TISSUE ARRANGEMENT Implantology course
Plan
1. Introduction
2. Pre-implant arrangement of soft tissues
2.1. Composition of implant soft tissues
2.2. Differences between periodontium/tooth and periodontium/implant
2.3. Role of keratinized gingiva
2.4. Soft Tissue Management Techniques
2.4.1. Subtractive surgery
2.4.1.1. Frenectomy
2.4.1.2. Vestibuloplasty
2.4.2. Additive mucosal surgery
2.4.2.1. Epithelial-connective tissue graft
2.4.2.2. Conjunctival graft
2.4.2. Pre-implant arrangement of hard tissue
2.4.2.1. Bone reconstruction materials
2.4.2.2. Pre-implant bone management techniques
2.4.2.2.1. Vertical Techniques
2.4.2.2.2. Horizontal techniques
Conclusion
Bibliography
- Introduction
In implantology, overall esthetic satisfaction is highly dependent on the appearance of the surrounding soft tissues and the cosmetic characteristics of the prosthetic restoration. The success of dental implants depends largely on the quality and quantity of bone available in the recipient site. Multiple surgical strategies and techniques have been used.
TISSUE ARRANGEMENT Implantology course
- PRE-IMPLANT SOFT TISSUE ARRANGEMENT
Typically, the pre-implant stage is more reserved for bone reconstruction of the site.
The quality and volume of the peri-implant soft tissues will play a very important role in achieving the aesthetic objectives of the prosthetic restoration and the durability of the result.
2.1.Composition of implant soft tissues
Peri-implant soft tissues consist of:
- A keratinized oral epithelium that reaches the gingival crest and extends into
- An intrasulcular epithelium and
- A junctional epithelium,
All of these structures are supported by connective tissue in contact either with the tooth or with the implant.
- Differences between periodontium/tooth and periodontium/implant
TISSUE ARRANGEMENT Implantology course
Although there is general agreement that the presence of attached, keratinized gingiva around implants is desirable, there is no consensus that it would be absolutely necessary to restore it if it were to be lacking.
However, Newman and Flemming in 1988 observed that when an implant emerges in an attached keratinized mucosa, maintenance is easier and the peri-implant soft tissues are more resistant to mechanical aggression than when they emerge within a non-keratinized and mobile alveolar mucosa.
- Role of keratinized gingiva
The keratinized and attached gingiva around implants has several roles as well as when it is present around a tooth. Its main functions:
- Prevent tissue collapse around the emergence of the implant which could lead to aesthetic and functional deficit,
- Make it easier to take fingerprints,
- Have adequate height and thickness of gingiva to protect the implant and the peri-implant sulcus,
- Allow for a firm crimp and connective tissue attachment around the implant to protect it from infection and prevent it from spreading apically
- prevent recession of the marginal gingiva which is of interest for the long-term maintenance of adequate aesthetics.
- Its presence also eliminates any excessive movement of the free gingiva which could lead to a rupture of the connective attachment and subsequently a gateway for bacteria.
- Finally, we can highlight its essential role in resistance to trauma due to brushing.
2.4. Soft Tissue Management Techniques
The performance of autogenous soft tissue grafts has marked the last 50 years. The main surgical procedures aim to:
- Provide keratinized tissue (in height and/or thickness),
- Thicken existing tissues or
- Cover root denudations.
These techniques were mainly studied around teeth and were then transposed to implants.
TISSUE ARRANGEMENT Implantology course
- Indications
- Clinical situations that present a significant deficit of keratinized tissue, this clinical situation is most often found at the level of the edentulous posterior mandibular sectors in patients with a fine tissue phenotype,
- It is advisable to strengthen the gingiva around the implants supporting the implant prostheses if the periodontium is thin or the attached gingiva is absent.
When are they made?
The development of peri-implant soft tissues can be carried out at different stages of implant treatment; development can be carried out before implant placement. For example, during a dental extraction, it is possible to graft a buried connective tissue to thicken the gingival tissue, either:
- when placing implants,
- when excavating implants or
- after placement of the prosthetic superstructure
2.4.1. Subtraction surgeries
Situations in which the edentulous ridges present a defect by excess are rarer than deficits 2.4.1.1. Frenectomy
Objective :
To limit muscle traction on the gum, this procedure mainly involves the maxillary and mandibular medial labial frenums, but also the lateral frenums and the lingual frenum.
Indication
Hyperplastic frenulum and/or causing traction and significant mobilization of gingival tissues.
2.4.1.2. VestibuloplastyIt consists of:
- increasing the depth of a shallow vestibule, in order to remove tension at the marginal gingiva,
- Achieving adequate and sufficient height of attached gingiva facilitating good food deflection as well as adequate hygiene and brushing.
2.4.2. ADDITIVE MUCOSAL SURGERY Increase in soft tissue volume
2.4.2.1. Epithelial-connective tissue grafting, Increase the surface area of keratinized and attached gingiva around implants for functional purposes,
Technical
- Preparation of the recipient site
- Palatal (donor) harvest site
- Graft placement
- Making the crossed sutures
2.4.2.2. The connective tissue graft
- Purpose: To thicken the peri-implant gingiva for aesthetic purposes.
Buried connective tissue graft: Connective tissue contributions in the aesthetic sector can be carried out at several times during implant therapy; it is preferable to do them in the first stages of surgery.
- Indications
- Root and implant coverage (associated with a displaced flap),
- Tissue arrangement of the ridges, for example to thicken the mucous tissue,
- Gingival thickening of the periodontium or peri-implant tissues to obscure the vision of the titanium implant,
- Treatment of dyschromia (amalgam tattooing),
- Papillary reconstruction.
- Contraindications
- Insufficient donor tissue thickness: the connective tissue graft should be 1.5-2mm thick and the thickness of the palatal flap should be 1.5-2mm after graft harvesting to avoid necrosis.
- Therefore, at least 3mm of palatal soft tissue thickness is required at the donor site.
- Sampling technique Several techniques have been proposed, namely
Bruno’s technique
It consists of making a first incision in the palate perpendicular to the long axis of the tooth which goes up to the bone contact and is located approximately 02 to 03mm from the gingival edge. A 2nd incision begins between 01 to 02mm from the previous one in the apical direction almost parallel to the axis of the teeth up to a depth of 10mm and the graft is taken using a fine detacher.
TISSUE ARRANGEMENT Implantology course
- Preparation of the recipient site
The principle is to interpose a connective graft at the level of the area to be implanted where an epithelial flap has been previously prepared.
Incision : A horizontal incision is made with partial thickness dissection, without a vertical relieving incision so that a true pocket or envelope is formed at this area and into which the connective graft is slipped.
NB: The absence of a vertical discharge incision improves the vascular healing potential and the aesthetic result.
Sutures : This suture is made with an O-shaped stitch. Creation of sutures allowing the graft to slide
2.4.2. Pre-implant arrangement of hard tissue
Bone loss makes implant placement unfeasible from both a functional and aesthetic point of view. Surgical techniques for bone reconstruction for raising the alveolar ridge in cases of vertical, horizontal or mixed bone deficiencies, such as guided bone regeneration (GBR) and bone grafts.
Different materials have been proposed for this purpose to restore bone volume compatible with implant-supported reconstructive therapy.
2.4.2.1. Bone reconstruction materials
- Basic definitions
Autogenous graft: “Autologous bone is harvested and transferred from the DONOR site to sites of bone deficiency in the same person.”
Allogeneic graft: “Allograft is a tissue graft between individuals of the same specimen but of non-identical genetic composition.”
Xenograft: “Xenografts are derivatives of species other than humans.” They are considered biocompatible with human receptors and have osteoconductive properties.
Alloplast (synthetic) graft : “Alloplastic bone graft materials are synthetic materials, not of animal or human origin, developed to overcome the problems inherent in the use of autografts.”
- Required properties
Osteoinductive power: Induction of bone synthesis,
Osteoconductive power: Scaffolding role,
Osteogenic power : Possession or recruitment of osteogenic cells
Bioresorbability: Total or partial and its progressive replacement by bone,
Biocompatibility: Appropriate response in the host
Bioactivity and bioinertia: Ability to bind or not to the implant surface
Porosity:Invasion of biomaterial by blood vessels.
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Biomaterials must be partially or completely resorbable over time
this resorption ensured by the enzymatic activity of the cells, which will allow the progressive replacement of the material by newly formed tissue.
NB: A bone substitute is any material that will be completely resorbed and replaced. The term filler material will be used for the others.
- Autogenous graft
Harvesting of autogenous bone graft of intraoral origin
- Symphysis sampling
- Harvesting of the mandibular angle (also called “ram or retromolar graft”).
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Collection of autologous bone grafts of extra-oral origin
These types of grafts are indicated in cases of large maxilo-mandibular bone deficiency, from which they can be obtained from the parietal bone or the iliac crest, the latter constituting an extremely interesting donor site in terms of bone volume.
- ROG guided bone regeneration
Is a therapeutic option for the treatment of bone defects associated or not with the implant,
Its biological principle is based on the concept of cellular selection allowing new bone formation. Membranes used
- Principles of guided bone regeneration
The concept of guided bone regeneration follows the following principles (Buser et al.
1993, Fugazzotto et al.:
- Maintaining the space necessary for the recomposition of the bone volume to be recreated,
- Maintenance and protection of the blood clot, the very essential source of bone regeneration, which forms between and around the particles of the biomaterial so that angiogenesis and bone mineralization can take place,
- Establishment of a barrier against cellular invasion of the gingival connective and epithelial tissue, thus preventing cellular competition, which is unfavorable to bone mineralization,
- Gingival sutures obtained and maintained with good management of underlying postoperative forces.
- Indications for guided bone regeneration (Buser et al. 1993)
- Peri-implant dehiscences and fenestrations,
- Peri-implant intraosseous residual defects,
- Post-extraction implantation sites,
- Localized increase in the bony crest,
- Management of bone defects at future implantation sites preventing either the placement of an implant or its placement in an axis suitable in terms of function and aesthetics of the future prosthesis.
- Different types of membranes
For Friedmann et al in 2001 in guided bone regeneration , it would be important to cover the biomaterial with a membrane: Membranes in guided bone regeneration
Depending on the resorbability of the latter, some authors report that there would be no difference in terms of effectiveness between resorbable and non-resorbable membranes (Moses et al 2005).
We distinguish between bio-resorbable membranes and non-resorbable membranes. Generally speaking, these membranes allow:
- A one-step intervention.
- The predefinition and prefabrication of the shape and volume of the bone to be regenerated.
- They eliminate the risk of infection through their bio-resorption.
- Fibrin-rich plasma: PRF
The concept of PRF is to collect autologous growth factor concentrated into fibrin clot, this technique requires a centrifuge and a blood collection system.
Depending on the speed and centrifugation time, two forms of PRF are distinguished:
Advanced PRF (A-PRF): Obtained by centrifugation with a force of 200g for 08 minutes,
Injectable PRF (I-PRF):,Which is centrifuged at very low speed 60g-force and a short duration 03 minutes.
PRF membranes are able to simultaneously provide three key factors for tissue healing and maturation:
Angiogenesis: due to the presence of vascular endothelial growth factors VEGF and platelet-derived growth factor PDGF, and fibroblast growth factor FGF produced by white blood cells, as well as fibrin.
Immunity: due to the anti-infectious role of balan globules (the latter constitute 50% of the PRF)
Scaffolding for epithelial growth: role entirely linked to the membrane effect.
2.4.2.2. Pre-implant bone management techniques
2.4.2.2.1. Vertical Techniques
- Alveolar bone distraction : Principle of operation
Osteogenesis by progressive distraction responds to the stress mechanism in tension to which the bone is subjected, by a phenomenon of bone apposition, this bone has the capacity when it is subjected to stretching forces, to form a new bone tissue in the intercalary segment. It is a technique which allows the treatment of vertical bone deficiency
- Sinus lift
Sinus filling is generally required when it is impossible to place implants with a minimum length of 10 mm in the posterior region.
- MISCH classification
SA-1: height greater than or equal to 12mm with implant placement without augmentation.
SA-2 : height between 08 and 12 mm allowing the placement of an implant with prior elevation of the floor by the crestal route currently indicated even with values greater than or equal to 3 mm.
SA-3 : height between 05 and 08mm for which a lateral flap may be indicated. The implants can be placed at the same time as the sub-Sunisian filling, provided that their primary stability is ensured. A crestal osteotomy is also possible.
SA-4 : height between 0 and 03mm which requires an augmentation graft by lateral flap and a deferred placement of the implants.
TISSUE ARRANGEMENT Implantology course
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Mich’s classification
Two surgical procedures are commonly used to treat posterior maxillary bone deficiencies:
- The sinus filling technique using the lateral flap surgical approach.
- The technique known as the “Summers technique” using a crestal surgical approach.
- Triple-objective crestal sinus filling :
- Bone condensation to improve primary implant stability,
- Limited vertical increase of the alveolar ridge,
- Immediate placement of implants with the advantage of reducing the number of interventions. When indicated, this intervention is less invasive and faster than membrane elevation by lateral access.
2.4.2.2.2. Horizontal techniques
- Alveolar expansion
- Onlay grafting
Conclusion
An essential point to note is that this type of therapy is addressed to motivated and well-informed patients. There are no ideal grafting techniques or materials to choose from in clinical practice, but rather a growing number of materials and methods to use in individualized approaches to ridge reconstruction.
BIBLIOGRAPHY
- Seban A, Bonnaud P. Clinical practice of bone grafts and implants; 2012.
- Morchad B, Lauverjat Y. Crestal sinus lift: Piezosurgery and osteotomy. Implant 2012; 18: 91-98.
- Prouvost B, Dakic A, Frémont M, Bouchard P. Periodontology implant dentistry. Vol 2-surgical therapies. Paris: Edition Lavoisier Med ‘science; 2016.
- Choukroun J. PRF, 10 years later: Questions and certainties. Le FiL Dentaire 2010; 54: 26-28.
- Marc B. Pathological peri-implant gingiva. AOS 2014; 268:44-48.
- Rodriguez R, HartmannN, Weingart D. Current concepts of bone regeneration in implant dentistry. J surgery 2015; 10.4: 263-265. 22
- Tarragano H, Missika K, Moyal F, Lilouz B, Roches-Y. Oral surgery. France: Edition CdP; 2010.
- Costa Mendesa L, Sauvigne T, Guiol J. Morbidity of autogenous bone harvesting in implantology. Rev Stomatol Chir Maxillofac Chir Orale 2016;117:388-402.
- Harshakumar K, Varghese NM, Ravichandran R, Lylajam S. Alveolar ridge augmentation using autogenous block bone grafts harvested from mandibular ramus to facilitate implant placement: a case report. Int J Scientific Study 2014; 2.1:46-50.
- Antoun H, Karouni M, Sojod B. Guided bone regeneration: Results, limitations and perspectives. AOS 2013; 261: 11-21