Posterior Tooth Selection Dr Muhammad Rizwan Memon FCPS

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Posterior Tooth Selection Dr Muhammad Rizwan Memon FCPS Assistant Professor

Posterior Tooth Selection Dr Muhammad Rizwan Memon FCPS Assistant Professor

1 st Step (Buccolingual Width) • Should be less than the width of natural

1 st Step (Buccolingual Width) • Should be less than the width of natural teeth – Why: 1. Amount of stress reduced 2. It allows sloping of flanges towards occlusal table 3. Helps in denture stability 4. Neutralization of forces 5. Sufficient Tongue space

2 nd Step (Mesiodistal Length) • Mandibular Arch: Space between distal of canine to

2 nd Step (Mesiodistal Length) • Mandibular Arch: Space between distal of canine to the beginning of retromolar pad, Posterior teeth are not placed on inclined plane of retromolar pad • Maxillary Arch: Space between distal of canine to the maxillary tuberosity • Available space will dictate whether three or four posterior teeth are used • Arrangement of three posterior teeth is more often the standard & will reduce the potential for the placement of the second molar too far posteriorly. Posterior teeth that extends too close to the posterior border of maxillary denture may cause cheek biting

3 rd Step (Vertical Height) • Vertical height should correspond to the available Inter-arch

3 rd Step (Vertical Height) • Vertical height should correspond to the available Inter-arch space and height of anterior teeth • Height of maxillary 1 st premolar should be comparable to that of maxillary canine for proper esthetic effect • Longer teeth can be selected for a older individuals if more tooth exposure is indicated that mimic gingival recession

4 th Step (Type of Material) • • • Porcelain teeth Acrylic teeth Composite

4 th Step (Type of Material) • • • Porcelain teeth Acrylic teeth Composite Resin teeth Acrylic teeth with amalgam inserts Acrylic teeth with cast gold occlusal surfaces

Porcelain Teeth • INDICATIONS: – When superior esthetic is required – When there is

Porcelain Teeth • INDICATIONS: – When superior esthetic is required – When there is sufficient inter-arch space available – Well formed ridges • ADVANTAGES: • • • Very esthetic Does not wear easily Does not Stains & discolors with time Maintains masticating efficiency for years DISADVANTAGES: • • Expensive Difficult to grind & adjust Requires adequate inter-arch distance Abrades or chips opposing natural teeth & gold crowns Does not Bond chemically to denture base Clicking impact sound Brittle

Acrylic Teeth • Most commonly used tooth material for complete dentures • INDICATIONS: –

Acrylic Teeth • Most commonly used tooth material for complete dentures • INDICATIONS: – – • ADVANTAGES: • • When there is opposing natural dentition. When opposing dentition has got the gold crowns or inlays. Where there is reduced inter-arch space In RPD. Inexpensive & easily available Easy to grind & adjust Absorb the occlusal stresses Does not wear the opposing natural teeth. Bond chemically to denture base. . Softer impact sound DISADVANTAGES: • • • Wear easily Loss of VD because of wear Stains & discolors with time

Acrylic Teeth with Amalgam Inserts • INDICATIONS: – In Resin teeth opposing porcelain teeth

Acrylic Teeth with Amalgam Inserts • INDICATIONS: – In Resin teeth opposing porcelain teeth to reduce wear

Acrylic Teeth with Cast Gold Occlusal Surfaces • INDICATIONS: – When opposed by natural

Acrylic Teeth with Cast Gold Occlusal Surfaces • INDICATIONS: – When opposed by natural teeth – When opposed by gold occlusal surfaces – When opposing porcelain teeth

5 th Step (Cusp Inclines) • Based on cuspal morphology the posterior teeth may

5 th Step (Cusp Inclines) • Based on cuspal morphology the posterior teeth may be classified as: – 20 0 r 30 degree cusped teeth (Anatomic) – Monoplane (o-degree teeth/non-anatomic) – Flat teeth with compensating curves – Lingualized occlusion or combinations

20 0 r 30 Degree Cusped Teeth (Anatomic Teeth) • INDICATIONS: • Good ridge

20 0 r 30 Degree Cusped Teeth (Anatomic Teeth) • INDICATIONS: • Good ridge form with sufficient retention & support. • Where balanced occlusion is planed. • Where possible to record & transfer the centric relation with accuracy. • ADVANTAGES: • • Easier to balance Better masticatory efficiency Reduced chewing cycles Better esthetics • DISADVANTAGES: • Restriction of occlusal movements from centric to eccentric jaw positions. • Lateral forces can destabilized the denture.

Monoplane (0 -Degree/Non-Anatomic Teeth) • INDICATIONS: n n • ADVANTAGES: n n n •

Monoplane (0 -Degree/Non-Anatomic Teeth) • INDICATIONS: n n • ADVANTAGES: n n n • Flat ridge cases Abnormal jaw relation case Where difficulty is faced in recording the centric relation. Where balanced occlusion is not planed. Freedom of occlusal movements from centric to eccentric jaw positions. Elimination of lateral forces that can destabilized the denture. When denture settling take place due to denture abuse no cuspal interference occur. DISADVANTAGES: q q q Not esthetically pleasing. Difficult to balance Reduced masticatory efficiency