What is supracrestal fiberotomy extent

The anterior implant restoration - like a natural tooth Part 1

The single tooth implant is part of the repertoire of treatment planning in the anterior area, especially when the substance is to be treated gently with intact neighboring teeth, non-abutments or only minimally worthy of restoration neighboring teeth. The high survival rates of dental implants with single tooth gaps in the upper jaw prove that osseointegration can almost be assumed. In contrast, the data on success rates related to aesthetic success is less clear.

  • Fig. 1: The five critical steps in replacing an anterior tooth with an implant-supported restoration.
In order to be able to objectively assess the aesthetic result of an implant restoration, which undoubtedly includes not only the white but also the red aesthetics, helpful indices have been suggested [5,13,20]. They all consider factors that were defined as standards for an aesthetic fixed implant restoration within the framework of the 3rd ITI consensus conference. In 2004, an aesthetic implant restoration was established there as one that harmonizes with the patient's perioral facial structures. The aesthetic peri-implant tissues must harmonize with the healthy surrounding dentition in terms of health, height, width, volume, color and contours. The prosthetic restoration should imitate the natural appearance of the missing tooth in terms of color, shape, surface quality, size and optical properties [24]. When teeth are lost, there are regular changes in hard and soft tissue. It is therefore our goal during treatment to compensate for the existing defect and thus to create harmony with the environment. As dentists, we have great influence on the maintenance and restoration of biological tissues. In order to convincingly restore structures such as papilla height, course and height of the soft tissue margin, convexity of the alveolar process and soft tissue color and surface texture, the goal of the largest possible tissue volume should always be kept in mind in addition to a preoperative risk analysis and constant evaluation of the individual work steps. In the following, five treatment phases are to be explained, with which - considered together - the aim is to enable the patient to have a single-tooth implant restoration that harmonizes with his perioral facial structures and is stable over the long term. The main 5 points are shown in Figure 1.

Diagnostic and pre-treatment phase

  • Fig. 2: Aesthetic risk analysis for edentulous alveolar ridge sections, slightly modified. Original in: ITI Treatment Guide, Volume 1, Implant Therapy in the Esthetic Zone - Single tooth replacement, Quintessenz Publishing Co, Ltd 2007.
A detailed preoperative planning with knowledge of all factors that significantly influence the end result facilitates patient education. The table “Esthetic risk assessment for edentulous sites” from the book ITI Treatment Guide [8] is ideally suited for this assessment of the risk factors and for predicting realistically achievable results (Fig. 2). Regardless of the patient's expectations, our goal should be the maximum achievable result. Under certain circumstances, however, a quick route is not feasible and several preparatory treatment steps are required before the goal is aesthetically realized. The patient's general state of health must be known in order to be able to assess the long-term prognosis of the implant therapy on the one hand and the short-term healing behavior on the other. For example, bisphosphonate treatment would require individual patient decisions regarding implant therapy. Knowledge of habits such as smoking, which can affect both short and long-term results, is of similar importance. Another aspect of the preoperative phase is periodontal diagnostics on all teeth with subsequent anti-infectious therapy if necessary. The survival and success rate of implants is slightly reduced in periodontal patients [22]. It is necessary to eliminate potential reservoirs for bacteria prior to implantation [15]. The scope of periodontal therapy depends on the initial findings and should aim at the maximum reduction of periodontal pathogenic germs. Any type of infection currently taking place or a previous infection in the surgical region also poses a risk for an aesthetic therapy result.

  • Fig. 3: Risk factor gingival infection, strongly curved gingival course. Fig. 4: Risk factor high smile line, apical infection. Fig. 5: Risk factor of interproximal attachment loss, uneven gingival course.
Regardless of the cause - be it periodontal, endodontic or traumatic - each of these infections is associated with a loss of soft and hard tissue as they heal and compromises tissue volume. Another risk factor is a high smile line on the part of the patient, which logically does not forgive any mistakes in the end result. It is therefore essential to take appropriate “smile” photos before planning an anterior restoration. The high smile line and a thin biotype are very difficult or partly unalterable factors. However, they have a decisive influence on the surgical procedure and the planning of the implant position. The shape of the crown and the bone level on adjacent teeth can pose a risk for open interproximal triangles and should be addressed preoperatively. Sufficient interradicular bone must be present in the mesiodistal dimension to ensure “soft tissue support” and thus long-term stability for the implant. If lateral incisors are not placed, for example, this may require further opening of the gaps. Every tissue defect, especially regarding the height, means a compromised aesthetic result. One has the greatest influence on the healing result before an extraction that is still necessary, in which both soft tissue and hard tissue defects can be anticipated and counteracted with substance-preserving measures with suitable measures. It should also be considered whether tooth extrusion techniques are capable of building up hard and soft tissue prior to extraction, according to the motto: hopeless teeth but not useless teeth (Fig. 3–5).

Gentle extraction

As early as 1967, Pietrokovski reported a significant resorption of the alveolar process after tooth extraction [23]. Van der Weijden [33] reports an average horizontal reduction of the alveolar ridge of 3.9 mm and an average vertical reduction of the alveolar ridge of up to 2 mm after anterior or premolar extractions. Schropp [27] describes an apical displacement of the buccal alveolar margin by 1.2 mm. The connection between the resorption of the buccal alveolar wall and the removal of the tooth could lie in the close connection during the development process of bundle bone, periodontal ligament and root cement and therefore cannot be influenced so much.

Many studies have shown that neither one of the many ridge preservation techniques nor the insertion of immediate implants is able to prevent the resorptive processes on the alveolar ridge, especially the buccal wall, after extraction [3, 4, 7, 10, 16]. What remains, however, is the possibility of preventing additional trauma by protecting the structures during the extraction process. This applies to the buccal bone wall, the periosteum and the adjacent gingival structures. The use of periotomes - alternating with slightly rotating pulling movements using pliers - helps here. Special ultrasonic cutting devices offer new substance-friendly options. To prevent additional resorption, pressure peaks during luxation and the formation of a mucoperiosteal flap should be avoided. Following an extraction, for example, in the sense of guided tissue healing, mechanical protection of the blood clot and support of the proximal and buccal soft tissue can be achieved by integrating a temporary with ovate pontic design [29]. However, if you start with a tissue minus before the extraction, simultaneous augmentation - be it in the sense of a ridge preservation technique, guided bone regeneration or a soft tissue build-up - can be useful at the time of extraction. The main aim is to preserve the vertical dimension after extraction, as this is very difficult to reconstruct (Fig. 6 and 7).

  • Fig. 6: Adhesive anchoring of the tooth crown with ovate pontic design for mechanical protection of the blood clot and as a soft tissue support.
  • Fig. 7: Filling of the alveolus with xenogenic, mineralized bone substitute material and insertion of a membrane.

Precise implant position

Stable volume ratios are the prerequisite for a long-term biological aesthetic appearance of an implant-supported anterior crown. Ono [21] describes an undulating course of the mucosa, an adequate crown length adapted to neighboring teeth, convex shaped, sufficiently thick buccal mucosa and a papilla that harmonizes with the natural dentition as factors for aesthetic soft tissue contours. In this context, especially with regard to the papilla height and the stability of the buccal mucosa, the concept of the biological width on the implant should be mentioned. Due to the flat implant shoulder and the associated, partly subcrestal localization, it differs from the concept of biological width on the tooth, which is supracrestal [34]. Thus, the bony foundation for the proximal soft tissue for the formation of a papilla in the implant is not guaranteed. Spear [29] and Kois [18] concluded that in addition to the proximal bone level, the presence of an adjacent dental soft tissue attachment and sufficient volume for the interproximal gingival soft tissue are also important. For the implant position, this means that all three dimensions, namely the mesio-distal, the bucco-lingual and the apico-coronal, must be included in the planning.

In the mesio-distal direction, an implant diameter should be selected that allows approx. 1.5 mm space for interradicular bone. Adell [2] demands this with consideration of the periodontal ligament of the neighboring tooth for undisturbed osseointegration. Tarnow [32] reports about 1.3–1.4 mm bone loss in the lateral direction after exposure of an implant. In order to avoid resorption of the bone on the neighboring tooth, a minimum distance of 1.5 mm should be maintained.

The buccal-lingual position of an implant should be chosen so that even after remodeling of the bone (as mentioned above, a lateral component of 1.3–1.4 mm must be anticipated) the buccal bone wall remains intact in the vertical direction and thus remains intact does not form the basis for recessions. If an average of 0.7 mm resorption due to the surgical trauma is added [30], this assumes a buccal bone thickness of approx. 2 mm [14] and in most cases requires augmentative procedures. The thickness of the mucosa influences the supracrestal height of the peri-implant soft tissue [6]. Augmentation with connective tissue or homologous substitute materials offers additional protection in order to locally positively influence the underlying biotype.

  • Fig. 8: Precise implant position buccolingual ... Fig. 9:… vertical and… Fig. 10:… mesio-distal.
Finally, the vertical position of the implant shoulder should be based on the new, prosthetically defined enamel-cement boundary - i.e. the exit point of the crown from the gingiva - and be approx. 3 mm apical from this. When placing the implant, any type of template that can reproducibly display the exact position intraoperatively is helpful. Since a further apical displacement of the facial mucosal margin is to be expected in the course of a year after the implant crown has been inserted [9,14,28], our implant placement always provides for a connective tissue augmentation in the anterior area in order to start the prosthetic phase with a slight increase in tissue (Fig. 8-10).

The implant crown - many functions

The functional, aesthetic and biological properties of the implant crown should imitate the lost natural tooth as well as possible. From a periodontological point of view, the submucosal portion of the implant abutment and the implant crown has the greatest influence on the apico-coronal position and the facial course of the free marginal mucosal border. Here, too, a sufficient supply of soft tissue is a prerequisite. The key to a predictable and stable red result in the anterior zone is the screw-retained temporary in combination with a slight excess of tissue. If a natural emergence profile from the implant shoulder to the marginal tissue margin has been achieved through sequential adaptation of the temporary, this can be obtained by precisely converting the submucosal functional area into the definitive abutment-crown combination. Small and Tarnow assume that a three-month waiting period after the end of the shaping process gives sufficient time for tissue stabilization and that no further apical displacement of the free mucosal margin is to be expected [28].

  • Fig. 11: Submucosal shaping and design using a functional, screw-retained, provisional crown. Implementation of the emergence profile achieved in an individual abutment with a 1 mm submucosal preparation margin.
Several concepts for shaping the emergence profile have been published, the shapes of which range from convex to concave, depending on whether one wants to provoke an apical displacement or a coronal displacement of the marginal mucosa [25,31]. It should be noted, however, that too frequent interruption of the fragile attachment of the peri-implant mucosa to the temporary can lead to bone remodeling [1]. For this reason, attempts should be made to minimize the number of intraoral modifications to the temporary by specifying the marginal mucosal border in all three dimensions on the model with gingival mask as precisely as possible. After the emergence profile has been fully formed and a natural marginal mucosal course has been achieved, the three-dimensional soft tissue situation must be precisely transferred to the master model using an individualized impression post. The technician's precise knowledge of the course of the mucosa makes it possible to manufacture an individualized abutment with an ideal crown edge course. A circular crown margin that is only minimally submucosal minimizes the risk of excess cement and thus the risk of developing peri-implantitis (Fig. 11).

Record reference data and define the implant recall

  • Fig. 12 and 13: Probing 2 weeks after incorporation of the definitive restoration.
The documentation of a peri-implant initial finding, the so-called baseline, after the implant-supported denture has been incorporated is of great importance in the long-term care of the patient. The stability or the development of a peri-implant disease can be determined by comparing probing depths, figs. Presence of bleeding on probes (BOP) and x-rays are relatively reliable. In the literature, the prevalence of perimucositis and peri-implantitis varies due to the different underlying disease criteria and is high at 80% for mucositis and 28% or> 56% of the subjects for peri-implantitis [26,12]. Lang and Berglundh [19] assume that mucositis is the preliminary stage of peri-implantitis. This means that we have to detect inflammation of the peri-implant tissue at an early stage. If peri-implantitis is diagnosed on the basis of the relevant findings, therapy should be initiated quickly because of the sometimes very rapidly progressing lesions [15]. Thus it becomes clear how important the assessment of the patient's individual risk factors is for the development of peri-implantitis. The main factors to be mentioned are inadequate oral hygiene, smoking and the medical history of the previous disease periodontitis - as signs of a certain susceptibility to infection [15]. Taking into account the risk indicators mentioned, the patients are included in an individual implant recall. During the recall session, findings such as plaque index, BOP and probing depth are recorded and, if necessary or every 4 years, X-rays are taken. This procedure offers both the practitioner and the patient the security of long-term implant success (Fig. 12 and 13).

Summary and conclusion

The treatment of a single tooth gap with an implant in the aesthetically relevant area is a challenge for the practitioner. It requires a high level of know-how and meticulous planning and implementation. Often, a quick path cannot be implemented and several preparatory treatment steps are required before the treatment goal is aesthetically achieved. Ergo, this is a time-consuming and costly treatment with very different levels of risk depending on the case. Observing the five treatment phases shown here will help to realistically assess the risk, to carry out the treatment gently and correctly and to keep the result permanent.In this way, we are able to provide the patient with a long-term stable single-tooth implant restoration that harmonizes with their perioral facial structures.