title: Remaining dentine thickness and human pulp responses.
abstract: OBJECTIVE
  To evaluate pulp responses as a function of remaining dentine thickness (RDT) of 98 class V cavity preparations in 49 teeth of 31 patients aged 10-16 years.
  
  
  METHODS
  Shallow cavities were restored with amalgam, deeper cavities or pulp exposures were restored with amalgam lined with calcium hydroxide or with zinc oxide eugenol. Teeth were extracted after 3-89 days for orthodontic reasons. Following processing for light microscope analysis, the number of odontoblasts, pulp inflammation, and repair was recorded.
  
  
  RESULTS
  In comparison with independent odontoblasts, the numbers of odontoblasts were reduced by 13.6% beneath a RDT of 2.5-0.5 mm, 33.7% beneath a RDT of 0.5-0.01 mm and 99.0% beneath pulp-exposed cavities. Reparative dentine was observed following pulp exposure and reactionary dentine was observed with a mean RDT of 0.77 mm (2.5-0.01 mm). Reactionary dentine secretion was influenced by RDT and restorative materials. Pulp inflammation was not influenced by RDT in the present study.
  
  
  CONCLUSIONS
  Cavity RDT mediates a powerful influence on underlying pulp tissue vitality but it has little effect on reactionary dentine secretion and inflammatory activity. Gross tissue injury explains the poor pulp capping prognosis following exposure and underlies the need to avoid this type of injury. Following restoration, a RDT of 0.5 mm or greater is necessary to avoid evidence of pulp injury.
authors.affiliation: Oral Biology Indiana University School of Dentistry, Indianapolis, IN 46202, USA. petmurra@iupui.edu
authors.forename: P E
authors.initials: PE
authors.lastname: Murray
authors.forename: A J
authors.initials: AJ
authors.lastname: Smith
authors.forename: L J
authors.initials: LJ
authors.lastname: Windsor
authors.forename: I A
authors.initials: IA
authors.lastname: Mjör
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002126:Calcium Hydroxide / Q000009:adverse effects; D002452:Cell Count; D002648:Child; D003737:Dental Cavity Preparation / Q000009:adverse effects*; D003793:Dental Restoration, Permanent / Q000009:adverse effects; D003804:Dentin / Q000033:anatomy & histology*; D003809:Dentin, Secondary / Q000254:growth & development / Q000378:metabolism*; D006801:Humans; D009804:Odontoblasts / Q000378:metabolism; D011671:Pulpitis / Q000209:etiology*; D012044:Regression Analysis; D015035:Zinc Oxide-Eugenol Cement / Q000009:adverse effects
chemical_list: D015035:Zinc Oxide-Eugenol Cement; D002126:Calcium Hydroxide