Article

Feature Article
Oct 28, 2015 // 6 min read
Esthetic Implant Complications: An Introduction
Stuart J. Froum
DOI: 10.3290/iti.fi.45689
Esthetic implant complications

High implant survival rates for implant-supported restorations (>90%) have been reported in the literature (Adell et al. 1990, Buser et al. 1997, Linquist et al. 1996, Wennstrom et al. 2005). Traditionally, the words “implant survival” were equated with “implant success”. Success was defined by Albrektsson as “an implant with no pain, no mobility, no radiolucent peri-implant areas, and minimum bone loss of less than 0.2 mm annually following the first year of loading (Albrektsson et al. 1986). Roos-Janasaker added to this definition by further defining a successful implant as one that loses no more than 1.0 mm of bone of bone during the first year post-placement (Roos-Janasaker et al. 1997). 

However, a surviving implant may equally well not be considered a success. Implant success has been defined as any implant-supported restoration in which 1) the treatment plan was performed without complications, 2) implants placed remain stable and functioning without complications, 3) the peri-implant soft and hard tissue remains healthy and stable, 4) the patient and clinician are pleased with the result (Froum et al. 2012). Today the parameters for implant success also include the esthetic appearance of the final implant restoration (Froum et al. 2010).

Implant complications have been classified as surgical, biological, related to placement or loading, mechanical and esthetic (Froum et al. 2012). When a complication occurs with implant esthetics, however, it may be related to any or all of the parameters listed. Esthetics, in fact, is so essential that in assessing the degree of difficulty one classification using a S(Straightforward), A(Advanced), C(Complex) system regards all implants placed in the esthetic zone as Complex (Dawson et al. 2009).

In fact, in the soon-to-be-published 2nd edition of Dental Implant Complications: Etiology, Prevention and Treatment approximately half of the 30 chapters are devoted directly to or include information on implant esthetics and complications related to this aspect of implant-supported restorations (Froum 2015).

The prevalence of complications has been reported in several reviews. According to the results of a systematic review on complication rates of implant-supported fixed partial dentures, implant success is about 61% (Pjetursson et al. 2004). According to a 10-year follow-up implant study, complications have been reported to occur in over 50% of implants (Lang 2004). In the study by Pjeturrsson et al that looked at implant-supported fixed partial dentures (FPD), the most common technical complication was fracture of veneers (13.2% after 5 years) followed by loss of the screw access hole restoration (8.2%). In another review of all types of implant-retained prostheses (Goodacre et al. 2003), the most common technical complications were loosening of the overdenture retentive mechanism (33%) followed by resin veneer fracture with FPDs (22%). However, when considering esthetic implant complications, there are a number of areas ranging from risk assessment, treatment planning, implant site preparation, implant placement, provisional temporization, final prosthetic fabrication and placement through maintenance, all of which can be a source of complications while at the same time remaining essential steps for an esthetic restoration. In an excellent chapter in the ITI Treatment Guide Volume 1, the authors discuss diagnostic factors for esthetic risk assessment (Martin et al. 2007). In a detailed analysis (in Dental Implant Complications, 2nd Edition) of the same topic in a chapter on complications associated with single implant esthetics, the authors again identified risk factors for an esthetic implant outcome (Andrade et al. 2015).

Dr. Martin discusses risk assessment in this issue of Forum Implantologicum, and one of the key elements in implant esthetic success is the patient’s treatment expectations. The clinician must evaluate the hard and soft tissue at the implant site, use the information gleaned from a computerized axial tomographic (CAT) or cone beam (CB) scan and determine if there is sufficient quantity and quality of tissue to place and restore the implant to satisfy the patient’s expectations. If there is not, soft and hard tissue augmentation procedures should be employed prior to or in conjunction with implant placement (Figs 1a - c & 2a - b). 

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Fig. 1a: A radiograph of an implant that was placed in the maxillary right 1st molar without proper augmentation of the surgical site
Fig. 1b: The computerized axial scan shows the implant with inadequate buccal and lingual bone
Fig. 1c: The resulting restoration is esthetically poor with an unhappy patient
Fig. 2a: Two implants to replace two missing central incisors were inserted without site development
Fig. 2b: To restore these implants, pink material (composite) was utilized. This represents an attempt at a prosthetic solution to poorly planned implant insertion. The patient was not happy with the outcome
Fig. 1a Fig. 1b Fig. 1c Fig. 2a Fig. 2b

An ideal wax-up shown and approved by the patient should be the starting point. Oftentimes restoration of adjacent teeth is required to obtain the desired esthetics in assessing patient expectations. This must be discussed with the patient, the surgeon, the restorative dentist and the laboratory technician when planning the treatment. The wax-up can also furnish a radiographic and surgical guide to plan and complete implant placement (Figs 3a - d).

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Fig. 3a: Edentulous maxillary right central incisor area (#8)
Fig. 3b: A surgical guide made on an ideal wax-up with the maxillary central incisor included
Fig. 3c: The surgical guide used for proper positioning of the osteotomy for tooth #8
Fig. 3d: An occlusal view of the guide placed in the osteotomy guided by the surgical stent
Fig. 3a Fig. 3b Fig. 3c Fig. 3d

Proper three-dimensional implant placement using the guide is essential to position the implant to receive a well-fitting esthetic restoration (Figs 4a - c).

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Fig. 4a: Pre-surgical site of a missing maxillary left canine
Fig. 4b: Use of a surgical guide from an ideal wax-up allowed proper positioning of the implant seen in the periapical radiograph
Fig. 4c: Implant-supported restoration with excellent esthetics
Fig. 4a Fig. 4b Fig. 4c

Implant malposition is one of the most common complications and in most cases will interfere with an esthetic restoration. The importance of proper thickness of the buccal plate of bone as well as the distance between implant and natural tooth and implant to implant have been discussed and documented by several authors. In this issue of Forum Implantologicum, Drs Buser and Belser will discuss the above relative to the problem of complications with adjacent implants (Figs 5a - b & 6a - b).

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Fig. 5a: A radiograph of multiple adjacent implants placed without adequate mesial-distal spacing
Fig. 5b: Clinically, this resulted in a lack of interproximal bone and papillae leading to biofilm and calculus accumulation, and peri-implantitis
Fig. 6a: A radiograph showing two adjacent implants in the maxillary left-central and lateral areas
Fig. 6b: Restoration of these implants leads to an asymmetrical and unesthetic result with long interproximal contact lines to compensate for the missing papillae
Fig. 5a Fig. 5b Fig. 6a Fig. 6b

Another key element affecting the survival and success of implant restorations is the timing of implant placement and loading protocols. These can vary from immediate (on the day of tooth/teeth) extraction, early, early delayed, or delayed. This topic is covered in two excellent chapters in Dental Implant Complications, 2nd Edition (Ganeles et al. 2015, Wagenberg et al. 2015, and will also be discussed in this issue of Forum Implantologicum by Drs. Belser and Buser. The choice of placement and loading depends on the post-surgical extraction site, implant stability, and soft and hard tissue bone levels. Oftentimes, as with pre-surgical site preparation, augmentation procedures are necessary to obtain the desired esthetic result (Figs 7a - d).

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Fig. 7a: Prior to removal of the hopeless maxillary left-central incisor, probing depth, bone loss, and an x-ray revealed the extraction site required hard tissue augmentation in conjunction with the extraction
Fig. 7b: Following healing, the edentulous site and adjacent teeth presented with sufficient hard and soft tissue for proper implant placement
Fig. 7c: The implant and final restoration. Note the bone levels on the adjacent teeth were adequate to support the interproximal papillae
Fig. 7d: Proper 3-dimensional implant placement into the prepared site resulted in an esthetic outcome
Fig. 7a Fig. 7b Fig. 7c Fig. 7d
Conclusions

When evaluating outcomes of implant therapy in the anterior maxilla of partially dentate patients, esthetic appearance as perceived by both the patients and clinicians involved, is nowadays widely considered an integral part of the list of pertinent success criteria. In fact, esthetic implant complications are not uncommon, highly unpleasant for patients and care providers, as well as particularly difficult to correct once they have occurred. Most frequently, inadequate implant recipient site preparation, malpositioned implants and non-observance of optimal distances between implant shoulders and adjacent roots or between adjacent implants are at the origin of esthetic complications. For these reasons, it is of paramount importance to foster a prevention-oriented treatment approach. This includes comprehensive esthetic risk assessment first of all, followed by meticulous therapeutic execution, often including demanding implant site development prior to correct 3D implant positioning. In this context, the use of surgical templates derived from a diagnostic wax-up may play a decisive role in both pre-surgical site preparation and subsequent adequate 3D implant positioning. And by this token make the difference between success or esthetic complication.