Esthetic integration area concept in digitally guided veneer rehabilitation: A dental technique.

Computer-aided design and computer-aided manufacturing (CAD-CAM) technologies have been integrated into the dental digital workflow. However, pretreatment virtual veneer preparations and the digital design and manufacturing of guided preparation and cementation templates has not yet been incorporated into the clinical routine. This article presents a novel protocol for digitally guided veneer rehabilitation by following the esthetic integration area concept, facilitating precise control over tooth structure removal and obviating the need for interim restorations.

Influence of base designs on the manufacturing accuracy of vat-polymerized diagnostic casts using two different technologies.

STATEMENT OF PROBLEM: Diagnostic casts can incorporate different base designs and be manufactured using different vat-polymerization technologies. However, the influence of the interrelation between the base design and the 3D printing technology on the casts' final accuracy remains unclear. PURPOSE: The purpose of this in vitro study was to assess the influence of different base designs of 3D printed casts on the accuracy of 2 vat-polymerization technologies. MATERIAL AND METHODS: A digital maxillary cast was obtained and used to generate 3 different base designs: solid (S group), honeycombed (HC group), and hollow (H group). The HC and H groups were subdivided based on the wall thickness of the cast design, resulting in 2 subgroups with thicknesses of 1 mm (HC1 and H1) and 2 mm (HC2 and H2) (N=100, n=10). Eleven reference cubes were added to each specimen for subsequent measurements. Specimens were manufactured by using 2 vat-polymerization 3D printers: Nextdent 5100 (ND group) and Sonic Mini 4K (SM4K group) and a resin material suitable for both 3D printers (Nextdent Model 2.0). A coordinate measuring machine quantified the linear and 3-dimensional discrepancies between the digital cast and each reference specimen. Trueness was defined as the average absolute dimensional discrepancy between the virtual cast and the specimens produced through additive manufacturing (AM), while precision was delineated as the standard deviation in dimensional discrepancies between the digital cast and the AM specimens. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U pairwise comparison tests (α=.05). RESULTS: For the NextDent group the trueness ranged from 21.83 µm to 28.35 µm, and the precision ranged from 17.82 µm to 37.70 µm. For the Phrozen group, the trueness ranged from 45.15 µm to 64.51 µm, and the precision ranged from 33.51 µm to 48.92 µm. The Kruskal-Wallis test showed significant differences on the x-, y-, and z-axes and in the 3D discrepancy (all P<.001). On the x-axis, the Mann-Whitney U test showed significant differences for the Phrozen group between the H-2 and H-1 groups (P=.001), H-2 and S groups (P<.001), and HC-2 and S groups (P=.012). On the y-axis, significant differences were found in the Phrozen group between the H-2 and H-1 groups (P=.001), the H-2 and S, H-1 and HC-1, and HC-1 and S groups (P<.001), the H-1 and HC-2 groups (P=.007), and the HC-2 and S groups (P=.009). The NextDent group exhibited significant differences, particularly among the HC-1 and H-2 groups (P=.004), H-1 (P=.020), and HC-2 (P=.001) groups; and on the z-axis significant differences were found in the Phrozen group between the H-2 and H-1 and S groups and the HC-2 group and H-1 and S groups (both P<.001). In the NextDent group, significant differences were found between the H-2 and HC-2 (P=.047) and HC-1 (P=.028) groups. For the 3D discrepancy analysis, significant differences were found in the Phrozen group between the H-2 and H-1 and S groups (P<.001), the H-1 and HC-2 groups (P=.001), the S and HC-1 and HC-2 groups (P<.001), and the H-1 and HC-1 groups (P=.002). In the NextDent group, significant differences were observed between the H-2 and HC-1 groups (P=.012). CONCLUSIONS: The accuracy of digital casts depends on the manufacturing trinomial and base design of the casts. The honeycomb and hollow based designs provided the highest accuracy in the NextDent and Phrozen groups respectively for the material polymer tested. All specimens fell in the clinically acceptable range.

Comparative Clinical Study of Two Tooth Whitening Protocols. A Randomized Clinical Trial. Part 2.

This study aimed to clinically evaluate the efficacy of two different home whitening protocols and to determine which is more effective: applying the whitening gel every 48 hours or every 72 hours for 6 weeks. The differences in terms of tooth sensitivity are also analyzed. A sample of 72 patients was randomly divided into 3 groups of 24 (N=24). Group A: 16% carbamide peroxide applied every 48h for 6 weeks. Group B: 16% carbamide peroxide applied every 72h for 6 weeks. Group C (control group): a placebo gel without peroxide (glycerin gel) was applied every 48h for 6 weeks. To compare the groups, color measurements were made using a spectrophotometer and ANOVA test and Bonferroni test was used. The confidence level was set at 95% (p ≤ 0.05) and no statistically significant differences between applying 16% carbamide peroxide every 48h or every 72h for 6 weeks (p> 0.05) were found. The study concluded that carbamide peroxide 16% is equally effective applied with both protocols, obtaining the same results.

Comparative Clinical Study of Two Tooth Whitening Protocols.

This study aimed to clinically evaluate the effectiveness of two different at-home whitening protocols and to determine which is more effective: applying the whitening gel (16% carbamide peroxide) every 24 hours (Group A) or every 48 hours (Group B) for 2 weeks. Group C received a placebo gel (glycerin) without peroxide, which was applied every 24 hours for 2 weeks. The differences in terms of tooth sensitivity were also analyzed. A sample of 60 patients was divided into three groups of 20 patients. To compare the groups, color measurements were made using a spectrophotometer, and Student t test was used for independent samples. The confidence level was set at 95% (P ≤ .05). No statistically significant differences were found between Groups A and B (P > .05). The study concluded that 16% carbamide peroxide was equally effective when applied with either protocol and obtained the same results, but the 48-hour application protocol produced less sensitivity than the 24-hour application protocol.

Esthetic Integration Area concept to improve the emergence profile of fixed restorations: A dental technique.

A technique for obtaining the esthetic integration and optimal emergence profile of tooth-supported and implant-supported restorations is described. Using a computer-aided design software program, data captured with an intraoral scanner were used to establish the anatomic landmarks for determining the maximum buccal volume to which a restoration can be extended. This technique could be applicable to different types of fixed-dental prostheses treatments. Advantages of this technique include the establishment of periodontal-prosthetic criteria and the improvement of clinical and laboratory communication since the same guidelines for evaluating restorative space in the buccolingual direction of tooth preparations are used to avoid overcontoured restorations.