The relationship between Universal Dental Anchorage System (UDA) pins and the dental pulp chamber, in vitro.

PURPOSE OF STUDY: 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. CONCLUSION: The results suggest that the use of 2.1 mm UDA pins would, in many cases, represent a risk to pulpal health.