Immediate Maxillary Molar Implant Placement with Simultaneous Crestal

Approach Maxillary Sinus Bone Graft and Flapless Extraction

Jone Kim, DDS, MS

INTRODUCTION P.I. Bränemark introduced the idea of

osseointegration when he noticed the

incorporation of titanium with bone

tissue.1 The concept of osseointegration

revolutionized the replacement of missing

teeth with dental implants. Greater

understanding in bone and soft tissue

physiology, accelerated by technological

advances, has resulted in significant

improvements in dental implant surgery;

enabling a reduction in the number of

surgeries with less invasive surgical

techniques, optimized esthetics, and

decrease in the length of total treatment

time from extraction to final restoration.

Contemporary implant surgeons employ

less traumatic surgical techniques, place

implants immediately, and combine

multiple surgical techniques with fewer

surgeries.

The posterior maxillary molar site is

particularly challenging due to reduced

alveolar bone and the presence of the

maxillary sinus. A ridge preservation bone

graft and/or a maxillary sinus bone graft is

often required prior to implant placement,

complicating immediate implant

placement. Simultaneous flapless

extraction, crestal sinus lift, immediate

implant placement and ridge preservation

can be combined into one surgical visit for

the reconstruction of posterior maxillary

molars with appropriate preoperative

evaluation and meticulous surgical

technique.

EXTRACTION There is a theoretical advantage to flapless

extractions in decreasing bone resorption.

Canine studies comparing flapped versus

flapless extractions of second, third and

fourth premolars without bone grafting or

implant placement demonstrate no

significant difference in horizontal and

vertical bone loss. 2-4, 5 However, canine

studies comparing flapped versus flapless

extraction of more anterior first and

second premolars demonstrates a

significant difference with less bone

resorption with the flapless technique. 6 A

plausible explanation for this difference

between the two studies may be that the

stripping of the periosteum in areas of

thinner buccal bone in the more anterior

portion of the maxilla causes greater bone

resorption. Studies have shown that thin

buccal bone (< 1 mm) has more bone

resorption compared to thicker bone (> 1

mm).7-12 In addition to alveolar bone

resorption, full thickness flap may lead to

marginal recession at the adjacent teeth,

defective papillae and loss of keratinized

mucosa.13

Flapless surgery makes it simpler to bone

graft the socket than flapped surgery. The

flapless extraction socket is basically an

empty cavity where bone grafting particles

can be placed with ease and with less

mobility. In addition, since no incisions are

made, a flapless extraction results in less

surgical trauma, shorter surgical time, no

need of suturing and decreased swelling

and pain. Because of these advantages,

the flapless extraction technique should be

considered for all teeth that require an

extraction, even if the extraction site is not

for socket management or immediate

implant placement.

However, the most important aspect of the

extraction, in the author’s view, is not

whether the flap is made or not but rather

minimizing removal of bone. Therefore, the

extraction technique should focus on

preserving the alveolar bone, especially

the buccal and interradicular bone. Among

the socket bony walls, buccal bone is the

thinnest and will, therefore, resorb more

than other bony walls, and the

preservation of interradicular bone is

critical for immediate molar implant

placement after the extraction.7,9,14,15 If the

flapless extraction is too difficult, it is

better to make a minimal flap and remove

less bone than to do a flapless extraction

with more bone removal. If the flapless

extraction can be achieved with no bone

removal, then this should give the best

clinical outcome.

RIDGE PRESERVATION BONE GRAFT (RPBG) After extraction, the surrounding alveolar

bone goes through stages of remodeling

resulting in alveolar dimensional

changes. 16-18 Cardaropoli et al. 17 and

Araujo and Lindhe,18 demonstrate

horizontal and vertical bone resorption is

from loss of bundle bone within two weeks

after extraction. The crestal part of the

buccal bone is solely made up of bundle

bone, whereas lingual bone is comprised of

lamellar and bundle bone. After extraction,

since the crestal part of the buccal bone is

made primarily up of bundle bone,

increased bone resorption is observed in

buccal bone compared to lingual bone. 17-24

Immediate bone grafting is performed

after the extraction to preserve the

alveolar ridge, to minimize future bone

grafting, and increase the success of the

implant surgery. There is horizontal bone

reduction of 32% at three months, and 29-

63% at six to 12 months after

extraction.18,19,25-30 There is 11-22%

vertical bone resorption observed at six

months post-extraction and increasing

vertical resorption with multiple

extractions.19,22,31,32 Ridge preservation

bone grafting (RPBG) is a predictable

surgical modality to preserve the alveolar

bone after the extraction and allow for

wider and longer implant placement.19,33-37

In a recent randomized controlled clinical

trial, 48 implants were placed into either

RPBG sites or spontaneously healed

extraction sites four months after tooth

extraction. All implants survived at the one

year follow up, but during surgery, 14/24

(58%) spontaneously healed extraction

sites required additional bone grafting,

whereas only 1/24 (7%) needed additional

bone grafting in RPBG sites.38

There is an inverse correlation, resulting in

thinner buccal bone showing a two-fold

increase in horizontal bone loss compared

to thicker buccal bone in spontaneous

healed sites. Whether there is thick or thin

buccal bone, without bone grafting there is

an average of 4.04 mm horizontal

reduction.39 There is no correlation

between the thickness of the buccal bone

and alveolar bone loss in RPBG sites. In an

RPBG site there is an average of 0.71 mm

horizontal bone reduction. RPBG is able to

compensate for alveolar bone contraction

for both thin and thick buccal bone plates.

Therefore, what is important is not the

thickness of the buccal plate, but rather

whether or not RPBG was performed after

the extraction.

RPBG ideally should be performed in a

flapless manner to prevent horizontal bone

loss and maintain keratinized gingiva. In a

prospective randomized clinical trial that

compared flapped and flapless RPBG,

horizontal bone loss was 3.5 + 0.9 mm

and 1.7 + 0.6 mm for the flapped and

flapless approach, respectively.13 In

addition, the flapless technique showed an

increased width of keratinized gingiva

compared to pre-operative measurement,

whereas the flapped approach showed

decreased width. However, the flapped

group had a slightly less vertical buccal

bone reduction compared to flapless (-0.6

+ 0.7 vs. -1.1 + 0.9 mm), which was

statistically significant.

Even though autogenous bone is the gold

standard for bone grafting, many bone

graft alternatives such as xenograft,

allograft, alloplast , and bone

morphogenetic protein have been used in

RPBG. Currently, there is no consensus on

one bone graft material being superior to

the others. 29,33,37,40-47 No matter which

bone grafting material or surgical

technique is utilized, the ultimate goal of

RPBG is to preserve the alveolar bone for

future implant placement reducing the

need for additional bone augmentation at

the time of implant placement. 6,48-50

IMMEDIATE IMPLANT PLACEMENT In the beginning stages of implant surgery,

implants were primarily placed in a

delayed manner. Extraction sockets healed

for several months prior to implant

placement. Implants placed in a delayed

approach have a high success rate.51-

55 The first clinical study of immediate

implant placement was published in

1978.56 Surgical techniques have evolved

along with increased knowledge of bone

healing in the extraction site to improve

the immediate placement of dental

implants with predictable results7,26,57-

65 Short term survival rates and clinical

outcomes are similar in both immediate

and delayed approaches.63 Advantages of

immediate implant placement include the

reduction in the number of surgeries and

treatment time, preservation of alveolar

height and width, optimal gingival esthetic,

ideal implant placement and patient’s

convenience.47,59,66-72 There is more

favorable bone healing and improvement

in soft tissue contour with immediate

placement.26

One of the major concerns with immediate

implant placement is the presence of

infection at the extraction

site.73 Successful outcomes have been

demonstrated with placement of implants

placed into extraction sites with periapical

lesions.5,74-76 A retrospective study of 418

immediate implants placed into extraction

sites with periapical lesions demonstrated

a 97.8% survival rate with mean follow up

of 67 months. 77 Immediate implant

survival rates are similar for extraction

sites with or without perapical lesions.

There are several factors that are

important to ridge alteration and survival

after immediate implant placement:

thickness of buccal wall, horizontal bone

gap and initial primary implant

stability.7,57,63,78Thicker bone in the buccal

wall resulted in less resorption of the

buccal wall, which will decrease the chance

of dehiscence and other implant

complications.7,9,39,78,79 In the posterior

maxilla there will frequently be a horizontal

gap after immediate implant placement

due to the fact that the dimension of the

socket is larger than the diameter of the

implant.

For maxillary first molar, the average

mesio-distal and bucco-lingual

measurement is 10.4 and 11.5 mm,

respectively. 80 If the gap is within 2 mm,

after implant placement, spontaneous

healing without bone grafting can occur.57,

81 If the gap is wider than 2 mm, bone

grafting is recommended for immediate

implant placement after extraction in order

to minimize bone resorption.63 Adequate

primary stability is another critical factor

for a successful clinical outcome in an

immediate implant placement and loading

of the implant.82, 83 Currently, studies

demonstrating that primary stability is not

crucial with implants with special types of

surface treatment have only been done on

delayed implant placement not on

immediate implant placement. 84,85

Pre-operative and post-extraction

evaluation of the socket and bone is

important for determining if primary

stability of the implant can be attained. For

immediate molar implant placement after

extraction, besides vital structures such as

the maxillary sinus, adequate dimensions

of the alveolar bone, particularly of

interradicular bone, are crucial for

achieving primary stability of the

implant.15,86 Primary stability of the implant

is achieved by placing the implant in the

interradicular bone. Anatomical dimensions

of the interradicular bone will depend upon

tooth and trunk length and root

morphology;80 the more divergent the

roots are the wider the interradicular bone.

Vertical length of the interradicular bone

can be limited by pneumatization of

maxillary sinus. The location of

interradicular bone is usually the ideal site

for implant placement. When there is an

absence or inadequacy of interradicular

bone for immediate molar implant

placement, the surgeon may attempt to

place the implant in one of the root

sockets. However, placing the implant at

an off-angle will increase the magnitude of

force to the implant and surrounding

bone.87 In addition, an implant that is

placed in a compromised position may lead

to difficulties with abutment and crown

placement and hygiene. Therefore, good

extraction technique to preserve the

socket wall and interradicular bone is vital

to the successful outcome of immediate

implant placement after an extraction.

MAXILLARY SINUS BONE GRAFT Maxillary sinus bone graft (MSBG) was first

introduced by Tatum in 1976. 88

Subsequently, Boyne and James published

the first study of maxillary sinus bone

grafting using autogenous bone grafting in

1980. 89 Ever since then, a lateral window

approach, derived from the Caldwell-Luc

procedure, has been the surgical choice to

treat vertically deficient bone in the

posterior maxilla. 90-93 Even though

autogenous bone is the gold standard,

different bone grafting materials have

been used in the lateral approach MSBG

with predictable results. 94-100

The obvious indication for MSBG is

inadequate vertical alveolar bone in the

posterior maxilla for implant placement. As

long as the bone grafting does not extend

to block the ostium, bone grafting in the

sinus is not contraindicated and is

generally a benign

procedure. 101 Contraindications for MSBG

can be categorized into two groups:

patient (medical) and sinus (local)

factors. 101, 102 Some of the patient or

medical contraindications include

chemotherapy or radiotherapy of the

maxillary region, immunocompromised

status, medical conditions affecting bone

metabolism, pregnancy, uncontrolled

diabetes and alcohol or drug abuse. Sinus

or local contraindications include

inadequate transverse dimension of the

sinus, intranasal acute or chronic sinusitis,

unrepaired oroantral fistula, recent nasal

or sinus surgery, cysts or tumors of the

sinus, and ostium in the surgical site.

In addition to these contraindications,

there are factors that may predispose

certain patients to implant failures in the

maxillary sinus.101-104 One of the predictors

of implant failure in the posterior maxilla is

smoking. Studies have shown that

smoking is a relative risk to implant

failures. 105, 106 In regards to effects of

smoking in MSBG, a retrospective study by

Zinser104 evaluated 1,045 implants placed

in the grafted maxillary sinus and

concluded that smoking doubled the

relative risk of implant failure.104 In

contrast, a review of implants placed in

maxillary sinus lift sites by Pjetursson, et

al.107 did find higher failure rates for

smokers compared to non-smokers (3.5%

vs. 1.9 %, respectively), but this

difference was not statistically significant.

Other predictors of implant failure in the

posterior maxilla that were mentioned are

bone quality, time lapse from extraction to

implant placement, residual alveolar bone

height, augmented compared to non-

augmented sinus and membrane

thickness.

After Tatum88 first introduced lateral

approach MSBG, Summers 108 published

the first crestal approach (also known as

transalveolar) to the sinus, using a set of

tapered osteotomes with increasing

diameter. Since then, MSBG has evolved

over the years from lateral window

opening to various crestal approach

techniques, including using piezoelectric

surgery, trephines, osteotome, hydraulic

lift/pressure, press-fit bone block, drills

specifically designed for crestal approach

and modifications of these techniques.109-

121 Studies comparing crestal versus lateral

approaches to MSBG revealed that both

techniques showed similar success in

clinical results.122-124

The main advantages to the crestal

approach MSBG is that it can be done

without a flap, with less post-operative

swelling and pain, minimal bone grafting

materials and with reduced surgical

time.107,116,125 The most common crestal

approach MSBG technique is condensing

and tapping of the bone with various

diameter osteotomes to lift the sinus

membrane, which was first described by

Summers.108

The crestal approach is simpler than the

lateral approach MSBG in the immediately

extracted molar sites. This is due to the

fact that the unevenness of the maxillary

sinus floor often occurs from molar roots

protruding into the sinus, which can make

a lateral approach MSBG more challenging.

In addition, the lateral approach will

require making a buccal bony window

above the mesio-buccal and disto-buccal

roots (approximately 12 mm in length) and

continuously elevating the membrane

inferiorly to the sinus floor, at which the

lowest point is at the trifurcation of the

roots.80 These factors can make the lateral

approach sinus lifting more challenging

immediately after the extraction.

In the crestal approach MSBG in

immediately extracted molar sites, the

opening into the sinus is through the

interradicular bone, which is usually the

most inferior part of the sinus floor in the

maxillary molar. Elevating the membrane

from inferiorly to superiorly, will result in

uniform and “tent” like sinus

elevation.102Also, the crestal approach

sinus lift is completed after a sufficient

elevation and, thereby, reducing the

overall sinus lifting. Whereas in the lateral

approach, a much larger area of the sinus

has to be elevated due to the inability to

form “tent” like membrane elevation.

In addition, it is the author’s opinion that

better stability of the implant can be

achieved with a crestal approach due to

“tent” like lifting of the maxillary sinus

membrane. This “tenting” effect of the

maxillary sinus membrane, via crestal

approach, allows firmer condensing of the

bone grafting particles within the elevated

membrane space than the lateral

approach, which usually has a much larger

membrane elevated space that can allow

more movement of the bone grafting

particles.

In 2000, Cosci and Luccioli, 129 published a

study introducing a new sinus lift

technique with the use of lifting drills to

perforate, not fracture, the sinus floor and

lift the membrane. This technique is

referred to as the Cosci’s technique. The

tip is specially designed so that it will not

perforate the sinus membrane even if the

drill tip makes contact with the membrane.

There is no use of osteotomes. In this six

year retrospective study, 265 implants

were placed in a one stage crestal

approach MSBG, in healed sites, with eight

implant losses, resulting in a 97% survival

rate. One study even compared Cosci’s

technique to Summers’ technique.116 This

study showed that both techniques

displayed predictable results but Cosci’s

technique required less surgical time, less

intra- and postoperative morbidity and was

preferred by patients. In another study,

134 implants placed in a multicenter

retrospective study using Cosci’s

technique, showed implant survival rate of

96.3% with average follow-up time of 48.2

months.130In this study, the average pre-

operative alveolar bone height was 3.46

mm + 0.91 mm, which further shows that

implants can be successfully placed with

simultaneous crestal approach MSBG in

alveolar bone height of less than 5 mm.

INDICATIONS AND RATIONALE FOR IMMEDIATE MAXILLARY MOLAR IMPLANT PLACEMENT WITH SIMULTANEOUS CRESTAL APPROACH MAXILLARY SINUS BONE GRAFT AND FLAPLESS EXTRACTION Reduced vertical alveolar ridge due to

inherent bone remodeling is one of the

challenges of an implant placement after

the extraction of maxillary posterior

teeth.17,18 In addition to anatomic

limitations, maxillary sinus

pneumatization, which ends normally at

age 20, will continue to progress after the

extraction with loss of vertical alveolar

bone.94,131,132Clinicians should consider

preserving the alveolar bone height by

immediate implant placement and/or

immediate bone grafting to decrease the

sinus pneumatization and alveolar bone

loss.133 In addition, time lapse from the

extraction to implant placement is one of

the predictors of implant failure in

posterior maxilla.103

Immediately after the extraction the best

treatment for posterior maxillary teeth

may be an implant placement with

simultaneous MSBG, if indicated. In a

retrospective analysis, 391 implants were

placed immediately after the extraction of

maxillary molar teeth and 156 out of 391

implants required simultaneous MSBG due

to inadequate alveolar bone

height.86 Overall survival rate was 99.5%

(389/391) after 75 month follow-up,

showing that immediate maxillary molar

implant placement at the time of

extraction with simultaneous crestal

approach has a high survival rate.

One of the drawbacks for crestal approach,

as with the lateral approach, is achieving

adequate primary stability of the implant

at the time of MSBG. Most studies indicate

that less residual alveolar bone results in

increased implant failure rate. 101,126,

127Therefore, studies have shown that ideal

residual alveolar height, for immediate

implant placement with simultaneous

crestal approach MSBG, should be 5-6 mm

to achieve primary stability of the

implant.107,125 However, Gonzalez, et

al.,128 compared the success rate of

immediate implant placement with

simultaneous crestal approach MSBG, in

healed extraction sites, with residual

alveolar bone height of < 4 mm and > 4

mm, which showed 100% and 98.51%

success rates, respectively. Simultaneous

crestal approach MSBG and implant

placement can be achieved in vertical

alveolar bone of less than 5 mm with a

high success rate.

The requirements for maxillary molar

implant placement, immediately after the

flapless extraction, with simultaneous

crestal approach MSBG are: 1) adequate

horizontal dimension for diameter of

planned implant; 2) no major soft tissue

defect, such as buccal or lingual fistula; 3)

no oroantral communication (OAC) greater

than 3-5 mm after the extraction; 4) no

purulent discharge from socket and/or

maxillary sinus after the extraction; 5) no

major periapical and maxillary sinus

infection and/or pathology; 6) no more

than one alveolar wall defect; and 7) no

symptomatic maxillary sinusitis. If any of

the mentioned criteria are not met, the

implant should be placed in a delay

approach. Comprehensive pre-operative

clinical and radiographic evaluations to

select an ideal surgical candidate for this

technique are paramount to a successful

clinical outcome.

Pre-operative radiographic evaluation for

maxillary molar extraction should include

the following: 1) horizontal and vertical

dimensions of interradicular bone; 2)

evaluation of maxillary sinus, such as

infection, thickness of membrane and

pathology; 3) presence of periapical

radiolucency, such as bone loss, infection

and lesion; 4) presence of OAC; and 5)

evaluation of alveolar wall, such as wall

defect, thickness of buccal bone and

vertical and horizontal dimensions of the

socket wall. It is possible to perform the

surgery with a panoramic radiograph but a

cone beam CT (CBCT) is highly

recommended for pre-operative

radiographic evaluation.

(Figure 1A, B) Clinical evaluation for

maxillary molar should include the

following: 1) status of adjacent teeth; 2)

soft tissue evaluation (such as keratinized

tissue, gingival recession, swelling and

fistula); 3) inter-occlusal and mesio-distal

space; 4) clinical signs of parafunctional

habits; and 5) occlusion.

Figure 1A. Cone beam CT of maxillary molar tooth.

A. Maxillary molar tooth with divergent roots with adequate

interradicular bone for an immediate implant placement.

Sinus is within-normal-limit (WNL).

Figure 1B. Maxillary molar tooth with inadequate

interradicular bone for an immediate implant placement due

to convergent roots. Notice the roots are protruding into the

sinus. Sinus is WNL.

This technique is a preferred implant

treatment plan for many, if not all, of the

patients that desire an implant after the

extraction when they are given delayed vs.

immediate surgical options.

If the extraction, RPBG, MSBG, and

implant placement are done in 2 or more

surgeries, the patient may select a non-

implant treatment option, due to increased

treatment time, cost, and number of

surgeries, even though an implant may be

the best treatment option and the patient’s

preferred plan. The added benefit for the

surgeon is less operative procedures with

less office visits.

SURGICAL TECHNIQUE FOR IMMEDIATE MAXILLARY MOLAR IMPLANT PLACEMENT WITH SIMULTANEOUS MAXILLARY SINUS BONE GRAFT AND FLAPLESS EXTRACTION Pre-operative Regimen

The patient is given the following pre-

operative antibiotic regimen: 1) If the

patient has no allergic reaction to

penicillin, the patient takes 2 grams of

amoxicillin 1 hour prior to surgery and

then 1 gram bid for 5 days; 2) If allergic to

penicillin, the patient takes 600 mg

clindamycin 1 hour prior to surgery and

then 150 mg qid for 5 days. Just prior to

surgery, the patient’s mouth is rinsed with

chlorohexidine gluconate for approximately

15-20 seconds.

Flapless Extraction

As mentioned previously, the most

important aspect of the extraction is not

whether the flap is made, but rather that it

is focused on minimizing the removal of

bone. Therefore, the extraction technique

should concentrate on preserving the

alveolar bone, especially the buccal and

interradicular bone.

After local anesthetic is administered, the

first step is to gently free up the crestal

gingival tissue away from the tooth

without stripping off any of the periosteum

from the alveolar bone. To do this, a 2/4

molt curette (Hu-Friedy, Chicago, Ill.) is

placed into the gingival sulcus, including

the interdental gingival tissue. The soft

tissue is then gently pushed away from the

tooth. Freeing up the crestal gingival tissue

slightly allows for reduced trauma to the

soft tissue from any instruments that will

be in close contact during the extraction. A

periosteal elevator can also be used to free

up the crestal gingival tissue. No incision is

made and interdental papilla is not

detached from the bone during the

extraction.

Next, a periotome (Dowell, Rancho

Cucamonga, Calif.) is used to separate

buccal bone from mesiobuccal to

mesiodistal and palatal bone from the

trunk and root of the tooth. Use of a

periotome will reduce the incidence of

alveolar bone fracture and, more

importantly, can be used to preserve the

buccal bone in the socket, instead of

having the buccal bone attached to the

root during the extraction. Then a straight

elevator or slightly curved elevator is

placed into the sulcus to gently subluxate

the tooth. After adequate subluxation, if

there is enough tooth structure, an

attempt is made to extract the tooth by

using a modified upper forcep (Karl

Schumacher, Linden N.J.). Using a

modified forcep that has smaller and

narrower beaks will reduce trauma to the

alveolar bone and soft tissue, compared to

a conventional upper forcep.

During the extraction, with a forceps or

even with an elevator during subluxation,

the crown of the tooth can fracture,

leaving part of the crown, trunk or roots in

the socket. If part of the crown or trunk is

in the socket, it is sectioned to separate

the multi-rooted maxillary molar tooth into

multiple single roots.134The goal is to

section the multi-rooted maxillary molar

tooth and remove the roots individually.

However, during sectioning, be cognizant

to avoid removal of the buccal and

interradicular bone, which is located just

below the root trunk. Trunk length is

approximately 4 mm.15

Since maxillary molar teeth have 3 roots,

section the remaining crown or trunk into

3 parts: mesiobuccal, distobuccal and

palatal root.

(Figure 2) To accomplish this, a ½ or #2

round bur (SS White, Lakewood, N.J.) is

used with a surgical handpiece. During

trisecting of the roots, it is not necessary

to touch the bone with the round bur.

Preserving the interradicular bone is crucial

for an immediate implant placement

because this may be the only source of

bone for the primary stability of the

implant.

Figure 2. Multi-rooted maxillary molar tooth is sectioned

into 3 separate roots, mesio-buccal (MB), disto-buccal (DB)

and palatal (P) roots.

After trisecting the roots, a small elevator

or 2/4 molt curette can be used to

complete the separation of the roots and

then, using the same instrument,

subluxate and extract the roots. A thin

periotome or root tip pick can also be used

to loosen and remove the roots. If the

roots are firmly embedded in the socket

and difficult to extract, a ½ round bur can

be used to section the roots, mesio-distally

or bucco-lingually, and then remove the

sectioned roots using appropriate

instruments. All 3 roots can be removed in

this manner.

After extraction of the three roots, the

socket needs to be carefully examined for

any potential complications. The following

should be evaluated: sinus floor and

membrane, socket wall, interradicular

bone and presence of infection. If the sinus

floor is difficult to visualize, the Valsalva

maneuver can be gently performed to

check for oroantral communication. After a

thorough examination, the socket is gently

curetted to remove any granulation tissue

and periapical lesion. However, this step

should be done with caution if the sinus

membrane is exposed or perforated.

After careful curetting, thoroughly re-

evaluate the socket. Depending on the

clinical findings, the surgeon will decide at

this time whether or not to continue with

the next step, modify the treatment plan

or abort the surgery. Whether to continue,

modify, or abort the surgery will depend

upon several factors: 1) sinus membrane

perforation and size of perforation; 2)

vertical and horizontal dimensions of

interradicular bone; 3) size and location of

bony wall defect; and 4) presence and

extent of periapical and sinus infection.

Based on these factors and clinical

findings, the final decision will depend on

whether the alveolar ridge can be

preserved, the implant can attain primary

stability, and a sinus bone lift can be

predictably performed. If the decision is

made to continue with the surgery, the

next step is the crestal approach MSBG.

Crestal Approach to the MSBG

From the pre-operative CBCT and socket

evaluation, approximate vertical and

horizontal dimensions of the interradicular

bone are estimated. Ideal bucco-lingual

and mesio-distal position of the implant is

usually the mid-crest of the interradicular

bone. The author’s crestal approach

maxillary sinus bone grafting technique is

similar to the technique that was described

by Cosci and Luccioli,129 where “lifting”

drills are used to perforate the sinus floor

without perforating the sinus membrane.

The first drill used in the crestal approach

MSBG is a 1.3 mm pilot drill (Salvin,

Charlotte, N.C.) at 800 RPM, with copious

normal saline or sterile water irrigation.

The depth of the drilling is approximately

1-2 mm short of the estimated vertical

dimension of the interradicular bone.

During drilling with a pilot drill, the sudden

feel of denser bone may indicate that the

drilling depth is at or close to the sinus

floor, which is composed of cortical bone.

Cortical bone will feel denser compared to

medullary bone and the surgeon’s tactile

sensations should be able to differentiate

between cortical and medullary bone

during drilling. The next drill used is a 2.0

mm twist drill, again 1-2 mm shy of

estimated vertical length of the

interradicular bone. After each drilling

sequence, measure the depth of the drill

site with a depth gauge or probe. It is

important not to drill through the sinus

floor with the twist drill, as this will

increase the likelihood of sinus membrane

perforation. After using the 2.0 mm twist

drill, specially-designed crestal approach

sinus (CAS) drills (Hi-Ossen, Fairless Hills,

Pa.)

(Figure 3A, B) at 600-800 RPM will be

used to approach the sinus floor and enter

the maxillary sinus without perforating the

sinus membrane. These CAS drills come in

various diameters (2.8, 3.1, 3.3, 3.6, 3.8,

4.1 mm) and the drill tip is specially

designed to minimize sinus perforation

even if the tip of the drill touches the sinus

membrane.

Figure 3A. Crestal approach sinus drill (CAS drill). A. 4.1 mm

CAS drill.

Figure 3B. 4.1 mm CAS drill with a stopper.

To further reduce the chance of sinus

membrane perforation, drill stoppers are

used during the drilling sequence to better

visualize the depth of the drill, and to

prevent entering the sinus too quickly. Drill

stoppers come in various lengths and they

can be “snapped” into place at the junction

of the drill and shank. Stoppers come in

different lengths, in increments of 1 mm,

which will indicate the length of CAS drill

that will be entered into the drill site. A

stopper will hit the ridge and prevent the

drill from entering deeper once the

appropriate length is reached.

The first CAS drill used is a 2.8 mm with a

stopper that will give a slightly longer drill

length than the last measured drilled

depth. Then, sequential CAS drills with

increasing diameter and shorter stoppers,

to increase the length of the drill by

increments of 1 mm, are used until the

sinus floor is perforated. Drilling should be

done gently and slowly to minimize sinus

membrane perforation. In addition, all CAS

drills do not need to be utilized for every

case. During the drilling sequence, CAS

drills that are close in diameter can be

skipped, depending upon the “softness”

and amount of the bone present. As soon

as the sinus floor is felt, there should be a

sudden “soft” feel with no resistance.

After the sinus floor is felt, carefully

examine the site for any perforation of the

membrane. If a visual evaluation of the

sinus membrane cannot be achieved, the

Valsalva maneuver can be performed

gently to check for OAC. If the sinus

membrane is not perforated, the next step

is the hydraulic lifting of the membrane.

(Figure 4A, B) The purpose of this step is

to gently elevate the membrane using

sterile liquid, such as normal saline (NS),

which will reduce the risk of sinus

membrane perforation while elevating the

membrane.

Figure 4A. Hydraulic lifter.

A. A hydraulic lifter is used to elevate the sinus membrane.

Figure 4B. Using the hydraulic lifter, normal saline (NS) or

sterile water is injected into the sinus to elevate the

membrane.

The hydraulic lifting is done using a NS

filled 3 cc syringe that is connected to a

rubber hose, which also has a broader

rubber tip connected at the other end. The

broader rubber tip will be placed right up

against the crestal drill site and

approximately 0.5 – 1.0 cc of NS will be

slowly injected into the sinus cavity to

elevate the membrane. After injecting NS

into the sinus cavity, draw NS back into

the same syringe and then inject more NS

into the sinus cavity again, like a

“pumping” action. This step is done

multiple times to elevate the membrane

slowly. One of the drawbacks with this step

is that a significant amount of NS may leak

out because the rubber tip may not fit

tightly in the drilled implant site. This can

make it more challenging to hydraulically

lift the membrane. A best effort should be

made to lift the membrane up to or close

to the desired vertical length with

hydraulic lifting.

After hydraulic lifting, the bone carrier is

used to carry the bone grafting particles

into the crestal drill site. Then, push gently

into the sinus cavity with a bone

condenser. Adequate sinus bone grafting

can be verified with CBCT or a blunt-ended

depth gauge. After adequate MSBG, the

next step is implant placement.

Immediate Implant Placement

Horizontal and vertical dimensions of

interradicular bone will determine the

diameter and length of the last CAS drill to

be used, and thus, that of the implant that

will be placed. As mentioned previously, a

CBCT can give approximate dimensions of

the interradicular bone, which will

determine the approximate diameter of the

implant. However, the exact diameter of

the implant will be determined during

surgery. The last CAS drill will be

determined by dimensions of the

interradicular bone and should be at least

2-3 mm away from the buccal bone. This is

usually not a problem for molar sites since

the average bucco-lingual and mesio-distal

measurement is 10 mm.80 Generally, the

diameter of the implant that is placed in a

molar site is 4-5 mm, with 5 mm being the

most common, and the length is 10 -12

mm.

After bone grafting and attaining the

desired sinus elevation, the implant is

placed in a routine manner, just like it is

done in any other immediate implant

surgery. The final vertical position of the

implant is usually at or just below the crest

of the interradicular bone. If much of the

interradicular bone is missing or removed

during the extraction, the implant is placed

3-4 mm below the buccal gingival margin,

assuming primary stability of the implant

can be achieved and there is no significant

gingival recession and buccal bone loss.

Ridge Preservation Bone Graft

Due to dimensional changes after the

extraction, Ridge Preservation Bone Graft

(RPBG) is a routine procedure for all

immediate implant surgeries. After the

implant is placed into a final position, the

implant is covered with a cover screw,

cotton ball or sterilized

polytetrafluoroethylene (PTFE) tape (also

known as plumber’s tape) prior to bone

grafting in order to prevent bone grafting

particles falling inside of the implant. If all

the socket walls are intact, freeze-dried

cortico-cancellous mineralized allograft

(Osteokor, Surgikor, Calif.) is loosely

packed into the socket, even if the gap is

less than 2 mm. For any socket wall

defect, which is usually the buccal wall,

xenograft (Bio-Oss, Geistlich, N.J.) is

placed in the bony defect area and then

allograft is placed in the remaining socket

space. Bone grafting particles are placed

up to the fixture level and, after removing

the cover screw or material that is

covering the inside of the implant, the

healing abutment is then placed. The top

of the healing abutment should be at or

slightly above the gingival margin. One of

the main advantages of placing the healing

abutment is faster soft tissue healing

compared to primary closure.

After the healing abutment is placed,

additional bone grafting particles are

placed approximately 1-2 mm above the

implant fixature level. Resorbable collagen

membrane (Cytoplast, Osteogenic

Biomedical, Texas) is placed above any

exposed bone grafting particles. There is

no undermining of the soft tissue or

periosteum during placement of the

resorbable collagen membrane. Even

though an incision or flap was not made,

non-resorbable sutures (Cytoplast,

Osteogenic Biomedical, Texas) are placed

bucco-lingually to provide some gingival

tautness and to prevent the resorbable

membrane from coming out too early

during normal oral function and hygiene.

SURGICAL CASES Surgical Case 1

A 48-year-old male presents with failing

root canal treatment (RCT) and

unrestorable tooth #14. (Figure 5A-

C) Patient’s past medical history (PMH) is

non-contributory. Pre-operative clinical

evaluation showed a missing crown of

tooth #14, minimal gingival recession, and

severe buccal abrasions of adjacent teeth.

Adjacent teeth that show severe abrasions

will be restored with new restorations PFM

at a later time. Cone beam CT showed mild

thickening of the sinus membrane,

periapical infection with possible sinus floor

perforation and approximately 5-7 mm of

vertical length of the interradicular bone.

Figure 5A. Pre-operative periapical radiograph of tooth #14.

Figures 5B & C. Pre-operative clinical intra-oral views.

(Figure 5D-F) After treatment options

were discussed with the patient, the

chosen treatment plan was immediate

implant placement after the extraction,

with simultaneous MSBG.

Figure 5D. Pre-operative CBCT of MB root and

interradicular bone of tooth #14.

Figure 5E. Pre-operative CBCT of DB root and interradicular

bone of tooth #14

Figure 5F. Pre-operative CBCT of palatal root (PR) of tooth

#14. Slight thickening of the membrane is noted. From the

CBCT, estimated vertical length of the interradicular bone is

5-7 mm.

(Since the detailed description of the

surgical technique was outlined in one of

the previous sections, only the key points

of the surgery will be mentioned for

surgical cases.)

Since the crown was missing, tooth #14

was sectioned to extract the mesio-buccal,

disto-buccal and palatal roots separately

without making a flap.

(Figure 5G, H). Next, a pilot drill is used

to make the initial drill site, drilling about 1

mm short of estimated minimum vertical

dimension of the interradicular bone that

was measured in the CBCT. Then, a twist

drill (2.0 mm) is used to make the drill site

slightly wider and to drill up to the same

vertical depth as the pilot drill. Then, a 2.8

mm CAS drill, which is the narrowest CAS

drill diameter, with a 6 mm stopper will be

used to widen the drill site and to increase

the vertical depth, gradually getting closer

to the sinus floor.

Figure 5G. Without a flap, tooth is sectioned into 3 separate

roots, MB, DB and P roots.

Figure 5H. Roots are extracted one at a time. Interradicular

bone is preserved.

(Figure 5I, J) Sequential CAS drilling is followed with appropriate stoppers to increase the length of the drill, 1 mm incrementally, until the sinus floor is met. After each CAS drilling sequence, using a blunt ended instrument, the drill site is checked for sinus floor perforation, since the sinus floor can be partially perforated, such as in cases where the sinus floor is inclined or uneven.

Figure 5I. CAS drill with a stopper.

Figure 5J. The CAS drill with a stopper being used to

perforate the sinus floor.

After the sinus floor is met and the membrane is intact, a hydraulic lift is performed. Approximately 0.5 – 1.0 cc of NS is pushed into the sinus cavity to elevate the membrane. During hydraulic lifting, the goal is to lift the membrane superiorly as possible but not more than the desired vertical length. After hydraulic lifting, bone grafting particles are gently condensed into a space between the sinus floor and the membrane is lifted until the sinus membrane is adequately elevated.

(Figure 5 K,L) This can be verified with radiograph or a blunt ended measuring instrument.

Figure 5K. Bone carrier being used to place the bone grafting

materials into the elevated sinus membrane space.

Figure 5L. View of the implant site after bone grafting.

Notice that the implant site is within confines of the

interradicular bone.

After adequate sinus elevation, an implant (5 x 10 mm) is placed in the ideal position, which is at or just below the crest of the interradicular bone, or 3-4 mm below the buccal free gingival margin.

(Figure 5 M) A cover screw is placed and allograft bone particles are placed into the remaining socket space, similar to RPBG technique. The cover screw is then removed and the healing abutment is placed. Resorbable membrane is placed over the exposed bone grafting particles and non-resorbable sutures are placed in an interrupted manner.

Figure 5M. Implant (5 x 10 mm) is positioned in the

interradicular bone.

(Figure 5 N) Surgery was uneventful and there was no sinus membrane perforation. The sutures were removed in 1-2 weeks and patient is to follow-up for 5-6 months or until the implant is ready for abutment and final restoration.

Figure 5N. Clinical view immediately after surgery

(Figure 5O-V)

Figures 5O & P. Cone beam CT taken immediately after

surgery. Note the dome or tent shape of the elevated sinus.

Figures 5Q & R. Five month post-operative clinical views.

Figure 5S. Five month post-operative clinical view with

healing abutment removed.

Figure 5T. Five month post-operative periapical radiograph.

Figure 5U. Ten month post-operative periapical radiograph.

(Final restoration was placed six months post-operatively).

Figure 5V. Twenty month post-operative periapical

radiograph. Note the newly formed sinus floor above the

implant.

Surgical Case 2

A 36-year-old female presents with failing

RCT of tooth #14 with poor long term

prognosis.

(Figure 6A). Her PMH is non-contributory.

Clinical examination showed multiple

missing teeth, crowding of upper maxillary

teeth and normal gingival soft tissue

around tooth #14. Orthodontic treatment

option, along with other treatment options,

was discussed but the patient decided not

to go through with the orthodontic

treatment. Pre-operative CBCT showed

mild thickening of the sinus membrane

without any other lesions, and 3-7 mm of

vertical length of the interradicular bone.

Figure 6A. Pre-operative periapical radiograph of tooth #14.

(Figure 6B-D) After treatment options were discussed, the treatment plan chosen was immediate implant placement, after the extraction, with simultaneous MSBG. (The sequence of surgical steps and follow-up will be similar to the one described for Surgical Case 1.)

Figure 6B. Pre-operative CBCT of MB root of tooth #14.

Figure 6C. Pre-operative CBCT of DB root of tooth #14.

Figure 6D. Pre-operative CBCT of PR of tooth #14. Sinus membrane is slightly thickened. From the CBCT, estimated vertical length of the interradicular bone is 3-7 mm.

(Figure 6E-I) There was no sinus membrane perforation or complications during the surgery. The sutures were removed in 1-2 weeks and post-operative healing was uneventful.

Figure 6E. Fractured crown during an attempt to extract

with a forcep.

Figure 6F. Without a flap, tooth is sectioned into three

separate roots, MB, DB and P roots.

Figure 6G. View of the finished implant site after bone grafting. Note the implant site is within the confines of the interradicular bone.

Figure 6H. Photo taken immediately after surgery.

Figure 6I. CBCT taken immediately after surgery. Note the

dome or tent shape of the elevated sinus. (Implant dimension:

4.8 x 10 mm)

(Figure 6J-Q)

Figure 6J. Facial view one week post-operative. Note that the patient has no post-operative facial swelling.

Figures 6K & L. Clinical views five month post-operative.

Figure 6M. Clinical view eight months post-operative. Final

restoration was placed six months post-operatively.

Figure 6N. Eight month post-operative periapical

radiograph.

Figures 6O & P. Clinical views 18 months after surgery.

Figure 6Q. CBCT view 18 months after surgery.

Surgical Case 3

A 51-year-old male presents with retained root tips of tooth #2. (Figure 7A) The patient’s PMH is non-contributory. Clinical examination showed missing teeth #4 and 30, normal gingival soft tissue, and missing crown of tooth #2 with retained root tips.

Figure 7A. Pre-operative panoramic radiograph.

(Figure 7B, C) Pre-operative CBCT showed a thickened sinus membrane without any other sinus lesions, periapical radiolucency extending to the sinus cavity with sinus floor perforation, and 3-5 mm vertical measurement of the interradicular bone with resorption at the furcation.

Figures 7B & C. Pre-operative clinical view of tooth #2.

(Figure 7D-F) For this case, the major concerns were periapical lesion, and ability to achieve primary stability of the implant due to vertical interradicular bone loss. After the extraction, interradicular bone, sinus floor and membrane will need to be thoroughly evaluated.

Figure 7D. Pre-operative CBCT of MB root of tooth #2.

Notice the vertical bone resorption of the interradicular bone.

Figure 7E. Pre-operative CBCT of DB root of tooth #2. Notice

the thickening of the sinus membrane and perforation at the

apex of DB and palatal roots.

Figure 7F. Pre-operative CBCT of palatal root of tooth #2. From the CBCT, estimated vertical length of the interradicualr bone is 3-5 mm.

After treatment options were discussed

with the patient, the treatment plan

chosen was immediate implant placement,

after the extraction, with simultaneous

MSBG. (The sequence of surgical steps and

follow-up will be similar to the one

described for Surgical Case 1.)

(Figure 7G – L) After the extraction, the sinus floor was perforated but the membrane was intact. There was no sinus membrane perforation or complications during the surgery. The sutures were removed in 1-2 weeks and post-operative healing was uneventful.

Figure 7G. Roots extracted without a flap.

Figure 7H. Using the CAS drill with a stopper to perforate

the sinus floor.

Figure 7I. Use of a blunt-ended bone condenser to gently lift

the sinus membrane during bone grafting. Marking on the

bone condenser indicates that the sinus elevation is just

beyond 10 mm.

Figure 7J. Implant is positioned and the socket is filled with

bone grafting particles.

Figures 7K & L. Immediate post-operative clinical views.

Here, Gelfoam (Pfizer, New York, N.Y.) was placed over the

resorbable membrane. This was one of the earlier cases and,

currently, Gelfoam is no longer used.

(Figure 7M-R)

Figures 7M & N. Clinical views 10 months after the surgery.

Implant was ready in 5-6 months but the patient decided to

wait on the final restoration.

Figure 7O. Periapical radiograph with the final restoration

11 months after surgery.

Figures 7P & Q. Clinical view 21 months after surgery.

Figure 7R. CBCT taken 21 months after surgery.

CONCLUSION With a thorough pre-operative clinical and

radiographic evaluation, a maxillary molar

implant placement, immediately after the

extraction, with simultaneous maxillary

sinus bone grafting is a predictable

treatment modality with a successful

clinical outcome in an ideal situation, even

with pneumatized maxillary sinus.

Combining 4 proven surgical techniques

into one surgery will reduce the total

treatment time, and the number of

surgeries and is the treatment option

preferred by the patient who wants to

have an immediate implant placement

after a maxillary molar extraction.

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