Consecutive treatment failures of an immediate maxillary canine implant and the subsequent replacement and reconstruction of the site

The approach to treating an edentulous or partially edentulous jaw presents both clinician and patient with a clinical challenge addressed by several treatment options (Misch 2015).

Restorative implant treatment is among the more advanced options, and yet it is highly predictable and potentially very rewarding for the patient. Fundamental principles, though, are to be adhered to (Moraschini, et al., 2015).

Chief among these is thorough, concise, evidence-based treatment planning (Thajli 2016). The clinician is cautioned not to overlook the crucial importance thereof. All too often neglected are the most basic of examinations and thorough history taking. The reader may challenge himself/herself and ask, “When last did I carry out a standard, full mouth periodontal examination to identify any periodontal disease that requires treatment before embarking on implant therapy?” (Cho-Yan, et al., 2012)

Thorough implant treatment planning almost always necessitates the use of special investigations and additional diagnostic aids. While costly, the value of a cone-beam computed tomography (CBCT) scan to visualize the edentulous ridge or site in its three-dimensional aspects cannot be stressed enough (Du Toit, et al., 2015). The treating clinician is to be cognizant of the recommended tissue parameters needed to support the dental implant and its restoration. The clinician is required to diagnose the need to augment these (Levine, et al., 2014; Puisys and Linkevicius 2015; Urban, et al., 2009).
Figure 1: The preoperative presentation
Figure 2: A draining sinus was noted buccal to the implant crown at UR3

The previously mentioned by no means addresses the entirety of the possible implant treatment planning aspects. However, the main shortcomings are highlighted, drawing attention to the case presented here and what led to the treatment failure.

Case report

A 21-year-old male presented with the main complaint of a persistent infection around an implant that had been placed about 1 year prior. The patient was a nonsmoker, healthy, with a clear medical history and currently not taking any chronic medication. According to the patient’s history, the infection had persisted, and the practitioner who placed the implant advised the patient that the situation was not a problem. The patient’s history entailed a retained deciduous canine with a congenitally missing tooth at UR3. The deciduous tooth was removed, and an immediate implant was inserted at the site. The implant developed an infection and was removed.

A second implant was placed at the time of the first’s removal. This implant also became infected and was subsequently removed. The patient then saw a different practitioner who placed a third implant and restored it after a period of healing.

Subsequent to the chronic draining sinus buccal to the implant, the patient was advised by his general dentist to seek a third opinion. Clinical examination of the patient noted a screw-retained, implant-supported crown at the UR3. Circumferential probing of the implant exceeded 15 mm, with bleeding upon probing, and exudate draining from a sinus midfacial at the implant site (Figures 1 and 2).

CBCT examination noted a custom abutment that extended about 8 mm-10 mm in length, screw-retained to an external connection implant. The implant-abutment interface was positioned at approximately as deep as the root apices of the adjacent teeth with about half the implant body penetrating into the nasal cavity (Figure 3).
Figure 3: Preoperative CBCT showed a dental implant with about half the body inserted into the nasal cavity, a root remnant buccal, and an angled abutment as long as the implant fixed to a crown restoration

Figure 4: Full-thickness flap exposure of the site revealed an extensive buccofacial bony defect and soft tissue encapsulation of the implant abutment
Figure 5: Removal of the pathological soft tissue revealed the extent of the bony destruction
Figure 6: The abutment was torqued to fracture, revealing an external hex connection implant
Figure 7: The infective tissue at the implant and root remnant
Figure 8: After removal, the restoration and abutment to implant ratio could be appreciated
Figure 9: After initial healing of the site. Note the mesial of tooth 14 that was cut away. And the horizontal defect, as well as the extensive scarring is evident
Figure 10: Tooth UR4 was restored. Occlusal view accentu-ates the buccal defect
Figure 11: Re-entry at the site illustrated the extent of the horizontal defect
Figure 12: The radiographic-surgical guide in position and zenith of the pontic
Figure 13: Placement via the guide confirmed a restoratively planned implant

There was also evidence of a root fragment adjacent to the implant. The extended custom abutment supported a cement-retained crown in the occlusal position. The UR4 had been reduced mesially to accommodate the implant crown.

A detailed examination predicated the diagnosis of a severely malpositioned implant with a chronic peri-implantitis and unacceptable restoration. The treatment planning proposed removal of the implant and restoration, allowing for a period of healing and resolution of infection, and a reassessment of the site’s treatment needs.

The site was anesthetized, and a full-thickness flap was raised over the implant at UR3, exposing soft-tissue encapsulation of the abutment extending to the apices of the adjacent teeth (Figure 4). The pathologic soft tissue was removed to send for histological examination, and the extent of the bony destruction at the area was exposed (Figure 5).

Bone appeared eroded at the surfaces proximal to the implant. The buccal bone had a large defect, yet the palatal bone remained coronal. The prosthesis and restoration were torqued and fractured from the implant, and thereafter, the implant torqued out (Figures 6-8). The root fragment was also located and removed, the area meticulously debrided, and copiously rinsed with saline.

Platelet-rich fibrin (PRF) membranes were placed within the defect, and the site sutured closed with 6/0 nylon. After 8 weeks of healing, the edentulous site was reapproached and treatment planned from the start.

This included among many others a thorough clinical exam, periodontal examination, a holistic documentation of all pathologies and treatment needs, concise photographic documentation, study casts, restorative mock-up, and special investigative adjuncts, including CBCT.

The diagnostic list for the patient included a Class I malocclusion, recession defects, a mild fluorosis, and a missing UR3. Diagnosing the healed, edentulous site at UR3 noted a significant ridge defect, both horizontal and vertical, with a deficit of both hard and soft tissues. The soft tissue already showed significant scarring, recession distal to UR2, and severe recession mesial to UR4 with complete loss of the papillae (Figures 9 and 10).

There was insufficient attached, keratinized tissue at the UR4 with a Class IV recession defect. The treatment planning entailed a bone augmentation of the hard tissue defect, augmentation of the soft tissue deficit, and implant placement to restore with a screw-retained crown.

The UR4 was first restored to re-establish a normal emergence profile and anatomy (Figure 10). CBCT and virtual implant planning indicated that implant placement in the restoratively correct three-dimensional positioning with simultaneous augmentation with an autogenous corticocancellous bone block was a viable option.

After local anesthesia, a full-thickness flap was again raised at the site, and the implant osteotomy was prepared via a restoratively planned surgical guide (Figures 11 and 12). A morse taper conical internal connection implant, (3.5 mm x 10 mm NobelActive®, Nobel Biocare®) was inserted at the correct restoratively planned level, 2 mm below the palatal crest (Figures 13 and 14).
Figure 14: The implant fully inserted with an extensive buccal dehiscence that required augmentation
Figure 15: The ramus block sectioned into two thinner grafts
Figure 16: Harvesting of the ramus block
Figure 17: Bone shavings harvested by scraping and refining the block grafts
Figure 18: The blocks fixed to the bony ridge buccal to the implant
Figure 19: Buccal view of the bone blocks fixed in place
Figure 20: The harvested autogenous bone shavings were packed beneath and around the blocks.

A corticocancellous bone block was then harvested from the left mandibular ramus and split into two block veneer grafts as per Khoury’s protocol (Figures 15 and 16). The blocks were thinned with a bone scraper (SafeScraper, Geistlich) further harvesting autogenous bone shavings (Figure 17). The blocks were then secured to the ridge buccal to the implant with fixation screws and the bone shavings packed within the defect between the implant and blocks (Figures 18- 20). PRF membranes were layered over the bone augmentation and the tension-free flap repositioned and sutured with 6/0 nylon (Figures 21 and 22).

Figure 21: PRF membranes were layered atop the completed bone augmentation
Figure 22: Site closure with 6/0 nylon sutures
Figure 23: Immediate postoperative periapical radiograph. This short, wide healing abutment is not idea
Figure 24: 12 weeks of healing
Figure 25: CBCT scan showed the healed bone augmentation buccal to the implant 2.2 mm thick
Figure 26: ISQ readings indicated high stability, positively confirming osseointegration
Figure 27: The connective tissue graft (CTG) harvested from the palate positioned over the recipient site
Figure 28: The implant exposed with CTG inserted and sutured inside a split-thickness tunnel flap
Figure 29: 10-day follow-up with the provisional restoration in place. The soft tissue augmentation healing without complication
Figure 30: Four-week follow-up, soft tissues healed, provi-sional in place, yet the absence of a distal papilla is obvious
Figure 31: A further 8 weeks allowed for soft tissue maturation and infill of the distal inter-proximal space
Figure 32: The final screw-retained crown in place. Adequate bulk of tissue buccal to the implant restoration
Figure 33: Two-year follow-up, tissues stable with adequate esthetic and functional results

The site was then restored with a provisional partial denture free of pressure to the underlying
augmentation site.

After 12 weeks of healing, the implant was exposed, and its implant stability quotient (ISQ) checked — 78D 75M 75B (Figures 23-26).

The buccal soft tissue was undermined by a tunneling approach, creating a split-thickness envelope. A connective tissue graft (CTG) was harvested from the palate and transferred into the pouch, sutured in position, thereby augmenting the soft tissue buccal and coronal to the site (Figures 26-28).

The implant was then restored with a provisional restoration to begin developing the soft tissue profile.

At 4 weeks of healing, a black triangle was evident where the distal papilla was absent. A further 8 weeks of healing allowed time for soft tissue in-fill of the area (Figures 28-31).

At final restoration of the implant, a bulk of ridge tissue buccal to the implant could be noted, with near complete restitution of both mesial and distal papillae (Figure 32).

Functional treatment goals were realized, and adequate esthetic rehabilitation of the previously failed treatment was achieved. The patient was satisfied, with the tissues and outcomes remaining stable at the 2-year recall (Figure 32).

Discussion

It is likely that with the ever-increasing availability of implant treatment, a greater number of implant procedures will produce increasing implant failure data (Derks, et al., 2016; Tarnow 2016).

Implant treatment has become commonplace in daily practice, yet the practitioner should never discount the importance of a correct approach and healthcare fundamentals (Kuchler and von Arx 2014; Tahmaseb, et al., 2014; Bornstein, et al., 2014). The foundation thereof is a comprehensive patient history, thorough clinical examination, the use of special adjunct investigations where necessary, a review of the patient’s risk factors — all to derive accurate diagnoses (Levine, et al., 2014; Buser, et al., 2017).

It is evident from the failed case presented here that these principles were not adhered to. The site and its retained root were not diagnosed properly, and thus, the patient went through multiple and unnecessary procedures that ultimately required extensive reconstruction to rehabilitate the site.

The ridge deficits were not diagnosed correctly, and the need for bone and soft tissue augmentations was not identified. The value of a CBCT scan in planning implant treatment cannot be overemphasized
(Bornstein, et al., 2014; Bornstein, et al., 2014; Nunes, et al., 2013).

Literature does not necessitate CBCT as an absolute for every implant treatment case planned, but it is difficult to identify a planned implant, verifying adequate bone circumferential to the implant, and to locate anatomical structures of risk to orientate a correct restoratively planned placement positioning (Buser, et al., 2017; Harris, et al., 2012).

Sound knowledge of the principles of implant dentistry is essential when delivering such treatment to a patient, and the clinician is required to have a thorough understanding of anatomy, biology, and prosthodontics as well as implant hardware.

Evident in the original failed treatment, knowledge of the minimum bone required to accommodate the implant inserted at the correct height and position to ensure long-term tissue stability was lacking (Levine, et al., 2014). Recognizing the need for a soft tissue augmentation that in turn supports healthy bone at the implant — which can be developed and sculpted to frame the implant restoration, potentially creating pseudopapillae, as with the revised rehabilitation presented here — was also lacking (Linkevicius and Apse 2008).

The attempt at placing a non-internal conical connection implant, and attempting to restore at occlusal level via a highly unconventional customized abutment contributed to the failure. Compromising established, evidence-based, reliable procedures and opting for an alternative compromise introduce a debate for clinical innovation versus jeopardizing treatment.

But in this case, the third implant placement and restorative approach were both indisputably unacceptable. It is accepted clinical practice to place an implant beyond the sinus or nasal floor cortex contained within an intact membrane and most often a bone augmentation when a vertical ridge deficiency presents in the maxilla (Mazor, et al., 2012; Sanz, et al., 2015). But entirely perforating into the nose and placing a large portion of the implant body unsupported by augmented bone is not clinically acceptable and does not contribute to the integration of the implant.

Of greatest concern in the case presented here was the disregard for the principles of beneficence and non-maleficence that underpin modern healthcare. The persistent infection was not addressed, and the underlying cause, likely the infected root fragment, was not diagnosed. The failure of the previous two implant treatment attempts should have been investigated. Moreover, the UR4 should not have been cut away to accommodate the implant restoration. Managing increased crown height space to implant ratio is acceptable and common at resorbed, post-extraction sites. But extending a customized abutment trans-gingivally to bring the crown into occlusion — as with this case — is not acceptable.

The cantilever forces exerted in the failed treatment are not conducive to health (Anitua, et al., 2014). Moreover, the soft tissues when healed at the neck of an implant crown seek to establish a biological zone, commonly of long junctional epithelium with underlying connective tissue along the abutment (Linkevicius and Apse 2008).

A tissue seal and attachment along the entirety of the failed abutment here was unlikely. As such, the long junctional epithelium may allow for bacterial plaque ingress and colonization along the length of the abutment that cannot be cleaned by the patient, resulting in the infective, granulation tissue seen at the implant’s removal (Canullo 2011).

Conclusion

A lack of sound knowledge in implant dentistry and an attempt at a compromise resulted in a drastic failure that required several additional procedures to rehabilitate. The failure presented here underpins the importance of basic and fundamental principles when approaching any treatment. Proper examinations, diagnoses, and treatment planning that substantiate ethical treatment options are key to a successful treatment outcome.