SOCKET PRESERVATION- “HEALER OF THE

EMPTY SOCKET”- AN OVERVIEW

Dr.Dhwani. K .Dedhia, Dr.Vijayalakshmi.R, Dr.Jaideep Mahendra, Dr. Burnice Nalina Kumari.C

Department of Periodontology, Faculty of Dentistry,

Meenakshi Academy of Higher Education and Research Institute, Chennai, Tamil Nadu, India.

JIDAM

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ABSTRACT

Extraction is indicated when a tooth cannot be restored or

maintained in acceptable conditions for function and/or esthetics.

Following tooth extraction, alveolar bone loss and structural and

compositional changes of the covering soft tissues, as well as

morphological alterations takes place. The repair process results

in marked changes in the height and width of the alveolar

ridge with an average of 0.7-1.5mm of vertical and 4.0-4.5mm

of horizontal bone resorption which may lead to difficulties at

the time of implant placement. This lead to a technique called

‘Socket Preservation’, also known as alveolar ridge preservation.

This procedure reduces bone loss after tooth extraction to

preserve the tooth socket in the alveolar bone. The goal of

socket preservation is maintenance or enhancement of facial,

interproximal gingival contours and height of interproximal

papilla. Various materials and procedures are used for socket

preservation. Some of them are: connective tissue grafts, free

gingival graft, biocol, alloderm, prosthetic “pontic” socket plug,

autologous fibrin concentrates, GTR membranes and bone graft

materials like autografts, allografts, xenografts and alloplast.

Thus, socket preservation at the time of extraction is one of

the most significant procedures in the periodontal paradigm for

maintenance of health, youth and beauty.

KEYWORDS:

Socket preservation, Extraction sockets,

Alveolar bone remodeling, GTR, GBR.

JIDAM/Chennai/Volume:7/Issue:2/Pages 50 - 57/April-Jun 2020

Address for correspondence:

Dr.Vijayalakshmi.R, MDS
Associate Professor,
Department of Periodontology,
Faculty of Dentistry,
Meenakshi Academy of Higher Education
and Research Institute,
Chennai, Tamil Nadu, India.
Email id: rajaramvijayalakshmi@gmail.com

Received

: 18.05.2020

Accepted

: 05.06.2020

Published

: 27.06.2020

REVIEW ARTICLE

JIDAM/Chennai/Volume:7/Issue:2/Pages 50 - 57/April-Jun 2020

Dhwani et al: An overview of Socket Preservation

INTRODUCTION:

The periodontium includes gingiva,

connective tissue, cementum, periodontal ligament

and alveolar bone. The alveolar bone consists of

cortical bone, cancellous trabeculae, and the alveolar

bone proper. After the extraction of teeth, there is

resorption of the alveolar ridge resulting in its loss

of height and width, creating a potential esthetic

problem for prosthetic or implant dentistry. The

severity of the healing pattern of the extraction socket

may pose a problem for the clinician in 2 ways: it

creates an esthetic problem in the fabrication of an

implant-supported restoration or a conventional

prosthesis; and it may make the placement of an

implant challenging if not unfeasible. An average of

40% - 60% of original height and width is expected

to be lost after tooth extraction with the greatest loss

happening within the first two years.

What is Socket Preservation ?

The challenge for the dentist is to preserve

the quantity and quality of the gingival and osseous

tissues lead to the evolution of Socket preservation

or alveolar ridge preservation (ARP) (Fig 1). It is a

procedure to reduce bone loss after tooth extraction

to preserve the dental alveolus in the alveolar bone.

It was first described by Greenstein and Ashman

and Bruins in 1985. The term socket preservation

was first coined by Cohen in 1988 for a procedure

designed for prosthetic socket maintenance, ridge

preservation and ridge augmentation.

Fig 1: Socket Preservation

CLASSIFICATION:

According to Elian et al

(Fig 2)

• Type I socket: The facial soft tissue and buccal

plate of bone are at normal levels in relation to

the cementoenamel junction of the pre-extracted

tooth and remain intact post-extraction. Easiest

and most predictable to treat.

• Type II socket: Facial soft tissue is present but

the buccal plate is partially missing following

extraction of the tooth. They are most difficult

to diagnose.

• Type III socket: The facial soft tissue and the

buccal plate of bone are both markedly reduced

after tooth extraction. They are very difficult to

treat and require soft tissue augmentation with

grafts in a staged approach to rebuild lost tissue.

Fig 2: Elian classification of sockets

Chaar et al classification

This classification of extraction sockets

focuses on the bone topography of the extraction

socket. The protocol for treatment of each socket type

takes into account the shape of the remaining bone,

the biotype and the location of the socket whether it

be in the mandible or maxilla (Box1).

Box 1 : Classification and Treatment Protocol

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Dhwani et al: An overview of Socket Preservation

Grade I:

Grade I sockets are most ideal. It had an

intact buccal plate, adequate interproximal bone and

satisfactory apical topography. There is an intact

buccal plate having no fissures or dehiscence and

less than 25% loss of height (Fig 3).

Fig 3: Chaar classification of socket

Grade II:

Grade II sockets are differentiated from Grade

I by the amount and quality of the remaining buccal

plate. A grade II socket has a fissure, dehiscence, or

deficiency of the buccal plate totalling a 25% to 50%

loss.

Grade III:

Grade III sockets are the most deficient

and include any socket with inadequate apical

topography, insufficient interproximal bone, or more

than 50% loss of buccal plate.

PROCEDURES TO BE OBSERVED TO

PRESERVE THE ALVEOLAR SOCKET:

TOOTH EXTRACTION:

Atraumatic extraction techniques should be

used to minimize damage to the alveolar bone during

tooth extraction. The Easy-X-tractor (Fig 4) is a

device designed to extract single-rooted teeth with

minimal trauma and does not require flap elevation.

If the tooth structure is too broken down, the

roots can be carefully sectioned into fragments and

extracted without placing pressure on the alveolus.

Once the tooth is extracted, the alveolus should be

thoroughly debrided, removing all of the granulation

tissue.

Fig

4: Easy-X-tractor used for extraction

FLAP DESIGN:

The extraction of a tooth results in a decrease

in height of the papillae. The loss of papillae height

is increased with the elevation of buccal and lingual

flaps.

In areas of esthetic concern, consideration

should be given to extracting the tooth and

augmenting the socket without elevating a flap or the

use of a mini-flap on the buccal side preserving the

papillae (Fig 5).

Fig 5:

Flap elevation

POST-OPERATIVE MANAGEMENT:

The most important step in the post-operative

management of augmented extraction sockets is the

placement and shaping of the temporary tooth that is

placed over the extraction area. The loss of papillae

height from extraction can be largely restored with

the use of removable or fixed provisional appliances.

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Dhwani et al: An overview of Socket Preservation

HEALING PATTERN OF SOCKET

ALVEOLUS:

Residual ridge remodelling, begins with a

cascade of inflammatory reactions that is activated

immediately after tooth extraction.

Healing of extraction sockets can be explained

in five different stages (Fig 6).

Fig

6: Healing pattern of socket alveolus

GRANULATION STAGE:

The granulation stage lasts around five days.

The early granulation tissue first appears at the

bottom of the socket and spreads laterally, up the

socket walls.

ANGIOGENIC STAGE:

The second phase, the initial angiogenic

stage, happens within the first week of granulation

stage. New trabeculae have begun to appear at the

bottom of the socket, and the blood clot in the center

has begun to shrink.

NEW BONE FORMATION STAGE:

The third phase begins two weeks after the

tooth extraction. Sinusoid formations that began in

the earlier phases yield bone trabeculae. At this point

osteoid, can be detected. The bone formation follows

the pattern of the sinusoid formations, which have

mostly formed vertically starting in the apical region.

BONE GROWTH STAGE:

The bone growth stage which is characterized

by well developed, thickened trabeculae that now

fill 2/3rds of the socket. This happens 4-5 weeks

after extraction. This woven bone is referred to as

spongiosa. Some sinusoids are still forming in the

coronal portion of the socket, while the apical portion

appears to be more mature with less sinusoids.

BONE REORGANIZATION STAGE:

The final stage is the bone reorganization

stage which is usually evident around six weeks after

extraction. The primary spongiosa now develops into

secondary spongiosa, or more lamellar bone, and is

present in higher percentages towards the apical end

of the residual socket.

TECHNIQUES FOR SOCKET

PRESERVATION:

The techniques available today are based on

the principles of guided bone regeneration, which

have been used in periodontal regeneration since

1982.

The technique consists of isolating a bony

space, in this case an extraction socket with a barrier

membrane, to exclude the epithelial cells and thereby

have the space filled with bone. The use of a bone

replacement graft alone results in some preservation

of alveolar height and width but less than with a

barrier membrane.

MATERIALS USED FOR SOCKET

PRESERVATION:

Guided Bone Regeneration (GBR) techniques

utilize barrier membranes to refrain gingival cells

from penetrating into the defect to be regenerated

(Fig 7). There are numerous barrier membranes

available today for guided bone regeneration.

Fig 7: Socket preservation using bone grafts and

GTR membrane

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Dhwani et al: An overview of Socket Preservation

GTR MEMBRANES:

They can be either resorbable or non-

resorbable membranes.

NON RESORBABLE MEMBRANES:

Non-resorbable membranes were the first

devices approved for clinical use. Non-resorbable

membranes require a second surgical procedure

for removal. The need for additional surgery is

accompanied by concerns over patient acceptance,

time, cost, and possible morbidity associated with

any surgical procedure.

Nyman and colleagues initially used a

membrane constructed from Millipore® (cellulose

acetate) filters.

Polytetrafluoroethylene is a fluorocarbon

polymer with exceptional inertness and

biocompatibility.

Teflon®, an expanded polytetrafluoro-

ethylene (e-PTFE) membrane consists of 2 parts:

a collar portion, having open pores to allow in-

growth of connective tissue and to prevent epithelial

migration; and an occlusive portion, preventing the

flap tissues from coming into contact with the root

surface.

The Gore-Tex expanded polytetrafluoroethylene

periodontal device features two structural designs to

address specific needs. An open microstructure collar,

corresponding to the coronal aspect of the device, to

promote connective tissue in-growth and to support

wound stability and inhibit epithelial migration.

The remainder of the device is a partially occlusive,

structurally relatively stable membrane serving to

provide a space for regeneration as well as a barrier

towards gingival flap tissue invasion or collapse onto

the root surface.

The Gore-Tex expanded polytetrafluoroethylene

membrane has been modified by incorporation of

titanium reinforcements. The titanium reinforcement

is set between two layers of expanded polytetra-

fluoroethylene, resulting in a device with identical

surface properties and improved mechanical strength.

Use of a resin-ionomer barrier has excellent

space-making properties; however, it could be

difficult to fabricate in-situ.

A rubber dam offers little rigidity to assure

space maintenance, can be tedious to manipulate,

and exhibits no tissue integration.

A composite non-absorbable device made out

of knitted nylon fabric mechanically bonded onto a

semipermeable silicone membrane and coated with

collagen peptides (Bio Brane) has also been used.

RESORBABLE MEMBRANES:

Resorbable membranes do not require

additional surgery for removal, which reduces patient

discomfort, chair-side time and related cost, while

eliminating potential surgery-related morbidity.

A. Natural products:

Collagen is the principal component of

connective tissue and provides structural support for

tissues throughout the body. It possesses the ability

to stimulate platelet attachment and to enhance fibrin

linkage, which may assist initial clot formation and

stabilization, leading to enhanced regeneration.

A type I collagen guided tissue regeneration

membrane derived from bovine deep flexor (Achilles)

tendon is widely used.

Another type I collagen membrane

derived from calf pericardium and cross-linked by

diphenylphosphorylazide has been evaluated for

guided tissue regeneration. Other natural products

tested as guided tissue regeneration devices include

duramater, cargile membrane, oxidized cellulose and

laminar bone.

B. Synthetic products:

Synthetic absorbable devices most

commonly used are poly-a-hydroxy acids, which

include polylactic acid, polyglyco1ic acid, and their

copolymer, polyglycolide-lactide.

A double-layered absorbable device

(GUIDOR) made of polylactic acid and a citric acid

ester was the first to gain FDA approval.

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Dhwani et al: An overview of Socket Preservation

Another synthetic absorbable device

(RESOLUT) is a composite consisting of an occlusive

membrane of glycolide and lactide copolymer and a

porous web structure of bonded polyglycolide fiber.

Fiber of polyglactin 910, a copolymer of glycolide

and L-lactide (90/10 molar ratio), is used to prepare

a tightly woven mesh (VICRYL Periodontal Mesh).

The ATRISORB barrier is the only approved guided

tissue regeneration device to be manufactured

chairside.

Acellular dermal matrix (ADM) is derived from

human donor skin tissue.

It is commercially

available from tissue banks sanctioned by the

American Association of Tissue Banks (AATB).

GUIDED BONE REGENERATION:

The PASS principle:

P- Primary wound closure

A- Angiogenesis

S- Space maintenance

S- Stabilization

remains a cornerstone for successful guided bone

regeneration.

TYPES OF BONE GRAFTS:

The 4 types of grafts being used are autografts,

allografts, xenografts and alloplasts.

AUTOGRAFTS:

Autografts are taken from one part of a

patient’s body and transferred to another. The basis

for current periodontal bone grafting procedures can

be traced to Nabers and O’Leary in 1965.

Osseous coagulum is obtained by using rotary

instruments on intra-oral bone in the surgical site and

then mixing the particles of bone with the patient’s

blood.

Bone blend is cortical or cancellous intra-

oral bone that is obtained with a trephine, chisel

or rongeur. It is placed in an amalgam capsule and

triturated into particle size in the range of 100 to 200

µm.

Autografts can be either extra-oral or intra-

oral in origin.

A) EXTRA – ORAL AUTOGRAFT:

Autografts of iliac cancellous bone and

marrow offer the greatest potential for induction of

new bone in the periodontium.

Iliac bone marrow autografts (Fig 8) have

proven to be the most predictable graft materials for

bone growth. However, they are no longer popular.

Complications associated with the use of fresh iliac

bone marrow include root resorption and ankylosis,

in regards to bone grafting around teeth.

Fig 8: Iliac bone marrow autograft

B) INTRA ORAL AUTOGRAFTS:

Intra oral autografts have been harvested

from various intra-oral sites including edentulous

ridges, the maxillary tuberosity, post- extraction

healing sites and tori or exostoses.

ALLOGRAFTS:

They consist of tissue transferred from one

individual to another genetically dissimilar individual

of the same species.

These grafts can be categorized as

demineralized frozen or freeze-dried bone allograft

(dFDBA) or mineralized frozen or freeze-dried bone

allograft (FDBA). FDBA provides an osteoconductive

scaffold and elicits slower resorption than dFDBA

when implanted in mesenchymal tissues.

XENOGRAFTS :

They are tissue grafts transferred from one

species to a different species. It has been observed

in some short-term studies that while the placement

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Dhwani et al: An overview of Socket Preservation

of biomaterial in alveolar sockets may promote bone

formation and ridge preservation, the graft may also

delay healing.

ALLOPLASTS:

Alloplastic bone substitutes like calcium

sulfate, bioactive glass and polymers are used.

The Bio-Col technique involves the placement

of Deproteinized Bovine Bone Matrix (DBBM)

particles in the extraction socket and then covered

with a collagen plug or membrane sutured into place.

RECENT TRENDS:

• Novel tissue engineering therapies have been

developed including the delivery of growth factors

incorporated in carriers, the stimulation of the

selective production of growth factors using gene

therapy, and the delivery of expanded cellular

constructs.

• The use of rhBMP-2 absorbed in a collagen

sponge for alveolar ridge preservation after tooth

extraction was published in 1997.

• PDGF-BB in a β-TCP carrier is a material accepted

from the FDA for regeneration of bone and PDL in

guided tissue regeneration procedures.

• One of the naturally obtained membrane for socket

preservation is platelet-rich fibrin (PRF). Platelet-

rich fibrin (PRF) is the second generation of

platelet concentrates.

• More recently, tissue repair cells (TRC), a cell

construct derived from each patient’s bone marrow

and cultivated using automated bioreactors to

concentrations not achievable through a simple

bone marrow aspiration, were evaluated in socket

healing.

CONCLUSION:

“ The future lies in preserving the past.”

- Peter Westbrook

Bone resorption after tooth extraction

averages about 3-5 mm in a period of 6 months.

Socket preservation procedures are effective in

limiting horizontal and vertical ridge alteration

following tooth extraction. The use of barrier

membranes alone might improve normal wound

healing in extraction sites. The reduction in bone

resorption averages upto 2-4 mm in width of the

alveolar bone with the help of socket preservation.

Hence this technique along with the help of GTR

and GBR is very effective in preserving the alveolar

socket.

FINANCIAL SUPPORT AND

SPONSORSHIP:

Nil

CONFLICTS OF INTEREST:

There are no conflicts of interest.

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