Ridge Expansion: The Bruschi-Scipioni Technique

An implant needs bone. If bone is scarce, you can add it, or you can displace it. Adding costs more time, more money, more pain. Displacing it — when possible — is almost always the better choice.

This is the essence of ridge expansion.

The technical name is ERE: Edentulous Ridge Expansion. The historical name is the Bruschi-Scipioni technique, after the two Italian clinicians who codified it in 1994 in a now classic paper, published in the International Journal of Periodontics and Restorative Dentistry.¹

In this article I bring together, once and for all, what it is, when it can be done, how it is done, what we know from the evidence, and where the limit lies beyond which one must not go.

What it is

Ridge expansion is a surgical technique that widens a thin alveolar ridge to allow the placement of a dental implant.

Two principles define it.

The first: bone is not added, it is displaced. The buccal cortical plate is separated from the lingual or palatal cortical plate by a controlled cut, and pushed laterally. In the centre remains a medullary space that fills with blood clot and regenerates on its own, by bonebending — as we call it — not by grafting.

The second: the implant, when possible, is placed in the same session. The implant itself becomes the spacer that maintains the expansion. There is no waiting time, no second surgery.

Hence the name I use on the blog: bonebending. Bending the bone, not adding to it. It is the general philosophy; ridge expansion is its progenitor.

Authorship of the technique

The literature attributes the modern ERE to two Italian authors: Agostino Scipioni and Giovanni Battista Bruschi. The seminal paper is from 1994.¹ It is a prospective case series over five years: 329 implants on 170 expanded ridges, with survival rates and healing patterns that for the era were surprising.

My father is one of the two authors. I worked alongside him for years, and on this technique I have built much of my clinical practice and scientific output.² ³

It is not a matter of family, it is a matter of method: the expansion was written with rigour, and with rigour it must be told.

Indications

Not all thin ridges can be expanded. The true indications are three.

Starting thickness. It works well with ridges between 2 and 4 millimetres thick. Below 2 millimetres the buccal cortical plate risks fracture; above 4 millimetres, usually, the implant can be placed without expansion.

Two cortical plates and a medullary core. The classic anatomy of alveolar bone — buccal cortex, cancellous medulla, lingual or palatal cortex — must be recognisable. Without expandable medulla, there is no expansion: there is only a fracture to contain.

Sufficient residual height. Expansion works on width, not height. If height is lacking, something else is needed: sinus lift, vertical GBR, or decline.

The anterior and premolar maxilla is the territory of election. The posterior mandible, on the other hand, is the terrain of “you can, but with a different instrument and different nerves”.

Contraindications

Ridges too thin (< 2 mm). Knife-edge ridges without medullary bone. Severe combined atrophies. Patients with uncompensated bone healing disorders — bisphosphonates in active therapy, recent radiotherapy, uncontrolled diabetes.

And then a non-clinical contraindication: the inexperienced operator. Expansion is a sensitive technique. A splitting error is paid for with a fracture. An angulation error is paid for with an implant to remove. Those who do it well, do it with the right cases and a trained hand.

Surgical technique

I summarise in five steps. The details live in the individual in-depth articles, found at the end.

Flap. Partial thickness, preserving the periosteum (or better, a quota of connective tissue) on the buccal cortex. The periosteum is the vascularisation of the displaced bone; if you lose it, you lose the expansion.⁴

Cortical osteotomy. A cut along the ridge crest, plus two vertical release cuts (if necessary). Diamond disc in the mandible, chisels or ultrasonic osteotomes in the maxilla. Depth is controlled: only the outer cortex is cut.

Expansion. With expanders of increasing diameter the cancellous component is widened, and with it the ridge. Expansion is slow, gradual, elastic. One does not force.

Implant placement. The implant is inserted into the newly formed bone socket. In most cases loading will be deferred; in selected cases, immediate.²

Closure. Membrane and particulate graft are not necessary. The site is left to heal by secondary intention.

Evidence

The literature on ERE today is robust.

The systematic review by Bassetti and colleagues (2016)⁵ analysed available studies on alveolar ridge splitting/expansion, documenting implant survival rates around 97% and a mean horizontal gain of approximately 3 millimetres. The documented complications — buccal cortex fracture, loss of expansion, crestal resorption — are rare when case selection and technique are rigorous.

The work of Crespi and colleagues (2015) on immediate loading after split crest² showed, in selected patients, survival rates comparable to those of deferred loading: a signal that the primary stability achievable with expansion is sufficient, in expert hands, to support loading.

The most recent international consensus — the review by Tolstunov et al. (2019)⁶ on horizontal and vertical augmentation techniques — places ridge expansion among the first options to consider in moderate horizontal atrophies, before more invasive alternatives.

The point is this: ERE is not a marginal technique. It is a technique with high-level literature behind it, and with outcomes equivalent to GBR in correct indications. I repeat this because still, in 2026, some say the contrary — and I have dedicated an entire article to dismantling those criticisms (Split Crest ERE: 98.1% Success but “Doesn’t Work”).

Limits

Honesty: ERE is not for everything.

It is not for vertical atrophy: expansion is two-dimensional, it does not add height. It is not for the rigid, medulla-free ridge: without elasticity, the cortex breaks. It is not for the clinician who does not practise it regularly: it is an operator-sensitive technique.

And it has always been a technique that is less “sellable” commercially than a full GBR packed with biomaterials, because it requires fewer products and more craftsmanship. Perhaps this is also why it remains undervalued in certain circles. I have discussed this here: Bone Expansion Is Not a Niche.

Further reading

This article is the entry point. The in-depth explorations I have scattered over the years in dedicated articles, which you can find below:

• Split Crest ERE: 98.1% Success but “Doesn’t Work” — the evidence, and why some pretend not to see it
• Split Crest: Is Partial Thickness Really Needed? — the flap, the periosteum, the critical choice
• Diamond Disc and Mandibular Expansion — the right instrument for the posterior mandible
• Periosteum and Ridge Expansion (Stricker’s lesson) — the lesson on vascularisation
• Bone Expansion Is Not a Niche — why it remains undervalued
• Expansion Is Magic: It Turns Back the Clock, Regenerates According to Nature — the narrative side of the technique
• Immediate Post-Extractive Crestal Sinus Lift with Xenograft — a close relative

And if you are a colleague and want to see it performed live, the osteo-mucosal expansion course in Frosinone is where you learn to do it, not just talk about it.

Operative conclusion

If you are a patient: before accepting a large bone graft, ask whether expansion is an option in your case. It is not always. But when it is, it is the simplest path.

If you are a colleague: the technique exists, it has solid literature, and it works. You do not need to believe in it. You need to select cases well, learn it from those who do it, and practise it.

Bone does not always need adding. Sometimes it just needs displacing.

---

References

1. Scipioni A, Bruschi GB, Calesini G. The edentulous ridge expansion technique: a five-year study. Int J Periodontics Restorative Dent 1994;14(5):451-9. PubMed
2. Crespi R, Bruschi GB, Gastaldi G, Capparé P, Gherlone EF. Immediate loaded implants in split-crest procedure. Clin Implant Dent Relat Res 2015;17 Suppl 2:e692-8. PubMed
3. Bruschi GB, Crespi R, Capparé P, Bravi F, Grande N, Gherlone E, Gastaldi G. Radiographic evaluation of crestal bone level in split-crest and immediate implant placement: minimum 5-year follow-up. Int J Oral Maxillofac Implants 2017;32(1):114-120. PubMed
4. Scipioni A, Bruschi GB, Calesini G, Bruschi E, De Martino C. Bone regeneration in the edentulous ridge expansion technique: histologic and ultrastructural study of 20 clinical cases. Int J Periodontics Restorative Dent 1999;19(3):269-77. PubMed
5. Bassetti MA, Bassetti RG, Bosshardt DD. The alveolar ridge splitting/expansion technique: a systematic review. Clin Oral Implants Res 2016;27(3):310-24. PubMed
6. Tolstunov L, Hamrick JFE, Broumand V, Shilo D, Rachmiel A. Bone Augmentation Techniques for Horizontal and Vertical Alveolar Ridge Deficiency in Oral Implantology. Oral Maxillofac Surg Clin North Am 2019;31(2):163-191. PubMed