MARPE - SARPE: Sense and NON-sense Björn Ludwig

Join me for a summary of Björn Ludwig’s lecture exploring Miniscrew Assisted Rapid Palatal Expansion (MARPE) and Surgically Assisted Rapid Palatal Expansion (SARPE). Björn described how MARPE works, aspects of design and his clinical process.

Effects of MARPE
Parallel opening of suture 2mm greater at 6 region than RME (S/R Krusi 2019)
Facial changes
Widens Zygoma
Nasal base expands
Changes to the orbit – no significant but beware Brutally evasive!
No periodontal side effects with MARPE (limited evidence) S/R Vidalon 2021
RME Vs bone borne, hybrid = bone borne no dental side effects: Canan 2017

Age
MARPE Vs RME
Age up to 11, no difference in outcomes Bazargani 2021


Retention after MARPE
At 7 months: suture has not fully remodelled
Retention is needed for 1 year to allow full remodelling
Type of retainer
TPA does not maintain bony changes Prado 2014
TPA with TADs = prevent bony relapse

Expansion rate of MARPE
Fast Vs slow bone borne
Fast (2-3 x activation per day) Vs slow (2 activations per week)
Slow expansion MARPE: Sutural opening still occurs Pulver 2016 (Rabbit study)
No diastema


Activation process: Force controlled polycyclic activation
Activation occurs if the force is 500g, key indicates activation Winsauer 2021

Airflow
Increase in airflow with MARPE
White paper from AJODO on OSA – limited evidence
Our job is to get rid of crossbites NOT to resolve OSA
MARPE effective at resolving crossbite S/R: Kapetanović 2019
MSE reduce OSA: Brunetto and Moon 2022
Björn considered a good side effect, not the main cause


Class 3
RME most effective in class 3 cases
Alt-Ramec Eric Liou 2005
3 x day = maxilla moves downwards and forwards due to position of buttress
Facemask
Facemask in the night, and class 3 elastics in the day
A point advance 3mm: MARPE + facemask study: Maino 2018
Realistic ½ unit correction – borderline correction

SARPE Vs MARPE
SARPE mainly changes maxilla, maintains aspects of midface
MARPE changes to midface

Design features
Arms to 1st molars Vs no arms
Arms prevent distal rotational movement when activate MARPE
Additional screws no difference 4 or 6 Winsauer 2013

Position of screws
Posterior screws reduce rotation
BUT very thin bone, penetrate nasal base but of little consequence as the floor of the sinus lifts 1-2mm (6-7mm then signs of perforation)
Posterior TADs do allow for bicortical engagement (Moon)
Placement at an angle distally around 6 region (towards teeth)
Björn states limited use for anchorage posterior palate, main use prevent distal rotation
Design type
MSE Vs power screw
Björn considers the argument not as important as the practicality, main features are:
The TAD used
Abutment connecting TAD to expander
Expansion screw type

Insertion guide
Biocompatible material Formlabs Surgical Guide Resin
Individual guide Vs stock
Stock: Slight deviation between clinical insertion Vs planned insertion
Tip : MARPE plan to have lab open screw by 5 turns so it can be adapted chairside by opening / closing
Contra-angle Vs straight insertion:
Contra-angle preferred as less opening required when factor screw and insertion plate

Weak point in design
Failure can occur between abutment (housing for screw) and expander
Forces high (5-10N 1kg scary high) - the weakest aspect
Björn recommends laser welding or 1 piece metal printing (Andre Walter 2017)

Planning
Digital planning
After planned insertion of tads
Assemble abutments, screw – power screw, design arms
Digital planning to allow adaptation of hybrid, MSE – Pirate style!
Tip: 2 arms to 6s to prevent tipping


Delivery
1 appointment to place screws and expander
Insertion TADs 60rpm
Secure with floss – 2 have been swallowed (with Björn)
Secure expander with fixation screw
Start activation – Bond up lower arch same time to decompensate


Take home messages
Hi tech is good but low tech is key
No body said it was easy, and orthodontics is not easy



For more information see Benedict Wilmes guest blog on Kevin O’Brien’s Orthodontic Blog