Record bases and Occlusal rims ppt

Record bases and oclusal rims.

1. by arbiya anjum.s Record bases & occlusion rims

2. Record bases Definition : “A record base or base plate is a temporary form representing the base of a denture. It is used in recording maxillomandibular relations and in the arrangement of the teeth ."

3. Requirements : should be rigid. should be accurate. should be stable. the borders should be round & smooth as the borders of finished dentures. should be thin at the crest ,labial & buccal slopes to provide space for tooth arrangement.

4. Objectives: -Helps in transfer of accurate jaw relation ships to an articulator - To enable the setting of artificial teeth for the trial denture.

5. Materials & methods -It is generally agreed that maxillomandibular relations are difficult -to record accurately. - Record bases are made of several different materials.

6. Types Temporary record bases: --They are discarded and replaced by denture base material, once their role in establishing jaw relation, teeth arrangement and try in is complete .

7. Types of temporary record bases: Shellac base plate Reinforced shellac base plate Cold cure acrylic resin visible light cure acrylic resin Vacuum formed vinyl and polystyrene Base

8. Permanent record bases They are not discarded and become part of the actual base of the finished complete denture. Types of permanent record bases: . Heat cure acrylic resin .Gold .Chromium-cobalt alloy .Chromium-nickel alloy

9. Shellac base plate advantages: - They will adapt to intimate contact with the master cast. -Procedure is not time consuming -cheap -uniform thickness -Can be corrected easily by reheating and readapting to the master cast.

10. Disadvantages : Quickly adapted, BUT not considered satisfactory. They warp, do not fit accurately, distort easily, lack rigidity, become brittle and break, and will not permit polishing of the borders

11. Shellac Any undercuts are relieved, and separating medium is applied to the cast. The shellac record base forms are manufactured in the shapes of the maxillary and mandibular arches.

12. The forms are softened with an open flame and molded to the cast with an instrument or the fingers. While the material is in a softened state, the excess is removed with scissors. After hardening, the borders are smoothed but as a rule will not take a polish.

13. Reinforced shellac A thin layer of zinc oxide eugenol impression paste is spread over the tissue side of the base and seated on the cast in the manner of making impression. The excess flash is removed and the borders are smoothed. Any undercuts are relieved, and separating medium is applied to the cast. The manufactured form of shellac is softened with an open flame. A flattened wire is contoured and adapted across the posterior palatal seal area of the maxillary record base and adapted to the lingual flange of the mandibular Record base and incorporated in the base .

14. Disadvantages : -Base is more rigid and stable than shellac but its still subject to distortion and breakage. - It is bulky, the odor and taste of the paste are objectionable to some patients, and it is unsuitable for arrangement of teeth in cases of limited inter arch space.

15. Cold cure acrylic resin Advantages:  Good strength no need for reinforcement  Good dimensional stability  Does not wrap during manipulation  Closely fit to the master cast

16. Disadvantages : .Require more time in fabrication .Difficult to control the thickness .Residual monomer can cause irritation to oral tissues

17. Methods . Sprinkle on method .Finger adapted dough method .Flasking method .Stone mold method * .Wax-confined method *

18. Sprinkle on method . Any undercuts are relieved, and separating medium is applied to the cast. .Using an eye dropper apply the monomer to the cast, carefully add the polymer (salt and pepper technique) until a sufficient thickness is gained over the entire surface of the cast. .The processed base is removed from the cast, smoothed, and polished at the borders .

19. Finger adapted dough method .Any undercuts are relieved, and separating medium is applied to the cast. .The self curing resin is mixed according to manufacturer instructions .When it reach the dough stage, it is molded to the cast with instrument or fingers. .It is allowed to polymerized completely. .The processed base is removed from the cast, smoothed, and polished at the borders.

20. Flasking method .A wax pattern is constructed over the cast with a thickness and contour desired for complete denture. .The cast and pattern are flasked, the wax is eliminated, acrylic resin is packed and allowed to set under the pressure of clamps or press. .The processed base is removed from the cast, smoothed, and polished at the borders.

21. Visible Light cured acrylic resin Any undercuts are relieved, and separating medium is applied to the cast. Adapt a sheet of pink base plate material to the cast by fingers and prevent trapping of air.

22. . Extend the material to the depth of vestibule. .Cure the record base for 4 minutes in the light cure unit. Carefully removed from the cast, invert and cure the tissue surface for 4 minutes. .The processed base is removed from the cast, smoothed, and polished at the borders

23. Vacuum formed vinyl and polystyrene Any undercuts are relieved, and separating medium is applied to the cast. A sheet of base plate material placed over the cast and inserted in the vaccum chamber. Electric heater switched to heat the sheet. Turn on the vacuum. The sheet will adapt closely to the cast. Switch of the heater and allow the record base to cool. Remove the record base and cut the excess material

24. Advantages .Easy to fabricate .Uniform thickness .Accurate adaptation to the .Master cast .Good rigidity Disadvantages .Expensive .Difficult to form smooth rounded .Borders .

25. Base plate wax . Wet the cast .Soften the base plate wax over the flame and adapt it to master cast .Remove the excess wax and make the borders round and smooth .

26. Advantages . Easy and rapid method .Inexpensive and available Disadvantages .It lacks rigidity .It lacks dimensional stability

27. Heat processed acrylic resin A wax pattern is constructed over the cast with a thickness and contour desired for complete denture. The cast and pattern are flasked, the wax is eliminated, acrylic resin is packed and heat processed. The processed base is removed from the cast, smoothed, and polished at the borders.

28. Advantages They are rigid, accurate, stable, not subject to distortion, and suitable for arrangement of teeth. Disadvantages : Require considerable time, more expensive.

29. Thank You

30. Occlusion Rims

31. DEFNITION “ Occluding surfaces built on temporary or permanent denture bases for the purposes of making maxillomandibular relation records and arranging teeth ”

32. REQUIREMENTS the position should be in the anticipated position of the artificial teeth. it must be securely attached to the base . the occlusal surface must be smooth and flat. it should be contoured to support the lip and cheeks accurately. all the surfaces should be smooth.

33. USES   The occlusion rims are used : To establish the level of the occlusal plane . to establish the arch form. to record the maxillary mandibular relations . for arrangement of the teeth.

34. FACTORS CONTROLLING THE FORM OF AN OCCLUSAL RIMS BA SIC FACTORS Relationship of the natural teeth to alveolar bone Relationship of the occlusal rims to the edentulous ridge Standard dimensions used to fabricate an occlusal rims. Technique of fabrication Clinical guidelines

35. RELATIONSHIP OF THE NATURAL TEETH TO ALVEOLAR BONE Occlusal rims should be fabricated such that it is parallel to the long axis of the tooth to be replaced. The maxillary anteriors are labially inclined ,hence, the occlusal rims in that area should also be labially inclined . All the posterior teeth are placed vertically ,hence, the occlusal rim should also be fabricated vertical in this region .

36. RELATIONSHIP OF THE OCCLUSAL RIMS TO THE EDENTULOUS RIDG E Residual ridge resorption changes the apex of the edendulous ridge The occlusal rim should be fabricated such that the midline of the occlusal plane pases through the apex of the EDENTULOUS RIDGE  

37. STANDARD DIMENSIONS USED TO FABRICATE AN OCCLUSAL RIMS .   ARCH ANTERIOR REGION POSTERIOR REGION HEIGHT WIDTH HEIGHT WIDTH MAXILLARY 20-22mm from the deepest part of the sulcus 3-5mm 16-18mm from the deepest part of buccal sulcus in the molar region 6-8mm MAND IBULAR 16-18mm from the deepest part of the sulcus 3-5mm At a level of the junction roof the anterior 2/3 rd & posterior 1/3 rd of the retromolar 6-8mm

38. TECHNIQUE OF FABRICATION Rolled Wax Technique. Metal Occlusal Rim Former. Pre-formed Occlusal Rim.

39. ROLLED WAX TECHNIQUE Recquirements Commonly used

40. A sheet of wax is taken and 1 end it is soften over flame & rolled to a width of 4mm .

41. Wax is then rolled carefully to avoiid air bubbles Roll is again heated and consequetive rolls are made to form a single thick cylinder of wax. Rolled wax is then adapted over the in such that it follows the arch form

42. MAXILLARY OCCLUSAL RIMS ARE USUALLY ‘U’ SHAPED & MANDIBULAR ARE ‘V’ SHAPED OR LESS WIDER ‘U’

43. The adapted wax is sealed to the base on the lingual/palatal surface using a hot wax knife

44. Mild pressure is applied on the wax to make it oval in cross section so that it overhangs a little labially.

45. The Maxillary oclusal rims shows the labial incination

46. the occlusal plane is shaped by marking height &removing excess wax using hotplate

47. the measurements are checked & posterior extent is cut with wax knife to give a slope

48. polishing By swift flaming followed by wiping it gently with a loose mass of wet cotton under running water.

49. METAL OCCLUSAL RIM FORMER Wax is rolled to a cylinder as described in previous technique The cylinder of wax is then shaped using metal occlusal rim former & stored for later use These are later adapted ,sealed & finished as described earlier

50. PRE-FORMED OCCLUSAL RIM Ready made occlusion rim its supplied as a horse shoe shaped rim, adapt it in the proper position on the record base. Softened it slightly, sealed it with the record base by the aid of a wax knife.

51. CLINICAL GUIDELINES Maxillary anterior edge should be 0-2mm below the upper lip at rest . The level of the upper lip in relation to the occlusal rims shows the lower lip line. But it varies based on age

52. M axillary posterior occlusal plane should be 1/4 th inch below the opening of the stensons duct or parotid duct Mandibular incisal edge should be at the level of lower lip & about 2mm behind the maxillary incisal edge Canine eminence of the lower occlusal rim should be located at the corner of the mouth

53. Posterior part of the mandibular rim should extent till 2/3 rd of retromolar pad

54. Anterior maxillary occlusal plane should be parallel to the inter pupillary line . the antero-posterior occlusal plane should be parallel t o the ala-tragus line or the campers line or bromel’s lin e .

55. The midline ,smile line & canine line are marked.

56. Trial in patient

57. Thank You