How to Fill a Cavity on a Dental Typodont Model
Learn the dental restoration process by preparing, etching, bonding, and composite-filling an artificial cavity on a practice typodont model.
- Read the tools, materials, safety notes, and steps below for free.
- Tap Start Camera Coach when you want hands-free voice help.
- Allow camera and microphone. Point your phone at the work; the coach watches your progress and tells you the next step.
🧰 Required Tools & Equipment
- ✓ Dental micromotor or rotary tool with micro round bur
- ✓ Dental explorer probe
- ✓ Micro-applicator brushes
- ✓ Dental LED curing light (450nm)
- ✓ Composite filling instrument / plastic instrument
- ✓ Articulating paper with forceps
📦 Materials & Supplies
- ✓ Typodont dental training model with simulated carious tooth
- ✓ 37% Phosphoric acid etch gel
- ✓ Dental bonding agent (adhesive)
- ✓ Light-cure composite resin (A2 shade)
- ✓ Fine-grit composite finishing and polishing discs
⚠️ Safety Checkpoints & Warnings
- • Wear UV-filtering amber safety glasses when operating the dental curing light to prevent retinal damage.
- • Wear safety goggles and a dust mask when operating rotary burrs on acrylic teeth to avoid airborne particle inhalation.
- • Practice strictly on inanimate typodont models; never attempt invasive procedures on living human or animal tissue.
📋 Step-by-Step Guide (6 Steps)
Excavate Simulated Decay and Shape the Cavity
Mount the typodont securely and use a small round bur on low speed to gently remove all discolored soft material from the target tooth pit or fissure. Create clean, distinct vertical cavity walls and a smooth floor with slight undercut retention. Clear plastic dust debris with compressed air or a soft dry brush.
- • Cavity preparation has crisp, well-defined margins with no dark simulated decay remaining.
- • Cavity floor is flat and uniform without deep gouges into the tooth pulp chamber.
- • Running the bur at excessive RPM, causing the plastic tooth to melt and gum up the bur.
- • Over-excavating and destroying adjacent sound tooth structure or puncture through the base.
Apply Phosphoric Acid Etchant Gel
Dispense a small bead of 37% phosphoric acid blue gel directly into the prepared cavity walls and floor. Allow the etchant to condition the interior surface for 15 seconds. Rinse thoroughly with water using a syringe and gently blot dry, leaving the surface clean and chalky-matte.
- • Blue etchant gel covers all internal prep margins completely.
- • Dried cavity interior appears uniformly dull and matte without leftover blue residue.
- • Leaving etchant on for too long or failing to wash it out completely before drying.
- • Over-drying until the surrounding model plastic cracks or dehydrates excessively.
Apply and Air-Thin Bonding Adhesive
Dip a fresh micro-applicator into the bonding adhesive and scrub it thoroughly into all internal walls of the cavity for 10 seconds. Gently direct a low-pressure puff of air across the prep to evaporate the solvent carrier until the adhesive layer stops rippling. Light-cure the adhesive layer with the curing light for 10 seconds.
- • Cavity interior exhibits a uniform, glossy sheen with no pooling in internal corners.
- • Bonding layer is fully cured and firm to an explorer tip touch.
- • Applying too thick of a coat, causing pooling that alters the cavity depth.
- • Forgetting to air-thin the adhesive before light activation.
Place and Sculpt Composite Resin Increments
Place composite resin paste into the cavity in increments no thicker than 2 mm to avoid polymerisation shrinkage. Use the flat composite instrument to pack and adapt the resin against the preparation walls. Sculpt the natural occlusal anatomy, matching the grooves and ridges of the adjacent tooth anatomy before curing.
- • Composite is seamlessly blended into tooth margins without flash or voids.
- • Anatomical fissure lines and cusp slopes match adjacent natural tooth contours.
- • Placing the entire filling in one large bulk increment, resulting in uncured resin at the bottom.
- • Letting composite drag or pull away from margins when lifting the instrument.
Light-Cure the Composite Restoration
Position the curing light tip directly over the restoration at a 90-degree angle, approximately 1-2 mm from the surface. Activate the LED curing light for a full 20-second cycle per increment placed. Perform an additional cure from the buccal and lingual angles to ensure complete depth of polymerization.
- • Composite surface is rock-hard and produces a solid clicking sound when tapped with a metal probe.
- • Material has changed from translucent/waxy to a fully solidified, uniform shade.
- • Holding the light wand too far away or angled obliquely, reducing effective curing energy.
- • Cutting the curing cycle short before the resin reaches full hardness.
Check Occlusion, Trim Margins, and Polish
Place articulating paper over the tooth and close the typodont jaws to check for high contact spots (dark marks). Use a fine finishing disc on low RPM to smooth down heavy marks and blend margins flush with the tooth surface. Buff the entire restoration with a polishing cup until it matches the natural gloss of the typodont tooth.
- • Articulating paper leaves light, balanced contact dots matching surrounding teeth.
- • Margin between tooth acrylic and composite is completely smooth and imperceptible to an explorer tip.
- • Over-polishing and flattening out the anatomy that was sculpted in Step 4.
- • Leaving a sharp 'catch' ledge where composite overlaps uncut tooth enamel.
Credit: inspired by an original tutorial by Dental Digest — watch the original on YouTube.
Don’t have everything?
- No Dental micromotor handpiece? Variable-speed rotary tool (Dremel) set to lowest RPM with a 1mm carbide ball bur
- No Composite plastic instrument? Wax carving spatula or flat-edged metal modeling tool