Lazzara RJ Immediate implant placement into extraction sites: surgical and restorative advantages. Int J Periodontics Restorative Dent. 1989; 9:332-343
Atieh MA, Payne AG, Duncan WJ Immediate placement or immediate restoration/loading of single implants for molar tooth replacement: a systematic review and meta-analysis. Int J Oral Maxillofac Implants. 2010; 25:401-415
Ketabi M, Deporter D, Atenafu EG A systematic review of outcomes following immediate molar implant placement based on recently published studies. Clin Implant Dent Relat Res. 2016; 18:1084-1094 https://doi.org/10.1111/cid.12390
Ragucci GM, Elnayef B, Criado-Cámara E Immediate implant placement in molar extraction sockets: a systematic review and meta-analysis. Int J Implant Dent. 2020; 6 https://doi.org/10.1186/s40729-020-00235-5
Cosyn J, De Bruyn H, Cleymaet R Soft tissue preservation and pink aesthetics around single immediate implant restorations: a 1-year prospective study. Clin Implant Dent Relat Res. 2013; 15:847-857 https://doi.org/10.1111/j.1708-8208.2012.00448.x
Smith RB, Tarnow DP Classification of molar extraction sites for immediate dental implant placement: technical note. Int J Oral Maxillofac Implants. 2013; 28:911-916 https://doi.org/10.11607/jomi.2627
Borie E, Oliví DG, Orsi IA Platelet-rich fibrin application in dentistry: a literature review. Int J Clin Exp Med. 2015; 8:7922-7929
Chu SJ, Salama MA, Salama H The dual-zone therapeutic concept of managing immediate implant placement and provisional restoration in anterior extraction sockets. Compend Contin Educ Dent. 2012; 33:524-534
Linkevicius T, Valantiejiene V, Alkimavicius J The Effect of a polishing protocol on the surface roughness of zirconium oxide. Int J Prosthodont. 2020; 33:217-223 https://doi.org/10.11607/ijp.6686
Valantijiene V, Mazeikiene A, Alkimavicius J Clinical and immunological evaluation of peri-implant tissues around ultra-polished and conventionally-polished zirconia abutments. A 1-year follow-up randomized clinical trial. J Prosthodont. 2023; 32:392-400 https://doi.org/10.1111/jopr.13670
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Smith RB, Tarnow DP, Sarnachiaro G Immediate placement of dental implants in molar extraction sockets: an 11-year retrospective analysis. Compend Contin Educ Dent. 2019; 40:166-170
Javed F, Romanos GE The role of primary stability for successful immediate loading of dental implants. A literature review. J Dent. 2010; 38:612-620 https://doi.org/10.1016/j.jdent.2010.05.013
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Dental implants placed immediately into single-rooted extraction sockets have been well documented over the years. More recently there has been an increase in the publications looking at immediate implants in molar extraction sites. The advantages of reducing treatment times and limiting the number of surgeries helps with patient acceptance and is also advantageous for the surgeon. There are also clinical advantages of improved pink aesthetic scores and reduced food packing for the definitive restorations. This case report demonstrates the techniques used in achieving a predictable outcome in immediate molar implant treatment.
CPD/Clinical Relevance:
The advantages and the methods used for placing an implant into a molar extraction socket and restoring it are discussed.
Article
Implants placed immediately into molar extraction sites were first documented in the literature over 30 years ago1 and more recent systematic reviews have shown their success rates to be comparable to that of delayed implant placements.2,3,4 While the benefits of immediate implants in the anterior zone may be obvious, where aesthetically critical sites benefit from quicker treatments and improved pink aesthetic score (PES) by maintaining the soft tissue profiles;5 prevention of soft tissue collapse in molar sites can also be beneficial in preventing food packing, which is a common problem around molar implant crowns.
Immediate molar sites have been classified into three different types6 depending on how much septal bone remains between the roots. If the implant can be fully encased into the septal bone, this is a type A socket. If, however, part of the implant is exposed, but is primarily supported by the septal bone, this is a type B socket. Where there is no septal bone, and a wide diameter implant must be used to engage the buccal and palatal bone, then this is a type C socket. Traditional engagement, with the implant 3–5 mm apical to the socket to achieve primary stability, is not often possible in molar sites owing to the presence of anatomical structures (namely the inferior dental canal and the maxillary sinus).
The article shows the step-by-step protocol for achieving a predictable result when undertaking such a treatment in a type B socket.
Case report
A 65-year-old female patient presented with a vertical fracture through the lower right first molar tooth, extending subgingivally (Figure 1), which was deemed unrestorable. The pre-operative radiograph (Figure 2) and CBCT scan (Figure 3) show apical radiolucency consistent with the diagnosis of apical periodontitis, secondary to root fracture. Following a discussion with the patient, she decided that an implant placed on the day of extraction would be the best way forward.
Figure 1. Pre-operative view of the lower right first molar tooth showing the mesial to distal vertical fracture.Figure 2. Pre-operative radiograph showing the lower right first molar with apical radiolucency.Figure 3. Sectional view from CBCT scan through (a) the distal and (b) the mesial root.
The tooth was subsequently sectioned to separate the mesial and distal roots (Figure 4), to allow for atraumatic extraction. Periotomes and fine luxators were used to gently elevate the roots from the socket, preserving the socket bony walls, including the septal bone (Figure 5). The socket was degranulated using degranulation burs and a Mitchel's trimmer (Figure 6).
Figure 4. Tooth was sectioned bucco-lingually through the furcation to separate the roots and aid atraumatic removal.Figure 5. Tooth has been removed and the socket walls have been maintained, including the septal bone.Figure 6. Degranulation bur kit (Strauss & Co, Germany) used to clean the socket and ensure all granulation tissue has been removed, used with copious saline irrigation at 800rpm.
The osteotomy was initially prepared into the septal bone, verifying with a radiograph (Figure 7) and completed with osseodensification burs (Densah burs, Versah, USA) to allow for expansion of the site rather than removal of the bone. A conical implant with active threads (Megagen AnyRidge 5.0 x 10 mm with 4.0 mm core, Megagen, South Korea) was placed with an insertion torque of 50 Ncm (Figure 8). The head of the implant was placed in a sub-osseous position and submerged just over 4 mm from the gingival margin (buccally and palatally).
Figure 7. Radiograph showing pilot drill in place. Following initial pilot osteotomy, the position was altered to a slightly more mesial position following the information from this radiograph. A Lindermann bur (Osstem, South Korea) was used for this.Figure 8. Megagen AnyRidge Implant (5.0 x 10 mm) placed into the ideal position, into the septal bone. An insertion torque of 50 Ncm was achieved. The coronal head of the implant was sub-osseous and at least 4 mm deeper than the gingival margin from all aspects.
Prior to grafting of the sockets, a custom healing abutment was made. This was carried out by using a temporary titanium cylinder that was secured to the implant (Figure 9). Subsequently, flowable composite was applied from the cylinder to the gingival margins and incrementally light cured (Figures 10 and 11) until the socket was superficially sealed with composite. The idea here was not to allow the composite to flow down into the socket or contact the implant, therefore incremental curing of the composite was important.
Figure 9. Temporary titanium cylinder secured to the implant using the restorative screw provided.Figure 10. Flowable composite was incrementally applied to the cylinder, stopping at the gingival margins, to outline the shape of the socket.Figure 11. Flowable composite was applied to fill the spaces, ensuring that it did not flow down into the sockets or come into contact with the implant. Also ensuring there was space left mesially and distally for the papilla and to prevent it locking into the undercuts.
The custom healing abutment was removed, revealing an irregular/rough surface underneath (Figure 12). More flowable composite was added here (extra-orally) and light cured to set. The custom healing abutment was then shaped to reduce the convexity (Figure 13) and produce a more favourable concave shape, which was then highly polished with soflex discs (Figure 14) and the cylinder was shortened to the level of the composite (approximately 0.5–1 mm coronal to the soft tissue height).
Figure 12. The custom healing abutment was removed from the implant to reveal an irregular fit surface.Figure 13. The irregularities were filled with flowable composite, but this was too bulbous and would have compressed the underlying bone, not giving enough space for soft tissue growth.Figure 14. The fit surface shape was altered into a more concave shape using a rugby ball-shaped bur and soflex polishing discs to smoothen and polish.
The sockets were then subsequently grafted using an allograft (MinerOss cortico-cancellous, BioHorizons, USA) mixed with platelet-rich fibrin liquid (S-PRF, Choukroun PRF Process, France).7 Dual-zone grafting principles were employed, where the graft material was packed into the sockets to fill the bone and soft tissue zones.8 During this process, the implant carrier was placed into the implant to prevent any bone granules from entering the implant chamber (Figure 15).
Figure 15. The implant insertion tool was placed into the implant to prevent any graft material finding its way into the implant well, and the socket was grafted with allograft and PRF.
The custom healing abutment was then secured into the implant (ensuring the hex was engaged) and torqued to 25 Ncm, as per manufacturer guidelines. The access through the temporary cylinder was sealed with PTFE and composite. A crossed horizontal mattress suture was placed to pull over the custom healing abutment and vertical mattress sutures placed in the papilla sites, using 6-0 prolene (Figure 16). A post-operative radiograph was taken (Figure 17).
Figure 16. The custom healing abutment was secured into the implant, sealing over the graft. The access hole was sealed with PTFE and composite. Horizontal and vertical mattress sutures (6-0 prolene) were placed.Figure 17. Post-operative radiograph showing the implant in place, the graft material filling the sockets and the concave custom healing abutment holding the graft material in place.
Following a period of 3 months, the custom healing abutment was removed to reveal a widely formed emergence profile with stable soft tissue. This was helped by the graft material that was placed into the soft tissue zone and by the custom healing abutment, which helped to maintain the original socket outline and prevent collapse (Figure 18). An open tray impression was taken in a polyether impression material (Impregum, 3M, Seefeld, Germany) and the custom healing abutment was replaced, ensuring it was placed in the same position. After 2 weeks, the laboratory returned a screw-retained crown made using a titanium base and a zirconia core, supragingivally layered in lithium disilicate. All areas in contact with the soft tissue were prepared with highly polished zirconia (not glazed) for better soft tissue adherence (Figure 19).9,10 The crown was torqued to 35 Ncm, as per manufacturers guidance. The access was sealed with PTFE and composite (Figure 20); occlusal adjustments were made and a post-operative radiograph taken (Figure 21).
Figure 18. Mirror view of the LR6 site 3 months post operatively. A stable, wide emergence profile can be seen. The stability is helped by the graft materials placed in the soft tissue zone at the time of surgery.Figure 19. A screw-retained crown was made by cementing a custom-milled zirconia coping onto a titanium base, supragingivally layered in lithium disilicate. All areas in contact with the soft tissue were kept in zirconia, which was highly polished (not glazed) for better soft tissue adherence.Figure 20. Final restoration fitted onto the implant. The access hole can be seen occlusally, sealed with PTFE and composite. Note the level of the mid buccal gingival position and papilla infill.Figure 21. LCPA radiograph after the fitting of the definitive crown. Note the layering onto the zirconia is only supragingival.
Discussion
This case demonstrates the process for predictably placing a dental implant immediately into a molar socket. Some clinicians may feel that immediate implant treatments are higher risk and perhaps should be avoided in what may be a nonaesthetic site. However, we know from the research that these procedures have similar success rates to placing implants in healed sites.2,3 The benefit to the patient and the clinician is, of course, a reduced number of treatment visits and clinical time, which may not necessarily be the best reason for altering treatment protocols that have worked for many years. However, it is known that immediate implants also have the advantage of reducing post-extraction dimensional changes (when the conditions are right) and therefore has a positive effect on the final outcome.11,12 This is especially true when customized healing abutments or temporary crowns are made to take the shape of the perimeter of the sockets12 and act as socket sealing devices. Sealing the sockets helps to support the soft tissue architecture and prevent collapse of the soft tissue into the socket, as well as protecting the graft and clot in the socket, allowing for undisturbed healing.
A flapless approach with dual zone bone grafting of the jump gap (graft material filled beyond the bony part of the socket and taken up to the gingival margin) has been shown to produce a more stable soft tissue result,8 which not only ensures thicker more stable soft tissues around the implant restoration, but also reduces the chances of food packing, which can be a problem for molar implant crowns where implants have been placed in healed sites.
A common problem with immediate implants is a lack of primary stability, which will increase the chances of failure.13 Understanding the different molar socket types in relation to the septal bone, will allow for proper planning to help ensure that primary stability of the implant is achieved.6 This is a fundamental part of the treatment, because if primary stability is not achieved, then this will be more likely to lead to loss of the implant. Insertion torque values for immediately loaded implants have been described in the literature as needing to be over 30 Ncm.14,15 Although in this case, the implant was not loaded with a provisional crown, a custom healing abutment is similar to a short crown and therefore it would be prudent to ensure a high-enough insertion torque value to help prevent micromovements (must be under 100 μm) that would lead to failure.16
Other issues that may arise are the loss of the graft material and introduction of foreign bodies into the socket during healing. This is more likely in cases where the socket is not adequately sealed and can be especially problematic in type B and C sockets6 where parts of the implant would not be submerged in native bone. This is, of course, easily prevented by making the custom healing abutment as described in the method above, which will effectively seal the socket and prevent any disruption to the implant, graft or socket beneath. Owing to the time-consuming nature of making this socket sealing device, some clinicians may be tempted to use a stock healing abutment. Usually, however, the diameter and the shapes of these are not suitable for immediate molar implant treatments because they will not effectively seal the sockets, and increased incidence of failures will be found.17
Conclusion
Immediate molar implant treatments can be carried out predictably and produce excellent results. They have the advantage of reducing treatment time and the number of surgical procedures to just one. The wide soft tissue emergence that is achieved is important in protecting the implant long term (because the tissues are very thick) and also helps to prevent food trap under the crown, which can otherwise be a common problem for molar implants. However, understanding and following the protocols for immediate implants is key, especially when it comes to socket sealing with a custom healing abutment or temporary crown.
