elements of removable partial dentures

Elements of removable partial dentures(Frank Kaiser)

A removable partial denture is a metallic structure supporting artificial teeth,destined to recover the six following oral functions: chewing, aesthetic, phonetic, weakenedtooth stabilization, prevention of inclination migration or drawing of remaining teeth,muscular balance in the face.

Clasps

Without making difficult the voluntaryremoval of the prosthetic, the clasps musthave enough retention to avoid thedislocation of the prosthetic duringfunctional efforts.Three measuring instruments can be usedto calibrate the retention:

1 – 0.01"2 – 0.02"3 – 0.03"

Types of clasps:

- Circumferential clasps- Simple (Ackers)- Ney n°1- Twin (Bonwill)- Back-action (Nally Martinez)- M.D. (Equipoise)

- Bar clasps- Roach (T)- R.P.I.

- Ney n°2- Diverse clasps - Contention - Kennedy clasp

Attention: Not to confuse the anatomicalequator of the tooth (bigger contour) withthe prosthetic equator (equator in relationbetween all the teeth).

The opposition clasps (without retention)are indicated for all the types of retentionclasps.

The indication of the type of clasp to beused depends on the size and thelocalization of the toothless spaces, thedegree of inclination and the availableretention of the teeth.

The volume of the muscular insertions, theaesthetic and the comfort of the patientare also determinative.

Rests

The function of the rests is to assure that apart or the totality loads exerted on theartificial teeth during chewing aretransmitted to the support teeth. They arealways connected to the minor connectors,and have a function of protection from thepapillas against crushing.

Types of rests :- Oclusal rest

- Simples- Double- Twin

- Cingulum rest- Incisal rest- Macro rest

WrightWrong

The ideal form of the simple clasp:In tip - Half Moon

The dentist makes the preparation in themouth, destined to receive the rest. Thedirect rests are located directly to the sideof the prosthetic spaces. The indirect restsare located distant to the prostheticspaces.Location of the rests:

Saddles

The saddles are the elements of the partialdenture destined to fill the prostheticspaces, to support and to join the artificial

teeth between them. They also have afunction of transmission of the masticatoryforces to the gingival.

Minor connectors

Besides joining the rests and the clasps to

the saddles and the major connectors, theyare also a transmission path for the oclusalloads to the support teeth. The direct minorconnectors are located directly to the side

of the prosthetic spaces. The indirect minorconnectors are located the distant to theprosthetic spaces.

Major connectorsThey are the elements in charge to connectthe other components of the prostheticbetween them, in the way to constitute asingle body. The major connector can becompared to the frame of a car,guaranteeing the rigidity and the goodfunctioning of all parts of the vehicle.

Types of major connectors:

- Lingual bar:

The lingual bar will be discharge 0.01" offthe gingival (0.02" free ends cases).

- Palatine plate:Anterior and posterior stabilization wingscan be added in the palatines plates,

improving the stability of the prosthetic,creating an indirect retention.

- Dental major connector:The dental major connector is a solution forhigh lingual insertions, presence of torus,or little height.

Frank KaiserTel. +55 (41) 9972-0304www.dentalstrategy.com

They also have aremaining teethstabilization function,and they are a guidefor the partial duringits insertion.