The most challenging and time-consuming step in the free gingival graft (FGG) for keratinized mucosa augmentation is the compression suture anchoring the FGG to the periosteum. This article proposed a novel “microscrew with tie-down sutures” technique to anchor the FGG to the recipient site without the traditional trans-periosteum suture. This patient’s keratinized mucosa width (KMW) around the healing abutments of teeth #29 and #30 was less than 1 mm. After an apically positioned flap (AFP) was prepared, 2 microscrews were placed at the buccal plate of the alveolar ridge bone, which is the coronal margin of the AFP. Then, the sutures winded between the microscrews and the healing abutments to anchor the FGG. In conclusion, the “microscrew with tie-down sutures” technique offers a feasible and straightforward alternative for the trans-periosteum compression suture, mainly when the periosteum is fragile, thin, or injured.

Peri-implant tissues are more vulnerable to infection than periodontal tissues due to their unique biological constitution, which lacks Sharpey fibers, has fewer fibroblasts, and has reduced vascularity.1  The keratinized mucosa (KM) is the primary defense against bacteria invasion from peri-implant sulcus by providing a relatively tight fibrous collar around implant.2  Studies show the width of keratinized mucosa (KMW) is critical to maintaining long-term peri-implant tissue health. More than 2 mm of KMW around the implant is necessary to reduce soft-tissue recession, prevent bone loss, and promote adequate oral hygiene.3,4  In contrast, a KMW less than 2 mm is more susceptible to plaque accumulation and mechanical force such as toothbrushing, resulting in patient discomfort.5  Furthermore, a reduced KMW is a risk indicator for certain biological complications, such as peri-implant mucositis or peri-implantitis.6 

The sixth European Association for Osseointegration (EAO) Conference Consensus Report revealed that soft tissue augmentation is a valid treatment to increase KMW, which can significantly improve gingival index and plaque control and prevent mucosal recession.3  An apically positioned flap (ARP) combined with a free gingival graft (FGG) is the gold standard for augmenting the keratinized tissue.7,8  Stabilization of graft on the recipient site is the most critical procedure of FGG, requiring complicated and refined suture techniques, which is challenging to perform, especially in the posterior area. In addition, this complex suturing technique may result in periosteal tearing or breaking. Furthermore, suturing is the most time-consuming stage of FGG surgery, and prolonged surgery may result in more postoperative inflammation and pain.8  To solve these problems, a suture-less technique was proposed to simplify the surgical procedure using cellophane,9  bandage tape,10  tissue adhesives,11  and other related approaches. However, the long-term effectiveness of these bio-glues in maintaining the stability of the graft in complicated oral environments remains controversial.

Given these challenges, a novel “microscrew with tie-down sutures” technique was proposed to stabilize FGG on the recipient site as an alternative to the traditional suturing method. Through this technique, microscrews are placed at the buccal aspect to resist the movement of an apically positioned flap; then, the sutures are winded between the microscrews and the healing abutment to position the FGG on the recipient bed stably. This technique can simplify the FGG surgical procedure, shorten surgery time, and enhance KM around the implant more effectively.

A 65-year-old female had 3 missing teeth on the right side of the mandible for several years. The patient has reported compromised chewing function and unsatisfied esthetics due to missing teeth. Three implants were placed 3 months ago to replace missing teeth #s 29 (4.0 × 8 mm, Astra TX), 30 (4.0 × 6 mm, Astra TX), and 31 (4.0 × 6 mm, Astra TX) to address the patient’s concerns.

Chief complaints

The first stage of implant placement surgery was accomplished for 3 months, and the healing abutment of the implant of tooth #31 fell off, and that of tooth #30 was loosening.

Medical history

The patient denied having any systematic diseases or a history of smoking.

The patient denied having a relevant personal or family history.

Extraoral/Intraoral exam

The KMW around the healing abutments of teeth #s 29 and 30 was less than 1 mm. Debris adhering to the healing abutment of teeth #s 29 and 30 was obvious. The healing abutment of tooth #30 was loosening.

Radiography

Panoramic radiographs showed good osseointegration around implants #s 29, 30, and 31 (Figure 1).

Figure 1.

(a) Clinical photograph taken after implantation with non-submerged healing for 3 months, showing KM insufficiency of the implant of teeth 29 and 30. (b) Radiograph examination taken after implantation with nonsubmerged healing for 3 months (the loosening healing abutment of the implant of tooth 30 was taken off before taking X-ray examination).

Figure 1.

(a) Clinical photograph taken after implantation with non-submerged healing for 3 months, showing KM insufficiency of the implant of teeth 29 and 30. (b) Radiograph examination taken after implantation with nonsubmerged healing for 3 months (the loosening healing abutment of the implant of tooth 30 was taken off before taking X-ray examination).

Close modal

Final diagnosis

The patient was diagnosed with keratinized gingiva insufficiency of teeth #s 29, 30, and 31, as well as peri-implant mucositis of the implants of teeth #s 29 and 30.

Pre-treatment

To control peri-implant mucositis, minocycline was applied around implant #s 29 and 30 after saline irrigation once daily for 3 days. 0.05% chlorhexidine was prescribed and instructed to mouth rinse 3 times a day for 3 days as a home care modality.

ARP + FGG surgery was planned to increase the KMW to prevent future gingival recession and provide long-term gingival health. The patient was informed of a detailed treatment plan, the risks and benefits of the treatment, and possible post-surgery complications. After discussion, the patient agreed to proceed, and written consent was obtained.

Recipient site preparation

The patient was instructed to rinse her mouth with 0.05% chlorhexidine for 1 minute. Then, local sterilization was performed with iodophor disinfectant (PVP). Under local anesthesia, healing abutments were removed. The recipient bed was prepared with a horizontal mid-crestal incision using a #15 scalpel from the distal of the implant of tooth #29 to the distal papilla of the implant of tooth #31. Vertical incisions were made at both ends of the horizontal incision and extended apically beyond the mucogingival junction. The vertical releases were made carefully without damaging the nervus mentalis (Figure 2b). The buccal flap was elevated with partial thickness, while the periosteum was elevated at the apical part to cut off the muscle attachments completely. The flap was apically repositioned with three 1.5 × 8 mm microscrews (Figure 2b inserted) and fixed with single interrupted sutures around mini-screws and with apical periosteum. Then, the 3 healing abutments were replaced. With the microscrews stabilizing the buccal flap, a fence-like recipient bed with 15 mm length and 6 mm width was well prepared between healing abutments and apically positioned buccal flap (Figure 2).

Figure 2.

(a) Apically positioned flap. (b) Two microscrews were placed on the buccal plate, and the healing abutments were screwed on the implants of teeth 29, 30, and 31.

Figure 2.

(a) Apically positioned flap. (b) Two microscrews were placed on the buccal plate, and the healing abutments were screwed on the implants of teeth 29, 30, and 31.

Close modal

Graft harvesting from the donor site

After local sterilization and under infiltration anesthesia, the donor area was measured with a periodontal probe according to recipient site size (15 mm * 6 mm * 1.5 mm, length * width * thickness), and the graft contour was traced by scalpel at the maxillary palate between the first premolar and the first molar. The dissection was carried out using a #15 scalpel blade parallel to the epithelial following the graft tracing. The fat or gland tissue was removed after the FGG was successfully isolated and harvested. Then, the graft was stored immediately in a saline solution for future usage. The open wound at the donor area was protected by a collagen matrix, which was stabilized with crossed horizontal sling sutures (Figure 3).

Figure 3.

(a–c) Surgical process of FGG harvest from the right maxillary palatine. (d–f) Width, length, and thickness of the FGG measured by the periodontal probe.

Figure 3.

(a–c) Surgical process of FGG harvest from the right maxillary palatine. (d–f) Width, length, and thickness of the FGG measured by the periodontal probe.

Close modal

Graft immobilization

The graft was placed with its connective tissue facing against the periosteum of the recipient site and stabilized with single interrupted sutures to the periosteal bed mesially and distally using a 5-0 absorbable suture. Then, a 4-0 suture was used to tie down the graft by crossing the healing abutments and microscrews in the Figure 6 pattern. The knots were placed buccally. In the next step, figure pressure was applied with wet gauze over the FGG for a short time to establish intimate contact between the graft and periosteum of the recipient bed (Figure 4).

Figure 4.

(a) FGG was initially placed on the recipient site by 2 single interrupted sutures on the mesial and distal periosteal bed. (b) 4-0 suture was used to tie down the graft by crossing the healing abutments and the microscrews to immobilize the graft.

Figure 4.

(a) FGG was initially placed on the recipient site by 2 single interrupted sutures on the mesial and distal periosteal bed. (b) 4-0 suture was used to tie down the graft by crossing the healing abutments and the microscrews to immobilize the graft.

Close modal

Postoperative management

Prophylactic antibiotics (oral amoxicillin, 500 mg, TID and metronidazole, 300 mg TID) were prescribed for 2 days. In addition, the patient was instructed not to brush the surgical site for the first 2 weeks but to rinse with 0.05% chlorhexidine mouthwash 3 times a day.

Outcome and follow-up

Fourteen days after surgery, the follow-up exam showed FGG recovered well without any sign of infection or necrosis. Slight erythema was observed at the edge of FGG, which is determined to be a normal healing process. The wound at the donor site appeared to be well-healed with a slightly red manifestation. Thus, all sutures were removed on that day (Figure 5a, b, and c).

Figure 5.

(a) Clinical photograph of the recipient site taken on day 14 after operation. (b) FGG survived, and the edge of the wound at the recipient site was still red and swollen on day 14 after operation. (c) Clinical photograph of the donor site taken on day 14 after operation. (d) Clinical photograph of the recipient site taken 1 month after operation. (e) KM around the implant-supported crown was stable and healthy after final restoration at the 1-year follow-up. (f) Radiograph examination taken after final restoration at the 1-year follow-up.

Figure 5.

(a) Clinical photograph of the recipient site taken on day 14 after operation. (b) FGG survived, and the edge of the wound at the recipient site was still red and swollen on day 14 after operation. (c) Clinical photograph of the donor site taken on day 14 after operation. (d) Clinical photograph of the recipient site taken 1 month after operation. (e) KM around the implant-supported crown was stable and healthy after final restoration at the 1-year follow-up. (f) Radiograph examination taken after final restoration at the 1-year follow-up.

Close modal

One month after surgery, the healing of the recipient site was complete. The keratinized gingiva around the healing abutment was sufficient and consistent with the surrounding tissue (Figure 5d). It is determined that the implants are ready to be restored. The final impression was taken at the same appointment. Then, 3 individual screw-retained implant-supported ceramic crowns were fabricated to restore the missing teeth.

One year after the final restoration, the follow-up examination demonstrated that the KM around the implant-supported crown was stable and healthy, without apparent shrinkage (Figure 5e). The marginal bone around implants #s 29, 30, and 31 was also stable, as reflected by panoramic radiograph examination (Figure 5f).

KM can improve resistance to bacterial pathogens, stabilize the gingival margin position, and positively influence the long-term health of peri-implant tissue.12  A lack of KM around implants leads to more plaque accumulation, inflammation of soft tissue, attachment loss, and a higher risk of peri-implantitis.5,13–15  It has been suggested that the presence of KM around the implant needs to be at least 2 mm.3,4 

Advanced soft tissue augmentation techniques are often required due to the absence of KM around implants.16,17  As a reliable treatment strategy, the combination of ARP and FGG was reported to gain KMW with various ranges from 1.15 ± 0.81 mm to 2.57 ± 0.50 mm.18  The surgical procedures include an apically positioned split flap with the application of autogenous tissue (FGG) or soft tissue substitutes, such as a collagen matrix.19  The critical points for this procedure are stable fixation of apically positioned split-flap and grafting tissues to the recipient site.

Previous studies reported that unstable fixation is one of the common complications causing failures.20  Fixation suturing requires good accessibility, limited in the posterior zones, and great surgical experience and delicacy. Traditionally, the graft was fixed to the proximal base of the periosteum using interrupted sutures and then anchored to the periosteum of the recipient area using crossed horizontal mattress sutures (Figure 6a). Due to the fragile nature of the periosteum, this suturing procedure requires costly materials, a significant amount of time, and experienced clinicians, which are not accessible in some remote areas, limiting the application of these procedures. And, if the periosteum is accidentally torn, the vascularization will be interrupted, which reduces the grafting success rate. Thus, previous studies have reported a suture-less technique using bio-glue to simplify the graft fixation procedure.9–11  However, bio-glue has several challenges that have not been overcome, such as its resistance to muscle movement during the prolonged healing period and biological degradation in a complicated environment with bioactive enzymes and bacteria.

Figure 6.

(a) Schematic of the traditional FGG suturing technique. (b) Schematic of the “microscrew with tie-down sutures” technique to immobilize the graft.

Figure 6.

(a) Schematic of the traditional FGG suturing technique. (b) Schematic of the “microscrew with tie-down sutures” technique to immobilize the graft.

Close modal

This study proposed a new surgical strategy to simplify the traditional suturing technique by using widely/commonly available surgical instruments and materials. Microscrews were used to stabilize the slip-flap at the apical position, which reduced the AFP coronal shift and increased its stability. In addition, instead of suturing the FGG to the fragile periosteum, the investigators took advantage of the fence-like structure (constituted of the healing abutment and microscrews) to fix the FGG on the periosteum via tie-down suture technique (Figure 6b). The sutures were centered on the microscrew and tied across the healing abutment in a fan pattern to immobilize the FGG on the periosteum. These sutures pressed on the graft aimed to minimize the dead space between the recipient site and the graft and ensure rapid revascularization during the integration process. In this case, the short-term success of the graft was observed 2 weeks after the operation, and the long-term success was confirmed at a 1-year follow-up, confirming that KM around the implant-supported crown was stable and healthy. It was reported that FGG around implants shrank by 24.76% to 44.4% in the posterior regions according to the 6-month follow-up.21,22 

Compared to the traditional FGG suturing method, the “microscrew with tie-down sutures” technique has several advantages. First, for some cases of fragile, thin, or damaged periosteum, where the anchorage suture is impossible, the “microscrew with tie-down sutures” technique is a feasible alternative for the compression suture anchored to the periosteum. Secondly, winding the sutures between the healing abutments and microscrews is easier to carry out than suturing the graft precisely on the periosteum, significantly increasing the graft success rate for doctors with less surgical experience. Third, this simplified technique can reduce time, lower the risk of infection, and decrease patient morbidity. Lastly, it increases the resistance to the coronal shift of AFP caused by buccal mucogingival movement during speaking or chewing. Hence, the “microscrew with tie-down sutures” technique presented in this study demonstrates an improvement in FGG augmentation surgery for increasing KMW around implants.

The “microscrew with tie-down sutures” technique has drawbacks and shortcomings. Firstly, more sutures in the surgery area tend to accumulate food debris and may affect wound healing. Secondly, the screw may lead to the discomfort of the patient. Furthermore, once the microscrew dislodges, the sutures may be loosened, leading to surgical failure.

The “microscrew with tie-down sutures” technique presents a feasible, simplified, and problem-solving resolution for enhancing KM around the implant in the posterior area. Future studies on this technique should include additional cases and longer tracking times.

Abbreviations

Abbreviations
ARP

Apically positioned flap

FGG

Free gingival graft

KM

The keratinized mucosa

KMW

The keratinized mucosa width

PVP

Iodophor disinfectant

Anbin Xu and Tao Wu contributed equally to this work. The authors declare no conflict of interest for this study. This project was supported by the United Fund of Innovative and developmental NFSC project (2022CFD005).

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