THE EFFECT OF THERMOCYCLING ON THE DURABILITY OF DENTIN ADHESIVE SYSTEMS

Young-Hoon Moon; Jong-Ryul Kim; Kyung-Kyu Choi; Sang-Jin Park

doi:10.5395/JKACD.2007.32.3.222

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Original Article THE EFFECT OF THERMOCYCLING ON THE DURABILITY OF DENTIN ADHESIVE SYSTEMS: Young-Hoon Moon, Jong-Ryul Kim, Kyung-Kyu Choi, Sang-Jin Park^,*; J Korean Acad Conserv Dent 2007;32(3):-235.
DOI: https://doi.org/10.5395/JKACD.2007.32.3.222
Published online: January 14, 2007

Department of Conservative Dentistry, Division of Dentistry, Graduate of Kyung Hee University

*Corresponding Author: Sang-Jin Park, Department of Conservative Dentistry, Division of Dentistry, Graduate of Kyung Hee University 1, Hoegi Dong, Dongdaemun Gu, Seoul, Korea, 130-702, Tel: 82-2-958-9335 E-mail: psangjin@khu.ac.kr

• Received: March 2, 2007 • Revised: April 24, 2007 • Accepted: April 30, 2007

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Abstract
REFERENCES
참고문헌

Abstract

The objectives of this study was to evaluate the effect of thermocycling on the μTBS (microtensile bond strength) to dentin with four different adhesive systems to examine the bonding durability.

Freshly extracted 3^rd molar teeth were exposed occlusal dentin surfaces, and randomly distributed into 8 adhesive groups: 3-steps total-etching (Scotchbond Multi-Purpose Plus; SM, All Bond-2; AB), 2-steps total-etching (Single Bond; SB, One Step plus; OS), 2-steps self-etching (Clearfil SE Bond; SE, AdheSE; AD) and single-step self-etching systems (Promp L-Pop; PL, Xeno III; XE). Each adhesive system in 8 adhesives groups was applied on prepared dentin surface as an instruction and resin composite (Z250) was placed incrementally and light-cured. The bonded specimens were sectioned with low-speed diamond saw to obtain 1 × 1 ㎜ sticks after 24 hours of storage at 37 °C distilled water and proceeded thermocycling at the pre-determined cycles of 0, 1,000 and 2,000. The μTBS test was carried out with EZ-tester at 1 mm/min. The results of bond strength test were statistically analyzed using one-way ANOVA/ Duncan's test at the α〈 0.05 confidence level. Also, the fracture mode of debonded surface and the interface were examined under SEM.
The results of this study were as follows;
1. 3-step total etching adhesives showed stable, but bond strength of 2-step adhesives were decreased as thermocycling stress.
2. SE showed the highest bond strength, but single step adhesives (PL, XE) had the lowest value both before and after thermocycling.
3. Most of adhesives showed adhesive failure. The total-etching systems were prone to adhesive failure and the single-step systems were mixed failure after thermocycling.
Within limited results of this study, the bond strength of adhesive system was material specific and the bonding durability was affected by the bonding step/ procedure of adhesive. Simplified bonding procedures do not necessarily imply improved bonding performance.
Keywords: Thermocycling; Bond strength; μTBS; Type of solvent; Total-etch; Self-etch

Figure 1.

Specimen preparation for microtensile bond testing. Composite bonding on dentin surface and vertical slice with 1 ㎜ thickness.

Figure 2.

Failure modes of the fractured specimens. A. adhesive failure, B. mixed failure, C. cohesive failure

Figure 3.

Multiple comparison of microtensile bond strength for each adhesive as thermocycling.

Figure 4.

Bar charts showing the microtensile bond strength according to thermocycling for each adhesive type.

A. 3 step adhesive, B. 2 step total-etching adhesive, C. 2 step self-etching adhesive, D. 1 step self-etching adhesive. Vertical bar means the statistical significance in same adhesive.

Figure 5.

Failure modes of the fractured specimens.

Figure 6.

SEM image of interfaces bonded with SM and fractured surfaces.

A,B. Immediate tested specimen. C,D. A specimen after 2,000 thermocycling.

The adhesive resin is not deeply infiltrated into dentinal tubules so that resin tags are blunt, but relative thicker hybrid layer are examined. There is no specific difference between both groups. Both fractured surfaces show adhesive failure at mainly the base of hybrid layer and tubules are occluded by fractured resin tags (HL: Hybrid Layer, C: Composite Resin, RT: Resin Tag, DT: Dentinal Tubule).

Figure 7.

The adhesive interfaces bonded with OS and fractured surface.

A. Immediate tested specimen. Hybrid layer was formed uniformly and resin tags were deeply infiltrated into dentinal tubules so that formed lateral braches. B. A specimen after 2,000 thermocycling. Note some gaps on the top of hybrid layer. C. Mixed failed surface that adhesive failure at the top or bottom of hybrid layer in upper side and cohesive failure of composite in lower side of micrograph (HL: Hybrid Layer, C: Composite Resin, RT: Resin Tag, DT: Dentinal Tubule).

Figure 8.

The adhesive interfaces bonded with AD.

A. Immediate tested specimen. Relative thin hybrid layer that was well integrated without defect was formed uniformly and resin tags were deeply infiltrated into dentinal tubules. B. A specimen after 2,000 thermocycling. Some broken resin tags below hybrid layer were observed though long tags were formed (HL: Hybrid Layer, C: Composite Resin, RT: Resin Tag, DT: Dentinal Tubule).

Figure 9.

SEM image of interfaces bonded with single-step adhesives.

A. Immediate tested specimen bonded with PL. Relative thicker hybrid layer was formed uniformly and well demarcated from adhesive layer and greater number of resin tags were deeply infiltrated into dentinal tubules that was connected each other by lateral braches. B. Fractured surface of PL after 2,000 thermocycling shows adhesive failure that peritubular dentin is remained partially. C. Adhesive failed surface of PL 2,000 group. Adhesive layer is a worm-eaten appearance that allows water movement between the interface and the underlying hydrated dentin. D. A specimen after 2,000 thermocycling. Note some gaps between adhesive layer and top of hybrid layer (HL: Hybrid Layer, C: Composite Resin, RT: Resin Tag, DT: Dentinal Tubule).

Table 1.

The 8 adhesives used in this study

Type	Adhesives(codes)	Composition	Application mode
3-step total etching systems		PrimerA:- NTG-GMA (N(p-tolyl)glycine-glycidyl	a, b1,
		methacrylate), acetone, ethanol, water	c1, e, f
		Primer B:
		BPDM (biphenyl dimethacrylate), photoinitiator, acetone
	All-Bond 2	D/E bonding resin:
	(AB)	Bis-GMA (bisphenol A glycidyl methacrylate),
		UDMA(urethane dimethacrylate), HEMA
		(2-Hydroxyethyl methacrylate),
		CQ (camphorquinone)
	Scotchbond	HEMA, Polyalkenoic acid copolymer,	a, b1,
	MP (SM)	Bis-GMA	c1, e, f
2-step total-etching- systems	One-Step (OS)	Bis-GMA, BPDM, HEMA, Acetone, CQ	a, d,
			c1, e, f
	Single Bond	Bis-GMA, HEMA, Bisphenol A glycerolate	a, d,
	(SB)	dimethacrylate, Water, UDMA, Polyalkenoic	c1, e, f
		acid copolymer, Ethanol
2-step self etching-systems	Clearfil SE	MDP (10-methacryloyloxydecyl dihydrogen phosphate),	b2, d,
	Bond (SE)	HEMA, N,N-Diethanol p-toluidine, water, Bis-GMA,	c2, e, f
		HEMA, N,N-Diethanol p-toluidine, microfiller, CQ
		Phosphoric acid ether acrylate, Hydrolytically stable	b2, d,
	AdheSE(AD)	bisacrylamide, Water, Initiators and stabilizers,	c2, e, f
		Bis-GMA, GDMA (glycerol dimethacrylate), HEMA,
		Highly dispersed silica filler
Single-step self-etching systems	Adper-	Water, stabilizer, parabenes, methacrylated phosphoric	e, d,
	Prompt	acid esters, fluoride complex, photoinitiator BAPO	c2, f
	L-pop (PL)	(bisacylphosphine oxide)
	Xeno III (XE)	Water, ethanol, HEMA, methacryloxyethyl-pyrophosphate,	e, d,
		F-releasing phosphazene, UDMA, micro-filler, CQ	c2, f

a - acid etch for 15 sec and rinse, b1 - primer, b2 - SEP (self-etch primer), c1 - moist surface properly, c2 - dry, d - dwell for 10 – 40 sec, e - adhesive, f - light cure (10sec, 600 mW/cm²

Table 2.

μTBS (㎫, mean ± SD) of each groups before and after thermocycling. Multiple comparison tests were performed within each adhesive type. Same superscript means no statistically difference in each adhesive type at α≤ 0.05 confidence level. TEA: Total etching adhesive, SEA: Self etching adhesive

Adhesive\Thermo cycling	3 step TEA		2 step TEA		2 step SEA		1 step SEA
Adhesive\Thermo cycling	SM	AB	OS	SB	SE	AD	PL	XE
Immediate	34.4 ± 14.4	36.4 ± 12.8	36.9 ± 14.2^c	36.5 ± 9.9^c	48.5 ± 10.2^D	34.1 ± 16.6^B	24.1 ± 8.4^γ	22.4 ± 7.2^γ
1,000 cycles	39.1 ± 11.1	32.1 ± 15.3	33.0 ± 14.1b c	28.4 ± 7.4^ab	44.4 ± 15.0^CD	25.1 ± 6.3^A	21.7 ± 7.9 βγ	15.5 ± 6.9^αβ
2,000 cycles	35.3 ± 15.0	29.6 ± 12.6	26.4 ± 10.4^ab	21.0 ± 8.2^a	36.5 ± 10.1^BC	28.0 ± 7.2^AB	18.7 ± 6.9 αβγ	13.5 ± 9.7^α

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THE EFFECT OF THERMOCYCLING ON THE DURABILITY OF DENTIN ADHESIVE SYSTEMS

J Korean Acad Conserv Dent. 2007;32(3):222-235. Published online January 14, 2007

DOI: https://doi.org/10.5395/JKACD.2007.32.3.222

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Figure

THE EFFECT OF THERMOCYCLING ON THE DURABILITY OF DENTIN ADHESIVE SYSTEMS

Figure 1. Specimen preparation for microtensile bond testing. Composite bonding on dentin surface and vertical slice with 1 ㎜ thickness.

Figure 2. Failure modes of the fractured specimens. A. adhesive failure, B. mixed failure, C. cohesive failure

Figure 3. Multiple comparison of microtensile bond strength for each adhesive as thermocycling.

Figure 4. Bar charts showing the microtensile bond strength according to thermocycling for each adhesive type.

Figure 5. Failure modes of the fractured specimens.

Figure 6. SEM image of interfaces bonded with SM and fractured surfaces. A,B. Immediate tested specimen. C,D. A specimen after 2,000 thermocycling. The adhesive resin is not deeply infiltrated into dentinal tubules so that resin tags are blunt, but relative thicker hybrid layer are examined. There is no specific difference between both groups. Both fractured surfaces show adhesive failure at mainly the base of hybrid layer and tubules are occluded by fractured resin tags (HL: Hybrid Layer, C: Composite Resin, RT: Resin Tag, DT: Dentinal Tubule).

Figure 7. The adhesive interfaces bonded with OS and fractured surface.

Figure 8. The adhesive interfaces bonded with AD.

Figure 9. SEM image of interfaces bonded with single-step adhesives.

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

Figure 9.

THE EFFECT OF THERMOCYCLING ON THE DURABILITY OF DENTIN ADHESIVE SYSTEMS

Type	Adhesives(codes)	Composition	Application mode
3-step total etching systems		PrimerA:- NTG-GMA (N(p-tolyl)glycine-glycidyl	a, b1,
		methacrylate), acetone, ethanol, water	c1, e, f
		Primer B:
		BPDM (biphenyl dimethacrylate), photoinitiator, acetone
	All-Bond 2	D/E bonding resin:
	(AB)	Bis-GMA (bisphenol A glycidyl methacrylate),
		UDMA(urethane dimethacrylate), HEMA
		(2-Hydroxyethyl methacrylate),
		CQ (camphorquinone)
	Scotchbond	HEMA, Polyalkenoic acid copolymer,	a, b1,
	MP (SM)	Bis-GMA	c1, e, f
2-step total-etching- systems	One-Step (OS)	Bis-GMA, BPDM, HEMA, Acetone, CQ	a, d,
			c1, e, f
	Single Bond	Bis-GMA, HEMA, Bisphenol A glycerolate	a, d,
	(SB)	dimethacrylate, Water, UDMA, Polyalkenoic	c1, e, f
		acid copolymer, Ethanol
2-step self etching-systems	Clearfil SE	MDP (10-methacryloyloxydecyl dihydrogen phosphate),	b2, d,
	Bond (SE)	HEMA, N,N-Diethanol p-toluidine, water, Bis-GMA,	c2, e, f
		HEMA, N,N-Diethanol p-toluidine, microfiller, CQ
		Phosphoric acid ether acrylate, Hydrolytically stable	b2, d,
	AdheSE(AD)	bisacrylamide, Water, Initiators and stabilizers,	c2, e, f
		Bis-GMA, GDMA (glycerol dimethacrylate), HEMA,
		Highly dispersed silica filler
Single-step self-etching systems	Adper-	Water, stabilizer, parabenes, methacrylated phosphoric	e, d,
	Prompt	acid esters, fluoride complex, photoinitiator BAPO	c2, f
	L-pop (PL)	(bisacylphosphine oxide)
	Xeno III (XE)	Water, ethanol, HEMA, methacryloxyethyl-pyrophosphate,	e, d,
		F-releasing phosphazene, UDMA, micro-filler, CQ	c2, f

Adhesive\Thermo cycling	3 step TEA		2 step TEA		2 step SEA		1 step SEA
Adhesive\Thermo cycling	SM	AB	OS	SB	SE	AD	PL	XE
Immediate	34.4 ± 14.4	36.4 ± 12.8	36.9 ± 14.2^c	36.5 ± 9.9^c	48.5 ± 10.2^D	34.1 ± 16.6^B	24.1 ± 8.4^γ	22.4 ± 7.2^γ
1,000 cycles	39.1 ± 11.1	32.1 ± 15.3	33.0 ± 14.1b c	28.4 ± 7.4^ab	44.4 ± 15.0^CD	25.1 ± 6.3^A	21.7 ± 7.9 βγ	15.5 ± 6.9^αβ
2,000 cycles	35.3 ± 15.0	29.6 ± 12.6	26.4 ± 10.4^ab	21.0 ± 8.2^a	36.5 ± 10.1^BC	28.0 ± 7.2^AB	18.7 ± 6.9 αβγ	13.5 ± 9.7^α

Table 1. The 8 adhesives used in this study

a - acid etch for 15 sec and rinse, b1 - primer, b2 - SEP (self-etch primer), c1 - moist surface properly, c2 - dry, d - dwell for 10 – 40 sec, e - adhesive, f - light cure (10sec, 600 mW/cm²

Table 2. μTBS (㎫, mean ± SD) of each groups before and after thermocycling. Multiple comparison tests were performed within each adhesive type. Same superscript means no statistically difference in each adhesive type at α≤ 0.05 confidence level. TEA: Total etching adhesive, SEA: Self etching adhesive