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ANATOMY AND CLINICAL
SIGNIFICANCE OF DENTURE
BEARING AREAS
GROUP 3
DEN/2012/004……….. Chairman
DEN/2012/001……….. Secretar...
OUTLINE
INTRODUCTION
ANATOMY OF DENTURE BEARING
AREAS
CLINICAL SIGNIFICANCE OF
DENTURE BEARING AREAS
CONCLUSION
REFER...
INTRODUCTION
M.M Devan Dictum “Aim of a prosthodontist is not only the
meticulous replacement of what is missing, but als...
ANATOMY OF DENTURE BEARING
AREAS
The anatomy of edentulous ridges in the maxilla and
mandible is very important for the d...
THE ORAL MUCOUS MEMBRANE
Serves as a cushion between the denture base and the
supporting bone.
Mucous membrane is compos...
ORAL MUCOUS MEMBRANE
ANATOMY OF DENTURE
BEARING AREA - MAXILLA
The ultimate support for the maxillary denture are the bones
of the two maxilla...
LIMITING STRUCTURES OF THE
MAXILLA
 Limiting structures are sites that will guide us in having an
optimum extension of de...
LABIAL FRENUM
 Single or double fibrous band covered
by mucous membrane which extends
from labial aspect of residual alve...
LABIAL VESTIBULE
 It extends from buccal frenum on one side to
the other, being divided into right and left by
labial fre...
BUCCAL FRENUM
 Band of fibrous tissue overlying the levator
anguli oris, that divides labial vestibule from
buccal vestib...
BUCCAL VESTIBULE
 Buccal vestibule extends from the buccal
frenum to the hamular notch.
 Bounded externally by cheeks an...
HAMULAR NOTCH
 Hamular notch forms the distal limit of the
buccal vestibule, located between the tuberosity
and the hamul...
POSTERIOR PALATAL SEAL AREA
 Also known as post dam.
 “The soft tissues at or along the
junction of the hard and soft
pa...
POSTERIOR PALATAL SEAL AREA
PARTS
 postpalatal seal
 pterygomaxillary seal
EXTENSIONS
 anteriorly- anterior vibrating l...
Pterygomaxillary seal Postpalatal seal
DIFFERENCES
 It is the part of the
posterior palatal seal that
extends across the
...
Pterygomaxillary seal Postpalatal seal
POSTERIOR PALATAL SEAL AREA
VIBRATING LINE
 “The imaginary line across the posterior part of the palate marking
the division between the movable and ...
ANTERIOR VIBRATING LINE
 It is an imaginary line lying at the
junction between the immovable
tissue over the hard palate ...
POSTERIOR VIBRATING LINE
 It is an imaginary line located at the junction of the soft palate that
shows limited movement ...
POSTERIOR PALATAL SEAL CONTD
CLINICAL SIGNIFICANCE:
 It maintains contact with the anterior portion of the soft palate du...
FOVEA PALATINAE
 These are the depresssions or indentations situated on
the soft palate on the either side of the midline...
SUPPORTING STRUCTURES OF
MAXILLA
PRIMARY STRESS BEARING
 HARD PALATE
 POSTERO-LATERAL SLOPES OF THE RESIDUAL
ALVEOLAR RI...
HARD PALATE
 It is formed by palatine shelves of
the maxillary bone and the
premaxilla.
 Lined by keratinised epithelium...
POSTERO-LATERAL SLOPES OF
THE RESIDUAL ALVEOLAR RIDGE
 “The portion of the alveolar ridge and its soft
tissue covering wh...
RUGAE
 These are the mucosal folds located in the anterior
region of the palatal mucosa.
 In the area of rugae, the pala...
MAXILLARY TUBEROSITY
 It is the bulbous extension of the
residual alveolar ridge in the 2nd
and 3rd molar region, termina...
NOTE
 Residual ridge was first considered to be a primary stress bearing
area but it is now considered a secondary stress...
RELIEF AREAS
These are areas in the denture bearing areas which should be
relived during construction of dentures.
Incisi...
INCISIVE PAPPILAE
 It is the midline structure situated behind the
central incisors.
 Incisive foramen lies immediately ...
MID-PALATINE RAPHE
 This is the median suture area covered
by a thin sub-mucosa, so the mucosa
layer is in close contact ...
FOVEA PALATINE
 Bilateral indentations near the midline of
palate. Posterior to junction of hard and soft
palate
 These ...
PALATINE TORUS
 A developmental bony prominence
sometimes seen in the centre of the
palate. This structure is often cover...
RUGAE
 Irregular shaped ridges of the
connective tissue covered by
mucous membrane in the anterior
third of the hard pala...
ANATOMY OF DENTURE BEARING
AREAS- MANDIBLE
 These are areas in mandible that are closely related to the base of
the mandi...
ANATOMICAL LANDMARKS OF
EDENTULOUS MANDIBLE
LIMITING STRUCTURES OF THE
MANDIBLE
LABIAL FRENUM
LABIAL VESTIBULE
BUCCAL FRENUM
BUCCAL VESTIBULE
LINGUAL FRENUM
ALV...
LABIAL FRENUM
 It is a fold of mucous membrane at the
median line. It divides the labial vestibule into
left and right la...
LABIAL VESTIBULE
 It runs from the buccal frenum to buccal
frenum. It is divided into left and right by
labial frenum.
 ...
BUCCAL FRENUM
 The buccal frenum forms the dividing
line between the labial and buccal
vestibule.
 May be single or doub...
BUCCAL VESTIBULE
 Extends from buccal frenum to retromolar pad.
 It is nearly at right angles to biting forces.
 Extent...
LINGUAL FRENUM
 It is a fold of mucous membrane existing when
the tip of the tongue is elevated.
 It overlies the geniog...
ALVEOLOLINGUAL SULCUS
 It is the space between residual ridge and tongue.
 Extends from lingual frenum to rectomylohyoid...
ALVEOLOLINGUAL SULCUS-
RETROMYLOHYOID SPACE
 The retromylohyoid space lies at
distal end of the alveololingual
sulcus
 I...
ALVEOLOLINGUAL SULCUS-
RETROMYLOHYOID CURTAIN
 Formed posteriorly by the
superior constrictor muscle,
laterally by the ma...
RETROMOLAR PAD
 It is a non-keratinised triangular pear-shaped pad
of tissue at the distal end of the lower ridge.
 Subm...
PTERYGOMANDIBULAR RAPHE
 Raphe is a tendinous insertion of two
muscles.
 Arises from the hamular process of the
medial p...
SUPPORTING STRUCTURES OF THE
MANDIBLE
These are areas responsible for bearing loads in the
mandible.
Buccal shelf area
...
BUCCAL SHELF AREA
 It is the area between buccal frenum and anterior
border of masseter muscle.
 BOUNDARIES:
 Medially-...
BUCCAL SHELF AREA
RESIDUAL ALVEOLAR RIDGE
 The edentulous mandible may become flat, due to resorption;
which results into outward inclinati...
RELIEF AREA
Mental foramen
Genial tubercle
Mylohyoid ridge
Mandibular tori
MENTAL FORAMEN
 It lies between the 1st and 2nd
premolar region.
 Due to ridge resorption, it may lie
close to the ridge...
GENIAL TUBERCLE
 The genial tubercle are a pair of dense
prominences at the inferior border of the
mandible at the lingua...
MYLOHYOID RIDGE
 The mylohyoid ridge is a bony
prominence along the lingual aspect of
the mandible
 Soft tissue usually ...
MANDIBULAR TORI
 These are the abnormal bony
prominence found bilaterally on the
lingual side, near the premolar region
b...
CONCLUSION
 Thus, we see that a sound knowledge of the
anatomical landmarks of the denture bearing area is a
prerequisite...
REFERENCES
 Prosthodontic treatment for edentulous patient : Zarb
Bolender
 Preclinical manual of prosthodontics : S Lak...
Anatomy and clinical significance of denture bearing areas
Anatomy and clinical significance of denture bearing areas
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Anatomy and clinical significance of denture bearing areas

A presentation on the anatomy and clinical significance of the denture bearing areas by Ogundiran Temidayo who is a dental student at OBAFEMI AWOLOWO UNIVERSITY ILE-IFE

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Anatomy and clinical significance of denture bearing areas

  1. 1. ANATOMY AND CLINICAL SIGNIFICANCE OF DENTURE BEARING AREAS GROUP 3 DEN/2012/004……….. Chairman DEN/2012/001……….. Secretary DEN/2012/003 DEN/2012/024 DEN/2011/015 DEN/2012/019
  2. 2. OUTLINE INTRODUCTION ANATOMY OF DENTURE BEARING AREAS CLINICAL SIGNIFICANCE OF DENTURE BEARING AREAS CONCLUSION REFERENCES
  3. 3. INTRODUCTION M.M Devan Dictum “Aim of a prosthodontist is not only the meticulous replacement of what is missing, but also perpetual preservation of what is present” A prosthesis must function in harmony with the tissues that support them and those that surround them. Hence the dentist must understand the macroscopic as well as microscopic anatomy of the supporting and limiting structures of the denture.
  4. 4. ANATOMY OF DENTURE BEARING AREAS The anatomy of edentulous ridges in the maxilla and mandible is very important for the design of the complete denture. The total area of support from the mandible is significantly less than from the maxilla. The average available denture bearing area for an edentulous mandible is 14cm2,whereas for edentulous maxilla it is 24cm2. Therefore the mandible is less capable of resisting occlusal forces than the maxilla.
  5. 5. THE ORAL MUCOUS MEMBRANE Serves as a cushion between the denture base and the supporting bone. Mucous membrane is composed of mucosa and sub mucosa. Sub-mucosa is formed by connective tissue that varies from dense to loose areolar tissue. Mucosa covering the hard palate and the crest of the ridge is classified as MASTICATORY MUCOSA. The mucosa is characterized by its well defined KERATINIZED EPITHELIUM.
  6. 6. ORAL MUCOUS MEMBRANE
  7. 7. ANATOMY OF DENTURE BEARING AREA - MAXILLA The ultimate support for the maxillary denture are the bones of the two maxilla and the palatine bone. The anatomical land marks in the maxilla are LIMITING STRUCTURES SUPPORTING STRUCTURES RELIEF AREAS
  8. 8. LIMITING STRUCTURES OF THE MAXILLA  Limiting structures are sites that will guide us in having an optimum extension of denture so as to engage maximum surface area without encroaching upon the muscle action.  These are structures that limit the extent of the denture: 1. Labial frenum 2. Labial vestibule 3. Buccal frenum 4. Buccal vestibule 5. Hamular notch 6. Posterior palatal seal 7. Fovea palatinae
  9. 9. LABIAL FRENUM  Single or double fibrous band covered by mucous membrane which extends from labial aspect of residual alveolar ridge to the lip.  Absence of muscle fibers. CLINICAL SIGNIFICANCE  Limits labial flange of denture.  It has to be relieved while making impression in other to prevent dislodgement of the denture and to prevent ulceration. It is seen as a V- shaped notch in the impression.
  10. 10. LABIAL VESTIBULE  It extends from buccal frenum on one side to the other, being divided into right and left by labial frenum.  Anteriorly: orbicularis oris muscle  Posteriorly: labial aspect of alveolar ridge. It has a thin mucosa and thick submucosa with large amount of loose areolar tissue and elastic fibers. CLINICAL SIGNIFICANCE  The labial flange of the denture will be in complete contact with labial vestibule to provide a peripheral seal in the denture.
  11. 11. BUCCAL FRENUM  Band of fibrous tissue overlying the levator anguli oris, that divides labial vestibule from buccal vestibule.  The orbicularis oris pulls frenum forward and the buccinator pulls it backward. CLINICAL SIGNIFICANCE  Since it has muscular attachments, adequate relief must be provided to prevent the dislodgment of denture.(that is, it can move posteriorly as a result of the buccinator muscle and anteriorly as a result of the orbicularis oris.)  It requires more clearance for its action than labial frenum because it moves mesially, buccally and vertically by orbicularis oris, buccinator and levator anguli oris respectively.
  12. 12. BUCCAL VESTIBULE  Buccal vestibule extends from the buccal frenum to the hamular notch.  Bounded externally by cheeks and internally by residual alveolar ridge.  The size of the vestibule varies with the contraction of the buccinator muscle. CLINICAL SIGNIFICANCE  The patient’s mouth must be half open during impression taking, because opening of mouth during final impression causes the coronoid process to move anteriorly narrowing the buccal vestibule.  Compared to labial flange, buccal flange has less interference and so provides maximum retention.
  13. 13. HAMULAR NOTCH  Hamular notch forms the distal limit of the buccal vestibule, located between the tuberosity and the hamulus of the medial pterygoid plate.  Pterygomandibular raphe is attached to the hamular notch.  It has thick submucosa made up of loose areolar tissue. CLINICAL SIGNIFICANCE  If denture border is short of the hamular notch The denture will not have a posterior seal resulting in loss of retention of the denture.  If denture extend beyond hamular notch The pterygomandibular raphe is pulled forward when patient opens mouth causing dislodgement of denture.
  14. 14. POSTERIOR PALATAL SEAL AREA  Also known as post dam.  “The soft tissues at or along the junction of the hard and soft palate on which pressure along the physiological limits of the tissues can be applied by the the denture to aid in the retention of the denture.”-GPT (GLOSSARY OF PROSTHODONTICS TERM)
  15. 15. POSTERIOR PALATAL SEAL AREA PARTS  postpalatal seal  pterygomaxillary seal EXTENSIONS  anteriorly- anterior vibrating line  posteriorly- posterior vibrating line  laterally- 3-4mm anterior-lateral to hamular notch
  16. 16. Pterygomaxillary seal Postpalatal seal DIFFERENCES  It is the part of the posterior palatal seal that extends across the hamular notch and extends 3 to 4 mm anterolaterally to end in the mucogingival junction on the posterior part of the maxillary ridge.  It is the part of the posterior palatal seal area that extends between the two maxillary tuberosities.
  17. 17. Pterygomaxillary seal Postpalatal seal POSTERIOR PALATAL SEAL AREA
  18. 18. VIBRATING LINE  “The imaginary line across the posterior part of the palate marking the division between the movable and immovable tissues of the soft palate which can be identified when the movable tissue is moving’’-GPT  Denture should extend 1-2mm posterior to this vibrating lines. Types:  Anterior vibrating line  Posterior vibrating line
  19. 19. ANTERIOR VIBRATING LINE  It is an imaginary line lying at the junction between the immovable tissue over the hard palate and the slightly movable tissues of the soft palate.  It is cupid bow shaped(because of the shape of the underlying bone).  Valsalva maneuver: The patient is asked to close his nostrils firmly and gently blow through his nose, to locate the anterior vibrating line. Arrow showing the bone that gives bow shape to anterior vibrating line in edentulous patients.
  20. 20. POSTERIOR VIBRATING LINE  It is an imaginary line located at the junction of the soft palate that shows limited movement and the soft palate that shows marked movement.  This line is usually straight.
  21. 21. POSTERIOR PALATAL SEAL CONTD CLINICAL SIGNIFICANCE:  It maintains contact with the anterior portion of the soft palate during functional movements of the stomatognatic system (i.e mastication, deglutition and phonation). Therefore, the primary purpose of the posterior palatal seal is the retention of maxillary denture.  Reduces the tendency for gag reflex as it prevents the formation of the gap between the denture base and the soft palate during functional movements.  Prevents food accumulation between the posterior border of the denture and the soft palate.
  22. 22. FOVEA PALATINAE  These are the depresssions or indentations situated on the soft palate on the either side of the midline.  It is formed by coalescence of the duct of several mucous glands.  The position of the fovea palatinae also influences the posterior border of the denture.  The secretion of the fovea spreads as a thin film on the denture therefore aiding in retention. CLINICAL SIGNIFICANCE  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.
  23. 23. SUPPORTING STRUCTURES OF MAXILLA PRIMARY STRESS BEARING  HARD PALATE  POSTERO-LATERAL SLOPES OF THE RESIDUAL ALVEOLAR RIDGE SECONDARY STRESS BEARING AREA  RUGAE  MAXILLARY TUBEROSITY  ALVEOLAR TUBERCLE
  24. 24. HARD PALATE  It is formed by palatine shelves of the maxillary bone and the premaxilla.  Lined by keratinised epithelium.  The horizontal of the hard palate provides the PRIMARY STRESS- BEARING AREA. CLINICAL SIGNIFICANCE  The trabecular pattern in the bone is perpendicular to the direction of force, making it capable of withstanding any amount of force without marked resorption.
  25. 25. POSTERO-LATERAL SLOPES OF THE RESIDUAL ALVEOLAR RIDGE  “The portion of the alveolar ridge and its soft tissue covering which remains following removal of the teeth.”-GPT  Lined by thick stratified squamous epithelium.  Even though the sub-mucosa is thin it sufficiently provide adequate resiliency to support the denture.  It resorbs rapidly following extractions and continues throughout life at a reduced rate. CLINICAL SIGNIFICANCE  The vertical forces during physiological activities like mastication falls on denture and is transmitted posteriorly. The postero-lateral slopes of the ridge bears the force and hence is the primary supporting structure.
  26. 26. RUGAE  These are the mucosal folds located in the anterior region of the palatal mucosa.  In the area of rugae, the palate is set at an angle to the residual alveolar ridge and is thinly covered by soft tissue which contributes to the secondary stress bearing area. CLINICAL SIGNIFICANCE  It is associated with the sensation of taste and the function of speech.  They assist the tongue to absorb via its papillae.  They also enable the tongue to form a perfect seal when it is pressed against the palate in making linguo- palatal constant stops of speech.  Rugae should not be displaced, otherwise the rebounding may dislodge the denture.  They provide antero-posterior resistance to movement of the denture and increased surface surface area helps in retention.
  27. 27. MAXILLARY TUBEROSITY  It is the bulbous extension of the residual alveolar ridge in the 2nd and 3rd molar region, terminating in the hamular notch. CLINICAL SIGNIFICANCE  The area is less likely to resorb.  Artficial teeth are not set on tuberosity region.  The tuberosities sometimes exhibit buccal undercuts, if it is unilateral it can be utilized for the retention.
  28. 28. NOTE  Residual ridge was first considered to be a primary stress bearing area but it is now considered a secondary stress bearing area because of the fact that bone is subjected to continuous resorption though it decreases as the span of edentulism increases.
  29. 29. RELIEF AREAS These are areas in the denture bearing areas which should be relived during construction of dentures. Incisive papillae Mid-palatine raphe Fovea palatine Palatine torus Rugae
  30. 30. INCISIVE PAPPILAE  It is the midline structure situated behind the central incisors.  Incisive foramen lies immediately beneath the papillae.  As resorption progresses, it comes to lie nearer to the crest of the ridge.  The naso-palatine nerves and vessels pass through it. CLINICAL SIGNIFICANCE  While making final impression pressure should not be applied on this region.
  31. 31. MID-PALATINE RAPHE  This is the median suture area covered by a thin sub-mucosa, so the mucosa layer is in close contact with the underlying bone  For this region, the soft tissue covering the median palatal tissue is non- resilient in nature and may need to be relieved. CLINICAL SIGNIFICANCE  If pressure is applied during impression making,the denture base will cause soreness over the midpalatine raphe area.
  32. 32. FOVEA PALATINE  Bilateral indentations near the midline of palate. Posterior to junction of hard and soft palate  These are a pair of mucous gland duct orifice near the midline at the junction of the hard and the soft palate  Formed by coalescence of several mucous gland duct CLINICAL SIGNIFICANCE  Aids in determining vibrating line  These landmarks provide a guide to the position of the posterior palatal border of a denture
  33. 33. PALATINE TORUS  A developmental bony prominence sometimes seen in the centre of the palate. This structure is often covered by relatively incompressible mucoperiosteum CLINICAL SIGNIFICANCE  If it is small, the denture is relieved  A mucosally supported denture may need to be relieved over the torus to prevent the denture rocking and flexing about the mid line.
  34. 34. RUGAE  Irregular shaped ridges of the connective tissue covered by mucous membrane in the anterior third of the hard palate CLINICAL SIGNIFICANCE  Should not be disturbed by impression for maximum comfort
  35. 35. ANATOMY OF DENTURE BEARING AREAS- MANDIBLE  These are areas in mandible that are closely related to the base of the mandibular complete denture. They are covered with mucosa and sub mucosa of varying degree of thickness and compressiblity.  The anatomical landmarks in the mandible are ; LIMITING STRUCTURES SUPPORTING STRUCTURES RELIEF AREAS
  36. 36. ANATOMICAL LANDMARKS OF EDENTULOUS MANDIBLE
  37. 37. LIMITING STRUCTURES OF THE MANDIBLE LABIAL FRENUM LABIAL VESTIBULE BUCCAL FRENUM BUCCAL VESTIBULE LINGUAL FRENUM ALVEOLOLINGUAL SULCUS RETROMOLAR PAD PTERYGOMANDIBULAR RAPHE
  38. 38. LABIAL FRENUM  It is a fold of mucous membrane at the median line. It divides the labial vestibule into left and right labial vestibule.  It consist of band of fibrous connective tissue and helps to attach orbicularis oris muscle.  It is shorter and wider than the maxillary labial frenum. CLINICAL SIGNIFICANCE  During final impression, making sufficient relief must be given without compromising the peripheral seal.  The frenum is quite sensitive and active, and the denture must be fitted carefully around it to maintain a seal without causing soreness.
  39. 39. LABIAL VESTIBULE  It runs from the buccal frenum to buccal frenum. It is divided into left and right by labial frenum.  Fibers of orbicularis oris,incisivus and mentalis are inserted near the crest of the ridge. Mentalis muscle is an active muscle. CLINICAL SIGNIFICANCE  Extent of the denture flange in this region is often limited because of muscle that are inserted close to the crest of the ridge.  Thick denture flanges may cause dislodgement of dentures when patient opens the mouth wide open.
  40. 40. BUCCAL FRENUM  The buccal frenum forms the dividing line between the labial and buccal vestibule.  May be single or double, broad U shaped or sharp V shaped.  It overlies depressor anguli oris muscle.  Fibres of the buccinator muscle attach to the frenum. CLINICAL SIGNIFICANCE  Relief for buccal frenum is given in denture to avoid displacement of the denture.
  41. 41. BUCCAL VESTIBULE  Extends from buccal frenum to retromolar pad.  It is nearly at right angles to biting forces.  Extent of the buccal vestibule is influenced by buccinators muscle,which extends from modiolous anteriorly to pterygomandibular raphe.  The masseter muscle contracts under heavy closing force and pushes inward against the buccinators muscle to produce a massetric notch in the distobuccal border of the lower denture. CLINICAL SIGNIFICANCE  The distobuccal border of the lower denture should accommodate the contracting masseter muscle so that the denture does not dislodge during heavy closing force.
  42. 42. LINGUAL FRENUM  It is a fold of mucous membrane existing when the tip of the tongue is elevated.  It overlies the genioglossus muscle which takes origin from the superior genial tubercle.  The anterior region of the lingual flange is called sub-lingual crescent area. CLINICAL SIGNIFICANCE  The relief for the lingual frenum should be registered during function.  A short frenum is called tongue tie. It should be corrected if it affects the stability of the denture.
  43. 43. ALVEOLOLINGUAL SULCUS  It is the space between residual ridge and tongue.  Extends from lingual frenum to rectomylohyoid curtain  It has 3 regions (anterior, middle and posterior)  The anterior region extends from the lingual frenum back to where mylohyoid muscle curves above the level of the sulcus (premylohyoid fossa)  The middle region extends from premylohyoid fossa to the distal end of the mylohyoid ridge, curving medially from the body of mandible. The curvature is caused by the prominence of mylohyoid ridge and the action mylohyoid muscle  The posterior region: here, the flange passes into the rectomylohyoid fossa and completes the TYPICAL S FORM of the correctly shaped lingual flange CLINICAL SIGNIFICANCE The lingual flange of the lower denture will be short anteriorly than posteriorly The lingual flange in the middle region slopes medially towards the tongue
  44. 44. ALVEOLOLINGUAL SULCUS- RETROMYLOHYOID SPACE  The retromylohyoid space lies at distal end of the alveololingual sulcus  It is bounded by anterior tonsillar pillar, posteriorly by the retromylohyoid curtain
  45. 45. ALVEOLOLINGUAL SULCUS- RETROMYLOHYOID CURTAIN  Formed posteriorly by the superior constrictor muscle, laterally by the mandible and pterygo-mandibular raphe, anteriorly by lingual tuberosity, and inferioirly by the mylohyoid muscle  NOTE: RMC IS RETROMYLOHYOID CURTAIN
  46. 46. RETROMOLAR PAD  It is a non-keratinised triangular pear-shaped pad of tissue at the distal end of the lower ridge.  Submucosa contains glandular tissue, fibers of buccinators and superior constrictor muscle, pterygomandibular raphe and terminal part of the tendon of the temporalis.  The retromolar papilla is a pear shaped area just anterior to the retromolar pad, it is a dense fibrous connective tissue. CLINICAL SIGNIFICANCE  The distal end of the denture pad should cover 2/3rd of the retromolar pad.  The retromolar pad provides the peripheral posterior seal for the lower denture.
  47. 47. PTERYGOMANDIBULAR RAPHE  Raphe is a tendinous insertion of two muscles.  Arises from the hamular process of the medial pterygoid and gets attached to the mylohyoid ridge.  Muscular attachments present here are:  superior constrictor: postreolaterally  Buccinator: anterolaterally CLINICAL SIGNIFICANCE  Since it is very prominent in some patients, a notch like relief must be provided on the denture.
  48. 48. SUPPORTING STRUCTURES OF THE MANDIBLE These are areas responsible for bearing loads in the mandible. Buccal shelf area Residual alveolar ridge
  49. 49. BUCCAL SHELF AREA  It is the area between buccal frenum and anterior border of masseter muscle.  BOUNDARIES:  Medially-the crest of the ridge.  Distally-the retromolar pad  Laterally-the external oblique ridge.  The mucous membrane covering the buccal shelf area is loosely attached, less keratinized and contains a thick submucosa overlying a cortical plate. CLINICAL SIGNIFICANCE  It lies at right angles to the vertical occlusal force; this makes it suitable as primary stress bearing area for lower denture.
  50. 50. BUCCAL SHELF AREA
  51. 51. RESIDUAL ALVEOLAR RIDGE  The edentulous mandible may become flat, due to resorption; which results into outward inclination and progressively widening of mandible.  Similarly maxilla resorbs upward and inward making it smaller.  It is the reason for edentulous patients to have prognathic apperance  The slopes of residual alveolar ridge have thin plate of cortical bone. The slopes of the ridge are at an acute angle to occlusal forces.  Hence, it is considered as a SECONDARY stress bearing area.  Since crest of the ridge has cancellous bone, it is not favourable as primary stress bearing area. CLINICAL SIGNIFICANCE.  Any movable soft tissue overlying the ridge should not be compressed while making impression.
  52. 52. RELIEF AREA Mental foramen Genial tubercle Mylohyoid ridge Mandibular tori
  53. 53. MENTAL FORAMEN  It lies between the 1st and 2nd premolar region.  Due to ridge resorption, it may lie close to the ridge. CLINICAL SIGNIFICANCE  It should be relieved in these areas as pressure over the nerve passing through it can get compressed by denture base leading to paraesthesia (numbness) of lower lip.
  54. 54. GENIAL TUBERCLE  The genial tubercle are a pair of dense prominences at the inferior border of the mandible at the lingual midline  They represents the muscle attachment of the genioglossus and geniohyoid muscle. CLINICAL SIGNIFICANCE  They only become relevant in the denture when there is excessive resorption of the residual ridge.
  55. 55. MYLOHYOID RIDGE  The mylohyoid ridge is a bony prominence along the lingual aspect of the mandible  Soft tissue usually hides the sharpness of the mylohyoid ridge  Anteriorly, this ridge with mylohyoid muscle is close to the inferior surface of the mandible  Posteriorly, after resorption, it often flushes with the residual ridge. CLINICAL SIGNIFICANCE  The mucosa membrane overlying the sharp or irregular mylohyoid ridge needs to be relieved because denture base might easily traumatize it.
  56. 56. MANDIBULAR TORI  These are the abnormal bony prominence found bilaterally on the lingual side, near the premolar region but they may extend posteriorly to the molar area  It is covered by thin mucosa. CLINICAL SIGNIFICANCE  It has to be relieved or surgically removed, according to its size and extent.  Small tori may only require relief in the denture  Large tori requires removal before a denture can be fabricated.
  57. 57. CONCLUSION  Thus, we see that a sound knowledge of the anatomical landmarks of the denture bearing area is a prerequisite, if one has to achieve the objective one has in mind; fabrication of a complete denture that has maximum retention, stability and support with preservation of underlying structures with minimum post insertion problems.
  58. 58. REFERENCES  Prosthodontic treatment for edentulous patient : Zarb Bolender  Preclinical manual of prosthodontics : S Lakshmi  Impressions for complete dentures : Bernard Levin  Textbook of Prosthodontic : Nallasyamy  Boucher’s prosthodontics treatment for edentulous patients. 13th Edition  Heartwell’s syllabus of complete denture. 4th edition.

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A presentation on the anatomy and clinical significance of the denture bearing areas by Ogundiran Temidayo who is a dental student at OBAFEMI AWOLOWO UNIVERSITY ILE-IFE

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