Neutral zone impression technique

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  • This definition is an over-simplification but serves to create a basic mental image of what a denture, constructed in the zone, is trying to achieve. It is impossible to construct a denture where the perfect, absolute equilibrium exists and no displacement occurs. The aim of the neutral zone is to construct a denture in muscle balance. That is a denture which is in harmony with its surroundings to provide optimum stability, retention and comfort.
  • FREQUENTLY COMPLAIN!!!
  • Perfect impression!
  • Ideal teeth set up
  • Balanced occlusion
  • Severely atrophic mandibular ridgePatients with high mentalis attachmentNeuromuscular disease e.g. Parkinson diseasePatients with atypical shape or consistency of oral structuresTraumaSystemic diseaseLocate optimal position for implants in cases of implant supported or retained over denturesmotor nerve damage to the tongue — which have led to either atypical movement or an unfavourable denture bearing area
  • A 52 years old female patient reported to the OPD with the chief complaint of loose mandibular complete denture. History revealed that the patient had been edentulous for the past 20 years. Patient has had two sets of complete denture made earlier and with both the dentures patient had the problem of instability of mandibular denture.Intra-oral examination revealed extremely strong mentalis and buccinator muscle which on activation led to narrowing of labial and buccal sulcus. Tongue showed uncoordinated movements. The patient had very uncertain pattern of mandibular closure. Critical examination of previous denture showed the posterior teeth were positioned lateral to the crest of the ridge. The mandibular occlusal plane was also higher further adding to instability of mandibular denture.It was therefore decided to use neutral zone impression technique to determine the optimumposition of teeth and the contour of the polished surfaces of denture in harmony with the surrounding musculature.
  • Primary impressions and secondary impressionsThe primary impressions are taken in a stock tray with a mucodisplacive material such as impression compound or a high viscosity alginate.
  • The lower secondary impression is taken in a close-fitting special tray with a low viscosity mucostatic such as a zinc oxide eugenol . The impression surface of the denture must be correctly extended to provide the maximum support from the underlying structures. The borders must be moulded to represent muscle activity, recording the functional depth and width of the sulcus
  • Neutral zone impression technique

    1. 1. SHAISTA ZAFAR
    2. 2. NEUTRAL ZONE
    3. 3. Gahan and Walmsley (2005) defined neutral zone as the area in the mouth where during function, the forces of the tongue pressing outwards are neutralised by the forces of the cheeks and lips pressing inwards.
    4. 4. Free template from www.brainybetty.com 5
    5. 5. NEUTRAL ZONE IMPRESSION TECHNIQUE
    6. 6.  It’s a physiological and functional approach that is widely and concisely described as a treatment modality for unstable lower complete denture cases Free template from www.brainybetty.com 7
    7. 7.  who have had numerous unstable, unretentive lower complete dentures.
    8. 8. EVEN AFTER HAVING..
    9. 9.  Atrophies mandible>maxilla  Mandible has less residual ridge for retention and support  Difficulty for positioning the teeth to produce a stable denture
    10. 10. Free template from www.brainybetty.com 17
    11. 11. Free template from www.brainybetty.com 19 LABIAL RESORPTION
    12. 12. Free template from www.brainybetty.com 20
    13. 13. FORCES INWARD FORCES OUTWARD FORCES Buccinator Modiolus Orbicularis oris TONGUE
    14. 14. Free template from www.brainybetty.com 22
    15. 15. INDICATIONS CATIONSIONS
    16. 16.  Severely atrophic mandibular ridge  High mentalis attachment  Neuromuscular disease  Atypical shape of oral structures  Trauma  Systemic disease  Locate optimal position for implants.  Partial glossectomy  Motor nerve damage to the tongue 25
    17. 17. AIM
    18. 18.  Is to improve denture stability by constructing a denture that is shaped by muscle functionand is in harmony with the surrounding oral structures.
    19. 19. OTHER ADVANTAGES
    20. 20.  Improved stability and retention  Posterior teeth will be correctly positioned allowing sufficient tongue space  Reduced food trapping adjacent to the molar teeth  Good aesthetics due to facial support.
    21. 21. MATERIAL USED FOR NEUTRAL ZONE IMPRESSION
    22. 22.  Stock trays  Impression Compound  Zinc Oxide Eugenol  Custom tray  Green stick  Orthodontic Ni/Ti wires  ModelingWax  Tissue ConditionersFree template from www.brainybetty.com 31
    23. 23. Free template from www.brainybetty.com 32 CASE REPORT
    24. 24. Free template from www.brainybetty.com 33 EDENTULOUS MAX ARCH EDENTULOUS MANDIBULAR ARCH
    25. 25. Free template from www.brainybetty.com 34 CLINICALTECHNIQUE
    26. 26. Free template from www.brainybetty.com 35 :Preliminary impression with impression compoundSTEP 1
    27. 27. Free template from www.brainybetty.com 36 STEP 2 Wash impression with Zinc Oxide Eugenol
    28. 28. Free template from www.brainybetty.com 37 A lower acrylic special tray with metal spurs to aid retention of the impression material STEP 3
    29. 29. Free template from www.brainybetty.com 38 JAW RELATIONSTEP 4:
    30. 30. Free template from www.brainybetty.com 39 STEP 5STEP 5: Occlusal pillars built in green stick to establish the occlusal height
    31. 31. Free template from www.brainybetty.com 40 STEP 6 Tissue conditioner being molded with the mouth movements
    32. 32. Free template from www.brainybetty.com 41 STEP 7: The tray now kept on the cast
    33. 33. Free template from www.brainybetty.com 42 STEP 8: Plaster index formed around the neutral zone impression  Neutral zone impression removed to make the wax rim
    34. 34. Free template from www.brainybetty.com 43 STEP 9: Wax rim formed
    35. 35. Free template from www.brainybetty.com 44 STEP 10: Teeth set up in neutral zone
    36. 36. Free template from www.brainybetty.com 45STEP 11: INSERTION
    37. 37.  Special impression techniques are useful for the construction of lower complete dentures on highly atrophic ridges in cases where dental implants are not possible  Neutral zone impression technique is a useful technique aims to construct a denture in muscle balance, it is relatively simple but it is demanding both clinically and technically.
    38. 38.  Prosthodontic treatment for edentulous patients- 13th edition by ZARB,HOBKIRK,ECKERT,JACOB  Clinical dental prosthetics-FENN & GIMSON’S  GAHAN, M. J. &WALMSLEY, A. D. 2005.The neutral zone impression revisited. British dental journal, 198, 269-272  http://www.slideshare.net/eugeneyeoh1/piezograp h-2  http://www.jaypeejournals.com/eJournals/ShowTex t.aspx?ID=3376&Type=FREE&TYP=TOP&IN=_eJour nals/images/JPLOGO.gif&IID=261&isPDF=NO  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC308 1261/
    39. 39.  F  L O B R U S H I S N T S M I L E E E T H A N KY O U H

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