Clinical Problem Solving In Dentistry

Question 0

A 17 year old presents at your general dental surgery with several caurious lesions, one of which is very large. How should you stabilise his condition?
C/O, HPC, MH, E/O, I/O taken, what further examination would you carry out?
What radiographs would you take? Explain why each view is required.

Answer 0

Test vitality of deep carious teeth and adjacent teeth to rule out of diagnosis.
BWs to detect approximal surface caries, and occlusal caries. PA of deep carious/pulpally involved teeth. OPT might be useful as a general survey view in a new pt and to determine presence/position of 3rd molars.

Question 1

What is the predominant form of caries in adolescents? Give two reasons why may you this go undetected (3)

Answer 1

• Occlusal lesions
  1) Starts on the fissure walls and is obscured by sound superficial enamel
  2) Lesions cavitate late, if at all, probably because fluoride strengthens the overlying enamel. Superimposition of sound enamel also masks small and medium sized lesions on bite wing radiographs.

Question 2

What does occlusal caries in the second molars suggest? (1)

Answer 2

• Arouses suspicion that other pits and fissures in the molars will be carious.

Question 3

If two or more teeth were possible causes of a draining sinus, how might you decide which was the cause? (3)

Answer 3

• Gutta percha point could be inserted into the sinus prior to taking the radiograph.
• Medium or fine sized point is flexible but still resilient enough to pass along the sinus tract if twisted slightly on insertion.
• Points are radiopaque and can be seen on a radiograph extending to the source of an infection

Question 4

In sequence of treatment, what is the immediate phase? Give reasons.

Answer 4

• Caries removal and extipation or XLA of painful pupally involved teeth plus drainage of abscesses/sinuses
• Reason: get patient out of pain, extipation and dressing is essential if tooth is to be saved and to remove source of apical infection, urgent need to minimise further destruction of tooth before it is rendered unrestorable.

Question 5

What is the stabilisation stage of treatment? When should this happen? (3)

Answer 5

• Stabilisation of caries should be second, after getting the patient out of pain in the immediate phase
• Stabilisation of caries should be carried out by removing caries from teeth and dressing with temporary restorations (GIC), visits to be done per quadrant if caries is extensive
• Reason: to prevent further tooth destruction and progression to carious exposure while other phases of treatment are being carried out

Question 6

What is the preventive treatment phase, when should this occur? Give reasons.(3)

Answer 6

• Dietary analysis, OHI, fluoride advice/supplements
• Should be the third phase, after immediate and stabilisation
• Reason: should start immediately and extend throughut the treatment plan, to reduce the high caries rate and ensure the long-term future of the dentition

Question 7

What does the permanent restoration phase of treatment depend on? Give reasons (2)

Answer 7

• Will depend on what is found while placing temporary restorations
• Permanent restorations may be left until last; stabilisation takes priority

Question 8

What are the properties of Zinc Oxide and Eugenol pastes when used as a temporary filling material? Give an example, what situations can this be used in? (5,2)

Answer 8

• • Bactericidal
• • Easy to mix and place
• • Cheap
• • Not very strong
• • Easily removed
• Kalzinol
• Suitable temporary restoration of most cavities povided there is no significant occlusal load. Endodontic access cavities

Question 9

What are the properties of self-setting zinc oxide cements when used as a temporary material? Give two brand examples, in what situations is this material useful? (2,2,2)

Answer 9

• Harden in contact with saliva
• Reasonable strength and easily removed
• Cavit
• Coltosol
• Endodontic access cavities
• No occlusal load

Question 10

What are the properties of polycarboxylate cements when used as a temporary material? Give a brand example, in what situations is this material useful? (2,1,2)

Answer 10

• Adhesive to enamel and dentine
• Hard and durable
• Poly-F
• Used when mechanical retention is poor
• Strong enough to enable rubber dam placement when used in a badly down tooth

Question 11

What are the properties of glass ionomer, including silver reenforced preparations, when used as a temporary material? Give a brand example, in what situations is this material useful? (5)

Answer 11

• Adhesive to enamel and dentine
• Hard and durable
• Chem-fil, Ketac Silver
• Used as polycarboxylate cements and also useful in anterior teeth

Question 12

What is the most important preventative procedure in a patient with high caries rate? How does this affect caries? What is a further advantage of this? (5)

Answer 12

• Diet analysis
• Caries requires dietary sugars, in particular sucrose, glucose and fructose, an acidogenic plaque flora and a susceptible tooth surface.
• Denying the plaque flora its substrate sugar is the most effective measure to halt the progression of existing lesions and prevent new ones forming
• No preventive measure affecting the flora or tooth is as effective
• A further advantage of emphasis on diet is that is forces patient to acknowledge that they must take responsibility for preventing their own disease

Question 13

How would you evaluate a patient’s diet? (3)

Answer 13

• Dietary analysis consists of two elements: enquiry into lifestyle and into the dietary components themselves.
• Information about the diet itself is of little value unless it is taken in context with the patient’s lifestyle
• Only dietary recommendations tailored to the patient’s lifestyle are likely to be adopted

Question 14

How would you analyse a patient’s diet sheet? (5)

Answer 14

• Highlight sugar-rich foods and drinks
• Note whether they are confined to meal times or whether they are eaten frequently and spaced throughout the day as snacks
• The number of sugar attacks should be counted and discussed with the patient
• Also note the consistency of the food because dry and sticky foods take longer to be cleared from the mouth
• Sugared drinks immediately before bed are highly significant because salivary flow is reduced during sleep so clearance time is greater

Question 15

What are the aims of Dietary Advice? (3)

Answer 15

• Reduce the amount of sugar
• Restrict frequency of sugar intakes to meal times as far as possible
• Speed clearance of sugars from the mouth

Question 16

What is the method for Reducing the Amount of Sugar in a Patient’s diet? (6)

Answer 16

• Ask patient to check the manufacturers’ labels and avoid foods with sugars such as sucrose, glucose and fructose listed early in the ingredients
• Natural sugars (e.g. honey, brown sugar) are as cariogenic as purified or added sugars.
• When sweet foods are required, choose those containing sweetening agents such as saccharin, acesulfame-K and aspartame
• Diet formulations contain less sugar than their standard counterparts but check labels
• Reduce the sweetness of drinks and foods
• Become accustomed to a less sweet diet overall

Question 17

What is the method for Restricting the Frequency of Sugar Intakes to Meal Times as far as possible? (3)

Answer 17

• Try to reduce snacking
• When snacks are required select ‘safe snacks’ such as cheese, crisps, fruit or sugar-free sweets such as mints or chewing gum (which not only has no sugar but stimulates salivary flow and increases plaque pH)
• Use artificial sweeteners in drinks taken between meals

Question 18

What is the method for Speed Clearance of Sugars from the Mouth? (2)

Answer 18

• Never finish meals with a sugary food or drink

- Follow sugary foods with a sugar-free drink, chewing gum or a protective food such as cheese

Question 19

After RCT, when would complete bony/dental healing be expected? What can then be judged? (2)

Answer 19

• 6months to 1year

- Success of RCT can then be judged

Question 20

What is a diagnosis of red spots on the tongue in normal anatomy? When and why can these appear more prominent? (2)

Answer 20

• Fungiform papillae

- Can appear more prominent when the tongue is furred, for instance when the diet is not very abrasive

Question 21

C/O - LRQ posterior teeth are loose, jaw on RHS feels enlarged.
HPC - Teeth slowly became loose over 6months
C/E - presents with bony, hard enlargement on the buccal and lingual aspects of the RHS mandible. Deep cervical lymph nodes are palpable on the RHS, they are only slightly enlarged, soft, not tender and freely mobile.
On the basis of what you know so far, what types of condition would you consider to be present here?

Answer 21

• History suggests relatively slow growing lesion
• Likely to be benign
• Common jaw lesions which cause expansion are odontogenic cysts.
• Commonest odontogenic cysts are radicular (apical inflammatory) cyst, dentigerous cyst and odontogenic keratocyst

Question 22

Whilst not a definitive relationship, what specific features can suggest malignancy? What commonly associated feature is not necessarily suggestive of malignancy? (5,1)

Answer 22

• Perforation of cortex
• Soft tissue mass
• Ulceration of the mucosa, unhealing
• Numbness of the lip
• Devitalisation of the teeth
• The character of the lymph node enlargement does not suggest malignancy

Question 23

What radiographs would be indicated for investigating lesions causing expansion of the jaws? Why? (8)

Answer 23

• OPT or an Oblique Lateral
• To show the lesion from the lateral aspect. Oblique lateral would provide the better resolution but might not cover the anterior extent of this large lesion. OPT would provide a useful survey of the rest of the jaws but only that part of this expansile lesion in the line of the arch will be in focus.
• Posterior-anterior (PA) of the jaws
• To show the extent of mediolateral expansion of the posterior body, angle or ramus
• A lower true (90degree) occlusal
• To show the lingual expansion which will not be visible in the PA jaws view because of superimposition of the anterior body of the mandible
• A periapical of the lower right second premolar and the first molar
• To assess bone support and possible root resorption

Question 24

Why might, in a pt with RHS mandible expansion, roots of e.g. first molar, second premolar appear to be so resorbed in the periapical view when the oblique lateral views shows minimal root resorption? (2,3)

Answer 24

• The teeth are foreshortened because they lieat an angle to the film.
• Film has been taken using the bisected angle technique and several factors contribute to the distortion
• -The teeth may have been distorted by a lesion, so the crowns lie more lingually, and the roots more buccally
• • Lingual expansion of the jaw makes film packet placement difficult, so could have had to be severely angulated away from root apices
• • Failure to take account of these two factors when positioning and angling the x-ray tubehead

Question 25

Describe the expected appearance, radiographically, of an Ameloblastoma (3,4)

Answer 25

• Classically produces an expansile multilocular radiolucency at the angle of the mandible
• Most commonly presents in 4th/5th decade
• More common in African ethnicity
• Radiographically appears:
• • Multilocular radiolucency, containing several large cystic spaces seperated by bony septa
• • Root resorption
• • Tooth displacement
• • Marked expansion

Question 26

At what age can a Giant Cell Lesion arise? How does this relate to its radiological features? (1)

Answer 26

• Can arise at almost any age but the radiological features and site are slightly different

Question 27

Describe typical features of a Central Giant Cell Granuloma (6)

Answer 27

• Expansile
• Sometimes multilocular
• Radiolucency, but can appear less radiolucent because it consists of solid tissue rather than cystic neoplasm
• Often containing wispy osteoid or fine bone septa subdividing the lesion into a honeycomb-like pattern
• However, these typical features are not always seen
• The spectrum of radiological appearances ranges from lesions which mimic odontogenic and solitary bone cysts to those which appear identical to ameloblastoma or other odontogenic tumours
• No root resorption

Question 28

What is the aneurysmal bone cyst in relation to a central giant cell granuloma? (3)

Answer 28

• A giant cell lesion which can also produce a honey-comb pattern with prominent expansion
• Adjacent teeth are usually displaced but rarely resorbed
• Aneurysmal bone cyst is much rarer than central giant cell granuloma

Question 29

How would you differentiate an ameloblastoma from a giant cell granuloma for a definitive diagnosis? How should each be treated? (3)

Answer 29

• Biopsy is required for definitive diagnosis
• Ameloblastoma is treated with full excision
• Giant cell granuloma is treated with curettage

Question 30

For what diagnoses of different cysts/odontogenic tumours is an aspiration biopsy required and why? When is it not required? (3)

Answer 30

• If odontogenic keratocyst is suspected, this diagnosis might be confirmed by aspirating keratin
• Useful to decide whether a lesion is solid or cystic
• Not particularly helpful in the diagnosis of ameloblastoma

Question 31

Describe the typical and diagnostic histological appearances of an Ameloblastoma, including what the specimen would be stained with. (8)

Answer 31

• Specimen would be stained with haematoxylin and eosin (purple)
• At low power the lesion is seen to consist of islands of epithelium separated by thin pink collagenous bands
• Each island has a prominent outer layer of basal cells, a paler zone within that, and sometimes a pink keratinized zone of cells centrally
• These islands can show early cyst formation
• At higher power, the outer basal cell layer is seen to comprise elongated palisaded cells with reversed nuclear polarity (nuclei placed away from the basement membrane)
• Towards the basement membrane many of the cells have a clear cytoplasmic zone and the overall appearance looks like piano keys
• Above the basal cell layer is a zone of very loosely packed stellate cells with large spaces between them
• There is no inflammation