Journal of Dental & Oro-facial Research Vol 12 Issue 1 Jan 2016 JDOR

MSRUAS 3

ORIGINAL RESEARCH

INFLUENCE OF APICECTOMY MODALITIES

ON APICAL SEAL OF RESIN-OBTURATED

ROOT CANALS

Mohamed I. Elshinawy1

Corresponding author email: dr_shinawy@hotmail.com

Contributor:

1Assistant professor of Endodontics

Department of Endodontics, Faculty

of Dentistry, Tanta University, Egypt

and Department of Restorative

Dental Sciences, College of

Dentistry, King Khalid University, Abha, Saudi Arabia

ABSTRACT

Background: Apical seal helps preventing apical leakage following apicectomy.

Aim: To investigate the influence of apicectomy modalities on apical seal of root

canals obturated with resin-based system. Materials and Methods: Root canals of

60 extracted premolars were prepared and obturated in 6 groups using RealsealSE

sealer-points system. The teeth were divided into 6 equal groups according to

apicectomy procedures. Group1 (obturation, immediate apicectomy, glass-ionomer

retro-filling), Group2 (obturation, apicectomy after 24 hours, no retro-filling),

Group3 (obturation, immediate apicectomy, light-curing of the sealer at the cut-

surface), Group4 (obturation, immediate apicectomy, no apical-sealer light-curing),

Group5 (apicectomy, obturation, apical-sealer light-curing), Group6 (apicectomy,

obturation, light-curing of apical sealer coat). Specimens in all groups were

subjected to dye leakage and longitudinal sectioning test. The collected data were

statistically analyzed. Results: Both G1 (control) and G6 recorded comparable

leakage possibility that was the lowest among test groups. Leakage values of groups

3 and 5 were also comparable and lower than groups 2 and 4. Leakage values of

group 4 were the worse among all groups. Conclusion: Apical sealing with a self-

etch adhesive sealer coat is an acceptable alternative to retrograde filling in resin-

obturated canals. Light-curing of the sealer exposed following apicectomy might improve the apical seal.

Key words: apicectomy, adhesive sealers, leakage, retrograde filling

INTRODUCTION:

Management of the resected root end during

periradicular surgery is critical to a successful

outcome.(1) The goal of periradicular surgery is to

access the affected area, remove the diseased tissue,

and place a biocompatible seal. This sealing material

should stimulate cementum deposition and re-

establishment of periodontal attachment as a desired

healing response. (2) Resection of the root end results

in an exposed dentinal root face surrounded

peripherally by cementum with a root canal in the

middle. Favorable healing response is characterized by

a biological seal formed by cementum fill from the

circumference of the resected root-end to the center

added to the physical seal of the root end filling

forming a double seal. (3)

An ideal root-end filling material should promote

periradicular tissue healing through its tolerability and

adherence to retrograde cavity walls. (4, 5)

Too many solid and plastic filling materials have been

used for retro-grade cavity filling. Solid fillings

include silver, tin and titanium posts, amalgam and

gallium alloys. Plastic fillings include sealers such as

calcium hydroxide and epoxy resin sealers and

cements such as zinc phosphate, polycarboxylate,

ZOE, IRM, Super EBA, MTA, calcium phosphate,

Journal of Dental & Oro-facial Research Vol 12 Issue 1 Jan 2016 JDOR

MSRUAS 4

bone cements and gutta-percha. Composite resin is

also commonly used as a retro-filling material.

Ceramic inlays, teflon, a mixture of sulfathiazole and

powdered dentin, cyanoacrylates, citric acid

demineralization and laser are less commonly used

alternatives.(6- 11) Glass ionomer showed good

marginal sealing capacity in vitro, and has been found

to offer excellent biocompatibility.(12,13) Compomers

has been proved to have better biocompatibility than

ordinary glass ionomer cements and MTA and was

suggested as the material of choice in root resorption,

perforations, and root-end filling.(14)

There has long been a debate on whether a root-end

filling should always be placed to achieve a better

apical seal. (15-18) So, this in vitro study was conducted

to investigate the influence of different apicectomy

modalities on the apical seal of root canals obturated

with Realseal SE sealer-points system

Materials and Methods

Sixty single-canaled human mandibular premolars

with straight root canals, freshly extracted from

persons with age group 20 to 45 years old were

selected for this study. Teeth were radiographed to

ensure root integrity and canal patency and then stored

at room temperature in physiological saline solution.

Teeth with immature apices, cracks, and caries were

excluded from the study. Soft tissue remnants and

calculus were removed using ultrasonic scalers. The

teeth were decoronated using a diamond disc (Edenta

AG, AU/SG, Switzerland) under water cooling to

standardize the remaining root length to 16 mm. The

working length was established using #15 K-file

(Dentsply, Maillefer, Ballaigues, Switzerland). The

file was introduced through root canals until its tip was

visible at the apical foramen. The actual working

length was then determined to be 1mm shorter than the

length of the used file.

All root canals were prepared with a series of k-files

using step back technique. The apical preparation was

standardized to master apical file # 40 and the stepping

back procedure was continued till K-file # 60. The

coronal flaring was done using gates glidden drills

(Union Broach, New York, NY) size 1,2&3. During

root canal preparation, 2ml. of 2.5% sodium

hypochlorite solution was used for irrigation after each

file. After canal preparation, the root canals were

conditioned with 10 ml of 17% EDTA (Canal +,

Septodont, France) for 60 seconds for smear layer

removal, followed by washing using 10 ml of 5.25%

NaOCl. Finally root canals were flushed with 10 ml

saline solution and dried with paper points (Dentsply-

Maillefer, Ballaigues, Switzerland).(19)

Grouping

The prepared roots were thereafter randomly divided

into 6 groups (n=10) according to the modality of

apicectomy procedures.

G.1 (control) - G.4: Realseal Self-Etch sealer /

Realseal point obturation was done first followed by

resection of the apical 3mm of the roots.

Size 40 master Realseal point (0.02 taper) was

seated to check the tug-back into the prepared canal

and confirmed with periapical radiograph. To

standardize the consistency of the sealer,

predetermined amount, 1cm long, of the self-etching

adhesive Realseal SE sealer (SybronEndo, Basicweg ,

Amersfoort, The Netherlands) was thoroughly mixed

with one drop of thinning liquid on a graduated mixing

pad. The master cone was used to apply the mixed

sealer against the prepared canal walls using slight

pumping motion twice before seating the cone to the

full working length. Lateral condensation was carried

out using a finger spreader (Dentsply, Maillefer,

Ballaigues, Switzerland). The rest of the canal space

was filled with laterally condensed auxiliary Realseal

points. The excess points were cut off using a heated

hand plugger (Dentsply, Maillefer, Ballaigues,

Switzerland) followed by vertical condensation.

Excess sealer was removed with alcohol-soaked

cotton pellet. A check radiograph was then taken to

ensure complete canal filling and the coronal surface

of the obturation was light cured using a curing light

(Hilux LED 550; Benlioglu Dental, Ankara, Turkey)

with an output of 1000 mW/cm2 for 40 seconds to

create an immediate coronal seal. After root canal

obturation, their apical 3mm were resected using a

high-speed handpiece with water coolant and a fissure

bur (Dentsply/Maillefer). The resected root-ends were

smoothed with a double-sided carborundum disk

(Dentorium Export Ltd, New York, NY, USA).(20 , 21)

and received different kinds of treatments as follows:

G.1(control): the root resection was done immediately

after obturation followed by preparation of a small

cavity at the apical end of the root canal by a rotating

# 4 slow speed round bur (Dentsply/Maillefer) to 2mm

depth into the canal followed by filling this cavity with

compoglass F (Ivoclar Vivadent AG,

Schaan/Liechtenstein).(22) (Fig. 1,2)

G.2: obturation, apicectomy after 24 hours, no further

apical treatment.

G.3: obturation, immediate apicectomy, light-curing

of the sealer exposed at the cut-surface.

G.4: obturation, immediate apicectomy, no further

apical treatment.

G.5 & G.6: surgical resection of the apical 3mm of

the root was done first followed by RealSeal Self-

Etch sealer / Realseal point obturation using the

Journal of Dental & Oro-facial Research Vol 12 Issue 1 Jan 2016 JDOR

MSRUAS 5

same technique with the only exception that the

extruded realseal points through the resected

apices were cut off using a hot hand plugger.

In G.5: the sealer exposed at the cut root surfaces was

thereafter light-cured.

In G.6: a thin sealer coat was thereafter rubbed over

the cut root surface using a small brush followed by

light curing (Fig. 3).

Fig. 1: Digital radiograph showing resected root apices(a), retrograde cavity depth(b) & root end filling(c)

Fig. 2: Retrograde Cavity Before & After Filling

Fig.3 Resected root with apical sealer coating

Fig 4: Removal of root canal filling (a) & root canal and root end filling (b)

Leakage testing

Root surfaces were coated with two layers of nail

varnish except the apical 2 mm. The apex of each

resected root was subsequently immersed uprightly in

freshly prepared 2% methylene blue dye solution for

72 hours at 37 ˚C. (23)

Teeth were then rinsed in tap water to remove

excess dye, nail varnish was removed with scalpel

blade and two longitudinal grooves were prepared on

the lingual and buccal surfaces of each root with a

diamond disc under water-cooling. Each root was then

split longitudinally into two halves using a chisel and

hammer. The teeth were then dried, coded and the root

fillings were removed to detect the maximum coronal

linear dye penetration from the apical cut end in both

halves of each split root (Fig.4). (24) Maximum linear

dye penetration was measured in mm using a

graduated ruler and a magnifying lens.

Statistical analysis: The mean values of apical leakage of experimental

groups with the standard deviation were calculated and

analyzed statistically using 1-way analysis of variance

(ANOVA). Sceffe’s test was performed to pick up the

site of statistical significance at α =0.05. Furthermore,

Tukey’s comparisons at α =0.05 was done to stand on

the significance of differences between test groups.

RESULTS

The mean leakage measurements and their statistical

values were shown in tables 1 and 2. One-way

ANOVA test indicated some differences in the leakage

parameter between the test groups (p= 6.24E-22).

Additionally, Tukey’s comparisons indicated that both

G1 (control) and G6 recorded comparable leakage

possibility (p=0.4332). The leakage values of both

groups were proved to be the lowest in comparison to

other test groups. The leakage values of groups 3 and

5 were also comparable (p=0.4332) and lower than

Journal of Dental & Oro-facial Research Vol 12 Issue 1 Jan 2016 JDOR

MSRUAS 6

groups 2 and 4. Leakage values of group 4 were the

worse among all groups.

DISCUSSION The purpose of retrograde sealing after

apicectomy is to establish an effective barrier between

the root canal and the periapical tissues.(25)

In the current study, all the root canal preparation and

obturation procedures were standardized and done by

the same operator to decrease variability. Sodium

hypochlorite was used as a canal irrigant because of its

lubricant, antimicrobial, organic tissue dissolving

properties (26) but was not used as the final rinse as it

may affect the sealer-dentin bond strength.(27) Smear

layer was removed to allow deeper resin sealer

penetration into dentinal tubules thus improving the

adhesion.(28) Root canals were obturated with realseal

points/realseal SE sealer (SybronEndo, Basicweg ,

Amersfoort, The Netherlands) that was previously

marketed as Resilon-epiphany SE system (Pentron

Clinical Technologies LLC, Wallingford, CT) which

is a resinous material claimed to give monoblock

obturation. Some in vitro and in vivo studies (29, 30)

proved an acceptable resistance of Epiphany sealer to

bacterial leakage. It was also reported that this material

can reinforce the obturated roots minimizing the

chances of vertical root fracture.(31)

Realseal SE has been tried as an apical seal in

group 6 of the current study based on the finding that

adhesives are usually used over composite retro-

fillings for better sealability.(32) The self-etch

adhesives were also found less time consuming and

TABLE (1): The mean and standard deviation for different groups

Group 1 2 3 4 5 6

1 0.000145* 0.0003* 0.000145* 0.000145* 0.4332

2 14.82 0.000155* 0.000145* 0.006293* 0.000145*

3 6.891 7.93 0.000145* 0.4332 0.04583*

4 24.36 9.535 17.46 0.000145* 0.000145*

5 9.535 5.287 2.643 14.82 0.0003*

6 2.643 12.18 4.248 21.71 6.891

* Significant (sig.) difference at P ≤ 0.05

less technique sensitive with better sealability.(33) In

addition, Maltezos, et al., 2006(34) observed good

sealing results for Resilon and concluded that it might

be used as retrograde filling material.

Compoglass F retro-filling was used as a control

in this study as it has been proved to have better

biocompatibility than ordinary glass ionomer

cements and MTA and was suggested as the

material of choice in root resorption,

perforations, and root-end filling. (14)

Root resection of 3 mm from root tip was done

perpendicular to its long axis of the tooth as this

reduces the apical ramification and lateral canals, thus

decreasing the number of open dentinal tubules and

leakage at the resected root end. (35- 38) The retro-cavity

was prepared 2mm in depth to ensure effective light-

curing of compoglass retrofilling.(39)

Methylene blue dye linear penetration &

Longitudinal sectioning of roots were performed for

measurement of microleakage in this study as it

enables the direct observation of the dye penetration

and its penetration pattern. (40) Also Methylene blue

has a comparable molecular size to those small

bacterial metabolic products, rapidly detected under

visible light, water soluble, diffusible and hard tissue

non-reactive. (41-43) The recommended times of

exposure to dyes in leakage studies have ranged from

2 hours to 30 days. (40) In our investigation the teeth

were left in the dye solution for 72 hours.(23)

Groups Mean ± SD

G.1 obturation - Immediate apicectomy - compoglass retrograde filling 1.5± 0.43

G.2 obturation - apicectomy after 24hrs- no further treatment 3.2± 0.39

G.3 obturation-Immediate apicectomy - apical light curing of exposed sealer 2.3± 0.38

G.4 obturation - Immediate apicectomy- no further treatment 4.3± 0.36

G.5 apicectomy – obturation - curing of the exposed sealer at the cut surface 2.6± 0.29

G.6 apicectomy - obturation + cut surface coating with SE sealer - curing 1.75± 0.18

Table 2: Tukey’s pair wise comparisons:

Journal of Dental & Oro-facial Research Vol 12 Issue 1 Jan 2016 JDOR

MSRUAS 7

The results of this study showed comparable

sealability for both G.1 (obturation, immediate

apicectomy and compoglass retrograde filling) and

G.6 (apicectomy, obturation and coating the cut

surface with SE sealer). These results were supported

by findings of some previous studies which showed

that, the direct application of a retrograde root seal

may eliminate the need for preparing a retrograde

cavity that might be difficult to prepare due to the

limited access to the surgical field.(44) Also it has been

shown that preparing and filling a small concavity on

the resected root face with composite resin and dentin

bonding agent (26) or light cure glass ionomer cement (45,46) gave acceptable (44) and even better (45,46) sealing

ability than retrograde filled cavities. In addition, open

dentinal tubules at the beveled root surface of

apicectomized teeth may invite leakage and the

authors advocated complete coverage of the resected

surface with an adhesive retro-seal regardless the

angle and extent of the bevel thus blocking these

dentinal tubules.(47) Moreover, Tanomaru-Filho et al.,

(48) had come to a conclusion that, Epiphany may be an

alternative as a retro-filling material.

The results also showed that both of G.3

(obturation, immediate apicectomy and apical light

curing of exposed sealer) & G.5 (apicectomy,

obturation and curing of the exposed sealer at the cut

surface) are comparable to each other. This might be

referred to the fact that each of them has a good chance

for good condensation of realseal points and hence less

sealer exposure at the apex and also get the benefit of

light curing at the periapical area which accelerates the

polymerization and sealer bonding to both the realseal

points and the root dentin.

The better results for both G3 and G5 (light

curing was done to the sealer at the exposed apical root

end) compared to both G2 and G4 (no light curing to

the sealer at the exposed apical root end) may be

referred to the fact that the light curing improve the

sealing through the formation of hybrid layer at the

dentin-resin sealer interface. This is supported by the

results of a study done by Hashimoto et al (49) who

concluded a superior dentin sealing of a self-etch

adhesive resin due to the retained hybridized smear

plugs within the tubules. (50)

G.2 (obturation, apicectomy after 24hrs with no

further treatment) showed less than expected sealing

ability because of some suggested reasons. The first is

that this dual-cure resin sealer depends mainly on its

chemical-cure components for polymerization in the

apical region and the second is that the cutting stresses

at the apex might have interrupted the apical bond

between the sealer and the dentin wall resulting in

more leakage.

This is supported by previous findings that

proved that mechanical interruption of the

sealer/realseal point /root dentin bond with a rotating

cutting instrument might affect their apical seal.(51)

Additionally, despite the hybridization of resin-filling

materials, a tight seal is difficult to achieve because of

the complex anatomy and mechanical challenges such

as polymerization shrinkage and unfavorable C-factor

inside the root canals.(52)

The least leak-proof results was for G.4

(obturation, immediate apicectomy with no further

treatment) which might be due to the obvious fact that,

the chemical curing reaction takes too much time

compared to light activated cure giving a chance for

sealer degradation and more leakage and this was

confirmed by a study of Beriat et al, 2009(53) who

came to a conclusion that, the amount of conversion of

Epiphany was approximately 50% after photo-

activation and improved by approximately 10% after

15 days. These results indicated weak polymerization

of uncured Epiphany which supports our results.

From the previous studies, it is clear that further in

vivo histologic and microleakage studies are needed to

assess the healing pattern(s) of the periapical tissue

following the application of different treatment

modalities suggested by the current study.

Conclusion:

Under the circumstances of this study we can conclude

that, apical sealing with a self-etch adhesive sealer

coat is an acceptable alternative to retrograde cavity

filling in apicectomized roots obturated with resin-

based system. Light-curing of the sealer exposed

following apicectomy might improve the apical seal.

Conflict of interest

The author declares no conflict of interest

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