INTRODUCTION infection. The microleakage between the root canal and

INTRODUCTION

Root canal
obturation is a procedure in which the root canal space is filled with
canal-filling materials at the final stage of root canal treatment, after
cleaning and shaping. The objective of root canal obturation is to prevent or
treat periapical disease by preventing recontamination by bacteria that may
have remained in the dentinal tubules or that exist in the oral cavity (Kim, et
al, 2017).

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A three
dimensional seal of the root canal system is achieved by proper root canal
obturation to prevent the recurrence of bacterial infection. The microleakage
between the root canal and the periapical tissues is hindered leading to death
of any surviving microorganisms. This prevents the entry of nutrients and toxic
bacterial products into the periapical tissues. Various techniques have been
developed to achieve the proper obturation of root canal system including the
vertical compaction, lateral compaction and carrier based obturation (Gupta, et
al, 2015).

Rotary
nickel-titanium (NiTi) instruments are widely used for root canal
instrumentation. This widespread use of these instruments has caused
manufacturers to offer corresponding gutta-percha cones that match the taper
and diameter of the instruments. It is claimed that these cones will match the
taper and diameter of the canals prepared with the rotary NiTi instruments.

Obturation with these cones used as a single-cone technique is alleged to
provide a 3D obturation in less time than traditional obturation techniques and
to ensure a high volume of gutta-percha in the canal (Schafer, et al, 2013).

The root canal
preparations with NiTi rotary systems are more conical than manual
preparations. Tapered single cones were introduced in the market in order to
improve the gutta-percha/root canal sealer balance. If the diameter and
conicity correspond exactly with the final shaping instrument, the quality of
obturation would be superior to that of the classic single-cone technique
(Robberecht, et al, 2012).

The advent of
computed tomography (CT) has started a revolution of information in health
studies and has contributed to planning, diagnosis, treatment, and prognosis
analysis of several diseases. Cone-beam computed tomography (CBCT) is a
recently developed technology with potential for applications in different
areas of research and clinical dentistry. It designed for imaging hard tissues
of the maxillofacial region, and capable of providing a 3-dimensional
representation of the maxillofacial skeleton with minimal distortion (Decurcio,
et al, 2012. Scarfe, et al, 2006).

BACKGROUND

            Complete obturation of the root
canal with an inert filling material and creation of a hermetic apical seal are
the goals of successful endodontic treatment. Furthermore, the integrity of the root
canal filling in the apical few millimeters is one of the criteria believed to
be important for achieving successful endodontic treatment. Most
obturation methods make use of a solid core cemented in the root canal with a
sealer (Gencoglu, et al,
2002).?

In many
studies the percentage of gutta-percha filled area (PGP) has been measured. In general,
the higher the PGP, the smaller the area of sealer and voids, the better the
quality of the root canal filling. The PGP score may reveal filling problems in the
oval canal. When the wings are occupied by debris, the PGP score will be lower
than in round canals. Because the shape of the wings is irregular, it may be
difficult to place secondary cones into the wings when the root canal is filled
using the cold lateral compaction technique, so here too the PGP score may be
lower than in the round canals (Sluis, et al, 2005).

The Thermafil
obturation technique resulted in virtually no gaps and very low amounts of
sealer on the root surface, unlike the lateral condensation technique. Tubule
sealer penetration occurred with both techniques, but was deeper, especially in
the mid and apical zones, with the lateral condensation technique (Guigand, et
al, 2005).

The quality of
root fillings of the thermoplasticized gutta-percha in comparison to cold
lateral condensation has been evaluated in several studies, with differing
conclusions. On radiographs, the Thermafil obturation technique generally
showed better adaptation than lateral condensation, but in the apical third the
results for both methods were similar. Scanning electron microscopic
observations for Ultrafil, Thermafil and lateral condensation showed better
dentinal wall adaptation in roots obturated with thermoplasticized gutta-percha
than in laterally condensed root canal fillings, regardless of the presence or
absence of a smear layer (Kqiku,
et al, 2006).

            The final objective of endodontic
procedures should be the total obturation of the root canal space. Many root
canal filling techniques have been developed in the hope of achieving total
root canal obturation. Most of the currently employed techniques use either a
solid core and a cementing substance, or a plastic material which can be
adapted more or less to the shape of the root canal system (Schilder,2006).

Gutta-percha
exhibited the lowest percentage of voids and gaps in the root sections except
at the apical third where GuttaFlow showed the lowest gaps and voids. This also
can be attributed to the filling technique, because the manufacturers of
GuttaFlow recommend that it is dispensed first in the apical part of the root
canal, and then a master gutta-percha cone is placed. This ensures the least
amount of voids and gaps in the apical third (Hammad, et al, 2009).

Numerous
materials and techniques have been developed for filling root canals. It has
been reported that the quality of adaptation between the surface of the root
canal and the gutta-percha is uncertain in fillings created by the lateral
condensation technique, even though this method has the advantage of creating a
tight apical seal through compression of several gutta-percha cones with
spreaders. However, canal curvature and other anatomic features may prevent
achievement of this tight seal.6 In addition, metal spreaders must be placed in
the canal several times during the filling process for lateral compaction of
the gutta-percha, but practitioners may have difficulty achieving the required
balance between optimal compression of the gutta-percha and avoidance of root
fracture through application of too much pressure (Tasdemir, et al,2009).

On a study of
using micro-CT-based quantitative three-dimensional method for analysis of root
canal filling adaptation to the canal walls was presented. It may serve as a
useful tool to study and compare the quality of root canal fillings. Within the
limitations of the present study, the self-adjusting files allowed better
cleaning and shaping and better adaptation of the root canal filling than those
allowed by rotary files (Metzger, et al, 2010).

Shaping
facilitates three-dimensional cleaning by removing restrictive dentin, allowing
a more effective volume of irrigant to penetrate, circulate, and potentially
clean into all aspects of the root canal system. Well-shaped canals result in a
tapered preparation that serves to control and limit the movement of warm gutta
percha during obturation procedures. Importantly, shaping also facilitates 3D
obturation by allowing pre-fit pluggers to work deep and unrestricted by
dentinal walls and move thermosoftened obturation materials into all aspects of
the root canal system. Improvement in obturation potential is largely
attributable to the extraordinary technological advancements in shaping canals
and cleaning and filling root canal systems (Ruddle, 2010).

A correlation
was found between root canal morphology and the master cone adjustment
variables in the “Single-cone” group. When the morphology was oval, we observed
better gutta-percha adjustment. This could be explained by the smaller amount
of friction between the master-cone and the root canal walls in an oval canal
compared with a circular canal. This correlation was not found in the “Combined
system” group. This was to be expected, because if the gutta-percha is heated
and condensed, the root canal morphology no longer matters (Robberecht, et al,
2012).

To cope with
such different obturation difficulties many root obturating techniques have
been evaluated over the years and the filling materials from simple paste
mixtures to silver points with sealing cements. To obturate root canal system the
ideal obturating material chosen should be non-irritating, non-toxic,
radiopaque, easily manipulated, insoluble in tissue fluids and able to adapt to
canal walls. Gutta-percha
is currently the material of choice due to its inertness, biocompatibility,
dimensional stability and plasticity (Qureshi, et al, 2012).

Three-dimensional
obturation of the prepared root canals is essential to long- term clinical
success of root canal therapy. The root canal system should be sealed apically,
coronally, and laterally and the obturation material should be of uniform
density. Epley et al and Schilder suggested that the ideal root canal obturating
material should be well-adapted to the canal walls and its irregularities and
the entire length of the canal be densely compacted with homogenous mass of
gutta-percha. Several materials and techniques have been developed for
achieving a successful obturation, gutta-percha is the most commonly used root
canal obturation material and its physical properties have made it possible to
use it in several different techniques (Mustafa, 2013).

Lateral
consideration of gutta-percha has been proven to be a very popular and
clinically effective filling technique. However, Schilder reported that final
filling by lateral consideration resulted in a non-homogeneous mass of many
separate gutta-percha cones pressed together and joined only by friction and
the cementing substance. Warm gutta-percha best fulfills the requirements of a
root canal filling because homogeneity is provided throughout the entire length
of filling (Samson, et al,
2013).

To achieve
long-term stability, the filling should be well adapted to the canal walls, and
its irregularities and the entire length of the canal should be densely
compacted with a homogeneous mass of gutta-percha (Wolf, et al, 2014).

The maximum
amount of obturating material was observed in Calamus group followed by
Thermafil and lateral compaction. Minimum voids were seen in obturation by
Calamus technique (Gupta, et al, 2015).

In a study
that concluded the carrier-based gutta-percha obturation systems revealed significantly
higher percentage of gutta-percha-filled area in comparison to single-cone and
lateral condensation techniques (Yilmaz, et al, 2016).

In all the
pervious study showing that different obturation method can get different
result which will affect in the quality of the root canal filling. Using
guttaflow and carrier-based gutta-percha obturation systems show the least
amount of voids and also the highest in filled area in comparing to the others
technique. 

RESEARCH DESIGN AND METHODS

Subject: This is an experimental study which will be
conducted at the UQUDENT hospital of umm al-qura university Makkah, KSA. The
total number of extracted teeth will be 30.

Ethical approval: Ethical approval from
institutional reviewing board will be obtained before starting this study.

The Inclusion criteria for the study samples
is as follows:

§  Extracted teeth with single
canal and closed apex.

The exclusion criteria for the study samples
is as follows:

§ 
Tooth with multi-canal.

§ 
Tooth with crack or fractures.

§ 
Tooth with open apex.

§ 
Tooth with sever curvature.

Thirty extracted human teeth were collected
and cleaned from any debris then stored first with 10% of sodium hypochlorite for
one day and then stored in saline. Teeth then decoronated with a diamond wheel
and achieve working length about 16 mm using K-type file number 10 inserted
into the canal until it visible from the apical foramen, working length was set
1mm short of the length. Teeth divided randomly into three group (n=10) and
mounted in transparent acrylic resin. For the cleaning and shaping start with
K-type file number 15 to establish apical patency and followed with K-type file
number 20 and 25, irrigation with 2 ml of 2.5% sodium hypochlorite between each
file. The root canal then instrumented using ProTaper Next rotary system
according to the manufacturers’ instructions, three file used X1-yellow, X2-red
and X3-blue. Irrigation with 2 ml of 2.5% sodium hypochlorite between each file
during instrumentation followed by 17% of EDTA aqueous solution. EDTA 17% used
for final rinse. Dryness with paper point. According to the groups we have
three obturation techniques.

 The
first group will receive a root canal filling by using System-B with
gutta-percha cartridges, master gutta-percha cone inserted to the canal and
coated with resin based to the full working length, pack the filling material and
place within 5 mm to the canal terminus, then flow the gutta-percha material
into the canal and compact the canal with plugger until the desire level.

The second group will receive a root canal
filling by lateral condensation technique, master gutta-percha cone coated with
resin based sealer and inserted to the full working length, accessory
gutta-percha cone coated with the same sealer and inserted to the canal and
lateral condensation performed until the canal filled and can’t introduce more
accessory gutta-percha cone.

The third group will receive a root canal
filling by using single cone technique, F3 ProTaper gutta-percha cone selected
and coated with resin based sealer and inserted to the full working length.

All the three group will place at the
computed tomography machine; three horizontal section will be analysed (apical
third, middle third and coronal third).

 Validity and Reliability of the
test: The intra examiner consistency will be
maintained through training and repeat examination until satisfaction result
obtain. replication of statistically significant results, under the same conditions and
generate the same results.

Statistical
analysis: Data
will be collected and tabulated and statistically evaluated by Statistical
Package for Social Science (SPSS) Version 22 for mac.