Part 1 - Dental Implant Soft Tissue Management
“A weak seal between the implant surface and peri-implant tissue is often the source of bacterial invasion and, consequently, inflammation. As such, transmucosal healing and the stability of the peri-implant mucosa can have an impact on the long-term survival of dental implants”
We often talk about optimising the soft tissue around dental implants. It is widely recognised as an important part of implant treatment and clinicians are constantly advancing their capabilities and experience in the field in order to achieve ever-better outcomes for their patients. Understanding the role that it plays in healing and aesthetics, developing the skills and confidence to properly assess and manage the soft tissue, and utilising the most appropriate materials and solutions will all help to elevate treatment results.
Healing and longevity
Among the key functions of the soft tissue is its role in protecting the implant from bacterial infiltration. In fact, the soft tissue is often credited as the main reason why implant failure due to infection is so low across the industry, making them the most successful biomaterial implants in the human body. i It does this by creating a seal at the coronal portion of the implant, forming a barrier to bacteria. Immediately following implant placement, a blood clot forms on the implant-mucosa interface, containing neutrophils, which aid attachment to the implant within a few days – where bacteria is not present. The attachment process usually takes around 8 weeks to form a seal. ii
A weak seal between the implant surface and peri-implant tissue is often the source of bacterial invasion and, consequently, inflammation.iii As such, transmucosal healing and the stability of the peri-implant mucosa can have an impact on the long-term survival of dental implants.
Similar, but not the same
To optimise this interface, it is important to note the differences between the soft tissue structures around natural teeth and those surrounding implants. Teeth are one of only a few organs in the human body that are located across the skin barrier, meaning they and their supporting tissues have a rather unique biology. As teeth pierce the gingiva, the gaps are sealed by an epithelial and connective tissues. The sealing mechanisms around implants are similar, but not the same. Firstly, the gingival fibres are located in different directions; around implants they are parallel to the surface, while around natural teeth they attach vertically. Secondly, while natural teeth are directly attached to connective tissue, fibroblasts and collagen fibres maintain attachment to the implant surface. In addition, epithelium attachment forms only in the lower section of the peri-implant epithelium, compared to much wider distribution of attachments across the junctional epithelium around a natural tooth.iv Soft tissue attachment to a dental implant is therefore weaker than around a natural tooth.
Soft tissue assessment
Soft tissues deficiencies can occur for a number of reasons, often due to resorption of the bony ridge after tooth loss. Periodontitis is another common culprit, causing gingival recession and pocket formation.v Tooth loss (or extraction) can also lead to resorption of the surrounding bone and keratinised mucosa during implant placement.
It is important to accurately assess and understand the condition of the soft tissue before implant surgery is conducted. This is an integral step in the treatment planning process and involves evaluation of both the quantity and quality of soft tissue present, including horizontal and vertical, height and thickness. For example, there is evidence to show that implants placed in sites with thicker periodontal tissues demonstrate less radiographic marginal bone loss in the short-term.vi It has also been postulated that a greater height and thickness of soft tissue may reduce incidence of inflammation and other future complications.vii
When assessing the soft tissue, consideration should also be given to the soft tissue quality and quantity in terms of aesthetics. Gingival volume can have a significant influence over the aesthetic outcome, as sufficient tissue is needed to close over the implant without tension.
Another consideration is the position of the implant(s). For example, a minimum of 6mm in mesiodistal extension is recommended to provide a distance of 1.5mm from adjacent teeth, as well as at least 6mm muccolingual bone volume to allow 1.5mm on the facial/buccal aspect and at least 0.5mm on the palatal aspect.viii This demonstrates the 3-dimensional approach needed for successful planning of implant position, which facilitates effective soft tissue management and improved aesthetic results.
To further encourage a high standard of aesthetics and durable results, the biocompatibility of materials used during surgical and restorative treatment should be deliberated. Biomaterials are developed specifically to optimise the interface between a foreign body and natural tissues. In implantology, titanium and its alloys are used for dental implants as they feature a low electrical conductivity that encourages the formation of an oxide layer that protects the material from corrosion.ix Zirconia has also become popular for abutments, given that studies suggest increased blood flow in tissues surrounding the material – even similar to that around natural teeth.x
Optimising soft tissue
Having established the importance of soft tissue around implants, we next need to understand the options available to improve its condition. In the next article of the series, we will look at the different periodontal procedures available.
Ren X, van der Mei HC, Ren Ym Busscher HJ. Keratinocytes protect soft-tissue integration of dental implant materials against bacterial challenges in a 3D-tissue infection model. Acta Biomaterialia. 2019. 96; 237-246 https://doi.org/10.1016/j.actbio.2019.07.015
Wang Y, Zhang Y, Miron RJ. Health, maintenance and recovery of soft tissue around implants. Clinical Implant Dentistry and Related Research. 2015. 18(3). DOI:10.1111/cid.12343
Atsuta I, Ayukawa Y, Kondo R, Oshiro W, Matsuura Y, Furuhashi A, Tsukiyama Y, Koyano K. Soft tissue sealing around dental implants based on histological interpretation. Journal of Prosthodontic Research. January 2016. 60 (1);3-11. https://doi.org/10.1016/j.jpor.2015.07.001
Kim JJ, Lee JH, Kim JC, Lee JB, Yeo IL. Biological Responses to the Transitional Area of Dental Implants: Material- and Structure-Dependent Responses of Peri-Implant Tissue to Abutments. Materials (Basel). 2019;13(1):72. Published 2019 Dec 22. doi:10.3390/ma13010072
Hämmerle CHF, Tarnow D. The etiology of hard- and soft-tissue deficiencies at dental implants: A narrative review. Journal of Periodontology. June 2018; 89(S1); S291-S303. doi.org/10.1002/JPER.16-0810
Suárez-Lopez del Amo F, Lin GH, Monje A, Galindo-Moreno P, Wang HL. Influence of soft tissue thickness on peri-implant marginal bone loss: A systematic review and meta-analysis. Journal of Periodontology. June 20216. 87(6);690-699 doi.org/10.1902/jop.2016.150571
Lin GH, Madi IM. Soft-Tissue Conditions Around Dental Implants: A Literature Review. Implant Dent. 2019 Apr;28(2):138-143. doi: 10.1097/ID.0000000000000871. PMID: 30913109.
FOR. Treatment Guidelines. https://www.for.org/en/treat/treatment-guidelines/single-tooth/treatment-options/treatment-options-esthetic-zone/implant-position-esthetic-zone [Accessed May 2021]
Sidambe AT. Biocompatibility of Advanced Manufactured Titanium Implants-A Review. Materials (Basel). 2014;7(12):8168-8188. Published 2014 Dec 19. doi:10.3390/ma7128168
Kajiwara N, Masaki C, Mukaibo T, Kondo Y, Nakamoto T, Hosokawa R. Soft tissue biological response to zirconia and metal implant abutments compared with natural tooth: microcirculation monitoring as a novel bioindicator. Implant Dent. 2015 Feb;24(1):37-41. doi: 10.1097/ID.0000000000000167. PMID: 25290282.