BY : DR. Nora cheta

Intracoronal attachments

Extracoronal attachment

CLASP ASSEMBLY Retentive arm Bracing arm Occlusal rest Minor connector

SURVEY LINE UNDERCUT AREA NON UNDECUT AREA HEIGHT OF CONTOUR Carbon Marker

DESIRABLE UNDERCUT NON DESIRABLE UNDERCUT UNDERCUT GAUGE

DESIRABLE UNDERCUT NON DESIRABLE UNDERCUT

Types of Survey Line Near the saddle Away from the saddle

A-MEDUIM SURVEY LINE Midway between Occlusal surface & Gingival margin in the Near zone Nearer to gingival margin In the far zone We can use occlusally or gingivally approaching clasps

B-DIAGONAL SURVEY LINE Near occlusal surface In the near zone Near gingival margin In the far zone Or Back action & Reverse back C clasp Ging.app. With T bar Ging.app. With L bar

C-HIGH SURVEY LINE Near to the occlusal surface Wrought wire occlusally app. Back action or reverse back action commonly in inclined teeth Bracing Arm

TILTING THE TOOTH BUCCALLY SENDS THE SURVEY LINE MORE OCCLUSALLY!! BUCCAL

TILTING THE TOOTH LINGUALLY SENDS THE SURVEY LINE MORE CERVICAL!! LINGUAL

D- LOW SURVEY LINE Near the gingival margin Extended arm clasp Devan clasp engaging proximal undercut Crowning of the tooth

REQUIREMENTS OF CLASP DESIGN. Bracing arm better located In the apical portion of the Middle 1/3 Retentive arm better located In the gingival 1/3 for better esthetics & mechanics

UNDERCUT IS BETTER BE FOUND WITHIN THE GINGIVAL1/3 For mechanical reasons Post Is More Readily Removed by Application of Force Near Its Top Than by Applying Same Force Nearer Ground Level

RECOPRICATION

Each retentive terminal should be reciprocated as retentive arm exerts some orthodontic movement during placement and removal as it flexes about the height of contour.

BRACING

THE DIFFERENCE IS!!!!! RECOPRICATION IS TO PREVENT THE NATURAL TOOTH MOVEMENT. BRACING IS TO PREVENT THE WHOLE DENTURE MOVEMENT. BOTH ARE APPLIED USING THE SAME COMPONENT BRACING ARM-----

OCCLUSAL 1/3, FOR SUPPORT MIDDLE 1/3, FOR BRACING &RECOP. GINGIVAL 1/3, FOR RETENTION.

180 degrees ENCIRCLEMENT OF THE TOOTH. Tooth can't move horizontally away from the clasp

Amount of retention depends on The greater the distance we go into the undercut the greater will be the retention A- depth of undercut

2. FLEXIBILITY OF CLASP ARM LENGTH Increasing arm length increases the flexibility,thus decreasing the retention

SHAPE OF THE CLASP CROSS SECTION Round clasps have universal flexibility thus lowers the retention than ½ round and flat clasps

Degree of taper Retentive arm should be tapered in two dimensions.

The diameter of retentive arm The material of the alloy (gold alloy are more flexible than cobalt chrome alloy ) The type of alloy (wrought wire

C- Angle of cervical convergence

Occlusally approaching clasp Gingivally approaching clasp Clasps according to method of approach to undercut

1-Akers clasp (circlet)

2-DOUBLE AKER (embrasure) LINGUAL BUCCAL

CROSS ARCH STABILISATION!!

3-CIRCUMFERENTIAL `C` CLASP

B-DIAGONAL SURVEY LINE Near occlusal surface In the near zone Near gingival margin In the far zone Or Back action & Reverse back C clasp Ging.app. With T bar Ging.app. With L bar

4-R.P.A, REST, PROXIMAL PLATE,AKER.

5- Multiple clasp

6- Extended arm clasp Abutment has no undercut Adjacent tooth has a reasonable undercut

D- LOW SURVEY LINE Near the gingival margin Extended arm clasp Devan clasp engaging proximal undercut Crowning of the tooth

7- Half & Half clasp 2 M.C., 2 O.R. & 2 arms. Mainly indicated for dual retention commonly in unilateral cases.

SINGLE ARM CLASPS!!! THESE ARE FLEXIBLE CLASPS, DUE TO THEIR ELONGATED SINGLE ARM, AND THEY PROVIDE POOR BRACING.

7-RING CLASP (ISOLATED, BADLY LINGUALLY TILTED, LOWER MOLAR.)

Buccal Lingual Distal Mesial Strut arm

8-Reverse Back action clasp. (MANDIBULAR) M.C. originating Mesio-buccally Retentive arm engage Mesio-lingual undercut

9-Back action clasp. (MAXILLARY) Single arm clasp Minor connector starts mesio- lingually It engages mesio-buccal undercut. O.R. is located distally. Used in free end saddle. Distal. Mesial

T clasp Modified T clasp Different forms of gingivally approaching clasps I clasp

Contraindications for the use of gingivally approaching clasps

TISSUE UNDERCUT.

TRIPPING ACTION!!!!

OCCLUSALLY APP. ARE PULLED OUT. GING. APP. ARE PUSHED. (TRIP. ACTION).

R.P.I REST, PROXIMAL PLATE, I-BAR The base of the I bar Should be 3mm away From the gingival margin

Combination clasp Gingivally app. Retentive arm (buccally) & Occlusally app. Bracing arm (lingually)

Buccal wrought wire retentive arm soldered to the base Lingual casted bracing arm COMBINATION CASTED & WROUGHT WIRE CLASP.

SO WHAT DID WE LEARN??????

Clasps with splinting action Double Aker clasp Extended arm clasp Multiple Aker clasp

Clasps used in free end saddle cases.(class I&II) All gingivally approaching clasps. Occlusally approaching clasps – Reverse Aker clasp – Back action clasp – Reverse back action clasp – R.P.A. Combination clasps ( 2 types).

Occlusally Gingivally Retention due to tripping action Bracing aAbove survey line provide bracing. Esthetics less visible due to gingival position Tolerance Gingivally app.clasp arm relieved from gingiva creating space accumulating food and causing discomfort. Caries More tooth coverage increasing the risk for caries Gingival health Trauma may occur due to distortion or inadequate relief

Consideration for Clasps in Free End Saddle Cases!!!!

THE PROBLEM OF THE FREE END SADDLE IS DISPARITY OF SUPPORT!!!!!!

MOVEMENT OF CLASP CAUSES TORQUEING.

WHAT DO WE DO????

NO. 1: USE FLEXIBLE CLASPING.

Clasps with stress breaking action (class I&II) All gingivally approaching clasps. Occlusally approaching clasps – Reverse Aker clasp – Back action clasp – Reverse back action clasp Combination clasps ( 2 types).

WROUGHT WIRE CLASP DURING FUNCTION

NO 2: PLACE OCCLUSAL REST MESIALLY.

CLASS 1 LEVER.

CLASS 2 LEVER.

DISENGAGEMENT FROM THE UNDERCUT.

NO 3: DISTRIBUTE THE LOAD.

NO 4: VARY THE CONNECTION BETWEEN D.BASE AND THE RETAINER.

NO 5: RECORD THE RIDGE IN FUNCTIONAL FORM.

To reduce the denture base movement, record the ridge in compressed form (functional form.)