Ⅰ. Introduction

Implant failure is generally categorized based on its timing.¹ Failure occurring before or during the abutment connection is classified as an early failure, which is typically attributed to inadequate osseointegration during the healing process. In contrast, failures that occur after implant occlusal loading are considered late failures and often result from the inability to sustain previously established osseointegration.²

Several treatment options are available for managing implant failure, including implant replacements, short-arch restorations, fixed partial dentures, removable dentures, and tooth-supported removable partial dentures.³ Many patients favor implant treatments because of their benefits in preventing bone loss⁴ during restoration, maintaining the stability and function of adjacent teeth, enhancing functionality for speaking⁵ and chewing,⁶ and providing a more natural appearance and feel.⁷

Following implant failure, however, bone resorption can lead to a narrowed ridge, which poses complications for subsequent implant placement, such as dehiscence or perforation. These defects threaten the long-term stability and success of the dental implants.⁸ Therefore, ridge reconstruction is considered a valuable intervention for preserving the alveolar bone and increasing the likelihood of successful implantation.⁹

This study presents a procedure utilizing horizontal guided bone regeneration (GBR) to facilitate successful implant placement at a site where previous implant surgeries have failed.

Ⅱ. Case Report

1. Initial examination

A 69-year-old male patient visited Seoul National University Dental Hospital in April 2020 seeking an implant for a right mandibular posterior tooth (#46) that had previously been removed owing to early implant failure. Upon examination, a narrow alveolar ridge and depression on the labial side were evident at the site (#46) (Fig. 1A and 1B), both of which result from early implant failure. Based on the systematic review by Benic and Hämmerle,¹⁰ the bone defects were classified as class II dehiscence defects.

Cone-beam computed tomography (CBCT; Fig. 1C and 1D) suggested that more than half of the implant diameter was exposed owing to considerable horizontal bone loss. Consequently, horizontal GBR using bone graft material and an absorbable collagen membrane was planned in conjunction with implant placement.

Fig. 1.

Preoperative clinical and radiographic assessment of the right mandibular posterior tooth (#46). (A) Clinical image showing a narrow alveolar ridge and labial depression at site #46, which resulted from early implant failure, (B) Periapical X-ray image of site #46, (C) Preoperative cone beam computed tomography (CBCT) image in the sagittal view, (D) Preoperative CBCT image in the coronal view.

2. Surgical procedures

Before each surgery, the patient was either gargled with 0.12% chlorhexidine gluconate solution for 30 s or had his mouth disinfected with a povidone-iodine swab. The skin around the surgical site was disinfected with a chlorhexidine swab, and a sterile surgical drape was applied to prevent potential contamination from external sources.

An intrasulcular incision and a horizontal incision above the alveolar crest were made from the distal line angle of tooth #44 to the distal line angle of tooth #47. An atrophied alveolar ridge was evident after flap elevation (Fig. 2A). An implant fixture (Osstem TS III SA; Osstem Co., Ltd., Seoul, Korea) with a diameter of 5 mm and length of 8.5 mm was placed at site #46 (Fig. 2B). To address this defect, a pre-shaped absorbable collagen membrane (Bio-Gide; Geistlich Pharma AG, Wolhusen, Switzerland) was applied, followed by the placement of deproteinized bovine bone mineral (DBBM; Bio-Oss, Geistlich Pharma AG, Wolhusen, Switzerland). The graft material was then covered with an absorbable membrane (Fig. 2C). The surgical site was closed using a horizontal mattress and simple interrupted with 5/0 Monosyn sutures (Braun, Melsungen, Germany) (Fig. 2D).

Fig. 2.

Surgical procedures for implant placement and guided bone regeneration (GBR) at site #46. (A) Clinical image of the atrophied alveolar ridge following flap elevation, (B) Implant fixture (Osstem TS III SA, 5.0 × 8.5 mm) placed at site #46, (C) Application of an absorbable collagen membrane (Bio-Gide) and deproteinized bovine bone mineral (DBBM; Bio-Oss) to address bone defects, (D) Closure of the surgical site using a horizontal mattress and simple interrupted sutures, (E) Clinical image taken 2 weeks postoperatively, showing complete suture removal and no signs of infection or swelling, (F) Clinical image taken 4 weeks postoperatively, demonstrating an upward shift of the mucogingival junction (MGJ) owing to GBR. Dotted line: mucogingival junction, (G) Periapical X-ray image of site #46 4 weeks postoperatively, (H) Clinical image taken 1 week after the second-stage surgery showing the removal of all sutures, with no signs of infection or swelling, (I) 6 weeks postoperatively, a clinical image shows soft tissue healing around the implant site. Dotted line: MGJ, (J) Periapical X-ray image of site #46 6 weeks postoperatively, (K) Final clinical image showing healthy peri-implant mucosa without signs of inflammation after final prosthesis placement. (L) Postoperative radiographs revealing stable bone levels with no evidence of bone loss.

Post-operative medications were prescribed, including cefdinir (100 mg, three times a day for 5 days) to prevent infection, ibuprofen (200 mg, three times a day for 5 days) to manage pain, and 0.12% chlorhexidine gluconate mouthwash to prevent plaque buildup at the surgical site and surrounding areas until suture removal. The patient exhibited no signs of swelling or infection and all sutures were removed 2 weeks later (Fig. 2E). As GBR was performed at site #46, the mucogingival junction (MGJ) shifted upward (Fig. 2F and 2G). Consequently, a second implant surgery was planned using an apically positioned flap to properly position the tissue during suturing.

A crestal incision and a vertical incision were made at site #46, with the crestal area elevated using a full-thickness flap and the buccal area elevated using a partial-thickness flap. A healing abutment measuring 6.0 × 5.0 mm was connected to the implant fixture. The flap was repositioned apically and sutured with 5/0 Monosyn (Braun, Melsungen, Germany). The patient was prescribed the same medications to prevent infection and inflammation.

The patient exhibited no signs of swelling or infection, and all sutures were removed 1 week after surgery (Fig. 2H). 6 weeks postoperatively, soft tissue healing was evident (Fig. 2I and 2J), and the patient was referred to the prosthodontics department for the fabrication of a prosthesis over the implant. The patient did not report any adverse reactions such as foreign body sensations, pain, or abnormal sensory responses (Fig. 2K).

During the intraoral clinical examination, healthy mucosa around the implant was evident with no signs of inflammation, such as purulence, edema, or rash. Additionally, radiographs taken after the final prosthesis was connected showed no evidence of bone loss (Fig. 2L).

Ⅲ. Discussion

In the present case, the successful replantation of a dental implant at a site with previous implant failure underscored the importance of addressing bone defects with GBR. Additionally, this case highlights the restoration of the keratinized peri-implant mucosa, which had diminished owing to early implant failure and GBR.

Factors contributing to early implant failure include smoking, location in the posterior maxilla, a history of periodontal problems, type IV bone, bone augmentation, and immediately loaded implants.¹¹ Other factors such as operator inexperience, excessive surgical trauma, bacterial contamination, and premature overload from micromotion during healing can also lead to failure.² In the present case, early failure likely resulted from a history of periodontal problems, excessive surgical trauma, and micromotion during the healing phase, which could have led to osseointegration.

Identifying and addressing the potential causes of implant failure at the outset is crucial. Following failure, a thorough analysis of the contributing factors is critical to develop an appropriate treatment approach to optimized outcomes. Previous research suggests that if an implant fails and is removed, a new implant can be placed in the same area after 9–12 months.¹² In this case, replantation occurred approximately 10 months after the initial failure. The implant site presented a class II defect with a reduced ridge width, which led to dehiscence when the implant was positioned. A systematic review¹⁰ suggests that volumetric stability in such defects is best maintained using absorbable membranes with particulate bone substitutes. In this case, the use of DBBM and an absorbable collagen membrane in GBR was effective in restoring adequate bone volume for stable implant placement.

An important aspect of the present case was the replantation of the implant at a previously failed site. A previous study reported a 71% survival rate for single dental implants replacing previously failed implants, with a mean follow-up period of 19.4 ±11.4 months.¹³ These findings emphasize the challenges associated with replantation and the need for meticulous planning and execution.

Studies on the use of DBBM have demonstrated that bone augmentation procedures typically require a healing period of 7–10 months, as supported by clinical and histological evidence.^14,15 In the present case, the interval between GBR and healing abutment connection was 7 months. Regenerated bone formation was confirmed in the buccal area where GBR was performed during the second implant surgery (Fig. 2G).

The keratinized peri-implant mucosa, initially lost owing to early implant failure and GBR, was established through apically positioned flap surgery during the healing abutment connection. A recent consensus indicated that reduced width of the keratinized peri-implant mucosa is associated with increased biofilm accumulation, soft tissue inflammation, patient discomfort, mucosal recession, marginal bone loss, and a higher incidence of peri-implantitis.¹⁶

The limitations of this case report include the absence of postoperative and post-prosthetic CBCT images difficulty in histologically confirming the regenerated bone, and a relatively short follow-up period. Long-term follow-ups are necessary to fully evaluate the stability and outcomes of this treatment approach.

Ⅳ. Conclusion

The present case demonstrated that horizontal bone grafting using GBR can effectively address bone defects following early implant failure, thereby enabling successful replantation. The patient experienced a favorable outcome with no signs of infection, inflammation, or bone loss, supporting the viability of this approach in similar clinical scenarios.