Tooth Bone vs Tissue Bone MSE Does it matter? Beom Kim. AAO June 2021. Episode 120

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Farooq Ahmed

Tooth Bone vs Tissue Bone MSE Does it matter? Beom Kim


Reasons for Bone borne expansion

·      Opening mid-palatal suture in adults

·      Success OVERALL 74-90%

o   Study of success rates of palatal suture opening depending on age Oliveiera 2021

§  15-19 82%

§  20-29 82%

§  30-37 20%


Challenge – older male patients


Conventional RME in adults – risks

·      Periodontal problems

·      Severe tipping

·      Root resorption


Types of skeletal Anchorage Maxillary Expansion SAME

1.     Hybrid – TAD and attachment to teeth

2.     Bone bourne – no contact with teeth


Which is better

·      Stress of dentition with both types Finite analysis Lee 2014

·      BB significant less stress on the buccal plate, however hybrid stress on buccal plate Seong 2018

·      Comparison of RME, hybrid and BB Oh 2019

o   Suture opening at ANS: greater with hybrid 4.5mm, BB 2.8mm, RMA 1.2

o   Molar expansion: Greater with yybrid 6.3mm, RME 5.1, bb 3.5

o   Molar tipping: Greater with RME 4 degrees, Hybrid and BB 2 degrees

·      BB Vs RME Lin 2015

o   Skeletal expansion: BB 1mm more than RME

o   Molar tipping: BB less tipping 3 degrees

·      4 banded RME Vs 2 band hybrid appliance Toklu 2015

o   Molar expansion: No difference

o   Bone bending at 6s

§   3 degrees = no difference RME Vs hybrid

o   Molar tipping = no difference

o   1st premolar tipping = RME 2.5 degrees Vs 0.5 hybrid

·      Hybrid Vs RME Jai 2021

o   Skeletal opening: Greater with hybrid  (3.8mm Vs 2.3mm)

o   Molar expansion: No difference (RME 7mm Vs 6.3mm hybrid)

o   Molar tipping: Hybrid less tipping  (6.7 degrees Vs 3.8)

·      BB Vs RME Celank-Koca 2019

o   Molar expansion: No difference (4.2 RME Vs 4.5 BB)

o   Sutural opening: BB greater (3.1 BB Vs 1.1 RME)

·      Arruda / Kim study BB Vs Hybrid

o   Expansion dental Vs Skeletal = 40%


Overall changes


·      RME Jai 2021

o   Expansion dental = 7mm (6-6)

o   Skeletal changes 2.2mm (6-6)

§  Ratio skeletal:dental = 31%

o   Tipping 5-6 degrees of molars

·      Hybrid Moon 2020

o   Expansion dental 5mm

o   Skeletal expansion 2.45

§  Ratio skeletal: dental 50% (OTHER studies 28%)

o   Tipping 2.4 degrees

·      BB Lin 2015

o   Expansion 3.4mm

o   Skeletal 1.87mm

§  Ratio skeletal:dental 54%

o   Tipping 1.15


Difference in changes possibly due to number of TADs, technique


Systematic review BB Vs RME Crusi 2019

·      Conclusion

o   No difference in dental expansion

o   BB greater skeletal expansion = 2mm greater (6-6 level)

o   Hybrid = less tipping than RME


Clinical questions to ask when expanding


What is the purpose of expansion?

·      Correct crossbite OR expand midface


End point of expansion?

·      Molar correction

·      Achieving skeletal expansion = for 2mm require 5mm dental expansion


Limitations = studies based on younger patients


Adult patients with MSE Kangvonkit

·      Skeletal expansion 4.6mm

·      Soft tissue changes

o   Alar base increased 2mm


Issues with skeletal expansion

·      Different vertical heights of TADs = asymmetric expansion

·      30% of skeletal expansion = asymmetric Kim 2019

o   Issue is up to 2mm of vertical discrepancy also occurs = Cant


How to manage cases

·      Normal molar angle + thin alveolar bone

o   BB – maximise skeletal changes

·      Normal molar angle + normal bone

o   Hybrid / BB

·      Tipped molars

o   BB

·      Palatally tipped molars

o   RME, hybrid, BB


Does it matter

·      Younger patients = probably not

·      Adult patients = consider skeletal anchorage



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