Evaluation of Keratinized Tissue Augmentation Using Amnion/Chorion Allograft vs. Autogenous Connective Tissue in Implant Therapy: A Retrospective Study

Objectives: Successful implant therapy must also ensure the integration of the soft tissues around the crown/abutment emergence profile. The existing literature does not consistently agree on the necessity of a minimal amount of keratinized tissue (KT), though it appears advantageous for the long-term stability and aesthetics of implants. The purpose of this clinical retrospective study is to compare the effectiveness of amnion/chorion membrane and autogenous subepithelial connective tissue in increasing the keratinized mucosa and maintaining it over a 5-year follow-up. Methods: Twenty patients who had previously undergone implant surgery were included in the study. Ten patients had received the allograft (Group 1) and ten had received autogenous connective tissue (Group 2).An independent examiner retrospectively analyzed the patient records at 7, 15, and 60 days, and five years post-procedure. Data from these observations were collected and analyzed using SPSS Statistics, version 25. Descriptive statistical analysis was conducted. Results: All patients exhibited an increase in KT. For Group 1, the mean KT width measurements were 1.27 ± 0.46 mm at the initial evaluation, increasing to 2.00 ± 0.38 mm, 2.80 ± 0.78 mm, 3.27 ± 0.80 mm, and 3.01 ± 0.68 mm at 7, 15, and 60 days post-surgery (with prosthesis delivery on day 60), and five years after prosthetic rehabilitation, respectively. Conclusions: Within the limitations of this retrospective clinical study, both amnion/chorion and connective tissue show significant potential for KT expansion when used in conjunction with implant surgery. Considering the minimally invasive approach, focusing future research on the use of allografts or xenografts appears justified. Clinical Relevance: the use of allografts , due their low morbidity, and acceptable results should be considered as a viable option for soft tissues augmentations.