Final support
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This document discusses support for complete dentures. It defines support as the foundation area on which a dental prosthesis rests and its resistance to displacement from underlying structures. The maxilla and mandible have different primary support areas, like the palate and buccal shelf area, respectively. Proper impression techniques and occlusal schemes can help maximize support by distributing forces evenly over broad areas. Understanding the anatomy and properties of supporting tissues is essential for fabricating dentures with good longevity and minimizing resorption or trauma.
Final support
- 2. Support In Complete Denture Guided By- Dr S.R Godbole Dr Sweta Pisulkar Dr Trupti Dahane Presented By- Rohit Ashok Mistry JR- 1 Department Of Prosthodontics, Crown & Bridge
- 3. Content • Introduction • Definition • Review Of Literature • Aspects Of Complete Denture Support • Snow shoe Effect • Anatomic Considerations Maxillary and Mandibular arch • Relief Areas • Practical Considerations • Impression making • Occlusal Scheme
- 5. Retention •Psychologic Comfort Support •Longetivity Success Of Prosthesis Stability •Physiologic Comfort Certain Biological, Mechanical and Physical Properties Provide T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 1, JPD Jan 1983 ACCORDING TO JACOBSON
- 6. Definition Support: The foundation area on which a dental prosthesis rests. With respect to dental prostheses, the resistance to displacement away from the basal tissue or underlying structures. (According to GPT-9)
- 7. Review Of Literature • Greene Brothers (1874) : introduced the muco-compressive technique to record impression under pressure using modelling compound • Page H L (1938) : recommended that all the tissue must be recorded at rest, was the proponent of mucostatic impression technique. • Swenson (1947): tissue placement for equalization of pressure in order to resist occlusal stress over the entire bearing area is desirable. • Craddock (1951): coined the term “Pear Shaped Pads” and stated that the retromolar pad is not a favourable denture bearing area.
- 8. • Maison (1955) : Maximum coverage and flange extension, Equitably distribute the occlusal load over the greatest possible area. Extend a well-defined periphery to within the limits of tissue tolerance, to gain lateral denture stability and valve seal. • Atwood (1962): Clinical joy over big ridges must be tempered with the sober realization of the greater potential bone loss over the years of future edentulousness. • Van Scooter and Boucher(1965): described the histology of palate in detail and gave reasons for its use as primary support area.
- 9. Aspect of Support T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983 Support may be considered from two point of view The Duration for which this relation ship is maintained Dentures must conform to the underlying tissue
- 10. How can this be achieved? T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983 Perpendicular Forces Directed Towards area which resist remodelling under pressure Using Impression Procedures that provide extension and functional loading of tissues with varying resiliency
- 11. Friable tissue Area covered without impingement Resistant to resorption Checklist to Effective Support T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983 Area Available Resistant to resorption Effective Support Cover maximal surface Select tissue which are resistant to resorption Provide relief to tissue which have varying resiliency
- 12. Snow Shoe Principle • Given a Constant occlusal force, a broader denture bearing area decreases the stress per unit area under the denture base, decreases tissue displacement, and reduces denture base movement T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983
- 14. Anatomy of the supporting structures Area of the denture bearing surface : Maxilla- 24cm2 Mandible- 14cm2 Capability To Bear Force Maxilla >Mandible
- 15. Nature of supporting tissue • Soft Tissue characteristics • Keratinized firmly bound mucosa • Presence of resilient submucosa • Presence of firmly bound connective tissue • Hard Tissue Characteristics • Bone resistant to resorption and remodelling • Use of cortical bone in support of complete dentures The choice of bone support is explained well by Wolff’s law of remodelling and the pressure tension theory. T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983
- 16. Histology
- 17. Mucosa types Mucosa good for support Mucosa which needs relief Horizontal slope of Palate, Buccal Shelf Area. Mid Palatine suture Area
- 18. Oral Mucous Membrane Rhonda F. Jacob,Zarb,Prosthodontic treatment For Edentulous Patient, Bouchers 13th SA Ed Contact and extension of the static intaglio and cameo surface of the dentures is a composite of the adjacent tissues at rest and in function. The Intaglio surface of the denture comprises of two areas: • Stress bearing (Supporting) • Limiting areas
- 19. “Since the success of the complete denture depends largely on the relation of the dentures to anatomic structures which support and limit them, familiarity with the location and character of these structures is essential.” -Edwards & Boucher
- 20. Stress Bearing Areas Maxilla • Primary -Anterolateral slopes of hard palate -Maxillary tuberosity • Secondary -Palatal Rugae -Residual Alveolar Ridge -Maxillary tuberosity Mandible • Primary -Buccal Shelf Area -Retromolar Pads • Secondary -Crest Of Alveolar Ridge Rhonda F. Jacob,Zarb,Prosthodontic treatment For Edentulous Patient, Bouchers 13th SA Ed
- 21. Mandibular Anatomical Consideration Rhonda F. Jacob,Zarb,Prosthodontic treatment For Edentulous Patient, Bouchers 13th SA Ed
- 22. Buccal Shelf Area Primary stress bearing areas in mandible
- 23. Rationale Thick Submucosa Vertical forces are perpendicularly acting Dense corticated bone Fibres of buccinator lie horizontally to the area Rhonda F. Jacob,Zarb,Prosthodontic treatment For Edentulous Patient, Bouchers 13th SA Ed Primary stress bearing areas in mandible
- 24. Retromolar pads Pear Shaped Pad • Distal extent of keratinized masticatory mucosa • Formed by scaring of extracted 3rd molar and its retromolar papilla. • The pear-shaped pad area is associated with muscle and/or tendinous attachments of the buccinator, superior constrictor, and temporal muscles. Retromolar pad • Triangular soft pad of tissue at distal end of lower ridge. • Mucosa-composed of thin, nonkeratinized epithelium Loose alveolar tissue • Submucosa-glandular tissue • fibers –buccinator superior, constrictor temporalis muscle,pterygomandibular raphe T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983 Primary stress bearing areas in mandible
- 25. H i s t o l o g i c a l D r a w i n g O f T h e R e t ro m o l a r P a d s Boucher's prosthodontic treatment for edentulous patients 9th ed 1985.
- 26. Retromolar pads Primary stress bearing areas in mandible
- 27. Crest of Alveolar Ridge • Presence of Cancellous bone • Less Keratinized Mucosa Boucher's prosthodontic treatment for edentulous patients 9th ed 1985. Histological Drawing of the Lower Residual Ridge Mucosa
- 28. The Remaining Anatomy • The remaining anatomic regions of the mandible are not usually essential in providing denture support. • The less keratinized alveolar mucosa of the lingual and anterior labial ridge slope lies directly over basal slope and does not tolerate pressure well. • The denture borders are extended in the movable soft tissue to effect border seal and not to promote support. • Genial tubercle- A possible area of support T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983
- 29. Overview Of Mandible Support Areas T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983 1˚- Primary 2˚- Secondary R- Relief N/C- Non-Contributing
- 30. Maxillary Anatomic Consideration Rhonda F. Jacob,Zarb,Prosthodontic treatment For Edentulous Patient, Bouchers 13th SA Ed
- 31. The Hard and soft palate DONALD E. VAN SCOTTER, THE NATURE OF Supporting TISSUES FOR COMPLETE DENTURES, JPD MARCH-APRIL 1965, 285-294 Primary stress bearing areas in mandible
- 32. Horizontal Slopes Of hard Palate • Keratinized masticatory mucosa • Distinct submucosal layer underlying the epithelium (except the mid- palatine suture area) • Cortical bone of the palatine processes resist resorptive changes • Dense band of connective tissue in the mid palatine raphe region In a flat or low palate the amount of spongy bone is greater than in a high palate. DONALD E. VAN SCOTTER, THE NATURE OF Supporting TISSUES FOR COMPLETE DENTURES, JPD MARCH-APRIL 1965, 285- 294 Primary stress bearing areas in mandible
- 33. Postero-lateral part of hard palate (Large quantity of Glandular tissue) Antero-lateral part of hard palate (Large quantity of adipose tissue) Mid- palatine suture (thin submucosal layer) Region of Incisive Papilla (shows nerves and vessels) Primary stress bearing areas in mandible Boucher's prosthodontic treatment for edentulous patients 9th ed 1985.
- 34. Crest Of Alveolar Ridge • Thick Keratinized Mucosa • Firmly bound to the underlying periosteum and bone • The underlying bone is cancellous and undergoes resorptive changes on functional stress Boucher's prosthodontic treatment for edentulous patients 9th ed 1985. Submucosal layer sufficiently thick to provide resiliency
- 35. Tuberosity • Dense fibrous connective tissue • Minimal compressibility • Offers secondary support. Boucher's prosthodontic treatment for edentulous patients 9th ed 1985.
- 36. Palatine Rugae • Increased surface area • Resistance to antero-posterior movement of the denture • Acts as a secondary support area
- 37. Overview Of Maxillary Support Area T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983
- 38. T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983 Tissues that are susceptible to resorption. Tissues that have thin mucosa overlying cortical bone. Mucosa which contains underlying neurovascular bundle or sensitive structures. Relief Areas
- 39. Practical Consideration • Impression making • Occlusion T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983
- 40. Impression making Theories Pressure less Group (mucostatic) Richardson Pressure Group (Greene Brothers) Mucocompressive Selective Pressure Group (Boucher’s) Properties Theory based on Mucostatic theory (based on Pascal’s law) sets out to record the mucosa in its static (supported by underlying basal bone), undisturbed form This concept seeks to subject the tissues to a continuous pressure Based on the fact that there are variation in displaceability of supporting tissue and thus the need for selective pressure HOW? Use of mucostatic impression material (impression plaster) Use of impression compound, waxes and soft liners altering the spacer thickness and hence material thickness Questions raised? Such an impression will not cover enough area as no border moulding (Depends on the intimate contact and short range forces) conducive to resorptive changes Displacement of Dentures in tissues attempt to return to their original form Thickness of spacer and impression material does not gurantee selective pressure Control over finger pressure Occlusal load distribution Shefali Singla, Complete denture impression techniques: Evidence-based or philosophical, Indian J Dent Res, 18(3), 2007
- 41. Questioning Selective Impression Technique 1. Can we alter the pressure by simply changing the thickness of spacer/ impression material in a loaded tray? Bone reacts to the slight distortion caused by pressure in the form of elastic forces which resist compression. 2. Can we control the Finger pressure, thereby choosing a particular area of the basal seat to receive excess load? The finger pressure cannot be controlled. 3. Can the load received at occlusal surfaces be selectively distributed or does it get transferred uniformly over the seat? It gets distributed throughout the denture bearing area Shefali Singla, Complete denture impression techniques: Evidence-based or philosophical, Indian J Dent Res, 18(3), 2007
- 42. Spacer Designs and Support Boucher’s Design J J Sharry’s Design Rudd, Morrow, Rhodes Design Jain AR, Dhanraj M (2016) A Clinical Review of Spacer Design for Conventional Complete Denture. Biol Med (Aligarh)
- 43. Studies on Occlusal Schemes • AN in-vitro study compared the pressure values on the supporting tissue using three different posterior occlusal schemes: Balanced occlusion, lingualized occlusion, and monoplane occlusion in simulated dentures. Monoplane < Completely Balanced < Lingualized Occlusion Madalli P, Murali CR, Subhas S, Garg S, Shahi P, Parasher P. Effect of occlusal scheme on the pressure distribution of complete denture supporting tissues: An in vitro study. J Int Oral Health 2015;7 (Suppl 2):68-73.
- 44. • FRANK, conducted a study to determine the effect of tray modifications & selection of impression materials on pressures exerted on the denture supporting tissues . Conclusion: More pressures were measured at the crest of the ridge than on the palate when no relief was used. Use of escape vents or relief was equally effective in decreasing pressures & equalizing the pressures on the ridge crest ,palatal area. T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD Jan 1983
- 45. Morbidity Associated with complete denture • Residual Ridge Resorption • Denture Stomatitis • Flabby Tissue (Maxilla 24% mandible 5%) • Combination Syndrome • Denture Irritation Hyperplasia (5%) • Traumatic Ulcer (7%) • Temporomandibular Joint Disorders Gunnar E. Carlsson, Clinical morbidity and sequelae of treatment with complete dentures, (J Prosthet Dent 1997;79:17-23.)
- 46. Summary • Support is one of the essential requirement in fabrication of complete denture. • The knowledge of denture supporting tissue is important is fabricating a denture which has good longevity • Various methods, technique are to be used in order to achieve maximum support. • Dentists must base their technique on an understanding of biologic aspects of the relationship between the denture base and the supporting tissue.
- 47. References • T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 1, JPD jan 1983 • T. E. Jacobson& A. J. Krol, A contemporary review of the factors involved in complete denture retention, stability, and support, PART 3, JPD jan 1983. • Shefali singla, complete denture impression techniques: evidence-based or philosophical, indian j dent res, 18(3), 2007 • Jain AR, dhanraj M (2016) A clinical review of spacer design for conventional complete denture. Biol med (aligarh) • Boucher's prosthodontic treatment for edentulous patients 9th ed 1985. • Donald e. Van scotter, The nature of supporting tissues for complete dentures, jpd march- april 1965, 285-294 • Rhonda f. Jacob,zarb,prosthodontic treatment for edentulous patient, bouchers 13th SA ed • Gunnar E. Carlsson, Clinical morbidity and sequelae of treatment with complete dentures, (J Prosthet Dent 1997;79:17-23.)
- 48. Thankyou!
Editor's Notes
- #5: Retention-Complete denture retention is the resistance to displacement of denture base away from the ridge Stability- it is the resistance to horizontal and rotational forces preventing lateral or anterio-posterior shunting of denture base Support- denture support is the resistance to vertical movement of the denture base towards the ridge.
- #8: Although the broad, high ridge may have a greater potential bone loss, the rate of vertical bone loss may actually be slower than that of a small ridge because there is more bone to be resorbed per unit of time and because the rate of resorption also depends on the density of the bone.
- #10: The denture must conform to the underlying tissue so that the occlusal surface can correctly oppose on eanother at the time of insertion It is vital that this is maintained for a period of duration The reason why retention and stability aids support
- #12: Cover Maximal surface. Choose tissue which resist resorption Establish form contact to the tissues which are resistant to resorption Compensate for tissues which are friable under function and to maintain harmonious occlusal relation ship
- #15: After determining the outline for of the total denture bearing area, one must study the nature of the supporting tissue contained within the border
- #16: The nature of supporting tissue, it can be discussed under the heading which have been mentioned that is the soft and the hard tissue..or another way is to go from the most superficial layer to the deepest…. Keratin is a scleroprotein which is produced by epithelium on maturation, it renders the epithelial layer strength and resiliency. The submucosa which is present underneath the mucosa provides with cushioning effect this effect is magnified on [resence of submucosal structures like salivary gland. In some areas of the masticatory mucosa there is absence of submucosa and thus the mucosa is firmly bound to the periosteum by mean od thick bands of connective tissue. These bands of connective tissue prevent the direct pressure on the underlying bone and thus is a beneficial feature. The hard tissues which are underlying the denture bearing area must be relatively resistant to resorption and remodelling, although presence of few natural teeth helps in conserving the amount of bone. It is important to minimize pressure in areas which are prone to resorption in order to preserve the ridge in good health in completely edentulous patients. The use of cortical bone in support of complete denture permits the prosthesis to maintain its recorded relationship to the edentulous ridge over a longer period of time. The bottom line being that firm keratinized mucosa bound to underlying cortical bone with a variable zone of connective tissue is nd associated with muscle attachment provides ideal bearing area
- #18: On the left there is mucosa which has a thick submucosal layer, the thick submucosa is more efficient in beating the stress exerted by the dentures, on the other side there is representation of mucosa covering the mid-palatine raphe area where less or negligible amount of submucosa may be present. Other regions which require relief on account of its histological nature is the fovea palatine, nasopalatine area due to nasopalatine nerves and vessels. A detailed discussion of the mucosal consideration is to follow further.
- #19: When it comes to denture fabrication the mucosa which maximum contributes to support is the masticatory mucosa with the exception of parts of soft palate and parts of mucogingival junction which establishes the seal
- #23: Boundaries and Extent- Area between the mandibular buccal frenum and the anterior edge of the masseter muscle. Medially- crest of the ridge Laterally- bony external oblique ridge Distally- retromolar pads
- #24: The buccinator fibres attach horizontally along the bony oblique ridge. As the resorption of the ridge occurs, the buccal shelf area does not resorb because of its muscle attachment on its posterior and lateral borders. The shelf is dense and cortical and lies at a right angle to vertical occlusal forces and is therefore a primary stress bearing area
- #25: Clinicians must recognize the differences between the pear-shaped pad and the retromolar pad based on anatomic location and histologic composition. Frequently, the entire area of the distal ridge crest is referred to as retromolar pad. This leads to confusion in determining the mandibular denture extension. Pear Shaped Pad(term was first given by craddocl)- The deep and superficial tendons of the temporal muscles insert medially and laterally in the mandible at the posterior border of the pear-shaped pad. Such muscle attachments and the overlying, firmly bound masticatory mucosa provide a stress-bearing region that is relativelyresistant to resorptive changes. If the mandibular denture is short of this region, there will be more rapid resorption of the distal alveolar ridge and a resulting settling of the denture base posteriorly
- #27: The retromolar pad is a triangular pad of tissue at the distal end of the residual ridge. According to Jacobson the retromolar pad is not a favourable denture bearing area . The junction of the pear shaped and retromolar pad demarcates the distal border of a properly extended mandibular complete denture.
- #28: Histologic drawing shows the submucosal layer to be adequate thickness and firmly attached to the ridge. However bone that forms crest of lower ridge is cancellous, or spongy in nature , there fore this part cannot ve used for primary support
- #29: The genial tubercle can be used as a support if thick mucosa is present over the area, patients who have undergone vestibuloplasty procedure with split thickness graft have favourable mucosa overlying the genial tubercle area
- #30: Relative importance of various anatomic regions of mandible in providing denture support. Primary support areas must include the buccal shef areas and the pear shaped pads. Ridge crest and areas of genial tubercle may be treated as secondary support areas. lingual and labial areas are non-contributing.
- #31: Add a note on RUGAE
- #32: The figure on right shows the drawing of mucosa of the hard and soft palate Figure on the right shows stress bearing areas of the maxillary arch
- #33: Resiliency of the submucosal layer acts as a cushion for the functional stresses transmitted to the mucosa The dense connective tissue band which traverses in the mid-palatine region adheres the mucosa to the underlying periosteum, there must be relief in this area as to avoid undue pressure and creation of fulcrum at this area
- #35: Rapid resorption involving the anterior maxillary ridge beneath a complete denture opposed by mandibular anterior natural dentition is frequently seethe forces must be controlled and minimized by proper design and technique
- #36: Tuberosities are considered secondary stress bearing areas as these are firm swellings do provide stability to the denture and prevent its rotational movement or any horizontal forces unseating the dentures
- #37: anatomic fold or wrinkled usually used in the plural sense; the irregular fibrous connective tissue ridges located in the anterior third of the hard palate. Irregular elevations or rugae extend anterolaterally from the palatine raphe. According to Lund, the rugae are not simple elevations of the mucous membrane, but contain as their base a connective tissue nucleus called “ruga nucleus.” This consists of a tissue of embryonic character, rich in cells and interwoven with very delicate connective tissue fibers. The disappearance of the rugae in later life is apparently due to the decrease of submucous adipose tissue, rather than shrinkage of the ruga nucleus. 21 The rugae may have a mechanical function during the suckling age, but are rudimentary in man, probably because of the soft nature of his food.
- #39: Say Something About FOVEA PALATINi In patients with thick ropy saliva, the fovea palatinae should be left uncovered or else the thick saliva flowing between the tissue and the denture can increase the hydrostatic pressure and displace the denture.
- #40: The two most important steps which will help in acquiring maximum support during complete denture fabrication is impression making and occlusal schemes
- #41: Boucher CO (1951) A critical analysis of mid-century impression techniques for complete dentures. J Prosthet Dent 1(4):472–491 Can we alter the pressure by simply changing the thickness of spacer / impression material Can we control the finger pressure, thereby choosing a particular area of the basal seat to receive excess load? Can the load received at occlusal surfaces be selectively distributed or does it get transferred uniformly over the seat?
- #42: The physics behind providing spacer clearly takes into account that pressure be excreted on the areas where the trays are in contact with the base directly(primary stress bearing area), but the question is the stress bearing area also has some compressibility and resiliency and it would be an underestimation that the pressure applied on the tray does not affect these tissues. The pressure applied by the finger is not controlled…there may be delivery of force which compresses the tissue overall or none at all Eventually after the fabrication of a denture base during function. the occlusal stress
- #43: Sharry, based on minimal-pressure technique, recommends adaptation of a layer of base-plate wax over the whole area outlined for tray (even in PPS area) 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. Morrow, Rudd, and Rhoads, based on minimal-pressure technique, recommend blocking out undercut areas with wax and then
- #46: Though the sequale of ill fitting denture is multifactorial but the ultimate effect is reflected in the tissues that support the denture and the TMJ.