Restoration of a Microdont Using the Resin Composite Injection Technique With a Fully Digital Workflow: A Flexible 3D-printed Index With a Stabilization Holder

K Watanabe; A Tichy; K Kamoi; M Hiasa; K Yonekura; E Tanaka; M Nakajima; K Hosaka

doi:10.2341/23-007

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Article Contents

SUMMARY
INTRODUCTION
CLINICAL REPORT
DISCUSSION
CONCLUSIONS
Acknowledgments
REFERENCES

Editorial Type:

Article Category: Case Report

Online Publication Date: 15 Sept 2023

Restoration of a Microdont Using the Resin Composite Injection Technique With a Fully Digital Workflow: A Flexible 3D-printed Index With a Stabilization Holder

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Page Range: 483 – 489

DOI: 10.2341/23-007

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SUMMARY

Direct composite restorations are accepted as a treatment option for microdontia, which is a relatively prevalent condition that poses esthetic concerns. While free-hand composite placement is technique-sensitive and time-consuming, the resin composite injection technique is more straightforward and predictable. A fully digital workflow has been recently introduced, but the 3D-printed resin index is rigid and challenged by undercuts, as opposed to the silicone index. This case report presents a flexible 3D-printed resin index, which can accurately transfer the digitally simulated functional and esthetic form to the final restoration. In addition, a rigid stabilization holder was designed to stabilize the flexible index.

Figure 1

Post-orthodontic situation (A) and pre-operative situation after tooth bleaching (B-D).

Figure 2

Digital dentition before (A) and after digital wax up (B-D).

Figure 3

(A) Import the digital wax-up model. (B) Create 1.5 mm offset. (C) Cut off unnecessary portions except targeted tooth and adjacent teeth. (D) Determine the position of the stabilization holder. (E) Provide lingual and palatal extensions for the stabilization holder to fit. (F) Determine the injection hole position. (G) Cut out the injection hole from the index. (H) The index design completed.

Figure 4

Digital designs of the index (A, B) and the stabilization holder (C, D). The bucco-palatal extensions are indicated by the white arrows (A, B). The occlusal window of the stabilization holder is indicated by the black arrows (C, D).

Figure 5

3D-printed flexible index from various angles: buccal view (A), lingual view (B), and inside views (C, D). The incisal opening is indicated by the white arrow (B, C), while the openings corresponding to the contact points on the mesial and distal wall are indicated by black arrows (D).

Figure 6

3D-printed rigid stabilization holder (A) used to secure the 3D-printed flexible index on a 3D-printed model (B-D). The clip buccolingually to hold the index firmly in place (indicated by black arrows), while manual pressure applied to the occlusal surface improves the marginal adaptation of the index to the cervical region of the dentition (indicated by white arrows)(C, D).

Figure 7

Composite injection technique using the 3D-printed flexible index with the stabilization holder. (A) Operative field isolation. (B) Phosphoric acid enamel etching with Teflon tape used to protect adjacent teeth and (C) application of adhesive. (D) Injection of a universal-shade injectable resin composite through the incisal opening of the flexible 3D-printed index. (E) Light curing of the composite through the stabilization holder, with additional light curing after clip removal (F). (G,H) Remaining 3D-printed resin and excess composite are visible after removal of the 3D-printed flexible index. (I) They are removed and ultrasonic scaler with lower power. (J) Finishing of the cervical margin using an ultrafine diamond bur and a cup shaped medium coarse silicon point (K). Polishing using a cup-shaped super fine silicon point (L) and a polishing strip (M), was completed (N). The postoperative views of the restoration (O,P).