The essential promise of implant dentistry is the ability to imperceptibly replace missing teeth. To achieve this, careful planning, execution, and maintenance is required by the dentist and patient to maintain a long-term esthetic and functional result. Unfortunately, as a result of biological, prosthetic, and iatrogenic factors, unesthetic results can occur. This article explores the potential causes for the unesthetic dental implant and the possible solutions that may improve the clinical situation. Whereas relatively simple errors may be corrected through prosthetic means, greater complications may require surgical intervention to achieve the desired result.
Esthetic complications are often the result of inadequate or absent planning that leads to implant malposition, which may or may not be overcome by prosthetic means.
Esthetic complications associated with relative discoloration of the crown and peri-implant tissues may be managed by use of alternative materials or enhancement of tissue thickness by surgical intervention.
The unfortunate decision to remove an implant to solve major esthetic complications requires extreme caution and estimation of the resulting tissue deficiency that must be compensated for before replacement of a dental implant in the proper position.
Esthetic complications regarding implant therapy depend on the observations and the observer. This subjective reality requires careful consideration of implant complications within clinical practice. Patient preferences, visual display (low lip line), and superimposed disease (peri-implantitis) must be considered differentially among various scenarios.
Esthetic complications related to implant therapy can broadly be characterized under 3 categories of origin ( Table 1 ): biological, prosthetic, and iatrogenic.
|Resorptive||Mucosal recession||Fracture||Implant, abutment, crown, prosthesis||Implant misplacement|
|Inflammatory||Mucosal hypertrophy, implant loss||Attrition||Crown, prosthesis||Cement retention|
|Positional change||Relative tooth intrusion||Color||Abutment, crown, prosthesis||Inappropriate prosthetic contours|
Identifying the biological and tissue architectural defect associated with esthetically failed implants requires consideration of the objective criteria for dental esthetics.
The treatment of unesthetic implants may require removal of the implant. Implant explantation can be an aggressive procedure, and complications in healing and complementary regenerative procedures may be needed ( Table 2 ). Therefore, each decision to remove an implant should be carefully measured. Different causes of implant esthetic deficits must be considered separately.
|Facial implant position||Loss of connective tissue attachment at adjacent teeth|
|Depth of implant placement||Implant proximity to adjacent tooth|
|Existing implant diameter||Existing implant diameter|
|Mucosal thickness||Mucosal thickness|
|Presence of keratinized tissue||Presence of keratinized tissue|
|Peri-implant mucosal inflammation||Peri-implant mucosal inflammation|
|Obvious infection||Obvious infection|
The inappropriate depth of implant placement creates esthetic challenges. The unesthetic result of shallow implant placement leads to inappropriately short restorations, the use of unhygienic flanges, or inappropriately contoured restorations. Shallow implant placement could be addressed by (1) using a short abutment with violation of the biological width, (2) use of a ridge lap design to mask the error, and/or (3) removal of the implant and replacement at the appropriate depth. In Fig. 1 , shallow (and buccal) implant placement precluded the planned and desired use of a fixed prosthesis. A more complex overdenture solution using custom conical abutments and locator attachments provided an esthetic solution. The motivated patient may choose to follow the route of implant replacement.
Depth of implant placement begins at the planning phase of treatment. In more complex scenarios, whereby tooth dimensions may change with ( Fig. 2 A), for example, crown lengthening, the location of the zenith must be defined before implant placement ( Fig. 2 B). When implants are positioned 3 to 4 mm apically from this position ( Fig. 2 C), implant esthetic harmony can be achieved with the surrounding teeth ( Fig. 2 D).
The unesthetic implant resulting from excessive depth of placement is challenged by the long-term continued facial tissue resorption to a point of biological stability (approximately 3 mm beyond the facial bone crest). The long crown associated with excessive depth of implant placement may benefit from a combination of prosthetic and surgical retreatment ( Fig. 3 ). Minor discrepancies in crown length may be successfully addressed by altering the facial contour of the abutment and crown. Providing sufficient thickness of facial tissue and an appropriately contoured (narrow) abutment may enable abutment coverage and development of suitable implant-crown cementoenamel junction location relative to adjacent teeth. However, deep implant placement aggravated by other factors such as adjacent implants, the loss of soft tissue, or additional buccal placement create problems that challenge prosthetic or surgical resolution ( Fig. 4 ).
Severe loss of vertical tissues can occur around implants ( Fig. 5 ). In the scenario illustrated in Fig. 5 , implant failure and associated bone loss was addressed by implant removal and immediate implant placement at an extremely deep location relative to adjacent teeth. Subsequently, loss of attachment at the adjacent teeth doomed the ultimate restoration despite the successful implant healing. This patient accepted treatment as the final result.
The unesthetic implant resulting from facial displacement of angulation often requires implant removal to secure success ( Fig. 6 ). The actual facial displacement should be distinguished from dehiscence that results from the deficiency of alveolar bone and loss of the buccal plate of bone ( Fig. 7 ). Box 1 demonstrates the differences between facial displacement of an implant and dehiscence of the buccal plate of bone. When there is loss of the buccal plate of bone, the regeneration of bone and mucosa may be attempted without removal of the dental implant. However, it is the authors’ opinion that this procedure be conducted following removal of the implant crown and abutment to permit spontaneous gingival regeneration to occur. This increases the volume of soft tissue and reduces the advancing of the flap and disruption of the mucogingival junction to accommodate grafting material volumes in the subsequent required procedures. When the implant must be removed, the resulting defect is typically a 3-walled defect. A flapless approach is not readily accommodated here. Furthermore, the impact of implant removal on the adjacent tooth connective tissue attachments must be predicted and minimized. Selecting the appropriate method of implant removal can influence the future outcome of therapy, and the least traumatic method should be selected. Four methods for implant removal are commonly reported and used ( Table 3 ). Each method has the potential to create additional tissue damage, particularly the trephine drill. The main advantage of reverse high-torque instrumentation is that the implant may be removed without significant architectural change to the surrounding bone. Other methods such as heating the implant (using electrocautery instrumentation) are not endorsed with enthusiasm.
Facial implant position or excessive implant angulation
Extreme depth of implant placement or shallow implant placement
Excessive implant diameter
Incorrect abutment dimension or contour
|Trephine drill||Widely applicable
|Requires full-thickness flap
Potential to destroy adjacent bone/teeth
Additional bone removed circumferentially
Contraindicated when interimplant-tooth distance is small
|Requires full-thickness flap|
|Requires full-thickness flap
More bone reduction than elevator method
No/small flap required
Useful when interimplant-tooth distance is small
|Limited use if coronal aspect of implant is fractured