title: The relationship between Universal Dental Anchorage System (UDA) pins and the dental pulp chamber, in vitro.
abstract: OBJECTIVE
  The Universal Dental Anchorage (UDA) System incorporates the use of pins inserted into enamel and dentine to retain a pontic. The pins are placed horizontally into teeth in the region of the contact area and so are potentially placed close to the dental pulp. This study aims to investigate and measure this relationship to assess if the pulp may be placed at risk during pin hole preparation or UDA pin placement.
  
  
  METHODS
  Teeth were assessed radiographically and pins placed according to manufacturer's instructions. The teeth were subsequently sectioned through the pin position and measurements from the pin tip to the pulp chamber made at 4X magnification.
  
  
  RESULTS
  In the majority of the teeth the pins were in close proximity to the pulp chamber (mean +/- sd = 0.8 +/- 0.7 mm). Two pins were in direct communication with the pulp chamber. Seven pins were separated from the pulp chamber by only 0.1-0.5 mm and six pins by 0.6-1.0 mm. Three pins were more than 1.0 mm from the pulp chamber.
  
  
  CONCLUSIONS
  The results suggest that the use of 2.1 mm UDA pins would, in many cases, represent a risk to pulpal health.
authors.affiliation: Department of Conservative Dentistry, King's Dental Institute, London.
authors.forename: S
authors.initials: S
authors.lastname: Dunne
authors.forename: B
authors.initials: B
authors.lastname: Millar
mesh_terms: D000328:Adult; D003722:Dental Alloys; D003772:Dental Pins / Q000009:adverse effects; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging; D003779:Denture Design; D003781:Denture Retention / Q000295:instrumentation* / Q000379:methods; D003830:Denture, Partial, Fixed; D006801:Humans; D066298:In Vitro Techniques; D011859:Radiography; D012307:Risk Factors; D014025:Titanium; D019231:Tooth Preparation, Prosthodontic
chemical_list: D003722:Dental Alloys; D014025:Titanium