The Last Teeth Standing: Preserving Architecture in the Transition from Natural Teeth to Implants

The First Day of Summer

The Last Teeth Standing: Preserving Architecture in the Transition from Natural Teeth to Implants

Today is the first day of summer.

The sun is shining, the sky is clear, and somehow the day already feels different.

I started the morning with 10 kilometers on the treadmill, trying to simulate what the mountain will demand from me in fifteen days. A treadmill is obviously not a mountain, but preparation always begins long before the climb itself.

And then came the best news of the day.

Sofia passed. Rodrigo passed. Henrique passed.

Each one with their own difficulties. Each one with their own journey.

But they all made it.

And perhaps that is why today felt like the right day to write about a case that also speaks about transitions, preparation and preservation.

Because this week we treated one of those cases that changes the way we see clinical dentistry.

A case that, in many ways, condensed almost everything modern implant dentistry has taught us over the last twenty years.

And, incidentally, a case in which I probably consumed half the stock of biomaterials available in the clinic.

The Hopeless Teeth That Preserved Everything

The patient had been under my care for many years.

He presented with what we traditionally call in Portugal a "horseshoe restoration", a large cemented metal-ceramic prosthesis supported by five natural teeth.

The second quadrant already contained three previously integrated implants, which remained perfectly functional.

The first step was naturally a complete clinical and CBCT evaluation.

Unfortunately, none of the remaining teeth could be preserved.

Both central incisors had undergone extensive apicectomies and previous endodontic treatment, with recurrent marginal caries.

The canines showed root fractures associated with old cast posts.

The premolar was equally compromised.

Biologically, all five teeth were hopeless.

And yet, paradoxically, these hopeless teeth had preserved something extremely valuable.

Architecture.

The gingival zeniths. The papillae. The emergence profiles. Nature had spent decades building this anatomy.

The challenge was no longer to save teeth.

The challenge was to preserve what the teeth had built.

Planning Begins with Photography

The smile line was relatively low. The cervical margins were not visible.

The buccal corridors were excessively filled. There was too much tooth and too little negative space.

This immediately revealed a horizontal overcontouring of the prosthesis that needed correction.

For several days, I struggled with the treatment plan.

Should the implants be placed in the existing edentulous spaces while preserving the teeth for provisionalization?

Or should the implants occupy the extraction sockets themselves?

Eventually, the answer became obvious.

If I wanted to preserve the emergence profiles and the soft tissue architecture, the implants had to replace the teeth.

Not the spaces between the teeth.

This decision, however, created another problem.

Primary stability.

The central incisors would not be an issue.

The canines were much less predictable.

And the premolar would inevitably leave part of the implant unsupported by bone.

Not an ideal scenario.

But preserving architecture rarely follows the easiest path.

Keeping a Hopeless Tooth

Initially, I had planned to extract tooth 16. But after some reflection, I changed my mind.

Despite its extensive periapical pathology and structural damage, this tooth still had one final mission.

It maintained posterior contacts. It preserved the bridge in the second quadrant.

And most importantly, it protected the anterior region from excessive loading.

Sometimes hopeless teeth still have value.

Not as permanent teeth.

But as temporary allies.

Immediate Loading Was Not the Answer

Because of the three existing implants in the second quadrant, the final implant distribution would not follow a continuous arch.

The AP spread would be compromised.

The center of rotation would become less favorable.

And knowing how strongly this patient functioned, immediate loading did not seem wise.

Just because we can load immediately does not mean we should.

Transitional Implants: Buying Time for Biology

The solution was surprisingly simple.

Three temporary implants measuring 1.8 × 10 mm.

Their mission was not to integrate. Their mission was protection. Protection of the definitive implants. Protection of the grafts. Protection of biology.

Divide and Conquer

One of the best decisions was to divide the treatment into two appointments.

The first appointment was purely prosthetic.

Removing the old metal-ceramic structure required almost ninety minutes.

A provisional restoration was relined over the remaining teeth.

Photographs were taken.

Canting was evaluated.

Incisal display was analyzed.

By the end of that appointment, I realized it had been the right decision.

On surgery day, there would be no metal to cut.

No distractions.

Only biology.

Surgery Day

Articaine with 1:100,000 epinephrine was administered buccally and 1:200,000 palatally.

A full-thickness buccal flap was elevated.

Importantly, no palatal flap was raised.

This is one of the secrets of these procedures.

Preserving the palatal tissues prevents excessive apical migration and allows the buccal tissues to be coronally advanced and stabilized around the customized healing abutments.

Five Teeth. Five Defects. Five Completely Different Strategies.

Tooth 21 was extracted atraumatically and preserved an intact socket.

Tooth 11 presented a small cervical fenestration, corresponding to a Type II extraction socket.

Tooth 23 developed a buccal dehiscence after extraction.

Tooth 13 exhibited complete destruction of the buccal plate.

Tooth 15 preserved almost all of its anatomy.

Five teeth.

Five defects.

Five completely different biological situations.

Implant Placement

Using a surgical guide, we started with the central incisors.

Two BLX implants were placed approximately 3.5 mm subcrestally.

This depth would later allow the placement of SRA abutments and individualized healing abutments.

The emergence profiles had already been designed in coDiagnostiX®, and it became obvious how different a truly customized healing abutment was from the standardized components available commercially.

Primary stability was excellent.

Tooth 23 received an immediate TLX NT Standard implant.

Its polished collar offers an interesting biological advantage, allowing connective tissue to develop against a machined surface.

Tooth 13 represented the greatest challenge. A large palatal lesion required meticulous curettage.

Residual infection is one of the hidden causes of failure in immediate implants.

Because regeneration was planned, flap elevation actually improved visualization and facilitated complete debridement.

After irrigation, the implant was intentionally positioned more palatally and later corrected prosthetically using a 17-degree SRA abutment.

The implant at tooth 15 was straightforward.

Radiographically and clinically, implant positioning was highly satisfactory.

But implant placement was only half of the story.

Four Defects. Four Different Regeneration Strategies.

Tooth 21

Intact socket.

Particulate graft material alone.

No membrane.

Tooth 11

Approximately 2 mm of buccal bone loss.

Particulate grafting combined with a resorbable membrane.

Tooth 23

Approximately 3 mm of buccal deficiency.

Particulate graft and a double-layer membrane technique.

Tooth 13

Complete absence of the buccal plate.

Guided bone regeneration.

Different defects.

Same biological principles.

Customized Healing Abutments

Four provisional cylinders were connected to the SRA abutments. Sofia had fabricated four individualized emergence profiles. Two for the central incisors. Two for the canines.

Using transparent acrylic and a small amount of flowable composite, these components were captured intraoperatively.

Each healing abutment contained a small channel that allowed the passage of a 6-0 monofilament suture.

This enabled the buccal flap to be coronally advanced and stabilized directly onto the healing abutment.

At that moment, this ceased to be simple implant surgery.

It became tissue engineering.

Transitional Implants

At sites 12, 22 and 14, three temporary implants were inserted.

Their only role was protection.

Nothing more.

And nothing less.

Prosthodontics: Knowing What Not to Load

By the end of surgery, the emergence profiles had already been created.

Therefore, the provisional restoration was aggressively relieved almost to the middle third of the crowns.

The objective was simple.

Maintain aesthetics. Avoid loading the definitive implants.

After relining, the provisional restoration was supported exclusively by the temporary implants.

Because these implants exhibited slight divergence, friction alone provided excellent retention.

No provisional cement was necessary. Occlusion was adjusted conservatively.

Perfection was not the objective Protection was.

The patient left the clinic with fixed teeth and unloaded implants.

Postoperative CBCT and panoramic radiographs beautifully illustrated the entire concept.

The Laboratory: Where Surgery Continues

Perhaps the most fascinating part of this case was not the surgery.

It was the laboratory.

Modern implant dentistry is no longer a conversation between the surgeon and the bone.

It is a conversation between the surgeon and the technician.

The process started by merging STL files with the CBCT inside coDiagnostiX®.

And immediately something became obvious.

Commercial anatomical healing abutments are rarely anatomical.

Because screw-retained restorations force implants into a more palatal position.

Primary stability often relies on the palatal plate.

As a result, emergence profiles are inherently asymmetrical.

More volume is needed buccally. Less volume exists palatally.

Nature is asymmetrical. Standard components are symmetrical.

And therein lies the problem.

Implant Depth Matters

The implant must be deep enough to allow placement of the intermediate abutment below the supracrestal tissue attachment.

Only then can the customized healing abutment capture approximately 2 mm of buccal tissue without creating excessive overcontours.

Implant depth is therefore dictated not by bone.

But by soft tissues.

Understanding the Tooth Before Removing It

The STL reveals the mesiodistal and buccopalatal dimensions of the tooth.

The roots become visible.

Combining this information with the CBCT allows visualization of the future supracrestal space.

In reality, customized healing abutments are designed before surgery.

Not after surgery.

They simply attempt to reproduce what nature had already created.

The Technician Continues the Surgery

Based on the implant positions, Sofia designed the emergence profiles.

The emergence profiles were dictated by the implants.

And the implants themselves had been dictated by the prosthetic requirements.

Everything was connected.

Surgeon and technician were working on the same restoration.

Only at different times.

After surgery and provisionalization, a new STL scan was obtained.

This scan no longer represented virtual planning.

It represented biological reality.

Using this information, a second provisional restoration would be fabricated.

More aesthetic.

More hygienic.

More individualized.

And more refined from an occlusal standpoint.

A B C - Clinical guided trough post extractions Bucal Plate morphology ( Andre Chen drawing)

Figure A. Immediate implant placement in an intact extraction socket.

A represents an immediate post-extraction socket with preservation of the buccal plate and bundle bone. Following flap elevation with a full-thickness mucoperiosteal flap, prosthetically driven implant placement is performed using a surgical guide. A screw-retained abutment (SRA) is connected to the implant and an intermediate screw (IS) supports the provisional cylinder (PC), onto which a customized anatomical healing abutment (CAHA) is bonded using flowable composite resin.

Bone graft material is then placed inside the existing bony envelope, occupying the jumping gap between the implant surface and the buccal socket wall, constituting an internal bone graft (IBG). Since the buccal plate is intact, no barrier membrane is required. An advanced coronal flap (ACF) is subsequently stabilized and secured to the customized anatomical healing abutment with a non-resorbable suture (NRS), allowing preservation of the biological width and development of the emergence profile while avoiding functional loading during healing.

This configuration represents the most favorable biological scenario, in which the native socket anatomy is preserved and regenerative procedures are confined within the existing osseous envelope.

Figure B. Immediate implant placement in a socket with partial loss of the buccal plate.

B represents an immediate post-extraction socket with a partial buccal wall defect, corresponding to approximately 2–3 mm of buccal bone loss. In this scenario, the socket can no longer be considered an ideal recipient site for purely internal bone grafting, since part of the regenerative compartment lacks bony containment.

A full-thickness mucoperiosteal flap is elevated on the buccal aspect to expose the defect. Prosthetically driven implant placement is performed using a surgical guide, followed by connection of the intermediate screw-retained abutment (SRA). A provisional cylinder (PC) is attached and a customized anatomical healing abutment (CAHA) is bonded to the provisional cylinder with flowable composite resin, establishing the future emergence profile.

Particulate bone graft material is placed both inside the extraction socket and externally over the area of buccal bone deficiency. Because the external graft lacks vestibular bony support, a resorbable membrane (RM) is placed to stabilize and protect the regenerative compartment, thereby allowing horizontal guided bone regeneration.

A coronally advanced flap (ACF) is then performed and stabilized directly onto the customized anatomical healing abutment using a non-resorbable suture (NRS), promoting maintenance of the biological width and soft tissue architecture during healing.

Importantly, in this configuration, as in all three biological situations illustrated, the palatal tissues are intentionally left untouched. No palatal flap is elevated. Preservation of the palatal periosteum and connective tissue complex maintains vascularity, minimizes apical migration of the tissues, and greatly facilitates coronal advancement and stabilization of the buccal flap.

This configuration represents the transition from contained regeneration to true guided bone regeneration, where the membrane becomes an essential component of the treatment rather than an optional adjunct.

Once the buccal plate is partially lost, regeneration no longer occurs within nature's envelope. The clinician must recreate that envelope.

Figure XC. Immediate implant placement in the absence of the buccal plate.

C represents the most challenging biological scenario, characterized by complete absence of the buccal plate. In this configuration, the defect extends from the apical region to the coronal aspect of the socket, with total loss of the vestibular osseous envelope.

Primary stability can no longer be obtained from the socket walls and therefore relies on apical anchorage in native bone. Implant positioning remains prosthetically driven and is performed using a surgical guide. Following implant placement, the intermediate abutment is connected. In the case of implant 23, a straight screw-retained abutment (SRA) was sufficient. In contrast, implant 13 required a more palatal and apical implant position to obtain primary stability, which necessitated prosthetic correction using a 17° angled SRA.

A provisional cylinder (PC) is connected to the intermediate abutment and a customized anatomical healing abutment (CAHA) is bonded to the provisional cylinder with flowable composite resin, thereby establishing the future emergence profile and providing support for soft tissue stabilization.

Given the complete absence of the buccal wall, a horizontal guided bone regeneration procedure is performed. Particulate bone graft material is placed throughout the entire extension of the defect, creating both an internal and an external graft compartment. Since no vestibular bone support exists, a resorbable membrane (RM) is used to stabilize and protect the particulate graft and to recreate the missing regenerative envelope.

An advanced coronal flap (ACF) is subsequently performed and stabilized directly onto the customized anatomical healing abutment using a non-resorbable suture (NRS). This approach allows coronal positioning of the soft tissues while maintaining the integrity of the palatal tissues, which are intentionally left untouched throughout the procedure.

Importantly, the palatal flap is never elevated. Preservation of the palatal periosteum and connective tissue complex minimizes apical migration of the tissues and facilitates tension-free coronal advancement of the buccal flap.

This configuration represents a situation in which the implant is no longer placed within the existing anatomy. Instead, the clinician is required to reconstruct the anatomy that has been lost.

In configuration A, nature provides the envelope.

In configuration B, the clinician repairs the envelope.

In configuration C, the clinician rebuilds the envelope.

The severity of the defect changes the regenerative strategy, but the biological principles remain unchanged: primary stability, emergence profile preservation, coronally advanced flap stabilization, and avoidance of functional loading.

Final Thoughts

Twenty years ago, this patient might have received a removable denture.

Ten years ago, we might have immediately loaded the implants.

Today, we understand something different.

Biology does not like shortcuts.

Modern implant dentistry is no longer about placing implants.

It is about orchestrating biology.

It is about transferring information.

From CBCT to STL.

From surgeon to technician.

From virtual planning to biological reality.

Because implants are merely pieces of titanium.

The true treatment lies elsewhere.

In preserving architecture.

Because architecture is what remains after the teeth are gone.

We do not replace teeth.We preserve architecture.