DEN203 Prosthetic Dentistry II Lecture Notes PDF

DEN203 Prosthetic Dentistry II Lecturer: Dr. Rana Turunç Oğuzman & Dr. Demet Ayvalıoğlu E-posta: [email protected] Articulators Altınbaş Üniversitesi Rana Turunç Oğuzman [email protected] DEN203 Protetik Diş Tedavisi 2 Occlusion • Dynamic biological relationship of comp...

DEN203 Prosthetic Dentistry II Lecturer: Dr. Rana Turunç Oğuzman & Dr. Demet Ayvalıoğlu E-posta: [email protected] Articulators Altınbaş Üniversitesi Rana Turunç Oğuzman [email protected] DEN203 Protetik Diş Tedavisi 2 Occlusion • Dynamic biological relationship of components of the masticatory system that controls tooth contacts during function and dysfunction • It is the integrated action of the jaw muscles, temporomandibular joint and teeth Occlusion OCCLUSION-DEFINITIONS • Intercuspal contact (IC) Contact between cusps, fossa, marginal ridges of opposing teeth OCCLUSION-DEFINITIONS • Intercuspal position (ICP) Position of the jaw when teeth are in IC OCCLUSION-DEFINITIONS • Maximum intercuspation (MI) Contact of teeth with maximum clenching Centric relation (CR) • The maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective discs as a complex in the anterior-superior position against the slopes of the articular eminence. • This position is independent of tooth contact OCCLUSION-DEFINITIONS • Centric occlusion (CO) • The tooth contact position when the jaw is in centric relation • Tooth contact (CO) when the jaw is in CR may be more retruded than at ICP Postural jaw position (PJP) • Position of the jaw when an individual is sitting or standing upright when relaxed • A free way space or speaking space is present Occlusal vertical dimension (OVD) • The vertical height of lower third of the face when teeth contact in ICP Lateral jaw positions • Working side ➢The side of the jaw that moves laterally away from the midline ➢Chewing side (where the chewing occurs) Lateral jaw positions • Non working/balancing ➢The side of the jaw that moves towards midline ➢The side opposite the chewing side Lateral jaw positions • Bennett movement: The bodily lateral movement of the mandible resulting from the movements of the condyles along the lateral inclines along the mandibular fossa Lateral jaw positions • Bennett Angle: Angle formed by movement of balancing condyle with sagittal plane during lateral jaw movement Mandible Movements Excursions of the mandible in 3 directions ▪ Downward movement-opening of the mouth Mandible Movements • Forward movement-protrusive ➢Anterior translation of the condyles down the slope of the articular eminence-condylar path Mandible Movements • Lateral movements –sideways ➢working side-to which the mandible moves- immediate side shift &rotation around vertical axis ➢non working side-condyle moves down and medially, Bennett Angle Overjet • The horizontal overlap of the incisors. • The relationship between upper and lower incisors in the horizontal plane. • Normally the incisors are in contact with the upper incisors ahead of the lower by only the thickness of the upper edges ie 2-3 mm overjet is the normal relationship. • Increased overjet- more than 3mm • Reduced overjet - less than 2 mm • Negative or reverse overjet – the lower incisors are ahead of the upper incisors Overjet • Overjet is measured from the labial surface of the lower incisor to the labial surface of the upper incisor. • Record the distance for both central incisors. • Get used to making the measurement in the middle of each incisal edge, keeping the ruler parallel to the occlusal plane. Overbite • is defined as vertical overlap of the incisors • The overlap of the lower incisors by the upper incisor in the vertical plane. • Normally the lower incisor edges contact the lingual surface of the upper incisors at or above the cingulum. • Normal overbite – 2 - 3 mm • Increased or Deep bite – more than 3 mm • Reduced overbite – less than 2 mm. Overbite • Complete overbite – An overbite in which the lower incisors contact either the upper incisors or the palatal mucosa. • Incomplete overbite –openbite An overbite in which the lower incisors contact neither the upper incisors nor the palatal mucosa. Crossbite • Deviation from the normal buccolingual relationship; may be anterior / posterior / or unilateral / bilateral . • Anterior crossbite This can either be anterior in which case one or more upper incisors are in lingual occlusion the lower incisors. • Under bite – The lower front teeth protrude beyond the upper teeth . Also known as an anterior crossbite. Normal OJ,OB Increased OJ,OB Reversed OJ,Crossbite Increased and complete OB Anterion Openbite and Posterior Unilateral Crossbite Articulator • Articulator is defined as a “mechanical device which represents the temporomandibular joints and the jaw members to which maxillary and mandibular casts may be attached to simulate jaw movements” Uses Of An Articulator • To diagnose the state of occlusion for both the natural and artificial dentition. • To plan dental procedures based on the relationship between opposing natural or artificial teeth • To aid in fabrication of restorations • To correct and modify completed restoration. • To arrange artificial teeth. Advantages • Properly-mounted casts allow the operator to visualize the patient’s occlusion, especially from the lingual view. • Patient cooperation is not a problem when using an articulator once the appropriate interocclusal records are obtained from the patient. • Refinement of complete denture occlusion in mouth is extremely difficult because of shifting denture bases and resiliency of the supporting tissue. This difficulty is eliminated when articulators are used. • Reduce chair time, patient’s appointment time. Components of An Articulator Upper Member • It is a triangular frame with the base of the triangle placed posteriorly. • The apex of triangle contains a provision to accommodate the incisal pin. • Two condylar elements are seen projecting on either side of the base of the triangle. • They articulate with the condylar guidance of the lower member. • The maxillary cast is attached to the upper member during articulation. Lower Member • L shaped frame with horizontal and vertical arm. • The horizontal arm is triangular in shape and corresponds to the upper member. • The apex of the triangle of the horizontal arm contains the incisal guide table. • The vertical arm is rectangular containing the condylar guidance slot at the upper position. Incisal Guide Table • The part of the articulator which maintains the incisal guide angle • It gives the incisal guidance of the articulator. • It can be described as a very short cylindrical whose upper surface is concave. • The vertical rod should rest on the center of the incisal guide table during articulation. • The incisal guide angle is fixed and non customizable. Incisive Rod • It helps to keep a fixed distance between the upper and lower members at the anterior end. • The vertical rod has a pointed tip, which should rest on the center of the incisal guide table during articulation. • The tip of the incisal guide pin is the anterior reference point in this articulator. • The incisal edge of the maxillary incisors at the midpoint of the occlusal rim should touch the tip of the incisal pin during articulation. Elements Of An Articulator • horizontal axis of rotation: variability of the position of the horizontal axis of rotation in relationship to the maxillary dental cast Elements Of An Articulator • condylar inclination/fossa components: variability of the angle of the eminentia, directional guidance of the superior, posterior and medial walls of the fossa, and ability to simulate laterotrusive movement Elements Of An Articulator • intercondylar distance: adjustability of the distance between the vertical axis of rotation Elements Of An Articulator • Benett angle/Benett movement: adjustability of the angle and capability of stimulating sideshift movement Elements Of An Articulator • incisal guidance: adjustability and ability to stimulate the anterior guidance of the natural dentition Types Of Articulators • Simple Hinge • Average Value (Plane-line) • Semi Adjustable • Fully Adjustable Simple Hinge • Single hinge movement only • No lateral movement • Smaller than patient’s jaws • Very limited value in restorative dentistry and prosthodontics but may allow preliminary evaluation of static tooth arrangement on study casts Average Value • Condylar angle fixed at 30° • No provision of adjustment for lateral mandibular shift • Adjustable incisal guidance • Produce an approximation of condylar movements and used to design and prepare complete dentures and simple restorations Semi - Adjustable • Allow adjustment of condylar inclination and Bennett angle • Intercondylar width fixed at 110mm • Condylar and Bennet angle are obtained from protrusive and lateral occlusal records or are set on average values • Incisal guidance are made by reference to the overbite and overjet of anterior teeth, or if the teeth are lost, an average value can be set. Semi Adjustable • Recommended for most dental restorations • More accurate than average value • Allows increase of OVD by raising the height of articulator pin Semi- Adjustable Arcon • Arcon • Fossa in the upper member • Condylar sphere in the lower member • Duplicates arrangement of TMJ Semi- Adjustable Arcon Semi Adjustable – Non Arcon • Condylar ball is attached to upper member • Slot mechanism attached to lower member Semi Adjustable – Non Arcon Fully Adjustable • Complex • Designed to duplicate TMJ features • Condylar settings may be determined by pantographic and stereographic records Fully Adjustable Facebow • An instrument that records the spatial relationship of the maxilla and transfers this relationship to the articulator Facebow Mounting Casts on Articulator • https://youtu.be/rmfrRB-NPYI