New Resins for Digital Indirect Bonding of Brackets | Case Study

BY Aivy

Digital indirect bonding is here to stay! Orthodontists are revisiting indirect bonding granted that more software platforms are offering this service and more clinics have a desktop 3D printer in their office. Integration of digital technology in particular 3D printing (additive manufacturing) in the daily practice of orthodontics, as well as digital dentistry in dental practices, introduces changes in patient experience in orthodontic practices. The ability to print the IDB trays in-office allows a quicker start of treatment by eliminating the tray shipping time. Digital orthodontics includes protocols and approaches to use digital technology in the practice of orthodontics. All the digital workflows can be done at the office or outsourced to a lab.

This is a short report comparing KeyOrtho IBT resin and IDB 2.0 SprintRay resin for 3D printing workflow of an indirect bonding tray. These trays were fabricated using 3D printing materials chairside.

The new indirect bonding resin (IDB resin 2.0) from SprintRay was redesigned to improve the following issues with the original IDB resin.

Flexibility of the tray
Tear of the tray
Smell of the resin
Print time
Clarity of the tray
Optimization of printing with support structures
Printing detail structure of a tray (sharp edges)

This is a report on indirect bonding of KLOWEN brackets with IDB digital trays generated using the OrthoSelect software – a digital orthodontic bracket placement program. IDB trays were printed on the SprintRay Pro 55. We used SprintRay IDB 2.0 trays on the right side and KeyOrtho IBT trays on the left side of the mouth. This is an observational report with an intention to provide insights on two fairly new products on the market within the limitation of a case report study.

Digital indirect bonding tray — IDB 2.0 tray resin tray

IDB trays were printed on low-density high-strength supports. The print time ranged 25-30 mins at 100 micron thickness layer.

The upper tray was digitally cut between the upper centrals. The lower tray was digitally cut between the lower right central incisor and lateral incisor because of the lower anterior mild crowding to reassure enough walls on the tray to support the lower anterior brackets. The KeyOrtho IBT trays have a blueish tint and the IDB 2.0 trays are clear.

3d printing indirect bonding trays

Trays were printed at 100 microns using a SprintRay 55 printer. Print time was 25-30 mins with both resins – including the 4mm supports. We were interested in the impact of support by the design software on these trays. Alternatively, one can 3D print these bracket transfer trays flat on the build platform. SprintRay is a DLP printer. Formlab 3D printers offer a similar option with their library of resins.

One can alternatively print dental models and fabricate conventional indirect bonding trays from an intraoral scan stl file. This approach requires a silicon material to separate the adhesive on the bracket mesh to the 3D model.

Post printing wash and dry

We followed our conventional post-processing to

IDB 2.0 resin was easier to remove with 99% IPA. One cycle of wash (9 mins in a wash and dry unit) was adequate to clean IDB 2.0 trays.

Trays printed with KeyOrtho IBT were washed for two cycles of 9 mins in the wash and dry unit. We followed the manufacture’s instructions to eliminate all the glossy spots of liquid resins*.*

Note that the KeyOrtho IBT resin is more viscous at room temp compared to IDB 2.0 resin.

Post printing cure

IDB 2.0 trays were cured for 45 mins at 50 degrees based on the manufacturer protocol. KeyOrtho IBT trays were cured 5 mins per side (total of 10 mins) at 50 degrees.

Bonding

Brackets were placed in the trays at the clinic. Both trays printed with IDB 2.0 and KeyOrtho IBT had a similar great grip of the brackets. The KeyOrtho IBT trays are stiffer than IDB 2.0 trays. They were easily removed with no bonding failure after they were heated for 2-3 mins using a tooth dryer.

The teeth were etched and primed and all trays were delivered at the same time. Right side of the mouth was bonded using the IDB 2.0 trays and the left side of the mouth were with KeyOrtho IBT trays.

No bond failure was observed after removal of the trays. All teeth including second molars were bonded at this appointment.

What are the differences between resin used in digital indirect bonding and resin for other technologies?

IDB resins requirements a medical device FDA approval. Trays 3D printed by these resins needs to be biocompatible since it will be in contact with intraoral tissue.

Takeaway

IDB 2.0 or KeyOrtho IBT are both great resins to use for the in-office IDB tray fabrication. The wash and dry is slightly easier for IDB 2.0 and the cure time is shorter for the KeyOrtho IBT. IDB 2.0 printed trays are more translucent than IDB 1.0 and KeyOrtho IBT; this could positively impact the efficiency of curing adhesive materials. Removal of both trays did not result in bond failure for this patient. Similar observational evaluation of these resins is required to validate the predictability of success with indirect bonding with trays using these two resins.

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