The advent of
Carla Cohn, DMD
IF YOU ARE A GENERAL DENTIST who cares for children, you are the rule rather
than the exception. In 2016, the number of dentists in the United States was
196,441.1 Of these, 155, 102 were general practitioners and 7,337 were pediatric
1 Given that the majority of children are treated in family practices, it is
imperative that general dentists remain current with advancing pediatric dental
technology. From preventive modalities to restorative materials, pediatric dentistry
has seen significant innovations in recent years. In my opinion, one of the most
revolutionary changes is the advent of the primary prefabricated zirconia crown.
Increasingly, parents and children are demanding better
esthetic restorations. These demands are described in a
study by Peretz and Ram,
2 while another study by Zimmer-man et al. documents changing parental attitudes toward
pediatric restorative materials.
3 As these studies and clinical
experience have shown, the demand for improved esthetic
restorative dentistry for children is here. General dentists
have the ability to supply that demand with the latest esthetic materials such as primary prefabricated zirconia
crowns. These crowns are made of excellent material, and
when combined with proper technique, they give dentists
the ability to restore anterior and posterior carious dentition
both functionally and esthetically.
Primary prefabricated zirconia crowns are available for
all primary teeth: molars, cuspids, and incisors. The following manufacturers supply primary prefabricated zirconia
crowns: Cheng Crowns, EZPedo/Sprig, Kinder Krowns, and
NuSmile. They are either milled (Cheng Crowns, EZPedo/
Sprig, and Kinder Krowns) or injection molded (NuSmile).
Zirconia as full coverage offers many advantages over
other materials. Zirconia offers flexural strength that is far
greater than that of natural tooth4 while wearing at a similar
5 Prefabricated zirconia crowns are autoclavable, allowing
for trial and error when choosing and fitting the correct size.
Fracture load studies from Townsend et al. show variances
in fracturability between manufacturers.
6 The differences
were found to be significant, but all required 5–10 times the
amount of force to cause fracture of the mean maximum
biting force of a 10- to 12-year-old child in the molar area.
Above all, these crowns offer full-coverage advantages,
and are by far the most esthetic alternative in full-coverage
primary dentition restoration available to date. They make
for a reliable and beautiful restorative option for full coverage for our pediatric patients.
The following case study is presented to illustrate the ease
of tooth preparation and crown cementation: A 5-year-old
patient presented with caries of her primary dentition.
The mandibular left primary molar required full coverage
due to a failed composite restoration and extensive decay (figure
1). Both the child and her mother
had a desire for a tooth-colored
restoration. A primary prefabricated
(NuSmile ZR) was
chosen as the restorative material
The steps for preparation and cementation were as
follows. First, local anesthesia was delivered. Second,
isolation was achieved with an isolation system (Isodry).
Third, preparation steps were undertaken: Occlusal
preparation was completed using a high-speed handpiece
with copious amounts of water and a coarse, long-tapered
diamond bur (NuSmile) to achieve an occlusal reduction
of 1. 5–2 mm. Circumferential reduction of approximately
15–20% was carried out using the same bur. In order to
visualize the completeness and evenness of the
preparation, a full circumferential reduction supragingivally
was completed at this stage. A subgingival preparation
was again completed using a high-speed handpiece with
copious water and a finer, more tapered diamond bur
(NuSmile). As required, a full subgingival reduction to
approximately 1. 5 mm depth was achieved, ensuring no
ledges and a smooth featheredge
margin ( figure 2). It was essential
that the crown fit passively and be
able to be seated completely
SCIENCE & TECH
Figure 2: Full
1. 5 mm depth