J Korean Acad Prosthodont.  2016 Oct;54(4):423-430. 10.4047/jkap.2016.54.4.423.

Clinical cases of implant-supported fixed dental prosthesis using modified lingual screw system (T-screw system)

• Hong TY
• Kim MY
• Yoon JH

• KMID: 2388222
• DOI: http://doi.org/10.4047/jkap.2016.54.4.423

Abstract

The implant prosthesis can be divided into the screw retained prosthesis and cement retained prosthesis. Each type has advantages as well as disadvantages which is unfavorable to maintain the implants. To overcome these drawbacks, T-screw system was developed. T-screw system which utilizes a lingual direction of the screw to retain the implant prosthesis, has advantages of retrievability of the prosthesis, passive fit, and possibility to form esthetic and functional occlusal surface. The prior prosthesis which utilized horizontal screws had difficulty in fabrication especially in the case of multiple units, and also limited use with all-ceramic prosthesis. In this case, fabricating the implant prosthesis by using the T-screw system showed superior results in easy maintenance, esthetics, and also functions. In addition, we are to report the method of using the T-screw system in implant prosthesis, such as multiple units of implant prosthesis and all ceramic prosthesis.

Keyword

Dental implant; Implant-supported dental prosthesis; Dental restoration failure; Dental restoration repair; Peri-implantitis

MeSH Terms

Ceramics
Dental Implants
Dental Prosthesis*
Dental Prosthesis, Implant-Supported
Dental Restoration Failure
Dental Restoration Repair
Esthetics
Methods
Peri-Implantitis
Prostheses and Implants
Dental Implants

Figure

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  Fig. 1. Schematic diagram of the T-screw system. (A) Occlusal view, (B) Cross-sectional view.

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  Fig. 2. Panoramic radiograph. (A) Pre-operative panoramic radiograph, (B) Post-operative panoramic radiograph.

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  Fig. 3. Final impression taking. (A) Index cap and impression cap, (B) Index caps were used to duplicate internal thread of implants, (C) Connection of impression cap for taking impression, (D) Impression of Mandible, (E) Master cast of Mandible.

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  Fig. 4. Registration of centric relation. (A, B) Connection of Lucia jig for neuromuscular reprogramming, (C) Registration of centric relation with Lucia jig and silicon bite material.

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  Fig. 5. Try-in of framework. (A, B) Try-in of framework fabricated after connection of T-screw housing. (C) Centric relation registration with Lucia jig.

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  Fig. 6. Clinical pictures and panoramic radiograph after the placement of definitive prosthesis. (A) Frontal view, (B) Right buccal view, (C) Left buccal view, (D) Mandibular occlusal view, (E) T-screw located on lingual side, (F) Panoramic radiograph.

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  Fig. 7. Panoramic radiograph. (A) Pre-operative panoramic radiograph, (B) Post-operative panoramic radiograph.

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  Fig. 8. Final impression taking and fabrication of master cast. (A) SP indicator for duplicate internal thread of implants, (B) Marking the direction of ALIPS, (C) Connection of impression cap for taking impression, (D) Impression of mandibular arch, (E) Master cast connected with ALIPS, (F, G) Verifying the same direction of ALIPS.

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  Fig. 9. Fabrication and try-in of framework. (A) Fabrication of framework using zirconia, (B) Holes on lingual side for t-screw housing, (C, D) Try-in of framework.

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  Fig. 10. Clinical pictures and panoramic radiograph after the placement of definitive prosthesis. (A) Frontal view, (B) Maxillary occlusal view, (C) T-screw located on lingual side.

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