title: Effect of cavity depth on dentine sensitivity in man.
abstract: OBJECTIVE
  To determine if dentine at the enamel-dentine junction (EDJ) in man is more sensitive to hydrostatic pressure stimuli then deeper dentine.
  
  
  METHODS
  Cavities (1mm diam.) were cut at the tips of the buccal and lingual cusps of 8 premolars in 3 subjects (ages: 22-25 years). Both cavities were initially deepened to expose the EDJ then one (the test cavity) was deepened in steps of 0.5mm to a maximum of 2.0 mm below the EDJ. The cavities were tested at each stage, before and after etching, with 5s, hydrostatic pressure stimuli between 400 mm above, and 400 mm below atmospheric. The intensity of any pain produced was recorded on a VAS scale and electrodes were placed in both cavities in an attempt to monitor any action potentials evoked in intradental nerves.
  
  
  RESULTS
  In all the teeth, the intensity of the pain produced by a stimulus tended to increase as the cavity was deepened, as did the number of action potentials recorded (in 6 of the 8 teeth). The responses were greater from etched than unetched dentine, and negative pressures evoked greater responses than the corresponding positive pressures.
  
  
  CONCLUSIONS
  There was no evidence that dentine close to the EDJ was more sensitive to hydrostatic pressure stimuli than deeper dentine. It may however be more sensitive to mechanical stimuli as it is more compliant.
authors.affiliation: Department of Oral Biology and Oral Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Chiang Mai 50202, Thailand.
authors.forename: Sitthichai
authors.initials: S
authors.lastname: Wanachantararak
authors.affiliation: Department of Stomatology, Faculty of Dentistry, Srinakharinwirot University, Bangkok 10500, Thailand.
authors.forename: Orapin
authors.initials: O
authors.lastname: Ajcharanukul
authors.affiliation: Department of Oral Biology, Faculty of Dentistry, Mahidol University, Bangkok 10400, Thailand. Electronic address: noppakun.von@mahidol.ac.th.
authors.forename: Noppakun
authors.initials: N
authors.lastname: Vongsavan
authors.affiliation: Department of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK.
authors.forename: Bruce
authors.initials: B
authors.lastname: Matthews
mesh_terms: D000134:Acid Etching, Dental; D000328:Adult; D001274:Atmospheric Pressure; D001641:Bicuspid; D003737:Dental Cavity Preparation / Q000009:adverse effects*; D003743:Dental Enamel / Q000033:anatomy & histology / Q000503:physiopathology; D045662:Dental Etching / Q000009:adverse effects; D003804:Dentin / Q000033:anatomy & histology / Q000503:physiopathology; D003807:Dentin Sensitivity / Q000139:chemically induced / Q000503:physiopathology*; D006801:Humans; D006874:Hydrostatic Pressure; D008297:Male; D010146:Pain / Q000209:etiology / Q000503:physiopathology; D017288:Pain Threshold / Q000502:physiology; D019228:Tooth Crown
keywords: Enamel-dentine junction; Pain