ABSTRACT
Key Clinical Message: Veneer crowns can be used in anterior endodontically-treated teeth with light occlusal force and enamel substrate consideration as a more conservative approach instead of conventional all ceramic crowns. Abstract: All-ceramic anterior crowns and veneers have been used widely in dentistry with high clinical success rate. The development of new reinforced ceramics in recent years has led to more use of extended defect-oriented preparation designs, that is, extended veneers, instead of full crown preparations which are less invasive. A veneer crown is simply a veneer that covers the entire tooth. The preparation preserves remaining enamel and uses a conservative preparation design. Its indication should be carefully raised taking into consideration various factors. The preparation design is crucial to ensure longevity of such restoration. The balance is between sufficient preparation for the material thickness and adequate strength against occlusal load and the enamel preservation. A 24-year-old man referred to the restorative department of the Dentistry School of Tehran University of Medical Sciences complaining from his poor esthetics in the maxillary incisors. In clinical and radiographic evaluation, he had open bite, composite discoloration due to corrosion of the pre-fabricated posts in all four incisors, a periapical lesion in tooth 21 and under-filled root canal therapy in tooth 22. All four posts and composite restorations were removed and teeth 21 and 22 were retreated. Although the amount of remaining tooth tissue was low, it had enough enamel thickness, especially in the buccal area. Taking into consideration this mixed enamel and dentin substrate, endodontics access, esthetics needs and canine guidance occlusion with no parafunction history, bonded lithium disilicate veneer crowns were selected to restore the maxillary incisors. A 12-month follow-up showed promising clinical (healthy gingival tissue and successful restorations) and radiographic (reduced periapical lesion) outcomes.
ABSTRACT
Aim: The present study investigated the effects of laser and conventional in-office bleaching, and polishing on the color of stained composite resin. Materials and Methods: A microhybrid composite (Clearfil AP-X) and a nanohybrid composite (Grandio) were selected. Twenty-four discs (2 × 10 mm) for each composite were prepared. The samples were immersed in coffee solution (25 g of coffee in 250 mL water) for seven days. Then the samples were divided into three groups (n = 8) and the stains were removed using bleaching (with Opalescence Xtra Boost), diode laser irradiation with Heydent material and a Sof-Lex polishing kit. The L ∗a ∗b ∗ color parameters were determined using a spectrophotometer before and after immersion and after stain removal procedures, and the overall color changes (ΔE) were calculated. The data were analyzed with two-way analysis of variance. Results: In the Clearfil composite resin group, the mean ΔE compared to the baseline using in-office bleaching, laser irradiation, and Sof-Lex polishing kit were 3.31, 3.35, and 4.93, respectively. These values with the Grandio composite resin were 3.31, 6.35, and 4.57, respectively. The highest capacity to remove stains was related to the conventional in-office bleaching method. Grandio composite resin underwent more color changes than Clearfil composite resin significantly (P-value < 0.05). Conclusion: Both composite resins exhibited color changes after immersion in the discoloring solution. However, after staining-removing procedures, the ΔE values decreased. Decreases in the ΔE values were not sufficient to restore the color to that before immersion in the discoloring solution with any stain-removing methods.
ABSTRACT
Introduction: Bleach-shade composite resins were recently introduced to the market due to the high demand of patients for whiter teeth. This study sought to compare four stain removal methods for bleach-shade composite resins. Materials and Methods: Seventy-two discs were fabricated from each of the Filtek Z350 XT and Gradia XBW composite resins and immersed in coffee or sour cherry juice staining solutions. Each group was then divided into four subgroups to assess the efficacy of four stain removal methods (finishing with soft-lex disk "brush with pumice" bleaching with carbamide peroxide 16%, bleaching with hydrogen peroxide 40%). The color of each specimen was measured by Easyshade spectrophotometer, and data were analyzed using SPSS 25 statistical package for social sciences. Results: The home-bleaching technique was more effective than the office-bleaching and pumice for the removal of sour cherry juice stain (ΔE = 1.93) and coffee stain (ΔE = 3.32) from Gradia composite discs, almost returning the baseline original color. The Sof-Lex discs were more effective than the pumice for the removal of sour cherry juice stain (ΔE = 4.11) and coffee stain (ΔE = 4.93) from Z350 composite discs but not return the baseline original color. Conclusions: Filtek Z350 had more discoloration than Gradia Direct. The different materials and solutions reacted differently to the four stain removal methods. In GCJ group after all stain removal methods, ΔE reduced to a clinically acceptable level.
ABSTRACT
Purpose: This study aimed to assess the color stability of resin cements subjected to xenon radiation and evaluate their color change (ΔE) during time. Materials and Methods: In this in vitro experimental study, 15 specimens (8 mm in diameter and 2 mm in height) were made from a light-cured resin cement (Choice 2, Bisco, USA) and two dual-cured resin cements (Panavia F2 and V5, Kuraray Co, Ltd, Osaka, Japan). For assessment of color change, ΔE parameters were measured immediately (ΔE1) and 24 h (ΔE2) after polymerization using XRiteCi64 spectrophotometer. Next, they were subjected to xenon lamp radiation (122 h at 35C° and 22% humidity in off mode and 95% in light mode). Then, their color change was measured again (ΔE3). The mean ΔE and standard deviation of all specimens were calculated, and data analysis was done using analysis of variance and Tukey's honestly significant difference. Results: L* values had a tendency to decrease and Panavia F2 and Choice 2 had the highest change after accelerated aging. The comparison of Δa and Δb showed no significant difference between cements except Δa in Panavia F2. All the values were clinically acceptable (ΔE >3.3). The lowest Δ E1 was for Panavia V5 and the highest Δ E1 was measured for Panavia F2. After accelerated aging, there was no significant difference between Panavia V5 and choice 2 (P > 0/05). Conclusions: Following polymerization and under xenon radiation, ΔE of all the specimens was clinically acceptable.
