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very technique sensitiveFifth 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 www.ineedce.com 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. www.ineedce.com 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™ www.ineedce.com 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 www.ineedce.com 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 www.ineedce.com 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: 2014
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