29 March 2023

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How much does gingival thickness affect post-implant bone remodeling?

Lara Figini

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The stability of the marginal bone and soft tissue around dental implants has been established as the main feature to ensure the health of the implant.

The healthy condition of the soft tissue supports peri-implant bone stability and allows for a greater success of the implant and related prosthetic components. The peri-implant soft tissue structure establishes a biological barrier against bacteria and acts as a protective factor against peri-implant diseases.

One of the criteria to define the potential presence of peri-implant pathology is the evidence of progressive bone loss. However, late marginal bone loss (MBL) must be distinguished from early bone remodeling.

Early remodeling is initial bone remodeling with a variable non-infectious process occurring within the first year after implant placement. It has a multifactorial etiology and could be influenced by many local factors, such as those related to surgery and post-surgery. However, it should be emphasized that an infection process can occur even at an early stage.

Late bone loss, on the other hand, can be related to an infectious process called peri-implantitis which requires a diagnosis by evaluating the clinical and radiological parameters.

Several literature studies have now suggested that gingival thickness can interfere with the bone remodeling in cases of implantology, especially in the early post-surgical period.

Materials and methods

In a systematic review published in Clinical Oral Implants Research in February 2023, the authors evaluated the influence of soft tissue thickness on initial bone remodeling after implant placement. About this work Prof. Massimo Gagliani in his Monday Agora.

The literature search was conducted by two independent reviewers via electronic databases up to May 2022. Human clinical trials (CCTs), randomized controlled trials (RCTs), and controlled trials were included. The risk of bias was assessed using the Cochrane Collaboration tool. 

Meta-analysis and trial sequential analysis (TSA) of selected articles were performed. The primary outcome was a marginal bone loss.

Results

After the initial screening, 6 studies were included in the final analysis, with a total of 354 implants and a follow-up of 10 to 14 months. 194 implants were placed with a soft tissue thickness ≥2 mm and 160 with a soft tissue thickness <2 mm before implant placement.

The included studies showed a high level of heterogeneity (I2 >50%). The meta-analysis showed a statistically significant difference between the two groups (0.54; p = 0.027), and the TSA analysis confirmed the results, despite the limited number of dental implants considered.

The results of this review showed that bone remodeling is more significant when the initial thickness of the keratinized soft tissues is less than two millimeters.

Further analysis showed that age and follow-up were not statistically significant factors influencing bone loss (p = 0.22 and p = 0.16, respectively).

Conclusions

From the data of this review, which need to be confirmed in other similar studies and reviews, it can be concluded that initial soft tissue thickness appears to influence marginal bone loss after a short follow-up period.