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Оглавление3 Soft-Tissue Management Around Tissue-Level Implants
3.1 Soft-Tissue Management at Implant Placement
From the biological point of view, the apicocoronal positioning of an implant, particularly those of tissue-level design, should follow the principle of “as shallow as possible, as deep as necessary” (Buser and coworkers 2004) in order to avoid deep peri-implant probing depths, taking into account the prosthetic and esthetic factors in the area.
This concept has recently been confirmed in a case-control study on 19 patients that evaluated the modifying effect of a deep mucosal tunnel (DMT, ≥ 3 mm) on the induction and resolution phases of experimental peri-implant mucositis (Chan and coworkers 2019). All patients, each with a properly placed tissue-level implant, were assigned either to the test group (DMT, depth ≥ 3 mm) or to the control group (shallow mucosal tunnel, SMT, ≤ 1 mm). The subjects underwent a standard experimental peri-implant mucositis protocol, characterized by an oral-hygiene optimization phase, a three-week induction phase using an acrylic stent to prevent self-performed oral hygiene at the experimental implant, and a three-plus-two-week resolution phase.
The modified plaque index (mPI), gingival index (mGI), and IL-1β concentrations in the peri-implant sulcus fluid were determined over time. Both the mPI and the mGI increased during the induction phase. After normal oral hygiene had resumed, the mPI and mGI resolved towards baseline values in the SMT group, while they diverged in the DMT group. Although plaque accumulation was resolved in the DMT group, the resolution of inflammation was delayed and found to be of smaller magnitude during the first three weeks after resumption of oral hygiene. IL-1β Concentrations were significantly higher in the DMT group at the end of induction and during the resolution phase, corroborating the clinical findings. Removal of the crown and submucosal professional cleaning were needed to revert mGI to baseline values in the DMT group.
The fact that the depth of the peri-implant sulcus influenced the resolution of experimental mucositis raised doubts as to the efficacy of self-performed oral hygiene in scenarios where implants are placed too deeply. Therefore, since the risk of mucositis evolving into peri-implantitis appears to be higher in such clinical situations, clinicians should make every effort to place implants properly—not only for esthetic, but also for biological reasons (Berglundh and coworkers 2018).
It should be noted that, from a clinical point of view, this may be more easily achievable for implants without adjacent teeth, but more challenging if the implant has to be placed between two teeth, particularly if these teeth are periodontally compromised. Figures 1a-b show examples of correct implant positioning. Figures 2a-b show examples of incorrect implant positioning.
Fig 1a The implant was carefully selected and positioned in a periodontally compromised patient so as to present minimal probing depth (time of crown cementation).
Fig 1b Healthy interdental papilla between two tissue-level implants, after removing seven-year-old single ceramic crowns which had been kept in place with provisional cement.
Fig 2a The distal implant was placed at the level of the bone crest without considering the thickness of the soft tissue, resulting in a deep mucosal tunnel.
Fig 2b Residual resin-based cement around the distal Wide Neck Implant. The deep mucosal tunnel does not allow complete removal of the excess cement. Screw-retained restorations would have been preferable in both cases.
The ideal implant position for optimal soft-tissue integration should be planned before removing the teeth. Ridge preservation is one of the treatment options after tooth extraction, particularly in situations where one or more socket walls are missing (Roccuzzo and coworkers 2014c; Mardas and coworkers 2015). The rationale for this approach is that the maintenance of the ridge contour often facilitates subsequent treatment steps and limits the risk of an improper position of the implant collar, creating an ideal soft-tissue seal (MacBeth and coworkers 2017). Figures 3a-i show an example of long-term soft-tissue stability after implant placement following ridge preservation. The correct positioning of an implant, with a shallow peri-implant sulcus, could be particularly difficult in areas where the mucosa is too thick. Here an appropriate flap design is mandatory, especially if cemented restorations are planned. Figures 4a-h show an example of implant positioning in the posterior maxilla where a tissue excess needed to be removed.
Fig 3a Radiograph of a first molar with a severe endo-perio lesion. A large post-extraction bone defect with reduced bone levels near the adjacent teeth was anticipated, and therefore ridge preservation was planned.
Fig 3b After tooth extraction and careful removal of inflamed epithelium around the socket border, the marginal mucosa appeared mobile due to the lack of buccal bone.
Fig 3c Deproteinized bovine bone mineral (DBBM) with 10% collagen (Bio-Oss Collagen; Geistlich, Wolhusen, Switzerland) was inserted to fill the decontaminated socket and covered with a double layer of collagen membrane (Bio-Gide; Geistlich) secured with 4-0 Vicryl (Ethicon; Johnson & Johnson International) resorbable sutures.
Fig 3d After eight weeks of healing, a thick band of keratinized mucosa was visible.
Fig 3e After four months, the dimensions of the ridge were adequate to insert a fixture in the proper position, with no need for further augmentation.
Fig 3f A chemically modified titanium implant was placed (S, WNI SLActive, diameter 4.8 mm, length 12 mm; Institut Straumann AG, Basel, Switzerland).
Fig 3g The soft tissues were circumferentially adapted around the smooth collar of the implant for ideal non- submerged suturing.
Fig 3h Three months after placement, the implant was surrounded by a firm collar of keratinized tissue.
Fig 3i Good stability of the peri-implant soft tissues seven years after placement despite some buccal recession on the adjacent natural premolar.
Fig 4a Part of a panoramic radiograph. Large cyst in the maxillary left sinus. After consultation with an ENT surgeon, who did not suggest any specific treatment, it was decided to place implants without interfering with the sinus.
Fig 4b The left posterior maxilla. The probe used for bone sounding indicated the presence of very thick mucosa in the area of the second molar.
Fig 4c Primary incision lines.
Fig 4d Left posterior maxilla after removal of the excess tissue, which was later used as a graft in the anterior area.
Fig 4e Titanium implant at site 27 with a chemically modified surface (S, WNI SLActive, diameter 4.8 mm, length 10 mm; Institut Straumann AG). The standard implant with a 2.8-mm smooth collar was considered ideal for bringing the margin of the restoration to a more coronal level.
Fig 4f Intraoperative view following the placement of implant 24 (SP, WNI SLActive, diameter 4.1 mm, length 12 mm; Institut Straumann AG). The implant with a 1.8-mm collar was selected to reduce the risk of future soft-tissue dehiscences. The bone concavity on the buccal aspect of the mesial implant is a risk factor for dehiscence.
Fig 4g Autologous bone chips on the buccal aspect of the implant. The connective-tissue graft taken from the posterior area was adapted to protect the bone chips and to increase the width of the crest.
Fig 4h Semi-submerged healing in the anterior grafted area; non-submerged healing with close adaptation of the flap around the collar of the distal implant.
Fig 4i Optimal adaptation of the soft tissues around both implants six weeks after implant placement.
Fig 4j Solid abutments, 4 mm in height, connected eight weeks after implant placement.
Fig 4k Four-unit cemented metal-ceramic bridge in situ.
Fig 4l One-year follow up. Healthy peri-implant soft tissues with minimal probing depth (< 4 mm) and no bleeding after removing the provisionally cemented ceramic bridge.
Fig 4m Radiograph at the five-year follow-up. Stable interproximal bone levels.
One of the challenges in optimal flap design around non-submerged implants is the circumferential closure around the implant collar, especially when the soft tissues present anatomical irregularities. Figures 5a-k show an example of soft-tissue management for non-submerged tissue-level implants in the posterior maxilla with an irregular soft-tissue morphology.
Fig 5a Preoperative situation.
Fig 5b Incision placed slightly palatally to move keratinized tissue onto the buccal side.
Fig 5c Two wide-neck implants placed at sites 26 and 27 (SP, WNI SLActive, diameter 4.8 mm, length 10 mm; Institut Straumann AG).
Fig 5d Incision on the distal portion of the palatal flap.
Fig 5e The pedicle flap was rotated counterclockwise.
Fig 5f Pedicle inserted between the two implants.
Fig 5g The pedicle was adapted with a 4-0 Vicryl vertical mattress suture between the 2 implants.
Fig 5h Final suture, distally to the distal implant.
Fig 5i Preoperative occlusal view.
Fig 5j Postoperative occlusal view.
Fig 5k Periapical radiograph at eighteen months after implant placement. Favorable interproximal bone levels.
Creating an optimal flap for ideal transmucosal healing becomes even more difficult if no keratinized mucosa is present at all. In these circumstances, a free gingival graft may be advised, especially if bone regeneration is required, as discussed in Chapter 4.1.
Often, a small quantity of keratinized tissue will be sufficient to create a soft-tissue cuff around the implant collar, provided the tissue is properly surgically managed. Figures 6a-I show an example of soft-tissue management around a tissue-level implant in conjunction with bone regeneration in a case where there does not appear to be any keratinized tissue available.
Fig 6a Preoperative view of site 46, at the end of orthodontic treatment. Limited crestal width and no keratinized mucosa.
Fig 6b-c Once the implant was placed (S, SLA, diameter 4.1 mm, length 12 mm; Institut Straumann AG), the dehiscence on the facial bone was covered with autologous bone and a DBBM graft.
Fig 6d Resorbable collagen membrane prepared with a punched hole, placed over the graft, and secured with a healing cap.
Fig 6e-f The mesial papilla rotated 90° counterclockwise and sutured to the distal papilla to provide a wide band of keratinized tissue buccally to the implant.
Fig 6g-h e-PTFE sutures, buccal and occlusal views.
Fig 6i Early healing (at six weeks). A new mucogingival line is already evident.
Fig 6j Fifteen months after implant placement, facial view. Ideal contour of the soft tissues thanks to bone grafting and papilla rotation at the time of implant placement.
In many circumstances, poor implant placement may result in restricted access for proper oral hygiene and increase the risk of mucosal inflammation. Plaque accumulation at implant sites causes a more pronounced inflammatory response compared to natural teeth (Berglundh and coworkers 2011). Indeed, even though the evidence is limited, there is a strong common perception that properly placed implants do not present biological complications as frequently as poorly placed implants.
Apart from the prosthetically driven position, a wide band of non-mobile, keratinized mucosa, a correct peri-implant sulcus, and a thick tissue phenotype might seem desirable, if not essential, for reducing the incidence of tissue inflammation and long-term complications around implants.
3.2 Soft-Tissue Management Before Implant Placement
On the occasion of the 2017 World Workshop, Hämmerle and Tarnow (2018) reported that a significant amount of controlled prospective studies with medium-size patient samples indicated that thin soft tissue around implants leads to increased peri-implant marginal bone loss compared to thick soft tissue. Most of the data, however, were published by one group of researchers.
Linkevicius and coworkers (2009) placed 46 implants in 19 patients. The implants were divided into two groups related to soft-tissue thickness. At the one-year follow-up, the marginal bone loss at the implants in the thin-tissue group was on the order of 1.5 mm, compared to only 0.3 mm in the thick-tissue group.
In addition, the same investigators analyzed the effects of buccal soft-tissue thickness on marginal bone-level changes in 32 patients. They found a significant correlation between soft-tissue thickness and bone loss, with thin soft-tissue sites presenting more bone loss (0.3 mm versus 0.1 mm) at the one-year follow-up.
That thin soft tissue leads to increased marginal bone loss was confirmed in another recent study (Linkevicius and coworkers 2015). In addition to the thin-tissue and thick-tissue groups, the investigators followed a third group of about 30 patients whose thin soft tissue was augmented by grafting at the time of implant. The resulting bone loss was not different from that in thick soft-tissue group. These findings seem to indicate that adequate soft-tissue thickness benefits the stability of the peri-implant bone levels.
In another study, Puisys and Linkevicius (2015) concluded that, since significantly less bone loss can occur in naturally thick soft tissue than in patients with a thin tissue phenotype, augmenting the tissue could be the way to reduce crestal bone loss.
Based on the observation that significantly less bone loss occurs around implants placed in thick tissue phenotypes compared to thin phenotypes, clinicians may be encouraged to augment thin soft tissue before or during implant placement in order to facilitate crestal bone stability. Figures 7a-i show an example of this treatment approach in the posterior mandible of a 63-year-old woman.
Fig 7a Panoramic radiograph of the edentulous sites 46 and 47. There is barely enough bone available for implant placement above the mandibular canal.
Fig 7b Edentulous area, buccal view. Very shallow vestibule and absence of keratinized mucosa.
Fig 7c Edentulous area, occlusal view. Very thin crest.
Fig 7d Free gingival graft harvested from the palate sutured above a split-thickness flap in the area where the implants are planned.
Fig 7e Graft sutured with 4-0 Vicryl, occlusal view
Fig 7f At three months, a full-thickness flap was raised lingually and buccally for placing the implants. Thicker keratinized tissue on both sides of the flap.
Fig 7g At the time of the final impression, occlusal view. Both implants are surrounded by a thick collar of keratinized tissue, that creates an effective barrier that protects the peri-implant structures.
Figs 7h-i Clinical and radiographic views of the screw-retained ceramic crowns at 6 years. Prosthetic procedures: Dr. Nicola Scotti – Torino, Italy
From a clinical perspective, the presence of a wide band of keratinized tissue facilitates the transmucosal healing of dental implants, even in cases where bone regeneration is required, as it allows the creation of a thick soft-tissue cuff around the collar of the implant. Figures 8a-l show an example of this treatment approach in the posterior mandible of a 57-year-old woman, for whom horizontal bone regeneration was needed in conjunction with implant placement.
Fig 8a Preoperative view. Bone atrophy associated with the presence of very thin mucosa, with almost no keratinization.
Fig 8b Two free gingival grafts sutured in the area where implant placement and bone regeneration was planned.
Fig 8c Three months after soft-tissue augmentation. A thick band of keratinized tissue was present on the lingual and buccal aspects of the full-thickness flap.
Fig 8d Implants at sites 35 and 37 (S, RN, diameter 3.3 mm, length 10 mm, and S, RN, diameter 4.8 mm, length 10 mm; Institut Straumann AG) with a large dehiscence-type bone defect on the buccal aspect.
Fig 8e Guided bone regeneration with autologous bone in contact with the implant surface, followed by a layer of deproteinized bovine bone mineral (DBBM). Resorbable collagen membrane adapted around the implants to stabilize the graft.
Fig 8f Sutures for transmucosal healing. Ideal soft-tissue seal around the collar of the implants thanks to the preliminary soft-tissue augmentation.
Fig 8g At the time of delivery of the final prosthesis, occlusal view.
Fig 8h Three-unit ceramic bridge delivered and secured with temporary cement.
Figs 8i-j One-year clinical and radiographic follow-up. The prosthesis was removed to double-check the condition of the soft tissues and later then reinserted using definitive cement.
Figs 8k-l Ten-year follow-up. Minor pigmentation of the ceramic crown on the buccal side. Healthy peri-implant soft tissue with minimal probing depth.
Several studies have argued the use of various techniques for vertical ridge augmentation in cases of severe atrophy of the alveolar ridge, using either non-resorbable or resorbable membranes supported by a space-making device or a titanium mesh (Esposito and coworkers 2008; Fontana and coworkers 2011; Roccuzzo and coworkers 2017a).
All these studies also showed that the use of a barrier device is a technique-sensitive procedure and subject to surgical complications (Jepsen and coworkers 2019). One of the main reasons for GBR failures is related to exposure of the barrier membrane, leading to bacterial contamination of the surgical area and infection and thereby compromising the regeneration outcome (Sanz and coworkers 2019). Even though there have been no specific studies on this matter, it might be suggested that membrane exposure, especially during the first four weeks postoperatively, may be higher in patients with very thin mucosa, or without keratinization, or with scar tissue. In specific circumstances, it is therefore reasonable to consider optimizing the quantity and quality of the soft tissue before hard-tissue regenerative procedures are carried out.
Figures 9a-p exemplify this approach in the mandible of a 63-year-old patient, a dentist and current cigarette smoker. He had previously received an implant at site 35, but it had recently fractured. After surgically removing the fractured implant, vertical bone augmentation was required, as the bone was not high enough to place an implant above the mandibular canal. The examination of the local soft tissue revealed minimal keratinized mucosa and the presence of scar tissue as a result of previous surgery. To reduce the risk of soft-tissue dehiscence and of exposure or infection of the area following GBR, the patient was advised that preliminary soft-tissue augmentation was required prior to any attempt at vertical bone regeneration.
Figs 9a-c Surgical removal of the fractured implant.
Figs 9d-e After three months, site 35 presented with minimal keratinized mucosa and scar tissue, considered not to be ideal in view of the planned vertical bone augmentation.
Fig 9f Free gingival graft sutured on the periosteum after elevating a split-thickness flap, with 4-0 Vicryl.
Fig 9g Four months after soft-tissue augmentation, lateral view.
Fig 9h Custom-made Ti-mesh filled with autologous bone combined with DBBM and secured with two screws to contain and protect the bone graft. The presence of thick mucosa reduced the need for a collagen membrane.
Fig 9i Flap closed without tension despite coronal advancement and adapted to completely cover the augmented area. The flap was stabilized with Vicryl 3-0 horizontal mattress sutures at the apical aspect and Vicryl 4-0 multiple single interrupted sutures at the far coronal aspect.
Fig 9j Two weeks after the surgery. The flap had healed well, and the sutures could be removed.
Fig 9k Clinical view six months after regeneration surgery. Optimal healing.
Figs 9l Radiographic view of the augmented area before implant placement surgery.
Fig 9m After removal of the Ti-mesh, two Straumann Tissue Level implants were placed at sites 35 and 36 (SP, RN, diameter 3.3 mm, length 8 mm, and SP, RN, diameter 4.1 mm, length 6 mm; Institut Straumann AG).
Fig 9n Sutures applied for optimal non-submerged healing.
Fig 9o Three months after surgery. Implants surrounded by a thick cuff of healthy keratinized mucosa. The impressions could now be taken for the final restoration.
Fig 9p Six months after implant placement, the probe indicated a shallow sulcus with no signs of inflammation. Prosthetic procedures: Dr. Walter Gino – Torino, Italy
Based on the conclusions of the 2017 World Workshop, namely that a significant amount of controlled prospective studies indicated that thin soft tissue around implants leads to increased marginal bone loss compared to thick soft tissue, clinicians may be encouraged to create ideal soft-tissue conditions before placing implants. Mucogingival surgery may be indicated particularly in patients with thin soft tissue and no keratinization. Each of the two steps of this approach is relatively easy to perform. However, the patient will have to accept the discomfort of two separate interventions not less than a month apart from each other.
Even though recent publications provided guidelines for decision-making if the clinician considers autologous soft-tissue grafting to promote peri-implant health or preserve marginal bone levels at implant sites with insufficient soft-tissue dimensions (Thoma and coworkers 2018a; Giannobile and coworkers 2018), the ideal clinical solution should be individually determined and should represent the results of a proper patient-clinician discussion.
3.3 Soft-Tissue Management During Supportive Care
Recent evidence has shown that favorable long-term implant survival rates can be achieved even in periodontally compromised patients, provided they are placed on an individually tailored supportive peri-implant/periodontal therapy (SPT) program, which includes continuous evaluation of the occurrence and the risk of disease progression (Roccuzzo and coworkers 2014a).
It has been suggested that implant therapy today must not be limited to surgery/restoration, but should also include an SPT program tailored to the patient’s risk profile. Data indicate a minimum recall interval of five to six months (Monje and coworkers 2019). However, in terms of interventions to prevent peri-implant biologic complications, it is unclear at what point mucogingival surgery may be indicated to improve peri-implant soft-tissue conditions.
According to the 2017 World Workshop (Caton and coworkers 2018), peri-implant mucositis is characterized by bleeding on probing and by visual signs of inflammation; there is robust evidence that it is caused by plaque. Peri-implantitis was defined as a plaque-associated pathological condition occurring in the tissue around dental implants, characterized by inflammation in the peri-implant mucosa and subsequent progressive loss of supporting bone. Peri-implant mucositis precedes peri-implantitis, but can be reversed with measures aimed at removing plaque.
Based on these considerations, every effort should be made to motivate the patients and to facilitate their ability to maintain plaque control both at implants and teeth, aiming for a low full mouth plaque score. The 6th ITI Consensus Conference (Heitz-Mayfield and coworkers 2018a) recommended the provision of individualized supportive care according to the patient’s needs and risk profile. This should include performing oral hygiene, removing biofilm, monitoring oral health, and reducing modifiable risks.
From this point of view, anatomical aspects must be considered in attempting to intercept those site-specific conditions that constitute a local risk factor for the development of peri-implantitis, such as deep peri-implant pockets, the presence of a frenulum, or the lack of keratinized attached mucosa. In these circumstances, SPT may also include a surgical modification of the soft tissue to facilitate plaque control, as demonstrated in recent studies.
In a controlled clinical, immunological, and radiographic study, Büyüközdemir Aşkın and coworkers (2015) examined the necessity for peri-implant keratinized tissues for effective maintenance. Forty patients with inadequate keratinized tissue were assigned to two groups: free gingival grafting (FGG) was performed in one group, while the other group received standardized maintenance with no additional surgery. Clinical parameters, peri-implant sulcular fluid (PISF) volumes, PISF Interleukin-1β (IL-1β) concentrations, and bone loss were analyzed. Significant improvements in clinical and immunological parameters were noted only for the FGG group throughout the study period. The authors concluded that FGG performed around implants lacking keratinized tissue is a reliable method, leading to significantly improved clinical and inflammatory parameters.
Oh and coworkers (2017) evaluated clinical and radiographic outcomes following a free gingival graft around implants with limited keratinized mucosa, compared to oral prophylaxis alone. Their prospective study investigated 41 implants with a lack of keratinized mucosa in 28 subjects: 14 patients received an FGG followed by prophylaxis and 14 subjects received oral prophylaxis alone. The results of the study indicated that the gingival index (GI) and crestal bone loss was significantly lower in the FGG group than in the control group. The authors concluded that a free gingival graft for implants exhibiting a lack of keratinized mucosa is a valid treatment option that reduces mucosal inflammation and maintains crestal bone levels in the short term.
These preliminary results seem to confirm the beneficial role of keratinized tissue for maintaining healthy conditions around implants. Peri-implant mucogingival surgery may therefore be considered an essential part of SPT in specific circumstances.
The contribution of a frenulum to the etiology of a soft-tissue dehiscence around natural teeth remains controversial. Cortellini and Bissada (2018) reported it to be (although at low levels of evidence) one of the conditions that might contribute to the development of gingival recession, as a frenulum may compromise the efficacy of oral hygiene.
Nothing was mentioned during the 2017 World Workshop regarding the possible negative impact of a frenulum attached to an implant.
Nevertheless, from a clinical point of view, treatment may be indicated in cases where a marked frenulum attaches to thin peri-implant mucosa and there is a risk of development of progressive recession. Moreover, due to the lack of a tight soft-tissue seal, optimal plaque control may be more difficult to achieve. Finally, in some circumstances, these situations lead patients to report brushing discomfort. Figures 10a-f show an example of soft-tissue grafting performed during SPT to facilitate proper plaque control in an area with a frenulum, lack of keratinized mucosa, and a shallow vestibulum.
Fig 10a-b Radiographic and clinical view of two implants (SLA S, diameter 4.1 mm, length 12 mm, and S, diameter 4.1 mm, length 10 mm; Institut Straumann AG), placed two years previously into a thin ridge, presenting with an inferiorly attaching frenulum facially to implant 26. Treatment was indicated to facilitate plaque control and to prevent further progression of the recession.
Fig 10c-e A trapezoidal split-thickness flap was elevated at the implant site. A connective-tissue graft was adapted and placed in a fully submerged approach for optimal blood supply.
Fig 10f Nine years after the surgical correction. Plaque control was improved around the treated mesial implant, while the soft-tissue dehiscence had increased on the distal implant, which had not received further treatment. The surgical trauma, the shallow vestibule, the lack of keratinized attached mucosa or a thin buccal bone plate at the crestal level may have contributed to the formation of the dehiscence/recession at the most distally located implant.
While a pocket depth of 5 mm with bleeding on probing around a tooth is, by definition, pathological, the same cannot be said if found around an implant. Around dental implants, the AAP/EFP workshop suggested that it is not currently possible to determine what constitutes a physiological pocket depth (Schwarz and coworkers 2018; Berglundh and coworkers 2018). It is hard to clearly assess, during supportive care, when a peri-implant pocket should be considered excessive and would require treatment.
Two recent studies have tried to investigate the correlation between peri-implant pocket depths and bleeding.
Merli and coworkers (2017) analyzed 92 implants and found bleeding in 39% of the sites. The odds ratio increased by 1.81 (95%-CI, 1.47–2.23; p < 0.0001) for each 1-mm increment in pocket depth. The authors concluded that the probability of peri-implant bleeding on probing was positively associated with peri-implant pocket depth.
Similar findings were reported by Farina and coworkers (2017), who tried to identify factors associated with the probability of peri-implant bleeding on probing in 112 patients, with data related to 1,725 peri-implant sites. The results of the study indicated that the odds ratio increased by 1.6 for each 1-mm increment in pocket depth. Since the deeper the pocket, the higher the probability of bleeding, clinicians should make every effort to control pocket depths around implants during supportive care, even in the absence of any evidence of biological complications.
Moreover, in selected circumstances, surgical modification of the soft tissue is advisable to reduce the depth of the peri-implant mucosal tunnel, particularly if concomitant bleeding is found, as in the case of the 64-year-old man presented in Figures 11a-f.
Fig 11a Implant 27, placed nine years previously, palatal view. 13-mm pocket and bleeding on probing. Implant 26 had been placed recently and not yet been loaded. The deep pocket at implant 27 should have been addressed before placing the new implant, or at least at the same time.
Fig 11b Gingivectomy to eliminate the excessive soft tissue.
Fig 11c Application of a periodontal dressing.
Fig 11d Early healing six weeks after surgery.
Fig 11e Palatal view of implant 27, presenting with 3-mm probing depth and no bleeding.
Fig 11f Panoramic radiograph. Ideal peri-implant bone levels around the distal implant at the fifteen-year follow-up.
The main objectives in treating peri-implantitis are:
• decontamination of the implant surface
• removal of infected/inflamed tissue
• creation of a soft-tissue architecture to facilitate oral hygiene.
To achieve this, it is often necessary to elevate a full-thickness flap to remove the granulation tissue resulting from the local inflammation and to decontaminate the implant surface. Depending on the configuration of the defect, a reconstructive approach is often preferred, with or without a membrane. One of the possible negative outcomes of this approach is the creation of a peri-implant soft-tissue dehiscence (Heitz-Mayfield and coworkers 2018a; Roccuzzo and coworkers 2017a). If such a dehiscence raises esthetic concerns, particularly in patients with high esthetic expectations, additional interventions may be required (see Chapter 5.2, Fig 3).
To reduce the need for multiple surgery, particularly if a soft-tissue dehiscence is already present, the surgical treatment of peri-implantitis may be accompanied by the application of a connective-tissue graft (CTG) (Roccuzzo and coworkers 2016). Figures 12a-y illustrate a case where the surgical treatment of a peri-implantitis defect was associated with the application of a CTG.
Fig 12a-b Radiographic and clinical view of a hollow-screw implant placed in November 1994, presenting with a pocket and a soft-tissue dehiscence.
Fig 12c After raising a full-thickness flap, the granulation tissue was removed with a titanium brush and curettes.
Fig 12d 24% EDTA applied for two minutes for decontamination.
Fig 12e Connective-tissue graft, taken from the maxillary tuberosity and properly trimmed, adapted over the defect.
Fig 12f Flap sutured with 4-0 Vicryl to completely cover the connective-tissue graft.
Fig 12g Seven-year follow-up. No signs of inflammation. The soft-tissue recession was reduced.
Fig 12h Minimal probing depth and no bleeding at the nine-year follow-up visit.
Fig 12i Twenty-five years after implant placement. The situation is still stable and free from signs of inflammation.
Recently, a reduced width of keratinized tissue around dental implants has been considered a risk indicator for the severity of peri-implant mucositis (Grischke and coworkers 2019) even in highly compliant, periodontally healthy patients. Based on this observation, in cases of peri-implant mucositis associated with insufficient keratinized tissue, a soft-tissue graft may be indicated to reduce the risk of recurrence. Figures 13a-y illustrate a case where the treatment of severe peri-implant mucositis was accompanied by the application of an FGG graft to improve the quality of the peri-implant soft tissue and to improve the chances of successful long-term maintenance.
Fig 13a Mucositis around an implant (SLA S, diameter 4.1 mm, length 8 mm; Institut Straumann AG) placed more than ten years previously.
Fig 13b The crown and abutment were removed to provide access to the inflamed area.
Fig 13c The treatment consisted of careful debridement and gentle cleaning of the area with titanium curettes and an ultrasonic device with a PTFE-coated tip.
Fig 13d An FGG was harvested from the palate and perforated with a 4-mm biopsy punch.
Fig 13e Precisely adapted FGG around the smooth collar of the implant.
Fig 13f Graft secured by means of 5-0 Vicryl sutures.
Fig 13g Six months after treatment.
Fig 13h New screw-retained ceramic crown in situ.
Dentists should focus on more than just the implants and prosthetic restorations to achieve long-term clinical success.
Patients must be strongly motivated to adhere strictly to SPT and should be made to understand that supportive care is a key factor in enhancing the long-term outcome by controlling reinfection. Although the topic remains controversial due to a lack of proper scientific evidence, there is still enough clinical evidence that adequate keratinized tissue and vestibular depth may positively impact the health of the peri-implant mucosa. Furthermore, soft-tissue augmentation around implants in specific clinical situations may be of major help in ensuring long-term stability. Only if both the clinician and the patient understand the importance of a custom-planned SPT program—which may also include mucogingival surgery—can the risk of biological complications be reduced to a minimum.
