very technique sensitive

Fifth Generation

That request ushered in the fifth-generation bonding sys

-

tems, introduced during the mid 1990s, which combined

primer and adhesive in one bottle while maintaining high

bond strengths. Products in this category include Excite

(Ivoclar Vivadent), OptiBond

®

Solo Plus™ (Kerr), Prime

and Bond

®

NT (Dentsply), and Adper™ Singlebond™

(3M ESPE). Unit-dose packaging introduced during this era

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provided fresh chemistry for each procedure. Yet controlled

etching, surface wetness, and resin placement continued to

be a clinical challenge for some clinicians.

Sixth Generation

The sixth-generation bonding systems introduced in the

latter part of the 1990s and the early 2000s—also known as

the “self-etching primers”—were a dramatic leap forward in

technology. The separate acid-etching step was eliminated

by incorporating an acidic primer that was placed on the

enamel and the dentin after tooth preparation.

Several vari

-

ations involved either mixing the acidic primer and adhesive

before placement on the dentin and enamel, or leaving the

primer on the tooth and then placing the adhesive over the

primer. Some products in this class are Clearfil

®

SF Bond

(Kurarray), Simplicity™ (Apex), Adper™ Prompt™, and

L-Pop™ (3M ESPE). These systems were also reported to

reduce the incidence of post-treatment sensitivity found in

previous systems.

However, the bond strength to dentin

and enamel is lower than fourth- and fifth-generation sys

-

tems

(Table 1).

Ideal Bonding Agent Attributes

Attributes of an ideal bonding agent would include high

bond strength, a thin film thickness to ensure easy and com

-

plete seating of restorations, shelf stability, and post-place

-

ment stability. The ability to release fluoride is desirable to

help prevent the onset of secondary caries, which is the lead

-

ing reason for replacement of existing restorations.

In addi

-

tion, the bonding agent should be user-friendly—ideally a

one-step procedure requiring no mixing, with the versatility

to be used for multiple types of restorations (indirect and

direct, resin/ceramic, and metal), and tolerant of both moist

and dry environments (Table 2).

Table 2. Ideal Bonding Agent Attributes

High bond strength

Thin film thickness

Fluoride-releasing

User-friendly

Suitable for moist and dry environments

Stability

Seventh Generation Bonding Systems

The latest category, seventh-generation bonding systems,

is the “all in one” adhesives that combine etch, prime, and

bond in a single solution.

This adhesive category was intro

-

duced in late 2002. Laboratory studies show bond strengths

and margin sealing to be equal to sixth-generation systems.

Products in this category include iBond™ (Heraeus), Xeno

®

IV (Dentsply), G-Bond™ (GC), Complete (Cosmedent),

and OptiBond

®

All-In-One (Kerr).

Both OptiBond All-

Table 1. Evolution of Bonding Adhesives

1960s and 1970s First and Second Generation

Did not recommend dentin etching.

Relied on adhesion to smear layer.

Weak bond strength.

1980s Third Generation

Acid etching of dentin.

Separate primer.

Increased bond strength.

Margin staining caused clinical failure over time.

Early 1990s Fourth Generation

Acid etching of dentin.

Separate primer.

Increased bond strength.

Margin staining caused clinical failure over time.

Early 1990s Fourth Generation

“Hybrid” layer of dentin and collagen.

Dentin seal.

Concept of “wet bonding” introduced.

Technique sensitive.

Mid 1990s Fifth Generation

Combined primer and adhesive in one bottle.

Maintained high bond strengths.

Unit-dose packaging introduced.

Late 1990s, Early 2000s Sixth Generation

“Self-etching” primers.

Reduced incidience of post-treatment sensitivity.

Bond strengths lower than fourth- and fifth-generations.

Late 2002 Seventh Generation

“All-in-One”.

Combines etching, priming and bonding.

Single solution.

Good bond strength and margin sealing.

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in-One and Xeno IV are fluoride releasing, while iBond and

G-Bond are not.

The all-in-one adhesives are user-friendly, and most

offer both a bottle and a unit-dose version. There are varia

-

tions on other attributes depending on the product used.

Shear bond strength, a key attribute in dental adhesives,

varies considerably depending on the self-etch adhesive

used. (Figure 1)

Xeno IV self-etch seventh generation adhesive is avail

-

able in a bottle or unit dose delivery and does not require

mixing. Xeno IV is pH balanced to reduce gingival irritation

and sensitivity. Clearfil S3 Bond, G-Bond and iBond are

available in a bottle. Clearfil S3 Bond contains water to alle

-

viate the need for a surface with a specific degree of wetness

and to resist hydrolysis, providing for a lasting and reliable

adhesion. It resists hydrolysis which provides for reliable

and durable adhesion.. As with other seventh-generation

adhesives, G-Bond offers versatility in the degree of wetness

on the tooth surface at the time of ahdesive application.

The all-in-one seventh generation adhesives

are user-friendly and most offer both

a bottle and a unit-dose version

All-In-One Bond Dental Adhesive System

OptiBond All-In-One is a single-component, self-etch

adhesive that eliminates multiple steps when bonding di

-

rect and indirect restorations. Clinicians have everything

they need for etching, priming and bonding in one mate

-

rial. OptiBond All-In-One is a light-cured adhesive that

provides adhesion to all surfaces and substrates. Its ternary

solvent system provides enhanced shelf-life stability and ef

-

fective enamel etching for long-term bond performance.

According to some independent studies provided by

Kerr Corporation, OptiBond All-In-One delivers excellent

Figure 2. Etched Enamel

Figure 3. OptiBond All-in-One Adhesive-Dentin-Bonding Interface

Figure 4. Preoperative View of Smile

Figure 5. Preoperative Retracted View

Figure 1. Shear Bond Strength – All-In-One Adhesive Systems

Shear Bond Strength, MPa

Enamel

Dentin

OptiBond®

All-in-One

Xeno® IV

Clearfil®

S3 Bond

G-Bond™

iBond™

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penetration into dentin tubules, offering exceptional bond

strength and protection against microleakage and post-

operative sensitivity.

Its unique etching capability enables the most effective

enamel etching of any single-component adhesive, creating

a deeper-etched surface for higher mechanical retention and

chemical bonding. Scanning electron microscopy (SEM) of

etched enamel shows the deep etching obtained using this

capability (Figure 2), and SEM of the adhesive-dentin-

bonding interface shows the deep tags that result from use

of this system in dentin (Figure 3).

I have found that the low film thickness makes it easier

to seat indirect restorations, creating a better fit. OptiBond

All-In-One is available in both a 5 ml bottle delivery and a

convenient free-standing Unidose™ device.

OptiBond All-in-One offers exceptional bond

strength and protection against microleakage

and post-operative sensitivity

Case Presentations

Seventh Generation Bonding Agents are ideal for bond

-

ing indirect restorations, and for direct composite resin

(where bonding is mandatory regardless of the material

and technique being used).

Case Presentation 1 —

Indirect Restorations

A patient sitting for an initial consultation was dissatisfied

with her smile (Figure 4). Clinical examination revealed a

Maryland bridge from teeth #6–#8 with failing margins

(Figures 5, 6). The patient stated that the bridge had been

recemented a couple of times since its original placement

five years prior. Tooth #10 had an existing veneer restora

-

tion to correct a peg lateral. Also, tooth #11 and tooth #12

were inverted. Probing depths were within normal levels in

the anterior region, and the patient’s periodontal health was

within acceptable limits.

The

Smile Guide Book

(Discus Dental) was used to

complete the smile analysis necessary for predesigning the

case. Her existing bridge was asymmetric, and the patient

preferred a more complete and uniform smile. In order to

achieve this, the shape selected would be rounder and the

embrasures between the teeth would be smaller. The lip line

edge versus the incisal edge of the teeth suggested that the

patient could tolerate lengthening of the incisal edges. The

results of the smile analysis, diagnostic study models, and

preoperative clinical photography were reviewed with the

patient to determine the desired treatment plan for improv

-

ing her smile and function. Since the patient’s complaint

was extreme dissatisfaction with the whole appearance of

her smile, it was decided to incorporate a metal-free bridge

Figure 6. Preoperative Palatal View

Figure 7. Preparations

Figure 8. Restorations

Figure 9. Loading of Veneers

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material (Lava™, 3M) for the missing lateral and porcelain

veneers on the adjacent teeth. The proposed treatment plan

of a zirconium bridge (Lava, 3M) from #6–#8 and porcelain

veneers from #9–#11 was reviewed with the patient, and

she was excited to start the treatment.

After anesthetic was administered, a diamond bur was

used to prepare the anterior teeth. It was very important to

adhere to the preparation guidelines for the zirconium bridge

in order to ensure functional and esthetic predictability. The

laboratory required a minimum of 0.8 mm reduction of the

facial walls and a minimum of 1.5 mm of incisal reduction.

Internal line angles were to be rounded, and a butt joint mar

-

gin was required (Figure 7). Also, an ovate area was created

in the gingiva at the pontic site of tooth #7 with an Odyssey

®

Laser (Ivoclar Vivadent) to create a more harmonious emer

-

gence profile for the pontic. Impressions were taken using a

quick-setting polyvinylsiloxane (PVS) impression material

(Take 1

®

, Kerr). These impressions, a bite registration, and

photos were then forwarded to the lab for fabrication of the

final restorations.

Provisionalization

A provisional restoration, which was significant to the

overall treatment, was made from an impression of a

composite mock-up. Using Fill-In™ (Kerr) temporary

material, this mold was quickly filled and placed on the

patient’s prepared dentition. Within a couple of minutes,

the temporary had cured and was ready for shaping. Gross

shaping and contouring were achieved using flexible discs

(OptiDisc™, Kerr). A flame-shaped fine diamond was

used to shape and trim the margins and embrasure spaces.

The next day, the patient returned for evaluation of size,

shape, color, and bite. Already, she exhibited excitement

and confidence with her provisional restorations.

Laboratory

During the laboratory phase, the full arch polyvinylsilox

-

ane impressions were used to pour up a master model on

which the restorations would be based. The master model

was segmented into individual dies that were trimmed and

pinned to determine the manner by which the final res

-

torations would integrate with the existing soft tissue. A

silicone incisal matrix of the provisional restorations was

created to guide the placement of incisal effects and edge

position in the subsequent ceramic buildup. In addition,

comprehensive color mapping ensured that the definitive

esthetic results would meet patient expectations.

Cementation

The patient was anesthetized and a nonlatex split-rub

-

ber dam was placed. Prior to try-in of the definitive

restorations to verify fit and shade, the provisional

restorations were removed and any remaining cement

was cleaned off the prepared dentition using Preppies

Paste. The restorations were tried in to verify marginal

fit, contour, contacts, and shade (Figure 8). Following

patient approval of the final restorations, the cementa

-

tion process was initiated.

The veneer restorations were treated with 37 percent

phosphoric acid for 20 seconds, rinsed, silanated, and

air dried for one minute. OptiBond All-in-One was ap

-

plied to the preparations with a scrubbing motion for 20

seconds. A second application was placed on the prepara

-

tions with a scrubbing motion for 20 seconds and then

gently air dried for five seconds with a medium force

of air. The adhesive was light cured for 10 seconds per

tooth. Since the film thickness of OptiBond All-In-One

Figure 10. Postoperative Retracted View

Figure 11. Postoperative Palatal View

Figure 12. Postoperative View of Smile

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adhesive is approximately 5 microns after curing, there

was no concern during the seating process.

NX3 Nexus

®

Third Generation (Kerr) light-cure resin

cement was applied to the veneer restorations (Figure 9).

The restorations were then placed on the prepara

-

tions and, while they were firmly held in place, a rubber

tip applicator removed all excess luting cement from the

margins. A thin layer of glycerin was then applied to the

margins to prevent the formation of an oxygen-inhibit

-

ing layer. The restorations were tacked at the gingival

margin. Once the veneer restorations were placed, the

bridge restoration was seated using Maxcem (Kerr)

resin cement.

While the restorations were still firmly held in place,

the restored dentition was flossed and any excess luting

cement was carefully removed. Once the majority of the

excess cement was removed, the restored dentition was

completely light-cured from both the facial and lingual

sides. Any residual cement was removed with a #15

scalpel and finished with a fine diamond and polishing

points. The occlusion was verified and adjusted. Overall

health and structure of the soft tissue and restorations

were very good. As seen in the postoperative photos

immediately after seating, the restorations exhibited a

nice esthetic look and the patient was extremely happy

(Figures 10–12). Also, upon review two weeks later, the

patient had no complaints of sensitivity.

Case Presentation 2 —

Direct Composite Restorations

A patient sitting for an initial consultation was concerned

about some sensitivity on the left-hand side in her upper

back teeth. Clinical examination revealed that the occlusal

amalgam restorations on tooth #14 and tooth #15 were

defective, with leaking margins. The two teeth also had

fractures adjacent to the amalgams, caries was evident,

and a mesial defect was present on tooth #15 (Figure 13).

All other teeth were clinically sound, there was no reces

-

sion present, the patient’s periodontal health was within

acceptable limits, and she had no other complaints.

After discussion on the available options utilizing

the DemoDent anatomical model (DemoDent PLLC),

the patient elected to have the restorations replaced with

bonded composite restorations. After anesthetic was

administered, diamond burs were used to remove the

defective amalgams and adjacent caries (Figure 14).

Upon removal of the amalgams, it was found that car

-

ies was present in the deepest regions of the preparations.

This was carefully removed using a slow-speed handpiece

with large round burs. The preparations were extended

to remove the caries in the palatal fissure regions, and to

prepare the mesial box in tooth #15. A sectional matrix

band (Garrison) was placed over the mesial margin of

tooth #15 in such a way that its position and shape would

Figure 13. Preoperative View of Amalgam Restorations

Figure 14. Amalgam Restorations Removed

Figure 15. Preparations with OptiBond All-in-One

Figure 16. Finished Composite Restorations

Questions

1. The technique of etching enamel with

phosphoric acid was first introduced to

dentistry by _________.

a. G.V. Black

b. Lindhe

c. Buonocore

d. none of the above

2. In 1999, approximately _________

direct resin restorations were placed.

a. 25 million

b. 46 million

c. 75 million

d. 86 million

3. The first- and second-generation

bonding agents used during the 1960s

and 1970s _________.

a. did not recommend etching the dentin

b. allowed dentin leakage with clinical margin stain

c. relied on adhesion to the attached smear layer

d. all of the above

4. Third-generation adhesive systems

were introduced _________.

a. in the 1960s

b. in the 1970s

c. in the 1980s

d. none of the above

5. Third-generation adhesive systems

_________.

a. introduced acid etching of dentin

b. decreased dentin margin failure

c. increased bond strength over first- and second-

generation systems

d. all of the above

6. Fourth-generation adhesive systems

formed a “hybrid” layer of collagen

and resin.

a. True

b. False

7. _________ and _________ described

the penetration of resin into dentin

as giving high bond strengths and a

dentin seal.

a. Fusayama; Buonocore

b. Nakabayashi; Haggar

c. Fusayama; Nakabayashi

d. none of the above

8. The idea of “wet bonding” was

introduced by _________.

a. Tanika

b. Kanca

c. Fujiyama

d. all of the above

9. An advantage of fourth-generation

adhesive systems over earlier adhesive

systems was that they significantly

reduced margin leakage.

a. True

b. False

10. A disadvantage of fourth-generation

adhesive systems was _________.

a. the complexity of multiple bottles and steps

b. the higher bond strength achieved

c. the very technique-sensitive nature of the system

d. a and c

11. Fifth-generation bonding systems

_________.

a. were introduced during the mid 1990s

b. combined primer and adhesive in one bottle

c. were used only to etch enamel

d. a and b

12. Unit-dose packaging was introduced

_________.

a. with third-generation adhesive systems

b. with fourth-generation adhesive systems

c. with fifth-generation adhesive systems

d. all of the above

13. The bond strength to dentin and

enamel of sixth-generation adhesive

systems

a. was higher than in fourth- and fifth-generation

adhesive systems

b. was lower than in fourth- and fifth-generation

adhesive systems

c. was equal to that in fourth- and fifth-generation

adhesive systems

d. a and b

14. Attributes of an ideal bonding agent

include _________.

a. high bond strength

b. thin film thickness, to ensure easy and complete

seating of restorations

c. post-placement stability

d. all of the above

15. The leading reason for replacement of

existing restorations is _________.

a. restoration fracture

b. secondary caries

c. discoloration of the restoration

d. all of the above

16. “All in one” adhesives combine

_________ in a single solution.

a. etch, bond, and restoration

b. etch, prime, and bond

c. water, etch, and prime

d. none of the above

17. Seventh-generation bonding systems

were introduced in _________.

a. 1999

b. 2001

c. 2002

d. 2004

18. _________ is a key attribute in dental

adhesives.

a. High pH

b. Shear bond strength

c. Marginal detection

d. all of the above

19. A ternary solvent system provides

enhanced shelf-life stability and effec

-

tive enamel etching for long-term bond

performance.

a. True

b. False

20. Penetration of an adhesive system into

dentin tubules _________.

a. offers protection against microleakage

b. offers protection against postoperative

sensitivity

c. offers exceptional bond strength

d. all of the above

21. Deep penetration of an adhesive into

dentinal tubules is evidenced on SEM

by _________.

a. areas of remineralization

b. deep resin tags

c. wider tubules

d. none of the above

22. Low adhesive film thickness makes it

easier to seat indirect restorations.

a. True

b. False

23. Adhering to the preparation

guidelines for zirconium bridges is very

important _________.

a. to ensure aesthetic predictability

b. to ensure that soft tissue does not need to be

retracted

c. to ensure functional predictability

d. a and c

24. An ovate area can be created in

the gingiva at the site of a pontic to

_________.

a. create a more harmonious emergence profile for

the pontic

b. reduce the amount of porcelain palatally

c. help reduce caries

d. none of the above

25. In the laboratory, a silicone incisal

matrix of provisional restorations can

be used to _________.

a. guide the placement of incisal effects

b. guide the placement of edge position in the

subsequent ceramic buildup

c. cut a corner

d. a and b

26. According to the article, veneer

restorations can be etched _______.

a. with 37 percent phosphoric acid for 20 seconds

b. with 57 percent phosphoric acid for 60 seconds

c. with lactic acid for 45 seconds

d. none of the above

27. All direct resin restorations are

candidates for dentin bonding.

a. True

b. False

28. All seventh-generation adhesive

systems are available in both bottle and

unit-dose versions.

a. True

b. False

29. Fluoride-releasing bonding agents are

designed to _________.

a. promote demineralization

b. help prevent secondary caries

c. increase salivary flow

d. all of the above

30. The versatility of seventh-generation

dental adhesives _________.

a. enables their use in both indirect and direct

restorations

b. provides excellent marginal seal

c. provides high bond strength

d. all of the above

Date: 2015-02-03; view: 1145