3D-printed reduction guide with hinge and window. Design for conservative veneer preparations.

AIM: Novel CAD/CAM dental techniques allow clinicians to digitally design and three-dimensionally print tooth reduction guides that enable more controlled and precise tooth preparations in the esthetic zone. The present case report introduces a new 3D-printed tooth reduction guide featuring a hinge and facial window, designed to facilitate minimally invasive veneer preparations. CLINICAL CONSIDERATIONS: A 36-year-old female patient presented at the clinic with the chief concern of improving her smile. Initial evaluation revealed existing ceramic veneer restorations extending from the maxillary right to left canine. The restorations exhibited staining and crack lines, and mild gingival recession was noted around the restored teeth. The patient was offered replacement of her current restorations with layered lithium disilicate veneers. She was also offered and accepted the use of a 3D-printed reduction guide with windows to facilitate conservative tooth preparation. MATERIALS AND METHODS: A diagnostic wax-up was completed, followed by an intraoral mock-up, approved by the patient for the proposed veneer restorations. A tooth reduction guide was digitally designed and 3D printed. A clear template of the proposed restorations was incorporated on the palatal (lingual) surface of the guide, allowing direct comparison of the tooth preparations with the planned restoration outlines. After conservative tooth preparation, a final impression was taken. The restorations were then handcrafted and bonded under complete rubber dam isolation. CONCLUSIONS: The treatment met the patient's esthetic expectations. The novel 3D-printed tooth reduction guide divided the facial surface of the anterior teeth into three horizontal thirds and included a clear template on the lingual surface, allowing the evaluation of the outline of the proposed final restorations. The guide could be secured over one third while enabling tooth preparation in the remaining sections. Overall, the guide design allowed for precise evaluation of the facial surface by thirds, while the lingual template provided an overview of the preparation relative to the final restoration contours.