Treatment planning for the class 0, 1A, 1B dental arches Dr.. Peter Hermann Dr Reminder: Torquing movement on tooth supported denture : • no movement Class 1 • movement in one direction (depression) Class 2 • movement in more than one directions (tilting) Class 3 Class 0 • Single-Tooth Restorations • No actual missing teeth • Large areas of missing coronal tooth structure can be replaced while that which remains is preserved and protected Destruction of tooth structure Modifying contours to refine occlusion Esthetic needs Defective position in the arch Incisal restorations Single-Tooth Restorations in Class 0 • Intracoronal • Extracoronal Inlay Onlay • Sufficient tooth structure exist to retain and protect restoration Partial veneer crown Full veneer crown Ceramic veneer • Insufficient coronal tooth structure to retain the restoration within the crown of the tooth • Dowel core restorations • Little or no coronal tooth structure, a core may not have sufficient resistance to dislodgement without a dowel that extends into the root Ceplatek-Captek • The most common method of producing crowns and bridges utilizes the lost wax technique ~ which requires firing several layers of porcelain onto a cast metal framework. • CAPTEK crowns and bridges use a technology which does not require any waxing or casting to produce the copings or bridge understructures for ceramic application. • Instead, a material called CAPTEK P is applied directly to a refractory die by hand. • CAPTEK P is an alloy of Gold, Platinum & Palladium. This material establishes the capillary network for the application of the second layer of material - CAPTEK G. • CAPTEK G is a gold layer which covers the first layer and, when heated, interlocks completely with the CAPTEK P giving the CAPTEK coping or bridge understructure its' strength. High strength porcelain crowns HSPC • High strength underlying core to support veneering porcelain which gives the final shape and aesthetic attributes required for the restoration. • No need for metal substructure • CAD/CAM systems Fundamentals of Class 1: • • • Tooth support: total abutment support available Torqueing movement on occlusal or incisal surface of constructed denture: curvature of the arch in the edentulous region determines whether the pontics will act as a lever arm on the abutment teeth Secondary retention can compensate torquing force produced Frequency of edentulous arches classified Upper jaw Lower jaw Class 1A • • • • One or more axis lines Pontics lie in the interabutment axis line No torquing forces produced on the FPD Tooth supported partial denture to be constructed • FPD recommended • Primary (adjacent to the edentulous space) abutments to support the prosthesis Class 1A • Lateral span: maximum of 4 missing teeth with teeth remaining anterior and posterior to it • Missing lower incisors • Missing upper incisor • Primary abutment only when tooth adjacent to edentulous space are Type I or Type II • Tooth posterior to distal abutment of strategic importance Abutment Evaluation • Abutment teeth must be able to withstand the forces normally directed to the missing teeth, in addition to those normally applied to them. Type I Type II Type III Canines 1. and 2. premolars Lower incisors Upper central incisors Upper lateral incisors 1. and 2. molars Wisdomteeth • According to crown-root ratio, root configuration, periodontal ligament area and position in the arch. Class 1B • One or more axis lines • Pontics lie outside the interabutment axis line • Torquing movement produced • Sufficient number of remaining teeth in adequat position can compensate this torque Class 1B • Completely tooth supported denture to design • FPD recommended • Secondary (remote from the edentulous space) abutment is to strengthen the FPD Class 1B • (Even) one missing canine • Edentulous space in the arch combined with a missing canine • Upper incisors • Arch curvature has its effect on the stresses occuring in a FPD • Pontics outside the interabutment axis line act as lever arm, which can produce torquing movement • To offset the torque additional retention needed by secondary abutments Removable Partial Denture in Class 1A and 1B • Accident (severe loss of tissue in the edentulous ridge) • Embryonological anomalies • Limited patient finances • Unfavorable attitude toward tooth preparation • Treatment simplification • Totally tooth borne base plate design ! Implant-Supported Fixed Partial Dentures • Solitair implant (no destructive effects of retainer crown preparation) • No distal abutment (implants at both ends preferred) • Consider: maxillary sinus, inferior alveolar nerve Cantilever Fixed Partial Dentures • Abutments at one end of pontic only, with the other end remaining unattached • Pontic acts as a lever • When pontic loaded occlusally, the adjacent abutment tends to act as a fulcrum, with a lifting tendency on the farthest retainer • Torqueing forces produced depend upon the distance that the pontic lever arm extends Cantilever Fixed Partial Dentures • Mesial : edentulous area located anterior abutment teeth-abutments only at distal end of pontic • Distal: edentulous area located posterior abutment teeth- abutments only at mesial end of pontic • Mesiodistal: No see-saw! • Distal-distal: edentulous area located bilateral abutment teeth Mesial Cantilever FPD • Routine FPD (abutments at both end) always possible • Replacing a premolar • Replacing a lateral incisor Distal Cantilever FPD • • • • Replacing a second molar Replacing a first molar Occlusal contact limited Pontic should be kept as small as posibble, more nearly representing a premolar than a molar Materials Biomechanics Esthetics • Metal • Veneer fused to metal base • All-Ceramic • Acrylic resin Appearance zone! Two opposing ceramic surfaces! Thank You for Your Attention!