ABSTRACT
BACKGROUND: Zirconia crowns, resembling crystals and with enamel-like aesthetics, are recent entrants in pediatric restorative dentistry. Despite growing use, their empirical efficacy remains under-explored. The aim of this study is to compare resin composite strip crowns and premanufactured zirconia crowns on primary maxillary incisors. METHODS: In the Pediatric Dental Clinics, 240 primary maxillary incisors (69 patients) were treated with either zirconia (120 teeth) or composite strip crowns (120 teeth). Evaluations of gingival health, plaque, secondary caries, restoration failure, and opposing teeth wear occurred at 3, 6, and 12-month intervals. RESULTS: At 3 months, zirconia crowns showed less gum bleeding (P=0.006) and plaque. Through 6 and 12 months, zirconia crowns exhibited fewer failures but higher opposing teeth wear. Strip crowns indicated greater tooth material loss. CONCLUSIONS: Zirconia crowns demonstrated superior gingival health and durability over composite resin strip crowns but caused increased wear on opposing teeth.
ABSTRACT
BACKGROUND: The purpose of this study evaluates and compares the effect of surface roughness (Ra) and color stability on computer-aided design/computer-aided manufacturing (CAD/CAM) hybrid resin (Vita Enamic), feldspathic (Vitablocs® Mark II), and lithium disilicate Zirconia (Vita Suprinity) glazed or polished ceramics immersed in hot Arabic Qahwa and cold coffee. METHODS: A total of 96 standardized samples were prepared from CAD/CAM restorative materials. Half of the samples were polished as per the manufacturer's instructions using a porcelain polishing kit, and the other half were glazed. Samples were distributed and immersed in hot Arabian Qahwa and cold coffee followed by thermocycling. Ra measurements and color changes were conducted before and after immersion. SEM images were captured from each type of glazed or polished ceramic. One-way ANOVA paired Student's t-test, and Bonferroni test were conducted to detect significant difference between the groups. P > 0.05 was a significant level. RESULTS: Of all the tested samples, Ra increased without any significant difference; however, mean color changes (ΔE*) showed significant differences. An increase in Ra was noted for all the glazed and polished samples after immersion and thermocycling. However, differences were significant only in VM II. In addition, ΔE* was significant only in Vita Suprinity (VS) samples. For immersion groups, significant Ra changes were noticed in glazed samples, only in Vita Enamic (VE) with no ΔE*. In polished samples, mean Ra changes were observed in VM II and VS samples. Significant differences were also noticed in polished VE and VS subgroups of ΔE*. CONCLUSIONS: Ra affects all the tested samples, providing higher values on the polished specimens. The ΔE* caused by hot Arabic Qahwa and cold coffee on glazed or polished CAD/CAM restorative materials were clinically acceptable.
Subject(s)
Coffee , Immersion , Ceramics , Color , Computer-Aided Design , Humans , Materials Testing , Surface Properties , ZirconiumABSTRACT
Background and Objectives: Khat chewing is considered as a daily habit that is practiced by more than five million people globally. The effect of khat chewing on the surface roughness and the color stability of natural teeth and the material used in the fabrication of dental prosthesis remains unknown. This study was conducted to explore and compare the effect of khat homogenate (KH) on the surface roughness (Ra) and the average color changes (ΔE*) amongst natural teeth and selected shades from different porcelain types, namely, feldspathic metal ceramic (MC) VM13, computer-aided design/computer assisted manufacture (CAD/CAM) feldspathic (Vitablocs Mark II), and multilayer zirconia (Ceramill Zolid PS) porcelains. Materials and Methods: Seventy samples were prepared from natural teeth, feldspathic MC, CAD/CAM Vitablocs Mark II, and zirconia porcelain. The Ra values were measured using a profilometer and expressed in micrometers, whereas the ΔE* values were measured using VITA Easyshade® V spectrophotometer for all samples before and after frequent immersion and thermocycling in KH for 30 days. The surface topography was used to assess the materials surfaces (glazed or polished) after KH immersion by using a white light interferometry machine. Results: Results revealed that the Ra and the ΔE* values of the different types of tested porcelain were influenced by KH. The order of surface roughness values was glazed or polished MC > polished Zircon > polished Vitablocs Mark II > natural teeth. The lowest ΔE* values were recorded for glazed Vitablocs Mark II and MC, and the values could be arranged as polished zircon > natural teeth > glazed zircon > polished MC > polished Vitablocs Mark II. P values were significantly varied (< 0.001) among all the tested groups, except the zircon group (>0.05) for both Ra and ΔE*. Conclusion: KH significantly affected both surface parameter and color of glazed or polished porcelain materials and natural teeth.