02- Definitions� �(Occlusion in prosthodontics) �.pptx

02- Definitions� �(Occlusion in prosthodontics) �.pptx

1. 2. Definitions and terminologies Complete Denture Occlusion

2. Dr. Amal Fathy Kaddah Prof. of Prosthodontic, Faculty of Dentistry, Cairo University Definitions

3. Welcome to my page on Facebook Prof. Amal Kaddah Scientific Forum

4. The stomatognathic system. Definitions and terminologies . The significance of “ideal occlusion", What 'occlusion' is and why it is important Anatomy of the TMJ and basics of mandibular movements. Articulators in Dentistry. Facebows and Jaw tracking devices. Difference between natural and denture based artificial Occlusion. Determinant of occlusion in natural dentition. Basic of ideal occlusal contacts in natural teeth. Static and dynamic dental occlusion and occlusal adjustments in fixed restoration Types of artificial posterior teeth (Shapes, Indications and Problems) Factors affecting selection of tooth forms.andBalanced occlusion/Articulation for removable and fixed Prostheses: Definitions(Balanced occlusion/Articulation) Types of Balance as Related to Complete Denture Rational for Arranging Posterior Teeth in Balanced Occlusion. Axioms for Artificial Occlusion - SEARS (1952) Basic Principles and Requirements of a stable occlusion in complete denture for tissue preservation (Winkler). The application of physical laws in relation to lever can be expressed by the following Factors affecting Balanced Occlusion. Concepts of balanced versus non-balanced Occlusion. Recording of Occlusion for removable prosthodontics. Selection of Artificial Teeth of completely edentulous patients. Teeth arrangement and principles that should be followed during managing complete denture cases Prosthetic Problems and possible solutions in Setting –up of teeth for skeletal Class II and Class III arch relationship Occlusion of Removable Partial Denture. Occlusion of Maxillary Single Denture. Occlusal correction for Removable Prosthesis. Occlusion of Overdentures. & dental implants Digital Occlusion . Occlusion Course Outline

5. COMPLETE DENTURE OCCLUSION It is an important factor for maintaining the stability of complete dentures, with the least amount of trauma to the supporting tissues.

6. Enhancement of denture stability, retention and support. Preservation of the remaining tissues. Proper masticatory efficiency. Enhancement of phonetics and esthetics. Objectives

7. Is the Resistance of Denture to Tipping (Rocking, torsional forces ) during function. Stabilit y

8. Philosophies of Denture Occlusion Many philosophies of arranging denture occlusion No definitive scientific studies prove one occlusal scheme clearly superior.

9. Cuspless teeth Improper tongue space Denture dislodged by eating Usually, new denture wearer. Certain food stuffs are more difficult to consume. Habit of eating on anterior teeth only Overextended flange Instable denture Using Non-Cusped teeth Lack of interdigitation of posterior teeth. Unbalanced occlusion and articulation Cuspal interference Teeth outside the ridge Cramped tongue: Restricted tongue space Occlusion Border Base General problems

10. To occlude means to “close”. Occlusion is the act or process of closure Occlusion

11. Dental Occlusion The contact of the opposing surfaces of teeth of both jaws The static relationship between the incising or masticating surfaces of the maxillary and mandibular teeth, after jaw movement has stopped and tooth contacts are identified .

12. Dental Articulation while articulation deals with the dynamic contact relationship of the opposing teeth as the mandible moves to and from eccentric relation or during function.

13. The contact relationship between the occlusal surfaces of teeth during function. It is the DYNAMIC contacts relationship of the teeth as the mandible moved to and from eccentric relation. Dental Articulation

14. EXCURSIVE MOVEMENT Movement occurring when mandible moves away from maximum intercuspation OCCLUSAL INTERFERENCES Undesirable contacts occurring during lateral movements

15. Working side Non working (balancing) side That side of the mandible that moves toward the median line in a lateral excursion. The side toward which the mandible moves in a lateral excursion

16. Working side Non working (balancing) side The non-working side condyle shifts and move downward, forward and inward along the opposite side mandibular fossa The condyle rotates and shifts laterally , along with a possible small shift up, or down, or forward or backward , depending upon the shape of the mandibular fossa

17. Spee’s curve It is the   Anteroposterior  curve of occlusion. The anatomic curvature of the occlusal alignment of the lower teeth beginning at the tip of the lower cuspid and following the buccal cusps of the natural bicuspids and molars continuing to the anterior border of the ramus. Compensating curves

18. The Curve of Spee is basically a part of a circle (8-inch diameter) which has its circumference as The curvature of this arc would relate, on average, to part of a circle with a 4-inch radius. Spee’s curve the anterior ramus of mandible. Ideally, it is aligned so that a continuation of this arc would extend through the condyles.

19. A flat or mild curve of Spee was essential to an ideal occlusion for natural teeth

20. The pull of the main muscle of mastication, the  masseter , is at a perpendicular angle with the curve of Spee to adapt for favorable loading of force on the teeth. The long axis of each lower tooth is aligned nearly parallel to their individual arch of closure .

21. Curve of Wilson Curve of Wilson It  is the across arch curvature or posterior occlusal plane. Arc of the curve, which is concave for mandibular teeth and convex for  maxillary teeth  are defined by a line drawn from left mandibular first molar to right mandibular first molar.

22. The buccal cusps of the lower posterior teeth are slightly higher than the lingual cusps, and a line drawn through the buccal and lingual cusps of the teeth on the other side forms a lateral curve of Wilson Curve of Wilson Curve of Wilson

23. Monson’s curve It is a curve in which each cusp and incisal edge touches or conforms to a segment of a sphere 20 cm ( eight inches) in diameter with its center the glabella.

24. Sphere of Monson: A three-dimensional (3-D) sphere combining the anterioposterior curve and the mediolateral curve, with the mandibular incisal edges and cusp tips touching the sphere

25. The compensating curve of the artificial occlusion corresponds to a combination of these curves in natural teeth. It is considered one of the most important factors in establishing balanced occlusion

26. Bonwill’s Triangle

27. Effect Of Bonvill’s equilateral Triangle theory on Complete Dentures The construction of average articulators is generally in accordance with Bonwill’s theory, and Monson’s pyramid . This theory proposed that teeth move in relation to each other as guided by the condylar controls and the incisal point. Christensen (1959)

28. VERTICAL DIMENSION OF OCCLUSION

29. The distance measured between two selected anatomic or marked points (usually one on the tip of the nose and the other one on the chin) when occluding members are in maximal intercuspation. GPT 9 VERTICAL DIMENSION OF OCCLUSION

30. Inter-alveolar distance inter-ridge distance The vertical distance between specified positions on the maxillary and mandibular alveolar ridges at the occlusal vertical dimension. Checked on mounting diagnostic casts

31. The vertical dimension of the face when the mandible is in rest position . VERTICAL DIMENSION OF REST

32. Interocclusal distance (Free way space) The space between the maxillary and mandibular occlusal surfaces when the mandible is in the rest position . It ranges from 2-4 mm .

33. V D R V D O V D R - F W S = V D O 2 to 4 mm.

34. No Translation 2 to 4 mm. F W S

35. VALUE OF VERTICAL DIMENSION Biological importance of correct registration of the occlusal vertical dimension; the patient can: 1 - Masticate his food efficiently. 2 - Speak without impediment. 3 - Present a normal facial appearance. 4 - Experience a minimum amount of discomfort in using his dentures.

36. 1- Inharmonious facial proportions (Appearance). 2- Flexor muscles are in constant strain. 3- The lips are unnaturally separated and have a strained appearance. 4- The free-way space will be obliterated, inability to find comfortable resting position. 5- Clicking of teeth may occur during speech and mastication. Sequel Of Improper Registration Of V.D.0 . A . High Vertical Dimension Of Occlusion:

37. 6- Generalized soreness of the residual ridge. 7. Difficulty in swallowing and gagging sensation (Discomfort). 8. Loss of biting power and muscular fatigue. 9. Interference with speech . 10. Pain under the basal seat and trauma to the supporting structures. 11. Accelerate bone resorption. A . High Vertical Dimension Of Occlusion: Sequel Of Improper Registration Of V.D.0 .

38. High Vertical Dimension Generalized inflammation Flabby Tissue Obliterated free-way space High Plane of Occlusion

39. Angular cheilitis Esthetic complaints: Chin prominent Poor lip support (Insufficient OVD ) Establishing too little V . D.

40. Cheek Biting Angular Cheilitis

41. Indefinite pain location resembles neuralgia of cheek Lack of chewing power Minimal ridge discomfort Costen’s syndrome mild deafness, tenderness in TMJ, burning sensation of the tongue, throat and nose, dryness of the mouth. Insufficient OVD

42. The most retruded relation of the mandible to the maxillae when the condyles are in the most posterior unstrained position in the glenoid fossae from which lateral movement can be made, (within hinge movement). CENTRIC RELATION (GPT) 2005

43. A maxillo-mandibular relationship, independent of tooth contact, in which the condyles articulate with the anterior- superior position against the posterior slopes of the anterior eminences; in this position, the mandible is restricted to purely rotary movement; CENTRIC RELATION (GPT) 2009

44. The relation of the mandible to the maxilla with the mandible in its most retruded position . (GPT) 2005 CENTRIC RELATION

45. Is the only constant repeatable position within the functional limit to start constructing a stable occlusion CENTRIC RELATION

46. Dawson has defined this position as the rearmost, uppermost, midmost (RUM) position of the condyle in the fossa at which the medial pole of the condyle disc assembly is braced against the bony wall of the eminentia . The mandible is restricted to purely hinge movement. CENTRIC RELATION

47. Is the Maxillo -Mandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective discs , with the complex in the anterior superior position against the shapes of the articular eminencies. CENTRIC RELATION (Bone-to-Bone relation )

48. Whatever is the definition of centric relation it is reproducible , stable and functional position . The rearmost, uppermost, midmost (RUM) position of the condyle in the fossa The most posterior unstrained position in the glenoid fossae In the uppermost and rearmost position in the glenoid fossae In the anterior-superior position against the articular eminences

49. Centric relation is Reproducible, repeatable, recordable position and within the functional range of movements . Functional movements like chewing and swallowing are performed in this position , because it is the most retruded unstrained position. ( Patients appear to function comfortably in CR ) Centric relation is a border position and It remains constant throughout life. Importance of centric jaw relation ( Significance) Carroll , Woelfel & Huffman (1988)

50. It is the start point for developing occlusion. It is the horizontal reference position of the mandible, from which the mandible can move to any eccentric position and return back involuntarily. It is a reliable and consistent jaw relation, because it is bone to bone relation. An accurate centric relation record will orient the lower cast to the opening axis of the articulator in the same relationship as the patient's mandible relates to his/ her opening axis .

51. Is the most closed complete interdigitation of mandibular and maxillary teeth Irrespective of Condylar Centricity The relation of opposing occlusal surfaces at which the cusps of Maximal Intercuspation position the maxillary and mandibular teeth contact with maximum intercuspation irrespective to condylar position .

52. Maximal Intercuspation position Maximum intercuspation may or may not coincide with centric relation, depending on the position of the condyle. The complete intercuspation of the opposing teeth independent of condylar position GPT8

53. The occlusion of opposing teeth when the mandible is in centric relation, This may or may not coincide with the maximal intercuspal position ( in natural dentition) GPT 9 CENTRIC OCCLUSION

54. In most patients maximum intercuspation is located anterior to the centric relation by 0.5-1.5 mm measured in the horizontal plane. In 90% of individuals with full complement of natural teeth, maximum intercuspation does not coincide with centric relation of the jaws. CENTRIC OCCLUSION

55. The continuous line denotes maximal intercuspal position, the shaded line denotes the positioned centric relation. a b a b

56. In the edentulous patients, use the posterior border position (centric relation) which is repeatable, reproducible and within the functional range of movements.

57. For this reason, the relation of the mandible to the maxilla should be recorded in the most retruded position (C.R) and centric occlusion made to coincide with it

58. In the dentulous patients If maximum intercuspation is coincide with the centric relation ( the condyles are centered) , referred to Orthopedic stability . When such relation exists, forces can be applied to the teeth & joint without injury . This is considered a healthy normal occlusion

59. Orthopedic instability However, if maximum intercuspation occurs with the condyles being out of centricity , then both positions would not coincide , referred to as Orthopedic instability. This is considered as abnormal occlusion resulting in abnormal forces on the teeth and the joint

60. Recording Jaw relation for edentulous cases should be performed in the most retruded position and centric occlusion made coincide with centric relation (posterior border position) Why and how to solve the problem ??????? In the edentulous patients

61. Long centric or Freedom in centric The occlusal surface of the teeth could be altered to allow freedom of tooth movement in harmony with the rotation of condyle. From centric relation (CR) to habitual intercuspal position (HIP). Point centric HIP CR

62. Fossa: 1-2 mm antero -posterior and laterally No anterior contacts Maintain the vertical dimension Long centric or freedom in centric CR MIP

63. Centric occlusion with teeth present is a tooth to tooth relation whereas centric relation, is a bone to bone relation (Static positions)

64. In complete denture prosthodontics the relation of the mandible to the maxilla should be recorded in the most retruded position (C.R) with the position of the maximum planned intercuspation of teeth (centric occlusion) established to coincide with it.

65. Occlusion of teeth and mandibular position Ligamentous position: T his is the extreme position to which mandible can be displaced posteriorly. It is repeatable and reproducible. It is a point at the intersection of the right and left border positions of the Gothic arch.

66. T his position can be obtained by interdigitation of upper and lower teeth. 2.Tooth position (Maximum intercuspation): The maximum intercuspation position alters with abrasion and loss of the teeth as well as periodontal disorders.

67. It is the physiologic center of the mandibular muscle balance (center of muscular activity) It is normally coincide with tooth position . 3. Muscular position: Habitual Arc of Closure

68. Slide in Centric Q: Does the mandible really “slide” into MI from the Retruded Contact Position during closure (not chewing) ? A: No, it closes along an arched path which leads directly to MI position. Q: What is the name of this path? A: Habitual Arc of Closure (Muscular p.)

69. An occlusion other than centric occlusion Protrusive occlusion Lateral occlusi on ECCENTRIC OCCLUSION

70. If you don’t feel shame, then do as u wish

71. This relation exists when the jaws are in centric relation and the teeth are in maximum intercuspation at the accepted vertical dimension. Centric occluding relation

72. To re-establish the functional position of the mandible • Comfort • Esthetics • Phonetics • Functional efficiency • Structural balance Centric occluding relation Stability of complete denture & decrease alveolar bone resorption

73. Jaw relation record Centric occluding relation Eccentric occluding relation

74. Orientation relations ( Occlusal plane orientation) Vertical relation, and Horizontal relation: Centric relation ( Anteroposterior relation) Eccentric relation (lateral and protrusive relations) Three - dimensional record Centric and eccentric occluding relation

75. Orientation of occlusal plane. b. Cranio -maxillary orientation . 1. Orientation Relations

76. a. Orientation of occlusal plane. O. P. is a common plane established by the incisal edges and occlusal surfaces of the teeth. Aesthetic base. Functional base . Mechanical base . Determination of the occlusal plane It is usually curved and is therefore not strictly a plane] 1. Orientation Relations

77. 1. Orientation Relations a. Orientation of occlusal plane. b. Cranio -maxillary orientation: Orientation of maxilla in relation to base of skull and the hinge axis, recorded either by: Using face-bow transfer with adjustable articulator. Following BONWILL triangle.

78. What if patient doesn’t match articulator? Articulator aha Patient maha

79. Articulators

80. Articulators Therefore the distance from the condyle to the teeth is crucial We obtain a measurement of this distance with a facebow AHA MHA

81. The relationship between the upper model and the rotation axis of the articulator must be the same as the relationship between the maxilla and the skull base Hinge axis of patient and articulator Closure arch

82. 2. Vertical relation VDO: Distance between maxilla & mandible when teeth or wax rims contact in centric occlusion. Inter Occlusal Rest Space 2 to 4 mm V D O= V D R - F W S

83. The relationship of mandible to maxilla in a horizontal plane (in anteroposterior and side to side direction): 1-  Centric jaw relation.  2- Eccentric jaw relations . 3. Horizontal Relations

84. 3. Horizontal Relations The most retruded unstrained relation of the mandible to the maxilla at the established vertical dimension of occlusion. ( Anteroposterior relation) 1- Centric relation

85. For edentulous patients, use the posterior border position (centric relation) which is repeatable , reproducible and within the functional range of movements. Centric Occlusion made to coincide with CR at the accepted V.D.O . 3 Dimensions Centric occluding relation

86. Centric relation is a border position. Centric relation is the horizontal reference position of the mandible. Centric relation is Reproducible , repeatable, recordable and within the functional range of movements. An accurate centric relation record will orient the lower cast to the opening axis of the articulator in the same relationship as the patient's mandible relates to his/ her opening axis . Significance of centric relation

87. Is the most closed complete interdigitation of mandibular and maxillary teeth Irrespective of Condylar Centricity. Maximum intercuspation may or 3. Horizontal Relation 2- Maximum intercuspal position may not coincide with centric occlusion, depending on the position of the condyle .

88. 3- Eccentric occluding relation Protrusive relation, Right lateral relation, and Left lateral relation. 3. Horizontal Relation An occlusion other than centric occlusion

89. Eccentric occluding relation

90. Protrusive occlusion Lateral occlusion The occlusal contact relationship that exists when the mandible is moved forward The occlusal contact relationship that exists when the mandible is carried laterally ECCENTRIC OCCLUSION

91. Horizontal relations of the jaws Horizontal relations between the jaws and teeth may be considered to exist antero-posteriorly in the sagittal plane and laterally in the coronal plane

92. Condylar inclination is the angle formed by the articular surface of the temporal bone as related to a horizontal line, which is parallel to the Frankfort plane . The condylar guidance is the only factor given by the patient. Protrusive occlusion

93. The angle formed by the steepness of the articulator surface that is related to a horizontal plane is called the sagittal inclination ( Condylar inclination)

94. Christensen’s Phenomenon  A gap occurring in the natural dentition or between the opposing posterior flat occlusal rims when the mandible is protruded (posterior open bite). It can lead to instability in full dentures unless compensating curves are incorporated into the dentures .

95. Non-working side , condyle & disc move downwards, forwards & inwards along opposite side of mandibular fossa Working side (side towards which mandible is moving) Working condyle rotates & shifts Lateral Movement . (Bennett Shift) Lateral Movement . (Bennett Angle) W B Lateral occlusion

96. Bennett Angle: The angle formed between the sagittal plane (assumed straight protrusive path) and the Bennet angle Bennet movement path of the advancing (orbiting) condyle during lateral mandibular movements as viewed in the horizontal plane .

97. Bennet Angle Angle at which the non-working side condyle moves medially away from a sagittal reference plane as viewed in horizontal plane during lateral movement Bennet angle Bennet movement Bennet Movement Bodily lateral movement of working side condyle OLD concept

98. It is the lateral bodily shift of the mandible resulting from movements of the condyles along the lateral inclines of the mandibular fossae in lateral jaw movement . Laterotrusion ( Bennett movementXX ) With Immediate side shift Bennet angle (7 degree) Bennet angle (15 degree) Without Immediate side shift NEW concept

99. Immediate side shift Immediate side shift represents the mandibular side shift in which the orbiting (non-working) condyle moves straight medially in the two dimensional graphic tracings With Immediate side shift Bennet angle (7 degree) Bennet angle (15 degree) Without Immediate side shift

100. Bennett Angle Angle at which the non-working condyle moves inward during a lateral excursion, measured in degrees a gainst the sagittal plane. Progressive side shift (in degrees )= Bennett angle.

101. 1- Movement in the working side Laterotrusion In the past known as Bennett movement Condylar movement on the working side during a lateral excursion Movements are A- Rotation: in the lower compartment B- Translation (Bennett movement): in the upper compartment Rotates and shifts laterally, along with possible shift up, down, forwards or backwards, depending upon shape of mand . fossa

102. Mediotrusive Also called non-working or balancing movement A movement of the mandibular condyle in a medial direction, towards the midline. Nonworking condyle A- Translation moves downwards, forwards & inwards B- Rotation about a vertical axis, 2- Movement in the non working side

103. Determines the medial wall of the condylar fossa . (Not important for denture construction) Fisher Angle: The angle formed by the inclinations of the protrusive and nonworking side condylar paths as viewed from the sagittal plane. The angle formed between the sagittal lateral and the sagittal protrusive condylar paths.

104. = Balance + Occlusion BALANCE = When forces act on a body in such a way that no motion results, there is balance or equilibrium. DENTAL OCCLUSION = Relationship between the occlusal surfaces of the maxillary and mandibular teeth when they are in contact . Balanced Occlusion

105. Balanced Occlusion (Centric and eccentric occlusion) The Bilateral simultaneous contact of teeth in centric and eccentric positions. (GPT 9)

106. There should be no interferences during movement from centric position to eccentric positions. The movements should be in harmony with TMJ & neuromuscular control.

107. This occlusion could cause tipping of the denture in the posterior region. Thus simultaneous anterior & posterior contacts are required when mandible is protruded . Condylar Angle determines the amount of this space

108. But this occlusion could cause tipping of the denture in the posterior region. Thus simultaneous anterior & posterior contacts are required when mandible is protruded.

109. Balanced Occlusion (Centric and eccentric) Protrusive State of equilibrium of the denture bases in relation to their supporting structure when the opposing teeth contact.

110. Balanced Articulation (Free Occlusion) The Bilateral simultaneous contact of the anterior and posterior teeth in excursive movements. ( GPT 9)

111. The bilateral, simultaneous occlusal contact of teeth in maximal intercuspal position, in eccentric positions and in excursive movements . Bilateral Balanced Occlusion/Articulation ( GPT 11)

112. There should be no interferences during movement from centric position to eccentric positions. The movements should be in harmony with TMJ & neuromuscular control.

113. Eliminate anterior interferences Anterior interference No simultaneous contact Anterior interference

114. Anterior incisal clearance should be provided during all posterior masticatory function.

115.  A gap occurring in the natural dentition or between the opposing posterior flat occlusal rims when the mandible is protruded (posterior open bite). It can lead to instability in full dentures unless compensating curves are incorporated into the dentures . Christensen’s Phenomenon

116. Means that when the patient produce a protrusion with well adapted occlusal rims, there will be a v- shaped gap between the rims in the molar region. Sagittal Christensen phenomenon

117. Means that when the patient produce a lateral excursion with well adapted occlusal rims, there will be a v shaped gap between the rims in the molar region on the balance side. On the working side there will be contact between the upper and the lower rims. The Transversal Christensen phenomenon

118. Adjust Protrusive Guide for Maximal Interdigitation Protrusive and lateral records to set condylar inclination

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