Salvaging an implant with damaged internal threads · 2015. 10. 14. · A technique for salvaging...
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TIPS FROM OUR READERS Salvaging an implant with damaged internal threads Burak Yilmaz, DDS, PhD a and Faye Mascarenhas, BDS b Implant prosthetic dentistry is not problem-free, and clinicians face complications including screw loosening, screw fracture, abutment fracture, damaged abutment threads, and damaged implant threads. 1-6 Where the internal threads of an implant are damaged, they may become nonrestorable. Some techniques have been re- ported for salvaging the implant, 2,6 including fabrication of a conventional dowel and core. 2,3 However, this can cause extensive damage to the implant and may result in the need to remove it. Removal of the implant requires additional surgical procedures, increases cost, and delays restoration of the edentulous space. Implant internal threads can be retapped, and an abutment can be secured in the implant with the help of new threads formed with a tapping tool. Retapping threads allows the use of original implant prosthetic parts during the fabrication of a new restoration. This may improve the long-term success of the new restoration and the implant because a favorable implanteabutment connection can be achieved with the use of original parts. In addition, this technique is safer than the conventional post-core fabrication procedure. However, caution should be used during tapping to form proper threads and not break the tapping tool. The fit of screw threads to the retapped threads may also be inferior to a regular, manufactured screw thread-implant internal thread fit. Therefore, the restoration and the implant should be monitored for integrity at follow-up appointments. This report describes a procedure for salvaging an implant with damaged internal threads caused by a previously secured prefabricated, threaded root canal post in the implant screw hole (Fig. 1A, B). The loose crown and root canal post were removed. New threads were formed with a tapping tool, and a new crown was fabricated from original parts. PROCEDURE 1. Remove the loose crown with pliers (GC Pliers; GC America) and the prefabricated post with a post removal tool (CYTCO-K; Dentsply Intl) (Fig. 1C-E). Use a tissue punch (Salvin Dental Specialties) to expose the implant platform (Tapered Screw Vent; Zimmer Dental), which was completely covered with gingiva. Control the bleeding with a hemostatic agent (Viscostat; Ultradent Products Inc). 2. Attempt to screw a healing abutment (Zimmer Dental) to the implant to see whether it engages the internal threads of the implant. Make a periapical radiograph to evaluate whether the abutment is completely seated (Fig. 1F). Figure 1. A, Periapical radiograph of loose restoration with prefabricated post. a Associate Professor, Division of Restorative Sciences and Prosthodontics, College of Dentistry, The Ohio State University, Columbus, Ohio. b Resident, Division of Restorative Sciences and Prosthodontics, College of Dentistry, The Ohio State University, Columbus, Ohio. THE JOURNAL OF PROSTHETIC DENTISTRY 301
Transcript of Salvaging an implant with damaged internal threads · 2015. 10. 14. · A technique for salvaging...
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TIPS FROM OUR READERS
aAssociate PrbResident, D
THE JOURNA
Salvaging an implant with damaged internal threads
Burak Yilmaz, DDS, PhDa and Faye Mascarenhas, BDSb
Figure 1. A, Periapical radiograph of loose restoration with prefabricatedpost.
Implant prosthetic dentistry is not problem-free, andclinicians face complications including screw loosening,screw fracture, abutment fracture, damaged abutmentthreads, and damaged implant threads.1-6 Where theinternal threads of an implant are damaged, they maybecome nonrestorable. Some techniques have been re-ported for salvaging the implant,2,6 including fabricationof a conventional dowel and core.2,3 However, this cancause extensive damage to the implant and may result inthe need to remove it. Removal of the implant requiresadditional surgical procedures, increases cost, and delaysrestoration of the edentulous space.
Implant internal threads can be retapped, and anabutment can be secured in the implant with the help ofnew threads formed with a tapping tool. Retappingthreads allows the use of original implant prosthetic partsduring the fabrication of a new restoration. This mayimprove the long-term success of the new restorationand the implant because a favorable implanteabutmentconnection can be achieved with the use of original parts.In addition, this technique is safer than the conventionalpost-core fabrication procedure. However, cautionshould be used during tapping to form proper threadsand not break the tapping tool. The fit of screw threads tothe retapped threads may also be inferior to a regular,manufactured screw thread-implant internal thread fit.Therefore, the restoration and the implant should bemonitored for integrity at follow-up appointments.
This report describes a procedure for salvaging animplant with damaged internal threads caused by apreviously secured prefabricated, threaded root canalpost in the implant screw hole (Fig. 1A, B). The loosecrown and root canal post were removed. New threadswere formed with a tapping tool, and a new crown wasfabricated from original parts.
ofessor, Division of Restorative Sciences and Prosthodontics, College of Division of Restorative Sciences and Prosthodontics, College of Dentistry, Th
L OF PROSTHETIC DENTISTRY
PROCEDURE
1. Remove the loose crown with pliers (GC Pliers; GCAmerica) and the prefabricated post with a postremoval tool (CYTCO-K; Dentsply Intl) (Fig. 1C-E).Use a tissue punch (Salvin Dental Specialties) toexpose the implant platform (Tapered Screw Vent;Zimmer Dental), which was completely coveredwith gingiva. Control the bleeding with a hemostaticagent (Viscostat; Ultradent Products Inc).
2. Attempt to screw a healing abutment (ZimmerDental) to the implant to see whether it engages theinternal threads of the implant. Make a periapicalradiograph to evaluate whether the abutment iscompletely seated (Fig. 1F).
entistry, The Ohio State University, Columbus, Ohio.e Ohio State University, Columbus, Ohio.
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Figure 1. (continued) B, Intraoral view of loose restoration. C, Frontal view of prefabricated post after removal of loose restoration. D, Implant siteafter removal of prefabricated post. E, Loose restoration, prefabricated post, and post removal tool. F, Periapical radiograph of ill-fitting healingabutment. G, Thread tapping tool in handle.
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THE JOURNAL OF PROSTHETIC DENTISTRY Yilmaz and Mascarenhas
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Figure 1. (continued) H, Thread tapping tool in implant. I, Radiograph of tapping tool in implant. J, Radiograph of seated impression post. K, Radiographof abutment.
Figure 2. Intraoral view of definitive crown.
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3. If the abutment does not engage the implant’s in-ternal threads and the misfit between the abutmentand implant can be radiographically confirmed, usea tapping tool (model 172UWF thread tap; ZimmerDental) to form new threads in the internal surfaceof the implant (Fig. 1G).3 Remove the head of thetool if it is too large to use between the adjacentteeth (Fig. 1H).
4. Use the tapping tool in a clockwise direction, andeach time resistance is felt, remove the tool in acounter clockwise direction. Exercise caution duringretapping and rinse the internal surface of theimplant with water after each attempt. Repeat theprocedure until a proper depth is achieved for animpression post to completely seat (Fig. 1I).
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5. Evaluate the impression post (Zimmer Dental) onthe implant, and make a radiograph to determinewhether the impression post is completely seatedon the implant platform (Fig. 1J).
6. Once the impression post is completely and securelyseated, make a definitive impression with polyvinylsiloxane impression material (Aquasil Ultra; Dents-ply Caulk) for the fabrication of a definitive crownon the implant with the new internal threads(Fig. 1K, Fig. 2).
REFERENCES
1. Goodacre C, Kan JY, Rungcharassaeng K. Clinical complications of osseoin-tegrated implants. J Prosthet Dent 1999;81:537-52.
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2. Pipko DJ, Kukunas S, Ismail YH. Retrofitting a cast dowel-core on salvageddental implants. J Prosthodont 2004;13:52-4.
3. Pow EH, Wat PY. A technique for salvaging an implant-supported crown witha fractured abutment screw. J Prosthet Dent 2006;95:169-70.
4. Imam A, Yilmaz B, Ozcelik TB, McGlumphy EA. Salvaging an angled implantabutment with damaged internal threads: A clinical report. J Prosthet Dent2013;109:287-90.
5. Yilmaz B, McGlumphy E. A technique to salvage a single implant-supportedfixed dental prosthesis having a nonretrievable implant screw fragment. J OralImplantol 2013;39:81-3.
6. Yilmaz B, McGlumphy E. A technique to retrieve fractured implant screws.J Prosthet Dent 2011;105:137-8.
Corresponding author:Dr Burak YilmazDivision of Restorative Sciences and ProsthodonticsThe Ohio State University College of Dentistry305 W 12th AveColumbus, Ohio 43210Email: [email protected]
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Salvaging an implant with damaged internal threadsProcedureReferences
