Year 3 (Clinical) Flashcards
Define Kennedy Class I
Bilateral free end saddles
Define Kennedy Class II
Unilateral free end saddle
Define Kennedy Class III
Bounded saddle
Define Kennedy Class IV
Bounded saddle that crosses the mid line
What are the components of a partial denture
- Saddles
- Rests
- Clasp
- Reciprocating component
- Major connector
What are the two types of clasp for partial denture and where are they used?
- Occlusally approaching clasp: molars
2. Gingivally approaching clasp: premolars and canines
How much gutta percha should be left apically for a post prep?
4mm
How much dentine should remain surrounding the post?
1mm dentine lateral to the post
Why are grooves incorporated into post preparation?
- To provide resistance (to the lateral forces subjected on the tooth daily)
- NOT mainly for retention
Where should post preparation be avoided?
- Upper first premolars (canine fossa leads to perforation)
- Oval shaped root of lower premolars causes circular para post to have low retention inside the canal (use custom post instead)
- Mesial root of lower molars
What are the uses of a facebow transfer?
- Allows suitable orientation of the occlusal plane
- Allows the maxillary cast to be mounted on the articulator in the correct anatomical position
- Transfers relationship of the maxilla and mandibular rotation points to the articulator
* Facebow has nothing to do with ICP or OVD
What are the different methods of recording impression for crowns and bridges?
- One stage impression (putty and wash recorded together)*
- Two staged unspaced (putty is recorded first and then relined with wash)
- Two staged spaced (putty is recorded with space allocated for wash)
a) Using polythene spacer
b) Recording putty impression before tooth preparation
c) Gouging away putty and providing escape channels for wash
* recommended as it is more accurate
Define combination syndrome
Dental condition seen in patients with completely edentulous maxilla and partially edentulous mandible with preserved anterior teeth
List features of combination syndrome
- Mandibular ridge resorption
- Flabby maxillary ridge
- Enlarged tuberosities
- Over erupted lower incisors
* try to avoid anterior guidance in combination syndrome
What are features of the Every denture?
- All connector borders are at least 3mm from gingival margins
- Open design of the saddle/tooth junction is employed
- Point contacts between artificial teeth and abutment teeth to reduce lateral stresses to a minimum
- Posterior wire stops are included to prevent distal drift of the posterior teeth (also contribute to bracing action posteriorly)
- Flanges are included to assist bracing of denture
- Lateral stresses are reduced by relying on guidance from remaining natural teeth to disclude the denture teeth on excursion
What is the act that governs the licensing, sale, supply, labelling and packaging of medicinal product?
The Medical Act of 1968
Under The Medical Act of 1968, what can a GDP prescribe under the NHS?
- General sales list medicines
- Pharmacy medicines
- Prescription only medicine
Under The Medical Act of 1968, what can’t a GDP prescribe under the NHS?
- Unlicensed medicine
2. Medical device
What are features of general sales list medicines?
- Sold or supplied other than the direction of a pharmacist
- Can be purchased at retail outlet
- Eg;
a) Ibuprofen
b) Chlorhexidane mouthwash
c) Fluoride toothpaste <1500ppm
What are the features of pharmacy medicines?
- Only from a pharmacy
- Under the direction of a pharmacist
- Can be sold over the counter without a prescription
- Can be prescribed by a dentist, doctor or recognised non-medical practitioner
- Eg;
a) Corsodyl dental gel
b) Flouride tablets
c) Miconazole oral gel
What are examples of prescription only medicines?
- All oral antibiotics
- Duraphat toothpaste or any toothpaste >1500ppm
- Aciclovir tablets
- Topical and systemic anti fungal
What is the act that regulates what dentist and doctors can sell to patient?
The NHS Act 1977
What are two basic features that a prescription form should have?
- Be signed by the prescriber
2. Be issued separately to each patient whom the clinic/contractor is providing services
What is the form used by a dentist to prescribe medicines?
FP10D
What are the medications that can be prescribed on a FP10D form?
Medicines listed in the Dental Practitioners Formulary
What is the act that governs the misuse of drugs?
The Misuse of Drugs Regulations 2001
Under The Misuse of Drugs Regulations 2001, which schedules of drugs can a dentist administer?
Schedule 2, 3, 4 or 5*
*any person may administer to another any drug under schedule 5
What is the significance of taking a drug history?
- Patient safety
- Diagnostic significance
- Effective and appropriate treatment
- Hidden medical history
What are the barriers of taking a patient drug history?
- Perceived relevance by patient
- Non prescription drugs
- Supplements, herbal remedies
In which circumstance is ICP used to record horizontal relationship?
When there is definite centric occlusion
In which circumstance is RCP used to record horizontal relationship?
When there is insufficient number of teeth present in the dentition
In which circumstance do you get a wax registration before taking a master impression?
When there is ICP present but not enough teeth to place the cast together by hand in ICP
How do you record ICP?
- Hand articulate the cast and check it with patients mouth
If not possible - Use a wax wafer and get patient to bite together
If not possible - Use wax occlusal rims + bite registration paste
Why do we survey a cast?
To determine
- Presence of undercuts
- Type of support
- Depth of undercut
- The contour of the undercut relative to gingival margin
- The path of insertion of the denture
What does a survey line indicate?
Marks the position of maximum convexity thus separating undercut from non undercut areas
What is the purpose of an undercut gauge?
Measures the extent of horizontal undercut
What are the sizes of undercut gauge available and what materials are associated with each size?
- 0.25mm: cobalt chromium
- 0.50mm: gold
- 0.75mm: stainless steel
How deep is a rest seat?
1mm in depth
What is the length needed for an occlusally approaching clasp to be effective?
At least 15mm
What are equipments commonly used in dental extraction?
- Coupland’s elevators
- Luxators
- Cryers
- Warwick James
- Forceps
What is the function of Coupland’s elevators?
To sever the periodontal membrane thus dilating the bony socket surrounding the tooth
How are Coupland’s elevators used?
- Used sequentially from 1 > 2 > 3
2. Uses rotational force directed perpendicular to the tooth
How do you use luxators?
- Used in the long axis of the tooth where it is pushed as far apically as possible
- Finger rest is applied on the shank (of the dominant hand)
- Finger and thumb support is applied on the alveolus
What variety of luxators are available?
- Straight
a) 3mm
b) 5mm - Curved
a) 3mm
b) 5mm
When are cryers and Warwick James usually used?
- Upper third molar
- Retained roots
- Removing inter septal bone
How do cryers differ from Warwick James?
Cryers have triangular pointed working end where as Warwick James have curved working end
For which tooth are forceps not recommend for?
Mandibular third molars
Describe the primary/preliminary movement of tooth extraction
Purpose: 1. Sever periodontal membrane 2. Generally dilate the socket Method: 1. Force directed along long axis of the tooth 2. Blade of forceps towards root apex
Describe the secondary movement of tooth extraction
Purpose: 1. Complete dilation 2. Withdrawal of tooth Method: 1. Depends on tooth root and morphology (usually buccal a) Incisors, canines & lower premolars (single rooted): rotational movement b) Upper premolars: buccal movement c) Molars: buccal or figure of 8
Where should the operator stand for extraction of lower right tooth?
Behind the patient (on the right)
Where should the operator stand for extraction of lower left tooth?
In front of the patient (on the left)
Where should the operator stand for extraction of upper tooth?
In front of the patient with the patients head at shoulder height (when standing straight) and arms straight with forceps
What are the pink consent forms used for?
Local anaethesia
What are the yellow consent form used for?
Sedation/GA
What are five aspects of clinical record that must be present before you can proceed with an extraction?
- Written diagnosis and treatment plan stating which tooth is to be extracted
- Periapical radiograph of the tooth
- A completed consent form
- A contemporaneous medical history
- A correct site surgery form
List 12 items that must be written in the clinical notes for the extraction appointment.
- The procedure that was carried out
- If medical history was checked at the beginning of the appointment
- If any glucose drink was given or medications taken
- The local anaesthetic administered (LA agent, batch number, expiry date, amount give, type of injection)
- How the treatment was carried out
- If any complications occurred
- If closure was required
- If haemostasis was achieved
- Post operative instructions were give
- Any antibiotics/analgesics given
- Signed and dated by student and tutor
- Completed correct site surgery form
What does minor oral surgery comprise of?
- Removal of teeth/roots surgically
- Treatment of bony pathology
- Exposure of ectopic teeth
- Soft tissue surgery (biopsy)
- Closure of defects
When do we consider surgical approach?
- When conventional approach is unsuccessful
- Decoronated tooth
- Impacted teeth
Why do we raise a flap?
- For visualisation purposes
- Protects vital structures
- To allow a clean closure
State the principles of flap design
- The flap is broader at the base to prevent loss of perfusion
- Include the papilla
- Ensure that margins are on sound bone
- Avoid tearing the flap
- Ensure flap is broad enough to give adequate access to what you are doing
- Avoid important anatomical structure
What are the important anatomical structures to avoid when designing a flap?
- Mental nerve
- Lingual nerve
- Nasopalatine & greater palatine nerves/vessels
What are the factors that makes accessing a tooth for extraction difficult?
- Orientation of the tooth
- Existing caries/restorations: weakens the tooth
- Root canal treatment: weakens the tooth
- Patients age: younger bone has more elasticity
- Bone quality: the denser the bone the harder the extraction
- Root anatomy: curved roots are hard to extract
- Proximity to structures
What is the instrument used to raise a flap?
Howarth’s elevator is used to raise flap and protect vital structure
What is the use of a Mitchell’s osteo trimmer?
Remove granulation tissue in tooth socket
What are the uses of bitewing radiography?
- The detection of dental carries in the upper and lower premolars and molars
- Monitoring the progression of dental caries
- The assessment of existing restoration
- The assessment of periodontal condition (secondary use)
What are the teeth included in a bitewing?
Premolars, molars and distal of canine
How does a bitewing change when a patient has erupted third molars (long dental arch)?
Two bitewings per side are taken:
- Premolars bitewings
- Molar bitewings
When are vertical bitewings indicated?
- BPE score of 4 or *
2. Other BPE score with significant gingival recession
Why is radiography useful for caries diagnosis?
- Reveals more lesion than clinical examination alone
- Allows us to see areas inaccessible to direct vision
- Allows us to estimate depth and extent of caries
- Allows us to monitor progression/regression of caries over time
List types of caries
- Proximal
- Occlusal
- Smooth surface
- Root
- Recurrent
State the classification of proximal caries
D1: outer enamel D2: inner enamel D3: outer dentine D4: inner dentine D5: pulpal involvement
What is the best way to detect occlusal caries?
Direct vision of a dry tooth
When do you restore a tooth with caries?
When the lesion has causes a cavitation. Temporary tooth separation could be used to help check cavitation
What is the earliest stage of occlusal caries detected on a radiograph?
D3 (D1 and D2 occlusal caries will never be detected on a radiograph)
What is a Mach Band effect?
Edge enhancement effect produced in the brain which leads to false positives
What is the earliest stage of root caries?
D3 as there are no enamel on the root surface
Where should the crestal bone be in relation to the cemento-enamel junction?
0.5-1.9mm
How do you measure bone loss on a radiograph?
Bone loss: (Distance from CEJ to bone level) - (2mm)
What are early signs on bone loss on a radiograph?
- Loss of cortical density
- Rounding off of junction between alveolar crest and lamina dura
- Blunting of crest
How do you classify bone loss?
Mild: 1-2mm
Moderate: 3-4mm
Severe: >5mm
What are the 3 things that should be noted in a radiographic report?
- Periodontal bone and calculus
- Proximal surface caries
- Occlusal caries
- Other findings (cyst, torus, retained roots, Turner’s hypoplasia)
List the essential image characteristics of a bitewing radiograph
- No evidence of bending of the image of the teeth
- No foreshortening or elongation of the teeth
- Ideally no horizontal overlap (if present should not obscure more than half of enamel thickness)
- Should cover distal surface of the canine and mesial surface of the most posterior erupted teeth
- The periodontal bone level should be visible and equally imaged in the maxilla/mandible
- There should be good density and contrast between enamel and dentine
How often should bitewings be taken for permanent dentition?
High risk: 6 months
Moderate risk: 12 months
Low risk: 24 months
How often should bitewings be taken for primary dentition?
Low risk: 6 months
Moderate risk: 12 months
High risk: 12-18 months
List treatment options for free end saddles
- Shortened dental arch
- Distal cantilever bridges
- Removable partial denture
- Implant supported/retained prosthesis
When is an acrylic free end saddle usually indicated?
As a transitional denture
What is the negative consequence of acrylic denture?
As they rely on mucosal support to retain the denture, they act as gum strippers and thus damage the gingival tissues
How do you stop adverse loading of the free end saddles on the ridge?
To cover as much of the denture bearing area as possible:
- Cover the retro molar pad area
- Extend into the lingual sulcus
How is support provided in CoCr free end saddle denture?
Combination of tooth support and mucosa support:
- Tooth support from anterior aspect of saddle
- Mucosal support posteriorly
What is the general rule of rest seat specific to free end saddles?
The rest seat MUST always be placed on the mesial aspect of the abutment teeth to ensure even distribution of load
What are the two approach to prevent denture rotation in displaceable mandibular tissues?
- Rigid connector between mucosa and tooth supported parts of the denture (most favoured approach)
- Flexible major connected that allows mucosal supported parts to move independently of the tooth supported parts
What is the technique used when designing a rigid connection?
Altered cast technique
Describe the altered cast technique
- CoCr framework carries an acrylic special tray that covers the saddles
- A mucodisplacive impression of the saddle is taken using ZnOE
- The free end saddle part of the old cast is cut off
- A new cast is made incorporating the old cast and the mucodisplacive impression of the free end saddle
- A new denture is fabricated based on the altered cast
- The resulting lower denture should resist tissue displacement when load is applied to the denture
Give example of a stress breaker design
Split lingual plate
State the essential factors when designing a free end saddle
- Denture teeth should lie on the ridge
- Ensure maximum denture extension: halfway up the retro molar pad
- Ensure even occlusal contact in retruded contact position
- Reduce size of occlusal table (Eg: not including 7s)
- Keep clasps flexible (wrought stainless steel wire)
What are the advantages of using a rigid connector instead of flexible connectors?
- Simplicity of the design
- Simplified technical procedures
- Gives more control over applied load
- Flexible connectors (stress breakers) give poorer lateral stability
- Flexible connectors are more likely to cause soft tissue entrapment and lead to fracture of the denture
Which component of the free end saddle provides indirect support?
Clasps that resists denture rotation that occurs at the rests (after the rests have resist rotation of the clasp)
Which component of the free end saddle provides indirect retention?
- Anterior rests
- Continuous clasp
- Anterior palatal bars
- Lingual plates
How is indirect retention provided in a free end saddle?
- When a patient bites into a toffee and separate their teeth, the denture will rotate away from the saddle areas
- Thus the denture will rotate around the clasp as the clasp tries to resists displacement of the denture
- That rotation is that resisted by any rests or connector anterior to the clasp (anterior to that axis of rotation)
- This causes the denture to move downwards toward the tissue again
What are the two other options for treating a free end saddle?
- Bridges (but can lead to overloading on abutment teeth)
2. Implants (consider available bone, surgical morbidity and cost)
What makes the Every denture hygienic?
- Mucosa-borne only
- Has no clasp or rest
- Retained by frictional contact of the Every denture with natural teeth
How does the Every denture prevent gingival trauma?
Lack of marginal coverage
Are distal stabilisers in an Every denture clasps?
No. They are there to improve bracing action of the denture
When do we use an Every denture?
To restore multiple bounded edentulous area in the maxillary jaw
What are other design of acrylic denture?
- Spoon denture
- T shape denture
* although provided minimum gingival coverage there is a potential hazard of inhalation or ingestion
What are indications of providing an acrylic denture?
- Interim denture before a definitive treatment plan can be formulated
- The remaining teeth have poor prognosis and their extraction and subsequent addition to the denture is anticipated
- An immediate denture replacing anterior teeth
* it is never a permanent solution in the lower arch
What are the disadvantages of acrylic denture?
- No rests so they rely on tissue support
- Limited support provided by tissue as teeth can resist vertical loading much better than mucosa
- Acrylic denture requires maintenance
What are limitations to the Every denture?
- Prone to fracture
- Maximal coverage of palatal tissues
- Excessive adjustment on denture insertion leads to loss of retention
What is the function of the RPI system?
To avoid damaging the distal abutment tooth in a free end saddle
What are features of a cast cobalt chromium clasp?
- Needs to be 15mm in length to avoid permanent deformation in an undercut of 0.25mm
- Use only with molar teeth
- If undercut does not exist it should be created with composite resin
- Only the terminal third engages the undercut
What are features of wrought stainless steel clasp?
- Should engage an undercut of 0.75mm
- Should be 7mm or more
- Occlusally approaching clasp could be used in premolars or canine region
What are two of the most common cast cobalt chrome lingual connector?
- Lingual bar
2. Lingual plate
Which situation contraindicates a gingival approaching clasp?
A large tissue undercut because it must be spaced well away from the ridge and inevitably rubs against the cheeks
When do you record BPE?
- For all new patients
2. For patient with codes 0, 1 or 2 BPE should be recorded annually
What is the subsequent step when a BPE code 3 is obtained?
- DPC for that sextant
2. BPE for all other sextants with 0,1 and 2
What is the subsequent step when a BPE code 4 is obtained?
- DPC through out the entire dentition
Can BPE be used to assess response to periodontal therapy? Justify.
- No
- It does not provide information about how sites within a sextant change after treatment
- Instead probing depth should be recorded at 6 sites per tooth
How often should patients with BPE code 3 and 4 (pre treatment) have their pocket depths measured (post treatment)?
At least annually
Which BPE codes are radiographs (to assess alveolar bone level) indicated for?
Codes 3 and 4
What are the 3 factors to consider in your periodontal patient before arriving at the diagnosis?
- Medical condition/diseases of the patient
a) History and exam
b) Special test or lab test
c) Medical consultation - How severe is the bone loss
a) Mild: 1-2mm
b) Moderate: 3-4mm
c) Severe: >5mm - Localised or generalised
a) Localised: 30%
List the main clinical features of chronic periodontitis
- Most prevalent in adults but can occur in children and adolescents
- Amount of destruction is consistent with presence of local factors
- Subgingival calculus is frequent finding
- Associated with variable microbial pattern
- Slow to moderate rate of progression but may have period of rapid progression
- Can be associated with local predisposing factor (tooth related or iatrogenic)
- May be modified and/or associated with systemic diseases
- Can be modified by other factors other than systemic disease (smoking and emotional stress)
List the primary and secondary clinical feature of aggressive periodontitis
Primary
1. Except for periodontitis, patients are otherwise clinically healthy
2. Rapid attachment loss and bone destruction
3. Familial aggregation
Secondary
1. Amounts of microbial are inconsistent with severity of periodontal tissue destruction
2. Elevated proportions of
a) Actinobacillus actinomycetemcomitans
b) Porphyromonas gingivalis (in some populations)
3. Phagocyte abnormality
4. Hyperesponsive macrophage phenotype (prostaglandin E2 and interleukin 1Beta)
What are specific features of localised aggressive periodontitis?
- Circumpubertal onset
- Robust serum antibody to infecting agent
- Localised first molar/incisor presentation
What are specific features of generalised aggressive periodontitis?
- Usually affecting person under the age of 30 but patients may be older
- Poor serum antibody response to infecting agent
- Pronounced episodic nature of destruction of attachment and alveolar bone
- Generalised attachment loss affecting at least 3 permanent teeth other than first molars and incisors
What are the aims of non surgical periodontal therapy?
- Removal of attached biofilm and non attached microflora in the gingival sulcus and periodontal pocket
- Removal of plaque retentive factors (calculus, overhanging restoration and areas of cementum hypoplasia and resorption)
- Rendering the root surface as smooth as possible
How is recurrent infection of the periodontal pocket prevented?
- Meticulous gingival plaque control via
a) Daily oral hygiene
b) Professional mechanical tooth cleaning - Address local risk factors
- Minimise the effect of systemic risk factors
- Alteration or elimination of putative periodontal pathogen
What are some of the reason patients fail to comply with oral hygiene advice?
- Unwillingness to perform self oral care
- Poor understanding of the recommendation
- Lack of motivation
- Poor dental health beliefs
- Stressful life events
- Low socio economic status
List ideal feature of a toothbrush
- Handle size appropriate to age and dexterity
- Head size appropriate to the size of patients mouth
- Round ended nylon or polyester filaments not larger than 0.009” in diameter
- Soft bristle configuration as defined by ISO
- Bristle pattern that enhances plaque removal approximally and at the gingival margin
List the active ingredients of toothpaste
- Fluoride
- Antibacterial agent (triclosan)
- Desensitising agent (potassium nitrate, strontium)
- Anti tartar agent (pyrophosphates)
- Sodium bicarbonate
- Enzymes (increases antibacterial properties of saliva)
- Xylitol (reduces level of cariogenic bacteria in the mouth)
List the inactive ingredients in toothpaste
- Water
- Detergent
- Binding agents
- Humectants (to retain moisture)
- Flavouring
- Preservative
- Abrasives (silica or powdered calcium salts)
What are interproximal cleaning aids available?
- Floss
- Wooden sticks
- Brushes
- Bottle brushes
What are indications of root surface debridement?
- Highly motivated patient who has achieved a high standard of supra and subgingival plaque control but still has evidence of active disease
- Pockets with active disease (pocket >5mm which bleeds on probing)
- The presence of detectable sub gingival deposits in a risk patient (aggressive cases) despite an a science of overt clinical signs of inflammation
What are contraindications of root surface debridement?
- Poorly motivated patient who does not demonstrate high standard of supra and subgingival plaque control
- Patients with high INR
- The absence of BOP from a deep but stable pocket
List root surface debridement protocols
- Confirm sites requiring root surface debridement
- Administer LA
- Patients rinse with 0.2% chlorhexidane mouthwash for 60s
- Carefully probe sites to identify deposits
- Use ultrasonic hand piece
- Use site specific curettes
- Recheck with complete removal of deposits with probe
- Re-instrument and irrigate using ultrasonic scaler
- Post operative instructions
List Gracey protocols
- Select correct instrument to site
- Identify working end
- Insert passively and parallel to long axis of root
- Ensure good finger rest
- Ensure correct operator/patient position
- Turn toe to engage root surface
- Excuse the following strokes:
a) Vertical strokes
b) Oblique strokes
c) Horizontal strokes
How long should the revaluation be after a non surgical periodontal treatment?
3 to 6 months
