Basic implant surgery
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Transcript of Basic implant surgery
1
IMPLANT SURGICAL
PROCEDURE
2
CONTENTS General principles of implant surgery
Patient preparation Implant site preparationOne stage versus two stage implant
surgeries Two stage “submerged” implant
placementFlap designs, incisions and reflection Implant site preparationFlap closure and suturingPost operative careSecond stage exposure surgery
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One stage “non-submerged” implant placementFlap designs, incisions and elevation Implant site preparationFlap closure and suturingPostoperative care
Conclusion
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GENERAL PRINCIPLES OF IMPLANT SURGERY
Patient preparation
Implant site preparation
One stage Vs two stage implant surgery
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PATIENT PREPARATION
1. Explanation of risks and benefits to the
patient.
2. Written / Informed consent
3. Local or General Anesthesia depending
on patient’s needs.
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BASIC PRINCIPLES OF IMPLANT THERAPY1. Implants must be sterile and made of a biocompatible material
(e.g., titanium).
2. Implant site preparation should be performed under sterile
conditions.
3. Implant site preparation should be completed with an atraumatic
surgical technique that avoids overheating of the bone during
preparation of the recipient site.
4. Implants should be placed with good initial stability.
5. Implants should be allowed to heal without loading or micro-
movement (i.e., undisturbed healing period to allow for
osseointegration) for 2 to 4 or 4 to 6 months, depending on the
bone density, bone maturation, and implant stability.
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SURGICAL SITE PREPARATION1. Patient drape
2. Rinsing or swabbing the mouth with chlorhexidine
gluconate for 1 to 2 minutes immediately before the
procedure.
3. Atraumatic implant site preparation.
4. Avoid damage to bone or vital structures
5. Copious irrigation to avoid heating and debris
removal.
6. The implant must be placed in healthy bone.
7. The surgical site should be kept aseptic.
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OPERATIVE REQUIREMENTS1. Good operating light
2. Good high volume suction
3. A dental chair which can be adjusted by foot controls
4. A surgical drilling unit which can deliver relatively high speeds (up to
3000 rpm) and low drilling speeds (down to about 10 rpm) with good
control of torque
5. An irrigation system for keeping bone cool during the drilling process
6. The appropriate surgical instrumentation for the implant system being
used and the surgical procedure
7. Sterile drapes, gowns, gloves, suction tubing etc.
8. The appropriate number and design of implants planned plus an
adequate stock to meet unexpected eventualities during surgery
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OPERATIVE REQUIREMENTS
9. The surgical stent
10. The complete radiographs including tomographs
11. A trained assistant
12. A third person to act as a get things in between to
and from the sterile and non-sterile environment.
13. Light handles should be autoclaved or covered
with sterile aluminum foil.
14. The instrument tray and any other surfaces which
are to be used are covered in sterile drapes.
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ONE STAGE VS TWO STAGE TECHNIQUE
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ONE STAGE TECHNIQUE
In the one-stage
approach, the implant or
the abutment emerges
through the
mucoperiosteum/gingival
tissue at the time of
implant placement.
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ADVANTAGES OF ONE STAGE Easier Mucogingival management
around the implant. Patient management is simplified
because a second stage exposure surgery is not necessary.
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TWO STAGE TECHNIQUE
In the two-stage approach, the top of the
implant and cover screw are completely
covered with the flap closure.
Implants are allowed to heal, without loading or
micro movement, for a period of time to allow
for osseointegration.
The implant must be surgically exposed
following an undisturbed healing period.
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In areas with dense cortical bone and good initial implant
support, the implants are left to heal undisturbed for a period of 2
to 4 months, whereas in areas of loose trabecular bone, grafted
sites, and sites with lesser implant stability, implants may be
allowed to heal for periods of 4 to 6 months or more.
Longer healing periods are indicated for implants placed in less
dense bone or when there is less initial implant stability (i.e.,
slight looseness caused by limited bone-to-implant contact),
regardless of jaw or specific anatomic location.
In the second-stage (exposure) surgery, the implant is uncovered
and a healing abutment is connected to allow emergence of the
implant/abutment through the soft tissues, thus facilitating
access to the implant from the oral cavity.
The restorative dentist then proceeds with the prosthodontic
aspects of the implant therapy (impressions and fabrication of
prosthesis) after soft tissue healing.
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ADVANTAGES OF 2ND STAGE SURGERY Situations that require simultaneous bone augmentation
procedures at the time of implant placement because
membranes can be covered by primary flap closure,
which will minimize postoperative exposure.
Prevents movement of the implant by the patient, who
may inadvertently bite on the healing abutment during
the healing period (one-stage protocol).
Mucogingival tissues can be augmented if desired at the
second-stage surgery in a two-stage protocol.
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TWO STAGE “SUBMERGED” IMPLANT PLACEMENT The first stage ends by
Suturing So the implant remains submerged and isolated
from the oral cavity. Mandible implants – 2 to 4 months Maxillary implants – 4 to 6 months
Longer periods – less dense bone Less initial implant stability
Shorter periods – More dense bone Altered surface microtopography
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In second stage The implant is uncovered and a healing
abutment is connected to allow emergence of the implant through the soft tissue, thus facilitating access to the implant from the oral cavity.
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TWO STAGE “SUBMERGED” IMPLANT PLACEMENT Flap design, incisions, and elevation
Vary slightly depending on the location and objective of the planned surgery.
Crestal The incision is made from along the crest of the ridge,
bisecting the existing zone of keratinized mucosa Adv. Easy to manage, results in less bleeding, less
edema, faster healing. Suturing placed generally do not interfere with the
healing. Remote
The incision is made some distance from the planned osteotomy site.
Layer suturing is indicated to minimize the bone graft exposure.
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INCISIONS
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IMPLANT SITE PREPARATION A mucoperiosteal (full-thickness) flap is
reflected up to or slightly beyond the level of
the mucogingival junction, exposing the
alveolar ridge of the implant surgical sites.
Elevated flaps may be sutured to the buccal
mucosa or the opposing teeth to keep the
surgical site open during the surgery.
The bone at the implant site(s) must be
thoroughly debrided of all granulation tissue.
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Once the flaps are reflected and the bone is
prepared (i.e., all granulation tissue removed and
knife-edge ridges flattened), the implant osteotomy
site can be prepared.
A series of drills are used to prepare the osteotomy
site precisely and incrementally for an implant.
A surgical guide or stent is inserted, checked for
proper positioning, and used throughout the
procedure to direct the proper implant placement.
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Tissue management f or a two-stage implant placement. A, Crestal incision made along the crest of the ridge, bisecting the existing zone of keratinized mucosa. B, Full-thickness flap is raised buccally and lingually to the level ofthe mucogingival junction. A narrow, sharp ridge can be surgically reduced/contoured to provide a reasonably f lat bed f or the implant.
C, Implant is placed in the prepared osteotomy site.
D, Tissue approximation to achieve primary flap closurewithout tension
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IMPLANT SITE PREPARATION
Sequence of drills used for standard-diameter (4.0-mm) implant site osteotomy preparation:
round,2-mm twist, pilot, 3-mm twist, and countersink. Bone tap (not shown here) is an optional drill that is sometimes used in dense bonebefore implant placement.
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A series of drills are used to prepare the osteotomy site precisely and incrementally for an implant. A surgical guide or stent is inserted, checked for proper positioning, and used throughout the procedure to direct the proper implant placement.
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ROUND BUR A small round bur (or spiral drill) is used to mark
the implant site(s). The surgical guide is removed, and the initial marks are checked for their appropriate buccal-lingual and mesial-distal location, as well as the positions relative to each other and adjacent teeth.
Slight modifications may be necessary to adjust spatial relationships and to avoid minor ridge defects. Any changes should be compared to the prosthetically-driven surgical guide positions.
Each marked site is then prepared to a depth of 1 to 2 mm with a round drill, breaking through the cortical bone and creating a starting point for the 2-mm twist drill.
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ROUND BUR/ SPIRAL DRILL
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2MM TWIST DRILL
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TWIST DRILLS (TO ENLARGE THE OSTEOTOMY SITE TO TILL REQUIRED DIAMETER)
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PILOT DRILL
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GUIDE PINS
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DEPTH GAUGE
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COUNTER SINK DRILL
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BONE TAP
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As the final step in preparing the osteotomy site
in dense cortical bone, a tapping procedure may
be necessary.
With self-tapping implants being almost
universal, there is less need for a tapping
procedure in most sites.
However, in dense cortical bone or when placing
longer implants into moderately dense bone, it is
prudent to tap the bone (create threads in the
osteotomy site) before implant placement to
facilitate implant insertion and to reduce the risk
of implant binding.
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It is better to allow the threaded implant to
“cut” its own path into the osteotomy site.
Bone tapping and implant insertion are both
done at very slow speeds (e.g., 20 to 40 rpm).
All other drills in the sequence are used at
higher speeds (800 to 1500 rpm).
It is important to create a recipient site that is
very accurate in size and angulation.
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In partially edentulous cases, limited jaw opening or
proximity to adjacent teeth may prevent appropriate
positioning of the drills in posterior edentulous areas.
In fact, implant therapy may be contraindicated in some
patients because of a lack of inter occlusal clearance, lack of
interdental space, or a lack of access for the
instrumentation.
Therefore a combination of longer drills and shorter drills,
with or without extensions, may be necessary.
Anticipating these needs before surgery facilitates the
procedure and improves the results.
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When wide-diameter drills are used for implant
site preparation, it is advisable to reduce the
drilling speed, according to the manufacturer's
guidelines, to prevent overheating the bone.
Copious external irrigation is critical. In the
case of wide diameter implants, a specific pilot
drill is often indicated as a transition between
each of the subsequent wider drills.
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Implant site preparation (osteotomy ) for a 4.0-mm diameter, 10 mm length screw-type, threaded (external hex) implant in a subcrestal position. A, Initial marking or preparation of the implant site with a round bur. B, Use of a 2-mm twist drill to establish depth and align the implant. C, Guide pin is placed in the osteotomy site to confirm position and angulation. D, Pilot drill is used to increase the diameter of the coronal aspect of the osteotomy site.
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E, Final drill used is the 3- mm twist drill to finish preparation of the osteotomy site. F, Countersink drill is used to widen the entrance of the recipient site and allow for the subcrestal placement of the implant collar and cover screw. G, Implant is inserted into the prepared osteotomy site with a handpiece or handheld driver. note: In systems that use an implant mount, it would be removed prior toplacement of the cover screw. H, Cover screw is placed and soft tissues are closed and sutured
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WRENCH / RATCHET: FITS ON TOP OF FIXTURE MOUNT & USED TO TIGHTEN FIXTURE AFTER PLACEMENT.
44
IMPLANT FIXTURES
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COVER SCREW
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FLAP CLOSURE AND SUTURING
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Once the implants are inserted and the cover screws secured, the
surgical sites should be thoroughly irrigated with sterile saline to
remove debris and clean the wound.
Proper closure of the flap over the implant(s) is essential.
One of the most important aspects of flap management is
achieving good approximation and primary closure of the tissues
in a tension free manner.
This is achieved by incising the periosteum (innermost layer of
full-thickness flap), which is non-elastic.
Once the periosteum is released, the flap becomes very elastic
and is able to be stretched over the implant(s) without tension.
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One suturing technique that consistently provides the
desired result is a combination of alternating
horizontal mattress and interrupted sutures.
Horizontal mattress sutures evert the wound edges
and approximate the inner, connective tissue surfaces
of the flap to facilitate closure and wound healing.
Interrupted sutures help to bring the wound edges
together, counterbalancing the eversion caused by
the horizontal mattress sutures.
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POST OPERATIVE CARE
Simple implant surgery in a healthy patient usually
does not require antibiotic therapy.
However, patients can be premedicated with
antibiotics (e.g., amoxicillin, 500 mg three times a
day [tid]) starting 1 hour before the surgery and
continuing for 1 week postoperatively if the surgery
is extensive, if it requires bone augmentation, or if
the patient is medically compromised.
Postoperative swelling is likely after flap surgery.
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This is particularly true when the periosteum has been
incised (released).
As a preventive measure, patients should apply an ice
pack to the area intermittently for 20 minutes (on and
off) over the first 24 to 48 hours.
Chlorhexidine gluconate oral rinses can be prescribed to
facilitate plaque control, especially in the days after
surgery when oral hygiene is typically poorer. Adequate
pain medication should be prescribed (e.g., ibuprofen,
600 to 800 mg tid).
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Patients should be instructed to maintain a relatively
soft diet after surgery.
Then, as soft tissue healing progresses, they can
gradually return to a normal diet.
Patients should also refrain from tobacco and alcohol
use at least 1 week before and several weeks after
surgery.
Provisional restorations, whether fixed or removable,
should be checked and adjusted so that
impingement on the surgical area is avoided.
52
SECOND STAGE EXPOSURE SURGERY For implants placed using a two-stage
“submerged” protocol, a second-stage
exposure surgery is necessary after the
prescribed healing period.
Thin soft tissue with an adequate amount of
keratinized attached gingiva, along with
good oral hygiene, ensures healthier peri-
implant soft tissues and better clinical
results
53
OBJECTIVES OF SECOND STAGE TECHNIQUE
1. To expose the submerged implant without
damaging the surrounding bone.
2. To control the thickness of the soft tissue
surrounding the implant.
3. To preserve or create attached keratinized
tissue around the implant.
4. To facilitate oral hygiene.
5. To ensure proper abutment seating.
6. To preserve soft tissue aesthetics.
54
SIMPLE CIRCULAR “PUNCH” INCISION In areas with sufficient zones of keratinized tissue,
the gingiva covering the head of the implant can
be exposed with a circular or “punch” incision
Alternatively, a crestal incision through the middle
of the keratinized tissue and full-thickness flap
reflection can be used to expose implants.
This latter approach may be necessary when bone
has grown over the implant and needs to be
removed.
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Clinical view of stage two, implant exposure surgery in a case with adequate keratinized tissue. A, Simple circular “punch” incision used to expose implant when sufficient keratinized tissue is present around the implant(s). B, Implant exposed. C, Healing abutment attached. D, Final restoration in place, achieving an esthetic result with a good zone of keratinized tissue.
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Clinical v iew of stage two implant exposure surgery in a case with inadequate keratinized tissue. A, Two endosseous implants were placed 4 months previously and are ready to be exposed. B, Two vertical incisions are connected by crestal incision.C, Buccal partial thickness flap is sutured to the periosteum apical to the emerging implants. D, Gingival tissue coronal to the cover screws is excised using the gingivectomy technique. E, Cover screws are removed, and heads of the implants are cleared. F, Abutments are placed. Visual inspection ensures intimate contact between the abutments and the implants.
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G, Healing at 2 to 3 weeks after second-stage surgery .
H, Four months after the final restoration. Note the healthy band of keratinized attached gingiv a around the implants.
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PARTIAL THICKNESS REPOSITIONED FLAP If a minimal zone of keratinized tissue exists at
the implant site, a partial-thickness flap technique can be used to fulfill the objective of the second-stage surgery (exposing the implant) while increasing the width of keratinized tissue.
A partial-thickness flap is then raised in such a manner that a nonmobile, firm periosteum remains attached to the underlying bone. The flap, containing a narrow band of keratinized tissue, is then repositioned to the facial side of the emerging head of the implant and sutured to the periosteum with a fine needle and resorbable suture such as a 5.0 gut suture
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A partial-thickness flap is apically displaced and sutured to the periosteum without exposing the alveolar bone.
A free gingival graft may be harvested from the palate and sutured to the periosteum on the labial surface of the implants to increase the zone of keratinized tissue.
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A, Partial-thickness f lap is created from the lingual aspect of thecrest toward the labial surf ace in order to preserve the keratinized tissue on the crest (over the implant). note: This tissue might be excised in a simple implant exposure.
B, The split-thickness f lap is repositioned to the labial surf ace. C, The f lap is sutured to the periosteum at a more apical position preserving the amount of keratinized tissue (arrows).
Finally , the remaining connectiv e tissue over the cover screw (B) is excised with a sharp blade to expose the implant. Care should be taken to avoid removing keratinized tissue from the lingual aspect of the implant.
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After the flap is repositioned and secured with periosteal sutures, the excess tissue coronal to the cover screw is excised, usually with a surgical blade.
When the excess tissue over the cover screw is removed or displaced, the outline of the cover screw is visible.
A sharp blade is used to eliminate all tissues coronal to the cover screw.
The cover screw is then removed, the head of the implant is thoroughly cleaned of any soft or hard tissue overgrowth, and the healing abutments or standard abutments are placed on the implant
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POST OPERATIVE CARE remind the patient of the need for good
oral hygiene around the implant and adjacent teeth.
rinse can be used to enhance oral hygiene for the initial few weeks after implant exposure.
oral hygiene procedures to avoid dislodging any repositioned or grafted soft tissues.
any direct pressure or movement directed toward the soft tissue from a provisional prosthesis can delay healing and should be avoided.
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Impressions for the final prosthesis fabrication can begin about 2 to 6 weeks after implant exposure surgery, depending on healing and maturation of soft tissues.
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ONE STAGE “NON-SUBMERGED” IMPLANT PLACEMENT
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In the one-stage implant surgical approach, a second implant exposure surgery is not needed because the implant is exposed (per gingival) from the time of implant placement
In the standard (classic) implant protocol, the implants are left unloaded and undisturbed for a period similar to that for implants placed in the two-stage approach (i.e., in areas with dense cortical bone and good
initial implant support, the implants are left to heal undisturbed for a period of 2 to 4 months,
whereas in areas of loose trabecular bone, grafted sites, and/or minimal implant support, they may be allowed to heal for periods of 4 to 6 months or more).
66
In the one-stage surgical approach, the implant or the healing abutment protrudes about 2 to 3 mm from the bone crest, and the flaps are adapted around the implant/abutment.
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FLAP DESIGN, INCISIONS, AND ELEVATION The flap design for the one-stage surgical
approach is always a crestal incision bisecting the existing keratinized tissue.
Facial and lingual flaps in posterior areas should be carefully thinned before total reflection to minimize the soft tissue thickness (if needed or desired).
The soft tissue is not thinned in anterior or other esthetic areas of the mouth to maintain tissue height and to minimize metallic implant components from showing through tissue.
68
IMPLANT SITE PREPARATION The primary difference is that the
coronal aspect of the implant or the healing abutment (two-stage implant) is placed about 2 to 3 mm above the bone crest and the soft tissues are approximated around the implant/implant abutment.
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FLAP CLOSURE AND SUTURING The keratinized edges of the flap are
sutured with single interrupted sutures around the implant.
Depending on the clinician's preference, the wound may be sutured with resorbable or nonresorbable sutures.
When keratinized tissue is abundant, scalloping around the implant(s) provides better flap adaptation.
However, if minimal keratinized tissue exists in an area, tissues should remain thick and soft tissue augmentation may be indicated.
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POST OPERATIVE CARE The postoperative care for one-stage
surgical approach is similar to that for the two-stage surgical approach except that the cover screw or healing abutment is exposed to the oral cavity.
Patients are advised to avoid chewing in the area of the implant.
Prosthetic appliances should not be used if direct chewing forces can be transmitted to the implant, particularly in the early healing period (first 4 to 8 weeks).
71
CONCLUSION It is essential to understand and follow
basic guidelines to achieve osseointegration predictably.
Fundamentals must be followed for implant placement and implant exposure surgery.
These fundamentals apply to all implant systems.
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REFERENCES Newman, Takei, Klokkevold, Carranza.
Carranza’s Clinical Periodontology, 10th Edition and 11th Edition
Lindhe, Lang, Karring. Clinical Periodontology & Implant Dentistry, 5th Edition.
Carle E. Misch. Contemporary Implant Dentistry. 3rd edition.