title: A clinical 5-year longitudinal study on the dimensional changes of complete maxillary dentures.
abstract: OBJECTIVE
  Acrylic resin complete dentures exhibit dimensional changes mainly because of processing shrinkage and expansion because of water uptake. The aim of this 5-year clinical study was to determine the dimensional changes occurring during construction and in service in maxillary complete dentures made of two types of acrylic resin.
  
  
  METHODS
  Complete dentures were constructed for 17 edentulous patients. Nine patients received dentures made of conventional heat-cured acrylic resin, and eight patients received dentures made of rapid heat-cured acrylic resin. Measurements were taken across three reference points (second molars bilaterally and central incisors) on six occasions: at the flasking stage, at the denture insertion appointment, and after 1 week, 1 month, 3 months, and 5 years of use. The data obtained were analyzed using one-factor repeated-measures ANOVA, one-way ANOVA, and Duncan's multiple comparisons test.
  
  
  RESULTS
  The two types of dentures showed the same pattern of dimensional changes. A shrinkage of up to 0.27% was estimated at the insertion stage. During the first 3 months of use, a decrease of the initial dimensional change was observed. After a 3-month period, a gradual compensation for the initial shrinkage started to take place. At the end of the study period (5 years), an expansion of up to 0.35% was measured.
  
  
  CONCLUSIONS
  Maxillary complete dentures made of either conventional or rapid heat-cured acrylic resin exhibited dimensional changes that were considered clinically acceptable.
authors.affiliation: Department of Removable Prosthodontics, Dental School, University of Athens, Greece.
authors.forename: Nick
authors.initials: N
authors.lastname: Polychronakis
authors.forename: Stavros
authors.initials: S
authors.lastname: Yannikakis
authors.forename: Alcibiades
authors.initials: A
authors.lastname: Zissis
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003819:Denture Bases; D003779:Denture Design; D003827:Denture, Complete, Upper; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D014867:Water