Page 138 - FINAL COMPENDIUM 2020-2021 27.2.2022

MICROBIAL ADHERENCE ON VACUUM FORMED RETAINERS WITH DIFFERENT SURFACE
ROUGHNESS AS CONSTRUCTED ON CONVENTIONAL MODELS AND 3D RECONSTRUCTED
MODELS: A RANDOMISED CONTROLLED CLINICAL TRIAL
Belayutham S, Wan Nurazreena WH, Fathilah AR

Objective: To determine the association between microbial adherence on vacuum formed
retainers (VFRs) with different surface roughness as constructed on conventional and
three-dimensional reconstructed models. Materials and methods: Patients on fixed
appliances at the Faculty of Dentistry, University of Malaya and ready for debond were
invited to participate in this single centre randomised controlled trial. Subjects were
allocated to three interventional groups (VFRs fabricated on conventional, fused
deposition modelling (FDM) or stereolithography apparatus (SLA) working models) using
block randomization with stratification for gender. Subjects wore the interventional VFRs
for three months full time, followed by another three months of part time wear. The
interventional VFRs were collected after each time frame for the analysis of the microbial
adherence. Surface roughness of VFRs were indirectly measured on the working models.
Results: Analysis included 30 subjects, after 6 subjects dropped out. Microbial adherence
between VFRs fabricated on conventional and 3D reconstructed models was not
significantly different. Microbial adherence on the lower VFRs was significantly higher
than the upper VFRs during both retention regime. There were no significant differences
in microbial adherence on VFRs between full time wear and part time wear. Mean surface
roughness was significantly different between the groups where SLA had the smoothest
surface. There was no association between surface roughness and microbial adherence.
Conclusion: Microbial adherence on VFRs was not associated with surface roughness of
VFRs. VFRs made conventionally and on 3D reconstructed working models can be used
without potentially having higher microbial adherence-related risk to the oral health over
each other. While lower VFRs are more prone to microbial adhesion, thus potentially
risking the oral health in the lower arch.

Keywords: Microbial count, Vacuum formed retainers, Surface roughness, Stone models, 3D
printed models, Fused deposition modelling, Stereolithography apparatus

th
Presented at the APAC Orthodontic Postgraduate Forum EMERGE’ 21 (SEA Regional Round) on 18 July 2021 and 14 Dental
Postgraduate Conference University of Malaya on 23 September 2021
Dr Sonia Belayutham
Orthodontic Unit
Mak Mandin Dental Clinic
Seberang Perai Utara
Penang

AP Dr Wan Nurazreena Wan Hassan
Department of Paediatric Dentistry & Orthodontics
University of Malaya
Kuala Lumpur

Prof. Dr Fathilah Abdul Razak
Department of Oral & Craniofacial Sciences
University of Malaya
Kuala Lumpur

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