JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

JIDAM

“An Official Journal of IDA - Madras

Available online

SYSTEMATIC REVIEW

“RELATIONSHIP BETWEEN IMPACTED MANDIBULAR THIRD MOLAR AND

MANDIBULAR CANAL” DOES CONE BEAM COMPUTED TOMOGRAPHY

IMAGING PROMISE MORE EFFECTIVE DIAGNOSIS BEFORE EXTRACTION THAN

ORTHOPANTAMOGRAPH? - A SYSTEMATIC REVIEW

Dr .Sanjana.S, Dr. DivyaLalitha.N, Dr. Prabu. D, Dr. Sunayana Manipal, Dr. Rajmohan, Dr. Bharathwaj.V.V

Department of Public Health Dentistry,

SRM Dental College, Ramapuram, Chennai, Tamilnadu, India.

ABSTRACT

BACKGROUND:

Proper diagnosis of impacted mandibular third

molars (IMTM) is essential to prevent injury at the site during extraction

and aftermath surgical complications. OPG (Orthopantomograph) is

the most common diagnoﬆic aid followed nowadays. However, since

the two dimensional imaging does not provide adequate details for

diagnosis, CBCT (Cone-Beam Computed Tomography) is preferred

in order to avoid such impediments as it provides higher quality

imaging and makes the extraction procedure much easier with its

ample detailing for diagnosis.

AIM:

To compare preoperative radiography with cone-beam

computed tomography in the assessment of the relationship between

impacted mandibular third molar and mandibular canal.

Address for Correspondence:

Dr. DivyaLalitha. N., MDS,

Department of Public Health Dentistry,

SRM Dental College, Ramapuram,

Chennai-600089, Tamilnadu, India

Email id:

diyan2409@gmail.com

Received

: 26.08.2020

Accepted

: 15.09.2020

Published

: 27.09.2020

METHOD:

A systematic review of the records comparing panaromic

radiography with cone-beam computed tomography for the pre-

operative assessment of impacted mandibular third molar and its

relationship with the mandibular canal was done. A literature review

was performed using Medline, Pubmed, Science direct, and Cochrane.

Total of 383 articles appeared from various sources; all articles were

screened and 15 were related to the research question. This review was

reported according to the PRISMA guidelines.

RESULTS:

With the 15 articles included in the systematic review as

qualitative synthesis, the presence of darkening of roots and interruption

of the white line in OPG, as both separate findings and in association

with each other are effective in influencing the risk relationship

between IMTM and mandibular canal, which further certainly

require a 3D evaluation (CBCT) before performing the surgery.

CONCLUSON:

CBCT imaging provides much a promising

evaluation in determining the relationship between impacted

mandibular third molars and mandibular canal which is more useful

than OPG imaging before the extraction to elude complications both

during and after the procedure.

KEYWORDS:

CBCT, OPG, Extraction, Systematic Review

To access & cite this article

Website: jidam.idamadras.com

DOI:1.37841/jidam_2020_V7_I3_01

Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

INTRODUCTION:

Wisdom teeth (often called as 8’s) are the third

and the final set of molars to erupt in the oral cavity

during the late teens or early twenties. Historically,

they are called so because they come at a more

mature age that people are said to become wiser and

hence nicknamed “wisdom teeth”. Anthropologists

accept the fact that our ancestors had larger jaw size

that helped them occupy many molars up to the 5

molars, which helped them grind on rough food like

roots, leaf, nuts and meat that required more chewing

power. With time, generation, and development of

modern diet of softer foods along with prodigies

of a modern technologies such as forks, spoons and

knives, wisdom teeth slowly became nonexistent.

Due to this, evolutionary biologists have classiﬁed

wisdom teeth as ‘vestigial organs’, or body parts that

have become functionless with evolution. Human

jaws have become smaller throughout evolutionary

history, so when wisdom teeth form, they often

become impacted, or blocked by other teeth around

them which do not let them erupt in the oral cavity.

Also, if wisdom teeth partially erupt, food tends to

get trapped in the gum that surrounds it, which in the

process causes bacterial growth and simultaneously

infection. They also can lead to problems such as

crowding and displacement of other permanent teeth.

Generally, these third molars erupt in the oral cavity

at the age of 17-24 years

Very rarely, cyst (fluid-filled sac) formation

in the soft tissue surrounding the impacted wisdom

teeth can also occur, leading to bone destruction,

jaw expansion ultimately damaging the surrounding

teeth. Even more uncommonly, tumors can develop

from the cysts causing pathological fracture of the

jaws if the tumor or cysts exceeds growth.

Wisdom teeth can be removed at any age if

once it has been identified to start creating problems.

However, it is best to have it extracted between the

age of 18 and 24. Another main factor influencing

its removal from the oral cavity is when the root has

developed to about two-thirds of its full size (which

maybe sooner or later than 18), depending from

individual to individual. After the age of 24, the roots

of wisdom teeth are fully formed leading to complex

extraction procedures.

The removal of wisdom teeth at older ages may

require even more complicated surgeries where the

healing time could be slower with high risks of

complication.

Impacted third molars occur in both

maxillary and mandibular jaws. Adequate diagnosis

is essential before the extraction procedure to

prevent any complication. Panoramic radiography

or Orthopantomograph (OPG) is the most common

diagnostic aid for third molar surgeries. It is

commonly used to evaluate the type of impaction,

angulation, and morphology of roots. Nevertheless,

the spatial relationship between the mandibular

canal and impacted mandibular third molars (IMTM)

cannot be assessed using panoramic radiographies

Since it provides only a two-dimensional view, the

vicinity of the tooth is not as accurate as ‘Cone-beam

Computed Tomography (CBCT)’, which provides

higher quality imaging in three-dimensional views.

It has higher special resolution, and radiation from

CBCT is also minimal when compared to medical

computed tomography

IMTM are the most commonly impacted

teeth in the oral cavity. According to a study, third

molar impactions are occurring in about 73% of the

young adults in Europe

. Its surgical removal could

lead to several postoperative complications if it is

not removed atraumatically. Because of its location

(closer to the mandibular canal / inferior alveolar

canal (IAC), it has been proven that impacted third

molars are the main reason for permanent paralysis

of the inferior alveolar nerve. The nerve injury

ranges from 0.6 to 5.3% with permanent injury <1%

of patients

Although OPG oﬀers wider-ranging coverage

and easy access, detecting the meticulous proximity

of the IMTM to the IAC in patients is not possible.

Therefore, it is essential to extend the analysis by

preferring CBCT. This systematic review aims at

highlighting the benefits of CBCT by comparing its

accuracy with OPG in patients who have their IMTM

in close approximation with mandibular canal before

surgery. The criteria such as ‘presence’ or ‘absence’ of

corticalization around the IMTM in both diagnostic

imaging techniques are compared and evaluated.

Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

MATERIALS AND METHODS

STUDY DESIGN:

Systematic review of the records

comparing Panoramic Imaging (OPG) and Cone

Beam Computed Tomography (CBCT) for pre-

operative assessment of impacted mandibular third

molars with mandibular canals.

OBJECTIVE:

To compare panoramic radiography with

cone-beam computed tomography in the assessment

of the relationship between impacted mandibular

third molars and mandibular canals.

SEARCH ENGINES:

• PUBMED

• ELSEIVER SCIENCE DIRECT

• COCHRANE LIBRARY

• WILEY ONLINE LIBRARY

• Other additional sources

SEARCH STRATEGY:

All the published articles which compared

the diagnostic value of Cone Beam Computed

Tomography with Panoramic Radiography in the

assessment of relationship between Impacted

Mandibular Third Molar and Mandibular Canal pre-

operatively. Articles from databases such as PubMed,

Elsevier Science Direct, Cochrane library, Wiley

online library and additional sources were included

in the review. The articles were searched to collect

the relevant data using MeSH terms, “Cone-Beam

Computed Tomography, Panoramic Radiography,

Impacted Mandibular Third Molar and Mandibular

Canal”. According to the PRISMA guidelines, the

MeSH terms were altered in each search engine,

where the results produced were many or too few.

INCLUSION CRITERIA:

• Studies comparing pre-operative evaluation of

IMTM with mandibular canals with OPG and

CBCT.

• Studies with only clinical trials.

• Studies showing corticalization between

mandibular third molar and mandibular canal.

EXCLUSION CRITERIA:

• Review articles.

• Articles proving only CBCT & only OPG as

parameters.

• Other parameters apart from CBCT and OPG.

• Other structures apart from mandibular canal with

impacted mandibular third molar.

• Other teeth apart from mandibular third molars.

• Pilot studies and RCT.

• Other lesions and their surgeries.

• Post-Operative studies comparing OPG with

CBCT.

• Apart from corticalization, other criteria were

analyzed.

• Animal studies.

RESULTS:

A total of 383 publications based on the

topic were identiﬁed. Of these, 23 were detected as

duplicated and extracted. After extraction of the

duplicates, the remaining articles were screened

thoroughly and 20 full text articles were independently

assessed. With the application of exclusion criteria,

15 studies were included in the systematic review as

qualitative synthesis. Fig 1 shows the flow diagram

of the above work down.

JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

TABLE 1: CHARACTERISTICS OF INTERVENTIONS IN THE INCLUDED STUDY

AUTHOR

YEAR SAMPLE

SIZE

PATIENT

CHARACTERISTICS

NUMBERS (CASE/

CONTROL)

Daniela Guimardes

de Melo Albert et al

2006

19 individuals

(24 teeth, 14 right

side and 10 left

side)

9 males and 11
females with impacted
mandibular third
molars.

24 teeth were
assessed with OPG and
compared with CBCT

Weeraya
Tantanapornkul et al

2007 135 individuals

(142 teeth)

50 males and 85
females with impacted
mandibular third
molars.

142 teeth were
assessed with OPG and
compared with CBCT

Kenji Nakamori et al

2008 443 individuals

(695 teeth)

247 males and 196

females with impacted

mandibular third

molars.

576 OPG and 119
were compared with
CBCT

H.Ghaeminia et al

2009 42 individuals

(56 teeth)

20 males and 22

females with impacted

mandibular third molars.

56 teeth were

assessed with OPG and

compared with CBCT

Shravan Kumar

Katakam et al

2012 30 individuals

(42 teeth)

11 males and 19

females with impacted

mandibular third molars.

42 teeth were

assessed with OPG and

compared with CBCT

F S Neves et al

2012 72 individuals

(142 teeth)

28 males and 44

females with impacted

mandibular third molars.

142 teeth were

assessed with OPG and

compared with CBCT

Shoaleh Shahidi et

2013 96 individuals

(132 teeth)

46 males and 50

females with impacted

mandibular third molars.

132 teeth were

assessed with OPG and

compared with CBCT

JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

Ilkay Peker et al

2014

191
individuals

(298 teeth)

68 males and 123

females with impacted

mandibular third

molars.

298 teeth were

assessed with OPG and

compared with CBCT

Saraydar-Baser R et al

2015

60
individuals

( right side

41, left

side 19)

28 males and 32
females with impacted

mandibular third

molars.

60 individuals ( right

side 41, left side 19) were

assessed with OPG and

compared with CBCT

Larissa Rangel
Peixotoet al

2015

50
individuals

(73 teeth)

26 males and 24

females with impacted

mandibular third

molars.

73 teeth were

assessed with OPG and

compared with CBCT

MahmudaAkter et al

2016

60
individuals

60 individuals with
impacted mandibular

third molars.

60 individuals were

assessed with OPG and

compared with CBCT

SonaliGhai et al

2017

60
individuals

(53 teeth)

60 individuals with
impacted mandibular

third molars.

53 teeth were

assessed with OPG and

compared with CBCT

Kate L. Winstanley et
al

2017

55
individuals

(100 teeth)

15 males and 40

females with impacted

mandibular third

molars.

10 teeth were

assessed with OPG and

compared with CBCT

Darshana S Nayak et
al

2018

24
individuals

(40 teeth)

5 males and 19

females with impacted

mandibular third

molars.

40 teeth were

assessed with OPG and

compared with CBCT

Vinay Kumar Reddy

Kundoor et al

2018

individuals

(60 teeth)

16 males and 24 females

with impacted

mandibular third molars.

60 teeth were assessed with

OPG and compared with

CBCT

TABLE 1 shows the characteristics of intervention in the included ﬆudies. In all the 15 studies, the accuracy of

CBCT images were compared with OPG images in a controlled group which differed in sample size, gender and number of
impacted teeth diagnosed. Only the OPG which showed IMTM having close approximation with mandibular canal were
further preferred for taking up CBCT diagnosis.

JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

TABLE 2: OUTCOME DATA AS REPORTED IN INCLUDED STUDIES

AUTHOR

YEAR EFFECT MEASURE

RESULTS

P VALUES

Daniela

Guimardes

Melo Albert et al

2006

Darkening of the root,

narrowing and deviation of the

canal, narrowing and bifid

apexes from OPG were

compared with CBCT and

evaluated.

Darkening of roots

(92.1%) was majorly seen

in CBCT along with

narrowing of mandibular

canal (12.9%) and apex.

Not Mentioned

Weeraya

Tantanapornkul et

2007

Interruption of the mandibular

canal wall, darkening of the

root, diversion of the

mandibular canal, and

narrowing of the root in

Panoramic radiography was

evaluated using logistic

regression. The sensitivity and

specificity between OPG and

CBCT was also calculated.

The interruption of the

mandibular canal was

proved as diagnostic

criterion of OPG image to

predict the neurovascular

bundle during extraction.

Also the a) sensitivity of

CBCT was 93% and b)

specificity 77% which

was far superior to that of

OPG.

a)p<0.05

b)p<0.05

Kenji Nakamori

et al

2008

Darkening, deﬂection and

narrowing of the root,

narrowing and diversion of the

canal and interruption of the

white line from OPG were

compared with CBCT for

presence and absence of

cortication. Chi- squared and

Logistic regression was carried

out.

There was significance for

a) darkness of the root, b)

diversion of the canal and

c) narrowing of the canal.

a) p=0.049

b) p=0.019

c) p=0.003

H.Ghaeminia et al

2009

Patients with close relationship

between IMTM and

Mandibular canal in OPG were

asked to take CBCT.

Darkening of the root,

interruption of white line of

the

mandibular canal,

diversion and narrowing of the

canal were evaluated with Chi-

Squared (X²) test. Less than

0.05 were considered

Only darkening of the root

showed significant

association with Inferior

Alveolar Nerve exposure

and Odds ratio (0.204).

p=0.007

JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

statistically significant.

Logistic regression was then

carried out.

Shravan Kumar

Katakam et al

2012

Darkening and deflection of

roots, narrowing of apex and

the canal, deviation of canal,

deﬂection of white line and

bifid apexes from OPG were

evaluated and compared with

CBCT. Chi-squared and Z test

was performed.

Z-value >1.5 in darkening

of roots (1.98), deﬂection

of root (2.00), z-value = 0

in narrowing of canal and

dark, biﬁd apexes. Also it

showed significant p-

value in all the

radiographic signs except

narrowing of mandibular

canal, dark and bifid

apexes.

p<0.05

F S Neves et al

2012

Comparing the Panoramic

radiography and CBCT

findings according to the

relationship between the roots

of the third molars and the

mandibular canal

using

Fisher’s exact test, with a

significance level of p<0.05.

a)Darkening of roots and

b) interruption in white

line, as both isolated

findings and c)in

association with each

other revealed a

statistically significant

association with the

absence of corticalization

between the mandibular

third molar and the

mandibular canal in

CBCT images

a)p=0.0001

b) p=0.0006

c)p=0.002

Shoaleh Shahidi

et al

2013

The presence or absence of

direct contact on the

Panoramic radiographs was

evaluated by the following

four features, to find out the

close contact between the

tooth root and the mandibular

canal: (a) interruption of the

mandibular canal wall, (b)

darkening of the root,(c)

diversion of the mandibular

canal, and(d) root dilacerations

using logistic regression

Interruption of the cortical

lines on a panoramic

image raised the risk of

root and canal contact on

CBCT images (odds

ratio=5.75) and showed

the highest sensitivity

among the four signs of

association. However

darkening of roots,

diversion of mandibular

canal and root

dilacerations also

increased the risk of

association between the

tooth and the canal in

CBCT.

Not Mentioned

Ilkay Peker et al 2014

Darkening of the roots,

There was a significant

p<0.05

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diversion of the mandibular

canal, narrowing of the

mandibular canal and

interruption of the white line

on Panoramic radiography

were compared with CBCT

and evaluated by chi-square

and Fisher’s exact tests, with a

significance level of p<0.05.

association between

darkening of the roots and

interruption of the white

line on Panoramic images

and the presence of

contact between the

IMTM and the Inferior

Alveolar Canal (IAC) on

CBCT images (p<0.05).

Saraydar-Baser R

et al

2015

Darkening and contraction of

the tooth root, suspension of

the white cortical line of the

IAC, deviation or bending of

the IAC, Dark and bifid root

apex, island-shaped apex,

bending of the root and

contraction of the IAC from

OPG were compared with

CBCT for surgical outcomes.

Chi-squared, Fisher’s tests

were done along with

sensitivity and specificity.

a) Deﬂection and curvature
of the root, a) dark biﬁd
root apex near the nerve,
and c) an island-shaped
apex in OPG showed a
significant agreement with
the results of surgical
findings respectively.
d)CBCT results with the
surgical results was
evaluated at a

Kappa of 0.813, which is
important at (p = 0.001).
The sensitivity of CBCT
was found to be 100% and
specificity 94% in this
study.

a)p = 0.022

b)p= 0.027

c)p= 0.007

d) p = 0.001

Larissa Rangel

Peixotoet al

2015

Darkening,

deﬂection,

superimposition and narrowing

of the root, diversion of the

canal, interruption of the

cortex and bifid apexes from

OPG were compared with

CBCT ﬁndings. True and

False positive responses were

calculated.

The “True Positive”

response for darkening of

the roots and interruption

of the cortex with the

canal was 9,

superimposition of the

root showed 5 whereas

diversion of the canal

showed 2 and narrowing

of the root a) The P value

significance between the

three modalities were also

found (original, inverted

a)p=0.981

JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

and edge enhanced).

Mahmuda Akter

et al

2016

Darkening of roots and

narrowing of mandibular canal

from OPG to evaluate which

type of impaction had close

relationship with mandibular

canal. This was later compared

with CBCT ﬁndings.

The results show that

darkening of roots showed

majority of them in buccal

position and concluding

that horizontally impacted

mandibular third molars

have intimate relation

with inferior alveolar

canal.

Not Mentioned

Sonali Ghai et al

2017

Darkening of the root,

deviation and narrowing of the

canal, narrowing and

deﬂection of the root,

interruption of the white line,

dark and bifid root apexes

from OPG were compared

with CBCT with the presence

and absence of corticalization.

Darkening of the root

(DR) being the most

common 22.64% while

Interruption of White

Lines (IWL)being the

second most common

18.86% panoramic

radiographic ﬁnding,

when compared with

CBCT, absence of

corticalization was most

commonly associated with

DR and IWL, seen in 70%

of cases.

p<0.05

Kate L.

Winstanley et al

2017

Interruption of the white line

of the canal, tooth touching

white line of the canal,

darkening, narrowing and

deﬂection of the roots,

narrowing and deflection of

the canal from OPG were

compared with CBCT. Chi-

squared and Fisher’s exact

tests were carried out with

significance set at P < .05.

a) Darkening of the roots

(N = 22) and b)

interruption of the white

line (N = 47) were found

to be significant.

a)p=0.041

b)p=0.024

Darshana S

Nayak et al

2018

Darkening of roots, deﬂection

of the apex, dark and bifid

apexes, deviation and

narrowing of the canal from

OPG was compared with

CBCT. The CBCT images

were also evaluated in axial,

sagittal, and coronal planes to

determine true relationship

between the tooth and the

Darkening of the apex

(n=13, 56.5%) and
narrowing of the canal
(n=4, 17.4%) were the
signs most frequently

associated with a true
relationship on CBCT. P
value significance was

a)p< 0.001
b)p=0.001

c)p< 0.001

JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

canal in which radiographic

signs represent a true

relationship.

Statistical

analysis was carried out using

Chi‑square test of significance

P value <0.05.

calculated in three
sections, namely, a) the
coronal section, b) sagittal
and c) axial section.

Vinay Kumar

Reddy Kundoor

et al

2018

The association of Panoramic

radiography and CBCT

findings were analyzed using

Chi square test and Fisher’s

exact test for darkening of the

root, interruption of the

mandibular canal, and contact

of canal to root.

a) Panoramic radiographic

signs were statistically

associated with the

buccolingual position of

the mandibular canal

relative to the impacted

mandibular third molar on

CBCT. Contact with the

canal was more frequently

observed when the

interruption of the

mandibular canal and

darkening was seen on the

panoramic radiographs.

a)p< 0.01

TABLE 2 shows the outcome data of accuracy and reliability of CBCT diagnosis prior to the IMTM removal to

prevent poﬆ-surgical complications. All the 15 studies discussed had the same criteria (corticalisation) assessed.

TABLE 3: TECHNICAL CBCT DATA AND FURTHER INFORMATION FROM THE INCLUDED STUDIES

AUTHOR

CBCT SYSTEM

SCAN
SETTING

IMAGE
RESOLUTION

OTHER
INFORMATION

Daniela Guimardes de
Melo Albert et al

CommCat 752

(Imaging Sciences

Corporation)

Information
not provided

12.7 x 30.5 size

Information not
provided

Weeraya
Tantanapornkul et al

3DX multi image
micro CT

80Kv, 2mA
and 17

seconds

240 voxels

height, 320

voxels diameter

and isotropic

cubic voxels

with sides

0.12mm

Information not
provided

Kenji Nakamori et al

Information not
provided

Information
not provided

Information not
provided

JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

H.Ghaeminia et al

Classic i-CAT
CBCT unit
(Imaging Sciences
International)

120 kVp, 3–8
mA and 20
seconds

Field of view
6cm and voxel
size 0.25mm

Information not
provided

Shravan Kumar

Siemens volume

120kVP,

0.75 mm slice

Images

Katakam et al

access multislice

90mA

thickness

reconstructed in

spiral CT

sharp kernel H60S

in dental window

F S Neves et al

Classic i-CAT
CBCT unit
(Imaging Sciences
International)

120kVp/8mA 0.25mm voxel

size and ﬁeld
view of 8cm

Information not
provided

Shoaleh Shahidi et al

Kodak 9000

90 kVp,
6mA, and 10
seconds

Information not
provided

Ilkay Peker et al

Promax 3D unit
(PlanmecaOy,
Helsinki, Finland)

84 kVp, 9–14
Ma,6 seconds

0.16 mm voxel
size and a ﬁeld
of view of 8 cm

Information not
provided

Saraydar-Baser R et al

PromaxPlanmeca

80Kvp,
12mA for17
seconds

Information not
provided

Larissa Rangel Peixoto

Siemens AG

110kVp and

high-resolution

Information not

et al

1.60-8.21mA gray-scale SMM provided

Series monitor

was used

Mahmuda Akter et al

Information not

provided

Information

not provided

Information not

provided

Information not

provided

Sonali Ghai et al

ORTHOPHOS XG
3D imaging system

60–90kVp,
9–12mA

100 lm Voxel
size and 50*55
mm

Information not
provided

Kate L. Winstanley et

i- CAT Next

120 kV, 5

Information not Information not

Generation

mA ,14.7 or provided

provided

imaging system

26.9 seconds

(Imaging Sciences

International)

Darshana S Nayak et

Planmeca

96Kvp and

Size thickness

Information not

13,17

Promax3D

current 10mA 1mm in axial,

provided

coronal and

sagittal view

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Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

Vinay Kumar Reddy
Kundoor et al

New Tom Cone
Beam 3D imaging

120 kVp,
8mA

0.2mm voxel
size and ﬁeld
view of 8 cm

Information not
provided

TABLE 3 shows the CBCT data and other information from included studies

DISCUSSION:

This systematic review is based on 15 clinical

studies to find the eﬀects and reliability of CBCT

over OPG. Many other studies that also compared

the same or proved the eﬀectiveness were not

included due to the reasons already mentioned in Fig

1 (exclusion criteria). The studies in which the

criteria of ‘Corticalisation’ was used to assess the

relationship between IMTM and the mandibular

canal was considered to be the main factor for

including them in this systematic review. However,

the results of these studies were almost similar

stating that CBCT is the most accurate method for

diagnosis than OPG before the removal of IMTM to

prevent IAC injury and post-operative

complications.

There is evidence which states that the

presence of darkening of roots and interruption of

the white line in OPG, as both separate ﬁndings and

in association with each other is effective in

inﬂuencing the risk relationship between IMTM and

mandibular canal, which further certainly requires a

3D evaluation (CBCT) before surgery

3,6,9,10,13,15,16

The darkening of the root describes an increased

radiolucent feature with the impingement of the

canal over the third molar area and the strongest

sign for IAN exposure and post-operative

paresthesia

. It is also proven that there could be

marked thinning or perforation of the cortical

plates

. However, diversion and narrowing of the

mandibular canal and root dilacerations also

increased the risk of association between the tooth and

the canal in CBCT

4,10,14

. There was also a noteworthy

diﬀerence in the number of roots of IMTM and the

position (buccolingual) of the canal detected on OPG

versus CBCT imaging, proving that OPG diagnosis

solitarily is not sufficient

11,18

. Darkening of the roots

along with the narrowing of apices was also one of

the common OPG findings which instigated the need

for CBCT confirmation

8,17

. The sensitivity and

specificity of CBCT was found to be far superior

compared to OPG in various studies

5,12

According to the authors, the 3D examination of

CBCT should be carried out when darkening of roots,

narrowing of the mandibular canal, and interruption

of white line is observed on OPG

9-18

. However, the

predictability in judging the nerve lesion during the

procedure and post-operative complication, with the

consideration of the socioeconomic status, and the

high cost, the use of OPG pre-operatively before third

molar surgery is clearly justiﬁed

. CBCT depicts

nearness of the IMTM to neighboring anatomical

structures precisely which helps in creating

good surgical plan and predicting post-operative

complications which is of extreme importance in the

period of medico-legal consumerism

. Nonetheless,

OPG acts as a valuable guide in depicting mandibular

third molars when used in stepwise logistic manner

LIMITATIONS:

Although the use of CBCT for the diagnosis

of IMTM prior to its surgical removal is 100%

accurate and eﬀective, the cost factor being its major

drawback would result in negligence in the use of it.

CONCLUSION:

With the above-discussed articles in which

the significance of CBCT was proven statistically

more essential that OPG method of diagnosis, we

could conclude that CBCT evaluation in determining

the relationship between impacted mandibular third

molar and mandibular canal is more useful than

OPG imaging before the extraction of the tooth as it

majorly avoids complications both during and after

the procedures.

FINANCIALSUPPORTANDSPONSORSHIP:

Nil

JIDAM/Chennai/Volume:7/Issue:3/Pages 71 - 84/July - Sep 2020

Sanjana et al : Does CBCT imaging promise more effective diagnosis before extraction than OPG? - A Systematic Review

CONFLICTS OF INTEREST:

There are no conflicts of interest.

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