Vascularized interpositional periosteal connective tissue flap: A modern approach to augment soft tissue.

CONTEXT: Nowadays esthetics plays an important role in dentistry along with function of the prosthesis. Various soft tissue augmentation procedures are available to correct the ridge defects in the anterior region. The newer technique, vascularized interpositional periosteal connective tissue (VIP-CT) flap has been introduced, which has the potential to augment predictable amount of tissue and has many benefits when compared to other techniques. AIM: The study was designed to determine the efficacy of the VIP-CT flap in augmenting the ridge defect.
MATERIALS AND METHODS: Ten patients with Class III (Seibert's) ridge defects were treated with VIP-CT flap technique before fabricating fixed partial denture. Height and width of the ridge defects were measured before and after the procedure. Subsequent follow-up was done every 3 months for 1-year. STATISTICAL ANALYSIS USED: Paired t-test was performed to detect the significance of the procedure.
RESULTS: The surgical site healed uneventfully. The predictable amount of soft tissue augmentation had been achieved with the procedure. The increase in height and width of the ridge was statistically highly significant.
CONCLUSION: The VIP-CT flap technique was effective in augmenting the soft tissue in esthetic area that remained stable over a long period.

INTRODUCTION

The prosthetic replacement of the missing tooth should be in harmony with the adjacent natural dentition to fulfill esthetic demand of the patient, especially in the anterior region. However, alveolar bone resorption following tooth loss results in alveolar ridge defect and hampers the goal.[1]

The high incidence of residual ridge defect has been found following anterior tooth loss; majority of which is Class III defect.[23]

Normally, the height and width of residual ridge should allow placement of pontic that appears to emerge from the ridge and mimics the appearance of the neighboring teeth. However, such residual ridge contours sometimes lead to unaesthetic open gingival surfaces (black triangle), food impaction, and percolation of saliva during speech.[45]

Deficient ridges are treated either through soft[567] or hard tissues[89] or combination of both.[10] Description of techniques of tissue augmentation with onlay grafts, pedicle grafts or with allografts has been done from years.[11]

The selection of the surgical treatment also depends on the type of prosthetic treatment. When a fixed partial denture (FPD) is planned, soft tissue augmentation may be sufficient to solve ridge defects.[1] A novel pedicle autograft, vascularized interpositional periosteal connective tissue (VIP-CT) flap has been introduced for predictable large soft tissue augmentation in a single procedure. Excellent blood supply, less morbidity, primary closure of donor and recipient bed are the additional advantage of this flap. Furthermore, it does not alter the color of the area and is more agreeable to the patient because it involves a single surgical site.[1213] This study was undertaken to evaluate the efficacy of VIP-CT flap in augmenting the ridge defect.

MATERIALS AND METHODS

Ten subjects of which six were male and four were female [Table 1] in the mean range of 25-60 years of age (mean age 43.5 ± 8.53) with Seibert's Class III alveolar ridge defects were included in the present cohort study. All patients were periodontally healthy. The reasons for tooth extraction were endodontic failure and caries lesions combined with root or crown fractures. No tooth was removed because of advanced periodontal disease. All patients were in good health, with no contraindications for periodontal surgical therapy. Plaque and bleeding index were taken [Table 2].[1415] Fixed prosthetics was planned for all patients.

Table 1

Patient characteristics

Table 2

Plaque index and sulcus bleeding index at baseline

The investigation was approved by the Concerned ethical commity. All the participants signed an informed consent form before the start of the study. Clinical parameters recorded were the height and width of the ridge defects before and after the procedure. All clinical measurements were performed by the same examiner. Preoperative photographs were taken [Figures 1 and 2]. The procedure was accomplished in a similar manner to that described by Sclar.[12] An acrylic stent was fabricated for each patient to assist in the standardization of all measurements. The stent was designed to cover occlusal surfaces of the teeth adjacent to the augmentation site. Each stent has the indelible position marker to easily identify the predetermined points on the edentulous ridge where the height and width measurements would be taken. Measurements were taken with the help of UNC-15 probe [Tables 3 and 4]. All measurements were taken at the time of surgery and 2 months after surgery. Crown preparation was done for the abutment teeth in all patients so that temporary prosthesis can be given to the patient immediately after the augmentation procedure.

Figure 1

Preoperative photograph (facial view)

Figure 2

Preoperative photograph (palatal view)

Table 3

Percentage of vertical soft tissue augmentation

Table 4

Percentage of horizontal soft tissue augmentation

Surgical procedure

After adequate anesthesia, an exaggerated curvilinear beveled incision was given on the buccal aspect of the recipient site [Figure 3]. Abbreviated vertical releasing incisions were made on the palate at the mesial and distal aspect of the recipient site. Horizontal incision was made connecting the vertical incisions and then the buccal flap was elevated by blunt dissection [Figure 3]. Donor site was prepared by extending the incision on the distal aspect of the recipient bed palatally. This incision was given parallel to the gingival margin of the teeth and 2 mm apical to the marginal gingival up to the distal aspect of the second premolar. Using the single incision technique, sub-epithelial dissection was made from the distal aspect of second premolar and carried anteriorly toward the distal aspect of the canine. A vertical incision was then made at the distal aspect of the sub-epithelial dissection. Subepithelial connective tissue layer was elevated beginning from second premolar area toward the anterior extent of the dissection by blunt dissection. A second incision was then initiated under tension internally at the apical extent of the previous vertical incision and extended horizontally anterior to the distal aspect of the canine. Tension releasing cutback incisions was extended into the base of the pedicle flap for flap rotation [Figure 4]. Flap is rotated into the recipient site [Figure 5] and rigidly immobilized with sutures placed apically and laterally [Figure 6]. Donor and recipient sites were sutured primarily with Ethicon absorbable mersutures (Chromic NW 4237; 3-0, Johnson & Johnson Ltd., Plot no.58-B, Jharmajri, Baddi, HP-173205, India) using an interrupted suture technique [Figures 7 and 8] and gentle pressure was applied with moistened gauze for 10 min.

Figure 3

Curvilinear incision placed and full thickness flap is reflected

Figure 4

Vascularized interpositional periosteal connective tissue flap pedicled from palate

Figure 5

Pedicled flap positioned on defect site

Figure 6

Vascularized interpositional periosteal connective tissue flap sutured

Figure 7

Buccal flap sutured over vascularized interpositional periosteal connective tissue

Figure 8

Palatal view of sutured flap

Postoperative instructions

The patients were given post-operative instructions and medications. Amoxicillin (500 mg 3 times a day for 5 days) and ibuprofen (3 times a day for 3 days) were prescribed. Continuous rinsing with 0.12% chlorhexidine solution twice daily for 3 weeks was prescribed. The patient was advised to refrain from retracting the lips and cheeks and to avoid brushing or flossing in the grafted area for 6 weeks.

The sutures remain in situ for 2 weeks. Before the provisional FPD was cemented, the pontic must be shaped and allowed to come into contact with the soft tissue only slightly. After 2 months, the patient was referred to Department of Prosthodontics for rehabilitation with fabrication of the prosthesis. The postoperative follow-up was repeated every 3 months for the 1-year. At every follow-up visit, professional phase 1 therapy including scaling and oral hygiene instructions was performed.

Statistical analysis

Means and standard deviations (SDs) were calculated from data obtained within the group. Paired t-test was performed for all patients for statistical analysis.

RESULTS

Postoperative bleeding was not observed in any of the patients after the donor site was sutured. The augmented connective tissue showed little shrinkage after approximately 2-3 months. Postoperative morbidity was similar to that after removing a free subepithelial connective tissue graft from the palate. Two months postsurgery, the soft tissues have healed completely and adequately [Figures 9 and 10]. The patients were found to be satisfied with the final restoration based on readings over a visual analog scale at 2 months and 12 months follow up period. [Figure 11 and 12].

Figure 9

Postoperative photograph at 2 months (facial view)

Figure 10

Postoperative photograph at 2 months (palatal view)

Figure 11

Fixed partial denture placed after 2 months

Figure 12

Postoperative photograph at 12 months

Table 5 presents the data relating to changes in clinical parameters among the groups. Highly significant (HS) changes were found in the height and width of the residual ridge. The mean ± SD for height of the defect was 4.60 ± 1.07 mm at the baseline which decreases to 0.70 ± 0.67 mm after the procedure resulting in 3.90 ± 0.74 mm., that is, 85% decrease of the defect (P < 0.001, HS). Similarly, the mean ± SD for width of the defect was 3.5 ± 0.85 mm before the augmentation procedure, which decreased to 0.80 ± 0.79 mm resulting in 2.70 ± 0.95 mm., that is, 77% decrease of the defect (P < 0.001, HS).

Table 5

Measurements of ridge before and after the procedure

DISCUSSION

Abrams et al.[2] showed 91% prevalence of the anterior ridge deformity in the mandibular and maxillary arches of partially edentulous patients. Class III defects showed prevalence of about 55.8%, followed by Class I defect, which was 32.8% and Class II defects, which were 2.9%. As Class III defects are more prevalent, they were taken into consideration for this study.

The cases presented refer to the treatment of a Class III alveolar crest defect in maxillary anterior region with VIP-CT flap. It has been stated that up to three-tooth defects of moderate severity can be corrected successfully by less complicated soft tissue augmentation procedure.[4] Most of the earlier techniques have the drawback of less gain in volume because of limited size of the graft that can be used. Large onlay grafts have chances of necrosis due to lack of sufficient blood supply.[4516]

Unlike this, in VIP-CT flap technique, the amount of tissue gain is more and the pedicled blood supply is derived from the connective tissue periosteal plexus within the flap that provides the biological basis for predictable coverage.[17]

Vascularized interpositional connective tissue grafts for ridge augmentation preserve the color match and characteristics of overlying mucosa resulting in a better esthetic blend in a potentially highly visible area. In contrast, onlay grafts retain their palatal mucosal characteristics, which may compromise tissue esthetics.[4516]

In this technique, the flap is covered with buccal flap resulting in maintaining natural coloration and texture thereby reducing the need for secondary procedures. The donor site is near the surgical field and has minor morbidity. The surgical technique is simple, quick, and predictable. The flap has a random pattern blood supply, can have a width/length ratio of up to 1/5[12] and is used for minor ridge reconstruction of maxillary esthetic regions and simultaneously reconstructs both hard and soft tissue defects.[1318]

Because the donor site remains primarily covered, the risk-to benefit ratio is better than with other harvesting techniques. The use of a palatal protective template can increase safety, and the potential risk of postoperative bleeding is minimized.[19]

The cost of the procedure is low, does not interfere with the possibility of implant therapy in the future and can be repeated to improve the result.

Overall, it is accepted that ridges that have been augmented with soft tissues undergo shrinkage over the first 6 weeks postoperative. From 2 months postsurgery, the ridge dimensions remain stable. In this study, complete healing of the sites occurs within a month. Although, long-term follow-up of the cases has not been done but many authors report stability over periods that range from 2 to 10 years. The use of VIP-CT flap seems to be a good substitute for currently available techniques of soft tissue ridge augmentation.

However, there are few limitations of the procedure. There is difficulty to correct additional mucogingival problems in the same surgical act, e.g. a shallow vestibule or a mucogingival line that is too near the crest of the alveolar ridge. No controlled studies have been performed to examine the long-term stability of localized ridge augmentation with soft tissues. Before cementing provisional FPD, the pontic should be properly shaped and allowed to be slightly in contact with the soft tissue, any defect in the ridge may lead to esthetic and functional problems.

The soft tissue ridge augmentation technique poses many difficulties one of which is a gain in the volume of the defect that depends on the size of the graft. A larger defect cannot be treated with a full thickness onlay graft because these grafts can be harvested to a limit. A larger graft is more prone to necrosis and also leads to more of an injury to the donor site.[20] Therefore, the present study favors less injury to the donor site and a good amount of graft size that may help in proper gingival contours adapted to the shape of the pontic.

CONCLUSION

A significant gain in tissue volume has been achieved in the apicocoronal and buccolingual directions. Based on the result of the study, the technique would be effective in treating Class I, II, and III deformities of the alveolar crest that involve one or more missing teeth. However, further studies are necessary to confirm these findings in a larger series of patients.