1. INTRODUCTION
In recent years, the use of dental implants has increased. Complications can lead to esthetic and functional defects if the necessary surgical steps for tissue reconstruction are not followed1. Patients expect the outcome to be the most similar to their natural dentition. The increased complexity of implant treatment2 is related to the need to achieve harmony between white and pink esthetics.
In white esthetics, a restorative material can be manipulated to mimic the adjacent teeth. On the other hand, pink esthetics will depend on the architecture of soft and hard tissues. The transition zone represents the area between the prosthetic crown and the implant3. The complicating factor in implantology is obtaining pink esthetics in areas that have bone and gingival (mucosal) deficiencies. The treatment plan has to include possible grafting procedures to maintain the tissue architecture or recover what was lost4.
Taking into account an individual’s characteristics, soft and hard tissue grafting can be performed before, simultaneously, or after implant placement5. Soft tissue defects present a varied etiology. The cause of the defect determines the approach to correct it.
Defects caused by limited bone availability, gingival biotype, and altered dental position are simpler to resolve before implant placement. Tissue defects caused by implant mispositioning may require implant removal, tissue regeneration, and placement of another implant in the proper three-dimensional(3D) position.
OBJECTIVES
At the end of the chapter the reader should be able to:
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Understand the techniques needed to improve peri-implant tissue.
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Determine the appropriate treatment(s) for tissue changes.
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Determine the appropriate time for grafting and implant placement.
2. SCIENTIFIC BACKGROUND
Correction of peri-implant esthetic defects (Figs 01A–C) should be performed only after the cause has been determined. In fact, prevention of defects is more predictable; however, it is possible to correct peri-implant defects at the time of reopening or with the prosthesis in place6.
01. A–C Soft tissue defects peri-implant (A). Comparison between contralateral teeth shows complications that are difficult to treat (B, C).
Changes in the architecture, color, contour, or texture of peri-implant tissues may represent complications around implants and require treatment. Surgery is often unable to address these defects alone and should be combined with restorative and orthodontic procedures, especially when there is loss of interproximal tissue (Figs 02A–F). Correction of these defects is necessary to achieve adequate quantity and quality of peri-implant tissues. Failures usually occur due to incorrect placement of the implant, lack of gingival and bone tissue grafts, or because of altered healing after surgery6.
02. A–F Patient with a gummy smile and history of multiple implant losses on tooth 21. The implant was clinically stable but with recession of the peri-implant margin and papillae (A–C). Due to previous implant loss, the patient opted to try to maintain the implant at first. The limitations of this case were properly explained. A multidisciplinary approach was planned and the first surgical step to increase tissue thickness began (D–F).
Bone grafts have been extensively used in implant dentistry to allow for implant placement in the correct position7,8 or correct minor peri-implant defects9. Thus, the grafting procedure has great value when attempting to obtain a favorable peri-implant esthetic.
Similarly, soft tissue grafts aim to improve the transition zone for more favorable results. Free gingival grafts may be indicated for volume increase, vertical gain, and the creation of a band of attached gingiva6.
Corrections to the ridge or around implants can be classified according to the indicated time for implant placement. Thus, regenerative procedures can be performed preventively, before implant placement, at the same time as surgery, or after implant osseointegration.
2.1. CORRECTIVE PROCEDURES BEFORE IMPLANT PLACEMENT
Changes in tissue architecture represent horizontal, vertical, or combined defects. The predictability of regeneration will depend on the interproximal and buccolingual remaining bone structure. Orthodontic or surgical procedures may be necessary.
2.1.1 ORTHODONTIC TREATMENT
Implant placement is difficult in patients with dental misplacement (Figs 03A–L). In many cases, lack of space between teeth, a narrow interocclusal space, and excessive buccal or palatine displacement of neighboring teeth prevent implant placement in the proper position. If this type of dental malposition is present, orthodontic treatment is necessary to allow the implant to be placed in the correct position10.
03. A–L Patient with a history of trauma in the anterior region of the deciduous dentition, which resulted in poor dental positioning (A). Orthodontic treatment repositioned the teeth in the maxillary arch and tractioned the impacted tooth (B–I). After orthodontic movement and traction of tooth 12, loss of the mesial papilla and absence of adequate prosthetic space on tooth 11 (J–L) were noted. These changes are most easily diagnosed during treatment, when professionals from different specialties directly participate in treatment. Orthodontic treatment: Dr Deise Cunha.
Controlled orthodontic movement may promote vertical bone growth, while slow extrusion of a tooth combined with occlusal wear can prevent occlusal trauma11. A thick gingival biotype maximizes the results.
In the past, orthodontic extrusion was used on a compromised tooth to position the buccogingival margin at least 1 mm coronal to the contralateral tooth. After extraction and rehabilitation with implants, the same amount of buccal recession was expected12. Maintenance or indication for extraction will depend on root shape, dental and periodontal condition, remaining bone structure, and prosthetic planning. If an extraction or any other surgical procedure involving the interproximal tissue is necessary, a minimum of 4–8 months must be allowed to stabilize the newly formed bone tissue13.
Currently, orthodontic extrusion is recommended when there is loss of papillae or extensive periodontal defects (Figs 04A–U). If there is gingival recession of up to 3 mm in the compromised tooth, a minimally invasive approach can be performed to reposition the margin coronally at the time of implant placement. The combination of optimal implant positioning, use of a slightly exposed connective tissue graft, and manufacture of a provisional prosthesis with concave subgingival profile will improve gingival level14 (Figs 05A–F and 06A–F).
04. A–U Patient with a history of chronic trauma on tooth 11 with painful sensitivity and presence of buccal fistula (A, B). Exploratory surgery was performed and a dye used to diagnose the presence of an oblique fracture. Extensive buccal, mesial, and distal bone loss was detected (C–E). After discussing the treatment options with the patient, they opted for an attempt to maintain the tooth through slow orthodontic extrusion to improve the interproximal tissue condition (F). If the dental condition was poor after the orthodontic therapy, the patient agreed to undergo extraction and implantation. The tooth was slowly extruded and a considerable bone increase occurred in the interproximal region (G–P). Tomographic aspect before and after orthodontic extrusion (Q, R). Note the improvement in the condition of the buccal bone and limited amount of periodontal attachment at the end of therapy. The patient opted to keep tooth 11 and its rehabilitation with a ceramic crown (S–U).
05. A–F Ten-year follow-up of the previous case where maintenance of the interproximal papillae can be noted; after this period, the root presented a buccal fracture (A–C). The tooth was carefully removed to maintain the crown that would serve as a temporary tooth (D). The implant was placed in the ideal 3D position and the buccal region was grafted with biomaterials and connective tissue grafts (E, F).
06. A–F Implant stability in the socket was 50 N; a provisional with an undercontour on the cervical was manufactured from the crown of tooth 11 (A–C). Postoperative follow-up, where it was possible to note an increase in heightof approximately 2 mm (D–F). The complete surgical staging is presented in Chapter 8. Orthodontic procedure: Dr Deise Cunha; restorative procedure: Dr Bianca Vimercati; surgical procedure (implant and grafts): Dr Fausto Frizzera.
2.1.2. SURGICAL PROCEDURES FOR BONE IMPROVEMENT
The use of grafts is recommended when it is not possible to place implants in the correct position; this may occur in severely resorbed ridges, posterior regions of the maxilla with maxillary sinus pneumatization, or in post-extraction sockets with severe bone defects and poor remaining bone structure7,15,16. In such cases, a healing period after grafting (4–8 months depending on the defect, type, and graft) is necessary before the implant is placed (Figs 07A–G to 12 A–E).
07. A–G Region of tooth 22 with tissue deficiency in thickness (A). The bone defect (B) was treated with a block bone graft removed from the retromolar region, adjusted, and fixed with a screw (C). The spaces between the block and the receiving area were filled with autogenous particulate bone (D) and the grafted area was covered with a membrane. Postoperative aspect after 8 months with implant and healing abutment in place; note the volume increase obtained (E). Frontal and sagittal views of the use of the autogenous block graft (F, G). Surgical procedure: Dr Jamil Shibli.
08. A–L The region of tooth 22 was previously grafted; the patient reported having received a fresh and frozen homogenous bone graft (A, B). A flap was created to remove the fixation screw (C) and install the implant; note the appearance of the grafted tissue as it is different from the patient’s native bone (D). Postoperative aspect 6 months after the implant was installed (E), soft tissue contour (F), and proof of the metal infrastructure (G); rehabilitation was completed and the patient had no complaints. Three years later, the patient returned complaining about a whitish area around the implant. Clinically, there was evidence of bone tissue exposure (H). The necrotic fragment was removed. This event was correlated with the absence of remodeling, vitality, and vascularization of the homogeneous bone graft (I, J). Frontal and sagittal views of the use of the homogeneous graft in a block (K, L). Surgical procedure: Dr Samy Tunchel and Dr Jamil Shibli.
09. A–H A patient with ectodermal dysplasia reported that no teeth had erupted in his mouth and could not use removable dentures (A). Absence of teeth formation led to the nondevelopment of the ridge and consequent severe atrophy of the maxillary bones (B, C). Before implant placement, bone grafting with xenograft material was planned using bilateral maxillary sinus elevation and thick bone grafting in the region of the canine eminence (D–F). The procedure was started by collecting blood to produce L-PRF to aid soft tissue healing (G, H).
10. A–E A total flap covering the maxilla was created note the limited amount of tissue (A, B). The maxillary sinus was lifted bilaterally and filled with inorganic bovine bone particles (C–E).
11. A–I The canine eminence was perforated bilaterally and received the xenograft bone to increase thickness; the bone graft was covered with a resorbable collagen membrane (A–F). On the left, the membrane was fixed with titanium tacks; on the right, this fixation was not performed because the bone tissue was very thin and there were microfractures that prevented its fixation. The L-PRF membranes were positioned in the regions with these microfractures and over the collagen membranes to enhance healing (G). Postoperative images after 1 (H) and 7 (I) months when graft exposure was not verified.
12. A–E Tomographic aspect of the grafted region; note that the region that received membrane fixation showed better results after graft incorporation. In the canine eminence regions, it was possible to place the implant in the correct position, although it requires additional bone grafting. In the maxillary sinus regions, it was possible to obtain a satisfactory result in only one surgery (A–C). Frontal and sagittal views of the xenograft and membrane stabilized with tacks (D, E). Surgical procedure: Dr Fausto Frizzera and Dr Judith Ottoni.
Bone grafts can be used during implant placement to correct bone defects or fill gaps between implants and post-extraction alveolar bone walls17 (Figs 13A–F)
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