maxillary anatomical landmarks

maxillary anatomical landmarks

1. BY - DR. AKANKSHA NARELA PG 1 ST YEAR Maxillary Anatomical landmarks

2. Introduction Intraoral landmarks Maxillary Arch Histology Supporting areas Peripheral/limiting areas Conclusion References

3. 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. This knowledge aids in determining - The selective placement of forces by the denture bases upon the supporting tissues. The form of the denture borders that will be harmonious with the normal function of the limiting structures that surround them.

5. INTRAORAL LANDMARKS

6. According to 9 th edition of Boucher & 12 th edition of Zarb & Bolender MAXILLARY ARCH STRESS BEARING AREA RELIEF AREA PRIMARY: RESIDUAL RIDGE SECONDARY: RUGAE INCISIVE PAPILLA, MEDIAN PALATAL RAPHE, FOVEA PALATINI.

7. ACCORDING TO BOUCHER’s 13 EDITION MAXILLARY ARCH STRESS BEARING AREA RELIEF AREA PRIMARY: FIRM TUBEROSITY, HARD PALATE ON EITHER SIDEOF PALATAL RAPHE SECONDARY: RUGAE, ALVEOLAR RIDGE PALATAL TORUS, MEDIAN PALATAL RAPHE ,FOVEA PALATINI .

8. Areas which are able to resist the vertical forces of occlusion.

9. Areas that resist the lateral forces of occlusion and can aid the resistance to the vertical forces.

10. That portion of the denture which is relieved to eliminate excessive pressure on specific parts of the denture supporting tissues.

11. Alveolar ridge (Residual ridge) Hard palate Incisive papilla Palatal rugae Median raphe Maxillary tuberosity Fovea palatinae

12. Labial frenum Labial sulcus Buccal frenum Buccal sulcus Distobuccal space Hamular notch Posterior palatal seal area

13. Correlation of anatomical landmarks - No . Landmark on mouth Landmark in impression 1 Labial frenum Labial notch 2 Labial vestibule Labial flange 3 Buccal frenum Buccal notch 4 Buccal vestibule Buccal flange 5 Coronoid bulge Coronoid contour 6 Residual alveolar ridge Alveolar groove 7 Maxillary tuberosity Maxillary tubercular fossa 8 Hamular notch Pterigomaxillary seal 9 Posterior palatal seal region Posterior palatal seal 10 Foveae palatinae Foveae palatinae 11 Median palatine raphae Median palatine groove 12 Incisive papilla Incisive fossa 13 Rugae region rugae 14 Displacable soft & hard palate Butterfly outline of pps

14. Mucosa - Submucosa - Formed by stratified squamous epithelium and a subjacent narrow layer of connective tissue is present called as lamina propria. Composed of connective tissue that varies from dense to loose areolar tissue. In edentulous people – mucosa covering hard palate + crest of residual ridge + residual attached gingiva = Masticatory Mucosa. Thickness varies and may contain glandular, fat or muscle cells and transmits the blood and nerve supply to the mucosa. Characterized by well define d keratinized layer on the outermost surface. Attachment occurs between submucosa and periosteal covering of the bone and it makes the bulk of the mucous membrane.

15. Oral Mucous Membrane Mucous Membrane -

16. The residual ridge is the remnant of the alveolar process which originally contained sockets for natural teeth. After natural teeth are extracted, the alveolar ridge can be expected to get smaller ( resorb ). The rate of resorption varies considerably from person to person.

17. Histology of the mucous membrane covering the crest of the residual ridge The submucosal layer is sufficiently thick to provide resiliency for support of complete denture The bone covering the crest of the upper ridge is often compact. Thus the crest is the primary stress bearing area. submucosa

18. The hard palate is made up of the anterior two-thirds of the palatal vault supported by bone (palatine processes of the maxillae and the horizontal plates of the palatine bones). The palatine process are joined together at the medial suture .

19. CONFIGURATION OF HARD PALATE :- Hard palate has been classified by various authors : Nichols - Tapering Square Arched /flat Heartwell , Elinger Shay - based on different slopes V- shaped Flat U-shaped High Medium

20. Gland tissue Adipose tissue Anterolateral part of the hard palate, with abundant adipose tissue Posterolateral part of the hard palate, with abundant gland tissue

21. It is a pad of fibrous connective tissue overlying the orifice of the nasopalatine canal. Significance : Stable landmark and gives its relation to incisive foramen through which the neurovascular bundle emerge and lie on the surface of bone.

22. 2. It is a biometric guide giving information on positional relation to central incisors which are about 8-10 mm anterior to incisive papilla. 3. Biometric guide which gives us information about location of maxillary canines (A perpendicular drawn posterior to the centre of incisive papilla to sagittal plane passes through canines).

23. Clinical Consideration : During final impression procedure, care should be taken not to compress the papilla. Hence the incisive papilla should be relieved with a spacer. Reason : a. Compression of blood vessels obliteration of the lumen  deprive nutrition to tissues  breakdown of tissues. b. Pressure on nerve causes parasthesia in the region of upper lip.

24. N. P. nerve and vessles Nassopalatine nerve and vessels in submucosa layer

25. They are raised areas of dense connective tissue radiating from the median suture in the anterior 1/3 rd of the palate. It is seconadary stress bearing area. Significance : Said to be concerned with phonetics. Increase the surface area of the foundation and thus supplement the values of retention. 3.It is the denture stabilizing area in the maxillary foundation.

26. It is the area extending from the incisive papilla to the distal end of the hard palate. Significance : Area of sutural joint and covered with firmly adherent mucous membrane to the underlying bone with little submucosal tissue. This sutural joint is formed by the median fusion of two maxillary processes and two horizontal plates of palatine bone.

27. 3. Function of sutural joint is growth and sometimes there will be overgrowth of the bone at the sutural joint resulting in torus palatinus . Clinical Considerations : During final impression procedure this raphe is relieved in order to create an equilibrium between the resilient and non resilient tissues.

28. Thin submucosa h/p of mid palatal suture showing thin submucosal layer

29. It is a narrow cleft of loose areolar tissue which is approximately 2mm in extent antero-posteriorly . It is situated between the distal surface of the tuberosity and the hamulus of medial pterygoid plate. Located by using T- burnisher . Significance : Constitutes the lateral boundary of posterior palatal seal area in maxillary foundation. The pterygomandibular raphe attaches to hamulus .

30. Clinical Consideration : Denture should not extend beyond the hamular notch, failure of which will result in : Restricted pterygomandibular raphe movement. When mouth is wide open the denture dislodges.

31. It is the distal most part of the residual alveolar ridge and presents the hard tissue landmarks. They are primary stress bearing area. Significance : The last posterior tooth should not be placed on the tuberosity . Clinical Significance : Often there is lateral and vertical growth of tuberosity and the area assumes importance when maxillary antrum extends laterally with undercuts at the tuberosity region.

32. It is important to prevent oro-antral fistula so it is important to have radiograph before resection of the tuberosity . It can be used for the retention of the denture.

33. They are the remnants of ducts of coalescence. Usually two in number on either side of the midline. They indicate the vicinity of posterior palatine seal area. Its position also influences the position of the posterior border of the denture. Denture can extend 1-2 mm across it. In patients with thick saliva, the fovea palatine should be left uncovered or else thick saliva flows between the tissue and increase the hydrostatic pressure and hence lead to denture displacement.

34. It appears as a fold of mucous membrane extending from the mucous lining of the lip to the crest of residual ridge on the labial surface. It may be single . It may be narrow / broad. It contains no muscle fibers of significance. It starts superiorly as a fan shape and converges as it descends to its terminal attachment on the labial side of the ridge.

35. Clinical Consideration : Sufficient relief should be given during final impression procedure and in completed prosthesis because overriding of function of frenum will cause pain and dislodgement of denture. During impression procedure the lip should be stretched horizontal outwards for the proper recording of frenum. If frenum is attached close to the crest frenectomy is done, failure of which will lead to the denture border being placed on the bone tissue which will cause decreased border seal.

36. It extends on both sides of the midline from labial frenum anteriorly to the buccal frenum posteriorly . It is bounded laterally by the labial mucosa, medially by maxillary residual alveolar ridge. It is lined by linig mucosa. Reflection of the mucous membrane superiorly reflects the height. The area of mucous membrane reflection has no muscle. Clinical Consideration : For effective border contact between denture and tissue, vestibule should be completely filled with impression material .

37. Fold or folds of mucous membrane extending from mucous membrane reflection area to the slope or crest of residual alveolar ridge. It forms the dividing line between the labial and the buccal vestibule. Significance : LEVATOR ANGULIORIS (CANINUS MUSCLE) lies beneath it and affect position of frenum . ORBICULARIS ORIS muscle pulls frenum forward. BUCCINATOR MUSCLE pulls frenum backword .

38. Clinical Consideration: During final impression procedure and in final prosthesis sufficient relief should be given for the movement of frenum because over-riding of function of frenum will cause pain and dislodgement of denture. During impression procedure the cheek should be reflected laterally and posteriorly . If frenum is attached close to the crest of alveolar ridge, frenectomy is called for.

39. Boundaries : It is bounded anteriorly by the buccal frenum, laterally by the buccal mucosa and medially by residual alveolar ridge. Size of vestibule varies with contraction of BUCCINATOR MUSCLE, POSITION OF MANDIBLE , AND AMOUNT OF BONE LOSS FROM MAXILLA.

40. Clinical Consideration : During impression procedure the vestibule should be completely filled with impression material for proper border contact between denture and tissues. When the vestibular space that is distal and lateral to the alveolar tubercles is properly filled with denture flange the stability and retention of the maxillary denture is greatly enhanced.

41. 3.The buccal flange borders depend upon movement of ramus of mandible at the distal end of buccal vestibule and hence the patient should move the mandible laterally and protrusively to make sure the mandible does not interfere with these functions. 4.To effectively record the maxillary buccal sulcus the mouth should be half way closed because wide opening of the mouth narrows the space and does not allow proper contouring of sulcus because the coronoid process of mandible comes closer to the sulcus.

42. D istobuccal space N. S. Arbree , D.D.S.,* A. A. Yurkstas , D.M.D., M.S.,** and J. H. Kronman , D.D.S., Ph.D.*** Tufts University, School of Dental Medicine, Boston, Mass Also known as Buccal space or vestibule, Buccal pocket, Tuberosity sulcus , Distobuccal angle of the buccal vestibule, Buccal sulcus Buccal pouch, Buccal mucous membrane reflection region Postmalar area

43. The coronomaxillary space: Literature review and anatomic description The coronomaxillary space is that anatomic region that lies medial to the coronoid process and lateral to the maxillary tuberosity . It is bounded anteriorly -by the base of the zygomatic process. posterior boundary- pterygomaxillary or hamular notch inferior boundary - crest of the residual ridge. The coronomaxillary flange of the maxillary denture is that portion of the buccal flange that extends from the zygomatic eminence to the hamular notch

44. Muscular influence Muscles affecting distobuccal space interaction b/w buccinator & masseter Superior constrictor of pharynx Medial pterygoid muscle , temporalis muscle Pterygomandibular raphae

45. The coronoid process may be relatively straight or vertical in some individuals . For these patients opening of the mandible can result in narrowing of the space. In some individuals, however, the coronoid process appears to flare laterally at its height With a stronger temporal muscle insertion, this flare can be increased. If the individual with a lateral flare of the coronoid process is observed during opening, the space often remains the same or becomes wider.

46. Various studies demonstrates alteration in coronomaxillary space on wide opening of mouth, and some says no change in opening. If the coronomaxillary space broadens or remains the same size on opening , the functional filling of this space with the denture flange becomes important.” If the space is not completely filled or even slightly overfilled,‘,’ maximum retention may be lost. In this instance it is advisable not to have the patient open wide, protrude, or move laterally during border molding or impression procedures.“,’ A gentle molding of the region by pulling the cheek out, down, and in will be more successful

47. It is also called as Post dam, Post palatal seal . Defined as – The soft tissue area at or beyond the junction of the hard and soft palates on which pressure, within physiologic limits, can be applied by a denture to aid in its retention . (GPT -7) Hardy and Kapur stated that retention and stability that is achieved from adhesion ,cohesion and interfacial surface tension are able to resist those dislodging forces that are perpendicular to the denture base. Horizontal and lateral torquing of the maxillary denture can be resisted only by adequate border seal.

48. Boundaries of posterior palatal seal area – Anteriorly – Anterior vibrating line Posteriorly - Posterior vibrating line Laterally – Pterygomaxillary notch

49. Anterior Vibrating line – An imaginary line located at the junction of the attached tissues overlying the hard palate and the movable tissues of the immediately adjacent hard palate. Shape – bow shaped anteriorly , sometimes referred to as “Cupid’s Bow”. Located by – Valsalva Maneuver - Both the nostrils are held firmly while the patient blows gently through the nose. This positions the soft palate downwards at its junction with the hard palate. Patient is asked to say “ah” with short vigorous bursts. .

50. Posterior vibrating line – An imaginary line at the junction of the aponeurosis of the tensor veli palatini and the muscular portion of the soft palate. Located by - it can be visualised when the patient says “ah” in a normal un exaggerated fashion

51. Significance : 1) It maintains contact of denture with soft tissue during functional movements of stomatognathic system (mastication, deglutition and phonation etc.) 2) Decreases gag reflex. 3) Decreases food accumulation with adequate tissue compressibility. 4) Decrease patient discomfort of tongue with posterior part of denture

52. 5) Compensation of volumetric shrinkage that occurs during the polymerization of PMMA. 6) Permits normal movement of muscles and ligaments. 7) Increases retention and stability by creating a partial vacuum. 8) Increased strength of maxillary denture base.

53. Classification of PPS based on soft palate configuration (BERNARD LEVIN)- Class I:- Greater than 5 mm of movable tissue available for post damming. It is the ideal for retention. Usually thin denture base is advisable. Class II: - 1-5 mm of movable tissue available for post damming, good retention is usually possible. A medium thickness of denture base is quite adequate.

54. FACTORS INFLUENCING PPS The accuracy of PPS reproduction in complete denture depends on various factors :- Configuration of hard palate. Investing medium Factors involved in processing of acrylic resin. Denture base thickness. Head position

55. PPS determination methods can be broadly categorized based on stage of denture construction as follows: PPS determination in final impression stage. PPS determination or designing on master cast. Recording PPS in Secondary Impression Appointment Stage Methods to record pps

56. Determining PPS on Master Cast Boucher's Technique Bernard Levin's Technique Swenson's Technique Calomeni , Feldman,Kuebker's Technique Pound's Technique Apple Baum Winkler's Technique Silverman's Technique Hardy and Kapur Technique

57. The basic goal of a successful complete denture therapy is reaching the patients expectations in fulfillment of better masticatory ability, unaltered speech and a better esthetics. Extensions of the borders to get a good seal facilitates the clinician to obtain the compromised treatment approach. The clinician should have the anatomical knowledge to fabricate prosthesis which inturn aids in proper maintenance of stomatognathic system.

58. The knowledge of oral anatomy, microscopic as well as macroscopic better equips us as prosthodontists to - Decide how to make the impression. What material to use? How to plan the treatment? All this will result in a successful prosthetic treatment

59. 1. Zarb,Bolender,Carlson – Boucher’s prosthodontic treatment for edentulous patients,12 th edition 2. Sharry J.J. – Complete denture prosthodontics;ed.3.New York , 1974 3.Heartwell Charles – syllabus for complete dentures Ed.4,Philadelphia 4 . Sheldon Winkler – Essentials of complete denture Prosthodontics,ed.2 5 . O Boucher – Swenson’s complete denture Prosthodontics,ed.6 References -

60. 11.Benard Lynn,Detriot,Mich – Significance of anatomic landmarks in complete denture service,JPD,1964,14:456-459 12.H.R.Kolb-Variable denture limiting structures of the edentulous mouth,Part 1 ,maxillary border areas,JPD 1966,16:194-204 13.Colie H Millsap-The posterior palatal seal area for complete denture. DCNA,Nov.1964,663 14’.Nallaswamy-Textbook of prosthodontics,ed . 1 15.Inderbir Singh-Textbook of human histology with colour atlas,ed.3 17.Orban-Oral histology & embryology,ed.10 16.Elinger-synopsis of complete denture prosthodontics,ed.1 18.N. S. Arbree , D.D.S.,* A. A. Yurkstas , D.M.D., M.S.,** and J. H. Kronman , D.D.S., Ph.D.***Tufts University, School of Dental Medicine, Boston, Mass