Dental implants that are placed immediately into carefully selected extraction sockets have high survival rates comparable to implants placed in healed sites¹⁾. Of course, alveolar bone and soft tissue may be insufficient for implant placement, but advances in technique have made it possible to restore masticatory function through implant placement in almost any unfavorable situation, provided there are no time or financial constraints. Nevertheless, a series of surgeries for implants can be painful, swollen, and frightening for patients, and surgeons are faced with multiple surgeries or invasive procedures under unfavorable conditions. Surgical protocols are being researched and clinically applied to reduce operative time and minimize post-operative discomfort in healthy patients as well as the increasing number of elderly and systemically ill patients.

In 3 cases of maxillary molars with extensive bone destruction secondary to periodontal disease, we tried a different approach to surgery using an implant with a special design & structure named MagiCore (InnoBioSurg Co., Ltd., Daejeon, Korea). The MagiCore implant can be divided into three parts (Fig. 1). It is a one-body implant that can be divided into Magic fin thread, which has a thin core with Resorbable Blast Media (RBM) surface treatment and a thin and long thread located inside the alveolar bone; Magic Cuff, which has 2 mm, 3 mm, 4 mm, 5 mm lengths that can be selected according to the thickness of various soft tissues (gingival thickness＋alveolar bone height of deficient width=thickness of soft tissue); and Magic post, which has a double connection structure that can hold the fixation of the prosthesis inside and outside. Thin, long fin threads achieve initial fixation through morphologic contact with the residual bone rather than fixation through compression, although good initial fixation can be achieved with thin residual bone. Based on a 5.5 mm diameter MagiCore implant, the core body diameter is 3.3 mm and the unilateral fin thread length is 1.1 mm. The Magic cuff has soft tissue affinity with its machined surface, is thin compared to the diameter of the implant, which can be expected to create a platform switching effect, reduces the interface with soft tissue where the implant penetrates into the oral cavity, and has the morphological advantage of obtaining thicker soft tissue around the implant. Using the concept of secondary wound healing without forming a flap, we would like to present 3 cases where implant placement and bone grafting were performed through the extraction socket with good results.

Figure 1. The MagiCore implant consists of three parts: the Magic Post, the Magic Cuff, and the Magic Fin Thread.

1. Case 1

This is a 49-year-old female patient who presents with a chief complaint of maxillary left posterior crown & bridge mobility. It was expected that maxillary left second molar (#27) would show vertical and horizontal defects of alveolar bone (Fig. 2A∼C) through spontaneous healing after tooth extraction, so a bone graft was performed at the same time as the implant placement. After tooth extraction (Fig. 3A), the inflammatory granulation tissue was cleaned out and the mature granulation tissue was used as a substitute for the deficient soft tissue (Fig. 3B). The maxillary sinus floor and maxillary sinus membrane were then elevated using a MAGIC EXPANDER (Fig. 2C) and an osteotomy was performed. A Freeze Dried Bone Allograft (FDBA) containing cortical & cancellous bone particle of 0.3 mm to 0.8 mm size was grafted under mature granulation tissue and in the extraction socket, a guide hole was established, and a motor was used to place it. The implant was placed with a diameter of 5.0, a 3 mm length magic cuff, and a 13 mm length implant (Fig. 2D, E). At implant placement, the initial torque value (ITV) was 15 N.Cm and the ISQ was 51/51. After implant placement, the creation and maintenance of a blood clot triggered secondary healing of the tooth and soft tissues (Fig. 3C, D). Final prosthesis was delivered at 5.5 months post-op. after confirming the clinical findings and ISQ values (Table 1, Fig. 4A, B), and panoramic and clinical photos at 11 months post-op show good results (Fig. 4C, D). In the CT image changes with time, vertical augmentation of the alveolar bone on the palatal side and regeneration of a sufficient amount of alveolar bone around the implant can be observed. In the CT image at 11 months postoperatively, the cortical line of the alveolar bone on the palatal side and buccal side becomes clear, the boundary between the existing bone and the generated bone becomes indistinct, and the maturation of the grafted bone can be observed (Fig. 5).

Table 1 . Changes of secondary stability over time in Case 1

	OPD	PO 6W	PO 12W	PO 21W	PO 24W
ISQ Value	51/51	30/39	41/44	51/51
Procedure				Final Cr. Imp.	Final Cr. set

OPD: Operation Date, PO: Postoperative, W: Week, Cr.: Crown, Imp.: Impression.

Figure 2. Radiographic findings, diagnostic process and postoperative radiographs. (A) Initial panorama. (B) Digital surgery with initial CT view. (C) Digital surgery after extraction on OPD. (D) Postop. panorama. (E) Implant-centered CT view after surgery.

Figure 3. Surgical photos and soft tissue healing. (A) Mature granulation tissue is seen on the palatal side. (B) Guide pin placement. (C) Postoperative view showing loose sutures. (D) Healing of #27 at 5.5 months postop.

Figure 4. Clinical and panoramic photos after prosthetics. (A) Occlusal view at 5.5 months postop. (B) Buccal view at 5.5 months postop. (C) Panoramic view at 11 months postop. (D) Buccal view at 11 months postop.

Figure 5. According to time, change of CT view. (A) After implantation. (B) 5.5 months after implantation. (C) 11 months after implantation. Red line: connecting line between buccal and lingual alveolar height.

2. Case 2

This is a 53-year-old male patient presenting for extraction and implantation of a maxillary right first molar (#16). The patient has clinically swelling of the buccal gingiva and significant alveolar bone destruction on panoramic and CBCT radiographs (Fig. 6A, B). Antibiotics and anti-inflammatories were prescribed after the cleaning to reduce the discomfort caused by periodontitis and to relieve the acute inflammatory condition. The surgical procedure was done the same as the above case. The implant was placed with a diameter of 5.5, a 3 mm length magic cuff, and an 11 mm length implant (Fig. 6C, D). At implant placement, the initial torque value (ITV) was 15 N.Cm and the ISQ was 42/42. Secondary healing of the soft tissues was induced and healed well without any specific problems (Fig. 7B∼D). Final prosthesis was delivered at 7.5 months post-op after confirming the clinical findings and ISQ values (Table 2, Fig. 8A, B). A good appearance is observed in the panoramic photograph taken at 18 months post-op and a mature and stable gingival tissue is observed in the clinical photograph taken at 19 months post-op (Fig. 8C, D). Changes in the CT images with time show horizontal and vertical regeneration of the lost alveolar bone, indistinct boundaries between the grafted allograft and the original, increased radiopacity, and the creation of a cortical bone border on the palatal side of the alveolar bone (Fig. 9).

Table 2 . Changes of secondary stability over time in Case 2

	OPD	PO 6W	PO 13W	PO 29W	PO 30W	PO 35W	PO 36W
ISQ Value	42/42	44/52	48/56	57/61		62/65
Procedure				Temporary Cr. Imp.	Temporary Cr. set	Final Cr. Imp.	Final Cr. set

OPD: Operation Date, PO: Postoperative, W: Week, Cr.: Crown, Imp.: Impression.

Figure 6. Initial radiographic findings, diagnostic process and postoperative radiographs. (A) Initial panorama. (B) Digital surgery with initial CT view. (C) Postoperative panorama. (D) Implant-centered CT view after surgery.

Figure 7. Secondary wound healing and granulation tissue maturation. (A) Clinical picture after surgery. (B) Clinical picture at 8 days after surgery. (C) Clinical picture at 3 months after surgery. (D) Gingival condition just before final setting.

Figure 8. Clinical and panoramic photographs after prosthesis. (A) Occlusal view at 11 months postop. (B) Buccal view at 11 months postop. (C) Panoramic view at 18 months postop. (D) Buccal view at 19 months postop.

Figure 9. According to time, change of CT view. (A) 8 days after implantation. (B) 8 months after implantation. (C) 18 months after implantation. Red line: connecting line between buccal and lingual alveolar height.

3. Case 3

This patient presented to our office with pain and swelling in the maxillary right first molar (#16) and had been undergoing multiple periodontal treatments. A patient comes in with “swollen gums and pain when chewing” and has a tooth extraction and implant placement the same day. Radiographic findings show extensive horizontal and vertical bone destruction on the buccal and palatal sides of #16 (Fig. 10A, B). The procedure was performed in the same way as the above cases, and the implants were placed with a diameter of 6.0, a 4 mm length magic cuff, and an 11 mm length implant (Fig. 10C, D). At implant placement, the initial torque value (ITV) was 30 N.Cm and the ISQ was 56/56. The same method was used to induce secondary healing of the soft tissue (Fig. 11). Final prosthesis was delivered at 4.5 months post op. after confirming the clinical findings and ISQ values (Table 3, Fig. 12A, B). He has good clinical and radiographic outcomes at 32 months post op (Fig. 12C, D). CT image changes over time up to 32 months postoperatively show horizontal and vertical regeneration of the lost alveolar bone, formation of a new border in the maxillary sinus, formation of a new cortical line on the buccopalatal side, loss of the boundary between the original bone and the grafted bone, and increased radiopacity with maturation of the grafted bone (Fig. 13).

Table 3 . Changes of secondary stability over time in Case 3

	OPD	PO 11W	PO 14W	PO 19W	PO 20W
ISQ	56/56	66/66	65/65
Procedure		Temporary Cr. Imp.	Temporary Cr. set	Final Cr. Imp.	Final Cr. set

OPD: Operation Date, PO: Postoperative, W: Week, Cr.: Crown, Imp.: Impression.

Figure 10. Initial radiographic findings, diagnostic process and postoperative radiographs. (A) Initial panorama. (B) Digital surgery with initial CT view. (C) Postoperative panorama. (D) Implant-centered CT view after surgery.

Figure 11. Delayed healing process after blood clot dislodgement due to heavy smoking. (A) After extraction. (B) Sutured state after surgery. (C) After stitch out. (D) 26 days after surgery. (E) 35 days after surgery. (F) 3 months after surgery.

Figure 12. Clinical and panoramic photographs after prosthesis. (A) Occlusal view at 4.5 months postop. (B) Buccal view at 4.5 months postop. (C) Panoramic view at 32 months postop. (D) Buccal view at 32 months postop.

Figure 13. According to time, change of CT view. (A) After implantation. (B) 4.5 months after implantation. (C) 32 months after implantation. Red line: connecting line between buccal and lingual alveolar height.

When placing an implant after a tooth has been extracted, the probability of failure varies depending on the cause of the extraction. It is known that the probability of failure is higher for implants in periodontally diseased areas due to infection and failure of osseointegration rather than caries, tooth fracture, or bone destruction of endodontic origin²⁾. All three cases are patients with periodontal disease who underwent extractions and implants, and except for case 3, had not received regular checkups and management. Nevertheless, in all 3 cases, implant placement with bone grafting was performed after extraction.

In a case with severe bone destruction due to periodontal disease, I think the approach of not forming a flap, performing an osteotomy for the implant installation through the extraction site, elevation of the sinus floor, not using a barrier membrane, using allograft only, placing the implant immediately, and inducing secondary wound healing without performing primary closure is a very different approach from the traditional one. In the presence of severe bone destruction, primary closure was considered essential to achieve the outcome of GBR with bone graft and barrier membrane. However, good results were achieved by placing the implant with bone grafting without membrane at the tooth extraction, without incision of the soft tissue, and secondary wound healing in which the deficient soft tissue is healed from blood clots.

In all cases, there was little residual bone for initial fixation of the implant, only allogenic bone was used for repair of extensive bone defects, mature chronic granulation tissue was used for deficient soft tissue, and no additional soft tissue incisions were performed. It also induced secondary wound healing without insisting on primary wound closure. In cases 1 and 2, soft tissue healing was obtained with good secondary wound healing. But, in case 3, the patient’s cooperation was poor and he was a heavy smoker, which resulted in exfoliation of the blood clot between the implant and the soft tissue, delaying soft tissue healing and requiring periodic checks and hygiene control. Good results were achieved as the blood clot stabilized on the surface of the grafted allograft.

Only allogenic bone was used in areas with extensive bone destruction due to periodontitis. Allogenic bone is considered the best bone graft material except for autologous bone. Allogenic bone has the advantages of being biocompatible, commercially available, resistant to infection, osteoinductive, and osteoconductive. The disadvantages include rapid absorption and a high rate of resorption at the grafted site. However, in all three cases, I wanted the graft material to be biocompatible and resistant to infection, to help stabilize blood clots in the grafted space, and to be replaced by new autogenous bone through rapid graft resorption. The most suitable graft material for this is autogenous cancellous bone, but since it requires an additional surgery, allogenic bone was used.

Wang et al.³⁾ published 4 major biologic principles (PASS) to achieve predictable bone regeneration. 1) Primary wound closure, 2) Angiogenesis, 3) Space maintenance/creation, 4) Stability of wound and implant. These cases were done using secondary wound healing, so may require patient assistance or additional interventions to stabilize the wound. We do not dissect the soft tissue and periosteum for angiogenesis, and space maintenance/creation is achieved by bone grafting into the extraction socket, no soft tissue dissection, suture with no pulling. Also an intact periosteum can also function as a great barrier membrane and help to keep space. So we think we can achieve favorable results compared to conventional procedures.

In an experiment designed to explore the role and importance of the periosteum in periodontal regeneration, Cho et al.⁴⁾ found that when the periosteum in areas where flap elevation was performed or bone defects were formed was compared to normal periosteum, the healed periosteum was thinner and the gingiva was thicker. I think it’s an indication that flap elevation can lead to periosteal atrophy and decreased blood supply, which can impede healing. If the wound is open at the site where the periosteal reflection, vertical incision, periosteal releasing incision for primary wound closure was performed, I believe that the periosteum, which is one of the sources of blood supply, may be detached or incised, resulting in unfavorable blood supply and contraction of the pulled soft tissue out. However, the surrounding soft tissues that do not elevate the periosteum, such as this surgery, show tissue contraction towards the center of the tooth extraction site and maintain their original blood supply, and the various lengths of the MAGIC CUFF are selectable according to the thickness of the soft tissue and have soft tissue affinity, so it seems to show good healing results.

Space maintenance for bone regeneration was achieved with grafted bone, an installed implant with long fin threads, and intact alveolar mucosa that could stably wrap around the space. We do not want the grafted bone to remain for a long time as a skeleton for new bone growth. The purpose of grafted bone is to maintain space, help stabilize the blood clot in the grafted area so that new autologous bone can be generated from the blood clot, and to provide autologous bone to fill the space of allogeneic bone that is rapidly resorbed. For this reason, blood supply from the periosteum, which is not blocked by a membrane, and blood supply from the residual bone are very important factors in the bone grafted area.

In order to overcome poor conditions such as the present case with minimally invasive surgery, it is important to be able to get sufficient initial fixation despite insufficient residual bone. In addition, the adhesion of the implant with soft tissue healed secondary to blood clots should create an environment that allows for regeneration and remodeling at the grafted site. We used the MagiCore implant, a one-body implant with long fin threads and wide inter-thread distance that can achieve fixation in thin residual bone, with a machined surface that has an affinity for soft tissue, and with no connecting structure under ahesion part with soft tissue, especially connective tissue.

In a case with severe bone destruction, thin residual bone, and insufficient soft tissue for primary closure, implant placement through an extraction socket, combined with extensive bone grafting simultaneously, but secondary wound healing resulted in a good outcome. We believe that we can reduce the number of surgeries by placing the implant with tooth extraction simultaneously, simplify the surgery by not making additional incisions, reduce the operation time, and reduce the postoperative discomfort for the patient.

In a variety of cases with severe bone destruction, we are seeing good results with immediate implant placement with bone grafting without flap elevation. We believe that a minimally invasive surgical approach that minimizes incisions, reduces operative time, and reduces the number of operations, thereby minimizing patient discomfort as well as minimizing the surgeon’s burden, is beneficial to both the patient and the surgeon. Although not applicable in all cases, efforts should be made to develop minimally invasive surgical procedures and methods.