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, weakened tooth stabilization, prevention of inclination migration or drawing of remaining teeth, muscular balance in the face.

Clasps Without making difficult the voluntary removal of the prosthetic, the clasps must have enough retention to avoid the dislocation of the prosthetic during functional efforts. Three measuring instruments can be used to calibrate the retention:

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

Wright

Wrong

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

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

The indication of the type of clasp to be used depends on the size and the localization of the toothless spaces, the degree of inclination and the available retention of the teeth. The volume of the muscular insertions, the aesthetic and the comfort of the patient are also determinative.

Rests The function of the rests is to assure that a part or the totality loads exerted on the artificial teeth during chewing are transmitted to the support teeth. They are always connected to the minor connectors, and have a function of protection from the papillas against crushing.

Attention: Not to confuse the anatomical equator of the tooth (bigger contour) with the prosthetic equator (equator in relation between all the teeth).

Types of rests : - Oclusal rest - Simples - Double - Twin - Cingulum rest - Incisal rest - Macro rest

The dentist makes the preparation in the mouth, destined to receive the rest. The direct rests are located directly to the side of the prosthetic spaces. The indirect rests are located distant to the prosthetic spaces. Location of the rests:

Major connectors They are the elements in charge to connect the other components of the prosthetic between them, in the way to constitute a single body. The major connector can be compared to the frame of a car, guaranteeing the rigidity and the good functioning of all parts of the vehicle. Types of major connectors: - Lingual bar:

Saddles The saddles are the elements of the partial denture destined to fill the prosthetic spaces, to support and to join the artificial

The lingual bar will be discharge 0.01" off the gingival (0.02" free ends cases). - Palatine plate: Anterior and posterior stabilization wings can be added in the palatines plates,

teeth between them. They also have a function of transmission of the masticatory forces to the gingival.

Minor connectors Besides joining the rests and the clasps to the saddles and the major connectors, they are also a transmission path for the oclusal loads to the support teeth. The direct minor connectors are located directly to the side

improving the stability of the prosthetic, creating an indirect retention. - Dental major connector: The dental major connector is a solution for high lingual insertions, presence of torus, or little height.

of the prosthetic spaces. The indirect minor connectors are located the distant to the prosthetic spaces. They also have a remaining teeth stabilization function, and they are a guide for the partial during its insertion.

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