Dental Implants: Immediate Placement and Loading in the Esthetic Zone

Abstract

Extraction of an anterior tooth is always a traumatic event for patients, regardless of their age. In the past, patients were required to wait long months for bone healing and for implant integration, using an uncomfortable removable denture. In the last decade or so, dentists came to the understanding that when done correctly and in the right cases, immediate placement and loading techniques can result in aesthetically pleasing temporary and long-term results, while maintaining supporting bone and soft tissues. In fact, it was found, that placing an immediate implant rather than waiting can in fact prevent some of the bone resorption which happens after extractions.

1. Introduction

Anterior teeth function in eating and speaking, of course, but also have a role in shaping facial aesthetics. In fact, many people see them as part of their personal identity. For these reasons, loss of an anterior tooth is always a traumatic event for patients, regardless of their age. To relieve their physical and emotional pain, patients seek a fixed restorative solution as fast as possible.

Patients who suffered severe trauma and lost multiple teeth are usually aware of the fact that it is almost impossible to restore their teeth to their original look. With a good explanation from a dentist, their expectation level can be adjusted so that it is realistic and so that they can accept a non-ideal restoration, which is both aesthetic and functional but not identical to the way their original teeth and gums looked before the trauma.

Patient expectation level is completely different when only one anterior tooth is lost. In these cases, it is clear to patients, regardless of their condition, that it is possible to restore both the “white” and the “pink” to their original state so that both the restoration and the gum-line look exactly like the homologous existing tooth.

The problem is that when a tooth is lost, two known phenomena happen: flattening and loss of proximal papillae as well as horizontal and vertical bone loss.

Although there are techniques to restore lost soft and hard tissues, these techniques are complex, require extremely high skills and experience, require long healing periods and are expensive. And on top of this, even in the best hands, these techniques are not 100% predictable [1, 2, 3].

Two advancements opened the way to preserve both bone and soft tissue architecture in the anterior upper segment. One is the understanding that placing an implant immediately after extraction can reduce bone loss at the site, maintaining the buccal aspect above the restored tooth as close as possible to the way it looked prior to the trauma [4, 5, 6]. Another way to preserve buccal bone and gingival architecture is the “Socket-Sheild” technique. In this technique, the root is cut mesiodistally leaving its buccal aspect attached to the buccal bone, and the implant is placed behind it. Although found effective [7, 8, 9], this technique is extremely difficult to perform and requires conditions that do not always exist, therefore, it will not be discussed in this chapter.

Prior to treatment, and as in any medical and dental procedure, it is critical to start with a correct diagnosis. The entire site and its surroundings with a focus on the remaining root, the integrity of the buccal bone, the architecture of the gums around the site and any evidence of infection at the gum level or around the root must be evaluated. Taking photographs of the anterior region before treatment is highly recommended, both for further analysis and evaluation of the healing phase and medico-legal reasons.

The second most important phase is to carefully evaluate all possible treatment options and discuss them with the patient, who should be notified about the pros and cons of each option, including restoring the missing dentition with a fixed bridge, a removable device, or an implant. If an implant-based solution is chosen, the different treatment sequences: immediate placement, immediate placement and loading or late placement with or without immediate loading must also be discussed with the patient, presenting again the pros and cons of each option. And lastly, the patient expectations must be discussed, ensuring that he/she understands that no one can achieve 100% success rates in any medical or dental procedure.

Short and long-term success requires mastering both the “white stuff” (the crown) and the “pink stuff” (the gingiva surrounding the site). The control over the “white stuff” is almost always in the hands of a master dental technician. And indeed, dental technicians who are also artists can achieve amazingly wonderful aesthetic results when it comes to mimicking the natural shade, translucency, transparency and anatomical characteristics of the adjacent teeth. It is not always easy, but undoubtedly possible. In contrast, the control over the 3D position of the implant and the recreation of correct emergence profile and gingival architecture is completely in the hands of the operating dentist or the dental team. The correct positioning of the implant at the site, its angulation, depth and especially the position of its opening is critical to enable achievement of the desired aesthetic and functional result. Next, a temporary crown with a unique gingival design, which ensures proper support for the gums and papillae, must be placed [10, 11, 12, 13, 14, 15]. Following a period of healing and gingival maturation, it is mandatory to transfer the exact achieved gingival architecture to the dental laboratory so that the final crown is made with the desired gingival shape to ensure long-term stability of the gumline.

This chapter aims to present the different stages of immediate placement and loading in the anterior aesthetic zone, focusing on critical influencing parameters that affect short- and long-term success.

2. Stages of immediate implant placement and loading in the aesthetic zone

The long-term aesthetic success of a restoration in the anterior zone and its gingival architecture requires a thorough analysis of the condition of the injured area. Patients need to be informed and must understand their condition so that they develop realistic expectations related to the possible final outcome.

2.1 Evaluation of the site

Bone condition and height around the socket, especially in the buccal aspect and near adjacent teeth, are critical. Loss of bone in any direction, especially in the buccal area, severely affects the ability to simply restore site’s aesthetics. Loss of bone due to infection, periodontal disease, root fracture or crack or iatrogenic accidental damage to the delicate buccal bone during extraction may contra-indicate immediate placement and loading of implants in such sites. In these cases, a staged approach, including bone and/or gingival augmentation, may be required prior to implant placement. The type of gingiva is also important since it is easier to control thick biotype gingiva than thin biotype gingiva, although, with careful management, it is possible to achieve good results in any gingival type.

2.2 Implant design and drilling protocol alterations

Immediate implant placement and loading is an accepted and predictable dental procedure, with high success rates. As in other implant placement procedures, high initial stability is one of the most important factors related to their short- and long-success rates.

There is a critical difference between the way immediate implants and standard implants gain their primary stability. While standard implants gain stability throughout their length, immediate implants gain stability through the threads of their apical section. This is a result of the fact that the diameter of the extraction socket is almost always wider than the diameter of the implant (Figure 1). Because of this, it is highly recommended that the dentist chooses an implant with deep and sharp apical threads, (Figure 2), that can cut through bone to ensure high initial stability. In addition, the dentist MUST alter the standard drilling protocol, taking into account the diameter of the apical core of the implant used, so that the osteotomy is not wider than this core. In other words, high initial stability is gained through these apical threads, and mild compression of bone at the apical section of the placed implant, utilizing the accepted concept of “Under Drilling” techniques [16, 17]. Since each implant system has different diameters at the apical section and different drill diameters, the dentist must study these parameters of the system used, to ensure that the osteotomy is small enough to ensure high implant stability while being large enough to allow the core of the implant to penetrate in.

Figure 1.

Areas of support for an anterior implant.

Figure 2.

An implant with wide apical screw design.

Correct planning considering these parameters will ensure high initial stability (above 35NCM) to support immediate placement of a temporary restoration that enables aesthetics without being exposed to functional occlusal loads.

2.3 Drilling depth and implant position

The specific 3D position of the implant’s head is critical for an ideal restoration [18, 19, 20]. A depth of 3–4 mm is usually sufficient to allow the creation of a correct emergence profile, without creating a deep gingival pocket that is too hard to maintain. It should be clear that screw-retained restorations are by far better than cement-retained restorations as temporary restorations on immediate implants. One reason is that there is no cement involved in screw-retained restorations, so no cement may accidentally be pushed into the fresh socket. The second reason is the ease of manipulation of screw-retained restorations and the fact that no vertical force needs to be placed on the newly placed implant while preparing and while trying-in the temporary crown. This means, while placing the implant, effort must be put to place the opening of the implant at the cingular area of the restored tooth and at an angle that would enable easy access to the retaining screw from the palatal side of the crown (Figure 3).

Figure 3.

Screw hole at the cingulum area.

Regarding implant’s depth, many dentists are not aware of the difference between platform-stitching implants and standard internal hex ones when it comes to the position of the restorative platform. While in standard internal hex implants, the crown may emerge from the implant’s platform or very close to it, in platform-stitching implants, there is a 1–2 mm gap between the implant’s platform and the base of the restoration (Figure 4). This means that when using platform-switching implants, the head of the implant must be placed deeper than when using standard internal hex ones.

Figure 4.

Platform switching implant type.

2.4 Creating a temporary crown with an emergence profile that supports the gingiva

The alveolar bone is critical to support the gingiva. Lack of bone at the buccal aspect of the socket, at the proximal aspect/s or even at the palatal aspect may lead to gum recession and the creation of “black holes” and flattening of the gingival architecture [20, 21]. Therefore, it is critical to ensure that the socket is intact after extraction, and that bone surrounds it all around. When this is the situation, it is beneficial to support the gum tissue immediately after extraction with a correctly made temporary crown, which will maintain the shape of the gums and papillae. The best and easiest way to do it is by using a screw-retained temporary crown, made with an “ovate pontic” emergence profile design at its base facing the implant (Figure 5) [22, 23, 24, 25]. A standard and round-shaped healing abutment is not ideal since it creates a round opening in the gingiva that does not have the required gingival architecture (Figure 6). This means that when standard healing abutments are used, an additional surgical procedure may be required to achieve the desired gingival contour.

Figure 5.

Ovate pontic design.

Figure 6.

Tissue around a standard healing cap.

The design of a correct emergence profile requires an analysis of the 3D position of the head of the implant, its depth, and the level of support needed by the gingival tissues. 3–4 mm of depth is sufficient to create correct ovate-pontic shape that will support the gums (Figure 7). The gingival aspect of the temporary crown must be polished to prevent gum irritation and plaque accumulation, and the patient must be taught how to clean it. Since gingival tissues tend to shrink and change during the healing phase, some mild adjustments of the emergence profile may be required once osseointegrate is completed, to ensure aesthetically pleasing outcome.

Figure 7.

Ovate pontic emergance profile.

Once the temporary crown is completed, it should be firmly attached to the implant, and the access hole must be sealed. Occlusal adjustment must ensure that minimal (if any) occlusal loads are placed on the crown during the healing phase. It is also recommended that proximal contacts are minimal and sufficient to prevent food impaction between the temporary crown and the adjacent teeth. It is mandatory to explain to patients that the temporary crown is made for supporting the gums and for aesthetic reasons only and that biting, chewing or any other application of forces (such as during smoking, parafunction, nail-biting etc.) may cause implant failure.

The temporary crown must not be removed during the healing and osteointegration period and sufficient time must be given to allow gingival maturation. When done correctly, the gingival architecture is preserved, as seen when removing the temporary crowns (Figure 8a and b).

Figure 8.

a. Tissue of 28 year old patient after crown removal. b. Tissue of 80 year old patient after crown removal.

2.5 Transferring gingival data to the dental laboratory

To ensure that the lab technician fabricates a crown that is identical to the temporary one, the internal shape of the healed gingival architecture must be transferred to the laboratory. There are several published methods to do that. Both silicone-based impressions and intra-oral scanning are acceptable [26, 27]. In addition, it is recommended to transfer a physical impression of the emergence profile and the shape of the temporary crown (Figure 9), as well as photographs from a few angles. This allows the technician to better visualize the required shape and its actual environment.

Figure 9.

A technique to transfer crown shape to the dental lab.

2.6 Long-term maintenance

Like any tooth, the tissues around an implant are dynamic and constantly change and are impacted by the accumulation of plaque, calculus and food particles and time, of course. Daily cleaning must include soft brushing, the use of floss, or a super-floss underneath the ovate-pontic shaped crown. In addition, patients need to understand the need to have periodic check-up visits and treatment by a hygienist to ensure short- and long-term success of any tooth and restoration.

3. Conclusion

The restoration of a single anterior tooth is one of the most demanding procedures in dentistry. Each aspect of the treatment influences the end result: from a correct diagnosis to case selection, from the choice of a specific implant design to alteration of the drilling protocol, and from the clinical decision of where to three-dimensionally place the head of the implant to the shape of the gingival aspect of the temporary and final crown. Thorough understanding and correct implementation of these principles, coupled with the help of an artist dental technician can lead to long-term solutions for the benefit of our patients (Figure 10).

Figure 10.

Ten years follow up of an immediate loaded implant with final crown.

Acknowledgments

Crown 21, shown in Fig 10 was fabricated by Mr. Tamir Heker from Tamir Heker Dent. Tel-Aviv, Israel.