CLEAR PLASTIC THERMOFORMED TYPE RETAINERS VS FIXED BONDED WIRE RETAINERS:

Hugo orthodontics only use fixed retainers in the lower arch because the lower teeth bite onto the upper fixed retainers if there is a correct relationship of lower to upper incisors, damaging the fixed retainer and or the lower teeth.

Adequate vertical overlap of the incisors is necessary for incisor guidance during chewing, without which there is an increased risk of non-working interferences and temporo-mandibular joint dysfunction (TMD).

Inadequate vertical overlap of the incisors or large upper incisors does allow an upper splint, but there is also an aesthetic price to pay.

Insufficient vertical overlap of the incisors often doesn’t allow for the most aesthetic placement of the upper incisors, resulting in a straight-across or reverse smile instead of the correct smile arc.

Fixed retainers are never fitted for any length of time in patients with inadequate hygiene, as the presence of the fixed retainer very significantly enhances the risk of decay and gum disease and it is an impediment to excellent brushing and flossing.

A lower fixed retainer is routinely fitted for a year or two in cases treated to completion with fixed appliances, where there was significant lower crowding, if there is good oral hygiene (reference link)

However, fixed retainers even in the lower are not an acceptable long term solution. Long term use of fixed retainers can result in very unpleasant side effects (Am J Orthod Dentofacial Orthop 2017;151:1027-33).

Clear plastic retainers are the best form of retention as they can be worn progressively less over time and always allow for excellent hygiene.

Clear plastic (Invisible retainers) also help to protect the teeth and temporo-mandibular joints from damage due to bruxing.