The Way Forward Part 2: Orthodontic Treatment Considerations

Bonding

The need to polish the enamel surface with pumice and the constant use of a three-way syringe for rinsing make conventional bonding an aerosol-generating procedure (AGP). Many non-AGP options for bonding are available (although it must be emphasized that these can compromise bond strengths^58,59):

• Light-cured resin-modified glass ionomer cement can be used without any prior enamel preparation such as polishing, etching, or drying. This option reduces the need for an absolutely dry field, in turn reducing the need for any AGP.⁶⁰
• Self-etch primers can also be used without prior enamel preparation and etching, but they require the smear layer to be removed prior to use, usually by pumicing or polishing teeth, which would be unnecessary with an AGP.
• The need for a three-way syringe before or after polishing and etching can be avoided by using a dry cotton roll to clean the enamel surface. Suction can still be used because it is non-AGP. Paul Gange Jr. of Reliance Orthodontic Products has shared similar interim recommendations for non-aerosol bonding.⁶¹

Indirect bonding may be another alternative to conventional direct-bonding techniques because it reduces patient exposure. It should be kept in mind that flash removal for indirect bonding is an AGP and must be performed with utmost caution.⁶²

Leveling and Alignment

Leveling and alignment are complex processes during which all teeth move in different directions at the same time. As the teeth level and align, reciprocal forces develop between them and help guide the teeth to the correct positions. Practitioners usually start with light forces and round, light-gauge nickel titanium wires, which have a considerable amount of play that can cause slippage of the wire from brackets, especially on the terminal molars. Square or rectangular nickel titanium wires are preferable to avoid emergencies caused by slippage. Additionally, the archwires can be cinched back to prevent the sharp ends from impinging on the gums. The use of flowable composite is also recommended. To avoid slippage, it is wise not to include the second molars during the first few visits; they can be incorporated during the stages employing flexible rectangular wires.

Deep Bites

It is a common practice to use a reverse-curve nickel titanium wire to correct a deep bite caused by a deep curve of Spee in the lower arch. It usually takes about three months to flatten the curve with a constant force of approximately 300g generated by the wire itself. Note that such high forces from non-self-limiting mechanisms, if left unmitigated or not regularly attended, may yield untoward iatrogenic effects such as excessive bite opening or proclination of the lower incisors (Fig. 16).⁶³

Ligation and Bite Blocks

Archwires should be tied to the brackets with stainless steel ligatures instead of elastomeric rings, since the metal ligatures are more hygienic and offer more robust ligation. Passive self-ligating brackets offer advantages in delayed appointment situations, including fewer emergencies associated with torn or loose elastomeric rings or oral hygiene concerns caused by food and plaque accumulation around elastomeric rings.⁶⁴ The first few appointments for patients during the leveling and alignment phase can therefore be scheduled about 10 weeks apart to reduce patient exposure and risks.

The use of anterior and posterior bite blocks to avoid premature contact of brackets during the initial stages must be carefully monitored. Such bite raisers are generally used for one to two months, until the teeth are marginally aligned and there is no premature contact that could lead to bracket “pop-outs.” If a patient fails to return for an appointment, however, there is a chance that the occlusal plane could be altered by reciprocal extrusion of the non-contacting teeth or intrusion of the contacting teeth (Fig. 18).

Extractions and Expansion

Orthodontic extractions may be carried out with standard precautions, but they should be planned for a single visit to reduce patient exposure. Meticulous planning for orthodontic anchorage is essential prior to extractions. Be aware that if there is a COVID-19 return and a lockdown is reimposed, further measures may be required to avoid undesirable anchorage loss.

Expansion treatment is still possible, but only with close monitoring after the practice reopens. Patients must be clearly instructed regarding the objectives of expansion. Once rapid palatal expansion is complete, it is essential to retain the achieved results by recalling the patient as soon as possible in case of a future lockdown. Overactivation can cause undesirable buccal tipping of posterior teeth, potentially necessitating “round-
tripping” and creating delays in finishing (Fig. 19).

Alternative methods of slow expansion are preferable during this period because they are more fail-safe and do not create abrupt changes over short intervals, thus reducing the chance of emergencies.

Any movements that generate higher moments, such as 3rd-order twists, should be postponed for a few months. Unmonitored overexpression of these tooth movements can predispose to root resorption, fenestration, or dehiscence.

Retention

Finishing and polishing should be performed with caution during the debonding appointment because they are AGP. An Essix^‡‡ or other removable retainer is preferable over a bonded retainer to avoid unnecessary aerosol contamination. Removable retainers can be worn for three to six months, after which fixed retainers can be bonded if indicated. Providing patients with additional sets of removable retainers may be a good policy in case one is lost or damaged during a potential COVID-19 resurgence.

Functional Appliances

Patients using removable functional appliances can be monitored remotely through video conferencing, and appliance use can be tapered once the objectives are met. In case of a second COVID-19 outbreak before the start of Phase II treatment, the fixed appliances can be delayed and the retentive phase extended by placing an upper anterior inclined plane to retain the corrected incisor relationship.⁶⁹

Fixed bite correctors are associated with high rates of breakage and more emergency visits compared with removable functional appliances.⁷⁰ Facial asymmetry, midline deviation, bite deepening, and occlusal cant changes are some of the detrimental effects of unmonitored therapy.

Aligners

Clear plastic aligners may offer some advantages in the COVID-19 era. A series of aligners is commonly provided to the patient for a set period (usually six to 12 weeks) before the patient returns for evaluation and additional aligners. Some orthodontists deliver all the aligners up front, saving storage space in the practice and reducing the number of in-office visits, and they may follow treatment progress online or with a remote monitoring system.

In the infrequent instance of loss or breakage of an aligner, the patient is usually advised to wear the previous aligner⁷¹ or, if unavailable, the next one in the series. If no aligner is available, a replacement “stage retainer” might be ordered from the manufacturer without a new digital scan. Fractured attachments can be replaced using one of the protocols described earlier to reduce aerosol generation during bonding.⁶¹

Virtual Tools

Given the unprecedented current situation, in which patient access to practices has been interrupted, virtual tools for dentistry⁷² and orthodontics have gained increasing popularity. Patients can use an array of available applications to take intraoral “selfies” with smartphones. These photos are automatically sorted, angulated, cropped, and organized by date. The orthodontist can access patient details at any time from any device through a common portal. Virtual prescreening or triage, as well as more immediate solutions to assess and monitor treatment and communicate with our patients, have been made possible by such digital tools.

A New Start

There is a good possibility that a future assault of COVID-19 would be even more difficult than the one we just went through. Hence, there is a need to develop clinical measures and guidelines for use in orthodontic practices during pandemics. As with any information in this continually evolving situation, it is most important that you do your own due diligence and carefully evaluate everything for yourself. We hope the measures and guidelines offered in this two-part series will stimulate thought and provide a rationale for: