Color stability of precolored and extrinsically colored monolithic multilayered polychromatic zirconia: Effects of surface finishing and aging.

PURPOSE: To explore the impact of zirconia types, coloring methods, and surface finishing on the color stability of monolithic multilayered polychromatic zirconia after artificial aging, including thermocycling and simulated toothbrushing. MATERIALS AND METHODS: Eighty square-shaped zirconia samples were divided into 2 types (M3Y-TZP and M6Y-PSZ), further categorized based on coloring methods (precolored and extrinsically colored) and surface finishing techniques (mechanical polishing or glazing). The color stability was assessed using the CIEDE2000 formula. Artificial aging was simulated via thermocycling and toothbrushing. All samples were analyzed with a spectrophotometer to determine the post-aging color changes (ΔE00). The ΔE00 were interpreted and classified using the 50:50% perceptibility threshold (PT) and the 50:50% acceptability threshold (AT). Comparisons between groups for ΔE00 differences were performed using three-way ANOVA, with pairwise comparisons facilitated by Fisher's protected least significant difference test, α = 0.05. RESULTS: The study results indicated significant impacts of zirconia type, coloring method, and surface finishing on color stability. The M6Y groups experienced significantly greater color changes (6.61 ± 1.63) compared to the M3Y groups (3.40 ± 2.24), p < 0.0001. For both types of zirconia, extrinsically colored samples exhibited significantly higher ΔE00 when mechanically polished (p = 0.004). However, surface finishing had no significant effect on ΔE00 in precolored samples of either zirconia material (p = 1.000). The evaluation and categorization of ΔE00 variations indicated that nearly all color changes in the M6Y groups, regardless of being precolored, extrinsically colored, polished, or glazed, were deemed extremely unacceptable (Grade 1). In contrast, the M3Y groups showed more acceptable results, with the majority of color changes classified as moderately unacceptable (Grade 3). CONCLUSIONS: The color stability of multilayered polychromatic zirconia is influenced by the type of material, extrinsic coloring, and the chosen surface treatment post-artificial aging. The translucent 6Y-PSZ exhibited lower color stability, especially with only mechanical polishing. For the fabrication of M3Y-TZP and 6Y-PSZ monolithic multilayered polychromatic zirconia restorations, extrinsic coloring should be paired with glazing to maintain color stability. Conversely, in the absence of extrinsic coloring, both glazing and mechanical polishing are effective in preserving color stability.

Digital workflow for duplication of gold onlay anatomy to monolithic zirconia onlay for a complete denture: A technique paper.

Digital replication of an existing cast gold onlay anatomy to a more esthetic material for a new complete denture is challenging. A technique is presented that uses digital technology to fabricate a new maxillary complete denture with monolithic zirconia onlays that duplicate the anatomy of an existing complete denture with cast gold onlays.

Digital beading for a CAD-CAM framework for an implant-supported overdenture: A dental technique.

The analog technique of making bead lines for a metal superstructure framework for the maxillary implant-supported overdenture is created by scribing shallow grooves on the surface of a definitive gypsum cast. This report describes a digital technique that uses computer-aided design and computer-aided manufacturing technology to make dental bead lines on an intraoral impression without using the gypsum cast.

Use of a CAD-CAM Surgical Template to Improve Accuracy for Simultaneous Implant Removal, New Implant Placement, and Bone Graft.

A fractured implant is considered a catastrophic failure that leads to the loss of the implant and the prosthesis. Available methods of implant removal include the reverse screw technique, use of trephines, or osteotomies around the implant. In case of a fractured implant, the access hole for the reverse screw technique is impossible, leading to the need for an osteotomy. When the apical part of the fractured implant is embedded in bone, finding the piece may lead to a more ample osteotomy and significant bone loss, complicating future implant placement. This technique presented utilized a CAD-CAM surgical template that was designed with the purpose of improving accuracy in finding the fractured part with minimal osteotomy, allowing for simultaneous placement of a new implant in the same site, with additional bone graft, utilizing the same template.

Efficacy of a Self-Designed Mobile Application to Improve Child Dental Health Knowledge among Parents.

OBJECTIVES: The objective of the study is to develop a mobile-based application and assess its efficacy in improving child dental health knowledge of parents. SUBJECTS AND METHODS: A mobile-based application (Your child's smile) was developed and made available on application-store and play store. This application provided all essential information to parents on child dental health prepartum and from infancy to adolescence. To assess improvement in parent's knowledge two similar pretested questionnaires were incorporated within the application, one to be filled at initial registration and other after the parents had utilized the application. Responses were entered into MS excel sheet and analyzed using IBM SPSS statistics version 20.0. RESULTS: Within the 15 days' research period, the application was downloaded by 230 parents out of whom 110 answered only the 1st and 120 both questionnaires. Out of the 120 who responded to both majority showed highly significant (P < 0.01) or significant (P < 0.05) improvement in their knowledge on tooth development, importance of deciduous teeth, importance of regular dental check-up, pit and fissure sealants, bedtime bottle use, and consequence of early loss of deciduous teeth. Confidence in child dental health knowledge was also evident in other areas with more parents opting for agreeing, strongly agree, or disagree options. A majority 75% of parents favored the use of mobile applications as an effective child dental health knowledge tool. CONCLUSION: Within the limitations of the study, we can conclude that mobile based applications are an effective tool for providing child oral health knowledge to parents and significant improvement in knowledge is evident after parents utilized the mobile-based application.