Clinical Excellence by Mark L. Cannon, DDS, MS

Dentaltown Magazine

Universally providing the correct shade for posterior composite restorations

by Mark L. Cannon, DDS, MS

Perhaps one of the biggest challenges confronting new dentists is the ongoing and increasing pressure to compromise on patient care. In the past, there were far fewer options, with silver amalgam or gold being the foremost restorative materials, followed by the advent of resin-based composite materials.1 Because of pioneers in adhesion principles, aesthetic dentistry was born, ushering in the age of true artistry in cosmetic dentistry, with journals depicting the many stunning possibilities in patient care.2,3 Sadly, not all of these procedures are covered by dental insurance policies, but patients do desire to have what appears to be a healthy and young dentition. Wanting to look attractive to their peers is often stated to be a motivating factor in the younger population.4 For instance, a traumatically fractured incisor normally prompts adolescents and young adults to quickly see their dental practitioner.5 Unfortunately though, not all patients have acceptable coverage for their basic dental needs and, quite frankly, economic pressures are mounting for government-funded dental programs to reduce overhead costs.6 A sad consequence of this drive to reduce costs has been the overutilization of silver amalgam, because it is considered more economical than resin-based composites.

Silver amalgam is also often placed in special-needs patients,7 with the explanation that these patients aren’t as aware of aesthetic needs, which thus are less important than speed of treatment. This is opposed to the concept that all patients deserve respect, and cost of care needs to be carefully considered, not arbitrarily determined by a third party.8 Other means can be used to reduce overhead costs. One such overhead cost is the need to maintain an inventory of numerous shades of dental resin-based composites, some that are rarely used and yet, necessary to provide the best in cosmetic care.

Resin-based composites are the backbone of restorative dentists’ armamentarium.9 However, placing a resin-based composite restoration requires more operator time than silver amalgam and certainly requires isolation to prevent adhesion bond contamination.10

Resin-based composites have several key areas of concern in clinical practice. One is the adhesive bond, which can be subject to contamination and void formation.11 Another is the longevity of the hybrid layer, plus underpolymerization of the resin component that’s also reportedly a substantial issue, especially for microleakage and cytotoxicity.12–14 Regardless, the days of silver amalgam being “king” appear to be long gone, especially with the United States’ ratification of the Minamata Convention.15* Arguably, the resin-based composite is now the new “king” of dental restorative materials, because current products have substantial improvements over previous composite materials. One such improvement has been the introduction of bulk-fill materials, such as Estelite Bulk Fill Flow from Tokuyama Dental, which limit the need to incrementally fill the cavity preparation. Another such improvement is the introduction of a “universal shade” resin-based composite that is truly universal and blends with any shade dentition.

Case Study
The patient, a 13-year-old male, presented with sensory sensitivity issues, concerned over the look of mercury fillings, which he had heard from friends would turn his tooth black. He also expressed concern over being able to return to school without looking different and having his face droopy. His anxieties were based both on experiences his friends had reported and their comments on social media (something new for dentists to be aware of). Upon an earlier recare examination it was revealed that the defective, hypoplastic and hypomineralized maxillary first molar had become sensitive and carious. Because of the multiple shades of enamel present in the hypomineralized defect and his concern over a perfect shade match, Omnichroma composite from Tokuyama Dental was chosen as the resin-based composite restorative material.

After the application of topical anesthetic (20 percent benzocaine gel) into the sulcus of the molar, single tooth anesthesia from Milestone Scientific was administered using 3?percent carbocaine without a vasoconstrictor (Fig. 1). Vasoconstrictors are not necessary when using intraligamentary injections because the anesthetic solution normally remains within the ligamentary space. The molar was then isolated with a rubber dam (Fig. 2) and was cleansed by pumice prophylaxis and rinsed (Fig. 3). The molar was then prepared for an occlusal restoration with a high-speed turbine handpiece and #330 carbide bur with adequate water spray (Fig. 4).16

Caries removal was completed with a #4 round bur in a slow-speed handpiece and then spoon excavator, keeping the dentin moist to reduce postoperative sensitivity.17 Keeping the dentin moist during preparation reduces the amount of smear layer formed.

After removal of the infected dentin, the enamel margin was etched for 30 seconds and then the dentin for three seconds (Fig. 5, above, and Fig. 6, p. 74). Copious water flow was utilized to thoroughly remove the etchant and the etching debris. Excess moisture was removed with high-volume suction only. The moist dentin was bonded using Tokuyama Universal Bond, which self-polymerizes and does not require light initiation (Figs. 7 and 8, p. 74). The Omnichroma resin-based composite was placed in 2-millimeter-thick increments that were individually light-cured for 20 seconds each (Fig. 9). An amalgam condenser may additionally be used to pack the resin-based composite if need be (Fig. 10). The final fill was placed, and the gross anatomy refined with a lateral condenser, also known as an acorn burnisher (Fig. 11). Polishing was accomplished with a Raptor bur from Bisco and spiral-fluted carbide finishers. The rubber dam was removed and the occlusion marked for adjustment (Fig. 12). After final adjustment, the resin-based composite restoration was additionally light-cured to enhance the wear resistance and increase surface hardness.18, 19.

The patient was very pleased with the appointment, especially the perfect shade matching of the restoration and the lack of facial “numbing” (Fig. 13). As in this case, it seems that the aesthetics of even posterior composites have become increasingly important for our patients. There is a need for aesthetic, natural-appearing restorations and for durable restorations that are not in competition with each other, but rather a desirable combination. The availability of a new restorative material with the capability of blending in difficult situations— especially in economically depressed regions of the world—is beneficial to many. In the situation of providing dental care to very young, less than fully cooperative patients, or to those with special needs and unable to cooperate, the universal shade-matching ability of Omnichroma is very beneficial.

On a very positive note, I have not noticed any “white line” formations in the Omnichroma restorations I’ve placed thus far. White line formation occurs because of the high polymerization stress that occurs during light initiation of resin-based composites. Many techniques have been advocated to prevent or reduce the marginal fracturing of the adjacent enamel that produces the “white line” effect.20 But the most efficacious method for the dental practitioner to reduce this polymerization stress would be for the restorative material to have a low Young’s modulus, allowing for flexural dissipation of the stress energy.21 The lack of the “white line” and the perfect shade blending of the Omnichroma restorations are both very positive aspects of this new resin-based composite material.

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*The Minamata Convention on Mercury is an international treaty designed to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds.
Location: Kumamoto, Kumamoto Prefecture, Japan
Depositary: Secretary-General of the United Nations
Signed: 10 October 2013
Signatories: 128
Effective: 1
6 August 2017

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Author Bio
Author Mark L. Cannon, DDS, MS, is a professor of otolaryngology in the dentistry division of the Feinberg School of Medicine at Northwestern University, an attending physician at Ann and Robert Lurie Children’s Hospital and a member of the International Association of Pediatric Dentistry. In addition to being the founder of Associated Dental Specialists of Long Grove, Cannon is the research coordinator of the pediatric dental residency program at Ann and Robert Lurie Children’s Hospital. Cannon, who has 40 years of experience in pediatric dentistry, has lectured nationally and internationally on many oral health topics, including evolutionary oral medicine, the gateway microbiomes, biologic and bioactive dental materials (patents owner), probiotics, and all aspects of everyday pediatric oral health. Cannon has accepted two invitations from the Karolinska Institutet in Sweden to the Nobel Forum (2016) and the Nobel Assembly (2017).


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