4. 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.
7. 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
8.
9.
10.
11. who have had numerous
unstable, unretentive lower
complete dentures.
16. Atrophies
mandible>maxilla
Mandible has less
residual ridge for
retention and support
Difficulty for positioning
the teeth to produce a
stable denture
27. Is to improve denture stability
by constructing a denture that is shaped
by muscle functionand is in
harmony with the
surrounding oral
structures.
29. 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.
39. Free template from www.brainybetty.com 39
STEP 5STEP 5: Occlusal pillars built in
green stick to establish the
occlusal height
40. Free template from www.brainybetty.com 40
STEP 6
Tissue conditioner being molded with
the mouth movements
41. Free template from www.brainybetty.com 41
STEP 7: The tray now kept on the cast
42. 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
46. 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.
47. 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/
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Editor's Notes
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
