More Than Just Bond Strength: Clinical Success Is a Multifaceted Endeavor
While clinical studies are an important factor in the selection of dental materials, successful adhesive dentistry involves more than simply choosing materials with the best clinical bond strengths. Practitioners must also consider such issues as consistency, ease of use, and predictability to ensure proper clinical usage.
In 2009 I was honored to give a presentation in Dubai, UAE, on the recent advancements in cosmetic dentistry and dental adhesives. I was a young dentist with 4 years of clinical experience and was just beginning to understand some of the nuances of dentistry. Within the first hour of my presentation a doctor stood up in the room and yelled, “Where is the science?,” claiming that the presentation was merely “pretty pictures” and clinical slides. He wanted to know where the science was to back up my claims and the studies to prove that what I was saying actually worked. He proceeded to pack his bag and walk out of the lecture. He was right—I didn’t have the science and clinical studies in my lecture because I didn’t really understand them at that time. I was using the materials that seemed to work best in my hands rather than the ones that showed the best clinical studies.
The experience made me realize that dentists use materials for different reasons based on what is most important to them. Some choose materials based on cost. Others choose materials for predictability, ease of use, and number of steps needed in the procedure. Some dentists choose materials based on “the science” and published clinical studies. While clinical studies are an essential aspect in choosing materials, there are also other factors to consider. A number of recent advancements are impacting dentistry and changing the way clinicians provide treatment.
Evolution of Bonding Agents
Bonding has progressed over the years. There have been several different generations of bonding agents introduced to the market as the technology has advanced.1 This progression, which is briefly summarized in Table 1, has culminated with what are called universal bonding agents, which are currently very popular. These materials are resolving much of the confusion dentists face regarding adhesive dentistry by simplifying and streamlining the bonding process.
In today’s fast-paced world, there is an emphasis on getting things done better and faster with a minimal amount of effort. This seems to be the driving force behind much of the change in dental practice. Before switching to a universal bonding agent, the author’s practice utilized several different bottles of bonding agents from three of the different generations. Often, they would get mixed up, be used incorrectly, or expire before they could be used. Now, with the universals, it is easier to maintain one system for all bonding needs. For example, the same bonding agent used on direct restorations is the one used to cement crowns, place a post inside of a tooth, or perform a simple Class V restoration. The universal bonding agent has simplified the restorative process in the author’s practice and has eradicated confusion.
Universal bonding agents offer versatility, as they can be used in self-etch, selective-etch, and total-etch modes, and can also be used with all forms of curing lights. They can be light-cured or dual-cured, and will also self-cure on their own without a light. Lastly, they can adhere to all major dental materials, enabling them to streamline systems, decrease postoperative sensitivity, and achieve excellent bond strengths at the same time. Examples of commonly used universal bonding agents include OptiBond™ XTR (Kerr Dental, www.kerrdental.com), All-Bond Universal® (Bisco, www.bisco.com), and Scotchbond™ Universal (3M ESPE, www.3MESPE.com). Universal bonding agents continue to grow in popularity due to their simplicity and ease of use.
Bulk-Fill Composites Increase Speed, Efficiency of Direct Resins
As bonding agent protocols are getting simplified, composite placement techniques are also trending to faster and more convenient ways of filling direct restorations. Clinicians have mostly been educated to restore teeth by isolation and layering composites in four to five layers when filling a tooth.2 The thought of backfilling the entire restoration at once is a concept that has taken time to prove itself, because it goes against clinicians’ basic instincts when performing direct resin restorations. Now, however, several large product manufacturers are selling their version of a bulk-fill composite. Some of the options include SonicFill™ (Kerr Dental), Surefil® SDR® flow and QuiXX® (DENTSPLY, www.dentsply.com), and Tetric EvoCeram® (Ivoclar Vivadent, www.ivoclarvivadent.com). With its distinctive handpiece delivery system, SonicFill is unique in that it allows rapid flow of posterior composite into the cavity for effortless placement while still allowing for proper sculpting of the resin.
Easy-to-Clean Resin Cements
Resin cements are becoming more appealing because of the current trends in self-etching/priming cements, eliminating the need for a separate etching step. While studies still show that better bond strengths can be obtained by etching and placing a dental bonding agent separately, the self-etching cements are still proving to be very effective.3 Undoubtedly, the most important part of the indirect restorative procedure is ensuring proper cementation and sealed margins. While resin cements have always done this well, one of the downsides had traditionally been cleaning up excess resin after cementation. This changed several years ago with the introduction of resin cement (NX3, Kerr Dental) that became known for its easy clean-up. Its success led to other products (eg, Panavia™, Kuraray, www.kuraraydental.com; Multilink®, Ivoclar Vivadent) being released that offer easy clean-up options. With this development, now the most important part of the restoration process no longer has to be the most stressful part.
Approaches to Consider
Regarding adhesive dentistry, there are several approaches that can help guide a clinician’s strategy. First, if the current method being used in the practice is working, then stay with it. There will always be improvements made to bonding agents, with higher bond strengths or better properties. What is most important in quality dentistry is predictability. If a clinician is using a total-etch technique and is seeing more postoperative sensitivity than he or she would like, then it might be worth switching to a self-etching alternative. If microleakage is a problem and there are issues with restorations debonding, then it may be prudent to switch to a selective-etch or total-etch technique. The key is for the clinician to find not only what is clinically proven but also what works well in his or her hands.
The next tactic is to educate the dental team regarding bonding systems. Inform them about the various systems available and why they are different. Discuss the importance of following manufacturers’ instructions and having good systems in place. Create predictable systems for the team to use.
Finally, while, as mentioned earlier, it may be practical to continue using a system you’re comfortable with, it is important to be open to learn new techniques and adapt to change. Walking the halls of conferences and meetings such as the recent International Dental Show (IDS) in Cologne, Germany, can help clinicians witness firsthand the advancements and changes that are imminent in the dental industry. Clinicians should embrace change and look for opportunities to grow in their profession.
While the “science” of dentistry is unequivocally vital, consistency, predictability, and ease of use are also factors that must be considered for successful dentistry. Moreover, regardless of the advances in technology and product development, clinicians must take the time to follow the proper protocol in the procedures they are performing everyday and continually educate themselves with the aim of improving clinically.
1. Farah JW, Powers JM, eds. Bonding agents. Dental Advisor. 2008;25(5):1-9.
2. Mackenzie L, Shortall AC, Burke FJ. Direct posterior composites: a practical guide. Dent Update. 2009;36(2):71-80.
3. Barcellos DC, Batista GR, Silva MA, et al. Evaluation of bond strength of self-adhesive cements to dentin with or without application of adhesive systems. J Adhes Dent. 2011;13(3):261-265.
About the Author
Brian Harris, DDS
International Lecturer and CEREC® Trainer
2007 Hornbrook Group Scholarship for being named Young Dentist of the Year