Evaluation of Patient Satisfaction and Microbiological Changes in Injectable Thermoplastic Resin and Conventional Acrylic Resin Complete Dentures

The restoration of masticatory function and aesthetics is an important aim in dentistry mainly when patients present with extensive tooth loss. The loss of tooth in elderly patients not only impairs the stomatognathic system but also their psychological status and quality of life.so an important criteria's for the success of dentures are patient's expectations and the ability of the denture to replace the lost masticatory efficiency.

The acrylic resin was first used in 1936; it was in that time the best alternative for vulcanized rubber. Where it is characterized by superior characteristics and became the most popular material used since then. Nonetheless, it has some problems such as polymerization shrinkage, weak flexural, lower impact strength, and low fatigue resistance. These often lead to denture failure during chewing or when fall out of the patient's hand. In order to enhance some properties of PMMA, various efforts have been taken including addition of metal wires or plates, fibers, metal inserts, and modification of chemical structure. In recent years, nylon polymer has attracted attention as a denture base material.

Thermoplastic nylon like materials or polyamides were introduced and first used in dentistry in 1950. The polyamide are uniquely characterized by high esthetics especially in removable partial dentures, where retentive components are recommended anteriorly by this material which provide high elasticity we can make the retentive components using the same material and eliminate the metallic clasps.

Polyamides are characterized by low weight and flexibility make it more patient satisfactory and fortunately it has no monomer remnants that may affect patient health and causes allergy. Thermoplastic polyamides have almost no porosity which eliminates water sorption. The technique used for its fabrication is injection molding technique which is more dimension accurate than packing mold technique.

Valplast was initially used just over 50 years ago and has been used in modern dentistry since the mid-fifties. A variation of nylon, which is far more flexible and stronger than poly methyl methacrylate resin, is used in many alternative partial dentures. Valplast flexible dentures are used for full sets of dentures especially in cases of acrylic allergy which represent 20% of the population.