L17-Antonoff-Clinical Significance of Occlusion for Fixed Prosthodontics.pdf

Occlusion, Vertical Dimension & Maxillo-mandibular Records for Fixed Prosthodontics Lisa R. Antonoff, DDS, FACD Clinical Associate Professor Department of Prosthodontics NYUCD Goals • Selection of the appropriate maxillomandibular record indicated in a variety of clinical situations • Signs and sy...

Occlusion, Vertical Dimension & Maxillo-mandibular Records for Fixed Prosthodontics Lisa R. Antonoff, DDS, FACD Clinical Associate Professor Department of Prosthodontics NYUCD Goals • Selection of the appropriate maxillomandibular record indicated in a variety of clinical situations • Signs and symptoms of each of the four components of occlusion • Why vertical dimension of occlusion (VDO) may be lost • Consequences of loss of VDO Styles of Occlusion • Bilateral balanced occlusion • Unilateral balanced occlusion • Mutually protected occlusion Styles of Occlusion • Bilateral balanced occlusion – Developed by von Spee & Monson – Maximum number of teeth should contact in all excursive movements of the mandible – Complete dentures Styles of Occlusion • Unilateral balanced occlusion – Developed by Schuyler – aka Group function – Elimination of all tooth contact on the mediotrusive (non-working) side • Prevents destructive obliquely directed forces • Reduces excessive wear – No posterior teeth contact in protrusive – Used when canines are periodontally compromised Styles of Occlusion • Unilateral balanced occlusion Styles of Occlusion • Mutually protected occlusion – Developed by D’Amico, Stuart & Stallard – Overlap of anterior teeth prevent posterior contacts in all excursive movements – Anterior teeth protect posterior teeth in all excursive movements – Posterior teeth protect anterior teeth in intercuspal position… “mutually protected” Styles of Occlusion • Mutually protected occlusion Class III Lever F: Fulcrum – TMJ E: Effort (force) – muscles L: Load (resistance) – food Styles of Occlusion • Mutually protected occlusion – Requires periodontally healthy anterior teeth – Requires healthy jaw relations • Class II & III occlusion, cross-bite or reverse plane of occlusion situations cannot support this style of occlusion • Healthy supporting tissues • Full complement of teeth Styles of Occlusion • Mutually protected occlusion Styles of Occlusion • Mutually protected occlusion • Protrusive movement CENTRIC PROTRUSIVE Occlusal Interferences NON-WORKING (medio-trusive) WORKING (Latero-trusive) Purpose of Maxillo-mandibular Records 1. Minimize the orientation error of the working & opposing casts on the articulator 2. Provide support &/or stability to the casts during mounting 3. Reduce the extent of intraoral adjustment to restorations prior to cementation 4. Decrease the number of occlusal interferences Freilich et al. JPD 1992 When do we need this type of record? Ideal Occlusion • Requires minimum adaptation for the patient • Closure: – Posterior teeth in solid & even contact – Anterior teeth are in slightly lighter contact • Occlusal forces directed in the long axes of the teeth Ideal Occlusion • Excursions: – No contact of posterior teeth in lateral or protrusive movements • In upright posture, posterior teeth contact more heavily than do anterior teeth Pathologic Occlusion • Etiology of Traumatic Occlusion  Inadequate posterior support  Excessive vertical and horizontal overlap due to supra-eruption of anterior teeth  Traumatic anterior guidance Pathologic Occlusion • Signs & Symptoms 1. Teeth • Open contacts • Abnormal wear • Fremitus 2. Periodontium • • • • Widened PLD space Periodontal defects Mobility Rapid tooth migration Pathologic Occlusion • Signs & Symptoms 3. Musculature • Acute or chronic muscle pain on palpation 4. TM Joints • Pain, clicking or popping Pathologic Occlusion • Inadequate posterior support – – – – – – – – Supra eruption Tilting & Drifting Loss of proximal contacts Negative effects on the supporting structures and occlusion Loss of more teeth Excess anterior teeth wear Loss of vertical dimension of occlusion Limited restorative interarch space Conformative Dentistry v. Reconstructive Dentistry Conformative Dentistry • Use maximum intercuspation • No change to vertical dimension of occlusion • Hand articulation vs. Interocclusal record Type of records depends on clinical situation Tooth-bound single unit Paola Cohen-Imach, DDS Adequate Posterior Contacts Paola Cohen-Imach, DDS Adequate Anterior Guidance *No Interocclusal record needed* Multiple units with NO distal posterior support Paola Cohen-Imach, DDS *Interocclusal record needed* Bite Registration Materials for Fixed Restorations • Acrylic – Rigid – Technique Sensitive – Can get locked into an undercut • PVS – User friendly – Sets at different speeds (classic, fast, ultra-fast) – Easy to trim – More dimensionally stable – Elastic Inadequate anterior guidance & inadequate posterior support Paola Cohen-Imach, DDS Necessary Records { *Facebow registration *Interocclusal records (Centric & Protrusive) *Custom incisal guide table Reconstructive Dentistry Reconstructive Dentistry • Use centric relation record • Possible change to vertical dimension of occlusion • Unstable occlusion Reconstructive Dentistry • Records needed: – – – – Vertical dimension of occlusion Centric relation record Face bow record Protrusive record / custom incisal guide table Centric Relation Record • Definition of Centric Relation: – condyles articulate in the most anteriorsuperior position against the slopes of the articular eminences • Independent of tooth contact • Reproducible • Physiologically acceptable position Centric Relation Records • A CENTRIC RELATION RECORD provides the orientation of mandibular to maxillary teeth in CENTRIC RELATION in the terminal hinge position, in which opening and closing are purely rotational movements. Centric Relation Record • Three techniques – Chin-point guidance – BILATERAL MANIPULATION • Most accurate – Unguided Centric Relation Record • Bilateral manipulation Centric Relation Record • Bilateral manipulation Courtesy of prosthopedia.org Courtesy of prosthopedia.org Face Bow Record • Relates the maxillary cast to the upper member of the semi- or fully- adjustable articulator • Provides more accurate relationship of maxillary teeth to condyles • Transverse horizontal axis/hinge axis • Repeatable Courtesy of prosthopedia.org Custom Incisal Guide Table • Diagnostic wax-up --> provisional restorations • Make protrusive record and set condylar angles • Mix acrylic and move casts to generate the custom incisal guide table • Guides in wax up of lingual contours of final restorations Custom Incisal Guide Table MI-CO Courtesy of Dr. Jonathan Wiens prosthopedia.org What is Vertical Dimension of Rest? (VDR) • The postural position of the mandible when resting comfortably in an upright position (physiologic rest position) • Muscles are in a state of minimal contractual activity • Protects the dentition VDR – VDO = Freeway Space Average Freeway Space ~3mm Assessing VDR • Swallowing • Phonetics • Esthetics What is Vertical Dimension of Occlusion (VDO) • The distance measured between two points when the occluding members are in contact • Supports facial profile • Maintains vertical space for restoration and prosthesis Loss of VDO • • • • • Loss of teeth Abrasion / Attrition / Erosion Bruxism Periodontal disease Congenital conditions – Amelogenesis or dentinogenesis imperfecta Photos courtesy of Dr. Mijin Choi Loss of VDO Loss of teeth Abrasion/ Attrition/ Erosion Congenital conditions Loss of VDO -Consequences Loss of VDO Consequences: - Loss of facial dimension - Loss of restorative space - Angular cheilitis - Possible diminished masticatory function - Possible phonetic compromise - Possible changes within TMJ(s) • Excessive interocclusal space at VDR Restoration of VDO Indications for restoration of VDO - Space for restorations - Function - Esthetics - Phonetics VDO Categories of loss of VDO: 1. Excessive wear with loss of occlusal vertical dimension 2. Excessive wear without loss of occlusal vertical dimension but with space available 3. Excessive wear without loss of occlusal vertical dimension but with limited space