Extra coronal restorations: treatment planning Flashcards
What is an extra-coronal restoration?
A restoration placed on the external surface of a tooth 🦷, typically indirect (e.g., crowns 👑, onlays), used to restore function, aesthetics 💅, and protection 🛡️
They’re used to:
✅ Restore function (e.g. chewing)
✅ Improve aesthetics (colour/shape)
✅ Protect weakened or root-filled teeth 🛡️
What are the 4 main factors affecting success of an indirect restoration?
1️⃣ Patient factors – health, hygiene, preferences, finance
2️⃣ Tooth factors – amount and condition of remaining tooth
3️⃣ Material factors – bonding system, crown material
4️⃣ Operator factors – clinician skill and technique 🧑⚕️
All four must be carefully balanced for a successful outcome 💯✨
What are key patient factors in crown treatment planning?
🪥 Oral hygiene & dietary habits – Poor hygiene = higher failure risk
💺 Ability to tolerate treatment – Some patients may need multiple visits
💧 Moisture control – Important for bonding, esp. resin-based cements
💸 Aesthetic desires & economic status – Impacts material choice (e.g. ACC vs metal)
😬 Parafunctional habits – Bruxism can affect longevity and material selection
🗓️ Time availability – Indirect restorations require more appointmen
What tooth-related factors must be assessed before placing a crown?
🦷 Remaining tooth structure – Enough for retention?
🧫 Vitality & endodontic status – Is it vital? If not, has RCT been done well?
🧱 Core presence and material – Core build-up essential for strength
🦷 Tooth height – Is there sufficient height after prep?
📍 Tooth position in the arch – Posterior = strength, Anterior = aesthetics
🦷💥 Occlusion & parafunction – Opposing forces affect crown material
🏗️ Retention and resistance form – Ensures crown stays on long term
🚫 Absence of caries or periodontal disease – Must treat before crowning
🧴 Bleaching history – Recently bleached teeth may not bond well
Why must a periapical radiograph (PA) be taken before crowning?
📸 To assess:
🧱 Bone support – Is the tooth stable?
❌ Periapical pathology – Infection must be treated first
🪄 Root canal treatment – Is the obturation adequate?
🔍 Root morphology – Helpful for prep design and ferrule planning
Why is coronal tooth height crucial in crown prep?
📉 Crown prep reduces height – need enough remaining height to provide:
🧲 Retention – Keeps crown in place
🧱 Resistance – Prevents tipping or rotation
If height is insufficient → consider surgical crown lengthening or orthodontic extrusion 🧰🦷
What materials are suitable for core build-up? Which should be avoided?
✅ Composite resin – Good bond strength and aesthetics
✅ Bonded amalgam – Strong and durable, esp. for posterior teeth
❌ GIC – Avoid due to weak mechanical properties ❌🧪
What steps must be taken before placing a crown on a compromised tooth?
✅ Caries removal 🦠
✅ Periodontal therapy if needed 🦷🪥
✅ Root canal treatment if pulp is affected
✅ Core build-up using composite or bonded amalgam
✅ Tooth prep for crown – conservative yet adequate
List all uses of crowns 👑
✨ Restore broken-down teeth – Post-trauma or heavy wear
💅 Improve aesthetics – For discoloured, misshapen, or worn teeth
🛡️ Protect remaining tooth tissue – Esp. post-RCT
🔁 Replace defective onlays/crowns
🌉 Part of conventional bridgework – As abutments
🦷🪑 Support partial dentures – Rest seats can be added to MCC crowns
Can crowns maintain tooth vitality?
❌ No. Crowns do not help maintain vitality. In fact, they may risk it:
🧬 Up to 20% of crowned teeth become non-vital
🔬 8% may require RCT within 10 years
➡️ Biological cost must always be weighed ⚖️
What are the biological and financial costs of crowns?
🧬 Biological costs:
Tooth prep removes significant enamel/dentine
Risk to pulp vitality
Possibility of future endodontic treatment
💸 Financial costs:
Lab and material fees
Multiple appointments
May not be accessible to all patients
What are the top 3 benefits of crown placement?
1️⃣ Aesthetic enhancement (shape, colour, symmetry) ✨
2️⃣ Functional strength – withstands occlusal loads 💪
3️⃣ Protection of underlying tooth 🛡️, esp. post-RCT
How does bruxism affect crown planning?
😬 Causes excessive occlusal forces
🦷 Can lead to fracture or wear of crown
🔲 May require metal-based materials for durability
🌙 Consider prescribing nightguards for protection
What are important material factors in crown success?
🧪 Bonding system – Self-adhesive, dual-cure, etc.
🔬 Surface prep – Etching, priming, sandblasting as required
🧱 Material being bonded to – Enamel vs dentine, core material
⚠️ Avoid eugenol-based temporary cement – It inhibits resin polymerisation, reducing bond strength ❌
What operator-related factors affect outcome?
🧑⚕️ Clinician experience
✍️ Ability to perform precise crown prep
🧼 Moisture control during bonding
🔧 Proper cementation technique
🧠 Understanding of materials used
Compare crown types and their uses.
What is the best crown for a heavily restored posterior tooth?
💪 Full veneer crown (FVC) – Offers maximum strength
🪙 Gold alloy is premium but costly
🪙 Non-precious metal is more affordable
How do crowns assist partial dentures?
🦷 MCC crowns can include:
Rest seats
Guide planes
Retentive clasps
Used to support cobalt-chrome (CoCr) partial dentures
Clinical scenario: UR2 is root-treated with a composite core. What’s next?
👑 Crown placement is ideal to:
💅 Improve aesthetics
🛡️ Protect the brittle tooth
✅ Provide long-term stability
When deciding between composite or crown for a fractured tooth, what should be considered?
UL1 with mesio-incisal fracture:
Composite if small fracture, aesthetics preserved
Crown if there’s extensive damage, for better strength & protection
💡 Always balance conservation vs durability
