Occlusal factors in failure

Question 1

What are some clinical signs that suggest occlusal failure? 🤕

Answer 1

🦷 Fractured teeth or restorations
😬 Increased tooth mobility
😣 Pain on biting
👑 Loosening of crowns

Question 2

What causes occlusal failure? 😓

Answer 2

⚠️ Excessive forces or forces in the wrong direction (especially lateral forces)
😮‍💨 Premature contacts
➡️ Lateral forces on posterior teeth
💪 Strong forces acting on weak or compromised teeth

Question 3

How can we prevent occlusal-related failures? 🛡️

Answer 3

🔍 Perform thorough occlusal screening exams on every patient
Check:
👄 ICP (Intercuspal Position)
↔️ Lateral guidance
😬 Repeated restoration failures
👄 Protrusion forces on restored anteriors
😮‍💨 Wear facets on at-risk teeth
🔁 RCP–ICP slide in anterior wear
⚡ Non-working side interferences (especially if palatal fractures are seen!)

Question 4

What is the role of canine guidance? 🐕

Answer 4

💥 Protects posterior teeth by taking lateral load
🧱 BUT! Canine must be structurally strong to do this
✔️ Preferable when possible

Question 5

What is group function? 👥

Answer 5

🧓 Seen more commonly with age
☑️ Acceptable when load is shared across multiple posterior teeth
☁️ Cusps should be flatter to reduce damaging forces

Question 6

What should you avoid when planning lateral guidance? ❌

Answer 6

🚫 Should NEVER be on a post-crowned tooth
❌ Avoid placing guidance on a bridge pontic

Question 7

What is a diagnostic wax-up and when is it used? 🧼🦷

Answer 7

✍️ A mock-up of the teeth using wax
✅ Mounted in RCP (Retruded Contact Position)
🧠 Done on an articulator
🔍 Helps visualize occlusal possibilities and changes

Question 8

What is an occlusal interference? 🚧

Answer 8

😬 A heavy tooth contact that disrupts the normal path of jaw movement
Can occur during:
👄 ICP
🔁 RCP
⏩ Protrusion
🔄 Working-side
🔁 Non-working side

Question 9

What are the effects of ICP interferences? 🤕

Answer 9

😓 May feel “high” to the patient
🦷 Causes:
Pain
Increased mobility
Tooth sensitivity
Restoration failure
❗ ALWAYS correct occlusion before the patient leaves!

Question 10

What are working side interferences? 🤨

Answer 10

😣 Occur when canine guidance is missing
⛔ Lateral forces affect:
🦷 Buccal cusps of upper teeth
🦷 Lingual cusps of lower teeth
💡 BULL Rule = Buccal Upper, Lingual Lower

Question 11

What are non-working side interferences and how do they present? ❌

Answer 11

Happen when teeth on the opposite side contact during lateral movement
🦷 Affects:
Palatal cusps of upper teeth
Buccal cusps of lower teeth
💡 PUBL Rule = Palatal Upper, Buccal Lower
🌀 Wear pattern: Semi-circular on upper teeth
😮 Can lead to mobility and fractures, especially palatal

Question 12

What occlusal factors should be considered when planning restorations? 🛠️

Answer 12

🧾 Include occlusal “check-up” in every exam
🔒 Is ICP stable?
🦷 Are teeth in guidance structurally compromised?
🧠 Match occlusion before and after treatment
🧰 Choose articulator based on lateral force risks:
🧍‍♂️ Conforming: Use ICP record
🔁 Re-organizing: Use RCP

Question 13

Case 1: LL6 has lingual cusp fracture + cracked tooth syndrome. Interference? 🤕

Answer 13

➡️ Working side interference
💡 Solution: Remove interference + proper restoration

Question 14

Case 2: 54 y/o female, pain on biting UL7 (palatal cusp mobile). Interference? 😖

Answer 14

➡️ Non-working side interference
🛡️ Needs an occlusal splint to protect against bruxism (grinding)

Question 15

What happens during non-working side interferences? 😳

Answer 15

Teeth on the opposite side of the jaw clash unexpectedly during movement 😱

Question 16

Case 3 - 67yo getting crowns, says bite feels “high.” What’s the issue? 🏔️

Answer 16

➡️ ICP interference
👩‍🔧 Solution:

High in excursion? ✂️ Reduce cusp height
“Free” in excursion? 🔍 Deepen the fossa

Question 17

Case 4 - 36yo male keeps breaking anterior composites. Why? 😩
A23:

Answer 17

➡️ Protrusive interference
💡 Build up canines to take the force off the front teeth 💪🐶

Question 18

Can you bring back canine guidance if it’s worn down? 😃

Answer 18

Yes! But you must evaluate first:

🧪 Periodontal status
💓 Pulp vitality
📸 Periapical radiograph
📐 Root length + angulation
🚫 No RCTs or posts!

Question 19

How do you plan to rebuild canine guidance? 📊

Answer 19

🦷 Take study models
🧠 Record RCP
🧰 Mount on semi-adjustable articulator
💌 Request diagnostic wax-up from the lab
✍️ Plan build-up for canines to protect anterior teeth

Question 20

What is Shimstock used for? 🪙

Answer 20

It’s a thin (8μm) metal foil used to detect occlusal contacts – if the tooth holds the Shimstock while biting, it’s in contact 👀🧾