C&b+pk thomas+technique+ver2
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P.K.Thomas Waxing Technique a ‘drop wax’ or ‘wax added’ technique Construct Crown & Bridge Structures 510B Ver2 1
Transcript of C&b+pk thomas+technique+ver2
P.K.Thomas Waxing Technique
a ‘drop wax’ or ‘wax added’ technique
Construct Crown & Bridge Structures 510B Ver2 1
Why put all those grooves on the occlusal surface??
Why not put simple inclined planes on a flat table??
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IntroductionThere are many positive and negatives features on a tooth eg, cusp tips and ridges.
The ridges, when properly formed, are convex in all directions. Buccolingually and mesiodistally. This is to provide point contacts with the opposing cusps.
The convex surfaces of ridges produce a distributedcontact pattern with small contacts. In this way occlusal forces are distributed over a wide area of the occlusal surface.
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The grooves perform an important function.
If they are adequate in width and depth and traverse the occlusal surface in the proper direction, they will permit the smooth unimpeded passage of the opposing cusps in excursive movements.
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A ‘wax adding’ exercise
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The ‘cusp cone’ and marginal ridges
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Supplementary or axial ridges
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Filling in axial contours
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Making triangular ridges
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Cusp cones on Mandibular 2nd Premolar and 1st molar
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Occlusal contacts on mesial marginal ridges
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Occlusal contacts on distal marginal ridges
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Occlusal contacts on buccal Triangular ridges
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Tripodisation or
3 point contactOcclusal contacts on lingual triangular ridges
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Inter-occlusal contacts
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The functional cusps (lingual of the maxillary and buccal of the mandibular) are the cusps to locate first. They should be positioned so they will contact the appropriate fossa or marginal ridge of the opposing tooth.
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The maxillary buccal nonfunctional cuspsneed to be short enough to miss contacting the mandibular buccal ‘functional’ cusps during excursions.
The mandibular lingual nonfunctional cuspsneed to be slightly shorter than the buccal and placed as far to the lingual.
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