Scientific Online Resource System

Scripta Scientifica Medicinae Dentalis

An injection molding device, improving the existing injection system for acrylic denture fabrication

Kalina Georgieva, Metodi Abadjiev


Introduction: The advantages of injection molding system (IMS) are precise adaptation of acrylic to master cast, continuous compensation of acrylic shrinkage, low porosity and better physical properties of dentures. Traumatic, toxic and allergic complications are reduced.

The existing IMS produces only one denture at a time. Using standard capsules leads to waste of material. Removable partial acrylic dentures (RPAD) with wire clasps haven`t been fabricated yet.

Materials and methods: The objective is to construct a device for serial injection fabrication of acrylic dentures optimizing both working time and cost of restoration.

The device should:

  • provide a precise adaptation of material to master cast
  • reduce residual monomer
  • fabricate a lot of dentures for a short time
  • fabricate RPAD with wire clasps
  • optimize the amount of material

A prototype of the device is designed and constructed.

Results: The new device is based on the existing IMS.

The following improvements are applied:

  • The serial fabrication is achieved by dividing the injection and polymerization process by including a specially designed cap which is fixed on the flask after acrylic injection. It provides continuous pressure during the polymerization process. This allows fabrication of large number of dentures at the same time, injected by a single pneumatic cylinder.
  • RPAD with wire clasps are fabricated by fixing the clasps with cold-cured acrylics and mechanical retention in the master mast.
  •  Capsules for multiple fabrication are  used.                                                                                               

Conclusion: A serial injection of large number of dentures as well as separate processing of each of them is possible at a time. The waste of material is reduced. Fabrication of RPAD with wire clasps is achieved.  


acrylic dentures; injection molding device

Full Text


Wu B, Liang J, Plassman BL, Remle C, Luo X. Edentulism trends among middle-aged and older adults in the United States: comparison of five racial/ethnic groups. Community Dent Oral Epidemiol. 2012 Jun;40(3):288.

Mojon P, Thomason JM, Walls AW. The impact of falling rates of edentulism. The International Journal of Prosthodontics. 2004;17(4):434-440.

Petersen PE, Kandelman D, Arpin S, Ogawa H. Global oral health of older people - Call for public health action. Community Dental Health. 2010; 27(Suppl 2):257-268.

Mutti NM, Pazzini LI. Horizontal fit of flasks as a factor in complete denture disarticulation. The Journal of Prosthetic Dentistry. 1974;32(4):448-452.

Matsuda R, Yoneyama Y, Morokuma M, Ohkubo Ch. The influence of vertical dimension of occlusion changes on the electroencephalograms of complete denture wearers. Journal of Prostodontic Research. 2014;58:121-126.

Dogan A, Bek B, Çevik NN, Usanmaz A. The effect of preparation conditions of acrylic denture base materials on the level of residual monomer, mechanical properties and water absorption. Journal of Dentistry. 1995;23(5):313-318.

Pryor WJ. Injection molding of plastics for dentures. J Am Dent Assoc. 1942;29:1400-1408.

Anderson GC, Schulte JK, Arnold TG. Dimentional stability of injection and conventional processing of denture base acrylic resin. Dental Technology. 2nd ed. 1988;60(3):394.

Nogueira SS, Ogle RE, Davis EL. Comparison of accuracy between compression- and injection-molded complete dentures. The Journal of Prosthetic Dentistry. 1999;82(3):291-300.

Shadi EB, Ludwig K, Shamran A et al, Linear and volumetric dimensional changes of injection-molded PMMA denture base resins. Dental materials. 2013;29:1091-1097.

Garfunkel E. Evaluation of dimensional changes in complete dentures processed by injection-pressing and the pack-and-press technique. J Prosthet Dent. 1983;50(6):757-761.



About The Authors

Kalina Georgieva
Medical unversity of Varna

Department of prosthetic dental medicine and orthodontics, Faculty of dental medicine

Metodi Abadjiev
Medical unversity of Varna

Department of prosthetic dental medicine and orthodontics, Faculty of dental medicine

Font Size