Attachments and their use in RPD fabrication....ppt download

A lecture note on Attachments and their use in RPD fabrication

.What is an attachment?

An attachment is a connector consisting of two or more components.  One component is connected to a tooth, tooth root, or an implant and the other component is connected to a prosthesis.

Types of Attachments

Intracoronal  Attachment

Intracoronal attachments are incorporated entirely within the contour of the crown.  The advantage of an intracoronal attachment is that the occlusal forces exerted upon the abutment tooth are applied close to the long axis of the tooth.  A disadvantage arises when the abutment is overcontoured by placing the “intracoronal attachment” outside the crown contour.  This often results from insufficient tooth reduction.  It it is not possible to create a box preparation that will totally incorporated the female element, then an extracoronal attachment should be considered.  These attachments are non resilient.  When limited space exists, a miled lingual surface should be provided on the crown.  Most wear occurs on these attachments during placement and placement.

Extracoronal Attachment

Extracoronal attachments are positioned entirely outside the crown contour of the tooth.  The advantages of this type of attachment are that the normal tooth contour can be maintained, minimal tooth reduction is necessary and the possibility of devitalizing the tooth is reduced.  Also, the path of insertion is easier for patients with limited dexterity.  It is more difficult to maintain hygiene with extracoronal attachments and patients need to be instructed on the use of hygiene accessories such as proxi brushes etc.  Keeping the underside of the attachment area clean, greatly improves the tissue response.