Written by Trish Jones, RDH, BS Monday, 09 May 2011 14:28
The evolution of technology has had a profound effect on dentistry. Advances in dental materials to progressive innovations in clinical techniques make dentistry more efficient, aesthetic, and even kinder to the patient. Dental hygienists can learn how to better add value to their contributions to the operation of the dental office once they realize the benefits and features of the newer dental materials. They can communicate more clearly how today's dentistry can look better, be stronger, and hopefully last longer than the dentistry of the past! It is to the practice's advantage if team members are well-versed in all aspects of current dental materials and techniques. While the focus on more comprehensive care has embraced updated concepts such as the oral systemic link of health, the registered dental hygienist (RDH) can be a crucial member of the dental team to introduce and discuss restorative treatment options with the patient. Proper restorations can help facilitate a healthy periodontal condition, as well as other positive key factors.
IT TAKES A TEAM
In today's unsettled economy, the modern dental practice truly needs "all hands on deck," with every team member being capable of not only handling their clinical duties, but helping patients to understand and appreciate the many great services that their doctor and team can do for them. The dental hygienist, because of his or her trusted position as a caregiver, has a unique opportunity to add value and to enhance treatment acceptance, for the benefit of the patient and the practice.
Dental practices have to become savvy to uphold treatment and care of existing patients to maintain productivity. Downsizing employee personnel in the dental practice is not uncommon. Cross training existing employees to be more proficient in discussing treatment options to patients can help maximize productivity through a higher case acceptance. The trust factor for patients is often a result of the rapport and caregiver position developed by the dental assistants, front office personnel, and the RDH. The hygienist has the opportunity to reassure the patient of the creditability of the treatment offered by the dentist. That is, if the RDH has the needed knowledge (well-rounded continuing education choices are important) and confidence to be able to discuss the latest aesthetic restorative options, and the dentist is also up-to-date and capable of meeting those demands. The modern dental practice will be so much further ahead when all team members understand and can communicate the many benefits that dentistry is able to offer!
The utilization of the hygienist, as an integral team member who is trained to discuss restorative treatment options with patients, can be a huge benefit to everyone involved. Among the these are increased job satisfaction for the RDH, a higher level of rapport with patients that will enhance case acceptance, the process of a team approach that can lead to increased office efficiency/productivity, and the reduction of stress levels for the dentist.
|Patient presented with discolored and worn teeth. Case restored with leucite-reinforced porcelain (IPS Empress Esthetic [Ivoclar Vivadent]). |
Dentistry courtesy of Dr. Michael Reece of Bryan, Texas. Laboratory work fabricated by Bob Clark and his team at Williams Dental Laboratory, Gilroy, Calif.
Of course, much of this also depends on having a hygienist who shares the same philosophy of practice and the same practice objectives. Hygienists are educated professionals who can take the time (when deemed appropriate and given adequate time) to educate and discuss treatment options for periodontal and/or restorative work during re-care appointments. It is an optimal opportunity to talk with the patient in which a trusting relationship has already been established. It should not be viewed as "selling" dentistry, or making a diagnosis (the doctor's role). It is simply to play a greater role in supporting the practice and educating the patient.
Dental hygienists have established interpersonal communication skills as well as clinical skills for preventive and therapeutic treatment modalities. The patient's confidence will be increased when the knowledge level of the dental office team is perceived as high, and if questions can be answered by not only the dentist, but by office and clinical team members as well. Not all team members feel confident in discussing treatment options. This is sometimes due to a lack of continuing education courses (ones dealing with appropriate topics), product knowledge, motivation to learn, dentist encouragement, or confidence in the dentist.
Dentistry is in constant evolution. New products, updated techniques, and modern advancements are constantly being introduced, and it can be a challenge for the dentist to stay current, let alone team members. Dentists should review the office vision and mission statement and disseminate dental materials knowledge so hygienists will know what current products are being offered at the practice. It is essential to know what the practice offers in terms of alternatives to amalgam and PFM restorations. Does the office offer lithium disilicate restorations? Can they be bonded, cemented, or both? What about zirconia restorations? Does the office offer thin veneers? What are the things patients need to know about thin veneers? Patients are becoming very tech-savvy and often do their own research online before coming to a dental or medical office. They arrive wanting the most value for the hard-earned money they will spend, and that includes a desire to have the best products available.
It is really not necessary to know the exact chemical makeup of the products offered or the details of the actual hands-on technique, but the basic why of one product over another. For instance, if you have a patient that is a grinder and has a broken down tooth, but prefers a tooth-colored crown, what might be the best choice: a leucite-reinforced, lithium disilicate, or zirconia restoration? What about composite? Does the office offer computer-aided design/computer-aided manufacturing (CAD/CAM) technology? Which one is strongest and most resistant to fracture? What material might present with the best chance for longevity and aesthetics, as well as patient satisfaction? Again, these decisions are also ultimately made by the doctor and laboratory team in the process of treatment planning a case, after a diagnosis is made. However, it is very beneficial for the entire team to know more about dental materials so that they can offer up support of any discussions occurring between the doctor and the patient. After discussions with the doctor (and after the doctor leaves the room), patients will often turn to the team member present and begin to ask more questions about a treatment plan. It is a real benefit for any team member to be able to properly and confidently reiterate or clarify what the doctor and the patient discuss regarding the treatment plan.
Since the introduction of adhesive dentistry, aesthetic dentistry has boomed. In the preadhesive era, successful cementation was dependent on resistance form and mechanical retention. Glass ionomer, resin-reinforced glass ionomer, and composite resin cements (and their associated adhesive materials and tooth-restoration techniques) introduced the era of chemical retention. Regardless of the adhesive material chosen, if the bonding protocol is not followed correctly, it can lead to an array of complications that can include marginal leakage with staining, tooth sensitivity, recurrent decay, debonding of the restoration, or even loss (complete debonding) of the restoration. Done correctly, bonding can strengthen the restoration and the tooth.
Adhesive dentistry includes using a bonding agent and a luting composite. Later generation bonding agents require one-step protocol as they contain both the primer and adhesive. Luting cement/composite is available in self-curing, light-cured, and dual-cured versions (some resin cements are self-etching and self-bonding) and come in a variety of shades or values. This can be critical in matching a thin veneer to existing natural dentition. It is crucial to follow the manufacturers' instructions, regardless of what product is chosen to maximize results and to prevent any adverse issues that can compromise the long-term integrity of the restoration. Continuing education courses are available to study these topics further and are highly recommended for the doctor and team since adhesive dental products are constantly evolving.
Let's continue now with a discussion of the types of aesthetic restorative materials available today.
Composite resin restorative materials have improved drastically over the past years and are being used more today than ever before. Composite resin restorative materials can be used for direct (in-office) and indirect (fabricated in a dental laboratory) restorations and consist of a resin base with varying percentages and varying shapes and sizes of glass filler particles. Depending on the type of composite, the formulations will vary; this allows them to be designed for different restorative uses. Both are bonded to the natural tooth structure and can be more minimally invasive in their preparation design when compared to full-coverage crowns. Direct inlays or onlays fabricated by a clinician chairside with composite resin exhibit a greater amount of polymerization shrinkage (typically 3% to 5%) than indirect composites. There is less shrinkage in indirect composites because the polymerization shrinkage occurs during the curing process on the laboratory bench prior to bonding the restoration into the tooth with a very thin layer of a luting resin. This virtually eliminates many of the short- and long-term problems associated with polymerization shrinkage usually in relation to placing direct composite resin restorations (microleakage, stress on the dentin walls, etc). It should be noted that manufacturers are working hard on reducing the shrinkage associated with direct composite resin materials (and have been successful in reducing it to as low as 3%), but to date, greater shrinkage still occurs when compared to the indirect composite technique.
Composite resins are mechanically polished to a shine. Depending on the patient's oral care habits, these restorations may lose luster and polish over time. A hygienist who is properly trained in composite resin polishing techniques can help maintain and improve these restorations by polishing them periodically with aluminum oxide. Many composites (microfilled and nanofilled [particles less than 100 nanometers]) have been introduced that make polishing easier and, as a result, the restorations are maintaining their luster and polish longer.
Porcelain restorations have continued to evolve throughout the last decade. With high demand for both aesthetics and function, aesthetic restorations are being used for want-based dentistry and need-based dentistry. Patients needing to replace broken down amalgams and old (sometimes unsightly) PFMs are looking toward more aesthetic options. Options include pressed ceramics, which utilize a lost wax technique using ingots that are available in various opacities, translucencies, and shades. Ceramic restorations often have supra- or equigingival margins. Tissues irritated from less than ideally prepped and laboratory produced PFM margins have the ability to heal due to an increased biocompatibility with metal-free materials. CAD/ CAM technology allows for fabrication of strong restorations fabricated out of lithium disilicate or zirconium oxide, providing the clinician with even more choices of restorative materials. Hygienists should review current modalities of treatment from the offices they work in. In order to support the practice in presenting treatment plan options, it is important for the hygienist to identify materials in order to establish a treatment plan for hygiene maintenance. For instance, aluminum oxide may restore luster to a composite, but it will not do so for a porcelain restoration. To revive luster or shine on a porcelain restoration, a paste designed specifically to polish porcelain (embedded with diamond particles) is recommended.
Leucite-reinforced porcelains (such as IPS Empress Esthetic [Ivoclar Vivadent], Authentic [Jensen Dental]), and OPC [Pentron Ceramics]) have traditionally been used for veneers and crowns due to their high (translucent) aesthetic appearance. (A clinical example is provided in case 1, Figures 1 to 4.) Leucite-reinforced porcelain is not indicated for bridges of any type. The restorations are fabricated by using a lost wax technique, as well as restorations fabricated in lithium disilicate.
They can be pressed and then externally stained or they can be created in full contour and then cut back and layered with overlying porcelains to mimic natural tooth structure and translucency. The biaxial flexural strength of leucite-reinforced porcelain (not bonded to tooth structure) ranges up to 160 MPa (lithium disilicate can be up to almost 3 times the strength [see below]) and must be bonded to optimize its strength.1,2 What exactly does this mean? As compared to other porcelains, they are not as strong and may be able to fracture more readily depending on the patient's parafunctional habits (such as nocturnal bruxism or grinding).
|Patient presented with facial erosion and wear. Case was restored using lithium disilicate (IPS e.max Press [Ivoclar Vivadent]). |
Dentistry courtesy of Dr. Rick Coker of Tyler, Tex. Laboratory work done by Bob Clark and his team at Williams Dental Laboratory, Gilroy, Calif.
Lithium disilicate is currently utilized to fabricate a variety of restorations (a clinical example is provided in case 2, Figures 5 to 7). These restorations are created using either a lost wax pressed technology in ingots (such as IPS e.max Press [Ivoclar Vivadent], OPC 3G [Pentron Ceramics]) or with CAD/CAM technology by employing blocks (such as IPS e.max CAD [Ivoclar Vivadent]) that can be designed (virtual wax-up) and milled without the need of an actual physical wax-up. The cutback and layering techniques can be used if this material is pressed, or it can be easily made (pressed or CAD/CAM block) as a monolithic restoration with no layering porcelain added (just stained and glazed) for maximum strength. Lithium disilicate is a highly aesthetic material that also has high strength. It can be either cemented or bonded (bonding with a resin cement is preferred when there is minimal resistance and retention form in the preparation). Pressed lithium disilicate has flexural strength of 400 MPa and the CAD/CAM version has a flexural strength of about 360 MPa. What does this indicate? This aesthetic porcelain that has higher strength can be more resilient to the forces of occlusion (parafunctional habits) thus minimizing the chances for fracturing. Pressed lithium disilicate is a versatile material as it can be used for crowns, veneers, thin veneers, 3-unit anterior bridges, 3-unit premolar bridges and implant superstructures. Also because of the strength properties, lithium disilicate porcelains have the ability to be fabricated into very thin veneers (0.3 to 0.5 mm) that have exceptional aesthetic properties, thus enabling the dentist to use minimally invasive techniques (minimal- to no-preparation).1,2
Zirconia (Zirconium Oxide)
|Table. Features of Aesthetic Restorative Options|
Zirconia has evolved throughout the years and, with reported flexural strength of 900 MPa to 1,400 MPa (depending on the manufacturer), it is the strongest biocompatible ceramic material available. Substructures or cores can be fabricated (CAD/CAM) out of zirconia (such as Lava [3M ESPE], IPS e.max CAD, VITA In-Ceram Zirconia [Vident]), Cercon Zirconia [DENTSPLY Ceramco], Procera AllZirkon [Nobel Biocare], KaVo Everest [KaVo Dental], ZenoTech [Wieland], or Katana [Noritake Dental], to name a few) and can have layering porcelains pressed or traditionally over it for exceptional aesthetic properties. It has also been recently introduced for use as full contour (monolithic) zirconia (such as Pearl [Pentron Clinical Technologies] or BruxZir [Glidewell Laboratories]). CAD/CAM technology has also allowed the design and manufacturer of both the core and layering portions individually; then the core and layering porcelain are either subsequently fused in a porcelain oven (Lava DVS system [3M ESPE]) or, as with the VITA Rapid Layer Technology (Vident) system, bonded together with composite resin cements (such as RelyX Unicem [3M ESPE] or PANAVIA 21 [Kuraray]). Zirconia is indicated for full-coverage crowns, core materials for bridges and crowns, and abutments for implants. Restorations fabricated from zirconia can be cemented with conventional or resin cements (Table).3
New Impression and Manufacturing Methods
CAD/CAM has been widely accepted in other industries (such as in the medical and automotive). It has quickly become a manufacturing option in dentistry in both the dental laboratory and the dental office. CAD/CAM technology has allowed for precise fit and fabrication of restorations. The utilization of chairside systems has allowed restorations to be fabricated while the patient waits, or to have digital impressions sent via the Internet to the dental laboratory for fabrications of models and restorations. In-office systems allow for restorations to be designed and milled from a block, and conveniently delivered to patients on the same day with no second appointments needed; several systems also allow the clinician to scan in the preparations (digital impressions) and the file is sent electronically to the dental laboratory (such as CEREC AC [Sirona Dental Systems] or E4D [D4D Technologies].4
With the iTero (Cadent) and Lava C.O.S. (3M ESPE) systems (these do not allow for chairside milling [CAM] fabrication of the restorations), the digital impression taken in the dental office is sent electronically to the dental laboratory. There, the restorations are designed (CAD) and fabricated (CAM), then returned to the dental office for final insertion.
An integral member of the extended dental team is the dental technician, often not physically present in the office. Remember that your dental laboratory technicians are usually willing and able to share their knowledge and expertise related to the many indirect dental materials that they work with on a daily basis. Doctors should consider contacting them more often, as a regular part of the treatment planning process (before the handpiece is pulled out to begin preparation[s]). The dental laboratory team, when provided the proper information (models, photos, etc) can be extremely helpful in discussing the possibilities and in assisting hygienists in making dental material decisions.
USE OF ULTRASONIC SCALERS AND AIR POLISHING
It is important for hygienists to be aware of the damage that the use of ultrasonic energy can have on resin bonded crowns and different types of composites. The hygienist should also know exactly what type of existing restorations a patient has. Ultrasonic scalers should not be used in close proximity to these restorations because of potential damage to resin-tooth bonds (especially resin-dentin). Remember, one suggested technique to attempt removal of failed (resin-cemented) endodontic posts, as a conservative technique before actually attempting to cut them out, is to use bursts of ultrasonic energy with water as a coolant. Obviously, the injudicious use of ultrasonic energy and composite resin bonded restorations do not mix.
As for air-polishing protocol, usage should not be on composite, resin-reinforced glass ionomers, or on/near the margins of porcelain restorations at the resin-cement interface. Due to the abrasiveness, it can scratch, erode, pit, or cause leakage at the margins. The hygienist can inadvertently contribute to the loss of integrity and thus compromise the longevity of the aesthetic restoration. Air-abrasive powders originally included sodium bicarbonate and aluminum trihydroxide. Newer choices are available that include calcium carbonate, glycine, and calcium sodium phosphosilicate. The use of glycine produces the least amount of roughness on the surface of restorations. Calcium sodium phosphosilicate is a bioactive glass, also known commercially as NovaMin (Sultan Healthcare). The relative abrasiveness of this material has not been studied, although it has shown effectiveness in desensitizing and remineralizing natural tooth structure. The key point to note is if air polishing is used around resin-bonded porcelain restorations, the margins should be completely avoided to circumvent irrevocable damage. Air polishing should not be used on composite materials. If the hygienist has further concerns about a specific air-polishing agent being used, refer to the manufacturer's instructions before proceeding with air polishing and reevaluate the necessity of utilizing the air polisher.
Case acceptance is dependent upon the knowledge base of not only the dentist, but the entire dental office team. Ultimately, it is up to the dentist(s) (practice owner[s]) to ensure that all team members know the value of, and truly believe in, the services being offered. As a part of accomplishing this, the clinician(s) should take the steps necessary to ensure that the whole team is fully educated on the basics of the dental materials being used every day in the practice. Most importantly, all team members must have the trust and belief that their dentist(s) can meet or exceed all treatment expectations with the best interest of the patients in mind. Doing all these things, and doing them well, will propel optimal case acceptance.
The hygienist is a key cohesive team member to discuss not only periodontal treatment options with the patient but restorative possibilities as well. With the focus on comprehensive care and maintenance, the hygienist has amazing opportunities to contribute to the success of not only a healthy smile, but to be rewarded with the chance to offer an added-value benefit for the patients and the dental practice.
- Terry DA, Leinfelder KF, Geller W. Aesthetic & Restorative Dentistry: Material Selection & Technique. Houston, TX: Everest Publishing Media; 2009:144-157, 158-163.
- McLaren EA, Whiteman YY. Ceramics: rationale for material selection. Compend Contin Educ Dent. 2010;31:666-670.
- Giordano R, Sabrosa CE. Zirconia: material background and clinical application. Compend Contin Educ Dent. 2010;31:710-715.
- Miyazaki T, Hotta Y, Kunii J, et al. A review of dental CAD/CAM: current status and future perspectives from 20 years of experience. Dent Mater J. 2009;28:44-56.
Disclosure: Ms. Jones is a key opinion leader with Ivoclar Vivadent and a trainer with cadent iTero but does not receive compensation.