The socket-shield technique: a critical literature review

REVIEW Open Access

The socket-shield technique: a criticalliterature reviewChristian Blaschke1* and Donald R. Schwass2

Abstract

Introduction: Dental implants have become a standard treatment in the replacement of missing teeth. After toothextraction and implant placement, resorption of buccal bundle bone can pose a significant complication with oftenvery negative cosmetic impacts. Studies have shown that if the dental root remains in the alveolar process, bundlebone resorption is very minimal. However, to date, the deliberate retention of roots to preserve bone has not beenroutinely used in dental implantology.

Material and methods: This study aims to collect and evaluate the present knowledge with regard to the socket-shield technique as described by Hurzeler et al. (J Clin Periodontol 37(9):855-62, 2010). A PubMed database search(www.ncbi.nlm.nih.gov/pubmed) was conducted to identify relevant publication.

Results: The initial database search returned 229 results. After screening the abstracts, 13 articles were downloadedand further scrutinised. Twelve studies were found to meet the inclusion and exclusion criteria.

Conclusion: Whilst the socket-shield technique potentially offers promising outcomes, reducing the need forinvasive bone grafts around implants in the aesthetic zone, clinical data to support this is very limited. The limiteddata available is compromised by a lack of well-designed prospective randomised controlled studies. The existingcase reports are of very limited scientific value. Retrospective studies exist in limited numbers but are ofinconsistent design. At this stage, it is unclear whether the socket-shield technique will provide a stable long-timeoutcome.

Keywords: Dental implants, Socket-shield, Root-membrane, Partial extraction, Bone preservation, Root submersion

IntroductionDental implants have become a standard treatment inthe replacement of missing teeth. Whilst initially dentalimplants were mainly used to secure complex multi-unitprostheses, in recent decades, it has become common toreplace single teeth, in particular in the aesthetic zone.Paired with the ever increasing demand to achieve cos-metically pleasing outcomes, this has led to the demandto preserve buccal hard and soft tissues. After tooth ex-traction and implant placement, resorption of buccalbundle bone can pose a significant complication withoften very negative cosmetic impacts. Hence, grafting

procedures are commonly carried out with the intentionof minimising loss of bundle bone. However, if it provedpossible to preserve bundle bone, these graft proceduresmight not be necessary. Studies have shown that if thedental root remains in the alveolar process, bundle boneresorption is very minimal. Knowing this, the techniqueof retaining roots has long been utilised for cases involv-ing removable prostheses, and to a lesser degree, fixedprostheses. However, to date, the deliberate retention ofroots to preserve bone has not been routinely used indental implantology. Back as early as 2010, Hurzeleret al. published a proof of concept proposing partialretention of tooth roots in an effort to preserve theimportant buccal bone. Preservation of bone and ossi-fication between residual roots and surrounding bone

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* Correspondence: [email protected] of Oral Diagnostic and Surgical Sciences, Faculty of Dentistry,University of Otago, 310 Great King Street, Dunedin, New ZealandFull list of author information is available at the end of the article

International Journal ofImplant Dentistry

Blaschke and Schwass International Journal of Implant Dentistry (2020) 6:52 https://doi.org/10.1186/s40729-020-00246-2

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http://www.ncbi.nlm.nih.gov/pubmed

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mailto:[email protected]

have been demonstrated in beagle dogs [1] (Fig. 1a–dhistology of socket-shield in beagle dogs).Hurzeler et al. postulated that leaving a 1.5-mm-thick

root fragment on the buccal aspect of the proposed im-plant site [1] would leave sufficient space for optimalplacement of the dental implant as well as maintain thebuccal plate.Figures 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 illustrate

the socket-shield technique as per Hurzeler et al.In addition to the beagle dog histology provided by Hur-

zeler [1], Schwimer et al. [2] provided human histologyshowing bone formation between the remaining dentin ofthe socket shield and the implant surface. Whilst this hist-ology was made possible due to a failed implant, it needsto be noted that this was an unintentional socket shield,and hence socket-shield dimensions as well as height re-duction might have been less than desirable with regard tothe here described socket-shield technique and thereforecontributed to the implant failure.This literature review examines the available evidence

regarding the socket-shield technique as postulated byProf. Hurzeler.A recently published systematic review [3] concluded

that modifications to the socket-shield technique as pos-tulated by recent studies was associated with promisingresults. Furthermore, it was stated that the choice ofgraft materials for socket-shield application did not playmuch of a role. However, data presented in the reviewby Mourya et al. does not seem to either confirm or

oppose this statement. Therefore this critical review wasconducted.

Material and methodsStudy procedure and materialThis study aims to collect and evaluate the presentknowledge with regard to the socket-shield technique asdescribed by Hurzeler et al. [1].The following inclusion and exclusion criteria were

applied:Inclusion criteria:

Studies including case reports investigating the socket-shield techniqueStudies published in EnglishStudies published between January 01, 1990, and May12, 2019

Exclusion criteria:

Animal studiesIn vitro studiesLiterature reviewsStudies published in languages other than English

Search strategyThis literature review was performed accordingly to thePRISMA 2009 checklist.

Fig. 1 a–d Histologies of Beagle dog socket shields

Blaschke and Schwass International Journal of Implant Dentistry (2020) 6:52 Page 2 of 17

Fig. 2 Socket-shield schematic, remaining root section(facial view) Fig. 3 Socket-shield schematic, remaining root section(transverse view)


A PubMed database search (www.ncbi.nlm.nih.gov/pubmed) was conducted to identify relevant publication.The following search term including Boolean opera-

tors was used:(dental AND ((implant OR implants) AND ((socket

shield OR socket-shield OR root membrane OR Huerze-ler OR partial extraction therapy))). This returned 288positive results, all abstracts were scrutinised, and arti-cles found to meet the inclusion and exclusion criteriawere downloaded for further investigation and screenedby both authors independently.Furthermore, the bibliographies of all downloaded articles

were screened manually to identify further relevant studies.In addition, a Google Scholar search with the identical

search phrase was conducted to identify further potentiallyrelevant articles. Studies found in addition to the PubMeddatabase search were labelled hand search (Fig. 14).

Data extractionData pertinent to the use of the socket-shield techniquewas extracted and entered into the master table (Table 1).

ResultsThe initial database search returned 229 results. Afterscreening the abstracts, 23 articles were downloaded andfurther scrutinised. Twelve studies were found to meetthe inclusion and exclusion criteria. The reference listswere further subjected to a hand search which returneda further 6 studies for this literature review (Fig. 14).The studies included are summarised in Table 1.

General overviewHurzeler et al. published the first article on the socket-shield technique [1]. Since then, the amount of publica-tions has steadily increased, with the largest number ofpublication in 2018 (Table 2). Most publications werecase reports; however, retrospective studies have beenpublished as early as 2014. Retrospective studies makeup the minority of data published (Table 3). Prospectivestudies have not been cited to date.

Type of publicationsThe majority of publications identified in this literaturereview were case reports (16/24) [1, 5–7, 9–11, 13–23,25–27]. Three publications were retrospective clinicaltrials/studies [8, 12, 24]; one publication was a rando-mised clinical trial [4].

Cohort sizeThe cohort size did vary considerably, whilst the majorityof case reports reported on single clinical cases up to 3cases. The three retrospective clinical trials did report on asmany as 128 cases followed up [12] and as little as 10 [8].Only one randomised clinical trial was identified in

this literature review [4] with a total of 40 implants in 40patients and a follow-up period of 36 months.

Observation timeThe observation time reported did vary considerably from0months up to 9 years [20]. The majority of publicationshowever did not state observation times past 1 year.

Fig. 4 Socket-shield schematic (transverse view)




OutcomeAll studies reported on osseointegration of implants andreported osseointegration rates comparable to traditionalplacement protocols. Generally, the case reports identi-fied in this literature review reported an osseointegrationrate of 100%. However, both referred to retrospectiveclinical trials (Gluckman et al. [12], Siormpas et al. [24])reporting significantly lower osseointegration rates of96.1% and 87.9%.The only randomised clinical trial (Bramanti et al. [4])

identified on the other hand reported 100% osseointe-gration; however, the cohort size was only 40 implantsfor both test and study group combined.Six studies did report additional to this regarding the

cosmetic outcome [8, 10, 12, 23].Several studies/case reports reported on the cosmetic

outcome of the implant treatment; however, the

cosmetic outcome was not consistently evaluated, onestudy used the pink aesthetic score, one study simplymentioned the positive outcome, and one studyemployed volumetric measurements to disciple theamount of tissue remodelling [25].

Preservation of buccal architecture/bone-heightAlmost all of the studies presented reported on the preser-vation of the alveolar ridge and/or soft tissue buccal to theimplant [1, 4, 5, 7, 8, 10–14, 16, 17, 19, 22, 23, 25, 26].However, the reporting was inconsistent with regard

to how this outcome was measured.Three studies analysed the volumetric changes by

means of 3-dimensional scans [7, 8, 23], one study evalu-ated the buccal bone by means of taking post-operativeCBCT scans [5], whereas others used the pink aestheticscore [4, 16], and finally, some studies did not specify

Fig. 5 Socket-shield in vivo (occlusal view)


Fig. 6 Implant placed palatally to socket shield

Fig. 7 a Healed implant site (occlusal view). b Healed implant site, emergence profile


Fig. 8 Preoperative tooth (facial view)

Fig. 9 Preoperative x-ray


how the outcome was measured at all [1, 10–14, 17, 19,22, 25, 26] and merely stated a good outcome wasachieved.

ComplicationsSix out of 18 studies reported on possible complicationswith the socket-shield technique [12, 13, 20, 23].The exposure (internal and/or external) of the socket

shield as reported by Gluckman et al. [12] was the mostcommonly reported complication pertinent to thesocket-shield technique with a total of 17 exposed socketshields reported. Gluckman et al. [12] reported 12 in-ternal and 4 external shield exposures. Two of the exter-nal exposures required a connective tissue graft to

achieve closure, and three infected socket shields re-quired removal of the socket shield altogether; however,the implants were able to be retained.The remaining complications reported were resorption

of the socket shield (2), peri-implantitis (2), non-integration of implants, or failed implant integration (7).

DiscussionThe majority of publications identified relating to thesocket-shield technique are clinical case reports and areunfortunately of little scientific value.Therefore, the “Discussion” section will mainly focus on

four clinical trials identified in the literature [4, 8, 12, 24]as well as publications by Hurzeler et al. [1] due to its

Fig. 10 Implant restoration in situ (facial view)

Fig. 11 Implant restoration in situ (occlusal view)


impact as proof of concept, and Mitsias et al. [18] andSchwimer et al. [2] as they represent the only available hu-man histologies to date.In general, cohort size in the clinical trials varied

significantly. Gluckman et al. [12] reported a large co-hort of 128 implants followed up over a significantperiod of up to 9 years which has weighted influenceon the data presented in this literature review. Theremaining trials had very small cohorts and short ob-servation times.Hurzeler et al. [1] first reported the socket-shield

technique as a proof of concept in an animal model.Whilst they were able to demonstrate the formationof a bony layer between the socket shield and the im-plant surface through histological evaluation, the ani-mal model poses limitations when the technique istranslated to humans.

Mitsias et al. [18] and Schwimer et al. [2] demon-strated similar outcomes.The article by Bramanti et al. [4], whilst of small

cohort size and short observation period, constitutedthe only randomised clinical trial to date in literature.However the surgical protocol in this study did varyfrom the technique described by Hurzeler et al. [1] inso far as the implant preparation was performed withthe tooth root in place, which was split just prior toimplant placement. Bramanti et al. [4] furthermorewere the only study group concluding that bone graftin combination with the socket-shield technique ismandatory. This is in direct contrast to Hurzeleret al. [1] who concluded that an advantage of thesocket-shield technique would be the fact that bonegrafting with its cost and added complexity is notrequired.

Fig. 12 Postoperative x-ray at time of fitting of implantplacement


Fig. 13 Postoperative x-ray after osseointegration

Fig. 14 Flowchart search strategy


Table

1Includ

edstud

ies

nAutho

rTitle

Year

Stud

ytype

Npatients

n implants

Region

Aug

men

tatio

nObservatio

npe

riod

po radiog

raph

ysupp

lied

Follow-up

radiog

raph

ysupp

lied

Osseo

integration

rate

Com

plications

nsurvival

implants

Cosmetic

outcom

eResults/con

clusion

19Bram

anti,

etal.[4]

Postextractio

nde

ntalim

plantin

theaesthe

ticzone

,socket

shield

techniqu

eversus

conven

tional

protocol

2018

Rand

omised

controlled

trial

4040

13–23or

33–43

allograft

(cop

iOs)

36100%

Nil

100%

PAS

sign

ificantly

high

erin

testgrou

p

Sign

ificantlyhigh

erPA

Sand

lower

amou

ntof

crestalb

one

change

intestgrou

p

10Daryet

al.

[5]

Thesocket

shield

techniqu

eusing

bone

trep

hine

:acase

repo

rt

2015

Caserepo

rt1

Premolar

(maxilla)

0Not

repo

rted

Autho

rsconclude

that

socket-

shield

represen

tsaprom

ising

techniqu

eto

preserve

buccal

bone

23Arabb

iet

al.[6]

Socket

shield:a

case

repo

rt2019

Caserepo

rt1

2Teeth21

and11

No

Nil

No

No

100%

Not

recorded

n/a

Not

recorded

Autho

rsconclude

that

the

socket-shieldtechniqu

ehasno

ten

ough

clinicaldata

torecom-

men

dfordaily

practice

11Baum

eret

al.[7]

Thesocket-shield

techniqu

e:First

histolog

ical,clin-

icalandvolumetri-

calo

bservatio

nafterseparatio

nof

thebu

ccaltooth

segm

ent-apilot

stud

y

2013

Caserepo

rt1po

stIV

bispho

spho

nate

use

2Canine

(maxilla)

-Socket

shield

central

incisor

-No

socket

shield

No

Nil

No

No

Not

repo

rted

2Socket-shieldtechniqu

eis

techniqu

esensitive

andne

eds

formorescientificdata

Socket-shieldtechniqu

ecanstill

notbe

gene

rally

recommen

ded

forclinicians

indaily

practice.

Yettheob

served

results

are

prom

ising

12Baum

eret

al.[8]

Socket

shield

techniqu

efor

immed

iate

implant

placem

ent—

clinical,

radiog

raph

icand

volumetric

data

after5years

2017

Retrospe

ctive

clinicalstud

y10

(5male,5

female)

Unkno

wn

Unkno

wn

51to

63mon

ths

(mean51

mon

ths)

100%

Not

repo

rted

Volumetric

change

smeasured

bymeans

ofstl

comparison

Meanloss

ofbu

ccal

tissue−

/0.37±0.18

mm

avrmid

facial

recession−

.33±.23

mm

Meanloss

ofmarginal

bone

level

0.33

mm

±0.43

mm

(mesial)0.17

±0.36

mm

atdistal

Pink

aesthe

ticscoremean

12(11–14)

Autho

rsconclude

,scien

tific

eviden

celacking,

socket

shield

sugg

estsadvantages

inim

med

iate

implantplacem

ent,

low

morbidity

andfavourable

cost-ben

efitratio

additio

nally

might

providemorepred

ictable

aesthe

ticou

tcom

ein

complex

cases

Furthe

rresearch

requ

iredfor

long

-term

stability

5Che

reland

Etienn

e[9]

Thesocket-shield

techniqu

eandim

-med

iate

implant

placem

ent

2013

Caserepo

rt1

2Cen

tral

incisors

Bio-Oss

6mon

ths

post

restoration

No

1mon

thpo

strestoration

6mon

ths

post

restoration

Not

repo

rted

2PA

atfollow-upshow

sno

inter-

pret

bone

change

4Dayakar

Immed

iate

2018

Caserepo

rt1

1Unkno

wn

3mon

ths

Yes

pa2mon

ths

Not

repo

rted

1Autho

rsconclude

that

SS-


Table

1Includ

edstud

ies(Con

tinued)

nAutho

rTitle

Year

Stud

ytype

Npatients

n implants

Region

Aug

men

tatio

nObservatio

npe

riod

po radiog

raph

ysupp

lied

Follow-up

radiog

raph

ysupp

lied

Osseo

integration

rate

Com

plications

nsurvival

implants

Cosmetic

outcom

eResults/con

clusion

etal.[10]

implantcombine

dwith

mod

ified

socket-shieldtech-

niqu

e:acase

letter

techniqu

eissuccessful

inpre-

servingof

tissue

24Dayakar

etal.[10]

Thesocket-shield

techniqu

eandim

-med

iate

implant

placem

ent

2018

Caserepo

rt1

1Tooth22

No

Nil

No

No

100%

Nil

n/a

Not

recorded

Autho

rsconclude

that

socket-

shield

techniqu

eshow

sprom

is-

ingresult

25Glocker

etal.[11]

Ridg

epreservatio

nwith

mod

ified

“socket-

shield”techniqu

e:ametho

dological

case

series

2014

Caserepo

rt3

313

(2)2

2(1)

Yes(Bio-Oss)

(2)fgg

(1)

Nil

Yes

No

100%

Not

repo

rted

n/a

Not

recorded

Autho

rsconclude

that

the

socket-shieldtechniqu

eisa

cost-effectivetechniqu

ewhich

avoids

resorptio

nof

bund

lebo

ne

13Gluckman

etal.[12]

Aretrospe

ctive

evaluatio

nof

128

socket-shield

casesin

thees-

theticzone

and

posteriorsites:

partialextraction

therapywith

upto

4yearsfollow-

up

2018

Retrospe

ctive

stud

yUnkno

wn

128

Num

erou

sUnkno

wn

1–4years

nana

123/128(96.1%

)5im

plant

failures,

reason

unknow

n3infected

socket

shields

+mob

ileremovalof

socket

shield,

retentionof

implant

2socket

shields

mob

ile,

removalof

socket

shield

andim

plant

12internal

socket

shield

expo

sures

4external

(oralcavity)

expo

suresof

socket

shields

2/4external

expo

sures

requ

iredctg

1socket

shield

migratio

n

123

Autho

rno

tedthat

nodark

hues

orrecession

expo

sing

the

abutmen

tto

fixture

interface

wereno

ted

Similarosseointeg

ratio

nrate

comparedto

tradition

altreatm

entconcep

t,with

the

adde

dbe

nefit

ofaless

invasive

approach.M

ostcommon

complication—

internal

expo

sure

ofsocket

shield—

conclusion

that

thess

was

not

redu

ceden

ough

toallfor

adeq

uate

space,furthe

rmore

authorsno

wrecommen

dthess

redu

ctionto

bone

level

18Gluckman

etal.[13]

Thepo

ntic-shield:

partialextraction

therapyforrid

gepreservatio

nand

pointedsite

developm

ent.

2016

Caserepo

rt10

14Anterior

maxilla

ctg,

xeno

graft,

fgc

12–18

mon

ths

1socket

shield

expo

sure

Subjectiveob

servationno

ticed

tissuevolumeto

bepreserved

1patient

hadcomplications—

all3

socket

shieldsexpo

sed

dueto

failure

ofsofttissue

closure

Autho

rsno

tethat

limited

scientificeviden

ceforthis

techniqu

eno

men

clatureis

notedas

beinginconsistent

Autho

rsno

tethat

additio

nal

research

andscrutin

yisne

eded

tovalidatethistechniqu

efor

usein

daily

clinicalpractice

21Guo

etal.

Tissue

2018

Casestud

y1

1Tooth21

Yes—

PRF

18mon

ths

Yes

Yes

100%

Non

e1

Stablesoft

Thesocket-shieldwas

effective


Table

1Includ

edstud

ies(Con

tinued)

nAutho

rTitle

Year

Stud

ytype

Npatients

n implants

Region

Aug

men

tatio

nObservatio

npe

riod

po radiog

raph

ysupp

lied

Follow-up

radiog

raph

ysupp

lied

Osseo

integration

rate

Com

plications

nsurvival

implants

Cosmetic

outcom

eResults/con

clusion

[14]

preservatio

nthroug

hsocket-

shield

techniqu

eandplatelet-rich

fibrin

inim

med

i-ateim

plant

placem

ent

tissue

repo

rted

inpreserving

thepe

ri-im

plant

tissueandcontou

r

20Han

etal.

[15]

Themod

ified

socket

shield

techniqu

e

2018

Clinicaltrial

3040

Prem

olar,

canine

and

incisorsin

mandible

and

maxilla

No

1year

pon/a

n/a

100%

Non

e40

Not

supp

lied

Autho

rsconclude

that

the

socket

shield

techniqu

eissafe

andefficient

inpreserving

bone

3Huang

etal.[16]

Theroot

mem

brane

techniqu

e:hu

man

histolog

iceviden

ceafter5

yearsof

functio

n

2017

Caserepo

rt1

1Bio-Oss

9mon

ths

cbct

Not

repo

rted

1Score13

14Hurzeler

etal.[1]

Thesocket-shield

techniqu

e:a

proo

f-of-p

rinciple

repo

rt

2010

Proo

fof

concep

t/case

repo

rt

11

Cen

tral

incisor

maxilla

Emdo

gain

0No

No

Not

repo

rted

Autho

rconclude

sthat

thiscase

repo

rtsupp

ortssocket

shields

asaviableim

plantplacem

ent

concep

t.Thistechniqu

epo

tentially

couldbe

used

toredu

cetheriskof

resorptio

nof

thebu

ndlebo

nepo

stextractio

n.

6Kanet

al.

[17]

Proxim

alsocket

shield

for

interplant

papilla

preservatio

nin

theaesthe

ticzone

2014

Caserepo

rt1

1Cen

tral

incisor

Bio-Oss

+pu

ros

(allograft)CTG

1year

post

restoration

Yes

pa1year

Not

repo

rted

1Autho

rsrepo

rtsatisfactory

aesthe

ticresult,bu

tthat

the

socket

shield

isatechniqu

esensitive

proced

urewith

limited

long

-term

eviden

ce

2Mitsias

etal.[18]

Clinicalbe

nefitsof

immed

iate

implantsocket

shield

techniqu

e

2017

Caserepo

rt1

1Non

e5years

Not

repo

rted

1Bu

ccalbo

neplatewas

maintaine

d,no

eviden

ceor

resorptio

napicalandmed

ial

partbe

tweensocket

shield

and

implantwas

filledwith

mature

bone

coronalp

artthat

was

conn

ectivetissue

16Mitsias

etal.[19]

Astep

-by-step

de-

scrip

tionof

PDL-

med

iatedrid

gepreservatio

nfor

immed

iate

im-

plantrehabilita-

tionin

the

estheticregion

2015

Caserepo

rt1

1Cen

tral

incisor

maxilla

Not

stated

3years

Yes

Yes

Non

e1

Noveltechniqu

esimilarto

the

socket

shield

techniqu

e(differen

ceisthedirect

implant

toroot

fragm

entcontact)

Autho

rsrepo

rtthat

this

techniqu

emight

preven

tpsycho

logicalimplications

oftoothextractio

n(as

partof

root

remains);ho

wever,a

carefulcaseselectionis

recommen

ded

17Szmukler-

Mon

cler

etal.[20]

Uncon

ventional

implant

placem

entpartIII:

implant

placem

ent

encroaching

residu

alroots—

a

2014

Caserepo

rt6

6Molars

mandible,

prem

olars

maxilla

and

mandible,

central

Not

stated

3–9years

Yes

Yes

6/6

1case

possible

resorptio

nof

tooth

fragm

ent

1im

plant

with

crestal

5–1

patient

drop

out

Autho

rrepo

rtsthat

the

presen

ceor

absenceof

root-

fillingmaterialseemed

tohave

noeffect

onim

planton

outcom

e


Table

1Includ

edstud

ies(Con

tinued)

nAutho

rTitle

Year

Stud

ytype

Npatients

n implants

Region

Aug

men

tatio

nObservatio

npe

riod

po radiog

raph

ysupp

lied

Follow-up

radiog

raph

ysupp

lied

Osseo

integration

rate

Com

plications

nsurvival

implants

Cosmetic

outcom

eResults/con

clusion

repo

rtof

6cases

incisor

maxilla

bone

loss

tosecond

/third

thread

9years

post

restoration

7Nevins

etal.[21]

Late

dental

implantfailure

associated

with

retained

root

fragm

ents:case

repo

rtwith

histolog

icand

SEM

analysis

2018

Caserepo

rt2

21stmolars

Case1:bio-

Oss

Case2:

DFD

BA

Case1:8+

years

Case2:4

years

Case1:yes

Case2:yes

Yes

Case1:

advanced

peri-

implantitis,

root

fragm

ent

attached

tomessiah

as-

pect

eviden

tCase2:loss

ofintegration

0Case1:Hum

anhistolog

y(LM)

revealed

implantin

bone

contactconsistent

with

osseointgration,

graft

biom

aterialincloseproxim

ityto

fixture,d

irect

implant

contactto

cemen

tum

ofthe

retained

root

surface,n

osign

ofpe

riodo

ntalligam

ent

Case2:LM

show

sbo

nein

betw

eenim

plantsurface

and

root

fragm

entlate

implant

failure

might

contrib

uteto

unintentionally

remaining

root

fragm

ents

1Po

uret

al.

[22]

2017

Caserepo

rt1

1Non

e3mon

ths

Not

repo

rted

1Autho

rsconclude

that

noadde

dcostforpatient,single

surgicalproced

ure,redu

ced

morbidity,p

ossibilityof

txin

patient

with

previous

end

patholog

ytutorsde

scrib

eas

favourabletechniqu

eforde

ntal

practice

8Schw

imer

etal.[2]

Hum

anhistolog

iceviden

ceof

new

bone

form

ation

and

osseointeg

ratio

nbe

tweenroot

dentin

(unp

lann

edsocket-shield)

and

dentalim

plant:

case

repo

rt

2018

Caserepo

rt1

1Premolar

Unkno

wn

2years

No

No

Loss

ofintegration

peri-

implantitis

0Autho

rsrepo

rted

failed

osseointeg

ratio

n2yearspo

strestoration,

human

histolog

yrevealed

root

fragm

ent

attached

toim

plant,bo

neform

ationon

implantsurface

eviden

tabsenceof

fibrovascular

tissue.

15Siormpas

etal.[23]

Immed

iate

implant

placem

entin

the

estheticzone

utilizing

the“roo

t-mem

brane”

techniqu

e:clinical

results

upto

5yearspo

stloading

2014

Retrospe

ctive

case

series

46(20male26

female)

46Anterior

maxilla

Nil

24–60

mon

ths

(mean40

mon

ths(

nana

100%

1case

resorptio

nof

root

fragm

ent

46Pre-,p

ost-op

erativecbct

in4

caseswith

maintaine

dbu

ccal

bone

volumein

3/4cases

Autho

rconclude

dthat

similar

complicationrate

totradition

alplacem

entprotocol

but

minim

isingof

facialbo

nevolumechange

sAutho

rconclude

sbo

nevolume

hasremaine

dstable;how

ever,

volumetric

investigationusing

cbct

data

was

onlycarriedou

tin

4/46

cases.

22Siormpas

etal.[24]

Theroot

mem

brane

techniqu

e:a

retrospe

ctive

clinicalstud

ywith

upto

10yearsof

follow-up

2018

Retrospe

ctive

clinicalstud

y182

250

Anterior

No

Mean49

mon

ths

n/a

n/a

Not

supp

lied

Not

repo

rted

5(87.9%

)Not

recorded

Autho

rrepo

rtssimilarsuccess

rate

asin

conven

tional

immed

iate

implants


Table

1Includ

edstud

ies(Con

tinued)

nAutho

rTitle

Year

Stud

ytype

Npatients

n implants

Region

Aug

men

tatio

nObservatio

npe

riod

po radiog

raph

ysupp

lied

Follow-up

radiog

raph

ysupp

lied

Osseo

integration

rate

Com

plications

nsurvival

implants

Cosmetic

outcom

eResults/con

clusion

9Wadhw

ani

etal.[25]

Socket

shield

techniqu

e:ane

wconcep

tof

ridge

preservatio

n

2015

Caserepo

rt1

1Cen

tral

incisor

Yes,material

unspecified

0Yes

No

Unkno

wn

Unkno

wn

Unkno

wn

Autho

rsconclude

that

thiscase

repo

rtsugg

estalveolar

bone

preservatio

n


With regard to clinical evaluation of the socket-shieldtechnique, only Baumer et al. [8] reported on volumetricchanges affecting the buccal tissues complex. Siormpaset al. [23] evaluated radiographic changes affecting theremaining root fragment, whilst Gluckman et al. [12] fo-cused exclusively on clinical complications.Bramanti et al. [4] did report the pink aesthetic

score.Therefore, inconsistent use of reporting measures

across the studies severely limited comparison of results.Surprisingly, as the vast majority of socket-shield im-

plants reported placed were in the cosmetic zone, use ofa relevant and consistent method of evaluation such as apink aesthetic score, or more preferably determinationof volumetric changes, was found to be rare.The study by Baumer et al. [8], which was the only

study to evaluate volumetric changes, reported onlysubtle facial tissue changes when compared to con-ventional immediate implant placement and restor-ation techniques.Whilst their results were encouraging and showed

similar, if not superior outcomes to conventional treat-ment protocols, the small cohort size limits what conclu-sions can be drawn.Siormpas et al. [23] on the other hand used radio-

graphs exclusively to assess bone changes following im-plant placement. Consequently, assessment was limitedto a 2-dimensional analysis of space changes. Given thatthe rationale behind the socket-shield technique is topreserve buccal volume after implant placement, andthat this is not discernible from conventional two-dimensional radiographs, this manuscript provides verylimited evidence supporting the technique.

Gluckman et al. [12] reported low complication rates;the most common adverse outcome reported was theexposure of the root fragment either internally ( towardsthe implant restoration) or externally (exposure towardsthe buccal soft tissue). The authors reported that neitherof these complications were difficult to manage orcaused an adverse aesthetic outcome.

ConclusionWhilst the socket-shield technique potentially offerspromising outcomes, reducing the need for invasivebone grafts around implants in the aesthetic zone,clinical data to support this is very limited. The lim-ited data available is compromised by a lack of well-designed prospective randomised controlled studies.The existing case reports are of very limited scientificvalue. Retrospective studies exist in limited numbersbut are of inconsistent design. At this stage, it is un-clear whether the socket-shield technique will providea stable long-time outcome.Hence, caution is advised at this stage when using the

socket-shield technique in routine dental practice. Clini-cians are advised to exercise best clinical judgementwhen considering to use the socket-shield technique fortreatment.Further clinical studies, preferably prospective rando-

mised controlled clinical trials involving power analysisto determine an adequate cohort size to inform statis-tical interpretation which would allow conclusions to bedrawn, are desirable.

AcknowledgementsAll illustrations courtesy of Prof M. Hurzeler, Munich, Germany.

Authors’ contributionsMain body and literature research was done by Dr Blaschke; article reviewand secondary input were done by Dr Schwass. The authors read andapproved the final manuscript.

FundingNo external funding for this article was received.

Availability of data and materialsThe dataset(s) supporting the conclusions of this article is available inPubMed.

Ethics approval and consent to participateNot applicable

Consent for publicationAll figures were supplied by Prof Hurzeler and consented for publication

Competing interestsDr. Christian Blachke and Dr. Donald Schwass declare no conflict of interest.

Author details1Department of Oral Diagnostic and Surgical Sciences, Faculty of Dentistry,University of Otago, 310 Great King Street, Dunedin, New Zealand. 2Facultyof Dentistry, University of Otago, 310 Great King Street, Dunedin, NewZealand.

Table 2 Publications on socket-shield technique

Year of publication n publications Case report/retrospective study

2010 1 1/0

2013 2 2/0

2014 3 2/1

2015 3 3/0

2016 1 1/0

2017 3 2/1

2018 4 3/1

Table 3 Study type of published studies

Study type n

Randomised clinical trial 1

Case report 20

Retrospective study 3

Clinical trial 1

Total 25


Received: 23 July 2019 Accepted: 29 July 2020

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The socket-shield technique: a critical literature review

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