A COMPARISON OF DIMENSIONAL ACCURACY IN THE DENTURES PROCESSED BY COMPRESSION MOLDING AND INJECTION MOLDING TECHNIQUES- AN IN VITRO STUDY

*Sabnoor Aujla, M.D.S, Sanjeev Mittal and Mamit Kumar, MDS

ABSTRACT

Purpose: To compare the linear dimensional changes in the dentures fabricated by Injection Molding and Compression Molding Technique. Materials and method: Thirty identical maxillary and mandibular denture bases were duplicated in dental wax with anatomic teeth from a master waxed-up denture by preparing a silicon mold using pourable addition silicon. Samples were divided into three groups (A, B and C) with 10 each. Waxedup dentures. Group A samples were fabricated by Injection molding technique using SR-Ivocap. Group B samples were fabricated by Compression Molding technique using Triplex Hot, Ivocap and Group C samples were fabricated by Compression Molding technique using Acrylin-H. Measurements in triplicate were made Anteroposteriorly( A-B) and Mesio-Laterally (A-C and B-D) between the reference points scribed on Second Premolar and Second Molar of maxillary and mandibular teeth with a traveling microscope (accurate to 0.005 mm). All the measurements were made by the same investigator at three different stages i.e. processed denture after 12 hours, Denture after finishing and polishing and after Storage in water at room temperature for 30 days. Data were analyzed by using appropriate tests. Results: Group-A maxillary denture showed expansion in all dimensions whereas mandibular denture showed expansion in antero-posterior and contraction in cross arch after curing. Compression Molded group-B and group-C showed contraction after curing of maxillary and mandibular denture. The maximum mean percentage change was found in group C followed by group B and minimum mean and mean percentage change was found in group A. This difference between the two techniques was statistically significant (P<0.05). Conclusion: Within the limitations of this study, Injection Molding System resulted in a less dimensional change than conventional polymerization techniques, the difference being significant for Injection molding technique using SR-Ivocap. (p<.05) compared with the conventional technique. Maximum dimensional change was exhibited by Compression Molding Acralyn-‘H’.

Keywords: Denture, Dimensional change, Maxilla, Mandible.