New research: understanding periodontal & peri-implant soft tissues better

Periodontal & peri-implant soft tissue phenotype:

Soft tissue phenotype plays a critical role around teeth and dental implants and its impact on periodontal and peri-implant health, aesthetics, and stability of the soft tissue margin has primarily been examined by assessing “individual” components

1. Periodontal soft tissue phenotype: keratinised tissue (KT) width and gingival thickness (GT)
2. Peri-implant soft tissue phenotype: KT width, mucosal thickness (MT), and supracrestal tissue height at implant sites

Understanding the soft tissue phenotype better: “Soft tissue seal”

It is plausible to hypothesize that individual components of the soft tissue phenotype could exhibit a “collective and synergistic” interaction.

One of the critical characteristics attributed to periodontal and peri-implant soft tissues is their capacity to form a stable and protective barrier—”a soft tissue seal”, which significantly contributes to tissue health, aesthetic outcomes, and the maintenance of soft tissue margin stability, irrespective of the underlying buccal bone levels.

The ideal periodontal/ peri-implant soft tissue phenotype should be stiff, and not loose (elastic), to form a “soft tissue seal”, which can remain stable and protect the tooth/implant from plaque-induced pathological conditions.

Peri‐implantitis sites, due to the inflammatory infiltrate, often show a movable (more elastic than stiff) peri‐implant soft tissue mid-facially.

Our limitations in understanding the soft tissue phenotype better: Static vs Dynamic

While the importance of mucosal thickness and keratinised tissue is well-recognised, understanding how these tissues behave dynamically was limited. In other words, traditional methods couldn't clearly show how soft tissues around implants respond to “real-life mechanical forces”—like chewing or brushing.

Coming to grafted sites, modern technologies that evaluated the outcomes of soft tissue augmentation at implant sites gave an accurate assessment of the peri-implant hard and soft tissue structures, but again, their evaluation was “static”.

Therefore, we needed a method to assess the soft tissue phenotype in a “dynamic” manner, so that we could understand the soft tissue behaviour when the peri-implant soft tissue is pushed and compressed, such as how it happens during chewing, brushing, accidental trauma, etc.

Here, the key property of soft tissues that we need to assess is “elasticity” (stiffness) of peri-implant soft tissues, which is the direct manifestation of its intrinsic composition and characteristics.

Our lack of knowledge about soft tissue elasticity under function made it challenging for clinicians to predict long-term stability or potential complications.

Using a novel technology in dentistry:

A recent study used a new technology— ultrasound strain elastography —as a non-invasive method to observe and measure the elasticity of peri-implant soft tissues in real-time and under compression.

Ultrasonographic elastography has been extensively used in the medical field. However, its application around teeth and dental implants is yet to be explored.

Elastography assesses tissue elasticity— the tendency of the soft tissue to resist deformation with an applied force, and it largely depends on the intrinsic characteristics and properties of the specific tissue.

The current study compared the elasticity of soft tissues around implants to natural teeth before and after connective tissue grafts (CTG).

Ultrasound elastography evaluated the elasticity of peri-implant soft tissues and demonstrated that elasticity differs significantly between natural teeth and implants and changes over time after tissue grafting procedures.

What did they find?

1. Elasticity differs among teeth and implant sites at the most coronal region of the soft tissue, with peri‐implant tissues showing overall higher stiffness.
2. After grafting procedures, the peri-implant soft tissues became progressively stiffer, with peak stiffness achieved at about 12 months.
3. Greater stiffness was associated with wider bands of keratinized tissue and increased mucosal thickness.
4. Differences in elasticity were noticeable depending on the surgical technique used. Connective tissue graft with coronally advanced flaps produced higher stiffness compared to the same done with a tunnelling procedure.

Clinical implications:

• Provides clinicians with a practical tool for evaluating soft tissue health and healing.
• The authors believe that ultrasound strain elastography can go beyond —KT width, adherent mucosa (AM) width, mucosal thickness, and supracrestal tissue height as individual soft tissue phenotype components —and evaluate their synergistic effects in a dynamic manner.
• Helps guide better surgical and treatment decisions, enhancing the predictability and longevity of implant treatments.
• Ultrasound elastography can effectively measure how peri-implant soft tissues react and heal after grafting procedures, providing a new, dynamic way to evaluate tissue health.
• Understanding these elasticity patterns helps clinicians choose better surgical approaches and improve long-term implant success.

This approach marks a significant step forward, giving dentists a practical way to improve outcomes and patient satisfaction through better-informed clinical decisions. In essence, this research opens the door to more precise, personalised dental implant treatments, ultimately leading to healthier, more predictable outcomes for patients.

Reference: Tavelli L, Barootchi S. Soft tissue elasticity at teeth and implant sites. A novel outcome measure of the soft tissue phenotype. J Periodontal Res. 2024 Dec;59(6):1130-1142. doi: 10.1111/jre.13296. Epub 2024 Jun 5. PMID: 38837789; PMCID: PMC11626689.

Research team: Lorenzo Tavelli and Shayan Barootchi, Department of Oral Medicine, Infection, and Immunity, Division of Periodontology, Harvard School of Dental Medicine, Boston, MA, USA.

 

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