• INTRODUCTION:
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com
www.indiandentalac...
• In contrast with the Kratochvil’s basic design,
which necessitates heavy preparation, Krol
developed a modification that...
• The state emphasis in Krol’s system is stress
control with minimal tooth coverage and
minimal gingival coverage.
www.ind...
• The clasp system includes the three elements
of Kratochvil’s system: -
mesial rest,
proximal plate
and I-bar.
• Each ...
• In RPI system:
R = Rest
P = Proximal plate
I = I-bar
www.indiandentalacademy.com
REST
• Rest preparations are less extensive in the RPI
system.
• The mesial rest extends only into the
triangular fossa, e...
• Mesio occlusal rest with the minor connector
placed into the mesiolingual enbrassure, but
not contacting the adjacent to...
PROXIMAL PLATE:
• The proximal plate makes greatest departure
from Kratochvil’s design.
• The prepared guide plane is 2 to...
• . Relief is provided at the tooth – tissue
junction to allow the proximal plate to
disengage into the proximal undercut ...
• This proximal plate, in conjunction with the
minor connector supporting the rest, provides
the stabilizing and reciproca...
I – bar:
• The I-bar should be located in the gingival
thirds of the buccal or labial surface of the
abutment in a 0.001 i...
• The retentive tip contacts the tooth from the
undercut to the height of contour.
• This area of contact along with the r...
• There are three basic approaches to the
application of the RPI system.
• The location of the rest, the design of the
min...
• All advocate the use of a rest located mesially
on the primary abutment tooth adjacent to
the extension base area.
www.i...
I approach :
• This approach recommends that the guiding
plane and corresponding proximal plate minor
connector extend the...
• Bar clasp assembly in which guiding plane
(GP) and corresponding proximal plate (PP)
extend entire length of proximal to...
II approach:
• This approach suggests that the guiding plane
and corresponding proximal plate minor
connector extend from ...
• Both approaches recommend that the
retaining clasp arm be located in the gingival
third of the buccal or labial surface ...
• Bar clasp assembly in which guiding plane and
corresponding proximal plate extend from
marginal ridge to junction of mid...
III approach:
• This approach favours a proximal plate minor
connector that contacts approximately 1mm
of the gingival por...
• Bar clasp assembly in which proximal plate
contacts approximately 1 mm of gingival portion
of guiding plane .
• During f...
• Application of each approach is predicated on
the distribution of load to be applied to the
tooth and edentulous ridge.
...
• The stated purpose of reducing the proximal
plate is to improve gingival health by opening
up embrasure spaces as much a...
MODIFICATION TO RPI SYSTEM:
• Kroll in 1976 has given modification to RPI
system. That is
• RPA in which
R = rest
P = pr...
contraindications for a bar- type clasp
 exaggerated buccal or lingual tilts,
 severe tissue undercut
 or a shallow buc...
Tipped abutments
and tissue impingements are
• treated with RPA clasp.
• When Akers clasp arm is used, careful
attention...
The removable partial denture design:
british dental journal: vol-189; n0-7 pg-414
• In the study they concluded that ther...
10yr old eveluation of r.p.d’s ,survival rates
based in re treatment
j.p.d- vol-76: no-1, 1996
• In this survey 784 patien...
A randomised clinical trial of 2 basic r.p.d’s-
comparision of masticatory efficiency-
j.p.d- 1997: 78; 15-21
• Statement ...
conclusion
• Successful use of the system requires careful
analysis of each component for the function
that it provides an...
Thank you
For more details please visit
www.indiandentalacademy.com
www.indiandentalacademy.com
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Concepts new/ dental technician training online

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Indian Dental Academy: will be one of the most relevant and exciting

training center with best faculty and flexible training programs

for dental professionals who wish to advance in their dental

practice,Offers certified courses in Dental

implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic

Dentistry, Periodontics and General Dentistry.

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Concepts new/ dental technician training online

  1. 1. • INTRODUCTION: INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. • In contrast with the Kratochvil’s basic design, which necessitates heavy preparation, Krol developed a modification that avoids tooth preparation. www.indiandentalacademy.com
  3. 3. • The state emphasis in Krol’s system is stress control with minimal tooth coverage and minimal gingival coverage. www.indiandentalacademy.com
  4. 4. • The clasp system includes the three elements of Kratochvil’s system: - mesial rest, proximal plate and I-bar. • Each element, however, has undergone significant change to meet Krol’s criteria. www.indiandentalacademy.com
  5. 5. • In RPI system: R = Rest P = Proximal plate I = I-bar www.indiandentalacademy.com
  6. 6. REST • Rest preparations are less extensive in the RPI system. • The mesial rest extends only into the triangular fossa, even in molar preparations, and canine rests are often circular concave depressions prepared in the mesial marginal ridge www.indiandentalacademy.com
  7. 7. • Mesio occlusal rest with the minor connector placed into the mesiolingual enbrassure, but not contacting the adjacent tooth. www.indiandentalacademy.com
  8. 8. PROXIMAL PLATE: • The proximal plate makes greatest departure from Kratochvil’s design. • The prepared guide plane is 2 to 3 mm high occlusogingivally and the proximal plate contacts only 1 mm of the gingival portion of the guide plane www.indiandentalacademy.com
  9. 9. • . Relief is provided at the tooth – tissue junction to allow the proximal plate to disengage into the proximal undercut under occlusal loading. www.indiandentalacademy.com
  10. 10. • This proximal plate, in conjunction with the minor connector supporting the rest, provides the stabilizing and reciprocal aspects of the clasp assembly. www.indiandentalacademy.com
  11. 11. I – bar: • The I-bar should be located in the gingival thirds of the buccal or labial surface of the abutment in a 0.001 inch undercut. • The whole arm should be tapered into the terminus, with no more than 2 mm of its tip contacting abutment. www.indiandentalacademy.com
  12. 12. • The retentive tip contacts the tooth from the undercut to the height of contour. • This area of contact along with the rest and proximal plate contact provides stabilization through encirclement. • The horizontal portion of the approach arm must be located at least 4 mm from the gingival margin and even farther if possible. www.indiandentalacademy.com
  13. 13. • There are three basic approaches to the application of the RPI system. • The location of the rest, the design of the minor connector (proximal plate) as it relates to the guiding plane, and the location of the retentive arm are factors that influence how this clasp system functions. www.indiandentalacademy.com
  14. 14. • All advocate the use of a rest located mesially on the primary abutment tooth adjacent to the extension base area. www.indiandentalacademy.com
  15. 15. I approach : • This approach recommends that the guiding plane and corresponding proximal plate minor connector extend the entire length of the proximal tooth surface, with physiological tissue relief to eliminate impingement of the free gingival margin www.indiandentalacademy.com
  16. 16. • Bar clasp assembly in which guiding plane (GP) and corresponding proximal plate (PP) extend entire length of proximal tooth surface to contact greater surface area of guide plane which directs functional forces in horizontal direction , thus tooth {teeth} are loaded more than edentulous ridge. www.indiandentalacademy.com
  17. 17. II approach: • This approach suggests that the guiding plane and corresponding proximal plate minor connector extend from the marginal ridge to the junction of the middle and gingival thirds of the proximal tooth surface www.indiandentalacademy.com
  18. 18. • Both approaches recommend that the retaining clasp arm be located in the gingival third of the buccal or labial surface of the abutment in a 0.001 inch undercut www.indiandentalacademy.com
  19. 19. • Bar clasp assembly in which guiding plane and corresponding proximal plate extend from marginal ridge to junction of middle and gingival thirds of proximal tooth surface. • This decrease amount of surface area contact of proximal plate on guide plane more evenly distributes functional force between tooth and edentulous ridge www.indiandentalacademy.com
  20. 20. III approach: • This approach favours a proximal plate minor connector that contacts approximately 1mm of the gingival portion of the guiding plane and retentive clasp arm located in a 0.001 inch undercut in the gingival third of the tooth at the greatest prominence or to the mesial away from the edentulous area www.indiandentalacademy.com
  21. 21. • Bar clasp assembly in which proximal plate contacts approximately 1 mm of gingival portion of guiding plane . • During function, proximal plate and I-bar clasp arm are designed to move in mesiogingival direction, disengaging tooth. Lack of sustained contact between proximal plate and guide plane distributes more functional force to edentulous ridge. • www.indiandentalacademy.com
  22. 22. • Application of each approach is predicated on the distribution of load to be applied to the tooth and edentulous ridge. www.indiandentalacademy.com
  23. 23. • The stated purpose of reducing the proximal plate is to improve gingival health by opening up embrasure spaces as much as possible. www.indiandentalacademy.com
  24. 24. MODIFICATION TO RPI SYSTEM: • Kroll in 1976 has given modification to RPI system. That is • RPA in which R = rest P = proximal plate A = Akers clasp www.indiandentalacademy.com
  25. 25. contraindications for a bar- type clasp  exaggerated buccal or lingual tilts,  severe tissue undercut  or a shallow buccal vestibule  and the desirable undercut is located in the gingival third of the tooth away from the extension base area, • this modification to RPI i.e., RPA should be considered. www.indiandentalacademy.com
  26. 26. Tipped abutments and tissue impingements are • treated with RPA clasp. • When Akers clasp arm is used, careful attention is paid to relieve all undercuts except at the retentive tip www.indiandentalacademy.com
  27. 27. The removable partial denture design: british dental journal: vol-189; n0-7 pg-414 • In the study they concluded that there a plaque accumulation in terms of quality and quantity on alloplastic materials and there is some components are leached into oral cavity from this alloplastic material • And this will cause tissue injury • This can be prevented with the equillibrium in 3 components • 1- operator • 2- patient • 3- laboratory perosenell www.indiandentalacademy.com
  28. 28. 10yr old eveluation of r.p.d’s ,survival rates based in re treatment j.p.d- vol-76: no-1, 1996 • In this survey 784 patients were given with metal dentures and their feed back was taken • In the survey it was found that 88% - with 96% of success 10 people died that is 8% Remaining people didnt wear the r.p.d www.indiandentalacademy.com
  29. 29. A randomised clinical trial of 2 basic r.p.d’s- comparision of masticatory efficiency- j.p.d- 1997: 78; 15-21 • Statement of problem: there is no clinical data about the functional efficiency of different r.p.d designs. • For this 118 patients were selected with unilateral or bi lateral r.p.d’s • Conclusion: despite some performance difference at entry the mean performance scores for the 2 different groups became similar www.indiandentalacademy.com
  30. 30. conclusion • Successful use of the system requires careful analysis of each component for the function that it provides and thoughtful execution of the system in the abutment preparation and precise fitting of framework www.indiandentalacademy.com
  31. 31. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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