Remounting of complete dentures

Step in complete denture fabrication
Laboratory and clinical remounting of complete dentures.

1. Remounting Presented by: Dr. Rajvi Nahar 1 st year post graduate

2. Contents Introduction Definitions Need for remounting Direct correction in mouth Laboratory remounting Clinical remounting Selective grinding Remounting with different articulators Adjustment in complete and partial dentures Conclusion References

3. Introduction Complete dentures are prosthetic replacements for lost natural teeth and lost soft and bony tissues, which are fabricated in order to restore impaired functions and appearance. The comfort of a prosthesis is a commonly recognized prerequisite for positive adjustment to a newly fabricated complete denture. Occlusal discrepancy is reported to be one of many factors that may cause tissue irritation.

4. This discrepancy may lead to an unstable denture, applying uneven pressure to both hard and soft tissues. Occlusal discrepancy can result from warping of the record bases, incorrect centric relationship recording, or other faulty procedures in mounting and processing. The efficiency and comfort that a patient experiences using complete dentures depends to a large extent on the harmony of the occlusion.

5. Definitions (According to GPT 9) Remount cast: A cast formed inside the intaligo of a prosthesis for the purpose of mounting the prosthesis on an articulator. Remount procedure: Any method used to relate restorations to an articulator for analysis and/or to assist in development of a plan for occlusal equilibration or reshaping. Remount record index: A record of maxillary structures affixed to the mandibular member of an articulator useful in facilitating subsequent transfers.

6. Causes of error in occlusion Errors in registering jaw relation: 1. Record bases that do not fit accurately. 2. A shifting of the record bases over displaceable tissues. 3. Record bases placed on soft tissues that have been deformed by ill-fitting dentures.

7. 4. Excessive pressure exerted by the patient during jaw relation. 5. Unequal distribution of stress during registering maxillo-mandibular relations. 6. Patients not registering centric relations due to systemic factors- muscle spasm, abnormalities of TMJ, or mental failure, age, senile patients.

8. Errors in mounting casts: Record bases that are not properly seated and secured to casts during mounting procedures. Occlusal rims not being definitely locked for correct orientation during mounting on articulators. Interference of casts in posterior region during mounting. Articulator not maintaining horizontal and vertical jaw relationship of casts. Inaccuracies introduced by changes in the plaster used to mount the cast.

9. Errors while flasking and packing 1. Tooth movement while de-waxing. 2. Excessive packing pressures results in the artificial teeth being forced into the investing plaster. 3. If the acrylic resin has reached an advanced dough stage.

10. 4. Normal packing pressures when the investing mix is weak can break the mould . 5. Tooth movement while flasking and packing. 6. Incomplete Flask closure. 7. If pressure on the flask is released during the curing cycle. 8. Separation of the two halves of the flask by a layer of excess resin which should have been removed during trial closure of the flask(flash ).

11. Indexing the master cast Groove indexing method Notch indexing method

12. Methods to correct Occlusal Discrepancies

13. Direct correction in mouth Articulating Paper: It will not give an accurate indication of premature contacts – Resiliency of supporting tissues Tipping of denture bases If placed on one side of the arch, induce the patient to close to or away from that side. Place articulating paper on both sides.

14. Central Bearing Devices: THE CORRELATOR: A central bearing pin works on spring. Pin in mandibular mounting c ontacts metal plate in the vault of maxillary denture . Pin creates tension before the teeth contacts. Interceptive occlusal contacts with articulating ribbon. THE COBBLE DEVICE: A central bearing pin without spring.

15. Occlusal wax: Adhesive green wax: Excellent method for correcting occlusion in centric position only. Disadvantage – shifting of dentures on resilient supporting tissues in eccentric jaw position will give false markings. Abrasive paste: Disadvantages: shifting of base as a result of premature contact may result in altering the occlusion. Cusps that maintain occlusal vertical dimension may be destroyed.

16. Laboratory Remount Procedure A laboratory remount procedure removes the processing errors that occur prior to removal of dentures from the definitive cast. A remount procedure begins with fabrication of remount casts, determination and transfer of interarch relationships into the articulator. Deflective contacts on dentures are eliminated by selective grinding carried out in the articulator in the intercuspal position and by excursive tooth guided movements.

17. Preparation of dentures for fabrication of remount casts Check relationship of the incisal guide pin to the incisal guide table

18. Check contacts between heel of mandibular dentures and tuberosity region of maxillary denture Place articulating paper to check deflective contacts

19. Adjust occlusion in centric relation position and in eccentric relation, according the rules of selective grinding. Move the articulator into working position and examine the occlusal relationship.

20. Eliminate deflecting contacts Examine balancing contacts Check occlusion by moving articulator in various position Incisal guide pin should contact the incisal guide table Recheck the occlusion

21. Making a face-bow index Remove mandibular denture and cast from mounting and scrape off any sticky wax. Box the lower mounting stone with boxing wax Extend upper edge of boxing wax 1-2mm above the level of occlusal surface of maxillary teeth. Seal the boxing wax to the stone to make it watertight. Pour water into the boxed stone to soak it and facilitate joining of the next pour of the stone.

22. Paint the occlusal surfaces of the maxillary teeth with the microfilm of separating medium. Mix the stone and fill the boxed area. Place additional stone on occlusal surfaces of maxillary teeth. Allow the stone to set; then remove the boxing wax and trim it. The face-bow index is complete.

23. Split Cast Mounting Technique The ‘‘split cast ’’ ( Given by J.W. Needles in 1923) is essentially a maxillary cast constructed in two parts with a horizontal division . The first part of the split maxillary master cast with index grooves, is known as primary base. The design, number, and position of the index grooves are determined on the basis of the height of the palatal vault, depth of the sulcus and the personal preference of the clinician. Gundawar SM, Pande NA, Jaiswal P, Radke UM. Split Cast Mounting: Review and New Technique. The Journal of Indian Prosthodontic Society. 2014 Dec 1;14(1):345-7.

24. The second part, which is fitted to the master cast and is attached to the upper member of the articulator is referred to as secondary base or sandwich. The perfect fit of the master cast, sandwich and upper member of the articulator verifies the correct centric relation record. If gap is present between the master cast and sandwich or sandwich and upper member of the articulator that determines the previous recording of centric relation is incorrect.

25. Nogueira , S. S., Russi , S., Compagnoni , M. A., & de Assis Mollo , F. (2004). A variation on split-cast mounting for complete denture construction. The Journal of Prosthetic Dentistry, 91(4), 386–388. doi:10.1016/j.prosdent.2004.02.002 

26. The sandwich should have a contrasting color for easy detection and should also have index grooves. The split cast mounting procedure allows for: Ease of removal and replacement of the casts. To program the articulator by means of eccentric records. Verification of centric jaw relation records. For correcting occlusal errors as a result of the processing technique.

27. After the final impression, beading and boxing is completed. Two dowel pins with plastic/metal sleeves, are then inserted in the boxing wax, with a gap of 2–3 mm on right and left side. Remove the dowel pins from their sleeves and after fi nishing of the cast, the dowel pins are reinserted in their sleeves. Base of master cast is sharply grooved. Secondary base is poured.

28. Using face bow, the combined primary and secondary base cast are mounted on the upper member of the articulator. Two metal plates with serrations on one end (routinely available forks) are cut in required length. The other end is also slightly notched, for encircling the ligature wire. During mounting, before plaster sets hard, these plates with serrated end, are inserted into plaster on right and left side.

29. Once the plaster sets hard, the ligature wire is moved around the two dowel pins which is attached to the master cast. It is encircled over the notched surface of the metal plate, tightened to stabilize the upper mounting. Advantage: Damage to cast is minimum. Mounting is stable. Easy to use. Easy removal and reattachment of maxillary cast to the articulator. Disadvantage: Extra time is required in attaching the dowel pins to the cast .

30. Modified Split Cast technique BEFORE APPOINTMENT: Fabricate maxillary and mandibular remount casts. Mount the maxillary remount cast and maxillary denture with the preserved face bow record in the upper jaw member of the semi-adjustable articulator Liu FC, Luk KC, Suen PC, Tsai TS, Ku YC. Modified Split‐Cast Technique: A New, Timesaving Clinical Remount Technique. Journal of Prosthodontics : Implant, Esthetic and Reconstructive Dentistry. 2010 Aug;19(6):502-6.

31. Fabricate mandibular secondary remount base. The incisal pin is set at −3 and locked. The articulator is inverted for convenience in mounting. Using maximal intercuspation of the maxillary and mandibular dentures, secure the mandibular denture along with its remount cast. Apply plaster separator (tin foil, tin foil substitute, or lubricating jelly) to the bottom of the mandibular remount cast.

32. Mount the mandibular cast, along with its denture, on the lower jaw member of the articulator with dental plaster, forming a secondary remount base. Separate the mandibular remount cast from the secondary remount base, reset the incisal pin, and lock at zero. Thus, a space approximately 1- to 2-mm thick is created between the mandibular remount cast and the secondary remount base. Remove maxillary and mandibular dentures from the corresponding remount casts.

33. Attach maxillary remount cast and mandibular secondary remount base cast to the upper and lower jaw members of the articulator, making ready for the clinical remount procedure.

34. Clinical remount procedure Cover the tissue side of each denture with pressure indicating paste or disclosing agent and make appropriate corrections intraorally. Make a centric relation interocclusal record with an addition-type, silicone bite-registration material.

35. Secure the maxillary and mandibular dentures on their respective remount casts. Relate the mandibular cast to the maxillary cast according to the interocclusal record and lute them together with wooden rods and sticky wax.

36. Adjust incisal pin height and inject the Futar D into the space created between the mandibular remount cast and the secondary mounting base, close the lower jaw member of articulator, and wait for Futar D to set. Because Futar D is fast setting (2-minute setting time) and has low elastic properties , it can be used as a remounting medium. Check the interocclusal relationship on the articulator, if necessary.

37. Separate mandibular remount cast, then repeat steps 4 and 5 until a repeatable and stable centric relation position is obtained. After the accuracy of the articulator mountings is verified , occlusal errors can be corrected by selective grinding procedures.

38. This clinical remount technique utilizes maxillary and mandibular Customized Mounting Plates (CMPs) that are fabricated over mounting plates of articulator. 1. Enfold boxing wax around the outside edge of the maxillary and mandibular mounting plates to form diverging housing for holding the dental plaster. A simplified chair-side remount technique using customized mounting platforms

39. Customized mounting platforms (CMP) has these advantages: ( 1) remount casts are not fabricated separately for remounting complete dentures; (2) the mandibular denture can be remounted quickly with a new centric relation record, in case of incorrect centric relation record; (3) blocking out undercuts from the tissue surface of denture is not necessary; (4) mounting can be performed at chair-side with minimal mess and; (5) the putty impression material can be conserved as a record to be used in successive appointments if needed. Chauhan MD, Dange SP, Khalikar AN, Vaidya SP. A simplified chair-side remount technique using customized mounting platforms. The journal of advanced prosthodontics . 2012 Aug 1;4(3):170-3.

40. 2. Reduce the boxing wax for the maxillary and mandibular mounting plates such that the diameter at the opening is 6.5 cm. 3. Similarly, trim the height of maxillary boxing wax at 2.5 cm and that of mandibular boxing wax at 2 cm. 4. Pour a mix of dental plaster to fill both the divergent cylinders. 5. Allow the dental plaster to set and remove the boxing wax.

41. 6. Carve a horse-shoe shaped groove on the flat surfaces of both the divergent cylinders . 7. Form a mix of self cure acrylic resin into two spools and place over the grooves of both the maxillary and mandibular divergent cylinders to form U-shaped positive replica of edentulous ridges. Adjust the vertical height of the ridges to 5 to 6 mm.

42. 8. Trim these acrylic edentulous ridges with fissure bur to make buccal and lingual undercuts that will provide port for the putty impression material during subsequent mounting of the dentures. 9. Finish and polish both the customized mounting platforms.

43. Chair-side remounting of the dentures 1. Check the intaglio surface of each denture in the mouth with pressure-indicating pastes or waxes and make the needed adjustments. 2. Make a centric relation inter-occlusal record with a soft medium such as warm Aluwax to confirm closure without contact of the denture teeth or bases. 3. Attach the maxillary and mandibular CMPs in the articulator.

44. 4. Place the putty impression material in the form of a U-shaped roll over the mandibular acrylic resin edentulous ridge on the CMP and position the mandibular denture on it. 5. Secure the maxillary denture over mandibular denture with the help of the centric interocclusal record in aluwax , place the putty material in the denture in the region of alveolar ridge, and close the upper member of the articulator into the putty material.

45. 6. After the putty impression material has set, open the articulator and remove the interocclusal record. 7. The putty material serves as remount casts . 8. Close the denture onto articulating paper and adjust the occlusion.

46. Patient Remount Procedures The patient remount method is to remount the dentures on an articulator by means of interocclusal records made in the patient’s mouth. Advantages: Reduces patient participation. Permits dentist to see the procedures better. Provides stable working foundation. Absence of saliva makes possible accurate markings with the articulating paper or tape. Corrections can be made away from patients.

47. Procedure Place two thickness (1½ mm) of passive–type wax on the occlusal surfaces. Soften wax with alcohol torch or immerse in water at 130°F . Have the patient close into the wax when the jaws are in centric relation. Trim the wax and expose the facial side.

48. Seat the mandibular cast in the denture and attach to mandibular member of the articulator with plaster. Orient mandibular denture to the maxillary denture by means of interocclusal record with jaws in centric relation with sticky wax. With the condylar elements freed, place teeth in the indentations in the wax interocclusal record. Condylar elements should rest against stops. Repeat procedure until two consecutive records are accepted. Verify the accuracy of articular mountings.

49. Definition: The intentional alteration of the occlusal surfaces of the teeth to change their form. Articulating paper of minimum thickness is used for marking the actual contacts of the teeth.(less than 21 µm thick)* The diagnostic adjustment was first made on the casts and then on the patient using four differently colored ribbons :** 1. Red: centric stops 2. Black: protrusive interferences 3. Green: working side interferences 4. Blue: balancing side interferences Selective Grinding Procedures ** Raheja R, Mahajan T, Singh R, Singh N. SELECTIVE GRINDING/OCCLUSAL RESHAPING IN PROSTHODONTICS. *Malta Barbosa , J., Urtula , A. B., Hirata, R., & Caramês , J. (2017). Thickness evaluation of articulating papers and foils. Journal of Esthetic and Restorative Dentistry, 30(1), 70–72. doi:10.1111/jerd.12343 

50. In the first step, cusp form teeth are altered by selective grinding to obtain balanced occlusion when the jaws are in centric relation . Occlusal balance in a lateral direction is obtained by having all of the posterior teeth and the cuspids in contact on the working side and in posterior contact only on the balancing side . In the protrusive balance the anterior teeth should make incisal edge contact at the same time that the tips of the buccal and lingual cusps of the posterior teeth contact . Adjust horizontal and lateral condylar inclinations of the articulator to the settings dictated by the protrusive interocclusal maxillomandibular relation record.

51. Raise incisal guide pin from the guide table and secure it above the height of the table . Evaluate areas of contact in the centric and eccentric positions prior to the selection of the point or area to be reduced or altered . With the condylar elements against the centric relation stops , close the articulator until the posterior teeth are in contact . the anterior teeth should not be in contact . Examine the lingual cusps of the maxillary posterior teeth and the buccal cusps of the mandibular posterior teeth . Premature contact appears when the remainder of the teeth fail to make maximum intercuspation. Record the area or areas of premature contact .

52. Grinding in Centric : 1. The first objective is to remove premature contacts in centric occlusion. 2. Mark the interfering cusps with articulating paper.

53. 3. In the retruded contact position there are three types of occlusal errors and each can be corrected by specific grinding : Any pair of antagonist teeth can be too long and thus hold other teeth out of contact. 1.If the offending cusp makes premature contact in centric as well as eccentric ground the cusp. 2.If the offending cusp makes premature contact in centric only, deepen the opposing fossa .

54. The lower and upper teeth can be placed almost edge- to-edge: Grinding cuspal inclines- palatal inclines of maxilla and buccal inclines of mandible. Cusps are not shortened.

55. Too much horizontal overlap : Maxillary palatal and mandibular buccal cusps are made narrow, not short.

56. Grinding in Eccentric : 1.The maxillary buccal cusp and the mandibular lingual cusp are too long : The inner inclines of BUCCAL cusps of UPPER and LINGUAL cusps of LOWER (BULL) are adjusted.

57. 2. The buccal cusps are in contact, but the lingual are not : The lingual inclines of upper buccal cusps are ground.

58. 3. The lingual cusps are in contact, whereas the buccal are not ▫ Buccal inclines of mandibular lingual cusps are reduced in order to shorten the cusp.

59. 4.The maxillary buccal or palatal cusps are positioned more mesially from their intercuspal position(MU-DL): Grinding should be done on the mesial inclines of the maxillary buccal cusps and distal inclines of the mandibular buccal cusps.

60. 5.The maxillary buccal or lingual cusps are positioned more distally from their intercuspal position : Grinding should be done on distal inclines of maxillary buccal cusps and mesial inclines of mandibular buccal cusps .

61. 6. No contact on working side due to excessive contact on the balancing side: buccal cusps of the mandibular teeth (balancing side) are altered on their inclines.

62. Occlusal Errors on the Non-working side : Mandibular buccal cusp are adjusted to reduce the incline of the part of the cusp that prevents tooth contacts on the working side.

63. Eliminating Occlusal Errors in Non- Anatomic Teeth: Maxillary posterior are flattened by sanding on ultrafine sand paper against a truly flat surface . After placing on the remount casts and articulation , occlusal contacts are marked . Selective grinding is done only on the mandibular teeth

64. Occlusal Adjustment in Average Value Articulator: Remounting of the dentures requires an average value or semi-adjustable articulator be used to examine the lateral and protrusive occlusal contacts. Using a simple hinge articulator is not satisfactory, as lateral excursions are not possible. The retruded contact position is recorded intraoral using soft wax.

65. The upper denture is articulated so that the center pin, touches the mid-line at the upper incisal edge. The lower denture is attached to the articulator ensuring that the occlusal plane is horizontal and parallel to the base of the articulator . When the plaster has set, the wax is removed between the occlusal surfaces of the teeth and the occlusal adjustment is carried out. When the wax is removed, the teeth than contact, rotating around condylar axis of the articulator.

66. Full Dentures Opposed to Partial Dentures : Maxillary complete dentures and mandibular partial dentures: 1 . Similar procedures as previously mentioned are carried out . 2 . Avoid grinding natural teeth.

67. Partial Upper denture and Lower complete Dentures: For maxillary and mandibular distal extensions with only anterior teeth remaining previously described procedures can be carried out. For small partial dentures, the opposing natural dentition is adjusted .

68. Conclusion Correct occlusal relationships are a part of the success in prosthetic treatment for edentulous patients with complete dentures. A clinical remount procedure of the finished dentures is a constituent part of prosthetic patient treatment in practice of complete dentures. The laboratory and clinical remount procedures, along with occlusal corrections, reduces the number of areas of tissue irritation, post insertion visits, pain during mastication and swallowing, and discomfort during mastication, and enhanced the comfort of the patient .

69. The clinical remount also maintains the stability of dentures when the mandible is in centric relation position Selective grinding helps to remove the occlusal errors in a systematic way . Occlusion of such dentures is more stable for longer time and with less parafunctional movements. Hence, a more satisfied patient.

70. References Syllabus of complete Dentures ; Heartwell 4th edition Prosthodontic Treatment for Edentulous Patients ; Zarb , Hobkirk et al 13th edition Dental Laboratory Procedures volume 1 ;Rudd and Morrow Nallaswamy D. Textbook of prosthodontics . JP Medical Ltd; 2017 Sep 30. Gundawar SM, Pande NA, Jaiswal P, Radke UM. Split Cast Mounting: Review and New Technique. The Journal of Indian Prosthodontic Society. 2014 Dec 1;14(1):345-7. Liu FC, Luk KC, Suen PC, Tsai TS, Ku YC. Modified Split‐Cast Technique: A New, Timesaving Clinical Remount Technique. Journal of Prosthodontics : Implant, Esthetic and Reconstructive Dentistry. 2010 Aug;19(6):502-6. Chauhan MD, Dange SP, Khalikar AN, Vaidya SP. A simplified chair-side remount technique using customized mounting platforms. The journal of advanced prosthodontics . 2012 Aug 1;4(3):170-3 . Nogueira , S. S., Russi , S., Compagnoni , M. A., & de Assis Mollo , F. (2004). A variation on split-cast mounting for complete denture construction. The Journal of Prosthetic Dentistry, 91(4), 386–388. doi:10.1016/j.prosdent.2004.02.002  Raheja R, Mahajan T, Singh R, Singh N. SELECTIVE GRINDING/OCCLUSAL RESHAPING IN PROSTHODONTICS Malta Barbosa , J., Urtula , A. B., Hirata, R., & Caramês , J. (2017). Thickness evaluation of articulating papers and foils. Journal of Esthetic and Restorative Dentistry, 30(1), 70–72. doi:10.1111/jerd.12343  .

71. Thank you