title: Intracanal molar barometric pressure differentials at simulated altitude conditions - proof of concept study.
abstract: OBJECTIVE
  To evaluate whether objective data could be obtained regarding internal pressure conditions of a molar tooth with canals prepared but not filled exposed to reduced barometric pressures that could be experienced by aircrew.
  
  
  METHODS
  The root canals of five mandibular molars were prepared but not filled. Root apices were sealed with a resin-modified glass-ionomer liner and root surfaces sealed with a dental adhesive. The sealed root surfaces were then coated with a polyvinylsiloxane (PVS) adhesive and the teeth inserted into cylinders of PVS impression material to the level of the cervical enamel junction. Barometric pressure transducers were placed in the pulp chambers with the endodontic access sealed with cotton and a provisional restoration. The specimens were then subjected to a manually controlled, atmospheric altitude challenge consisting of a slow ascent and descent to a simulated 25 000 feet above sea level followed by a rapid altitude climb and descent. The real-time difference between intracanal and simulated atmospheric pressures were recorded and correlated (Pearson's, P = 0.05).
  
  
  RESULTS
  No tooth material fractured, and there was no failure of the provisional restorations. Barometric pressures inside the closed prepared molar canals and the ambient atmospheric pressure were found to correlate (r(2)  = 0.97-0.99; P < 0.0001), but pressure equalization lags were observed. However, no differences greater than six pounds per square inch (310 torr) were noted.
  
  
  CONCLUSIONS
  This pilot study established a protocol that demonstrated that objective data regarding barometric pressures within the prepared canals of molars can be obtained at simulated altitude conditions.
authors.affiliation: Graduate Dental Research/Graduate Program in Endodontics, Keesler Air Force Base, Biloxi, MS, USA.
authors.forename: H W
authors.initials: HW
authors.lastname: Roberts
authors.affiliation: Graduate Dental Research/Graduate Program in Endodontics, Keesler Air Force Base, Biloxi, MS, USA.
authors.forename: T C
authors.initials: TC
authors.lastname: Kirkpatrick
mesh_terms: D000337:Aerospace Medicine; D000401:Aircraft; D000531:Altitude; D001274:Atmospheric Pressure; D001469:Barotrauma; D003786:Dental Pulp Cavity / Q000502:physiology*; D006801:Humans; D008963:Molar / Q000502:physiology; D018915:Root Canal Preparation
keywords: barodontalgia; barometric pressure; intracanal barometric pressure