ROYAL LONDON SPACE ANALYSIS

Question 1

• London Space Analyisis?

Answer 1

• Undertaken once an in depth clinical & cephalometric analyses have been undertaken.
• Based on the theory of Andrews 6 Keys
• Aims to quantify space requirement in each arch to attain the outlined treatment objectives AND to quantify the space implications of treatment mechanics
• 2 STAGE process
  
  • Stage 1: Assessmen tof space requirement
  • Stage 2: Assessmen to fany additional space created or used during treatment.

Question 2

• In the RLSA measurements are taken in which unit and to which value

Answer 2

• Nearest mm or at times nearest 1/2 mm
• +ve = space is present or created
• -ve = crowding or when space is required

Question 3

• Which 6 specific aspects of the occlusion are assessed in the RLSA? (Stage 1)

Answer 3

• Crowding & spacing
• Levelling COS
• Arch expansion & contraction
• Incisor AP change
• Angulation ( applies only to MX incisors)
• Inclination ( applies only to MX incisors)

Question 4

• Crowding and spacing RLSA

Answer 4

• Measured anterior to M surface of 6’s.
• Assessed in relation to most representative archform ( the incisors used for this must be used consistently throughout remaining assessment).
• Clear ruler ( occl or labially) measuring width of misaligned teeth and space available.

Question 5

• In the RLSA how much space is accounted for if the UE’s are presnt and if the LE’s are still present ?

Answer 5

• UE’s= +1 MM
• LE’s= +2mm

Question 6

• RLSA LEVELLING COS ?

Answer 6

• Measure vertical height from PM cusps to a horizontal plane extending from the DISTAL cusps of L6’s to incisal edges.
• Only measure if the PM’s have not already been accounted for in the assessment of crowding.
  
  • Only 1 value is allocated to each arch.

DEPTH OF COS (MM) SPACE REQUIRED (MM)

3 1

4 1.5

5 2

Question 7

• How much space is need for a 3mm COS

Answer 7

• 1MM

Question 8

• How much space is needed to flatten a 4 mm COS

Answer 8

• 1.5MM

Question 9

• How much space is needed to correct a 5 mm COS

Answer 9

• 2MM

Question 10

• Arch expansion RLSA ?

Answer 10

• Not counted if you are planning the buccal.lingual movement of an individual tooth as this would have already been assessed in the crowding assessment.
• For every 1mm expansion of the intermolar width = 0.5mm space.

Question 11

• RLSA INCISOR AP CHANGE ?

Answer 11

• First assess if the position of the LINC is to be altered.
• If yes to then correct the UINC so that an OJ 2-3mm is achieved.
• Make sure the same incisor is used throughout al of the assessment.
• 1mm Incisor advancement = +2mm space
• 1mm incisor retraction= - 2mm

Question 12

• RLSA, INLCINATION ( TORQUE) ?

Answer 12

• Applies ONLY to max upper incisors
• 1mm of space needed for every 5 degrees of retraction of ALL 4 UINCS
• 0.5MM sp needed if only 2 Uincs are retracted

Question 13

• In the RLSA which 3 components of the analysis have the most influence on space implications ?

Answer 13

• Crowding and spacing
• Arch width change
• Incisor AP change

Question 14

• In the RLSA Class I molar relationship is associated with what kind of space requirements in the upper and lower arches ?

Answer 14

• Space requiremen is equal in both upper and lower arches.
• UNLESS THERE IS A TOOTH DISCREPANCY!!

Question 15

• Assuming 7mm premolars, bilateral FULL UNIT CLASS II molar relationship are associated with what pattern of space requirement ?

Answer 15

• Upper space requirement of -14mm THAN the LOWER arch.
• If it was only a -7mm space requirement then it would indicate a 1/2 unit Class II molar relationship.

Question 16

• What measurements are undertaken in the second stage of the RLSA ?

Answer 16

• Additional space to be created or used DURING TREATMENT.

Question 17

• What are the components for the assessment of additonal space creation and used in the RLSA?

Answer 17

• Tooth reduction and enlargement
• Extractions
• Absent teeth
• Distal and mesial molar movement
• Differential maxillar and madibular growth

Question 18

• Tooth reduction and elargement ( RLSA)

Answer 18

• Individual teeth of incorrect size in relation to other teeth. e.g. Small lateral incisors- May not appear to present any problems for ALIGNEMENT.
• BUT.. good occlusion can only be achieved when the amount of tooth material in both arches is in proportion.
• THEREFORE NEED TO MEASURE HOW BIG YOUR GOING TO MAKE THESE TEETH AND HOW MUCH SP YOU NEED TO DO THIS.
• Conversely space is gained from reducing the MD width if unusaly broad teeth by IPR.

Question 19

• EXTRACTIONS ( RLSA)

Answer 19

• Space gained by extractions is NOT entirely available for relief of crowding UNLESS the POSTERIOR teeth are prevented from moving mesially.
• Where NO Anchorage Reinforcement is used the net space available is determined by several factors:
  
  • Which teeth are extracted
  • WHICH ARCH IS CONSIDERED ( gr8r tendency for mesial movement of the upper molar in the upper arch)
  • WHETHER SECOND MOLARS ARE BANDED (reinforces anchorage).
  • Whether the crowding is located anteriorly or in the buccal segments.
  • The degree of incisor crowding and therefore the amount of canine retraction
  • The angulation and inclination changes needed MESIAL of the extraction spaces.
  • The angulation of teeth distal to the extraction spaces.

Question 20

• IF NO ANCHORAGE REINFORCEMENT IS USED AND 4’S ARE EXTRACTED HOW MUCH SPACE WOULD BE AVAILABLE FOR THE LABIAL SEGMENTS ?

Answer 20

• 40%- 65% OF FIRST PM SPACE WILL BE AVAILABLE FOR THE BENEFIT OF THE LABIAL SEGMENT.
• THIS REDUCES TO 25% - 50 % FOR SECOND PREMOLARS.
• THE NET SPACE AVAILABLE IS LESS IN THE UPPER ARCH THAN THE LOWER ARCH, AS MESIAL MOVEMENT OF MOLARS OCCURS TO A GREATER EXTENT THAN IN THE LOWER ARCH.

Question 21

What is the significance of a Residual Space measure ment of having a value of zero at the end of analysis?

Answer 21

If the aims of treatment /mechanics are reasible then at the end of analysis there should be ZERO residual space.