Partial dentures 3 new Flashcards
. What are the 5 key components of partial denture design? 🔧
🪑 Saddle – Replaces missing teeth
🧱 Support – Resists vertical (biting) forces
🧲 Retention – Stops denture from being pulled away
↔️ Reciprocation – Balances out clasp forces
🔗 Connectors – Joins everything together rigidly
What does the saddle of a partial denture do? 🪑
Replaces the missing teeth
Includes denture teeth, base, and flange
Extends away from gingival margins
Design must cors out any teeth not being replaced
Mark saddle areas clearly on design sheet
What’s the difference between mucosa-borne and tooth-borne support? 💡
Mucosa-borne:
Relies on soft tissues
Needs wide surface area
Less stable
Tooth-borne:
Relies on natural teeth
Needs rests for support
More stable & preferred in Class III dentures ✅
What are rests, and where are they placed? 🔩
Rests = 🧱 little “shelves” to support denture from vertical forces
Transmit forces down long axis of abutment tooth
How do you prepare an occlusal rest? 📐
Within enamel only
1 mm deep
⅓ the width of the tooth
Must be broad, smooth, and rounded
How is a cingulum rest prepared? 🦷
Used on canines/incisors
If no flat surface → add composite to form one
Often used for indirect retention too!
What’s the “4 corners of support” rule? 🪜
Like a table with 4 legs!
Rests should be spread across 4 areas for even support
If a tooth isn’t available:
Use tuberosity (maxilla)
Use retromolar pad (mandible)
What provides retention for partial dentures? 🧲
Clasping into undercuts
Saliva (adhesion + cohesion)
Friction of denture against teeth
Accessory methods: magnets, studs, etc.
What is a survey line? 🕵️♀️
Line drawn at bulkiest contour of the tooth
Above = non-undercut
Below = undercut
Helps plan clasp placement
How do clasps work to provide retention? 🪝
Engage undercuts below survey line
Need to flex into place but resist removal
Come in different materials for different undercut depths!
What’s a 3-arm clasp, and how does it work? 🤖
🪝 Used in occlusally approaching designs
3 parts:
Retentive arm – flexible, goes into undercut
Reciprocal arm – rigid, on opposite side
Rest – provides support
💡 Retentive arm:
⅔ above survey line
Final ⅓ in undercut
What’s the purpose of reciprocation? ↔️
Balances out the inward force of the clasp
Prevents tooth tipping or mobility
Provided by:
Reciprocal arm
Rigid connectors
Lingual plates
What’s the difference between occlusally and gingivally approaching clasps? 🔽🔼
Occlusally approaching:
Comes from above
3-arm clasp
More visible 👀
Gingivally approaching:
Comes from below (e.g., I-bar)
More aesthetic 💅
Less retentive 😬
What clasp types are used for acrylic dentures? 🧷
C-clasps
I-bars
Adams clasps
Ball-ended clasps
How many clasps should a denture ideally have? 🧮
✅ One clasp per end of the saddle
❌ No more than 4 clasps total
More than that = difficult insertion & trauma risk
Which clasp types are used for which teeth? 👑
What are guide planes, and why are they important? 🚪
Flat, smooth surfaces on tooth
Guide the path of insertion/removal
More parallel = more stability & retention!
What are major connectors, and what do they do? 🔗
Connect all parts of the denture
Provide rigidity, support, and bracing
Distribute forces evenly
What are the types of lower major connectors? ⬇️
What are the types of upper major connectors? ⬆️
What does bracing do in a denture? 🛡
Prevents horizontal movement
Often provided by:
C-clasps
Lingual plates
Major connectors
Final Lab Checklist Before Sending Design? 🧾
✅ Rests prepared
✅ Surveying done + undercuts marked
✅ Clasp types chosen and positioned
✅ Guide planes marked
✅ Major connector type decided
✅ Saddles corsed out and drawn
✅ Arrows drawn for insertion path
Which teeth do we clasp
Lingual plate
Dental bar
label
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