Denture Repairs, Relining and Rebasing Explained Simply

Dentures are dropped in sinks, flexed thousands of times daily while chewing, and the jawbone beneath them slowly shrinks year after year. A repair fixes a broken part such as a cracked base; a reline adds a new fitting surface inside so the denture grips again; a rebase replaces the entire pink base while keeping the existing teeth.

A loose or broken denture causes sore spots, slips during speech and reduces chewing to soft foods. Knowing which of the three is needed saves patients from paying for a brand-new denture when a simpler fix would do.

Key Concepts

• Midline fracture: the classic break — a crack down the middle of an upper denture from repeated chewing flexure.
• Autopolymerising (cold-cure) acrylic: repair resin hardening chemically at room temperature; lab-processed heat-cured acrylic is stronger.
• Direct vs indirect reline: chairside reline in one appointment vs an impression sent to the lab for a heat-cured result.
• Tissue conditioner: a soft temporary liner cushioning sore gums for a few days before the final reline impression.
• Residual ridge resorption: gradual jawbone shrinkage under a denture — why a once-perfect fit loosens over years.

How It Works

A fracture repair runs as follows: pieces are fitted exactly and held with sticky wax on the outer side, a plaster index supports the denture, the fracture is ground into a dovetail groove on the tissue side, fresh autopolymerising acrylic is packed in and cured, then trimmed, polished and tried in the mouth.

For a reline, the dentist confirms the teeth still meet correctly, roughens the old tissue surface, and records a wash impression of the current gum shape inside the denture with the patient closing into their normal bite; the lab processes a new heat-cured fitting surface. A rebase keeps the teeth in position while replacing the whole worn or stained base.

Worked Example

Mixing repair acrylic at the correct ratio — typically about 3 parts polymer powder to 1 part monomer liquid by volume (brands vary; always check the leaflet). For a repair needing 15 mL of mixed resin, the 4 total parts are 15 ÷ 4 = 3.75 mL each: powder = 3 × 3.75 = 11.25 mL, liquid = 1 × 3.75 = 3.75 mL. Too much liquid gives a weak, porous repair that breaks again; too little leaves dry, unbonded powder.

Common Misconceptions

• Superglue is fine for a broken denture. It is toxic to mouth tissues and contaminates the fracture so a proper acrylic repair will not bond afterwards.
• Reline and rebase are the same. A reline resurfaces only the tissue side; a rebase replaces the entire base.
• A loose denture always needs replacement. If teeth, bite and appearance are still good, a reline often restores a snug fit for a fraction of the cost.

Real-World Applications

• Emergency fracture repairs — among the most common same-day prosthodontic procedures.
• Routine relines every few years as ridges resorb under long-term dentures.
• Implant overdenture maintenance, relining around worn housings and inserts.

Repair, reline and rebase keep removable prostheses working for decades: fix what broke, refit what loosened, replace only what is worn out — and most dentures never need remaking from scratch.