Articles - Forum Implantologicum

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Feature Article

Oct 28, 2015 // 8 min read

Esthetic Implant Failures: Potential Causes and Techniques for Implant Removal

Dental implants esthetic complications esthetic failures implant malposition adjacent implants oversized implants implant removal

Abstract

In recent years, a marked increase in esthetic implant complications and failures has been observed. This article focuses primarily on esthetic failures, i.e. severely compromised treatment outcomes, mostly making implant removal unavoidable. The first part enumerates the most frequent causes of such failures, namely implant malposition, adjacent implants and oversized implants. Regrettably, it is concluded that the origin of the majority of the problems described is directly related to insufficient preoperative esthetic risk assessment on the one hand and poor execution of the surgical procedure on the other. The latter comprises errors in 3D implant positioning, namely implants placed too far facially, too close to adjacent natural roots or to additional implants, not infrequently combined with non-observance of the prosthetic implant axis and oversized implant dimensions. Consequently, prevention of esthetic implant failures should underline that this highly demanding segment of implant dentistry requires specially qualified and experienced clinicians, as clearly defined by the ITI’s SAC classification. The second part of the article presents state-of-the-art implant removal technology, including instruments and procedure, illustrated by a step-by-step case presentation.

Introduction

Implant therapy in the esthetic zone is a challenge for the clinicians involved. Therefore, implant therapy in the anterior maxilla is considered to be either advanced or complex according to the SAC Classification by the ITI (Dawson & Chen 2009). The most challenging are indications in partially edentulous patients such as single tooth gaps or extended edentulous spaces. Several clinical studies, most of them examining esthetic single tooth replacement with implant-supported crowns, showed very satisfactory esthetic outcomes (Belser et al. 2009; Buser et al. 2013).

In the past 15 years, the referral of patients with esthetic complications and failures has become more frequent in our department. With the widespread utilization of dental implants and a certain trend that general practitioners are encouraged to place dental implants, it can be predicted that esthetic complications and failures will continue to rise in daily practice. The present publication will discuss the potential causes of esthetic implant failures, and state-of-the-art surgical techniques to remove osseointegrated implants. In addition, a typical case report will be presented.

Fig. 1a: Clinical view of a tissue level implant restoration at site 11. Insufficient inter-proximal distance between the implant shoulder and the two adjacent natural roots led to a severe mucosal recession at the facial aspect of the embrasure 11/12

Fig. 1b: The corresponding x-ray confirms insufficient inter-proximal distances between implant shoulder and adjacent roots

Fig. 2a: Clinical view of a tissue level implant restoration at site 21. Note both the severe mid-facial mucosal recession and a visible metal margin

Fig. 2b: After implant crown removal, a pronounced facial malposition of the implant shoulder becomes apparent

Fig. 2c: The corresponding conventional 2D x-ray confirms stable inter-proximal peri-implant bony conditions

Fig. 2d: However, the 3D CBCT image documents the distinct facial malposition and absence of a facial bone wall

Fig. 3a: Clinical view of an implant restoration at site 11. Note both the severe mid-facial mucosal recession and a visible metal margin

Fig. 3b: The corresponding conventional 2D x-ray confirms stable inter-proximal peri-implant bony conditions

Figs 3c: However, the 3D CBCT image documents a labial implant axis, a distinct facial malposition of the implant shoulder and the absence of a facial bone wall in the coronal portion of the implant. Furthermore, one can note an oversized implant platform

Fig. 4a: Clinical view of a tissue level implant restoration at site 24. Note both the severe mid-facial mucosal recession and exposure of the coronal part of the implant

Fig.4b: After removal of the implant crown one can observe the facial implant axis associated with facial and coronal malposition of the implant shoulder

Fig. 5a: Clinical view of an implant restoration at site 12. Note both the severe mid-facial mucosal recession and exposure of the coronal part of the implant that was inadequately covered with plastic restorative material

Fig. 5b: After implant crown removal, an extreme labial implant axis becomes apparent

Figs 5c - d: The 3D CBCT images document a labial implant axis, a distinct facial malposition of the implant shoulder and the absence of a facial bone wall in the coronal portion of the implant. Furthermore, one can note an extremely oversized implant

Fig. 6a: Clinical view of two adjacent tissue level implant restorations at sites 11 and 12. One can note a short inter-implant papilla that has been partly compensated by a long interdental contact line. In order to create the optical illusion of balanced relative tooth dimensions by highlighting the transition line angles, a slightly more saturated shade has been used interdentally in the cervical part

Fig. 6b: The corresponding x-ray confirms stable peri-implant bony conditions, but a typical flattening of the inter-implant bone crest

Fig. 7a: Clinical view of two adjacent tissue level implant restorations at sites 22 and 23, displaying severe mid-facial mucosal recession and exposure of the coronal part of both implants. The inter-implant distance is clearly insufficient

Fig. 7b: The occlusal view also documents a facial malposition of both implants

Fig. 7c: The corresponding x-ray confirms the insufficient inter-proximal distance

Fig. 8a: Clinical view of three adjacent tissue level implants at sites 11, 21 and 22, displaying severe mid-facial mucosal recession and exposure of the shoulder of the implants. The inter-implant distances are clearly insufficient

Fig. 8b: The patient’s non-forced smile with the provisional removable partial denture in place visualizes the significant negative impact of the malpositioned implants on esthetic appearance

Figs 8c: The two x-rays reveal the coronally malpositioned three implants. Furthermore, the implant shoulder 22 has been located too close to both the adjacent implant 21 and tooth 23

Fig. 9a: Clinical view of three facially malpositioned adjacent tissue level implants at sites 12, 11 and 21, displaying severe mid-facial mucosal recession and exposure of the coronal part of the implants. The patient is wearing a cemented 3-unit fixed dental prosthesis (FDP) with integrated pink acrylic

Fig. 9b: The conventional 2D x-ray reveals advanced peri-implant bone loss, particularly marked around implants 12 and 11. Inter-implant distances, however, can be considered sufficient

Fig. 9c: The corresponding 3D CBCT images document that all three implants are in a facial malposition. Note the almost complete absence of a facial bone wall. In addition, one can observe that angulated abutments have been used, indicating implant axes that are inappropriate from a restorative point of view

Fig. 10a: The implant removal kit consists of five different sized conical screw devices featuring a counter-clockwise screw thread that makes it possible to engage the coronal prosthetic interface of most major implant systems

Fig. 10b: Overview picture of the BTI® implant removal kit

Fig. 10c: The BTI® implant removal kit includes a ratchet to apply a counter-clockwise torque to the implant via the previously described conical screw device

Fig. 11a: A sixty-year old female patient’s non-forced smile visualizes the significant negative impact on esthetic appearance, namely the exposure of metal, created by several malpositioned implants in the right maxilla

Fig. 11b: The facial close-up view reveals five adjacent implants supporting a screw-retained provisional FDP. Note that the screw-access channel of the center implant is located mid-facially

Fig. 11c: The occlusal view documents that the two implants supporting restorations 15 and 16 are facially malpositioned

Fig. 11d: The 2D x-ray view of the right maxilla underlines various types of implant malpositions in regard to inter-implant distance, implant depth as well as implant axis

Fig. 11e: The corresponding 3D CBCT images document that all five implants can be considered to feature at least one type of malposition. Most common findings comprise absence of a facial bone wall, inadequate restorative axis, as well as insufficient inter-implant distance and errors in insertion depth. In addition, implant 17 has perforated the maxillary sinus

Fig. 11f: In order to offer the patient the comfort of an implant-supported FDP throughout the entire treatment period, it was decided in a first phase to remove only implants 14, 15 and 16. As a consequence, implants 13 and 17 were kept at this stage. During the following implant removal procedure, the screw-access was blocked-out with Teflon® plugs

Fig. 11g: Clinical view with the counter-clockwise screw of the BTI® system engaged in the implant and the corresponding ratchet attached

Fig.11h: The three implants were removed without elevating a surgical flap

Fig. 11i: The resulting bony defects were filled with Bio-Oss® collagen as in socket grafting

Fig. 11j: Full thickness mucosal grafts harvested from the palate with an appropriate punch device were used to completely close the implant removal sites. A limited number of interrupted sutures were applied to secure the grafts

Fig. 11k: The 1-month follow-up view documents uneventful and complete soft tissue healing

Fig. 11l: Occlusal view after insertion of the new 5-unit screw-retained metal-ceramic FDP

Fig. 11m: Lateral view of the final implant-supported FDP

Fig. 11n: The x-ray of the final implant supported FDP confirms stable peri-implant bony conditions and adequate marginal fidelity of the suprastructure

Fig, 11o: The patient’s non-forced smile at the end of treatment