Optical properties of zirconia-reinforced lithium silicate veneers obtained with CAD/CAM milling and hot-pressing techniques: a comparative in vitro study.

Background and aims: Dental veneers have become increasingly required among patients, but little is known about the optical properties of veneers obtained from the same ceramic material through different processing techniques. Methods: In this study we compared the translucency and the opalescence parameters of zirconia-reinforced lithium silicate (ZLS) veneers restorations fabricated through CAD/CAM milling and hot-pressing techniques on the upper central incisor. Eighty specimens divided into 8 groups (n=10) were sectioned (Celtra Duo) and heat pressed (Celtra Press) to obtain 0.8 mm thickness. The optical parameters were calculated from the color difference against different backgrounds. Analysis of variance, one way ANOVA and post-hoc multiple comparison tests were used to evaluate and compare the optical properties of the same material, with a significance level of p < 0.05. Results: The processing method had significant effect on optical parameters. Celtra Duo HT proved to be the material with the highest transparency degree. The hot-pressing technique led to higher opacity than CAD/CAM milling technique. Conclusions: For a bio-mimetic aesthetic prosthetic restoration, the ceramic materials must have the same translucency and opacity as the real tooth. The results of this study revealed that high translucency ZLS obtained through hot pressing technique was the material of choice, as it fulfilled these requirements.

Marginal fit of milled versus different 3D-printed materials for provisional fixed dental prostheses: an in vitro comparative study.

Introduction: Provisional dental prostheses are used as interim restorations to help patients perform oral functions between the time of tooth preparation and the placement of the final restoration. A provisional dental prosthesis should protect the abutment from pulpal and gingival aggressions, adapt correctly to keep healthy gingival tissues, be durable, and have a low price. The purpose of this in vitro study was to compare the marginal adaptation of different types of provisional fixed dental prostheses (PFDP), fabricated using 3D printing technology versus the milling (computer-aided manufacturing [CAM]) technique. Method: Two resin teeth (second premolar and second molar) on a typodont were prepared for three-unit provisional fixed dental prostheses. Thirty models were 3D-printed after a digital model was created using an intraoral scanner. Then, 30 provisional fixed dental prostheses (PFDPs) were made from a variety of materials using a digital design of a 3-unit PFDP and STL files delivered to a milling machine and a 3D printer, respectively. Ten PFDP were milled (CAM), and two sets of ten each, were fabricated with 3D printing technology (stereolithography), using two different materials. All restorations were analyzed under a microscope, and marginal gap was then measured using the software Image J. Results: The milled group presented the best marginal gap values (ranging from 86 to 108 µm) and a median value of 93 µm, followed by GC group with (110-251 µm) with a median value of 205 µm and the PR group with median value of 316.5 µm. Conclusion: According to the findings of this in vitro study, the milling (CAM) technique and SLA technology provides acceptable marginal fit values to fabricate provisional fixed partial dentures.

Impact of unilateral removable partial dentures versus removable partial dentures with major connector on oral health-related quality of life of elder patients: a clinical study.

OBJECTIVE: This study aimed to establish the survival rate of unilateral removable partial dentures (u-RPD) comparative with bilateral RPD (bi-RPD) with major connector in elder patients, as well as to determine both their treatment satisfaction and oral health. METHODS: The study sample included 17 patients treated with u-RPD and 17 patients treated with bi-RPD with a major connector. The patients were followed over five years with recalls every 6 months. A 5- points Likert scale was used to determine the satisfaction of the patients. The Oral Health Impact Profile-14 (OHIP-14) questionnaire was used to evaluate their oral health after each type of administrated treatment. The local oral examined aspects included the maintenance of the abutment teeth periodontal health, the fractures of the removable dentures, the fractures of the connectors, the chipping of the aesthetic material. Kaplan-Meier survival analysis was conducted to evaluate the performance of the two treatments. RESULTS: The mean survival time in years was 4.882 ± 0.114, 95% CI (4.659; 5.106) and 4.882 ± 0.078, 95% CI (4.729; 5.036), for the u-RPD and the bi-RPD, respectively. The five-year survival rates for the two dentures were 94.1% for u-RPD vs. 88.2% for bi-RPD with a major connector, without a statistically significant difference between them (Log-rank test χ2(1) = 0.301, p = 0.584). The patients receiving u-RPD presented significantly higher satisfaction scores compared to the patients receiving bi-RPD, 4.88 ± 0.48 vs. 4.41 ± 0.62, Mann-Whitney U test, p = 0.026. CONCLUSION: Patients receiving u-RPD presented higher levels of treatment satisfaction and better oral health than patients receiving bi-RPD. The survival rates of the treatments u-RPD and bi-RPD were similar.

Efficacy of PerioTabs, a NitrAdine-based gingiva brushing solution, on periodontally affected patients treated with fixed partial dentures: a randomized controlled study.

Objectives: Recent data show that teeth prepared with horizontal finishing lines supporting crowns and fixed partial dentures present more periodontal disorders than untreated control teeth. Several studies have shown that NitrAdine (bonyf) induces a significant reduction of dental biofilm. The aim of this study was to demonstrate that 10-day use of PerioTabs (bonyf), a NitrAdine-based gingiva brushing solution, is effective in treating gingival inflammation of prosthodontic patients. Method and materials: Forty-nine subjects were instructed to brush their teeth, gingivae, and prostheses with the PerioTabs solution for 10 days (treatment group) and 49 with any toothpaste (control group). The initial and 11-day Plaque Index and Bleeding Index were recorded. A five-point Likert scale was used to evaluate the level of patient satisfaction. The Shapiro-Wilk statistical test was used to compare the results for the two groups. Results: Highly significant differences between the treatment and control group (P < .001) for the Plaque Index and Bleeding Index resulted. The treatment group patients' satisfaction was high: 31 (63.3%) reported the highest level, 5, on the Likert scale, and 18 (36.7%) declared they were satisfied (level 4). Conclusions: The use of a NitrAdine-based gingiva brushing solution (PerioTabs) was effective in reducing the gingival inflammation in periodontally affected patients treated with fixed partial dentures. Clinical relevance: The NitrAdine-based gingiva brushing solution (PerioTabs) was highly accepted by the patients and seems to be a promising alternative to the solutions widely used.

Trueness and Precision of Two Intraoral Scanners: A Comparative In Vitro Study.

The aim of this study was to evaluate the accuracy of two intraoral scanners used in the dental office. A molar fixed in a typodont was prepared for a ceramic onlay. The preparation was scanned using a high-resolution scanner (reference scanner) and saved as stereolithography (STL) format. The prepared resin molar was scanned again using the intraoral scanners, and all the scans were saved as well in STL format. All STL files were compared using metrology software (Geomagic Control X). Overlapping the meshes allowed the assessment of the scans in terms of trueness and precision. Based on the results of this study, the differences of trueness and precision between the intraoral scanners were minimal.