Denture Relining & Rebasing Deptt: Of Prosthodontics By Dr. Aamir Mehmood Butt, Assistant Professor Deptt: Of Prosthodontics LUMHS, Jamshoro

Denture Relining Definition: “ procedure used to resurface the tissue side of a denture with new base material, producing an accurate adaptation to the denture foundation area” ( GPT 2005)

Indications 1. Resorption of the bone could leads to: Loss of retention & stability Loss of VD Loss of support of facial tissues Incorrect occlusal relationship Immediate denture after 3 -to - 6 months of construction. Economics Geriatric or chronically ill pt: Time problem Loose denture at the time of delivery

Contra- Indications Poor quality of denture base Exaggerated bone resorption Abused or traumatic oral tissues Poor teeth arrangement Unsatisfactory jaw relationship Speech problem Undercuts TMJ problems.

Relining Materials According to time: Short–term liners example: tissue conditioners, preformed sheets of acrylic gel. b long-term liners plasticized acrylic( heat & chemical activated forms are available) Heat activated silicones RTV ( room temperature vulcanization ) silicones Plasticized vinyl polymers & copolymers Hydrophilic polymers Polyphosphazine fluoropolymers Fluoroethylene PVS

Relining Materials According to type of Activation Heat activation Chemical activation

Uses of short-term liners Treatment & conditioning of abused oral & supporting tissues. Diagnostic purposes such as recovery of VD. Temporary relining of immediate denture/ surgical splints/ cleft palate speech aids etc. Tissue conditioning during implant healing. Functional impression material.

Qualities of an ideal long-term reliner Biocompatibility Dimensional stability Low water sorption & solubility Low surface tension Permanent softness Abrasion resistance Good bond to denture base material Simple to manipulate Color stability Resist microorganisms growth

Comparison of plasticized acrylic versus silicon rubber Less resilient Hardens by time Good bonding with base material Acceptable tear resistance Better abrasion resistance Resistance to damage by denture cleansers

Comparison of plasticized acrylic versus silicon rubber SILICONE RUBBER: Highly resilient Poor bonding to acrylic denture base More water sorption More susceptibility to microorganism growth Low tear & abrasive resistance Less resistance to damage by denture cleansers

REBASING DEFINITION: “ The laboratory procedure of replacing the entire denture base material on an existing prosthesis” (GPT 2005)

Indications Where the observed clinical changes are moderate to sever. Some processing fault in denture base e.g: porosity Discoloration of base material. Where porcelain teeth have been used.