title: Evaluation of a novel repetitive gas-enhanced permeation test for restoration leakage determination after thermo-mechanical loading.
abstract: OBJECTIVE
  To assess leakage of class-I restorations using a gas-enhanced permeation test (GEPT) as compared with conventional SEM or dye analysis.
  
  
  METHODS
  Pressure differences over time and penetrating water volumes were measured simultaneously in a two-chamber system (GEPT) before and after class I cavity preparation in 30 molars. Ten teeth were restored with a composite restoration without bonding (A1), a composite restoration with bonding (A2) or a ceramic indirect restoration (B). Five intact teeth served as controls (C). Another GEPT measurement was performed and impressions were taken. Teeth were subjected to thermodynamic loading (1 200 000 cycles) and final GEPT measurements and impressions were made. SEM evaluation of the marginal continuity was performed and teeth were subjected to a Fuchsin dye penetration test. Spearman's rank test was used to compare results from different tests.
  
  
  RESULTS
  The GEPT and SEM values did not correlate before loading (0.359, p = 0.051), but significantly correlated afterwards (0.662, p < 0.0001). The correlations between the Fuchsin dye penetration test and GEPT and SEM surface marginal analysis were significant (0.777 and 0.534, p-values < 0.0001 and 0.002, respectively).
  
  
  CONCLUSIONS
  SEM marginal analysis was mainly limited in reflecting the surface restoration integrity. GEPT evaluation may, therefore, serve as a tool to non-destructively assess restoration sub-surface integrity over time.
  
  
  CONCLUSIONS
  The current study provided proof that restoration margin quality does not necessarily reflect its leakage behaviour.
authors.affiliation: a Clinic of Preventive Dentistry, Periodontology and Cariology , Center of Dental Medicine, University of Zurich , Zürich , Switzerland .
authors.forename: Anas
authors.initials: A
authors.lastname: Al-Jadaa
authors.affiliation: a Clinic of Preventive Dentistry, Periodontology and Cariology , Center of Dental Medicine, University of Zurich , Zürich , Switzerland .
authors.forename: Danielle
authors.initials: D
authors.lastname: de Abreu
authors.affiliation: a Clinic of Preventive Dentistry, Periodontology and Cariology , Center of Dental Medicine, University of Zurich , Zürich , Switzerland .
authors.forename: Thomas
authors.initials: T
authors.lastname: Attin
authors.affiliation: b Oral and Maxillofacial Unit , Tampere University Hospital , Tampere , Finland , and.
authors.forename: Timo
authors.initials: T
authors.lastname: Peltomäki
authors.affiliation: c Department of Statistics , University of Munich , Munich , Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Heumann
authors.affiliation: a Clinic of Preventive Dentistry, Periodontology and Cariology , Center of Dental Medicine, University of Zurich , Zürich , Switzerland .
authors.forename: Patrick Roger
authors.initials: PR
authors.lastname: Schmidlin
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000293:Adolescent; D002516:Ceramics / Q000737:chemistry; D004396:Coloring Agents; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods; D003737:Dental Cavity Preparation / Q000145:classification; D003763:Dental Leakage / Q000145:classification*; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000145:classification*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005740:Gases / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000648:ultrastructure; D010539:Permeability; D011312:Pressure; D011897:Random Allocation; D012394:Rosaniline Dyes; D013314:Stress, Mechanical; D013696:Temperature; D014867:Water / Q000737:chemistry; D055815:Young Adult
chemical_list: D004396:Coloring Agents; D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D005740:Gases; D012394:Rosaniline Dyes; D014867:Water; C023506:Glass ceramics
keywords: Thermodynamic loading; leakage; marginal analysis; restoration