Denture border evaluation /certified fixed orthodontic courses by Indian dental academy


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Denture border evaluation /certified fixed orthodontic courses by Indian dental academy

  3. 3. MAXILLARY & MANDIBULAR EDENTULOUS FOUNDATIONS: Knowledge of oral anatomy helps the operator in understanding the landmarks that serve as positive guides in Prosthodontic procedures . DEFINITION :Denture bearing areas or Denture foundation area or Basal seat —the surface of the oral structures available to support a denture.(GPT-8) Denture bearing area- maxilla 24 cm2 & mandible 14 cm2 (Dr WATT surgeon.) The impression surface/Fitting surface1.stress-bearing/supporting areas. 2.peripheral/limiting areas.
  4. 4. STRESS-BEARING AREA. • PRIMARY. • Hard palate.(max) • Buccal shelf.(man) • SECONDARY. • Rugae .(max). • Slopes of residual ridge .(man).
  5. 5. Supporting areas. • PRIMARY. • Horizontal portion of Hard palate . (max)& Rugae • Buccal shelf (man) • SECONDARY. • Crest of residual ridge. (max) • Slopes of residual ridge. (man)
  6. 6. RELIEF AREAS. • MAXILLA. • Medial palatal suture. • Incisive foramen. • Sharp bony projection. • Rugae – valley. • MANDIBLE. • Crest of residual ridge. • Sharp bony projection. • Mental foramen. • Genial tubercle. • Mylohyoid ridge.
  7. 7. Maxillary arch Labial frenum: • Fold of mucous membrane at the median line. • Moves with muscles of lip. • Adequate relief for muscle activity. • Proper denture seal. • Excessive relief weakens denture base. •A- correct contour •B –incorrect contour. •C- area should have been covered. Labial notch
  8. 8. Buccal frenum:  Single or double folds of mucous membrane.  Broad and fan shaped.  Moves with muscles of cheek during speech and mastication.  Adequate relief for muscle activity-more clearence. Buccal notch •Maxillary buccal frenum area. •Denture border contour in buccal frenum area.
  9. 9. Labial vestibule • Labial-buccal frenum. • Muco-gingival linelimits upper border. • Record adequate depth/width. • Overextension causes instability/soreness. •Labial flange • Proper contouring gives optimal esthetics.
  10. 10. Buccal vestibule • Buccal frenum to hamular notch. • Record adequate depth/width. • Improper extension causes instability/soreness. Buccal flange
  11. 11. Maxillary tuberosity. • Distal end of denture must have Coveragestability/retention. Area of tuberosity • Gross enlargement(fibrou s or bony –surgical correction.
  12. 12. Hamular notch. •Distal to maxillary tuberosity •Aids in locating posterior palatal seal. •Overextension causes soreness. Area of hamular notch
  13. 13. PPS-the seal area at the posterior border of a maxillary removabledentalprosthesis.(GPT-8) PPS OR POST PALATAL SEAL 0R POST DAMThe soft tissue along the junction of the hard and soft palates on which pressure with in the physiologic limits of the tissues can be applied by a denture to aid in the retention of the denture. (Winkler) • • • VIBERATING LINE-an imaginary line across the posterior part of the palate marking the division between the movable and immovable tissues of the soft palate. this can be identified when the movable tissues are functioning. The anterior vibrating line is an imaginary line located at the junction of the attached tissues overlying the hard palate and movable tissues of the immediately adjacent soft palate.(valsalva maneuver –method) The posterior vibrating line is an imaginary line at junction of the aponeurosis of the tensor veli palatini muscle and the muscular portion of the soft palate.
  14. 14. Vibrating line: • Junction of movable and immovable part of soft palate. • 2mm ant to fovea palatinae. • Aids to establish PPS. • Distal end of denture at least to vibrating line. Post palatal seal area. • From hamular notch to hamular notch. • Anterior to vibrating line. • Aids in retention. .
  15. 15. Fovea Palatinae. • Bilateral indentations near the midline of palate. • Formed by coalescence of several mucous gland ducts. • Posterior to junction of hard and soft palate. • Aids in determining vibrating line.
  16. 16. Hard palate • Support for the maxillary denture. • Primary stress bearing areahorizontal portion of hard palate lateral to midline. • Secondary stress bearing area – rugae.
  17. 17. Alveloar ridge • . Alveolar groove
  18. 18. Incisive papilla. • Elevation of soft tissue over the incisive foramen or nasopalatine canal. • Location : on or labial to ridge. • Impingement –burning •Incisive fossa sensation, parasthesia and pain. • Relief necessary.
  19. 19. Rugae. • Irregular shaped rolls of soft tissue. • Secondary stress bearing area. • Should not be distorted in the impression.
  20. 20. Median palatine raphae. • Extends from incisive papilla to distal end of hard palate. • Thin mucosal covering and non-resilient.. • Relieve adequately to avoid trauma from denture base. Median palatine groove
  21. 21. Mandibular arch. Labial frenum. • Shorter and wider than the maxillary frenum. • Adequate relief for muscle activity (mentalis). • Proper fit around it maintains seal’. Labial notch.
  22. 22. Buccal frenum. • Adequate relief for muscle activity. • Proper denture seal. Buccal notch.
  23. 23. Labial vestibule. • Labial-buccal frenum. • Overextension causes instability/soreness. • Muscles attachment close to the crest of the ridge- limits the denture flange extension. • Mucolabial fold limits the depth of the flange. • Record adequate depth and width. Labial flange • Proper contouring gives optimal esthetics.
  24. 24. Buccal vestibule. • Buccal frenumretromolar pad. • Record adequate depth and width. • Impression is widest in this area. Buccal flange
  25. 25. Buccal shelf • .
  26. 26. Def..Anatomically buccal shelf is defined as the part of the basal seat located posterior to the buccal frenum.(Boucher 10 th edition). • The area between the mandibular buccal frenum and the anterior edges of masseter muscle is known as buccal shelf(b12) Boundaries: • Anteriorly-buccal frenum. • Posteriorly-retromolar pad. • Medially-crest of the ridge • Laterally-external oblique ridge. Width-4-6 mm wide on average mandible. • 2-3 mm or less in narrow mandible. • The total widthof the bony foundation in this region becomes greater as alveolar bone resorption continues.the reason is that the inferior border of the mandible is great than the width at the alveolar process. Clinical implication: upper slopes of the buccal shelf adjacent to the pad helps to resist the distal dis placement of the denture because of the diminished available support,a narrow mandible is usually considered the most difficult to manage. • Clinically care should be taken to cover the area
  27. 27. • Interpreting the buccal shelf area:While recording the final impression additonal load is applied in this area,the trays comes in to direct cotact with the mucosa. • Preprosthetic surgery:no • When the residual ridge becomes flat the buccinator is often attached to the center of the ridge.the buccinator muscle can be covered by the denture in this area because the muscle fibres run anterioposteriorly parallel to the bone and the denture does not resist the contracting forces of the muscles.the inferior part of the buccinator is attached to the buccal shelf of the mandible and the contraction of the muscle doesnot lift the denture.(resorbtion • Resisted by horizontal fibres of buccinator
  28. 28. Histology: mucous membrane-is more loosely attached and less keratinised than the mucous membrane covering the crest of the ridge. • Submucosa:thicker,fibres of buccinator are found running horizontally in the submucosa immediately overlying the bone. • The mm overlying the buccal shelf may not be suitable histologically to provide primary support for the denture as the mm overlying the crest of the ridge. • Bone:bs is covered by layer of smooth compact boneor cortical bone(with it’s haversian system,the bone is very dense and the trbaculae are arranged almost at right angles to the jaw closure) plus the fact that the bucal shelf lies at right angles to the vertical occlusal forces,therfore it is more suitable primary stress bearing area for the lower denture.
  29. 29. • Blood supply—artery supply—buccal artery,inferior alveolar artery,nerve supply— buccal nerve ,inferior alveolar nerve,buccal branch of mandibular nerve. • Oralucousmembrane thick ness--mucous membrane-is more loosely attached and less keratinised than the mucous membrane covering the crest of the ridge. • Muscle found in this area—inferior part of the buccinator,anterior edge of the masseter muscle.
  30. 30. External oblique ridge. • A bony ridge runs antero-posteriorly outside the buccal shelf. • Denture border 1-2 mm beyond this ridge. • Shows as Groove in impression.
  31. 31. Alveolar ridge • Residual bone with mucous membrane. • Crest to be relieved. • Buccal and lingual slopes are secondary stress bearing areas.
  32. 32. Retromolar pad. Retromolar fossa • Triangular soft pad of tissue. • Posterior end of lower edentulous ridge. • Limiting landmark of distal extension of complete denture upto ant 2/3 rd of retro molar pad. • Determines height and width of the occlusal table. • Contents-loose connective tissue, glandular tissue ,laterallybuccinator,posterio rly temporalis tendon, medially superior constrictor and pterygo mandibular raphe
  33. 33. Alveolo-Lingual sulcus. Premylohyoid eminence Lingual flange • Between lingual frenum to retromylohyoid curtain. • Anterior region• Premylohyoid fossapremylohyoid eminence in impression. • Border of Impression to make contact with the mucosa of the floor of the mouth when tongue touches the upper incisor. • Overextension causes soreness and instability.
  34. 34. Middle region. • From pre-mylohyoid fossa to the distal end of the mylohyoid ridge. • Lingual flange extends below the level of the mylohyoid ridge- tongue rests on the top of flange and aids in stabilizing the lower denture. • To record ask the patient to touch the buccal mucosa on either side of cheek with tip of the tongue.
  35. 35. Posterior region. • The flange passes into the retromylohyoid fossa. • Proper recording gives typical S –form of the lingual flange.
  36. 36. Retromylohyoid fossa. • Distal end of lingual sulcus. • Area posterior to the mylohyoid muscle. • Good seal aids in Retromylohyoid eminence retention and stability. • To record –ask the patient to protrude the tongue
  37. 37. BOUNDARIES OF LATERAL THROAT FORM. • • • • • Anteriorly –mylohyoid muscle Laterally –pear shaped pad Posteriolaterally-superior constrictors and Posteromedially –palatoglossus The posterior limit of the mandibular denture is determined mainly by the palatoglossal muscle and by superior constrictor muscle-this area is called as retro myelohyoid curtain.
  38. 38. Mylohyoid ridge. • Attachment for the mylohyoid muscle. • Sharp or irregular covered by the mucous membrane. • Trauma from denture base –relief necessary.
  39. 39. Mylohyoid muscle. • Floor of the mouth is formed by mylohyoid muscle. • Lies deep to the sublingual gland in the anterior regiondoes not affect the border of denture. • Posterior region – affects the lingual border in swallowing and tongue movements.
  40. 40. Genial tubercle. • Area of muscle attachment (Genioglossus and Geniohyoid). • Lies away from the crest of the ridge. • Prominent in Resorbed ridges. • Adequate relief to be provided.
  41. 41. JANKELSON in 1962-Adjustments necessary 1.DYNAMIC PHYSIOLOGY 2.FACTORS WITH MATERIALS &TECHNIQUES PRESSURE AREAS-1.Basal surface 2.Intaglio surface 3.Denture peripheries
  42. 42. Common methods of border evaluation Visual &tactile method Methods employing indicator paste Disclosing wax methods
  43. 43. VISUAL-TACTILE METHOD • Experienced operators • Selective activation of facial musculature/tipping forces to denture • Identify areas of over extension/under extension • Disadvantage-subjective& lead to over adjustment/modification
  44. 44. Indicator paste • Pressure areas on intaglio surface& not used for border evaluations • Low viscosity &displaced by functional movements • Disadv-cannot built appreciable thickness without distortion so, not used for under extension
  45. 45. Disclosing waxes • Exhibit higher viscosities than indicator paste , it can with stand greater loads without complete displacement so, they built up to thickness • Modification with silicone gels/petrolatum
  46. 46. TECHNIQUE
  47. 47. CONCLUSION
  48. 48.
  49. 49. Thank you For more details please visit