prosthesis

1. FREE END SADDLE DESIGN (CLASS 1 , 2)
Types of Movements that can occur Resisted by
Rotation about fulcrum line Indirect retainer , Retentive clasp arms
maximum extension of denture base
Rotation about longitudinal axis as distal extension base
moves in rotary fashion about the residual ridge
Rigid major and minor connectors
maximum extension of denture base
Rotation about vertical axis near center of arch reciprocal arms and minor connectors)
Horizontal forces during function as mastication , bruxing ,
clenching
Best resisted by constructing an occlusal scheme that is
harmonious with the rest of the natural teeth
Support Composite support  from teeth and residual ridge
Denture base Combined maximum extended saddle provide retention , support , stability
Direct retainer RPI 0.01 mid facial under cut Mesial rest
Modified T-bar 0.01 disto facial under cut Mesial rest
Reverse Aker clasp 0.01 disto facial under cut Mesial rest
Combination clasp 0.02 mesio facial under cut (Wrought wire arm) Distal rest
Rest Primary occlusal rest should be Saucer shaped to distribute lateral force in abutment
Indirect retainer placed on a tooth as far anterior, as possible to fulcrum line  can be placed on
upper central incisors , upper canines , lower canines
Major connector Mandibular major connectors :
 lingual bar is preferred (8 mm space should be available)
 less than 8 mm or teeth are questionable  lingual plate
maxillary major connector :
 antroposterior palatal bar or strap - complete palatal coverage
 if there is torus  horseshoe connector
Stress breaker By using type of the 4 clasps above
Class 2 mod 1 As class 2 plus :-
Clasps for Isolated molar 
1. aker clasp if there is disto ficial or disto lingual undercut
2. ring clasp if there is mesio facial or mesio lingual undercut
 maxillary molar  mesio facial undercut …… mandibular molar  mesio lingual undercut
 tilted molar  2 rest …… upright molar  1 rest
 large molar  need reinforcing arm …… small molar  no reinforcing arm
3 clasps are required in class 2 mod 1 :
 2 clasps in primary abutment teeth (in dentulous side)
 1 clasp in secondary abutment tooth (in edentulous side)  to provide retention of RPD
against tissue ward movement (masticatory forces) , look picture 1 , this secondary
abutment tooth has also any form of indirect retainer to provide retention of RPD against
tissue away movement (sticky food) look picture 2
Design
PROSTHEASY

2. Class 3
Support From only abutment teeth
Denture base Solid metal denture base  due to low probability of ridge resorption that require future
relining
Combined  if the teeth are questionable and there is predication that bounded saddle convert
to free end saddle
Direct retainer 4 clasps should be placed for quadrilateral design in case of modification of class 3
Clasps can be used 
 Cast circumferential (aker) is the clasp of choice
 For isolated tooth  aker or ring clasp
Direct retainers are placed so that retentive tips are as far away from each as possible
Movement Class 3 has 2 fulcrum line (anterior and posterior)  RPD could try to lift up and rotate around
anterior fulcrum line or posterior fulcrum line  this is resisted by clasping mechanism on each
abutment nexto to the edentulous area
Rest Box shape occlusal rests or cingulam rests may be used for maxillary canines
Major
connector
Maxillar  palatal bar – balatal strap – antroposterior palatal strap
If torus  horseshoe connector
Mandiblar  lingual bar or lingual plate
Indirect retainer No need for indirect retainer because there is no extension base and quadrilateral design
(clasping mechanism ) provide this indirect retention
Stress breaker No need for stress breaker as We do not have to worry about torque forces being applied to
abutment teeth in tooth supported RPD because of clasping mechanism provided
Class 4
In case of short edentulous span  need for direct and indirect retainers are limited
In case of long span edentulous span 
 4 clasps can be used for quadrilateral design
 Indirect retainer to be placed posterior to fulcrum line (occlusal rests on posterior teeth )
Denture base Should be combined to provide esthetic
Direct retainer Aker or double aker (Embrasure clasp)
Rest Occlusal rest for aker clasp
Embrasure rest (inter occlusal rest) for Embrasure clasp
Also cingulam rests may be used for maxillary canines
Major connectors Maxillar  palatal bar – balatal strap – antroposterior palatal strap
If torus  horseshoe connector
Mandiblar  lingual bar or lingual plate
Indirect retainer No need for indirect retainer because Occlusal or embrasure rests in posterior teeth
provide this indirect retention
Stress breaker No need for stress breaker
PROSTHEASY