Occlusion

Question 1

why do you need to record the occlusion?

Answer 1

need to know the position of the teeth in relation to each other, need to know what is normal for the patient and keep it the same, planning to change occlusion, facilitate denture design, ensure loading forces applied correctly to teeth and underlying mucosa/bone, help the technician set up the teeth, ensure the denture is stable and not dislodged in function

Question 2

when can you record the occlusion?

Answer 2

primary registration, secondary registration, framework registration

Question 3

why do you record the occlusion at the primary registration stage?

Answer 3

examine occlusion, facilitate denture design, mount surveyed casts, position denture components without occlusal interference

Question 4

why do you record the occlusion at the secondary registration stage?

Answer 4

to accurately mount casts prior to framework construction, primary reg incorrect, plan to change occlusion, case is complex with extended edentulous spaces, replace anterior teeth

Question 5

why do you record occlusion at the framework trial stage?

Answer 5

no primary reg, accurately mount the master casts, replace multiple anterior teeth, plan to change occlusion, error with previous reg, extended edentulous spaces

Question 6

what is the aim of the occlusion visit?

Answer 6

to inform the technician where you want the artificial teeth to be positioned, their shade and mould together with information on how the teeth occlude

Question 7

what do you establish on an occlusion visit?

Answer 7

inter-occlusal relationship to articulate casts, OVD, buccal/labial contours of wax record block, tooth shade and mould

Question 8

what is the procedure outline for recording occlusion?

Answer 8

disinfect record blocks, bowl of cold water to chill record blocks to avoid distortion, record OVD with willis bite gauge or dividers in the ICP, adjust the blocks by using a bunsen flame to heat a palette knife to reduce height and buccal surfaces, join blocks together using pink or wax registration paste, disinfect casts and record blocks

Question 9

how do you record the OVD using the two dot measure?

Answer 9

choose point on nose and chin with minimal movement, teeth in ICP, use dividers to measure distance between dots, distance between divider arms = OVD (measured with ruler)

Question 10

how do you measure OVD with a willis bite gauge?

Answer 10

teeth in ICP, fixed arm nasio-labial position, sliding under chin, distance between sliding and fixed arms = OVD

Question 11

how do you record the RVD (resting vertical dimension) with the two dot method

Answer 11

choose point on nose and chin with minimal movement, jaw relaxed lips just touching, space between posterior teeth, use dividers to measure distance between dots, distance between divider arms = RVD

Question 12

how do you record the RVD using the willis bite gauge?

Answer 12

jaw relaxed lips touching space between posterior teeth, fixed arm nasio-labial position, sliding arm under chin, distance between sliding and fixed arms = RVD

Question 13

how do you calculate the freeway space?

Answer 13

RVD-OVD

Question 14

what is freeway space

Answer 14

the space between the occluding surfaces of the maxillary and mandibular teeth when the mandible is in physiologic resting position

Question 15

how do you adjust the blocks?

Answer 15

try in one at a time, block must stay in place, use wax knife and hot plate/spatula to adjust, adjust upper rim first, may need to adjust the occlusal, buccal and lingual/palatal of the blocks

Question 16

what problems cause displacement of the record blocks?

Answer 16

overextension of the peripheries which cause a block to drop/displace, too much lip support will make it drop

Question 17

what do reference points help you to adjust?

Answer 17

buccal/labial and occlusal contour of the record blocks

Question 18

what are the reference points on the face to use when adjusting record blocks?

Answer 18

teeth present, dento-facial midline, inter-pupillary line, ala-tragus line, curvature of lower lip, smile line, gingival margins of existing anterior teeth, previous dentures

Question 19

what reference point do you use as a guide if multiple posterior teeth are missing?

Answer 19

ala tragus line

Question 20

what is the ala-tragus line used for?

Answer 20

as a guide to the position of the occlusal plane

Question 21

when is the dento-facial midline most relevant?

Answer 21

when there are multiple missing anterior teeth

Question 22

what does the interpupillary line guide you with?

Answer 22

where your upper incisal plane should be

Question 23

what should the incisal plane follow?

Answer 23

the curvature of the lower lip or that of teeth already present

Question 24

where do you trim the wax rims to in relation to the occlusal plane?

Answer 24

so that it is appropriately orientated in relation to the remaining natural teeth

Question 25

what does foxes occlusal plane guide do?

Answer 25

help to recreate occlusal and incisal planes on a record block when extended edentulous spaces

Question 26

how do you adjust upper blocks?

Answer 26

occlusal and incisal plane must be appropriately orientated in relation to remaining upper natural teeth, for anterior saddle ensure that the rim indicates the appropriate incisal level and lip support, check occlusal stop when patient occludes with upper rim in place, if tooth surfaces have been separated then trim rim under occlusal contact established

Question 27

how do you adjust lower record blocks?

Answer 27

trim lower rim until occlusal stop has been established, add or remove wax from buccal and lingual surfaces of rims until centre of the rim lies over the lower ridge and is the same width as the replacement teeth, upper rim should then be harmonised with the lower rim in accordance with the skeletal relationship

Question 28

how do you register the occlusion?

Answer 28

modify rims ensuring that there is small space between occlusal surface of rim and all opposing teeth or rim, record position of maximum intercuspation using registration material, occlude casts using the occlusal rims and check that the tooth relationship on the casts is the same as in mouth, if premature contact between the heels of cast and opposing rim then eliminate it

Question 29

what do you do for an extended anterior saddle?

Answer 29

make sure index teeth in occlusion, mark centreline, mark canine positions if missing, mark high smile line

Question 30

what do you use to select shade of teeth?

Answer 30

existing teeth, previous denture, patient preference

Question 31

what do you use to select mould of teeth?

Answer 31

existing teeth, previous denture, measure

Question 32

what instructions do you give to the lab after this stage?

Answer 32

what to articulate the casts on - average value is fine, set teeth for wax trial