Attachments

ATTACATTACHH HHMENTSMENTS

IN

PROSTHESES

Clasp assembly

• Rest

• Retentive arm

• Stabilizing (bracing) and reciprocation arm

• Proximal plate

Direct retainer

Intracoronal A.

Extracoronal A.

Clasps

AttachmentsPrecision Semi precision

SuprabulgeInfrabulge

Retainers

Definition• Attachment : is a mechanical device which contributes to the retention stabilization support of a dental prosthesis.

Key...........Keyway

Male..........Female

Patrix........Matrix

Flange......Slot

Attachment application

Crown & Bridge (FPD)

Partial Denture (RPD)

Overdenture (tooth & implant)

Attachments classification

Location

Function

Retention

Cost & accuracy

Adjustability

1-Intracoronal A.

2-Extracoronal A.

3-Anchor/Stud A. (Radicular / Intraradicular)

4-Bar Clip A.

5-Auxiliary A.


Location

Function

Retention

Cost & accuracy

Adjustability

1- Rigid / Solid - Class 1a , rigid

- Class 1b , rigid with lock

2- Resilient - class 2 , vertical

- class 3 , hinge

- class 4 , vertical & hinge

- class 5 , rotational & vertical

- class 6 , universal


Location

Function

Retention

Cost & accuracy

Adjustability

1-Frictional

2-Mechanical

3-Frictional & mechanical

4-Magnetic

5-Suction


Location

Function

Retention

Cost & accuracy

Adjustability

Precision

Semi-precision


Location

Function

Retention

Cost & accuracy

Adjustability

Adjustable

Non-adjustable

Criteria for selection:• Location • Inter-occlusal space (5 mm)• Size & bulk & shape• Type of retention • Type of function• Type of prostheses (FPD or RPD)• Possibility of adjustment & repair• Cost• Easy to plaque control• Abutment• Ability of patient

Attachments selection


Space :

Intracoronal attachments (Connector & Retainer)

Properties:• Incorporated entirely within the contour of the crown• Occlusal forces applied close to the axis of rotation• Available space = tooth size• All intracoronal attachments are non-resilient• Various cross section• Recommend double abutting• Extensive preparation of abutment• Easy to maintain hygiene

Extracoronal attachments ( Retainer)

Properties:• Positioned entirely outside the crown contour• Normal tooth contour can be maintained• Difficult to maintain hygiene• Minimal tooth reduction is necessary• Possibility of devitalizing a tooth is reduced• Most have some type of resiliency• Even with resilient attachment double abutting is recommended• As a stress breaker and stress director in free end RPD

Anchor/Stud attachments ( Retainer)

Properties:• Used in overdenture cases• Solder or cast to a root cap coping• Directly cemented into a prepared root• Using with implant• Promote better oral hygiene• Crown-root ratio is enhanced• Both rigid or resilient forms are available• Ball and socket movement

Bar clip attachments ( Retainer)

• Properties:• Used in overdenture cases• Span an edentulous area and connect abutment teeth, roots or implants• Solder or cast to a root cap coping• Anterior-posterior movement• Both rigid or resilient forms are available• Promote better oral hygiene• Crown-root ratio is enhanced

Rigid attachments :Indications:• No vertical movement is anticipated• Only for tooth supported prostheses• Need to strong abutments• Functioning against complete denture or resilient overdenture• Large well fitting denture base to distribute forces of occlusion• Inter-occlusal space is limited

Resilient attachments :Indications:

• Tissue-tooth supported prostheses

• Weak abutments, when maximum tissue support is required

• Only a few abutments

• Functioning opposite natural dentition

• Functioning against non-resilient appliance

• Multi-directional action is desired

• With minimal denture base• As a stress breaker and stress director in free end RPD

Advantages• Ease of insertion and removal• Simple laboratory work & economic cost• Reduced lateral forces• No leverage• No fragile parts for fracture• No activation necessary• Do not need special equipment (parallelometer) • Easy to maintain oral hygiene

Magnetic attachments ( Retainer)

Auxiliary attachments :Properties:• Usually with other attachments for increasing retention• Small size• Complex laboratory procedure• Difficult to maintain oral hygiene

Surveyor & parallelometer

•Path of insertion •Force control•Esthetic consideration•Biologic tooth contour•Elimination of interferences

Overdenture & attachment maintenance problems

• Tooth decay & Copings loosening• Attachment wear & breakage• Alveolar resorption• Overdenture breakage• Pt. maintenance problems• Pt. oral hygiene problems

موفق باشید

Precision Attachments• Machined in special alloys• Precise tolerances• Less wear• Interchangeable• Easier to repair

Semi-Precision Attachments• Direct casting of plastic, wax or refractory patterns• Injection molded• Components vary to a small degree• Less cost, Ease of fabrication• Ability to cast in wide choice of alloys


ATTACHMENT CLASSIFICATION-FUNCTION

Rigid/Solid Attachment: No movement is possible between the parts. Usually used in situations where the abutment teeth fully support the restoration and attachment: the soft tissues do not give support.

Resilient Attachment:Allows movement to take place between the matrix and patrix when fully seated, thus having a stress-breaking function. The movement is usually that of a hinge and serves to distribute potentially harmful forces away from abutment teeth in distal extension situations and where there are long edentulous spans.

Advantages:• Elimination of visible clasp armsDisadvantages:• Additional expense• Increased frequency of adjustment and failure• Increased technical expertise required• Unpredictable or unfavorable distribution of forces

RPD & attachments

Attachments

Health & Medicine

Transcript of Attachments