Converting Thin to Thick Gingival Biotype: Surgical Options

The gingival biotype describes the thickness and the contour of the gingiva around a tooth or an implant, and it strongly influences the prognosis of every restorative and periodontal procedure. A thin, scalloped biotype is fragile: recession follows minimal trauma, the soft tissue shows through ...

# Converting Thin to Thick Gingival Biotype: Surgical Options

The gingival biotype describes the thickness and the contour of the gingiva around a tooth or an implant, and it strongly influences the prognosis of every restorative and periodontal procedure. A thin, scalloped biotype is fragile: recession follows minimal trauma, the soft tissue shows through dark restorations, and the tissue around a thin-scalloped implant responds poorly to inflammation. Converting a thin biotype to a thicker one is therefore a common and valuable goal. This article reviews the surgical options and when each is appropriate.

Recognizing the Thin Biotype

How the Biotype Is Assessed

The clinician identifies the biotype by a combination of signs and measurements. A periodontal probe passed through the sulcus reveals the outline through a thin margin, and this probe transparency is the practical office test. The morphology provides another clue, because a thin-scalloped biotype shows a pronounced scallop with slender papillae, while the thick-flat biotype has a flat, dense margin. The shape of the bone and the tooth also contribute.

The Clinical Consequences

A thin biotype carries a higher risk of gingival recession at every stage of treatment, from orthodontic movement to the placement of a restoration margin, and even routine brushing can strip the fragile margin. Around a crown preparation a thin margin is likely to recede, and around an implant the thin phenotype allows the gray of the abutment to show through and provides a smaller platform of soft tissue that can harbor inflammation. The conversion of the biotype is therefore pursued not only for appearance but also as a biological insurance for the tooth and the surrounding attachment.

The Surgical Options

Free Gingival Grafts and Apically Positioned Flaps

The classic way to thicken the gingiva in a non-esthetic zone is the free gingival graft, which adds a layer of keratinized tissue harvested from the palate. The graft is sutured over a bed prepared by an apically positioned flap, and the result is a dense band of keratinized mucosa that withstands inflammation and resists recession. The limitation is esthetic: the graft shows a different color and texture from the surrounding tissue, so the free gingival graft is reserved for areas where the appearance is secondary, such as in the posterior segments or at the base of the vestibule.

Subepithelial Connective Tissue Grafts

The subepithelial connective tissue graft is the workhorse of biotype conversion in the esthetic zone. A piece of connective tissue is harvested from the palate through a trapdoor or a single-incision technique, is placed beneath an intact gingival envelope or a split-thickness flap, and is covered so that no epithelium is exposed. The graft thickens the tissue at a depth where it cannot be seen, and the resulting gingiva is denser, more vascular, and more resistant to recession, all without the color mismatch of the free graft. The technique is ideal for the facial aspect of an anterior tooth and for thickening the peri-implant tissue around an implant before restoration.

Acellular Dermal Matrix and Xenograft Substitutes

Where palatal tissue is scarce, or where the patient wishes to avoid a second surgical site, acellular dermal matrix and porcine or bovine collagen matrices provide a substitute. These materials act as a scaffold that becomes incorporated and thickens the gingiva, and they eliminate the donor site morbidity, although their long-term gain is less predictable and the cost higher. The choice between an autogenous graft and a substitute depends on the amount of thickening required, the availability of palatal tissue, and the patient's wishes,.

Planning and Execution

Timing of the Conversion

The timing of a biotype conversion must respect the treatment sequence. Around a tooth, the graft is best placed before the final restorative margins are cut, so that the tissue can thicken and settle before the margin. Around an implant, the tissue can be thickened at the time of placement or at the second stage, before final impressions, and a free or connective tissue graft is often combined with a bone graft where both soft and hard tissue defects exist. Whatever the sequence, the tissue is allowed to mature for several months before the final restoration is delivered.

Essential Skills and Complications

A successful conversion depends on a stable, well-vascularized recipient bed and on precision in harvesting. The graft should be handled gently, kept moist, and adapted tightly, and the recipient envelope must be large enough to accept the thickness without stretching the overlying flap, since a thinned-out graft adds bulk, and a necrotic graft is lost. The complications are the usual ones of periodontal plastic surgery: swelling and pain at the donor site, bleeding, and partial graft loss. The esthetic outcome improves with attention to the marginal contour, and a graft placed too high creates a bulky margin, so the position and size are planned from the desired architecture.

Clinical Key Points

- The thin biotype is identified by probe visibility and a pronounced scallop.

- A thin biotype brings a higher risk of recession around teeth and implants.

- The subepithelial connective tissue graft is the preferred esthetic conversion.

- The free gingival graft thickens tissue where esthetics are secondary.

- Matrix substitutes avoid a donor site when only modest thickening is needed.

- Grafting is timed before final margins and before orthodontic completion.

- A well-vascularized bed and careful technique determine graft survival.

Conclusion

The conversion of a thin gingival biotype to a thick one is one of the most useful procedures in periodontal plastic surgery. By placing connective tissue beneath the margin, the clinician reduces the risk of recession, protects the emergence of a restoration, and improves the response of the peri-implant tissue. The subepithelial connective tissue graft remains the reference technique in the esthetic zone, with free grafts and matrix substitutes reserved for the appropriate situations, and a carefully planned conversion turns a fragile margin into a stable and durable one.

（内容由AI生成，仅供参考）