title: Long-term clinical evaluation of the color stability and stainability of acrylic resin denture teeth.
abstract: BACKGROUND
  The color stability and staining of acrylic resin denture teeth remains an esthetic problem for complete denture wearers.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the long-term clinical color stability and stainability of acrylic resin denture teeth in complete denture wearers over a period of 5 years.
  
  
  METHODS
  Fifty participants rehabilitated with complete dentures from February 2008 to December 2013 were selected. The demographic data and the clinical characteristics of participants were recorded. Color change (ΔE) in 3 regions of the denture teeth (incisal, middle, and cervical) was evaluated by spectrophotometry in the CIE L*a*b* system. Participants were asked whether they had noticed any changes in the coloring of the teeth in their dentures. Hierarchical clustering analysis was used to identify groups formed from variables related to demographic questions and color analysis. Two-way ANOVA among the color cluster groups was performed and the Tukey-Kramer test was used as a post hoc test (α=.05). A chi-square test and Fisher exact test were used to identify the association between the study variables and color changes in the participants' responses (α=.05).
  
  
  RESULTS
  Four cluster groups from 50 participants were identified in the clustering analysis. The ΔE was statistically significant for the interaction between the dental third and cluster groups (P<.001). Cluster groups 1 and 4 exhibited statistically higher ΔE values than cluster groups 2 and 3 (P<.05). Greater chromatic alterations were noted in the incisal third of the teeth than in the cervical and medium thirds in the cluster groups 1 (ΔE=11.03 ±1.22) and 3 (ΔE=4.14 ±1.14) (P<.05). No relationship was found with the participants' personal opinions about color change (P>.05).
  
  
  CONCLUSIONS
  Although the acrylic resin denture teeth exhibited color instability and staining in vivo, the participants were unable to identify the color change. The cluster groups with higher color change values consumed more staining solutions.
authors: Assistant Professor, Department of Prosthodontics and Periodontology, University of Campinas (UNICAMP), Piracicaba Dental School, Piracicaba, Sao Paulo, Brazil. Electronic address: vbarao@unicamp.br.
authors: Valentim Adelino Ricardo
authors: VA
authors: Barão
authors: Graduate Student, Department of Prosthodontics and Periodontology, University of Campinas (UNICAMP), Piracicaba Dental School, Piracicaba, Sao Paulo, Brazil.
authors: Erika Shiguematsu
authors: ES
authors: Ogawa
authors: Assistant Professor, Department of Oral Surgery, Pathology and Dental Clinical, University Federal de Minas Gerais (UFMG), School of Dentistry, Belo Horizonte, Minas Gerais, Brazil.
authors: Amália
authors: A
authors: Moreno
authors: Full Professor, Department of Prosthodontics and Periodontology, University of Campinas (UNICAMP), Piracicaba Dental School, Piracicaba, Sao Paulo, Brazil.
authors: Marcelo Ferraz
authors: MF
authors: Mesquita
authors: Section Chief, Maxillofacial Prosthodontics, Nebraska-Western Iowa Health Care System; Special Associate Professor, Department of Prosthodontics, Creighton University, Omaha, Neb.
authors: Alvin G
authors: AG
authors: Wee
authors: Associate Professor, Department of Dental Materials and Prosthodontics, University Estadual Paulista (UNESP), Araçatuba Dental School, Araçatuba, Sao Paulo, Brazil.
authors: Wirley Gonçalves
authors: WG
authors: Assunção
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003116:Color; D003118:Color Perception; D003430:Cross-Sectional Studies; D003764:Dental Materials / Q000737:chemistry*; D003824:Denture, Complete; D004955:Esthetics, Dental; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008689:Methacrylates / Q000737:chemistry; D008875:Middle Aged; D019904:Polymethyl Methacrylate / Q000737:chemistry; D013053:Spectrophotometry / Q000379:methods; D013499:Surface Properties; D014093:Tooth, Artificial
chemical_list: D000180:Acrylic Resins; C000601793:Biotone; D003764:Dental Materials; D008689:Methacrylates; C004919:ethylene dimethacrylate; D019904:Polymethyl Methacrylate