Implant Bone Rings. One-StageThree-Dimensional Bone TransplantTechnique: A Case ReportMark R. Stevens, DDS1*Hany A. Emam, MS2

Mahmoud E. L. Alaily, MS3

Mohamed Sharawy, PhD4

A variety of techniques and materials has been used to provide the structural base of bone

and soft tissue support for dental implants. Alveolar bone augmentation techniques include

different surgical approaches such as guided bone regeneration, onlay grafting,

interpositional grafting, distraction osteogenesis, ridge splitting, and socket preservation. In

the case presented, a technique was used to augment the alveolar bone three-dimensionally

with autologous ‘‘bone rings’’ and immediate implant placement in a 1-stage procedure

following teeth extraction. Bone rings (circular osteotomies) were outlined at the symphysis

area using trephine burs, and a central osteotomy for implant placement was done before its

removal. The rings were then removed and sculptured to fit the extraction socket; this was

followed by screwing the implant through the ring, gaining its primary stability from the

prepared basal bone.

Key Words: trephine bone grafting, immediate implants, bone rings

INTRODUCTION

The definitive implant restoration

needs to be surrounded by hard

and soft tissue environment that

is in harmony with the surround-

ing dentition.1 The amount of

bone and soft tissue present prior to implant

surgery is the main issue but also the

precision in execution of the surgical tech-

niques should be considered to obtain an

overall favorable outcome.2

This article describes a surgical technique

of restoring maxillary incisors using immedi-

ate implants and autogenous bone graft in

the form of ‘‘bone rings’’ harvested from the

symphysis.

A 45-year-old woman presented with

persistent mobile maxillary central and

lateral incisors after definite periodontal

treatment (pocket depth ranged from 6 to

8 mm). The panoramic radiograph showed

moderate to severe bone loss around the

teeth. The patient underwent extensive full

* Corresponding author, e-mail: mastevens@mail.mcg.eduDOI: 10.1563/AAID-JOI-D-09-00029

1 School of Dentistry, Medical College of Georgia,Augusta, Ga.2 Oral and Maxillofacial Surgery, Faculty of Oral andDental Medicine, Cairo University, Egypt; MedicalCollege of Georgia, Augusta, Ga.3 Private practice, Cairo, Egypt.4 Oral Biology/Anatomy, Medical College of Georgia,Augusta, Ga.

CASE REPORT

Journal of Oral Implantology 69

mouth periodontal therapy including scal-

ing, root planing, and oral hygiene in-

structions to control her periodontal prob-

lem. The inflammatory condition stabilized;

however, mobility of the maxillary incisors

did not improve and temporary splinting

was not acceptable or predictable. Diagnos-

tic casts were mounted to visualize the

treatment plan for immediate implant place-

ment with simultaneous bone augmenta-

tion.

Surgical procedures

The patient was instructed to rinse with

0.12% chlorhexidine gluconate mouthwash

just prior to surgery for 1 minute. Surgery

was performed under deep conscious

sedation (Propofol) and local anesthesia

(articaine 4%, epinephrine 1:100 000) for

pain control. Preoperative antibiotic clin-

damycin, 600 mg, was administered intra-

venously.

Bone rings harvesting

The symphysis was accessed through a

genioplasty incision. The mental nerves were

exposed and protected. Using an 8-mm

trephine bur and under copious saline

irrigation, multiple circular osteotomies were

outlined, spaced, and drilled through the

exposed symphysis. The bone discs outline

were placed 3–4 mm away from the root

apices of the mandibular anterior teeth.

During this step, the trephine was slightly

torqued to partially loosen the bone discs to

facilitate its subsequent removal without

fracture. An implant drill was subsequently

used to prepare central osteotomies corre-

sponding to the final implant diameter to be

placed in the center of each disc converting

it to a ‘‘bone ring.’’ The osteotomies

corresponded to eventual placement of 3.0-

mm diameter implants. The ‘‘bone rings’’

were then carefully removed from the chin.

Four rings were harvested using the de-

scribed procedure (Figures 1 and 2).

Implant surgery

Gingival sulcular incisions were made

around the teeth to be extracted with 2

oblique vestibular releasing incisions. The

incisor teeth were extracted atraumatically.

Soft tissue remnants in the extraction

socket were carefully removed to ensure

complete removal of all contaminated

tissues. Sequential osteotomies through

the extraction sites were accomplished for

immediate implant placement as recom-

mended by the implant manufacturer. The

osteotomies were performed at least 3 mm

apical to the extraction socket as recom-

mended in the literature to obtain primary

stability. The bone rings were then used to

guide the pilot drill over the socket and

assist in their optimum prosthetic planned

positions.

The harvested bone rings were then

snuggly fitted in the extraction socket. Minor

contour adjustments were necessary to

ensure their adaptation and stability. Im-

plants were then tapped through the ‘‘bone

rings,’’ achieving and even increasing the

primary stability of ‘‘bone ring’’ and implant

to the basal alveolar bone. Countersinking of

the implants 1 mm was performed within

the bone rings to compensate for the

anticipated crestal bone resorption and

provide the best emergence profile by the

surrounding soft tissue drape.

Using a bone curette, scraping of

cancellous bone from the harvested site

was used to fill any observed gaps found

between the bone rings and the implant

preparation site. Concurrently, augmenta-

tion of facial defect was also accomplished

to further reconstruct the alveolar bone.

Sharp edges were identified and gently

rounded by low speed fissure bur under

copious saline irrigation. Periosteal scoring

was then accomplished at the base of the

flap to advance and expand the soft tissues

and provide primary closure without ten-

sion (Figures 3 and 4).

Immediate Implants and Bone Grafting

70 Vol. XXXVI/No. One/2010

A pressure bandage was applied to the

chin after layered closure and resuspension

of the mentalis muscle to provide continued

soft tissue support and to minimize postop-

erative edema.

Treatment outcome

All implants were osseointegrated. On in-

spection during the second phase surgery

(6 months), improvement in the overall

alveolar bone height and consequent soft

tissue level was achieved at the augmented

site. This was further supported by the

postoperative panoramic radiograph (Fig-

ures 5 and 6). No signs of infection or

dehiscence were noted around the implant’s

bone interface.

The patient showed complete satisfac-

tion with the final prosthesis with respect

to esthetics and function (Figures 7 through

9).

When placing an implant in an immedi-

ate extraction site, the surgeon needs to

consider the socket dimension and possible

gaps that occur around the coronal aspect of

the implant.3,4 One area that is overlooked or

difficult to simultaneously reconstruct is the

crestal bone height, especially after its loss

due to periodontitis.5,6 Another concern with

immediate implant placement with anterior

teeth sockets is the thin facial cortex of the

alveolar housing. This residual bone can

rapidly resorb or dehisce, compromising

the implant.7,8

There are several advantages proposed

by this technique, including a 3-D augmen-

tation of the native alveolar ridge, elimina-

tion of the socket gap implants interface,

and the ability to provide additional stability

of the implant at the crestal region of the

implant. The additional stability is achieved

through screwing the implants to the bone

FIGURES 1–4. FIGURE 1. Bone rings outlined in the symphysis with the central osteotomies correspondingto the diameter for implants to be placed. FIGURE 2. Bone rings after removal from the symphysis.FIGURE 3. Three dimensional augmentation using ‘‘bone rings’’ with simultaneous implant placement.FIGURE 4. Diagrammatic representation of the ‘‘bone ring’’ technique.

Stevens et al

Journal of Oral Implantology 71

rings, which are carpentered to fit snuggly

into the socket walls. This technique is also

advantageous in cases where there is insuf-

ficient primary implant stability secondary to

insufficient bone volume at the apical aspect

of the extraction site, and subsequent apical

drilling is not possible.

The simultaneous onlay crestal augmen-

tation by the ‘‘bone rings’’ at the residual

socket also enhances the soft tissue contour

and helps resist soft tissue contraction in this

highly esthetic zone. The ‘‘harvested’’ bone

rings ‘‘can be carved to any desired dimen-

sions, thus ideally reconstructing any alveo-

lar defect to optimize the biomechanical and

esthetic outcome. The implant also symbiot-

ically provides stabilization of the bone graft

to promote graft union and minimize graft

resorption.

Considering the treatment and healing

time, rather than performing 2 surgeries for

socket augmentation, waiting for graft heal-

ing, and reopening for implant placement, a

1-stage procedure for augmentation with

simultaneous implant placement can be

done in an acceptable operative time.9,10

This also will prevent further bone resorption

and soft tissue shrinkage with subsequent

loss of attached gingiva due to a second

surgery if a staged procedure is used.

Clinical reports have suggested that a

history of periodontal or endodontic infec-

tions is a predictive marker for implant

infection and failure. This clinical experience

FIGURES 5 AND 6. FIGURE 5. Preoperative panoramic radiograph (left) showing marked bone resorptionaround maxillary incisors. Periapical radiograph (right) showing preoperative crestal bone level.FIGURE 6. Postoperative (6 months) panoramic radiograph (left) showing the increased crestal boneheight gained by the ‘‘bone rings’’ around the implant (yellow arrows). Note the sites of the bone ringsharvested from the symphysis (white arrows). Periapical radiograph (right), showing bone surroundingthe cervical part of the implants (arrows). Note the integration of the bone rings with the crestal boneand the cervical part of the implants.

Immediate Implants and Bone Grafting

72 Vol. XXXVI/No. One/2010

has led most clinicians to avoid the imme-

diate implant placement at infected sites and

to consider infection as a contraindication

for immediate placement. However, the

present case report was performed in

accordance with a study made by Casap et

al11 who concluded that successful immedi-

ate implantation in infected alveoli can be

obtained, depending on complete removal

of all contaminated tissues and controlled

regeneration of the alveolar defect.

With the aid of advanced radiographic

techniques (computed tomography) for pre-

operative bony assessment and by using

graded trephine burs with different sizes, it is

possible to exactly harvest a precise pre-

calculated height and diameter bone graft

needed to augment the extraction socket

with simultaneous implant placement in the

optimum 3-D position.12 Also, in restoring

multiple missing adjacent teeth, an exact

width of the needed bone rings can be

predetermined in the treatment plan and

can be harvested in an exact dimension from

the chin providing a precise custom-made

augmentation at the desired area.

It should be mentioned that proper

preoperative treatment planning is manda-

tory in order to obtain favorable results.

During the grafting procedure, vertical and

horizontal measurements of the socket

defects were obtained to provide a 3-D

review for both bone ring graft dimensions

and to assist in implant emergence profile.

Care should be taken during bone rings

harvesting from the symphysis because

they may fracture during removal. It is

prudent to map out planned areas should it

be necessary to harvest additional bone

rings. Autogenous bone, which is still

considered the gold standard, is accompa-

nied by the usual donor site morbidities,

such as pain, edema, infection, and occa-

sionally paresthesia.

FIGURES 7–9. FIGURE 7. Probe denoting facial bone level aspect after periodontal depth measurement.FIGURE 8. Abutment placement. FIGURE 9. Final restoration.

Stevens et al

Journal of Oral Implantology 73

The patient was closely monitored clini-

cally and radiographically once a week for 1

month to ensure proper healing. Possible

early complications include dehiscence, graft

exposure, and infection. Late complications

include graft resorption, implant mobility,

and failure. In the present case, minor bone

changes were compensated by adding to

the crown length (limited cervical collar)

without compromising the biomechanics.

The patient was strongly encouraged to

maintain oral hygiene measures with chlor-

hexidine mouthwash and was maintained for

5 days on antibiotics (clindamycin 300 mg/

8 hours) to minimize the risk of infection.

Brufen, 400 mg/8 hours, was used for pain

control. Temporary prosthesis was kept out

of occlusion, and the underside of the bridge

was also relieved to avoid any pressure on

the surgical site during the healing period.

In conclusion, the proposed technique

offers multiple advantages of a 1-stage

procedure for immediate implant placement

and 3-D bone augmentation. Proper treat-

ment planning and careful surgical execution

are essential to ensure predictability.

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