Articles - Forum Implantologicum

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Feature Article

May 28, 2019 // 26 min read

Early Implant Placement Following Single Tooth Extraction in the Esthetic Zone with Contour Augmentation – Selection Criteria, Surgical Procedures and Long-Term Results

DOI: 10.3290/iti.fi.45655

Abstract

Implant placement post single tooth extraction in the esthetic zone is an important and frequent indication for implant therapy. Today, the clinician can choose from four different treatment approaches for the timing of implant placement. The decision for the most appropriate treatment plan should be based on a thorough clinical and radiographic examination and well-defined selection criteria. Early implant placement after soft tissue healing is one of the treatment options available. This approach is applied by our team in the case of a thin bone wall phenotype (<1 mm) or a missing facial bone wall at the extraction site, and sufficient bone volume available in the palato-apical area to allow good primary stability of the implant. The surgical procedures include a flapless tooth extraction, a 4-to-8 week soft tissue healing period, implant placement in the correct 3-dimensional position, a simultaneous contour augmentation on the facial aspect with the GBR technique using a 2-layer composite graft with locally harvested autologous bone chips and a low-substitution bone filler, application of a double-layer collagen membrane, and a tension-free primary wound closure. Following 8 weeks of healing, the implant site is reopened with a punch technique, and the implant can be restored with a screw-retained single crown. The rationale for this surgical procedure is presented including inclusion criteria, surgical procedures, case reports and long-term documentation.

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Introduction

Implant placement post extraction of a single tooth in the esthetic zone is a frequent and clinically demanding indication of implant therapy (Engel Brugger et al. 2015). Today, the clinician can choose from different treatment options: immediate, early or late implant placement (Buser et al. 2017, Fig. 1). The correct timing of implant placement post extraction is an important decision for the achievement of an optimal esthetic treatment outcome with high predictability. Thus, the topic of post-extraction implant placement has been addressed at four consecutive ITI Consensus Conferences since 2003 in form of narrative or systematic reviews (Chen et al. 2004, Hammerle et al. 2004, Chen & Buser 2009, Chen et al. 2009a, Chen & Buser 2014, Morton et al. 2014, Gallucci et al. 2018). In addition, it was also the main topic of the ITI Treatment Guide Volume 3 (Chen & Buser 2008). These consensus conferences and the corresponding review papers defined first the timing and treatment options, introducing a Type I - IV classification and descriptive terms; then the identification of risk factors for the development of complications, and finally the definition of selection criteria for the most appropriate treatment approach in a given clinical situation.

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Fig. 1: The various treatment options in post extraction implant placement and the relevant literature from ITI Consensus Conferences and related activities

In the esthetic zone, all four treatment options are utilized in daily practice by our team, but with differing frequency. Immediate implant placement (type I) is only used in ideal clinical situations (Buser et al. 2017). The most important factor is an intact and thick facial bone wall of at least 1 mm in thickness (Table 1). This approach is performed flaplessly in combination with static computer-assisted implant surgery (sCAIS) to optimize an ideal 3-dimensional (3D) implant position. This approach is highly attractive for patients, since it offers both low morbidity and an immediate restoration with a fixed provisional. However, from a surgical point of view, this method is demanding and considered a complex procedure, according to the SAC Classification (Dawson & Chen 2009). Thus, it should only be carried out by master clinicians with a sufficient number of patients per year to establish the necessary routine for this demanding surgical technique. It is limited in application due to the infrequent presence of a thick bone wall phenotype in the anterior maxilla (Braut et al. 2011). The immediate approach is presented in a separate paper by Stephen Chen in this issue of Forum Implantologicum. Late implant placement (type IV) in a healed site with at least 6 months of healing post extraction, on the other hand, is rarely used by our team in the esthetic zone, since it is the least attractive approach, implementing a long treatment period of 8 months or longer between tooth extraction and implant restoration for the patient. When this approach is indicated, socket grafting with a low-substitution bone filler is routinely used to reduce the amount of local bone resorption (Table 1). More details of this approach are presented in the paper by Stephan Fickl.

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Table 1: The selection criteria and surgical aspects of immediate, early and late implant placement following single tooth extraction in the esthetic zone

In between these two treatment modalities is an additional approach called early implant placement. Early implant placement after soft tissue healing (4 to 8 weeks; type II) or partial bone healing (12 to 16 weeks; type III) is often used by our team to reduce the risk associated with immediate implant placement, and to avoid an unnecessarily long treatment period typical for late implant placement. This specific approach was first described in detail more than 10 years ago (Buser et al. 2008). In esthetic sites, early implant placement after soft tissue healing of 4 to 8 weeks (type II) is preferred whenever possible, whereas early implant placement following 4 months of partial bone healing (type III) is our favorite approach in first molar sites post extraction in the mandible.

The goal of this clinical review paper is to present the concept of early implant placement in esthetic single tooth sites including the biologic rationale and selection criteria for this approach, the step-by-step surgical procedures, and the long-term results obtained at the University of Bern in the past 20 years.

Fig. 1: The various treatment options in post extraction implant placement and the relevant literature from ITI Consensus Conferences and related activities

Table 1: The selection criteria and surgical aspects of immediate, early and late implant placement following single tooth extraction in the esthetic zone

Fig. 2a: Four different patients referred to our clinic for extraction and implant placement. These cases document the variety of different clinical and radiographic findings in daily practice:
A thick and intact facial bone wall

Fig. 2b: A thin and not fully intact facial bone wall

Fig. 2c: A deficient facial bone wall and a very thin palatal bone wall

Fig. 2d: An extended periapical bone lesion

Fig. 3a: Early implant placement in a 74-year old female patient with gingival recessions at teeth 12, 14 and 15:
The patient was referred due to repeated loss of retention of crown 13. The extraction 13 and an early implant placement 13 are planned

Fig. 3b: The orofacial CBCT shows no evidence of a facial bone wall

Fig. 3c: The coronal view shows a sufficient crest width of more than 6 mm mesially and distally to tooth 13

Fig. 3e: The root was separated oro-facially to remove the root in two smaller pieces

Fig. 3f: Following extraction, the socket was debrided and filled with a collagen plug to stabilize the blood clot. A small tear of the buccal gingiva was sutured with an interrupted suture

Fig. 3g: A prepared provisional and removable partial denture was applied

Fig. 3h: Soft tissue healing after 8 weeks has progressed well, additional keratinized mucosa has formed, and inside the tissue, bundle bone resorption has taken place

Fig. 3i: 8 weeks following extraction, the implant surgery is performed. In the crestal area, a slightly palatal incision is routinely utilized to mobilize the soft tissues formed inside the socket as part of a thick buccal flap

Fig. 3j: A triangular mucoperiosteal flap is elevated. The intra-surgical inspection shows the typical crater-like defect on the buccal aspect, and exceptional thickness of the flap in the area of the socket

Fig. 4a: Harvesting of autologous bone chips and bone conditioned medium (BCM):
Following flap elevation, the cortical bone surface towards the canine fossa is used to harvest the bone chips

Fig. 4b: A sharp bone scraper is used to harvest the 1 – 2-mm large, curled bone chips

Fig. 4c: The harvested chips are instantly stored in a mixture of the patient’s own bone and Ringer solution (50:50)

Fig. 4d: 15 to 20 minutes later, the blood-Ringer solution contains growth factors released from the hone chips

Fig. 4e: The BCM solution is used to soak the DBBM particles

Fig. 4f: The DBBM granules are activated with the BCM by absorbing the growth factors present in the BCM solution

Fig. 3k: The bone level implant (ø 4.1 mm) is inserted in a correct 3D implant position

Fig. 3l: Corono-apically, the implant shoulder is positioned roughly 3 mm apically to the mid-facial implant crown margin

Fig. 3m: Oro-facially, the implant shoulder is positioned about 1 to 1.5 mm palatal to the point of emergence of the future implant crown

Fig. 3n: A correct implant axis is important to allow for a screw-retained crown later on

Fig. 3o: Prior to bone augmentation, a 2-mm healing cap is inserted. Please note that the implant shoulder is positioned sub-crestally. On the facial aspect, a 2-wall defect is present caused by bundle bone resorption following extraction

Fig. 3p: First, a layer of autologous bone chips is applied, which were harvested locally straight after flap elevation

Fig. 3q: The second layer of DBBM granules is then applied for local contour augmentation

Fig. 3r: The augmentation material is then covered by a collagen membrane to have a temporary barrier membrane for the next 4 to 8 weeks of healing. The membrane is applied with a double layer technique

Fig. 3s: Following incision of the periosteum, the surgery is completed with a tension-free primary closure

Fig. 3t: 8 weeks later, the healed mucosa was reopened with a punch technique to exchange the 2-mm healing cap by a longer 4.5-mm healing cap

Fig. 3u (a): Clinical status 6 months following implant placement. The implant crown was fabricated by the referring dentist. The mucosal margin is convex, correctly positioned and shows no visible signs of inflammation

Fig. 3u (b): The corresponding periapical radiograph shows stable bone crest levels

Fig. 3v (a): The 3-year follow-up examination shows stable peri-implant soft tissues. The patient has an excellent home care resulting in a healthy peri-implant mucosa free of inflammation

Fig. 3v (b): The corresponding periapical radiograph confirms the stability of the crestal bone

Fig 3v (c): The oro-facial cut of the CBCT shows a very thick facial bone wall

Fig. 5a: 10-year documentation of a patient treated with early implant placement and simultaneous contour augmentation in 2006:
Clinical status 8 weeks following tooth extraction

Fig. 5b: Intra-surgical view shows the crater-like bone defect on the buccal aspect with a 2-wall defect morphology

Fig. 5c: 10-year follow-up results with the smile line displaying an excellent esthetic outcome

Fig. 5d: The patient’s good home care is a contributing factor to a pleasing esthetic outcome. The facial mucosa is convex, the vertical position of the mucosal margin is excellent

Fig. 5e: The peri-apical radiograph shows excellent stability of the crestal bone around the platform-switched bone level implant

Fig. 5f: The CBCT shows a fully intact and thick facial bone wall after 10 years of function. The peak of the facial wall is roughly 1.5 mm coronally to the implant shoulder

Fig. 6a: 20-year follow-up of the very first patient treated with early implant placement and simultaneous contour augmentation in January 1998:
Clinical status of the patient, 6 weeks following extraction of the first premolar by the referring dentist. Note the gingival recession at the canine

Fig. 6b: Intra-surgical view demonstrating the extended crater-like bone defect on the buccal aspect with a 2-wall defect morphology. This defect was augmented with the surgical technique described

Fig. 6c: 20-years later, the clinical status shows stable peri-implant soft tissues with a convex buccal mucosa and a pleasing esthetic outcome

Fig. 6d: The peri-apical radiograph shows excellent stability of the crestal bone around the tissue level implant with a machined implant surface in the neck region

Fig. 6e: The horizontal cut of the CBCT shows the thick facial bone wall after 20 years of function

Fig. 6f: The oro-facial cut confirms a fully intact buccal bone wall of roughly 2 mm thickness