Shelf-life of tooth-coloured restorative materials in Papua New Guinea

A survey of Dental Officers and Dental Therapists in Government Health and Defence Force Clinics throughout Papua New Guinea indicated that the problem of slow setting and even failure to set is a frequent occurrence with composite resin materials. This is because these materials tend to deteriorate at high temperatures to which they may be subjected during transport, initial storage and clinical storage awaiting use. Eight brands of composite resin, including paste-paste, powder-liquid and light-activated systems, as well as three glass ionomer cements were evaluated over a period of twelve months with respect to shelf-life and suitability for use in a tropical environment. Preliminary results indicated that, although a light-activated composite resin appeared to be the material of choice, it may not be suitable because it is relatively expensive and requires a curing light which is electrically operated. A powder-liquid composite resin was, therefore, the recommended product. On the other hand, it was also suggested that a powder-water glass ionomer cement, Chemfil II, might be a suitable alternative for a developing, tropical country such as Papua New Guinea.