Applied Research Of Attached Gingiva Reconstruction In Implant-Supported Dental Prosthesis

Objective:In this study, apically positioned flap was modified to reconstruct attached gingiva around implants at the time of secondary operation. The purpose of this study was to observe the effect of attached gingiva reconstruction in a short term and analyze its influence on implant restoration. In addition, this study was also expected to provide experimental bases and a new approach for soft tissue management in patients insufficient of attached gingiva around implants.Methods:1. Subjects were selected according selection criteria from patients who had accepted implant treatment in Oral Implantology Centre, Shandong University Hospital of Stomatology. A total of10implants in8eligible patients were finally identified for attached gingiva reconstruction at the time of secondary operation. Regarding gender, there were2male and6female patients. The mean age was40.6years ranging from20to61.The implant system used was Ankylos.2. Preoperative examination of the buccal keratinized gingiva, vestibular groove and frenulum attachment was performed. Effective keratinized gingiva width was recorded.3. Trapezoidal incision with preservation of papilla was used in the buccal side of the implant site under local anesthesia. Crest incision should be within keratinized gingiva and located at lingual (palatal) side a little bit. Periosteum should not be cut through by mesial and distal additional incisions which crossed mucogingival junction and could also extend to the bottom of vestibular groove according to actual needs. Split-thickness flap was then carefully elevated by using sharp blade with partial connective tissue and underlying periosteum well preserved. Muscle fibers were peeled off. Mucosa flap was moved towards the vestibular groove and sutured to the periosteum with absorbable suture so that the free end of keratinized gingiva was apically positioned beneath adjacent normal mucogingival junction. In the meantime, the cover screw was replaced by Ankylos healing abutment of corresponding gingival height. Subsequently, flap was pressed gently with saline gauze to make the extravasated blood flow away. The exposed periosteal area was protected by covering Voco periodontal pack.4. Impression was made after2weeks and superstructure was restored by porcelain crown after4weeks. Subjects were recalled6months after restoration. At the latter two time points, effective keratinized gingiva width was recorded, state of reconstructed keratinized gingiva was evaluated, and position of mucogingival junction was observed. At6months after restoration, implant was examined clinically and radiographically. Clinical examinations included modified plaque index, probing depth, bleeding index and percentage of bleeding on probing.5. Experimental data were statistically analyzed by SPSS18.0software.Results:1. The study consisted of10implants in8patients who finally accepted reconstruction surgery of attached gingiva around implants at the time of secondary operation. Gingiva healed well with good soft tissue cuff around all implants except one where inflammation still existed after2weeks. Normal keratinized gingiva formed and mucogingival junction was in coordination with adjacent parts after4weeks.2. Comparison of effective keratinized gingiva width was analyzed using Wilcoxon signed rank test. The mean width was0.19±0.45mm and2.60±0.47mm before and4weeks after the surgery separately. A statistically significant difference was shown(p <0.05) with an average increase of2.41mm. The mean width was2.64±0.53mm at6months after restoration and was also statistically significantly higher than the preoperative value (p<0.05). In contrast, a statistically significant difference was not shown compared with the value at4weeks after the surgery (p>0.05).The newly formed keratinized gingiva remained stable after6months of function.3. Oral hygiene was generally good and all implants were stable in the subjects after6months of function. No obvious inflammation was detected in the newly formed keratinized gingiva which attached to the crown tightly. Clinical examinations showed a low modified plaque index of0.70±0.82, a mean probing depth of1.80±0.36mm with no deep pockets, and a mean bleeding index of0.73±0.64. In terms of bleeding on probing,23.3%of all sites showed positive outcome.Conclusion:1. By using a modified technique of apically positioned flap at the time of secondary operation, the width of keratinized gingiva around implants can be effectively augmented, attached gingiva can be reconstructed and mucogingival junction can return to normal position. Therefore, this technique is a good method for soft tissue management around implants.2. Under good oral hygiene, plaque control of implants is acceptable and the newly formed attached gingiva is capable of keeping healthy and stable in a short term. Long-term effects need to be confirmed by further studies.