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Dimensional change in complete dentures fabricated by injection molding and microwave processing
Phillip L J Keenan1, David R Radford, Robert K F Clark
1Guy's, King's and St. Thomas' Dental Institute, King's College, London, United Kingdom.
The Journal of Prosthetic Dentistry
|February 18, 2003
Summary
Injection molding and microwave polymerization techniques for complete dentures showed minimal dimensional changes compared to conventional methods. These findings suggest improved clinical fit and reduced long-term adaptation issues for patients.
Area of Science:
- Dental Materials Science
- Prosthodontics
- Polymer Chemistry
Background:
- Acrylic resin complete dentures exhibit dimensional changes during polymerization, impacting clinical fit.
- Injection molding and microwave polymerization are advanced techniques aiming to minimize these changes.
- Quantifying dimensional alterations is crucial for improving denture fabrication and patient outcomes.
Purpose of the Study:
- To compare dimensional changes in simulated maxillary complete dentures fabricated using injection molding and microwave polymerization versus conventional methods.
- To evaluate the impact of different polymerization techniques on intermolar width and vertical dimension of occlusion.
- To assess dimensional stability after storage in water for 28 days.
Main Methods:
- Forty simulated maxillary denture bases were fabricated and divided into four groups: conventional compression molding, injection molding with conventional polymerization, and two types of injection molding with microwave polymerization.
- Intermolar width and vertical dimension of occlusion were measured after polymerization and after 28 days of water storage.
- Measurements were performed using a traveling microscope and an internal micrometer, with data analyzed via one-way ANOVA.
Main Results:
- All polymerization methods resulted in shrinkage, with injection molding techniques showing slightly less post-polymerization increase in vertical dimension of occlusion compared to conventional methods.
- While Microbase specimens exhibited greater shrinkage, no significant differences in intermolar width were found between groups.
- Only the Microbase group showed a statistically significant difference in vertical dimension of occlusion compared to the conventional control.
Conclusions:
- Injection molding techniques, particularly with microwave polymerization (Microbase), demonstrated a trend towards reduced vertical dimension of occlusion increase compared to conventional polymerization.
- The study suggests that advanced polymerization methods may offer marginal benefits in controlling dimensional changes in complete dentures.
- Further research is warranted to fully elucidate the long-term clinical implications of these findings.