Evaluation of free connective tissue graft and collagen matrix clinical effectiveness to increase soft tissue thickness around dental implants

Relevance. Implant-supported prostheses are currently one of the most popular rehabilitation methods in partially or fully edentulous patients. Peri-implant soft tissue thickness is one of the principal determinants to achieve an aesthetic result and prevent the development of mucositis and peri-implantitis.

Material and methods. The study included 30 partially edentulous patients with a lack of soft tissue thickness in the planned surgery site. 15 patients underwent augmentation using a collagen matrix (group 1) and 15 patients – with a free connective tissue graft (group 2). The primary endpoint was the assessment of soft tissue thickness gain three months after the surgery. The secondary endpoints were the thickness assessment of keratinized attached gingiva (three months after the surgery), swelling and pain severity (on the 1^st, 3^rd, 5^th, 7^th day, 1 and 3 months after the surgery) and quality of life evaluation (OHIP-14) (before the surgery, seven days and three months after the surgery).

Results. The soft tissues thickness gain was 1.181 ± 0.11 mm in group 1, 1.55 ± 0.11 mm – in group 2. The surgery took 8.4 minutes less (from 3.737 to 13.06) in group 1 than in group 2. The swelling assessment on the next day after surgery showed that the mean value was 2.73 ± 0.3 in group 1, 1.87 ± 0.74 – in group 2 (р = 0.0139). There were no statistically significant differences in the change in the width of the keratinized attached gingiva, pain syndrome and changes in patients' quality of life (p > 0.05)

Conclusion. Collagen matrix, like a free connective tissue graft, is an effective way to increase the soft tissue thickness around dental implants.

1. Chackartchi T, Romanos GE, Sculean A. Soft tissue-related complications and management around dental implants. Periodontology 2000. 2019;81(1):124-138. doi: 10.1111/prd.12287

2. Tarasenko SV, Zagorskij SV. Review of Methodology and Materials Using for Building of Gum Soft Tissues. Journal of Clinical Practice. 2019;10(1):57-62 (In Russ.). doi: 10.17816/clinpract10157-62

3. Thoma DS, Gasser TJW, Jung RE, Hämmerle CHF. Randomized controlled clinical trial comparing implant sites augmented with a volume-stable collagen matrix or an autogenous connective tissue graft: 3-year data after insertion of reconstructions. Journal of Clinical Periodontology. 2020;47(5):630-639. doi: 10.1111/jcpe.13271

4. Roccuzzo M, Grasso G, Dalmasso P. Keratinized mucosa around implants in partially edentulous posterior mandible: 10-year results of a prospective comparative study. Clinical Oral Implants Research. 2016;27:491-496. doi: 10.1111/clr.12563

5. Agrawal H, Kumar R, Kanteshwari IK, Jaiswal G, Marothiya S, Jasuja A, et al. Soft & Hard Tissue Assessment around Immediate & Delayed Implants: A Clinico-Radiographical Study. Mymensingh Medical Journal: MMJ. 2020;29(3):691-700. Available from: https://pubmed.ncbi.nlm.nih.gov/32844813/

6. Giannobile WV, Jung RE, Schwarz F, Groups of the 2nd Osteology Foundation Consensus Meeting. Evidence-based knowledge on the aesthetics and maintenance of peri-implant soft tissues: Osteology Foundation Consensus Report Part 1-Effects of soft tissue augmentation procedures on the maintenance of periimplant soft tissue health. Clinical Oral Implants Research. 2018;29 Suppl 15:7-10. doi: 10.1111/clr.13110

7. De Angelis P, De Angelis S, Passarelli PC, Liguori MG, Pompa G, Papi P, et al. Clinical comparison of a xenogeneic collagen matrix versus subepithelial autogenous connective tissue graft for augmentation of soft tissue around implants. International Journal of Oral and Maxillofacial Surgery. 2021;50(7):956-963. doi: 10.1016/j.ijom.2020.11.014

8. Puzio M, Błaszczyszyn A, Hadzik J, Dominiak M. Ultrasound assessment of soft tissue augmentation around implants in the aesthetic zone using a connective tissue graft and xenogeneic collagen matrix – 1-year randomised follow-up. Annals of Anatomy – Anatomischer Anzeiger. 2018;217:129-141. doi: 10.1016/j.aanat.2017.11.003

9. Tavelli L, Barootchi S, Avila-Ortiz G, Urban IA, Giannobile WV, Wang HL. Peri-implant soft tissue phenotype modification and its impact on peri-implant health: A systematic review and network meta-analysis. Journal of periodontology. 2021;92(1):21-44. doi: 10.1002/JPER.19-0716

10. Gargallo-Albiol J, Barootchi S, Tavelli L, Wang HL. Efficacy of Xenogeneic Collagen Matrix to Augment Peri-Implant Soft Tissue Thickness Compared to Autogenous Connective Tissue Graft: A Systematic Review and Meta-Analysis. International Journal of Oral and Maxillofacial Surgery. 2019;34(5):1059-1069. doi: 10.11607/jomi.7497

11. Linkevicius T, Vindasiute E, Puisys A, Linkeviciene L, MaslovaN, Puriene A. The influence of the cementation margin position on the amount of undetected cement. A prospective clinical study. Clinical Oral Implants Research. 2013;24 (1):71-76. doi: 10.1111/j.1600-0501.2012.02453.x

12. Puisys A, Linkevicius T. The influence of mucosal tissue thickening on crestal bone stability around bone-level implants. A prospective controlled clinical trial. Clinical Oral Implants Research. 2015;26:123-129. doi: 10.1111/clr.12301

13. Cairo F, Barbato L, Tonelli P, Batalocco G, Pagavino G, Nieri M. Xenogeneic collagen matrix versus connective tissue graft for buccal soft tissue augmentation at implant site. A randomized, controlled clinical trial. Journal of Clinical Periodontology. 2017;44(7):769-776. doi: 10.1111/jcpe.12750

14. Naenni N, Walter P, Hämmerle CHF, Jung RE, Thoma DS. Augmentation of soft tissue volume at pontic sites: a comparison between a cross-linked and a non-cross-linked collagen matrix. Clinical Oral Investigations. 2021;25(3):1535-1545. doi: 10.1007/s00784-020-03461-8

15. Sanz-Martín I, Rojo E, Maldonado E, Stroppa G, Nart J, Sanz M. Structural and histological differences between connective tissue grafts harvested from the lateral palatal mucosa or from the tuberosity area. Clinical Oral Investigations. 2019;23(2):957-964. doi: 10.1007/s00784-018-2516-9

16. Thoma DS, Zeltner M, Hilbe M, Hämmerle CHF, Hüsler J, Jung RE. Randomized controlled clinical study evaluating effectiveness and safety of a volume-stable collagen matrix compared to autogenous connective tissue grafts for soft tissue augmentation at implant sites. Journal of Clinical Periodontology. 2016;43(10):874-885. doi: 10.1111/jcpe.12588