6.1 Implant Placement in the Esthetic Zone and Coverage of Multiple Gingival Recessions

S. Aroca

Presenting complaint

A 47-year-old woman was referred by her general dental practitioner for the treatment of generalized gingival recessions and the extraction of tooth 21 due to external root resorption. The patient had high esthetic expectations. Her main concern was the appearance of the anterior teeth and their “elongation.” The patient had no symptoms related to the resorption process on root 21 but had been advised of the condition by her practitioner.

Clinical examination revealed multiple gingival recessions on the facial aspect of the anterior maxillary teeth from 14 to 24, with an otherwise stable periodontal status and good plaque control (GI = 0; PI < 10%) (Table 1; Fig 1).

Table 1 Periodontal indices at presentation.

Cone-beam computed tomography (CBCT) scans confirmed the external resorption of tooth 21. The loss of the facial cortical plate is evident (Figs 2a-b).

Taking into consideration the patient’s high esthetic expectations, the following treatment approach was proposed:

Multiple root coverage extending from tooth 14 to tooth 24 by using the modified tunnel technique (Aroca and coworkers 2013). The patient received detailed explanations on the surgical root coverage using by one of the following two options:

• Connective-tissue graft harvested from the palate

• Soft-tissue augmentation using a collagen matrix as grafting material

After a detailed explanation of the procedures, risks, and benefits, the patient preferred the second option and consented to the surgical procedure.

Treatment procedures

All teeth from 14 to 24 were splinted with composite at the incisal angles to support suspended sutures. During this first phase of the treatment, tooth 21 was retained to facilitate better support for the coronally advanced tunnel (Azzi and Etienne 1998; Aroca and coworkers 2010; Aroca and coworkers 2013) underneath which a trimmed 30 × 40-mm collagen matrix was placed (Mucoderm; Botiss Biomaterials, Zossen, Germany) (Figs 3a-b).

There was a discrepancy of the available mesiodistal gap width at site 21 due to tooth rotation. Six months after the first surgical phase and before the extraction of tooth 21, orthodontic treatment was performed to increase the mesiodistal distance of site 21. The extraction of the upper left incisor was followed by a socket preservation technique according to the GBR principle. The Bio-Gide membrane was briefly placed between the inner surface of the soft-tissue pouch and the buccal bone, ensuring that the size of the membrane exceeded the contour of the bony lesion. The socket was filled with particles of deproteinized bovine bone mineral (Bio-Oss and Bio-Gide; Geistlich, Wolhusen, Switzerland) (Figs 5a-d). The socket opening was closed with a connective-tissue graft harvested from the palate using the single-incision technique (Hürzeler and Weng 1999). A single incision was made between the distal aspect of the canine and the mesial aspect of the second molar. An adequate size of the CTG was obtained to seal the socket. The donor site was sutured with modified-horizontal mattress sutures (5-0 polyglactin 910, Vicryl; Ethicon, Johnson & Johnson, New Brunswick, DE, USA).

Six months after the tooth extraction and socket preservation, an implant was placed (RC BLT, diameter 4.1 mm, length 8 mm: Institut Straumann AG, Basel, Switzerland) using a tunnel approach (Aroca and coworkers 2010; Aroca and coworkers 2013) without releasing incisions, and the marginal mucosa was augmented using a connective-tissue graft from the palate (Fig 7).

A provisional crown was fitted immediately upon completion of the surgical procedures. Figures 8a-b show the clinical and radiological situation at three weeks with the provisional crown in place.

All sites of gingival recession remained successfully covered, with stable peri-implant hard and soft tissues 2.5 years after the prosthetic restoration (Figs 11 and 12).

Discussion

The modified tunnel technique is a technique described first by Azzi and Etienne (1998) and Aroca and coworkers (2010; 2013). The “tunnel” flap is created using a full-thickness dissection extended beyond the mucogingival junction and under each papilla, so that the flap can be moved in a coronal direction without tension. Muscle fibers and any remaining collagen bundles on the inner aspect of the mucosal flap are cut using Gracey curettes with extreme care to avoid perforation of the flap and to obtain a passive coronal positioning of the flap and the papilla.

The collagen matrix was then inserted under the modified tunnel at the sites of recession and retracted laterally by sutures towards each end of the tunnel. After positioning the collagen matrix laterally, the site was rinsed with saline solution to remove any clots. Then the flap was coronally repositioned, slightly above the cementoenamel junction, with suspended sutures around the contact points (Azzi and Etienne 1998; Aroca and coworkers 2010; Aroca and coworkers 2013) (Fig 3b), which allowed complete coverage of the collagen matrix.

This approach has demonstrated to be highly effective in root coverage procedures for Miller class 1, 2, and 3 multiple recession defects (90% and 83%, respectively) (Aroca and coworkers 2010; Aroca and coworkers 2013).

The proposed technique will not only cover the gingival recession, but also augment the tissue across the anterior area, including the planned implant site.

The gingival phenotype (thin vs. thick) is of paramount importance in implant dentistry, especially in the esthetic zones of the mouth, a thick phenotype being associated with a reduced risk for soft-tissue recession following crown delivery (Evans and Chen 2008).

Ridge preservation was performed to enhance the possibility of maintaining the shape and volume of the alveolar area, reducing the effect of bone remodeling following tooth extraction (Mardas and coworkers 2015; MacBeth and coworkers 2017; Avila-Ortiz and coworkers 2019).

6.2 Periodontal Plastic Surgery and Prosthetic Procedures to Treat Peri-Implant Soft-Tissue Dehiscences

P. Casentini

A 30-year-old woman was referred by her general dentist for evaluation of an esthetic complication related to previous implant treatment for congenitally missing maxillary lateral incisors.

The patient’s chief complaint was the inadequate esthetic appearance of her smile. She reported that 10 years ago, she had been treated with dental implants for the replacement of the two congenitally missing incisors. Following the initial treatment, the patient was satisfied with the overall treatment outcome, but the esthetic appearance progressively deteriorated over the following years.

Her previous dental history and current condition did not reveal any other significant dental or periodontal pathology in her remaining dentition. The patient was not taking any medication and reported being in good general health. She had realistic esthetic expectations for the outcome of treatment.

The extraoral examination revealed a high smile line, with full exposure of maxillary teeth and surrounding soft tissues up to the first-molar region (Fig 1).

The intraoral examination showed two asymmetric implant-supported cemented crowns on teeth 12 and 22, with exposed implant abutments and discoloration of the peri-implant soft tissues (Fig 2).

The soft-tissue phenotype was classified as thin and highly scalloped, with slight gingival recessions at the adjacent teeth. The peri-implant probing values ranged from 2 to 4 mm, with no bleeding on probing. The patient presented with good oral hygiene with a full-mouth plaque score (FMPS) of less than 15%, and the full-mouth probing chart did not reveal any pockets deeper than 3 to 4 mm.

The central incisors were misaligned. The occlusal view confirmed mild incisor crowding and an excessively buccal position of the lateral incisor crowns (Fig 3).

An intraoral photograph taken with a polarizing filter confirmed and highlighted the presence of the soft-tissue discoloration at the buccal aspect of the implant crowns (Fig 4).

Intraoral radiographs showed adequate osseointegration of the implants with limited coronal bone remodeling (Figs 5 and 6).

Esthetic analysis

The following issues did not represent an adequate esthetic appearance (Fig 7) when compared to average parameters (Magne and Belser 2002):

• Different shapes of the two lateral incisors; there was an obvious difference in crown length

• Diverging axes of the two lateral incisors rather than being slightly convergent to the midline

• Different soft-tissue levels: in particular, the soft-tissue level at site 12 was too far coronal compared to the adjacent teeth. Conversely, the tissue level at site 22 was too far apical

• The two central incisors had different incisal-edge levels

Treatment planning

Based on the clinical and radiological situation, retention of the existing implants was judged possible and seemed a more convenient option in terms of morbidity and cost. An alternative treatment option would have been the removal of the existing implants and placement of new implants after soft- and hard-tissue augmentation; this was considered too invasive. The following treatment plan was proposed:

• Preliminary orthodontic treatment to relieve crowding and improve the tooth alignment

• Removal of the old crowns and placement of new temporary crowns

• If possible, removal and reshaping of old implant abutments

• Periodontal plastic surgery to increase the thickness of the peri-implant soft tissues and to obtain an optimal position of the peri-implant soft-tissue margins in relation to the future crown, as well as to treat the gingival recessions on the adjacent teeth

• Final prosthetic reconstruction with new ceramic crowns on 12 and 22

The patient rejected the orthodontic treatment for financial and time reasons and wished to limit the periodontal plastic surgery, if possible, to the implant sites only. She agreed to the rest of the proposed treatment plan and gave her written informed consent.

Preliminary prosthetic procedures

Following the removal of the old crowns (Figs 8 and 9), the abutments were unscrewed and the chamfer finishing line was changed to a vertical edge (Fig 10). This procedure creates more space for the soft tissues and is considered an important step prior to soft-tissue grafting (Zucchelli and coworkers 2013b). Peri-implant probing after abutment removal confirmed the absence of deep pockets and bleeding on probing.

After reconnecting the abutments (Fig 11), two resin temporary crowns were relined with autopolymerizing resin and cemented to the abutments (Fig 12).

Periodontal plastic surgery

Since the surgical objectives differed between sites 12 and 22, different flap designs were selected for each.

At site 12, there was no need of coronal advancement of the soft-tissue margin; the main goal of surgery was to increase the thickness of the marginal soft tissues. Therefore, it was decided to use a tunneling technique, which is usually less invasive (compared to flap elevation) and results in a faster healing process. Conversely, at site 22, where the surgical objective was coronal advancement of the soft-tissue margin combined with soft-tissue thickening, a coronally advanced flap (CAF) with a connective-tissue graft was selected.

Surgery was performed under local anesthesia in two separate steps.

Site 12. The prosthetic abutment was removed to simplify surgical access. Then a tunnel was created with a microsurgical blade (Spoon Shape 2.0 mm; Omnia, Fidenza, Italy) (Figs 13a-c and 14).

Once the tunnel was created, a connective-tissue graft was harvested from the area of the maxillary tuberosity (Fig 14).

If the tuberosity is available as a donor site, using it has a number of benefits (Roccuzzo and coworkers 2014b), as a high-quality, dense connective-tissue graft without fatty tissue can be harvested here with a reduced risk of postoperative bleeding and without major postoperative pain.

The harvested tissue was subsequently reshaped and de-epithelized with a #15C surgical blade (Fig 15).

The graft was then pulled inside the tunnel using 6-0 resorbable polyglycolic-acid sutures (Vicryl Ethicon; Johnson & Johnson Medical, New Brunswick, NJ, USA) (Fig 16). Another suture stabilized the graft horizontally at the recipient site (Fig 17). Finally, after cementation of the temporary crown, the graft was stabilized vertically by a suspended suture bonded to the crown with flowable composite (Fig 18). Chlorhexidine mouth rinses were prescribed for three weeks together with a non-steroidal anti-inflammatory medication for pain relief. The patient was advised to avoid brushing the operation sites for three weeks.

The sutures were removed at two weeks. No complications were recorded, and the patient did not report significant symptoms. Surgery for site 22 was planned after a healing period of six weeks (Fig 19).

Site 22. After removal of the temporary crown, a trapezoidal partial-thickness flap was elevated to improve the revascularization of the graft. Mesial and distal releasing incisions were extended 2 mm apically to the mucogingival line. The partial-thickness flap was extended over the mucogingival line and the muscle fibers were sectioned to allow coronal advancement of the flap without tension (Figs 20 and 21).

The exposed implant surface (less than 1 mm) was polished with a diamond bur and rinsed with sterile saline and chlorhexidine gel. Subsequently, a connective-tissue graft harvested from the left maxillary tuberosity was de-epithelized and fixed to the buccal periosteum with resorbable 7-0 polyglycolic-acid sutures (PGA; Stoma, Emmingen-Liptingen, Germany) (Figs 22 and 23).

After fixing the connective-tissue graft, the flap was coronally advanced to completely cover the graft. Finally, the flap was secured in its final position with 6-0 resorbable sutures (Vicryl Ethicon; Johnson & Johnson Medical, New Brunswick, NJ, USA) (Fig 24). The temporary crown was shortened to avoid any apical pressure on the soft tissues and recemented on the abutment (Fig 25). The same postoperative instructions and medication were provided as after the first surgery.

Impressions for the final reconstruction

After six months of healing, the peri-implant tissues appeared fully healed and it was possible to confirm the presence of a thick and stable layer of soft tissue around the implants (Figs 26 and 27).

The screw access holes of the abutments were sealed with white composite, and closed-tray impressions for new ceramic crowns were taken using a polyether material (Impregum and Permadyne; 3M Espe, Seefeld, Germany). Prior to impression-taking, the soft tissues were gently retracted with cords placed in the peri-implant sulcus, using the temporary crown to aid insertion (Figs 28 and 29).

Delivery of the final reconstruction

A working model was poured and metal-ceramic crowns were manufactured. To optimize the esthetic result, the dental technician provided a ceramic finishing line (Figs 30 to 32).

After verifying the correct fit and esthetic integration and following approval by the patient, the ceramic crowns were cemented with a glass-ionomer cement (Rely-X Luting, 3M Espe), with the excess cement being carefully removed (Figs 33 to 36).

The final view of the restorations demonstrated a favorable esthetic integration of the crowns in the surrounding soft tissues, and in the smile of the patient. Post cementation radiographs confirmed stability of the peri-implant bone levels and absence of residual cement. The patient declared herself fully satisfied with the outcome of the treatment.

Three-year follow-up

At the three-year clinical and radiological follow-up, the peri-implant soft tissue and bone contours were seen to be stable, with the favorable esthetic outcome being maintained. The patient was recalled every six months for professional oral hygiene and a clinical check-up and has always demonstrated a high standard of oral hygiene. No increased periodontal probing depth and bleeding on probing were recorded at the implant sites at any of the follow-up visits. The control radiographs showed a stable peri-implant bone level. The patient confirmed that her esthetic expectations had been fully met (Figs 37 to 42).

Discussion

Periodontal plastic surgery to treat soft-tissue dehiscences around dental implants is a relatively recent topic in implant dentistry. Despite limited scientific evidence, mostly comprising case reports and case series, some prospective studies have been published (Burkhardt and coworkers 2008; Zucchelli and coworkers 2013b, 2018b; Roccuzzo and coworkers 2014b) and more recently a literature review (Mazzotti and coworkers 2018). A combined surgical and prosthetic approach (Zucchelli and coworkers 2013b) seems to provide the best results in terms of soft-tissue dehiscence coverage when compared to a pure surgical approach (Burkhardt and coworkers 2018; Roccuzzo and coworkers 2014b).

For this reason, the first treatment step in the present case was aimed at changing the shape of the original implant abutments to provide more space for soft-tissue spontaneous thickening and for the subsequent grafting procedure. Different surgical techniques were utilized for each side. At site 12, the position of the soft-tissue margin was considered adequate, and the treatment goal was mainly soft-tissue thickening to avoid abutment visibility through the soft tissues. A tunnel technique was selected as less invasive (Zuhr and coworkers 2018).

At site 22, the desired treatment outcome was not only soft-tissue thickening but also coronal advancement of the soft-tissue margins through a coronally advanced flap. On both sides, the preferred grafting material was autologous connective tissue, which has demonstrated the best results (Anderson and coworkers 2014 (Burkhardt and coworkers 2008; Zucchelli and coworkers 2013b; Roccuzzo and coworkers 2014b) and it appears to provide satisfactory long-term results (Zucchelli and coworkers 2018b).

Acknowledgments

Laboratory procedures

Alwin Schoenenberger, Vision-Dental – Chiasso, Switzerland and Busto Arsizio, Italy

6.3 GBR and Soft-Tissue Augmentation Following Explantation to Rehabilitate a Soft- and Hard-Tissue Defect

R. Cavalcanti, P. Venezia

Dental implants have become more widespread in recent years—unfortunately sometimes excessively so. A particular problem seems to be that implants are sometimes performed by surgeons who have not enjoyed the benefits of rigorous relevant training.

Dental implants are a valuable resource when resolving situations related to tooth agenesis or loss of teeth due to trauma or illness. They allow esthetics and function to be restored in partially or fully edentulous patients. However, with the increasing number of implants placed, emerging evidence indicates that implants can, over time, lead to a series of technical and, more seriously, biological complications (Derks and coworkers 2016). This presents new challenges in terms of the prevention and treatment of these complications to obtain predictable and stable results over time.

These complications, which must now be considered common, (Giannobile and Lang 2016), often involve not only hard tissues, but also peri-implant soft tissues and can compromise the longevity of implants, with the result that it is sometimes necessary to remove and replace compromised implants.

There have been various proposals for the treatment of peri-implant biological complications so as to preserve the compromised implants, for the treatment of bone defects (Schwartz and coworkers 2012; Roccuzzo and coworkers 2011) and for soft-tissue deficiencies (Burkhardt and coworkers 2008; Zucchelli and coworkers 2013b; Roccuzzo and coworkers 2014b). However, there are no universally accepted protocols for the different complications encountered in the clinical setting. There is even less evidence regarding the protocols to be followed when removing implants and replacing them with new ones.

The criteria that define an implant as non-salvageable and requiring explantation can include:

• Lack of response to conventional conservative and surgical treatment

• Interference with normal function

• Hazards to the health and stability of the tissues of adjacent teeth or implants

• Implant retention that would imperil the possibility of eventual replacement due to progressive bone destruction

Presenting complaint

A 35-year-old woman, healthy and in good physical condition, presented with esthetic concerns related to an implant-supported restoration replacing teeth 14 and 13 (Fig 1).

Diagnostic aspects and preoperative examination

The patient presented with clinical attachment loss on the proximal and lingual surfaces of the natural dentition. Some gingival recession was present on natural teeth, particularly in the posterior sextants (S1, S3, S4, and S6). Several conservative and prosthetic restorations, some of which would have to be replaced, were also present. At baseline, the full-mouth bleeding score (FMBS) was 54%, while the full-mouth plaque score (FMPS) was 62%, 72% of sites presented with a periodontal probing depth (PPD) of less than 4 mm; 23 % of sites, of 4 to 6 mm; and 5% of sites, of more than 6 mm.

Sextant S1 contained an implant-supported restoration at site 13–14, with a large buccal recession defect partially compensated for with pink ceramics applied on the prosthetic device. Teeth 17 and 18 were missing, having been extracted in the past due to caries.

The patient reported that both the implants and the prosthesis had been placed approximately four years previously. The radiographic examination showed significant bone loss around the two implants, particularly in the severely limited interimplant space (Fig 2). Peri-implant probing revealed bleeding on probing (BOP) and 9 mm of pocket depth between the two implants (Fig 3). Tooth 12 was buccally inclined, with gingival recession of about 4 mm, Miller class III (Miller 1985) and Cairo RT2 (Cairo and coworkers 2011). The patient’s tissue phenotype was markedly thin (Figs 1 and 4).

The diagnosis was peri-implantitis at implants 13 and 14, with extensive bone loss and extensive buccal mucosal recession as a consequence of incorrect three-dimensional positioning of the implants, which were judged to be untreatable, having been placed in close proximity and preventing appropriate oral hygiene.

Treatment objectives

The aim was to resolve the functional and esthetic problems in sextants S1 and S2. The following treatment options were considered:

Option 1

Removal of compromised implants; reconstruction of hard and soft tissues; placement of a new standard-diameter implant 14 to support a new prosthesis with a mesial cantilever restoration (Aglietta and coworkers 2009, 2012), and root coverage of 12 by means of periodontal plastic surgery. Using a cantilever extension to replace tooth 13 was suggested because the patient presented with an open bite between teeth 13 and 43 and the lateral guidance was part of the group function on the premolars and first molar.

Option 2

Removal of compromised implants; reconstruction, in a staged approach, of hard and soft tissues: placement of two narrow-diameter implants 14 and 13 with two new implant-supported crowns: root coverage of tooth 12 by means of periodontal plastic surgery.

A further option for the replacement of the missing teeth using a tooth-supported fixed partial denture was rejected due to the length and non-linear shape of the required bridge that would be needed and the additional need for endodontic treatment of the mesial abutment (tooth 12) due to its buccal position and angulation.

It was decided to proceed with Option 1 in order to place as few implants as possible to avoid potential problems arising from interimplant crowding and a lack of access for oral hygiene.

Treatment procedures

An initial phase of non-surgical periodontal therapy, with oral hygiene instructions and motivation using an effective but non-traumatic brushing technique, was followed by a first surgical phase that involved the removal of the compromised implants.

A full-thickness flap was raised to provide adequate access to the implants and surrounding tissues (Fig 5). The implants were removed, leaving a wide through-and-through buccopalatal bone defect with a large vertical component (Fig 6). The need for primary wound closure dictated the use of a free gingival graft to bridge the gap between the buccal and palatal soft tissues. The graft was partially de-epithelialized and placed as an inlay, leaving the epithelialized component exposed (Figs 7 to 12).

The sutures were removed after two weeks (Fig 13) and the patient was recalled every four weeks for the next four months.

Four months later, the patient underwent a second surgery to rebuild the bone tissue lost as a result of peri-implant disease (Figs 14 and 15). Hard-tissue reconstruction was performed by placing small blocks of cortical bone, taken from the mandibular ramus, to create the walls of a box to be filled with autologous bone chips (Figs 16 to 19). A slow-resorbing xenograft layer (DBBM, Bio-Oss; Geistlich Pharma, Wolhusen, Switzerland) was placed on the surface and covered with a resorbable collagen membrane (Bio-Gide; Geistlich Pharma) (Figs 20 and 21). Primary tension-free closure was achieved by the coronal elevation/advancement of the full-thickness flap with periosteal releasing incisions at the bottom/base of the flap while aiming to cover the root of tooth 12 (Fig 22).

The sutures were removed two weeks later (Figs 23 and 24) and the patient was followed for the next six months.

At the end of this period, a third operation was performed to insert the planned implants (Figs 25 to 31). As confirmed during the normal preoperative planning phase, it was decided to place only one implant at site 14, replacing tooth 13 with a cantilever extension (Aglietta and coworkers 2009, 2012). An implant (Tissue Level RN Roxolid SLActive, diameter 4.1 mm, length 10 mm; Institut Straumann AG, Basel, Switzerland) was placed simultaneously with a connective-tissue graft mesial to the implant in the pontic region.

After a healing period of about three months (Figs 32 and 33), the implant was loaded with a screw-retained provisional restoration with crown 13 attached as a cantilever.

However, edentulous ridge of the canine site had a residual concavity that was corrected by further surgery, placing a connective-tissue graft associated with vestibuloplasty (Figs 34 to 37).

Soft-tissue healing and conditioning was guided by means of the temporary restoration; it is ideally suited to this purpose, being relatively simple to modify at chairside by adding or reducing material to exert pressure until satisfactory soft-tissue scalloping has been achieved (Figs 38 to 40).

Once the desired result is obtained, it is important to replicate the soft-tissue profile in the master cast used for the fabrication of the final prosthesis.

Conventional impression techniques are not effective in reproducing the soft-tissue profile because the soft tissues tend to collapse immediately after the removal of the provisional restoration. This is because the soft tissues have been conditioned and individualized during the provisional phase; in many esthetic cases, the transmucosal depth will be deep and difficult to register with a conventional impression.

Since the provisional should perform as an exact replica of the final restoration, it was crucial to transfer the soft-tissue conditioning outcome using a simple, fast, and accurate technique (Hinds 1997) (Fig 41).

First, the provisional restoration was connected to an implant analog and embedded in silicone up to the maximum circumference of the provisional bridge.

As soon as the silicone had set, the provisional restoration was removed and an impression transfer connected to the implant analog. The gap between the impression transfer and the silicone walls of the block was filled with low-shrinkage acrylic resin (Pattern Resin; GC, Tokyo, Japan) (Fig 42).

The customized impression coping (Figs 43 and 44) will allow an accurate transfer of the emergence profile and the pontic area.

The remaining clinical stages are the same as in the standard impression technique (Fig 45). More recently, new techniques have been described for a fully digital approach for the registration of the peri-implant mucosa and pontic areas (Monaco and coworkers 2016; Venezia and coworkers 2017).

The definitive restoration was placed four months later (Figs 46 and 47). It had been planned as a screw-retained monolithic zirconia framework (produced with a milling machine) with feldspathic ceramic veneering limited to the buccal surface (Venezia and coworkers 2015).

At the end of treatment, FMPS was 13% and FMBS was 11%. There was no site with PPD greater than 6 mm, and 14% of sites exhibited a PPD of 4 to 6 mm. The patient was placed on a maintenance program with recall intervals every four months. The patient was greatly satisfied with the result, which was found to be stable at the two-, three- and five-year follow-up visits (Figs 48 to 51).

Discussion

Implants allow us to solve different problems related to edentulism and provide our patients with adequate function and esthetics. However, implants will not infrequently develop various complications of their own, especially in the presence of incorrectly managed risk factors or as the result of incorrect three-dimensional positioning, whether of single implants and of adjacent multiple implants. In particular, placing implants with an excessive buccal angulation in patients with a thin gingival phenotype or inadequate keratinized tissue, may increase the risk of mucosal recession, with consequent exposure of the implant surface. In the case of adjacent implants, failure to provide the proper interimplant distance can increase the risk of “attachment” loss at the interproximal site, creating peri-implant bone defects.

The prevention of such complications is aided by ensuring the stability of the peri-implant tissues through the control of risk factors, in particular smoking, and the absence of residual pockets at the end of periodontal treatment; through correct positioning of the implants the mesiodistal, buccolingual, and apicocoronal directions; through an appropriate choice of implant numbers and implant types; by ensuring minimum interimplant distances; and finally, through proper soft-tissue management, with augmentation performed as needed for functional and esthetic reasons.

In the presence of peri-implant complications, such as bone defects due to peri-implant disease or mucosal recessions on the buccal aspect, various approaches for the treatment and maintenance of compromised implants have been described (Schwartz 2012; Roccuzzo 2011 and 2014b; Zucchelli 2013b; Lang 2001). In case of defects caused by peri-implantitis, treatment proposals vary, ranging from non-surgical and topical pharmacological treatment (Heitz-Mayfield and coworkers 2004; Lang and coworkers 2000), to surgical treatments of a regenerative, resective, or combined nature, with or without implantoplasty. Furthermore, different protocols have been proposed regarding the methods for decontamination of the implant surface.

There is no agreed clinical protocol to determine the need for removing failing implants. A variety of possible clinical situations gives rise to treatment decisions based on individual experience and skill; the available literature consists mainly of case reports, often of purely anecdotal value.

The case presented here is one example of such a clinical situation, with each situation requiring a different approach on a case-by-case basis in terms of both the techniques used and of the surgical sequence. In particular, also as evidenced in the presented case, the correction of peri-implant disease outcomes and the loss of implants frequently require longer treatment times and include many additional steps in order to reach an optimal therapeutic result. Required strategic choices include the number and type of new rehabilitation options aimed at preserving the largest possible volume of reconstructed tissue.

Finally, this case is a clear example of how the reconstruction of soft tissues is often unavoidable to achieve the therapeutic goal and must be performed before or simultaneously with the bone regeneration phase.

Clinical relevance

The decision-making criteria that guide the removal of compromised implants and the protocols to be followed for replacing them with new ones are still difficult to define. However, in case of implant failure, the impact of pathological processes often involves extensive loss of both hard and soft tissues. If the therapeutic choice is to place new implants, the need to rebuild lost (soft and hard) tissues must provide a sequence that, through the reconstruction of soft tissues, improves the healing of the hard tissues and assures their stability in the medium and long term.

Surgical techniques must be used that produce predictable results while reducing, wherever possible, the number of surgical steps and trying to deal with the defects present on adjacent teeth.

6.4 Soft-Tissue Volume Augmentation Using a Connective-Tissue Graft Harvested from the Maxillary Tuberosity

D. Etienne

In 1983, a 51-year-old non-smoking patient was referred for the treatment of moderate chronic periodontitis. At the initial examination, 47% of sites exhibited probing depths of 4 to 6 mm. Periodontal therapy consisted of initial periodontal treatment including oral-hygiene instructions and supra- and subgingival debridement, followed by periodontal surgery to eliminate residual pockets.

Three years following active periodontal therapy, only 8% of sites exhibited residual probing depths of 4 mm, while full-mouth plaque and bleeding scores amounted to 18% and 35%, respectively.

The patient was enrolled in a periodontal maintenance program encompassing regular recall visits every six months, consisting of oral-hygiene instructions, supragingival tooth cleaning, and localized subgingival debridement if needed. The patient also tested positive for a genetic polymorphism of the IL-1 genes (Medical Science System) (Kornman and coworkers 1997).

During the following years, the patient developed endodontic complications, including pulpal necrosis of anterior teeth, which were restored with acid-etched metal/composite-bonded retainers and dentine pins. Vertical root fractures occurred at teeth 36, 37, and 46 (Fig 1), which were subsequently extracted. Tooth 46 was extracted in January 2001 with root separation. The extraction revealed the presence of a deep bony defect on the buccal aspect of the mesial root and a shallow bone defect on the lingual aspect, while the interradicular bone was preserved.

Localized periodontal disease also recurred at teeth 32, 33, and 27, resulting in the loss of tooth 27.

In March 2001, the patient was treated for a myocardial infarction that involved the placement of a stent. The cardiologist’s approval to proceed with implant placement was received in November 2002 (the patient was 70 years old at that time) (Fig 2).

The sagittal scan revealed limited crestal resorption buccally on the mesial aspect of the edentulous ridge (Fig 3).

The clinical situation two years after the extraction of tooth 46 demonstrated the presence of an adequate width of keratinized mucosa, with the mucogingival line in the edentulous space located slightly coronally to that of the adjacent teeth. The alveolar ridge appeared to have a slight horizontal volume deficiency (Figs 4 and 5).

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