Impression techniques and soft tissue management Flashcards
β What are the principles of managing periodontal tissue when planning extra-coronal restorations?
Establish periodontal health for clinical success πͺ
Design restorations to allow for plaque control π¦·π§Ό
Avoid iatrogenic damage π«π
Why must gingiva be healthy before starting extra-coronal restorations?
Proves patient motivation π‘
Stabilizes gingival margins β
Facilitates easier preparation & impression taking ποΈ
Inflamed gingiva bleeds easily on touch π©Έ
Swollen gingiva hinders access π·
Poor oral hygiene β‘οΈ gingival recession β‘οΈ visible crown margins π¬
How can you establish gingival health before restorations?
Oral hygiene instruction (OHI) and patient motivation πͺ₯π¬
Remove plaque-retentive factors (PRFs) π§½
Remove calculus and overhanging restorations π¦·
Provide temporary crowns (chairside/lab-made) π
No bleeding on probing or marginal bleeding π«π©Έ
How should a restoration be designed to promote gingival health?
Facilitate plaque removal and discourage accumulation π§Ό
Consider margin position π
Material selection πͺ¨
Embrasure spaces and contour π―
What are the 3 types of margin positions?
Subgingival β¬οΈ
Juxta-/Equigingival π°
Supragingival β¬οΈ
When would a subgingival margin be indicated?
Caries extends into gingival crevice π¦
Need for increased retention π
Existing restoration is already subgingival π
Dentinal hypersensitivity π§π¦·
Aesthetic demands (patient or dentist) π
Subgingival fracture of the tooth π¬
How can you minimise the negative effects of subgingival margins?
Optimal gingival health beforehand π¦·πΏ
Minimal gingival trauma β
Gentle retraction cord use π§΅
Take sulcus impression immediately after cord removal π©Ή
Use well-fitting, properly contoured provisionals π
Observe oral hygiene post-placement ππͺ₯
Why is restoration contour critical for gingival health?
Must allow for optimum plaque control π§Ό
Excessive bulk in gingival third β plaque buildup π«
Excess contour does not protect gingiva
Precision tooth prep is essential for proper contour βοΈ
β What is the aim of a master impression?
To capture an accurate, dimensionally stable, and fully supported impression of the prepared teeth and soft tissues π―π¦·
What factors influence a successful impression?
Right impression tray πͺ£
Proper choice & handling of materials π§ͺ
Field control π
Patient management π
Accurate impression assessment π
Labelling, disinfection, transport & storage π§Όπ¦
Accurate impression casting π§
What is required when capturing a subgingival margin in impressions?
Clear visibility of entire margin ποΈ
Subgingival margins = require soft tissue management π§΅π©Έ
What are the methods of soft tissue management for impressions?
Retraction: Cord or retraction paste π§΅π§΄
Removal: Rotary curettage, electrosurgery, or laser π¨π¬
Bleeding control: Haemostatic agents π§ͺ
What are the advantages and disadvantages of retraction cords?
Advantages:
Universal technique π
Varying degrees of retraction possible π
Inexpensive π·
Single/double cord techniques π―
Disadvantages:
Can cause bleeding π©Έ
Painful for the patient π£
Time-consuming β³
Risk of recession if epithelial attachment is damaged β οΈ
What precautions should be taken with retraction cord use?
Cords have colour/number codes for size identification π¨π’
Healing occurs within days if epithelial attachment is severed carefully π οΈ
Longer cord time = higher chance of adverse effects π
Removing dry cord can tear epithelium β‘οΈ recession π¬
Always document cord removal β
π
How is bleeding controlled during impressions?
Haemostatic agents π§ͺ
Pressure from cord/putty π§΅
Electrocautery β‘
Compare different haemostatic agents:
Aluminium chloride (pH 3) β least reactive with impression materials π‘
Ferric sulphate (1.2%) β stains tissue black, may inhibit impression set π€
Aluminium sulphate (pH 3) β offensive taste π
Adrenaline (pH 7) β hard to dose, can increase heart rate πβ οΈ
What is a retraction paste, and how is it used?
Injectable paste for sulcus retraction π
Keeps field dry βοΈ
Often contains aluminium chloride to control bleeding π§ͺ
Applied for 1β2 mins then rinsed away πΏ
What are the pros & cons of electrosurgery for soft tissue removal?
Pros:
Great haemostasis if tissue isnβt inflamed π©Έ
Cons:
Risk of gingival recession π·
Contraindicated for pacemaker users β οΈ
Cannot use plastic instruments π§΄
How do you assess an impression effectively?
Start with full view, then zoom in π
Dry it and use good lighting π‘
Check for:
All teeth in the arch π¦·
Tray showing through? β
Air blows that affect articulation? π¨
Material stuck to tray? π§½
Prep margins all visible? π§
No drags or voids π«
Adjacent/contralateral teeth visible? β
Which parts of the restoration process can affect gingival health?
Provisional restoration ποΈ
Final restoration and its design π§±
Cementation technique and material π§ͺπ§½
How do provisional restorations impact gingiva?
Poor fit = plaque retention hotspot π¦
Should be used for the shortest time β³
Marginal finish & polish are crucial β¨
Why is the fit of a crown critical?
Poor fit = periodontal disease risk π§«
Defective margins linked with alveolar bone height reduction π
How does surface smoothness affect tissue response?
Roughness aids plaque build-up π¬
Highly polished gold works well β¨
Gingiva prefers ceramic πͺ¨
Composite resin = more issues π«
How should margins be finished for optimal gingival health?
Even experienced clinicians can miss 120ΞΌm gaps π
Aim for the thinnest cement layer possible π
Ensure proper taper and eliminate irregularities π―
What are the best practices for cementation?
Do not overfill the crown with cement π«
Apply using microbrush for control π―
Be aware of working and setting times β±οΈ
Check sulcus thoroughly for excess cement π
Use knotted floss to remove cement interproximally π§΅
FINAL KEY POINTS SUMMARY:
β
Start with optimal gingival health π±
Supragingival margins are ideal π
If subgingival margins are needed, prepare with care π§΅π οΈ
Impressions rely on excellent soft tissue management π―
Maintain gingival health during temporisation π
Smooth marginal interfaces = better tissue response β¨
Always remove excess luting cement! π§½
