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6 Checklist and Step-by-Step Protocol to Maximize Impression Accuracy

6 Checklist and Step-by-Step Protocol to Maximize Impression Accuracy

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P. Papaspyridakos and T. R. Schoenbaum






Fig. 10.3 (a) Missing right lateral and central incisors and left central incisor (#7, 8, and 9) were

replaced with two dental implants for a three-unit implant-supported fixed dental prosthesis (FDP).

After successful osseointegration, peri-implant soft tissue conditioning was done for a period of

3 months with a provisional screw-retained FDP. (b) Partially edentulous area after peri-implant

soft tissue conditioning. (c) Customized impression copings duplicating the transmucosal part of

the provisional implant FDP. The indirect technique was used for fabrication of the customized

copings. (d) Customized impression copings placed intraorally, after removal of the provisional

implant FDP. Copings are splinted together with prefabricated light polymerized resin bar, in order

to enhance the accuracy of the implant impression. Minimal amount of light polymerizing resin

was used to lute the prefabricated resin bars to the copings. (e) Working cast poured only in stone

without soft tissue moulage. The customized impression copings have captured the transmucosal

part of the provisional implant FDP, guiding the laboratory technician to precisely duplicate the

transmucosal part into the emergence profile of the final FDP. (f) Screw-retained final FDP seated

on the working cast. The emergence profile and transmucosal contours of the final FDP are a duplicate of the provisional FDP, captured with the customized implant impression. Note the palatal

windows to confirm accurate seating of the FDP to the implant prosthetic platforms

10  Enhanced Implant Impression Techniques to Maximize Accuracy



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10  Enhanced Implant Impression Techniques to Maximize Accuracy


46. Joda T, Bragger U. Digital vs. conventional implant prosthetic workflows: a cost/time analysis.

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connection implant prostheses with various divergent angles. Int J Oral Maxillofac Implants.


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length, and impression material on the dimensional accuracy of implant impressions: an

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56. Burns J, Palmer R, Howe L, Wilson R. Accuracy of open tray implant impressions: an in vitro

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Implants. 2010;25:771–6.

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casts generated with splinted and non-splinted impression techniques for edentulous patients:

an optical scanning study. Clin Oral Implants Res. 2012;23:676–81.

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P. Papaspyridakos and T. R. Schoenbaum

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Emergence Profile of the Implant

Abutment and Its Effects

on the Peri-­implant Tissues


Todd R. Schoenbaum and Sam Alawie


The emergence profile is the portion of the implant-abutment-restoration complex that extends from the bone crest to the free gingival margin. Generally this

area is made up of the abutment, though in screw-retained restorations, it is part

of the restoration as a whole. This area is critical to the long-term health and

aesthetics of the rehabilitation in the aesthetic zone. The shape of the emergence

profile is responsible for creating and maintaining the soft tissue architecture.

This proves especially important in the immediate load treatment scenario. It is

critical that the restoring doctor have and understanding of the effects the emergence profile will have on the positioning of the soft tissues. Changes to the

emergence profile (particularly during the healing stages) can be strategically

used to move the tissues apically or coronally and to shape the papilla.

Following surgical placement of the implant and any additional augmentation, the

fine-tuning of the soft tissues (Fig. 11.1) will be largely dependent on the emergence

profile of the abutment (Fig. 11.2). In the aesthetic zone, this is a process best accomplished through the use of a proper provisional restoration or custom healing abutment. When sufficient implant stability exists at placement (i.e., ISQ > 65) [1], it is

generally easier to preserve and maintain the peri-implant soft tissues with an immediately placed provisional restoration. In cases where implant stability is questionable, the implant should be treated in a two-stage approach or with a custom healing

T. R. Schoenbaum

Division of Constitutive and Regenerative Sciences, University of California, Los Angeles,


e-mail: tschoenb@ucla.edu

S. Alawie

Owner/Ceramist Beverly Hills Dental Lab, Beverly Hills, CA, USA

© Springer International Publishing AG, part of Springer Nature 2019

Todd R. Schoenbaum (ed.), Implants in the Aesthetic Zone,




Fig. 11.1 Successful

treatment of implants in the

aesthetic zone requires

proper shaping of the soft

tissue with the provisional

restorations. The surgical

foundation sets the stage for

the prosthetic fine-tuning of

the gingiva. Inadequate bone

and soft tissue cannot be

overcome with tissue


Fig. 11.2  The emergence

area of the abutment is

defined by the area from

the head of the implant to

the free gingival margins

(here, highlighted in blue).

This area is responsible for

the final shaping of the

peri-implant tissues

T. R. Schoenbaum and S. Alawie

11  Emergence Profile of the Implant Abutment and Its Effects


abutment. In the latter case, special care must be given to ensure that the removable

provisional restoration does not negatively affect the soft tissues during maturation

and osseointegration. The shape of the emergence profile can be altered to move the

tissues to the desired position (with some genetic and biologic limitations) [2–4];

however, removal and alteration of the abutment should be delayed until at least

3 months after implant placement, and the number of times should be limited [5].

There is solid histological evidence that repeated removal of components from the

implant traumatizes the tissues and results in significant loss of bone and soft tissue.

This is especially true during the first few months of healing and maturation. Dr. Vela

and Dr. Rodriguez provide an in-depth look at this process in the last chapter.

This chapter will focus on the emergence profile of the provisional restoration

fabricated and delivered at the time of immediate implant placement to replace a

single tooth in the aesthetic zone. Similar concepts should be applied for the use of

a custom healing abutment or delivery of a provisional restoration at the stage 2

surgery. More information on the fabrication of provisional restorations can be

found in Chap. 8.

11.1 The Peri-implant Tissues: Tooth vs. Implant

Surrounding the natural tooth is a densely collagenous gingiva made up of type 1

collagen. The periodontal gingival fibers are anchored into the cementum on the

root surface via Sharpey’s fibers, the same mechanism through which the periosteum is attached to the underlying bone. The gingival fibers serve to protect the

tooth from the oral environment and provide anchorage for the gingiva. The fibers

are categorized by their location and orientation into five groups: gingivodental

fibers, transseptal fibers, semicircular fibers, transgingival fibers, and circular fibers.

All but the last type (circular fibers) insert into the cementum of the tooth root. This

is important to note, as the circular fibers are the only type present around the dental

implant [6–8]. The other fiber types are still present around the implant, but upon

encountering the implant surface lacking cementum, they persist in encircling the

implant, functionally becoming circular fibers [9]. Lacking cementum and any

mechanism for proper insertion of the fibers, this leaves the implant more vulnerable to trauma from the oral environment. This also will leave the peri-implant gingiva less stable and more prone to recession.

As the soft tissues mature, the myofibroblasts contract the length of the circular

fibers. This contraction will take place over the weeks following surgery [9].

Ultimately, what develops is analogous to an O-ring and serves as the only means of

protecting the bone-implant interface. In older flared neck implant designs, the contraction and tightening of the circular fibers moved the “O-ring” apically, taking the

bone and soft tissue with it [10]. This results in the typical bone loss to the first

thread. The reason the bone is lost to the first thread in older implant designs is

likely due to this being the first place on the implant where a tightening O-ring finds

a broad base. In more modern implant designs with abutments that are narrower

than the implant base, the O-ring tightens at that position, generally resulting in


T. R. Schoenbaum and S. Alawie

reduced losses of the bone and soft tissue. Further innovation of this concept is

described in the last chapter.

The circular fiber O-ring must be disturbed as little as possible. As described by

Dr. Abrahamsson’s histological study [5], repeated (non-traumatic) disturbances of

this area result in significant amounts of bone and soft tissue loss. The effects appear

to be most dramatic in the first months following placement.

11.2 P

 latform Switched Implants and the Narrow

Abutment Concept

At a basic level, the “platform-switched” (PS) implant design is one in which the

abutment is a narrower diameter than the implant at the interface. Most (though not

all) data show that this design maintains peri-implant bone levels better than older

designs [11–16]. This works by a few mechanisms (Fig. 11.3). One, the PS implant

moves the implant-abutment-junction (IAJ) medially, away from the bone. In

nearly every two piece implant ever tested long term, there is a bacterial exudate

External Hex design


Internal, conical,

platform switch design






Fig. 11.3  On the left side of this diagram, an older, external hex connection implant is represented; while on the right, an internal, conical, platform-switched connection implant is depicted.

The evolution from external hex to the internal conical PS design was brought about in an attempt

to reduce bone loss and screw loosening. This implant has the following advantages: (a) The

implant-abutment-junction (IAJ) is located medially, away from the bone. (b) The head of the

implant acts like a shelf where the circular peri-implant fibers can tighten without slipping down

to the first thread. (c) The connection is generally longer and more robust, resulting in less movement and leakage of the abutment over time. (d) The emergence area of the abutment is narrower,

allowing more room for the bone, peri-implant tissues, and blood supply

11  Emergence Profile of the Implant Abutment and Its Effects


that is pumped out from inside the implant at this junction [14, 17]. Moving the IAJ

away from the bone may lessen the insult on the bone. Two, the PS implant results

in a shelf upon which the gingival fiber O-ring tightens [9, 10]. This is analogous

to the first thread in older implant designs but located more coronally and thus

allows the bone to be maintained at a higher level. Three, many PS implants were

designed in conjunction with more robust connections (compared to the older

external hex designs). Some of these connections have a tapered interface which

seems to increase the rigidity and durability of the IAJ. This is commonly referred

to as a “Morse taper” design, though most implants do not actually have connections that fit any of the 1.5° Morse taper specifications. Nevertheless, the long

internal connections seem to produce less leakage at the IAJ compared to the short

external hex connections [17, 18]. Lastly, the PS implant, by design, has an abutment that is narrower than the implant. The smooth surface of the titanium (or Zr

or Au) abutment is not amenable to bony attachment, so moving this non-integrating surface away from the bone allows the bone to be maintained at a higher position. Conversly, in older style implants the abutment widens directly off the IAJ,

which forces the bone to reestablish at a lower position.

The narrowed abutment concept is an attempt to forgo the dimensions of the

preexisting root and instead create a peri-implant environment that is more suitable

to the unique soft tissue around an implant. PS implants have narrowed abutments

by design, but even some non-PS implants can (and should) have the emergence

area of the abutment narrowed [3].

The theoretical rational for the narrow abutment is that it allows a greater volume of soft tissue to encircle and protect the implant. This greater volume allows

more room for the initial blood clot to stabilize, allows more room for postoperative swelling, and allows more room for blood supply of the peri-implant tissues

[9, 19]. The above rational is a theory only; we do not yet have the science to

explain precisely why narrowed abutment emergence areas generally preserve the

bone and soft tissue at higher levels. Though the approach may be evolving (see

Chap. 16), currently suggested emergence designs should start narrow out of the

implant and progress through a “wine glass” shape as they approach their widest

dimension at the gingival margin. This design allows the additional subgingival

space for soft tissues and blood supply while providing proper support of the


If a cement-retained crown is to be used, the margins of the abutment should be

placed no deeper than 1  mm subgingival [20, 21] as explained in Chap. 12. If a

screw-retained restoration is to be used, the technician must pay special attention to

the emergence area. It is quite common to see less experienced or less attentive

technicians create restorations that are grossly overcontoured in the emergence area

(Fig. 11.4). This makes delivery of the restoration difficult and may require additional surgical procedures to complete. It also puts extreme pressure on the peri-­

implant tissues. In the short term, this pressure causes blanching and is uncomfortable;

in the long term, it results in unnecessary apical migration of the bone and gingiva.

These subtle changes in the emergence shapes can be skillfully used to fine-tune the

position of the soft tissue in the aesthetic zone.

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6 Checklist and Step-by-Step Protocol to Maximize Impression Accuracy

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