What is retentive undercut?
re·ten·tive un·der·cut. (rē-tentiv ŭndĕr-kŭt) The area of an abutment tooth surface suitable for placing a clasp to retain a removable prosthesis.
What is retentive clasp?
The part of the clasp assembly that enters an undercut for retention is frequently called the RETENTIVE CLASP ARM. An ATTACHMENT is a mechanical device for the fixation, retention, and stabilization of a prosthesis (Fig.
What is prosthodontic clasp?
(klasp), 1. A part of a removable partial denture that acts as a direct retainer or stabilizer for the denture by partially surrounding or contacting an abutment tooth.
In which area of the crown the retentive clasp tip should be placed?
7. Reciprocal elements of the clasp assembly should be located at the junction of the gingival and middle thirds of the crowns of abutment teeth. The terminal end of the retentive arm is optimally placed in the gingival third of the crown.
What is the function of the retentive arm?
Figure 7-2 A, Flexing action of the retentive clasp arm initiates medially directed pressure on the abutment teeth as its retentive tip springs over the height of contour.
What is soft tissue undercut?
soft tis·sue un·der·cut (sawft tishū ŭndĕr-kŭt) Inward notching at the residual ridge or soft tissue of a dental arch that would influence the form of a removable denture.
Which clasp is used in small undercut?
If mesiobuccal undercut is present – combination clasp is used, if distobuccal undercut is present – bar clasp is used. If bar clasp is contraindicated, a reverse circlet clasp is used.
What is Embrasure clasp?
Definition. A clasp that is used where no edentulous space exists: 1. A circumferential clasp that passes through the embrasures, with an occlusal rest and circumferential arms.
What is retentive arm?
re·ten·tive arm , retention arm. a flexible segment of a removable partial denture that engages an undercut on an abutment and is designed to retain the denture.
When do you use an Embrasure clasp?
Embrasure clasp This design is most frequently used in cases of unilateral edentulous span of an unmodified Kennedy Class II or Class III partial denture, on the side of the arch where there is no edentulous space.
What are undercuts in impression?
undesirable undercuts. Mosby’s Dental Dictionary defines an undercut as “the portion of a tooth that lies between its height of contour and the gingiva, only if that portion is of less circumference than the height of contour.” Undercuts exist because of natural tooth morphology and contours.
When is Embrasure clasp used?
The embrasure clasp is a clasp assembly used when there is no edentulous space near the clasp site. It is called an “embrasure” clasp because it emerges from an embrasure as it approaches the retentive area.
How much undercut should a Retentive clasp engage?
Occlusally-approaching retentive clasps should have the terminal third of the retentive arm entering the undercut. A retentive clasp should engage 0.25 mm of undercut if it is constructed in cast cobalt-chromium alloy.
What is the minimum length of a Retentive clasp?
If an undercut on a tooth that needs to be clasped for retention is less than 0.25 mm, then composite resin should be added to the tooth to create at least this amount of undercut. A retentive clasp should be at least 15 mm in length if it is constructed in cast cobalt-chromium alloy.
Where should a retentive occlusally-approaching clasp run?
A retentive occlusally-approaching clasp should run from the side of the tooth with the least undercut to the side with the greatest undercut. Occlusally-approaching retentive clasps should have the terminal third of the retentive arm entering the undercut.
How do you style a disconnected undercut on a man?
Otherwise, to style a disconnected undercut, the only difference is that you must comb your hair along the parted line between the top and sides of your undercut to accentuate the disconnect. Then, depending on whether you want a slick back or side part undercut, comb your hair straight back or angularly.