Practice Solutions: Tokuyama Dental by Dr. Carla Cohn

Header: Primary Care
by by Carla Cohn, DMD

Pediatric dentists are both scientists and artists when creating functional and aesthetic restorations. What's more, they must master and perform procedures in limited time frames—and in often inhospitable environments—as well as managing the behavior of not just the patients but also the children's parents.

In pediatric restorative dentistry, which has so many physical and behavioral variables, your technique and material choice must be dependable. To increase the success rate of your procedures, develop an armamentarium of the most reliable dental materials. Composite resins, introduced almost half a century ago, make up a large part of the restorative materials market in North American dentistry.1

Case study: Composite restoration with modified snowplow technique
A case study of a composite restoration on upper right second primary molar follows with a modified snowplow technique.2 3 4 After the patient was anesthetized, the tooth was isolated with rubber dam, in a traditional slot-type fashion. A composite restoration presents several challenges, including the hydrophobic nature of the material. Care must be taken to properly isolate the teeth to maintain a dry field; for this reason, cooperation of our young patients is paramount, and isolation is imperative.5

A high-speed, friction-grip, straight flat-end cross-cut bur (Brasseler carbide #556) is used to establish outline form and the majority of the preparation. For a successful restoration, outline form must be conservative, and diligence in preserving sufficient tooth structure is essential. Decay is removed with a slow-speed, latch-angle round bur (Brasseler carbide #6 and #8).

Mechanical retention is created with a slow-speed, latch-angle inverted cone (Brasseler carbide #35); this is important because primary teeth have thinner enamel, and many children experience continued bruxing and occlusal wear.

A Triodent clear metal sectional matrix, wave-wedge and V3 ring are placed. The initial image (Fig. 1) shows preparation and matrix with excellent adaptation to the gingival margin, mesial and distal of the proximal box.

The preparation is etched for 10 seconds with a selective etch technique, washed and dried, then Tokuyama Dental adhesive Bond Force is applied and light-cured. A small increment—approximately 10 percent fill—of Tokuyama's Estelite Flow Quick is placed (Fig. 2), followed by final placement, in bulk, and shaping and curing of Tokuyama's Estelite Sigma Quick (Fig. 3). The restoration is finished and polished.

Fig. 1

The fill and the fix
The demand for aesthetic, functional restorations is already widespread—and still on the rise. The industry has developed many restorative materials but in pediatric dentistry, reliability and ease of use are the most necessary attributes for a composite resin. I think that Estelite Sigma Quick is one of the superior composites on the market. A universal "supra-nano" (average particle size of 200 nanometers6) filled composite, it has two unique properties that make it stand above other composite materials:

Spherical filler technology allows for beautiful handling characteristics of the material including simplified shade match, ideal wear, easy polishing and low volumetric shrinkage. Fillers that are spherical and of uniform size allow for light diffusion and "blur," and blend readily into surrounding tooth structure, making shade-matching much more forgiving.

The spherical fillers are silica oxide and zirconia oxide, which allow for lower composite wear and less wear of the opposing dentition, which is an important feature for primary enamel. Polish time is decreased because the spherical filler is easily and quickly polishable to a high luster.7 Estelite Sigma Quick also has a low volumetric shrinkage of 1.3 percent and high filler content—82 percent by weight, 71 percent by volume—to withstand bruxing and wear. Low shrinkage and high fill content equate to decreased postoperative sensitivity and less marginal breakdown and leakage. This is very significant because the primary reasons for failure of composite restorations are secondary caries and marginal deficiencies.8, 9, 10

Rapid action polymerization (RAP) is the initiating system of polymerization for the material. In RAP, the energy from photo polymerization is transferred to radical amplifiers in the material, which then react with monomers to create multiple polymers. (It's like a flash mob, where one person begins, the excitation expands to a few nearby people, and the process continues and compounds.) Because polymerization process is sped up, photo cure can occur much more rapidly. A higher increase in the depth of cure than conventional resin-based composites has been proven with prolonged irradiation time.11 Estelite Sigma Quick also is not as sensitive to ambient light as most composite materials, so a working time of 90 seconds is available with no slump, to handle the material before polymerization will begin with surrounding light. The RAP "flash mob" ensures a reliable cure in a short time, balanced by the extended work time in ambient light.

Fig. 2 Fig. 3 Fig. 3 Fig. 4 Fig. 4 Fig. 4
The properties of Estelite Sigma Quick are ideal for pediatric restorative dentistry's unique requirements. Restorative materials used for children must be strong and durable. Primary teeth are unique in the wear and tear that they endure in a short period of time, whether from bruxing or the indiscriminate chewing of Lego pieces. Children are hard on their dentition—and sometimes hard on their dentists. With all of the challenges that you face, your techniques and materials shouldn't be among them. Choose your technique and material wisely, and success should follow.

  1. Christensen G J, Making Class II resin-based composite restorations predictable and profitable. JADA Vol. 141 April 10: 457 - 460.
  2. Olmez A, Oztas N, Bodur H. The effect of flowable resin composite on microleakage and internal voids in class II composite restorations. Oper Dent. 2004 Nov-Dec;29(6):713-9.
  3. Simi B, Suprabha B J. Evaluation of microleakage in posterior nanocomposite restorations with adhesive liners. Conserv Dent. 2011 Apr;14(2):178-81.
  4. MR Saijan GS, BNK Mittal N. Effect of different placement techniques on marginal microleakage of deep class-II cavities restored with two composite resin formulations. J Conserv Dent. 2010 Jan;13(1):9-15.
  5. AAPD Clinical Guidelines, Guideline on Restorative Dentistry, Reference Manual V 36 / NO 6, 14 / 15
  6. Lu H, Lee YK, Aguri M, Powers YK, Properties of a Dental Resin Composite with a Spherical Inorganic Filler. Operative Dentistry, 2006, 31-6, 734-740
  7. Marghalani, HY Effect of filler particles on surface roughness of experimental composite series. J Appl Oral Sci. 2010;18(1):59-67
  8. Hickel R, Kaaden C, Paschos E, Buerkle V, Garcia-Godoy F, Manhart J, Longevity of occlusally stressed restorations in primary teeth. Am J Dent, 2005, Jun:18(3):198-211.
  9. Manhart J, Chen H, Hamm G, Hickel R, Buonocore Memorial Lecture. Review of the clinical survival of direct and indirect restorations in posterior teeth of the permanent dentition. Oper Dent, 2004 Sep-Oct; 29(5) : 481-508.
  10. Kohler B, Rasmusson CG, Odman P. A five-year clinical evaluation of Class II composite resin restorations. J Dent 2000;28(2): 111-116.
  11. Ilie N, Keppel I, Durner J, Effect of radical amplified photo polymerization (RAP) in resin based composites. Clinical Oral Investigations May 2014, Issue 4, pp 1081 - 1088.

Dr. Carla Cohn Dr. Carla Cohn is a general dentist who devotes her practice solely to children's dentistry and maintains a private practice at Kids Dental in Winnipeg, Manitoba, Canada. Cohn's clinical articles have been published in several North American dental journals, and she is an international speaker on pediatric dentistry for the general practitioner.

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