slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Principles of bridge construction PowerPoint Presentation
Download Presentation
Principles of bridge construction

Loading in 2 Seconds...

play fullscreen
1 / 23

Principles of bridge construction - PowerPoint PPT Presentation


  • 227 Views
  • Uploaded on

Principles of bridge construction. Biomechanical Considerations. These include the role of the edentulous span dimensions, the pontic characteristics and the connectors or joints of the bridge components on the success of the constructed bridge.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Principles of bridge construction' - athena-juarez


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Principles of bridge

construction

biomechanical considerations
Biomechanical Considerations
  • These include the role of the edentulous span dimensions, the pontic characteristics and the connectors or joints of the bridge components on the success of the constructed bridge.
slide3
The span, represent the edentulous space that will be occupied by the pontic.
  • The dimensions of the span (mesio-distal length and occluso-gingival height) were found to influence the number of the selected abutments, the type of retainers and the material from which the bridge will be constructed.
slide4
All bridges either short or long flex or bend to some extent due to forces applied through the pontics to the abutment teeth
  • Bending or flexing of the bridge under these forces was found to:

a.Vary directly with the cube of the span length (p).

b.Vary inversely with the cube of the occluso-gingival thickness (T)

slide9
To minimize the flexion or deflection of the long or thin spans:-
  • Select pontic designs with a greater occluso gingival dimension.
  • The prosthesis may also be fabricated of an alloy with higher yield strength as nickel chromium.
  • Secondary abutments carefully selected may be used.
slide10

Torque force

  • Longer spans also have the potential for producing more torquing or displaying forces on the bridge especially on the secondary abutment.
slide11

The forces on the retainers of bridges are different in magnitude and direction from those applied to single restorations, the dislodging forces on a bridge retainer tend to act in a mesio-distal direction, compared to the more common buccolingual direction of forces on a single restoration.

slide12
The preparation should be modified to produce greater resistance and structural durability for ex. multiple grooves, including some of the buccal and lingual surfaces.
slide13
The most effective location of the groove to resist torque is in a plane perpendicular to the axis of torque. The load on the long span bridge with straight pontics produces torque around bucco-lingual axes. Resistance can be best enhanced by the addition of buccal and lingual grooves.
slide14

The load on the pontic that lies buccal to the interabutment axis line produces torque primarily around that axis. The most effective location for supplemental grooves in this situation is on the mesial and distal surfaces.

slide15

Pressure on a cantilevered pontic produces a strong lifting force on the distal retainer. Resistance can be increased by adding buccal and lingual grooves, and by making the most distal axial surface as nearly as parallel with the wall nearest from the pontic as possible.

arch curvature
Arch curvature

when the pontic lies outside the inter-abutment axis line, the pontic act as a lever arm, which can produce a torquing movement. This is a common problem in replacing all four maxillary incisors with a bridge.

To compensate this torque, additional retention is required in the opposite direction from the lever arm and at a distance (R) from the inter-abutment axis equal to the length of the pontic lever arm (p)

slide17

Secondary retention(R)must extend a distance from the primary inter-abutment axis equal to the distance that the pontic lever arm(P)extends to the opposite side

special problems
Special problems

Pier abutments

special problems1
Special problems

Tilted molar abutments

special problems2
Special problems

Canine-Replacement fixed partial denture

The forces are directed more outward and the pontic lies farther outside the inter-abutment axis

The forces are directed inward and the pontic is closer to the interabutment axis

special problems3
Special problems

Cantilever fixed partial denture