Soft Tissue Integration With Natural Tooth-Shaped Abutments
Avishai Sadan, DMD • Thomas J. Salinas, DDS
When first introduced, implant dentistry achieved great
success in the treatment of completely edentulous patients.1-4 The
technique was eventually utilized to successfully replace missing teeth in
partially dentate patients.5,6 The development of abutment
connections was pioneered to enhance aesthetics while maintaining the hygiene
of the peri-implant tissues. Replacement of a single missing tooth in the
anterior maxilla is one of the most challenging procedures, since soft tissue
aesthetics, location and volume of available bone, prosthetic aesthetics,
phonetics, and occlusion must be considered.
The use of traditional abutment / prosthetic connections in
the replacement of a single missing tooth has been restricted by inadequate
interarch distance. The “UCLA” abutment was introduced to address the
difficulties in space restriction and axial alignment.7,8
Customization of the abutment with either metal or porcelain allowed the
development of the desired emergence profile and provided an option of
segmented or nonsegmented restoration.9 Cementable restorations
seemed to be more appropriate to maximize aesthetics in the anterior maxilla.
However, they required the use of the available abutments, which had a round
cross-section with a relatively straight emergence that caused a disparity
between the widest diameter of the intended restoration and the diameter of the
The dimensional disparity between the implants and the
postextraction sockets resulted in the development of abutments fabricated in a
shape similar to that of natural teeth.10 Abutment systems have been
recently introduced that are fabricated to the configuration of natural teeth
in the anterior maxilla. The systems permit the development of an aesthetic
emergence profile and contours that facilitate hygiene maintenance of maxillary
anterior implant-supported single-tooth restorations.
Since a considerable tissue deficiency frequently
accompanies the loss of a tooth in the anterior maxilla, grafting of the area
may be required. The extent of bone resorption indicates whether the implant
should be placed concomitantly with a bone graft or delayed until the bone
graft has healed.11 Due to the potential loss of papillae and other
soft tissue profiles, soft tissue replacement in these areas may be required.
When optimal soft tissue aesthetics around single-tooth implant restorations is
the treatment objective, techniques of regeneration with interpositional,12
subepithelial connective tissue,13 soft tissue onlay grafts,14
and a three-stage approach15 have offered varying degrees of
A proper treatment plan must include the selection of an
appropriate design for retrieval, from which the orientation of implant
placement can be verified with a radiographic stent/template and concurrent
tomogram or similar digital image of the site. Strict adherence to the surgical
stent can be accomplished by providing the surgeon with a serial drill guide.16
Since the concentricity of the original twist drill can be preserved in the
final tap drill, its use prevents the osteotomy site from migrating during
placement. The 2-mm pilot drill is used to initiate the procedure and to bur to
the appropriate depth. Since the prosthetic design dictates the orientation and
position of the implant, a system that allows abutment try-in at the time of
placement aids the surgeon in correct placement and angulation.
These important planning features are important when one is
selecting the appropriate implant and anatomical abutment system. The try-in
body for the respective abutment is selected at this stage to determine which
abutment configuration is most appropriate. The try-in may also have a role in
determining the extent of countersinking required (Figure 1). Serial-sized osteotomes may be
used in specific clinical circumstances to widen the osteotomy site while
preserving buccal cortical plate.17 The site is widened almost to
the final tap drill, for which only minimal bone is removed, promoting
stabilization of the implant fixture and the architecture of the facial
gingival complex (Figures 2 and 3).
Once the implant is in place, the 1.5-mm guide pins can be
inserted in the abutment try-in body and placed inside the fixture. The
selection of the most appropriate abutment can now be determined, particularly
if surgical indexing is used. Recording the position of the implant is helpful
in the development of soft tissue profiles following second-stage surgery. If
stability of the implant is acceptable at placement, recording of the implant
position with autopolymerizing resin can be performed carefully prior to
grafting and/or closure (Figure 4). The flat side of the hex should be oriented
to the facial aspect when utilizing the depicted anatomical abutment system.
Following polymerization, the surgical index can be attached
to the diagnostic cast with an adjoining implant analog to preserve the
position of the newly placed implant. A recess is created in the diagnostic
cast to approximate the shape of the implant body (Figure 5); it allows
placement of the surgical index / implant analog complex on the diagnostic
cast. Either resin or stone is used to anchor the implant analog in place. If
the try-in body configuration was determined at implant placement, abutment
selection will allow preparation of the abutment and the provisional
fabrication in the laboratory (Figure 6).
These specialized techniques can be utilized with single or
multiple missing teeth in any region. However, since these abutments are
available only for maxillary anterior dentition, the use of a customized
abutment may be necessary in other regions. It must also be determined whether
bone and/or soft tissue grafting will be required in order to anticipate
replacement resulting from future aesthetic and hygienic complications. This
technique should not be used with implants that are countersunk to greater
depths, since the removal of cement in these cases may be difficult, if not
impossible. The use of a nonsegmented screw-retained restoration or a ceramic
abutment may be an alternative in these circumstances.
The clinical procedure should be preceded by the evaluation
of any existing deficiencies. To determine the quantity of missing or malposed
keratinized tissue, soft tissue of the implant site is compared with that of
the adjacent dentition. Tomograms or similar digital imaging alternatives may
provide a clearer indication as to the extent of bone missing from the facial
cortical plate. A waxup will determine the position of the incisal edge,
cingulum form, cementoenamel junction, lingual concavity, and axial emergence.
The waxup is subsequently duplicated in stone, and a surgical stent/template is
It should be determined whether the intended restoration
will be cemented or screw-retained. Depending upon the size of the restorative
space for anterior teeth, a screw access may have to be placed in the cingulum
for aesthetic demands. If screw retention is required, the ideal access hole is
positioned between the incisal edge and the cingulum. Due to alveolar
resorption, an implant is often placed palatally. This frequently occurs in the
lateral incisor region because of its labial concavity. If a screw-retained
restoration is desired, the resultant prosthesis should be fabricated with a
ridge lap to simulate the free gingival margin.18 To achieve uniform
contours with the definitive restoration, a modified ridge-lap has to be
created, which complicates patient hygiene procedures (Figure 7). To retain the
external contours of the prosthesis in physiological and aesthetic limits,
cement-retained restorations are considered to be the norm for the anterior
Cemented restorations are preferable to screw-retained
restorations in the establishment of aesthetic contours and favorable gingival
profiles. If an alteration in the emergence profile is desired, a
screw-retained restoration requires a different abutment and the fabrication of
a new master model, while the cemented restoration may be adapted without the
recording of a new impression.19,20
The primary surgical procedure should be based on an
atraumatic flap design that preferentially excludes the papillae, yet allows
adequate visibility of the underlying bone. The stent should allow access from
the lingual aspect for adequate instrumentation and retain the facial surface
intact with the estimated position of the cementoenamel junction. When position
of the 2-mm pilot drill has been determined, the try-in abutment may be placed
to determine the appropriate configuration and countersinking. In the depicted
system, five abutment configurations are available--three for incisors and two
for cuspids and bicuspids.
Once the implant fixture is placed, its position can be
verified with the abutment try-in and a 1.5-mm guide pin. This assembly fits
within the implant body and gives a clear indication of the exact implant
position with respect to abutment selection. The level of countersinking can
also be verified prior to surgical indexing, grafting, and flap closure. The
abutment configuration is recorded, and an abutment can be fabricated in time
for the second-stage surgery without the need for an extensive inventory. If
the implant is mobilized or if residual material is allowed to remain in the
surgical site, surgical indexing may pose a risk to the success of implant
surgery. If a surgical index is made, however, the fabrication of a provisional
restoration is a time-efficient alternative to placement of a tissue-contouring
abutment. The indirect abutment is fabricated with a finish line 4 mm superior
to the implant platform, which may require preparation to retain the metal
surface below the tissue, since the balance of the emergence profile can be
created in the provisional restoration (Figure 8).
Single-tooth implant-supported restorations in the anterior
maxilla are planned with an appropriate diagnostic waxup. The timing of
surgical procedures should be strategically arranged to include concomitant
bone grafting, if required, and appropriate implant placement. Cases of this
type frequently require soft tissue grafting, particularly if the tooth has
been missing for a considerable length of time. The soft tissue grafting should
be performed following at least 3 to 4 months of integration. The implant
should essentially be integrated at this time, and split-thickness dissection
allows the placement of an interpositional connective tissue graft. If the
graft is performed following or simultaneously with the uncovery procedure,
interferences may be present and become a nidus for bacteria and potential
infection. In addition, the external tissue contours may be used to obtain an
improved aesthetic result.
The grafting technique utilized is dependent upon the type
and/or quality of tissue required--keratinized, interpositional bulk, attached,
etc. Soft tissue architecture is of crucial importance for the aesthetic
success in these cases, and grafting will have a limitation of volume based on
its blood supply.
Titanium abutments have demonstrated to be predictable,
durable, and biocompatible connections. The use of anatomical abutments is
helpful when the clinician is attempting to create a natural emergence with
porcelain restorations, due to the close approximation of these abutments with
the cervical shape of natural teeth. By using prefabricated healing abutments
and components, the uncertainties of soft tissue modification following
uncovering is restricted to a minimum. Retrieval techniques in cementable
prosthetics may rely on the use of an auxiliary tap screw to engage the
abutment through the existing tissues. This secures the restoration and, if a
provisional restorative cement is used, effectively seals any potential
Maxillary anterior single or multiple tooth implant supported
restorations create high aesthetic and hygienic demands for the patients and
the surgical/restorative team (Figures 9-10-11-12-13-14-15-16-17-18-19-20).
Appropriate implant selection and placement in this area is crucial for
restorability and patient hygiene maintenance. Provided the placement is
optimal, titanium abutments have demonstrated superb biocompatibility with soft
tissues and implant surfaces. However, the use of titanium restricts the
aesthetic potential of porcelain restorations, due to the dark metallic
abutments that are visible through the gingival tissue. In these cases, the
subgingival emergence of the tooth-shaped titanium abutments may be created and
finalized with porcelain to an anatomical shape. Since the configurations are
identical with healing abutments, impression posts, and definitive abutments,
only minimal or no soft tissue modifications are required following second-stage
surgery. Porcelain is a biocompatible substance, and utilization of subgingival
porcelain is the key to the health of periimplant tissues. The highly glazed
surface and the exceptional marginal adaptation of an all-ceramic system
further promote the health of the surrounding gingiva.
Professor, Department of Prosthodontics, Louisiana State University School of
Dentistry, New Orleans, Louisiana.
- Adell R, Leckholm U, Rockler B, et al.
A 15-year study of osseointegrated implants in the treatment of the edentulous
jaw. Int J Oral Surg 1981;10(6):387-416.
- Brånemark P-I, Zarb GA, Albrektsson T,
eds. Tissue Integrated Prostheses. Osseointegration in Clinical Dentistry. Carol Stream, IL:
Quintessence Publishing, 1985.
- Lindquist LW, Carlsson GE, Glantz PO. Rehabilitation of the edentulous mandible with a tissue integrated fixed
prosthesis: A 6-year longitudinal study. Quint Int 1987;18:89-96.
- Laney WR, Tolman DE,
Keller EE, et al. Dental implants: Tissue integrated prosthesis utilizing the
osseointegration concept. Mayo Clinic Proceedings 1986;61(2):91-97.
- Van Steenberghe D, Leckholm U, Bolender
C, et al. Applicability of osseointegrated oral implants in the rehabilitation
of partial edentulism: a prospective multi-center study on 558 fixtures. Int J Oral Maxillofac Impl 1990;5(3):272-281.
KH. Osseointegrated implants for stabilization of the partially edentulous
patient. J Canad Dent Assoc 1992;58:563-567.
- Lewis S, Beumer J, Perri G, Hornburg W.
Single tooth implant supported restorations. Int J Oral Maxillofac Impl
- Lewis S, Avera S, Engleman M, Beumer J.
The restoration of improperly inclined osseointegrated implants. Int J Oral
Maxillofac Impl 1989;4(2):147-152.
- Lewis S. Anterior single tooth
restorations. Int J Periodont Rest Dent 1995;15:30-41.
- Daftary F. Natural esthetics with implant
prostheses. J Esthet Dent
DA. The esthetic dental implant: Letting restoration be the guide. J Am
Dent Assoc 1995;126(3):319-325.
- Meltzer JA. Edentulous area tissue graft
correction of an esthetic defect: A case report. J Periodontol
- Abrams L. Augmentation of the deformed
residual edentulous ridge for fixed prosthesis. Compend Cont Dent Educ
- Seibert JS. Reconstruction of deformed,
partially edentulous ridges, using full thickness onlay grafts. Part I.
Technique and wound healing. Compend Cont Educ Dent 1983;4(5):437-453.
- Salama H, Salama M, Garber D, Adar P.
Developing optimal peri-implant papillae within the esthetic zone. Part I.
Guided soft tissue augmentation: The three-stage approach. J Esthet Dent
- Lazzara RJ. Effect of implant position on
implant restoration design. J Esthet Dent 1993;5(6):265-269.
- Saadoun AP, Le Gall MG. Implant site
preparation with osteotomes: Principles and clinical application. Pract
Periodont Aesthet Dent 1996;8(5):453-463.
- Engleman MJ. Clinical Decision Making and
Treatment Planning in Osseointegration. Carol
Quintessence Publishing; 1997:117.
- Misch CE. Screw-retained versus
cement-retained implant-supported prostheses. Pract Periodont Aesthet Dent
- Misch CE. Contemporary Implant Dentistry.
St. Louis, MO: Mosby; 1993:652-654.