Selecting Denture Teeth Place reference marks on the occlusion rims to aid in tooth selection and placement Reference Marks for Selecting Anterior Teeth • Technician sets the teeth without seeing patient • Wax rim contours aid selection and setting: – Occlusal vertical dimension – Angulation of facial rims affects lip support – Overjet Maxillary Reference Marks Midline Position • Critical reference • #7 wax spatula • Score a line parallel the facial midline • Mark both rims Guidelines for Setting Anterior Teeth High Lip Line Corner of Mouth Angulation is as important as midline Midline of Teeth = Facial Midline • Mark midline on the wax Corners of the Mouth • Mark corners at rest (#7 wax spatula) • Position of distal of the canines Corners of the Mouth • Measure circumference between marks with Trubyte Auto-Rule • Size of 6 anterior teeth read off ruler (mm or by letter code A, B, etc.) High Lip Line • Highest point of upper lip when smiling • Cervical necks lie at or above this line • If shorter teeth are selected, esthetics compromised Palatal Midline • Through middle of incisive papilla & mid-palatal raphe • Extend onto land area • Check for symmetry – If not symmetrical, adjust rim Midline & Canine Reference • Line passing through distal of incisive papilla • Perpendicular to the palatal midline • Intersects cusp tips of the canines Natural Dentition Distal Aspect of the Incisive Papilla • Provides verification & tooth size selection • Use to verify the symmetry • On average, facial of central incisors should be 8-10 mm anterior to this line Mandibular Reference Lines Mandibular Reference Lines Center of ridge Posterior 1/2 way up retr omolar Mandibular Cast Land Area Ar ea Occlusion rim Center of ridge Anterior Middle of Retromolar Pads • Occlusal plane intersects • If occlusal plane is too low - tongue biting • Too high - strain as tongue struggles to replace the food bolus Center of Posterior Ridge • Maxillary lingual cusps should be centered over this line • Ensures denture stability • Reduces fulcruming forces during function Center of Anterior Ridge If anterior teeth are too facial to center of ridge, fulcruming tilting and dislodging occur Selecting Anterior Teeth • Combination of science and art • Measurement, formulas etc. are a starting point • Use vision and common sense Tooth Size Selection • Use existing teeth as a guide: – Too big or small? – If so, use your own judgment – Does patient like them? Do you? Tooth Size Selection Use existing teeth as a guide: – If acceptable, measure width and length – Compare to Trubyte mould guide chart • Central incisors dimensions listed • Tooth photos are life size Measuring Existing Teeth Tooth Size Selection • High Lip Line - indication of inciso-gingival length • Pre-extraction cast or photographs can be useful Tooth Size Selection • Corners of Mouth - use the Auto-Rule to pick a mould Shape Selection ¯ Tooth shape does not correspond to facial shape ¯ Trubyte system good starting point ¯ No proven male/female characteristics Shape Selection • Use existing teeth as a guide - do they look good • USE COMMON SENSE & OBSERVATION Use Negative Space • Look at interproximal embrasure and papilla shape to assist in determining tooth shape QuickTi me™ and a T IFF (Uncompressed) decompressor are needed to see thi s pi cture. QuickTi me™ and a T IFF (Uncompressed) decompressor are needed to see thi s pi cture. Shade Selection • Portrait shade guide • Use existing teeth as a guide – Shade B2 is close an average shade – Top number (A, B, C, D) on tabs corresponds to Vita porcelain shade – Bottom number (P) is Portrait # for ordering Shade Selection • Don’t show all shades to patient • Patients will pick the whitest • Show 2 or 3 shades under lip – Colour perception affected by background QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Check Shade Against the Patients Face • • • • Check shade of existing denture Ask if patient wants same shade or change Allow patient to view shade against lip with mirror Obtain patient approval Squint Test • Check for value (brightness) • Squinting reduces the influence of hue • If the teeth look too bright while squinting, suggest something less bright Shade Selection • Teeth darken with age • Correlation with skin and hair colour is suspect • Vita ‘C’ shades are greyish Patient Chooses Shade with Input from Dentist • Patient – owns the dentures – will look at them every day • Offer your opinion, don’t persuade Disinfect Shade Tabs Denture Tooth Material • Porcelain teeth less common now • Acrylic easier to set and adjust – Last life of denture (5-7 years) Denture Tooth Material Porcelain Less wear More translucent Brittle - fracture easily Don’t bond to base (stain, fall out) Difficult to set, adjust Acrylic New acrylics wear better Improved translucency with layers More resilient - Less breakage Chemically bonds to base Quieter Easier to set/adjust Gum sticks Selecting Posterior Tooth Form Anatomic Teeth (10°, 20°, 30°, 40°) • Use for patients with: – Esthetic concerns – Coordinated jaw movements – Denture opposing natural teeth 10° 20° 30° Non-Anatomic Teeth (0°, Rational, Monoline, etc.) • • • • Jaw size discrepancies (Class III) Severe ridge resorption Uncoordinated jaw movements Poorer esthetics, due to lack of cuspal inclines Non-Anatomic Teeth • No overbite • Normal overjet (1-2mm) No tooth form has been proven most efficient - most patient can’t discern a difference Posterior Tooth Selection • Match size & shade to anteriors • Determine distance from distal of canine to ascending ramus (29, 30 mm, etc.) Posterior Tooth Selection • Buccolingual size can affect the tongue space – smaller teeth if tongue space is limited Prescribing Denture Teeth ¯ Use paper mould guides ¯ Infection control Prescribing Denture Teeth • Dentsply Trubyte Portrait – Acrylic Teeth – Layers of acrylic - improved translucency – IPN - improved wear resistance Summary • Selecting denture teeth – advise patient don’t persuade – an art, minimal science – use common sense – use old denture as a starting point – look at dentate patient esthetics – Seminar exercise Seminar Exercise • Work in pairs in seminar groups • Select shade for partners • Use maxillary cast and Boley gauge to select tooth mold that best approximates partner • Select corresponding mold for mand. teeth • Complete prescription for teeth • Have faculty seminar leader check & sign