Setting teeth for RPDs

Question 1

what is the aim when setting teeth?

Answer 1

• complement the existing teeth
• restore the arch
• aesthetics
• function

Question 2

what materials can artificial teeth be made from?

Answer 2

• acrylic
• porcelain

Question 3

what are the properties of acrylic teeth?

Answer 3

• chemical bond with denture base
• natural appearance and silent during function
• tough
• soft-low abrasion resistance
• easily trimmed and polished/customised
• cold flow under pressure
• insoluble in mouth fluids - somee dimensional change

Question 4

what are the properties of porcelain teeth?

Answer 4

• mechanical attachment with denture base
• natural appearance and possible noise
• brittle
• friable - grinding removes surface glaze
• hard-ish resistance to abrasion
• inert in mouth fluids - no dimensional change
• high heat deformation - no permanent deformation under mastication forces

Question 5

what are the properties of modified acrylic/composite/polymers?

Answer 5

• chemical bond with denture base
• partial bonding - recommended mechanical/bonding agent
• higher abrasion resistance

Question 6

how are porcelain teeth mechanically bonded to the denture?

Answer 6

• anterior teeth have a metal retention pin
• posterior teeth have a hollowed area for the denture base material to flow through

Question 7

what are the different tooth shapes for anterior teeth?

Answer 7

• oval
• square
• tapered

Question 8

how do you adjust teeth moulds?

Answer 8

• remove material from the ridge lap
• do not remove from the incisal tip as it can change tooth shape

Question 9

what is a disadvantage of adjusting tooth moulds?

Answer 9

• can affect the denture base and tooth bond
• the more of the ridge lap that is removed, the less bonding area available and can be more easily de-bonded

Question 10

what is incorrect about this picture?

Answer 10

the lateral is overlapping the central outside the arch - it is placed labial to the arch

Question 11

what is incorrect about this picture?

Answer 11

the central incisor is protruding beyond the natural tooth

Question 12

what is incorrect about this picture?

Answer 12

the lateral has been trimmed too much and is not in harmony with the central or canine

Question 13

describe the denture base that the trial denture with teeth is trialled

Answer 13

• it is a temporary base that will be discarded at the processing stage
• usually made from light-cured acrylic or shellac
• used to establish tooth position / finishing lines may be used for CoCr

Question 13

what is natural tooth guidance? how can you check it?

Answer 13

• the way natural teeth guide the jaw’s movements during chewing, swallowing, and speech
• artificial teeth must conform to existing tooth surface wear and should follow natural tooth guidance
• check using canine guidance or group function

Question 14

how do you provide symmetry to the appearance of anterior teeth?

Answer 14

• set teeth to the **long axis **of the corresponding tooth
• contact points should also correspond to the natural dentition
• use long axis of teeth to provide a mirror image of arch

Question 15

how can you refine tooth setting?

Answer 15

final adjustments to tooth length should be adjusted chairside if the denture is not tooth supported