the metal facing after cementation and replac- ing it with a tooth-colored material.21 Placement of these crowns is technically challenging and time consuming, however. Preveneered SSCs (PVSSCs) were introduced approximately 20 years ago. In a survey by Oueis et al,13 41% of respondents selected PVSSCs as their first choice for restoring anterior primary teeth. Esthetically pleasing, the crowns earn high levels of parental satisfaction.22–24 Unlike SSCs, the fitting of PVSSCs should be passive, as any forceful placement or excessive pressure could cause the white facing to break, crack or chip.7 Only slight crimping of the lingual surface should be used for margin adaption and retention, but minimal adjustment of the lingual margin does not seem to decrease facial veneer facture resistance.25 Several retrospective stud- ies have demonstrated the high retention rates of PVSSCs.22,23,26,27 FUTURE DIRECTIONS The biggest issues with these crowns are fracture and loss of some, or all, of the veneer — which is challenging to repair.22–24 Consequently, PVSSCs should also be avoided in patients with anterior crossbites or where occlusion precludes their use. ZIRCONIA CROWNS Recently, prefabricated zirconia crowns have become available in various sizes to fit every primary tooth. Some brands also offer a nar- rower version of canines and first primary molars for patients with space loss or crowd- ing. These monolithic crowns are made of solid zirconia, so there is virtually no possibility of facial veneer fracture.28,29 Concerns over pedi- atric zirconia crowns include an inability to manipulate the margin to create an ideal seal, and the need for additional tooth reduction (leading to possible pulpal exposure), while still leaving enough tooth structure for retention. While many options exist for esthetic resto- rations in anterior primary teeth (Figures 6A through 6C, page 9), to date, very little controlled clinical data are available to suggest that one type is superior to the others. Clinical decisions regarding the choice of restoration and the ultimate outcome are dictated by the extent of decay, moisture and hemorrhage control, and the child’s level of cooperation, as well as caries risk, parental desires, and the operator’s experience and clinical preferences.32,33 Many new materials and techniques are avail- able to dentists who treat children. Ultimately, clinicians can ensure the optimal combination of function, long-term performance and es- thetics by selecting the right material for the right situation. Doing so will help set pediatric patients on a lifetime course of improved oral and systemic health. CE Sponsored by VOCO DECISIONS IN DENTISTRY Other considerations include cost and the learn- ing curve in placing zirconia. Currently, there is little information on their long-term clinical performance. Yet these crowns show high pa- rental satisfaction19 more popular.30–32 a six-month follow-up period, zirconia crowns demonstrated a 100% success rate, while 22% of CSCs experienced either fracture or complete loss, and 5% of the PVSSCs lost a portion of the veneer.29 zirconia crowns showed improved health, while the other crowns showed increased gingival inflammation.29 and are likely to become In a prospective study with In evaluations of gingival health, This may possibly be attributed to the highly polished surfaces and biocompat- ibility of zirconia crowns.32 Opposing tooth wear was noted in four out of 38 zirconia crowns studied.29 8
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