title: Dye penetration in dry and water-filled gaps along root fillings.
abstract: OBJECTIVE
  The aim of this study was to investigate the influence of hydration in voids along root fillings on methylene blue penetration.
  
  
  METHODS
  A total of 80 human root canals were prepared using a step-back technique and filled with a zinc oxide based sealer and gutta-percha. Leakage along the fillings was measured by a transport fluid model and classified into three categories: gross leakage (GL), slight leakage (SL) and no leakage (NL). Specimens with NL and SL were immersed into methylene blue (MB) 2% for 24 h (group I). Specimens with GL which had wide gaps filled with water were randomly divided into two groups (II, III). Transport air was applied to remove water from gaps only in specimens of group III. All tested specimens from groups II and III were also immersed into MB 2% for 24 h. Each specimen was then split longitudinally and linear measurements of dye penetration were recorded.
  
  
  RESULTS
  Group III (with dry gaps) showed significantly more dye penetration than group II. No significant difference was found between group I and group II.
  
  
  CONCLUSIONS
  Methylene blue penetrates along root fillings more easily in dry gaps than in water-filled gaps.
authors: Department of Endodontics, School of Dental Medicine, Athens, Greece.
authors: E G
authors: EG
authors: Kontakiotis
authors: M K
authors: MK
authors: Georgopoulou
authors: A S
authors: AS
authors: Morfis
mesh_terms: D000388:Air; D004396:Coloring Agents; D003763:Dental Leakage / Q000145:classification; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D006171:Gutta-Percha / Q000737:chemistry; D006801:Humans; D007101:Immersion; D008751:Methylene Blue; D012212:Rheology; D012387:Root Canal Filling Materials / Q000737:chemistry*; D018915:Root Canal Preparation / Q000379:methods; D013223:Statistics as Topic; D013499:Surface Properties; D013500:Surface Tension; D014867:Water; D015034:Zinc Oxide / Q000737:chemistry; D015035:Zinc Oxide-Eugenol Cement
chemical_list: D004396:Coloring Agents; D012387:Root Canal Filling Materials; D015035:Zinc Oxide-Eugenol Cement; D014867:Water; C048769:tubliseal; D006171:Gutta-Percha; D015034:Zinc Oxide; D008751:Methylene Blue