title: Effect of home reliner on occlusal relationships and oral mucosa: viscoelastic analyses by smoothed particle hydrodynamics simulation.
abstract: BACKGROUND
  For decades, many reports have expressed negative opinions about home reliner (HR), because it may result in residual ridge resorption. Recently, some clinical studies evaluated HR. However, the effect of HR on occlusal relationships and the oral mucosa remains unclear. Here, we dynamically analyzed the situation in which a patient applies HR to an upper complete denture.
  
  
  METHODS
  We numerically simulated the effect of HR on occlusal relationships and the oral mucosa. In the simulation, the thickness of HR was set to 2mm as a proper amount and 4mm as an excessive amount. The loading points were set at the center of the right and left occlusal surfaces of the denture.
  
  
  RESULTS
  Compared with the case without using HR, at proper amounts (2mm on the right and left sides), HR suppressed the depression of the ill-fitting denture, and stress on the oral mucosa was decreased. In the excessive HR model (4mm on the right and left sides), the vertical occlusal dimension was increased, and stress on the oral mucosa originally fitted with the denture base was increased. When the denture was modeled in an inclined position (2mm on the left side and 4mm on the right side), stress on the oral mucosa on the left buccal side was markedly increased.
  
  
  CONCLUSIONS
  It was found that when an improper amount of HR was applied, the occlusal vertical dimension increased and the oral mucosa was pressured more than that under non-HR conditions.
authors.affiliation: Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. Electronic address: d.hirayama.ore@tmd.ac.jp.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Hirayama
authors.affiliation: Graduate School of Environment and Information Science, Yokohama National University (YNU), 79-1 Tokiwadai, Hodogaya, Yokohama 240-8501, Japan. Electronic address: ysakai@sphlab.co.jp.
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Sakai
authors.affiliation: Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. Electronic address: n.akiba.ore@tmd.ac.jp.
authors.forename: Norihisa
authors.initials: N
authors.lastname: Akiba
authors.affiliation: Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. Electronic address: m.kanazawa.gerd@tmd.ac.jp.
authors.forename: Manabu
authors.initials: M
authors.lastname: Kanazawa
authors.affiliation: Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. Electronic address: s.minakuchi.gerd@tmd.ac.jp.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Minakuchi
mesh_terms: D001696:Biomechanical Phenomena; D003198:Computer Simulation; D003799:Dental Stress Analysis / Q000379:methods; D003827:Denture, Complete, Upper; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D057446:Hydrodynamics; D015233:Models, Statistical; D009061:Mouth Mucosa; D014783:Viscosity
keywords: Complete denture; Finite element method; Home reliner; Nonlinear; Oral mucosa; SPH method; Viscoelastic