A 4-year old hispanic female, healthy with no remarkable medical history attended a private pediatric dentistry clinic in Mexico City, Mexico, for an oral examination. The child was diagnosed with early childhood caries (ECC), preventive care and treatment plans were performed. The latter included four resin-modified glass ionomer restorations on: primary maxillary right second molar, primary maxillary right first molar and primary maxillary right cuspid and a full-coverage restoration on the primary maxillary left first molar.

The female child’s mother asked an esthetic restoration on the primary maxillary left first molar and was provided the options of: a) prefabricated zirconia crowns or b) an in-office custom-made resin crown restoration. It was explained to him that option b) was a recently technique uses new materials with the advantage of a custom-made, less expensive crown that would fit the tooth preparation with great accuracy and could be placed in the same appointment, as opposed to option a) where a standard pre-made zirconia crown required more trimming of the tooth to fit the crown. Given the novelty of this technique, and the uncertainty regarding the compressive and wear resistance of the material, they were offered two replacement crowns to be used in case of failure. She accepted, signed the informed consent, and appointments were scheduled.

The primary maxillary left first molar was trimmed in a way similar to a SSC preparation, but with a more occlusal reduction (2 mm) and a feather-edged one-millimeter subgingival preparation in the proximal, buccal, and lingual surfaces. The reduction of the occlusal surface was done with a coarse football-shaped diamond bur (368.021 SS White, Lakewood NJ, USA) followed by a circumferential reduction with a flame-shaped diamond bur (862-012C SS White, Lakewood NJ, USA) with a subgingival margin carefully extended to a feather-edge 1 mm subgingival on all surfaces, and an adequate proximal reduction to attain the correct fitting of the crown and to allow for contact with the adjacent tooth; finally, line and point angles were slightly rounded.

Once the tooth reduction was completed, a first gingival retraction cord (ROEKO Stay-put N^o 0, COLTENE/Whaledent AG, Altstätten, CH) was placed subgingivally all around the tooth, followed by a second retraction cord (ROEKO Stay-put N^o 1) placed in the same way. The second retraction cord was removed, and the tooth was rinsed with water spray. Leaving the first retraction cord in place (figure 1), we proceeded to scan the tooth with a intraoral scanner (CS 3600, Carestream Dental LLC, Atlanta, GA,USA); designed the crown with a chairside computer-aided design software (exocad GmbH, Darmstadt, Ger); and printed it with two more replicas in a 3D printer (Kulzer cara Print 4.0, KULZER, Mitsui Chemicals Group, Hanau, Ger) with a printable biocompatible resin material (dima Print denture resin, KULZER).

Once the crowns were printed (figure 2), were placed into an ultrasonic cleaner (BiosSonic UC125, COLTENE) in a container with isopropyl alcohol, for three minutes, followed by another three minutes washing in a container with water. The last step was the trimming and polishing of the crowns, preceded by a post-cured procedure in a composite curing oven (HiLite power 3D, Kulzer) for five minutes. One of the three crowns was chosen and cemented with a dual cure self-adhesive cement (RelyX™ U200, 3M™ ESPE, St. Paul, MN, USA). The entire procedure took 70 minutes, from the anesthetic infiltration to the crown cementation.

The patient returned to the office one week later with the fractured custom-made crown and bruxism was identified as the cause. One of the previously made replacement crowns was recemented, using a composite resin (Filtek™ Z350 XT, 3M™ ESPE) instead of the self-adhesive cement (figure 3), and the mother was given two other pre-printed replacement crowns.

Follow-up visit six months later showed a good clinical appearance of the crown with no fractures, good fit, no plaque retention and good gingival health (figure 4).