SPACER DESIGNS AND STOPPERS................

SPACER DESIGNS AND STOPPERS; DIFFERENT AUTHORS; DIFFERENT DESIGNS; CASE REPORTS ; DIFFERENT TECHNIQUES;CONCLUSION

1. Designs of spacers and s toppers Prepared by : Dr Viswalekshmi R M 2 nd year PG Dept of Prosthodontics & Crown and Bridge 1

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3. Introduction A n impression is an ART and the first step in the fabrication of a complete denture prosthesis. Many techniques are advocated for making impressions by various authors. Out of which the most acceptable is Boucher’s Selective Pressure Therory . I mpression making is a sophisticated procedure comprising of different learning curves. Yogeshwari , Aeran H Different spacer designs in complete denture prosthodontics; Guident 2021 3

4. “Ideal impression must be in the mind of the dentist before it is in his hand. He must literally Make the impression rather than Take it’’ M M Devan 4

5. History 5

6. 1.Based on amount of pressure, there are four basic impression theories that have been proposed and accepted over the years : Mucostatic , Mucocompressive Minimal pressure Selective Pressure Techniques. Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 6

7. Mucostatic impression Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 7 Passive impression / non-pressure impression Proposed by Richardson and popularised by Henry Page based on the Pascal's law It is made with oral mucous membrane and jaws in normal relaxed position . Border moulding is not done. Impression is made with oversized trays with impression plaster. Good denture stability Disadvantages ;- poor retention, retention only because of interfacial surface tension lack of peripheral seal.

8. Mucocompressive impression Definitive pressure impression Made with waxes, impression compound etc . Tissue is displaced Dentures made with this technique rebound back at rest. But at function constant pressure is applied can decrease circulation and may lead to ridge resorption . Use of high viscosity impression materials, impression compounds, irreversible hydrocolloids, putty & heavy body elastomeric impression materials is done. Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 8

9. Minimal pressure  technique   It is a compromise between Mucocompressive and Mucostatic Impression Technique. In this technique minimal pressure is applied, which is a little more than that of a free flowing material. The disadvantage is that there is a lack of standardized protocol regarding the pressure to be applied during the impression. Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 9

10. Selective pressure technique Proposed by Boucher .,1950 Combines both mucocompressive and minimal pressure techniques Impression extended as much denture bearing area as possible Forces only on stress bearing area. Made by using special tray . With use of spacer designs Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 10

11. Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 11 Selective Pressure may be achieved by scrapping the primary cast/impression in the selective areas or by the fabrication of a custom/special tray with proper spacer design with different materials & designs and adequate extensions, tissue stops, escape holes for relief. Latter is better However views of different authors on how to achieve selective-pressure impression are different

12. The classification of spacer designs 1. FULL SPACERS: it is made to cover the whole residual ridge 2. PARTIAL SPACERS: based on clinical needs. It is made to cover specific areas only 3. SPACERS WITH TISSUE STOPPERS: tissue stoppers/ windows are made bilaterally Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 12

13. Spacer Thickness Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 13

14. Spacer Materials Used Over the Years Tin foil Casting wax Non asbestos ring liner Base-plate. Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 14

15. Spacer Design by Different Authors Boucher Based on selective-pressure technique Advocated the placement of 1 mm base-plate wax on the entire basal seat area Except posterior palatal seal ( PPS) area. He also advocated the placement of e scape holes in the palatal region 1 mm thick base-plate wax covers mandibular ridge except buccal shelf area and retromolar pad Dr Aruna J, Bhandari I etal Spacer designs for impression techniques in conventional complete dentures;VIMS health science jrnl;vol:4;no.1 march 2017 15

16. Morrow, Rudd, and Rhoads Based on minimal-pressure technique, Recommend blocking out undercut areas with wax Adapting a full wax spacer 2 mm short of the resin special tray border all over. Placement of three tissue stops equidistantly Dr Aruna J, Bhandari I etal Spacer designs for impression techniques in conventional complete dentures;VIMS health science jrnl;vol:4;no.1 march 2017 16

17. Sharry Based on minimal-pressure technique, Recommends adaptation of a layer of base-plate wax over the whole area outlined He recommends the placement of four tissue stops and one vent hole in the incisive papilla region before making the final impression with the metallic oxide impression material Dr Aruna J, Bhandari I etal Spacer designs for impression techniques in conventional complete dentures;VIMS health science jrnl;vol:4;no.1 march 2017 17

18. Bernard Based on selective pressure technique Recommends a layer of pink base-plate wax (about 2 mm thick) attached to the areas of the cast that usually have the areas of softer tissues He recommends the placement of wax spacer all around, except the posterior part of the palate, Dr Aruna J, Bhandari I etal Spacer designs for impression techniques in conventional complete dentures;VIMS health science jrnl;vol:4;no.1 march 2017 18

19. Halperin : Peripheral relief by providing 1 mm thick wax relief over the peripheral extensions and buccal slope region of tray including PPS and that the custom tray be in intimate contact with basal seat areas This makes the internal finish line to butt joint. No secondary wash impression is needed. Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307. 19

20. Roy Mac Gregor : Rcommends placement of a sheet of metal foil in the region of incisive papilla and midpalatine raphe. It is based on the selective pressure technique . He says that the other areas which must be relieved are the maxillary rugae , other areas which are subject to mucosal damage, buccal surface and the prominent tuberosities . But he says that relief need not be given routinely in the dentures 20 Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307.

21. Neil recommends the adaptation of 0.9 mm casing wax all over except PPS area Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307. 21

22. Sheldon : In the first technique, the primary impression is made with low-fusing modelling compound (Kerr white cake compound). The borders are refined with Kerr green stick compound. Once the operator is satisfied with the retention, selective relief is accomplished by scraping in the region of incisive papilla, rugae , and mid palatal areas Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 22

23. Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 23 In the second technique, he describes of making an alginate primary impression . A primary cast is poured. After analysis of cast contours, undercuts are blocked out. Later , he recommends the placement of spacer or pressure control (bud did not mention clearly about the wax spacer design). Border molding is done with green stick compound before making the secondary impression with ZOE paste [13], based on selective-pressure technique used on high arched palate.

24. Shetty : A thin sheet of wax 0.4 mm major connector wax is required to be placed in all areas except the PPS area, as this area needs to be compressed during the border- molding procedures. A 1.5 mm thick layer of modelling wax is applied on top of the already adapted wax sheet. The modelling wax is removed in the region of the crest of the alveolar ridge and the horizontal palate , as these are stress-bearing areas Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 24

25. Smith’s design: 1 mm thick base-plate wax covers the ridge and midpalatine raphe. Two tissue stops , each at the canine region and exposed hard palate Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 25

26. Miscellaneous design for maxillary arch: Based on minimal-pressure technique, a 1 mm base-plate wax is placed over the basal area except right and left posterior hard palate . Four tissue stoppers , each at canine and molar regions and the exposed areas act as stoppers. The material of choice is rubber Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 26

27. Miscellaneous design for mandibular arch: Based on selective-pressure technique, a 1 mm thick base-plate wax is placed over the entire alveolar ridge except at the retromolar pad area. Tissue stops are placed, each at canine region, bilaterally. Full coverage with tissue stops provides uniform thickness of impression material Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 27

28. Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 28 Partial spacers, like I-spacer and T-spacer, cover specific tissues based on different clinical situations.

29. 29 The careful design and construction of special trays with proper spacer designs may be used to enhance their clinical effectiveness, and thus help the clinician achieve the desired goal . Special trays tended to be used in removable prosthodontics, with equal proportions being used in complete and partial denture cases. Custom trays were requested in only a small number of treatments involving fixed cases PW Smith etal.The design and use of special trays in prosthodontics: guidelines to improve clinical effectiveness BRITISH DENTAL JOURNAL, VOLUME 187, NO. 8, OCTOBER 23 1999

30. Removable prosthodontics 30 In removable prosthodontics, it is important that impressions record the whole of the potential denture-bearing tissues including any teeth involved in the design of the prosthesis . The cast obtained from the primary impression should then allow the fabrication of an appropriately designed customised (special) tray with proper spacer design The design of the custom tray will depend not only upon which material has been chosen for the definitive impression but also the impression technique with proper spacer design PW Smith etal.The design and use of special trays in prosthodontics: guidelines to improve clinical effectiveness BRITISH DENTAL JOURNAL, VOLUME 187, NO. 8, OCTOBER 23 1999

31. Fixed prosthodontics The functional and aesthetic demands of bridge work means that fidelity in the impressions of the prepared teeth and surrounding teeth and soft tissues is essential 31 PW Smith etal.The design and use of special trays in prosthodontics: guidelines to improve clinical effectiveness BRITISH DENTAL JOURNAL, VOLUME 187, NO. 8, OCTOBER 23 1999

32. Special trays with 1.5mm thick baseplate wax may be useful in recording impressions in fixed prosthodontics in the following circumstances: • When there is an unusual distribution of missing teeth • Where the arch form means that a stock tray is a poor fit. In these situations the impression material may be used in sub-optimal thickness, thus producing the potential to create inaccuracies • When the last tooth in the arch is to be included in the preparation. In these circumstances it is not uncommon to produce ‘drags’ in the impression when using stock trays 32 PW Smith etal.The design and use of special trays in prosthodontics: guidelines to improve clinical effectiveness BRITISH DENTAL JOURNAL, VOLUME 187, NO. 8, OCTOBER 23 1999

33. Design characteristics for special trays The dentist should consider the following key aspects of design • The material from which the tray is to be made • The desired extension of the tray • The thickness of any spacer to be placed on the cast • The location of any tissue stops • The position, number and form of any handles. 33

34. 34 PW Smith etal.The design and use of special trays in prosthodontics: guidelines to improve clinical effectiveness BRITISH DENTAL JOURNAL, VOLUME 187, NO. 8, OCTOBER 23 1999

35. 35 PW Smith etal.The design and use of special trays in prosthodontics: guidelines to improve clinical effectiveness BRITISH DENTAL JOURNAL, VOLUME 187, NO. 8, OCTOBER 23 1999

36. Tray materials Several materials are available for custom tray construction, including thermoplastic materials, self curing and heatcuring polymethylmethacrylate resins, and the visible light cured (VLC) dimethacrylate resins. 36 PW Smith etal.The design and use of special trays in prosthodontics: guidelines to improve clinical effectiveness BRITISH DENTAL JOURNAL, VOLUME 187, NO. 8, OCTOBER 23 1999

37. Spacer thickness This is determined by the material to be used in making the definitive impression. It is an important specification as the impression material to be used then has an optimal even thickness to help improve dimensional accuracy, while also ensuring that the loaded tray is not too bulky, allowing ease of placement in the mouth It may indicate that the supporting tissues are recorded in a particular state of displacement . 37 PW Smith etal.The design and use of special trays in prosthodontics: guidelines to improve clinical effectiveness BRITISH DENTAL JOURNAL, VOLUME 187, NO. 8, OCTOBER 23 1999

38. Tissue stops They are not essential in all cases , In some complete denture impressions owing to the compressibility of the supporting mucosa. I n fixed prosthodontics to act as locating stops when using fairly fluid impression materials. They should ideally be located at three widely spaced points around the arch, and placed with care to avoid including the teeth to be prepared. PW Smith etal.The design and use of special trays in prosthodontics: guidelines to improve clinical effectiveness BRITISH DENTAL JOURNAL, VOLUME 187, NO. 8, OCTOBER 23 1999 38

39. Fabrication Of The Custom Impression Tray https://www.dentistrytoday.com/the-custom-impression-tray-fabrication-and-utilization/ 39

40. A tripathi etal , A technique to preserve spacer thickness during custom tray fabrication with autopolymerizing polymethylmethacrylateInternational Journal of Dentistry Research 2017; 2(1): 1-2 40 A technique to preserve spacer thickness during custom tray fabrication with autopolymerizing polymethylmethacrylate Arvind Tripathi , Saumyendra V. Singh , Himanshi Aggarwal , Ashutosh Gupta , Deeksha Arya Describes a simple technique to prevent change of thickness of wax spacer during custom tray fabrication with autopolymerizing PMMA.

41. 41 Adapted wax spacer on preliminary cast Cellulose acetate sheet adapted I mm short of wax spacer Wax spacer removed and its thickness measured with Iwanson’s gauge A tripathi etal , A technique to preserve spacer thickness during custom tray fabrication with autopolymerizing polymethylmethacrylateInternational Journal of Dentistry Research 2017; 2(1): 1-2

42. Kaur , H., Nanda, A., Verma , M., & Koli , D. (2016).  Technique for adapting a spacer for a custom impression tray. The Journal of Prosthetic Dentistry, 116(6), 851–852. 42 Technique for adapting a spacer for a custom impression tray Harsimran Kaur , MDS,a Aditi Nanda, MDS,b Mahesh Verma , PhD,c and Dheeraj Koli , MDS Maulana Azad Institute of Dental Sciences, New Delhi, India An alternate technique for adapting the spacer, which overcomes the limitations of conventionally used wax spacers, is presented. The recommended spacer is 1.3 mm for light-body elastomer, 3 mm for medium-body elastomer, 0.5 mm for metal oxide paste, and 3.0 mm for irreversible hydrocolloid.

43. Kaur , H., Nanda, A., Verma , M., & Koli , D. (2016).  Technique for adapting a spacer for a custom impression tray. The Journal of Prosthetic Dentistry, 116(6), 851–852 43 Primary cast with adapted thermoplastic vacuum-formed spacer within previously marked outline Peeling off spacer after border molding before definitive impression making. Completed custom tray fabricated over spacer

44. Rupal J etal Complete Denture Impression Procedures and Techniques Practiced by Dentists across the State of Gujarat: A Survey Journal of Dental and Medical Sciences .Volume 14, Issue 6 Ver. V (Jun. 2015 44 The predominantly used impression philosophy for final impressions turned out to be selective pressure (91 %) 66% used both spacers and relief holes, 18% made only relief holes, 11% made relief holes but used spacers in select cases only, while the remaining 5% used only spacers. Complete Denture Impression Procedures and Techniques Practiced by Dentists across the State of Gujarat: A Survey Dr. Rupal J. Shah1 , Dr. Sanjay B. Lagdive2 , Dr. Prakash K. Barajod3 , Dr. Maulik N. Patel Journal of Dental and Medical Sciences .Volume 14, Issue 6 Ver. V (Jun. 2015)

45. Conclusion 45 T he success of complete dentures largely depends on accuracy of impression. While making impression, one should apply pressure selectively only in certain areas, which can withstand the forces of mastication to minimize the possibility of soft-tissue abuse and bone resorption . This review shows that a wide range of spacer design is available for different situations. Based on the particular condition, the dentist needs to select spacer design for the success of complete denture therapy

46. 46 Reference: Yogeshwari , Aeran H Different spacer designs in complete denture prosthodontics; Guident 2021 Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh) 8: 307 Dr Aruna J, Bhandari I etal Spacer designs for impression techniques in conventional complete dentures;VIMS health science jrnl;vol:4;no.1 march 2017 PW Smith etal.The design and use of special trays in prosthodontics: guidelines to improve clinical effectiveness BRITISH DENTAL JOURNAL, VOLUME 187, NO. 8, OCTOBER 23 1999 A tripathi etal , A technique to preserve spacer thickness during custom tray fabrication with autopolymerizing polymethylmethacrylateInternational Journal of Dentistry Research 2017; 2(1): 1-2 https://www.dentistrytoday.com/the-custom-impression-tray-fabrication-and-utilization / Kaur , H., Nanda, A., Verma , M., & Koli , D. (2016). Technique for adapting a spacer for a custom impression tray. The Journal of Prosthetic Dentistry, 116(6), 851–852 Rupal J etal Complete Denture Impression Procedures and Techniques Practiced by Dentists across the State of Gujarat: A Survey Journal of Dental and Medical Sciences .Volume 14, Issue 6 Ver. V (Jun. 2015

47. 47 Cross References: 1. Boucher CO (1951) A critical analysis of mid-century impression techniques for full dentures. J Prosthet Dent 1: 472-490. 2 . Zinner ID, Sherman H (1981) An analysis of the development of complete denture impression techniques. J Prosthet Dent 46: 242-249. 3 . Zarb GA, Bolender CL, Carlsson GE (1999) Boucher’s Prosthodontic Treatment for Edentulous Patients. 11th ed. St. Louis, MO: Mosby, pp. 3123-3123. 4 . Morrow RM, Rudd KD, Rhoads JE (1986) Dental Laboratory Procedures, Complete Dentures, Vol. 1, 2nd ed. Toronto: CV Mosby, pp. 26-56. 5 . Hickey JC, Zarb GA, Bolender CL (1985) Bouchers Prosthodontic Treatment for Edentulous Patients. 9th ed. St. Louis, MO: CV Mosby Company, 119-230. 6 . Grant AA, Heath JR, McCord JF (1992) Complete Prosthodontics. London: Mosby-Year Book Europe Limited, pp. 89-93. 7 . Sharry JJ (1974) Complete Denture Prosthodontics, 3rd ed. New York: Blakiston , pp. 191-210. 8 . Bernard L (1984) Impressions for Complete Dentures. Chicago, IL: Quintessence, pp. 71-90.

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