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LECTURE 9: THE OCCLUSAL SURFACES: THE SELECTION AND ARRANGEMENT OF PROSTHETIC TEETH...

LECTURE 9: THE OCCLUSAL SURFACES: THE SELECTION AND ARRANGEMENT OF PROSTHETIC TEETH DR. CABUGOY ANTERIOR TEETH SELECTION SIZE SELECTION → it is an important stage in complete denture treatment because valuable inputs: satisfaction with a prosthetically created smile is significant in a → existing dentures patient’s decision to accept therapy → models or previous teeth → should meet patient’s expectations and should be approved → photographs → patients’ family members and friends opinion or input are also → set two different sizes on a piece of wax and place it under the considered in teeth selection protocol upper lip and find out which on the patient prefers → involving significant others in the decision making may be regarded as psychologically effective therapy (giving patients ADDITIONAL CLINICAL AND TECHNICAL CONSIDERATIONS IN what they want and facilitates patients taking ownership of the ANTERIOR TOOTH SELECTION selection decision) PATIENT PREFERENCES → carried out in a clinical office setting with color corrected → porcelain or acrylic lighting → a high smile line that displays a lot of gingiva would benefit → window light from north side as well as on the south side from the selection of a less tapered mold with a long contact point GUIDES IN TEETH SELECTION AND ARRANGEMENT → current or previous prosthetic teeth OVERDENTURES AND IMPLANT DENTURES → old study casts → implant abutments create areas of limited interocclusal space → photographs wherein patient is smiling → use larger square mold acrylic unlayered teeth → children’s photos OPPOSING NATURAL TEETH FACTORS THAT SHOULD BE AGREED ON WITH THE PATIENT → porcelain can be very abrasive and can contribute to the wear and destruction of opposing teeth’s enamel Tooth Color same, lighter or darker → acrylic teeth is preferred for dentures that oppose natural teeth Tooth Size same, larger or smaller MATERIALS FOR DENTURE TEETH Tooth Shape same, curved, or straight, amount of wear → porcelain teeth should only be used if the opposing dentition is also porcelain (as in set of dentures) because porcelain can After Selection and Arrangement: rapidly wear opposing enamel and restorations Midline same or moved left/right o has excellent color stability and superior wear resistance Occlusal Plane same or tilted, moved up/down, more or less o porcelain anterior teeth have two small plated pins visible o porcelain posterior teeth have hollowed out center or diatoric Dental Arch same or moved in/out, more or less curved or → acrylic teeth should be better designed for single complete flat, more or less visible prostheses and RPD–to minimize wear of opposing dentition Lip Support same or too little/too much Unique Features same or incisal wear, chips, rotations, spaces, POSTERIOR TOOTH MOLDS AND CUSPAL ANATOMY restorations Denture tooth molds are often narrower than the natural teeth they replace. Gingival Color same or less/more pigmented, custom shading OBJECTIVES When planned improvement means change, work within the range (1) A bolus of food can be penetrated and chewed with less that the patient can accept and assess the tolerance and motivation effort of your patient for change. (2) There is less displacement of the denture on mucosa (3) The polished surfaces of the denture can be sloped so that SHADE SELECTION the patient can learn to use his/her lip, cheek, and → the easiest decision for patient to make is the color of teeth they especially tongue muscles to help maintain the dentures in want place → shade selection process can be done by elimination from the set of complete shade guide, by selecting first the lightest and The improved attachment provided by titanium implants has darkest tabs dramatically improved the chewing ability of edentulous patients far more than any posterior tooth mold. Kirsten M. Abarquez | Cebu Doctors’ University | DMD-4B  LECTURE 9: THE OCCLUSAL SURFACES: THE SELECTION AND ARRANGEMENT OF PROSTHETIC TEETH DR. CABUGOY → a common esthetic error is to have bicuspids that appear to ARRANGING THE MANDIBULAR ANTERIOR TEETH small next to their adjacent cuspids → to create a minimum overbite/overjet for a standard anterior → posterior artificial teeth are manufactured with cusp inclines that setup–use the maxillary wax rim as a guide to position the vary from 30 degrees (anatomical) to 0 degree (flat) mandibular teeth → denture occlusion literature reports that patient subjectively → teeth should be visible during speech as appropriate to your prefer teeth with cusps and/or a lingualized occlusal contact patient’s anatomy pattern when compared with non-anatomic teeth → mandibular occlusal plane would be located at a height near the corners of the mouth so as to be visible with a “lips TEN LANDMARKS FOR COMPLETE DENTURE TEETH SETUP apart/mouth breathing” posture Four landmarks are located on the stone models: Incisive Papilla guide to the midline for the maxillary central incisors and the prominence of the incisors and cuspids Mandibular Bicuspid guides the bucco-lingual positioning of Residual Ridge the bicuspids Retromolar Pad Height width of the mandibular posterior teeth Normal Labiolingual Inclination Retromolar Pad Width width of the mandibular posterior teeth Normal Mesiodistal Inclination MANDIBULAR CENTRAL INCISOR POSITIONS → the central incisors are set at the midline and tipped slightly to the labial → the incisal edges of these teeth are set at the height of the maxillary wax occlusal rim to create minimal vertical overlap THE STANDARD ANTERIOR ARRANGEMENT with the maxillary central and canine teeth → anterior artificial teeth should be set into positions similar to that → a 1-2 mm horizontal overlap should exist between the lingual previously occupied by the natural teeth for esthetics and surface of the maxillary anterior teeth and the labial surface of speech the mandibular anterior teeth MIDLINE DETERMINATION MANDIBULAR LATERAL INCISORS → position the lateral incisors next to the central incisors, with their Incisive Papilla good static guide to the midline position long axes directed toward the residual ridge of the two upper central incisors in the → the incisal edge should be at the height of the wax occlusal rim denture → continue the 1-2 mm of horizontal overlap between the maxillary and mandibular anterior teeth Central Incisors set on this midline will have positions similar to those of the natural teeth MANDIBULAR CANINES Wax Registration Rim will have midline marked based on the → place the mandibular canines with the anterior ½ of the incisal appearance of the lips and face edge in symmetry with the lateral and central incisors → place the incisal tip at the same level as the lateral and central incisors → the neck of the tooth is slightly prominent and tilted to the distal Kirsten M. Abarquez | Cebu Doctors’ University | DMD-4B  LECTURE 9: THE OCCLUSAL SURFACES: THE SELECTION AND ARRANGEMENT OF PROSTHETIC TEETH DR. CABUGOY → when total anteroposterior length is greater than the space SETTING THE MAXILLARY ANTERIOR TEETH available–delete setting the maxillary second molars MAXILLARY CENTRAL INCISORS → option to delete the first bicuspids instead of maxillary second → the maxillary central incisors are the critical teeth to set molars → they are the most visible, establish the midline, and provide the esthetic support of the patient’s lip OCCLUSAL CONCEPTS FOR COMPLETE DENTURE OCCLUSION → set both central incisors and thus establish the midline before setting the lateral and canine Bilateral Balance use of anatomical molds → the long axes should diverge slightly on each side of the midline Monoplane or Non-Anatomical cuspless teeth, can also be used → excess wax should be removed so that you can see their long for balance concept with axes and orientation compensating curves → the teeth should not look like a “white picket fence” Lingualized Articulations combinations of upper anatomical and lower MAXILLARY LATERAL INCISORS nonatomical molds → place the maxillary lateral incisor next to the central incisor, with the neck slightly depressed LINGUALIZED ARTICULATION → arrange the incisal edge in symmetry with the central incisor and → occlusal contacts are focused between the maxillary palatal with the remaining anterior occlusal rim cusps and the mandibular fossae and lingual anatomy → this incisal edge is even with the remaining maxillary wax → the buccal cusps of both the maxillary and mandibular teeth occlusal rim and is therefore slightly elevated from the central appear realistic, but they do not touch in occlusion or excursions incisor → patients subjectively report chewing to be better than a flat → the incisal edge is parallel with the mandibular wax occlusal rim occlusal surface → follows the anteroposterior (Curve of Spee) and mediolateral MAXILLARY CANINES (Curve of Wilson) compensating curves → place the maxillary canine so that the anterior one half of the incisal edge is in symmetry with the lateral and central incisors ARRANGING MAXILLARY POSTERIOR TEETH as it curved around the labial contour of the wax occlusal rim TO LINGUALIZED ARTICULATION → the neck of the tooth must be prominent and the tooth tilted → the maxillary dentition is set with the palatal cusps in contact to slightly to the distal the mandibular central fosse and marginal ridges → the buccal cusp tips do not touch and the mandibular ARRANGING POSTERIOR TEETH compensating curves are followed → no scientific evidence exists to support the superiority of one → avoid placing occlusion on the ascending mandibular ridge by posterior tooth form over another deleting the maxillary second molar if necessary → the key objective is to position the posterior teeth so that patients will not bite their tongue and cheek muscles as they ARRANGING ANATOMICAL TEETH TO A chew BALANCED ARTICULATION → mandibular denture covers a smaller area than the maxillary → evaluating bilateral articulation one, it requires more muscular control for its stability → inspected after setting the maxillary and mandibular teeth → the posterior references of the center of the retro-molar pads → anatomical tooth molds will interdigitate precisely if they are set (RMPs) will place the mandibular occlusal plane at a level and in an articulator that has the incisal and condylar guidances set width similar to the natural dentition that is familiar to the to the same angles (ex.: 33 degrees) and if these teeth are set tongue at the same occlusal plane and radius distance from the → the buccolingual position of the posterior teeth and the posterior articulator condyles as when the teeth were designed arch form curves from the anterior position of the canines, over the bicuspid residual ridges, and posteriorly to within the width of the RMP SUMMARY OF TOOTH SELECTION AND ARRANGEMENT → accurate impression and cast reproduction NUMBER OF POSTERIOR TEETH SET → correct OCR needs to be made and accurately transferred to an articulator → avoid tooth contacts over the ridge where it inclines up to the → determination of neutral zone—teeth positioned in harmony retromolar pad with intraoral anatomy and circumoral muscle activity → tooth contact should be in the area where the resorbed ridge is → use tooth molds that are aesthetically pleasing and simple to parallel to the occlusal plane setup Kirsten M. Abarquez | Cebu Doctors’ University | DMD-4B