitis?
- trismus, pain, dysphagia, malaise, bad taste
- inflammation of pericoronal tissues, frank pus under operculum
- cheek biting and cuspal indentations on operculum
- halitosis, food packing
- can present with systemic symptoms/spread to adjacent tissue spaces
What group of the population tend to present with pericoronitis?
younger patients, late teens, twenties
What is the treatment for pericoronitis?
- local measures = irrigation, OH measures, remove trauma i.e. extract upper 8 or grind down cusps of opposing tooth
- general measures = analgesics, antibiotics if systemically unwell/immunocompromised
What is the microbiology of pericoronitis?
- predominantly anaerobic
- streptococci, actinomyces, propionobacterium, a beta-lactamase producing prevotella, bacterioides, fusobacterium, caphocytophaga and staphylococci
When are antibiotics given in a case of pericoronitis?
- only when surgical removal of cause or drainage of infection under LA not possible
- antibiotics required if there is evidence of systemic spreading infection necessitating urgent referral for hospitalisation
What are the four treatment choices for pericoronitis?
1) conservative
2) operculectomy (not recommended)
3) removal
4) coronectomy
What kind of radiograph would be taken to assess a patient before removal of mandibular third molars and what can be visualised?
ideally OPG - visualise all tooth and adjacent structures including bone, tooth morphology and number and shape of roots, hypercementosis, depth of bone, follicular pathology, external root resorption, caries
What are indications of proximity to the ID nerve?
- IDC narrowing/darkening of canal as nerve crosses root, loss of white lines, deflection/deviation of IDC, dilaceration or bifid roots, change in colour of roots when crossed by nerve so area appears darker
What are the four angles of impaction?
- vertical
- mesial
- distal
- horizontal
What is the most common angulation of impaction in mandibular third molars?
- mesioangular (40%)
- vertical (30-38%)
What are the radiographic signs of a close relationship between the lower third molar and IDC?
- diversion of IDC
- darkening of root as it crossed by IDC
- loss of lamina dura of IDC
- narrowing of IDC
- deflection of roots as they approach IDC
- juxta apical area - appears to be a free floating apex on one side of canal which seems to be independent of root on other side of canal
What is a juxta apical area?
well circumscribed radiolucent area lateral to the root rather than at the apex.
The majority of IAN canals sit where in relation to the third molar?
lingual aspect
How are the IAN bundle organised in the canal?
artery and vein in upper part of canal, nerve in lower aspect
How does the type of bone the IAN is running through affect its visualisation on a radiograph?
- if sitting in the lingual cortical bone, (two cortical outer plates of mandible), a lamina dura is visualised as it is formed by the cortex
- if sitting in medullary bone (in centre, sandwiched between cortical plates), no cortex to see a lamina dura so difficult to detect
What is the incidence of post operative alteration in sensation in the lower lip following IANB?
- short term - 5% (weeks or months)
- long term - less than 1%
What is the incidence of post operative alteration in sensation in the tongue following IANB and lingual block?
- short term - 10%
- long term - less than 1%
- taste - can be affected
What is thought to be a common cause of lingual nerve sensation alteration?
lingual retraction
What is an alternative surgery option if there is high risk to the IDN?
Coronectomy
What are the stages involved in a coronectomy?
- remove crown and leave roots in place
- if roots are mobile at time of coronectomy, remove
- when consenting state plan is to coronect tooth but removal may be unavoidable
- post-op risk of infection of roots 2.9%
- post-op risk of migration of roots 14-81%
Should CBCTs be routinely used in the radiographic assessment of mandibular third molars?
No - evidence shows no effect on outcome, increased radiation dose and cost
Only if conventional imaging shown close relationship and specific case may show findings which could alter management
You should warn patients of post operative complications with an incidence rate of what?
greater than 5%
What are the 5 points planned from radiograph (DPT) regarding third molar removal?
- what would path of eruption be?
- extrinsic/intrinsic obstacles to removal
- required bone removal
- point of application
- flap design
What is a mucoperiosteal flap?
A full-thickness mucoperiosteal flap includes the surface mucosa, submucosa and the periosteum
How is a mucoperiosteal flap raised for M3M removal?
- distal relieving incision up ascending ramus, around crown of 3M, include papilla between 3M and 2M and mesial relieving incision (triangular flap)
- envelope flap - no mesial relieving incision
- atraumatic elevation with periosteal elevator around gingival margins then Howarths or Rake retractor to retract buccal flap
- raise lingusl flap with Howarths/Mithcells/Molt to protect lingual nerve in selected cases only
What is the difference between a triangular flap and an envelope flap?
envelope flap has no mesial relieving incision
How is a triangular flap cut for the removal of a M3M?
1) distal relieving incision - landmark = ascending ramus (1 units length of crown of tooth)
2) peri-coronal incision cutting through alveolar crest fibres, includes papilla between 3M and 2M
3) mesial relieving incision down from 2M to depth of sulcus
How is an envelope flap cut for the removal of a M3M?
1) distal relieving incision, landmark = ascending ramus
2) peri-coronal incision cutting through the alveolar crest fibres around the 3M and extends all around the 2M
How is bone removed with burs?
using burs;
- to relieve impaction, create point of application, remove bone with round bur to create narrow gutter mesiobuccally avoiding adjacent roots
- fissue bur to deepen gutter
- 20,000-40,000RPM
How is bone removed using chisels and is this normal practice now?
lingual split technique
no longer used
In what orientation are crowns divided for surgical removal and when would this need to be done?
either horizontally or axially
- in horizontal impactions
- distoangular impactions to avoid excessive bone removal but ensuring a good application point is retained
When would roots require division before removal?
- pincer roots
- multiple roots with differing paths of removal
What root form related intrinsic obstacles can hinder removal?
convergent or divergent roots
What is the importance of the replacement of a flap back into bone?
it is essential that after surgery the flap rests on bone to avoid wound breakdown
What is the most important suture that is placed following removal of a M3M?
the one placed from the buccal tissues to the lingual tissues immediately distal to the second molar tooth to encourage good periodontal health
What quantity of suture material is best and what material is commonly used?
- the fewer sutures placed the better, to secure primary closure and haemostasis
- materials 3/0 vicryl rapide (resorbable)
What is the advised post operative regime following flap design and tooth removal?
- analgesics (+/- antibiotics)
- HSMW (hot salty mouthwash)
- soft diet
- topical ice packs
- suture removal at one week if not resorbable
- arrange follow up for difficult cases or immunocompromised pts
What are the possible complications of a flap design and surgical removal of a tooth?
- haemorrhage - primary or secondary
- loose teeth or damage to adjacent teeth/restorations/periodontium
-fractured mandible - dry socket or infection with purulent discharge
- sensory deficit
- complications generally assoc with extractions
The majority of maxillary 3M are impacted in what orientation?
vertically or mesioangularly
What kind of bone surrounds maxillary 3Ms?
thin cortical bone
In what percentage of maxillary 3Ms is there just one single short root?
74%
Why are maxillary third molars difficult to manage and to keep clean upon eruption?
- difficult due to position behind second molars, molar buttress and buccal position, therefore OH problematic
GA for removal of symptomatic lower 8s merits what?
the simultaneous removal of upper 8s, patient convenience
How are unerupted maxillary third molars removed?
- raise buccal flap, thin friable bone removed with couplands and elevator used to move tooth down, back and buccally
- avoid excessive upwards force due to possible displacement into antrum
- one suture to reposition flap
Under what conditions would you leave a maxillary impacted third molar?
asymptomatic, pathology free and deeply impacted - leave unless treatment under GA
What are the second most commonly impacted teeth?
maxillary canines
Maxillary canines are more commonly ectopic in what direction?
ectopic palatal more than buccal
Maxillary canines are normally palpable in the labial sulcus at what age?
10-11yrs
What is the aetiology of canine impaction?
- lack of space
- guidance theory suggests distal aspect of lateral incisor is guide for canine eruption
- genetic theory suggests its a product of polygenetic multifactorial inheritance;
non-resorption of deciduous teeth, ankylosis of impacted canine, contraction or collapsed maxillary arch, absence of lateral incisor to guide eruption, presence of pathology, supernumary,scar tissue in path, trauma causing disturbance in tooth germ axis, cleft lip and palate, syndromes, cleidocranial dysplasia, long path of eruption (22mm), displacement of crypt
What are the clinical signs/investigations for impacted canines?
- palpate
- evidence of rotation/tilting of adjacent teeth
- mobility/sensibility of adjacent teeth
- 6 months since contralateral tooth erupted
- presence of deciduous canine
What are the radiographic investigations for the diagnosis of impacted canines?
- parallax films - PA x2, occlusal and DPT
- CBCT
Explain the process of parallax views and how the radiographs indicate the positioning of the ectopic canine
if you move the cone of the X-ray machine in one direction, and the impacted tooth moves in the SAME direction, then the tooth is further away (palatal).
If it moves the opposite way = labial or buccal
When should you suspect that a tooth is undergoing cyst formation?
when the follicular space is enlarged beyond the general 3-4mm of space you’d expect caused by the follicle
Can a dilacerated tooth be orthodontically realigned?
no - left alone or surgically removed
What are the sequelae of canine impaction?
- resorption of incisor roots
- cystic change
- infection of cyst when close to surface mucosa, possible sinus formation
What are the treatment options for impacted canines?
1) conservative
2) interceptive
3) exposure
4) surgical removal
5) transplantation
What is the conservative treatment option for impacted canines?
do nothing
- patient unwilling to have ortho, or happy with appearance with good contact between 2 and 4 or healthy C, adjacent teeth vital
- radiographs show tooth very high, no pathology or resorption
What is the interceptive treatment option for impacted canines?
extract deciduous canine
- if pt 10-13yrs, minimal crowding, space maintenance
- if no change in position after 12mths on radiographs, alternative treatment
- 78% erupt normally following interceptive treatment
What is the exposure and alignment treatment option for impacted canines?
- well motivated pt willing to have ortho and good OH
- not grossly displaced with favourable root morphology
- best results if carried out early (open apex)
- open or closed technique
What are the open and closed techniques for the exposure and alignment of impacted canines?
open technique - apically repositioned flap or palatal window
closed technique - orthodontic bracket and gold chain allow ortho traction (better technique)
What is beneficial for pain management and healing following a palatal mucoperiosteal flap to expose and align a maxillary canine?
- have an acrylic plate (dressing plate), held on by Addams cribs to serve as protective barrier for soft tissues against masticatory wear and tear
- apply with Copack soft tissue dressing (sedative dressing) to help with pain and to cushion area
- once placed, left undisturbed for a week, pt must use mouthwash but can brush normally away from surgical site
- plate removed after a week
What is the advantage of the closed technique for exposure and alignment of impacted canines?
- closed technique with orthodontic bracket mimics physiological eruption, which means it will erupt through attached gingivae, giving good gingival contour
When would surgical removal of an impacted canine be indicated?
- patient non-compliant or satisfactory appearance with C or 2-4 contact
- advanced resorption of incisors
- malpositioned canine with difficult root morphology
What technique is used for the surgical removal of impacted canines?
- commonly palatal - flap as per exposure, often envelope flap, buccal = 3 sided or 2 sided flap
- remove overlying bone to maximum convexity of tooth and elevate
- sectioning may be required if root morphology complex or tight against adjacent teeth
- may need buccal approach to section
What is released in a bilateral envelope flap for the removal of impacted canines?
in order to cut flap bilaterally, you have to release the contents of the incisive/nasopalatine foramen
What kind of irrigation is required for the use of surgical drills and why?
saline irrigation to keep field moist, preventing overheating of bone
Why is the complete removal or follicular tissue attached at the ACJ important?
it could undergo cystic change if left behind
What is autotransplantation?
Autotransplantation refers to the repositioning of an autogenous erupted or unerupted tooth from one site to another in the same individual
What are the requirements/indications for autotransplantation?
- poor patient compliance or limited treatment time
- poorly positioned canine without ankylosis
- open apex desirable
- may simply rotate tooth around an axis
- need adequate space and bone
What is the technique of transplantation of a tooth?
- access as for removal but atraumatic elevation, avoiding contact with PDL/root, tooth ‘parked’ in tissues (often under flap just raised, somewhere moist), whilst prepare socket with bur or chisels
- socket ‘friction-fit’ avoiding heat generation
- minimal time >10mins
- may require splint immobilisation
- check tooth is free of occlusion
- post op check vitality and resorption
What is the success rate of autotransplantation and what can cause failure?
- failure rate 30% in over 9yrs often due to poor surgical technique
- internal resorption = perform RCT post op
- external root resorption = if excessive force on tooth in socket
- replacement root resorption = root replaced by bone until exfoliates
- infection
When does delayed eruption of maxillary incisors require monitoring or investigation?
- if contralateral teeth erupted 6/12 previously or in the case when both upper centrals missing one year after eruption of lower incisors
- deviation from normal sequence of eruption i.e. laterals before centrals
What is the hereditary aetiology of delayed incisor eruption?
- supernumaries
- cleft lip/palate
- cleidocranial dystosis
- odontomes
- abnormal tooth/tissue ratio
- gingival fibromatosis
- generalised retarded eruption
What are the environmental aetiological factors impacting delayed incisor eruption?
- trauma = root dilaceration
- early loss or extraction of deciduous teeth
- retained deciduous tooth
- cyst formation
- endocrine abnormalities (causing abnormalities in bone density)
- bone disease
What investigations should be done regarding delayed incisor eruption?
- history and exam
- look for retained deciduous teeth, palpable buccal/palatal mass, lack of space, adjacent teeth for tilting/crowding, erupted mesiodens/supernumaries
- radiography - parallax (2x PAs easiest)
How can incisor impactions be managed?
- remove retained deciduous tooth
- create and maintain space
- remove other obstructions and expose incisors surgically
- may require brackets to realign
- severely dilacerated incisors removed
What is the technique of incisor exposure?
- often repositioned labially so therefore flap raised taking as much attached gingiva as possible and repositioned apically and packed = open technique
- closed technique using bracket and gold chains are preferred
What is a disadvantage of the open technique for apically repositioned flap for incisor exposure?
flap repositioned in a more apical position to leave crowns exposed, can lead to poor aesthetics as if teeth continue to erupt or are orthodontically aligned, the teeth will more down but often the gingivae stays put. Resulting in exposed root - sensitivity and surface loss
Due to the possibility of root exposure with the open technique for incisor exposure, what kind of teeth is it mainly kept to?
used for teeth that are just sitting under the gingivae i.e. short distance
How does the closed exposure technique work for the exposure of incisors?
- orthodontic brackets with gold chains cemented to exposed crowns
- MP flap sutured back with gold chains exposed to allow attachment to orthodontic appliance
What is the aetiology of impacted mandibular premolars?
crowding, pathology, ankylosed deciduous teeth, supernumaries, genetic disorders
What placement of impacted mandibular premolars is palpable clinically?
lingual displacement
What kind of flap design and procedure is required for the removal of an impacted mandibular premolar?
buccal flap, avoiding damage to mental bundle, elevate or section tooth to remove as atraumatically as possible
- removal of adjacent premolar may be preferred
What kind of buccal flap is used for the removal of a mandibular premolar?
2 sided MP flap
What are the three forms of supernumary teeth?
1) supplemental = exact copy
2) conical
3) tuberculate = malformed
What is a mesiodens?
Mesiodens is a supernumerary tooth present in the midline between the two central incisors
What is hyperdontia?
rare condition where there are >32 teeth between the arches
What issues do tuberculate teeth cause?
tuberculate supernumaries tend not to erupt but prevent eruption of adjacent teeth, therefore, referral warranted often performed with incisor exposure