The I-incision: a lever for papillary aesthetics?

The success of implant treatment is no longer limited to osseointegration; the stability and aesthetics of peri-implant soft tissues, particularly the preservation of papillae in the anterior zone, are now clinical imperatives. The appearance of "black triangles", resulting from inadequate gingival architecture, remains a frequent complication influenced by bone dimensions and the choice of surgical technique during functional loading.

This randomised study, conducted on 60 implant sites in 30 patients followed for 180 days, aims to compare the impact of two incision designs during second-stage surgery: the classic mid-crestal incision and the I-shaped incision. The objective is to precisely evaluate which of these approaches promotes better tissue maturation and optimal papillary fill.

The authors test the hypothesis that the I-incision, by better preserving local vascularisation, would offer superior aesthetic results compared to the traditional mid-crestal technique for the reconstruction of interproximal tissues.

Clinical trial methodology

This randomised clinical trial was conducted on 60 implant sites in 30 patients (11 men and 19 women), aged 25 to 65 years. The study aimed to compare the influence of two incision techniques during second-stage surgery on the maturation of peri-implant tissues.

The sites were divided into two distinct groups:

• Group 1: Use of a conventional mid-crestal incision.
• Group 2: Use of an I-shaped incision.

The experimental protocol included clinical follow-up at three key time points: at baseline, at 90 days and at 180 days. The researchers collected the following data for each site:

• Clinical indices: Modified plaque index (mPI) and modified gingival index (mGI).
• Papilla evaluation: Papilla Index Score (PIS).
• Dimensional measurements: Vertical distance between the bone crest and the contact point (D1), horizontal inter-implant or inter-dental distance (D2) and papilla height (D3).

Statistical analysis was performed using ANOVA tests, the unpaired t-test and the Z-test, with a significance level set at p < 0.05.

Results: Superiority of the I-incision on papillary fill

Analysis of the data collected from the 60 implant sites shows a favourable clinical progression in both groups, but with marked disparities regarding the final aesthetics of the papilla.

Evolution of clinical and dimensional indices

Both groups showed statistically significant improvements (p < 0.05) over the 180-day follow-up period for the following parameters:

• Modified Plaque Index (mPI) and Modified Gingival Index (mGI).
• Measurements of the vertical distance (D1: from the bone crest to the contact point) and papillary height (D3).

Although both techniques allow tissue healing, the extent of dimensional changes and the quality of mucosal maturation differ depending on the incision design.

Comparison of papillary formation (PIS)

The papilla index score (PIS) at 180 days reveals a major difference between the two surgical protocols:

At the end of the study, more than half of the Group 2 sites (53.3%) achieved complete papillary fill (PIS 3), whereas none of the Group 1 sites succeeded in completely filling the embrasure space (0%).

Correlations and qualitative observations

The results highlight a direct correlation between the presence of the papilla and the vertical (D1) and horizontal (D2, inter-implant or tooth-implant distance) dimensions. The analysis suggests that the I-incision better preserves the vascularisation of the flap, which promotes a greater tissue volume gain compared to the conventional mid-crestal approach. This vascular preservation appears to be the determining factor for achieving an optimal aesthetic result and the prevention of "black triangles".

Clinical analysis and impact on peri-implant aesthetics

The finding of this study is unequivocal: the I-incision offers a major advantage in the aesthetic zone. The fact that more than half of the patients (53.3%) achieve a PIS 3 score at six months highlights this technique's ability to preserve local vascularisation and optimally reposition tissues. In comparison, the systematic failure of the mid-crestal incision to restore a complete papilla (0% PIS 3) raises questions about its relevance in areas of high visual demand.

The data show that success, however, depends on respecting the biological dimensions (D1 and D2). The study suggests that the I-incision not only exposes the implant, but acts as a true reconstructive procedure. Although the sample of 30 patients is modest and the follow-up limited to 180 days, the strength of the statistical correlation validates the clinical adoption of this protocol to limit the appearance of black triangles.

Summary of results

The study conducted on 60 implant sites demonstrates a clear clinical superiority of the I-shaped incision over the mid-crestal technique: at 180 days, 53.3% of the sites in the "I-shaped" group achieved complete papillary fill (PIS score 3), compared to 0% for the control group. These results are explained by better preservation of vascularisation and peri-implant tissue volume during second-stage surgery.

In practical terms, for the practitioner:

• Adopt the I-incision for your stage 2 uncovery, specifically in the aesthetic zone, to maximise your chances of eliminating black triangles.
• Preserve vascularisation: favour this surgical design which better respects the local blood supply than the classic crestal incision, thus promoting papillary healing.
• Anticipate the fill potential: the study confirms that despite the chosen technique, the final presence of the papilla remains correlated with the vertical (crest-contact point) and horizontal (inter-implant) distances.

Technical glossary of the study

Osseointegration: Direct structural and functional connection between living bone and the surface of an implant subjected to functional load, a prerequisite for the long-term success of implant treatment.

I-shaped incision: Specific incision design used during second-stage surgery, designed to preserve local vascularisation and optimise tissue repositioning for papillary fill.

Mid-crestal incision: Conventional technique consisting of a linear incision at the top of the alveolar ridge to expose the implant, serving here as the control group.

Papillary Index Score (PIS): Clinical scoring system used to assess the degree of interproximal space fill by the papilla, with a score of 3 corresponding to complete fill.

Black triangles: Aesthetic deficits resulting from insufficient papillary volume between two implants or between an implant and a natural tooth, creating a dark space beneath the contact point.

Tissue biotype: Morphological characteristics (thickness and width) of the gingiva and alveolar bone, identified as a determining factor in the formation and stability of the papilla.

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