theneutralzoneincompletedentures-230122173853-5c7d6016.pptx

Neutral zone in complete denture

1. The Neutral zone in complete dentures JOURNAL CLUB

2. TITLE - The Neutral zone in complete dentures GENRE -CLASSIC ARTICLE SOURCE Beresin VE, Schiesser FJ. The neutral zone in complete dentures. The Journal of prosthetic dentistry. 1976 Oct 1;36(4):356-67. AUTHORS Victor E. Beresin, Frank J. Schiesser Temple University School of Dentistry, Philadelphia

3. INTRODUCTION

4. 1) The potential space between the lips and cheeks on one side and the tongue on the other; that area or position where the forces between the tongue and cheeks or lips are equal (GPT9) 2) The neutral zone has been defined as the area in the mouth where during function,the forces of the tongue pressing outwards are neutralised by the forces of cheeks and lips pressing inwards – Beresin & Schiesser

5. Muscle force in the dental arch muscular activity and habits which develop during childhood continue through life. It is therefore, extremely important that the teeth be placed in the mouth with the arch form located so that it will fall within the area compatible with muscular forces.

6. Denture surfaces surfaces Occlusal surface Occlusal surface Impression surface Impression surface Polished surface SIR WILFORD FISH external or polished surface of the denture is in contact with the cheeks, lips, and tongue

7. Influence of forces on denture surfaces RIDGE LOSS DENTURE BASE AREA Impression surface Polished surface

8. (From Beresin VE, Schiesser FJ. The neutral zone in complete dentures. St. Louis: C. V. Mosby Co; 1973.

9. (From Beresin VE, Schiesser FJ. The neutral zone in complete dentures. St. Louis: C. V. Mosby Co; 1973.

10. (From Beresin VE, Schiesser FJ. The neutral zone in complete dentures. St. Louis: C. V. Mosby Co; 1973.

11. (From Beresin VE, Schiesser FJ. The neutral zone in complete dentures. St. Louis: C. V. Mosby Co; 1973.

12. Reversed Sequence in Denture Construction Primary impression Trays Final impression Record base and rims Jaw relation Try in Denture deliver Trays Occlusal rims (impression compound) Final impression ( close mouth) Normal CD Neutral zone CD

13. Base and Body of denture Impression surface Polished surface base Body By separating these two entities, the dentist can more readily determine and correct the cause of instability of the denture.

14. External Impression the neutral-zone procedure, the external contours are molded by muscle function By means of these external impressions, a physiologic molding is done so that the external surfaces are functionally compatible with muscle action External impressions, similar to secondary impressions of the ridge, capture in greater detail the action of the lips, cheeks, and tongue and determine the thickness, contours, and shape of the polished surface of the denture

15. (A) Labiobuccal impression on lower trial denture. Note the narrowing in the bicuspid area created by muscle function. (B) and (C) External lingual lower impression. Note the ledge formed by the tongue during swallowing. (From Beresin VE, Schiesser FJ. The neutral zone in complete dentures. St. Louis: C. V. Mosby Co; 1973.)

16. Understandable schematic dig Denture construction is not well explained muscles which are involve are not explained FINDINGS

17. RELATED ARTICLES Gahan MJ, Walmsley AD. The neutral zone impression revisited. British dental journal. 2005 Mar;198(5):269-72. The neutral zone impression revisited

18. A denture shaped by the neutral zone (NZ) technique will ensure that the muscular forces are working more effectively and in harmony. The dentures will have other advantages: • Improved stability and retention • Posterior teeth will be correctly positioned allowing sufficient tongue space • Good aesthetics due to facial support.

19. BUCCINATOR TONGUE MODIOLUS ORBICULARIS ORIS, MENTALIS MAJOR MUSCLES

20. The role of the buccinator during function is to position food on the occlusal surfaces of the teeth. This action is coordinated with the tongue to maintain the food in this position. BUCCINATOR In the highly atrophic, mandible positioning of the anterior teeth can be problematic. The NZ technique provides the correct tooth position to allow for the balancing of these muscular forces during function. ORBICULARIS ORIS, MENTALIS TONGUE The tongue is a powerful group of muscles and it is in constant contact with the denture at rest and during function.

21. The modiolus determines the position of the premolar teeth and the shape of the polished surface in that region. This produces a narrowing of the denture so that the polished surface does not hinder the movements of the modiolus during function

22. The aim of the neutral zone is to construct a denture in muscle balance, as muscular control will be the main stabilizing and retentive factor during function. The technique is relatively simple but there are increased chair time and laboratory costs CONCLUSION

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