Research Spotlight

Alam, A. (2021). “Effect of Near Monopoly in the Left Ventricular Assist Device Market.” Am J Cardiol Oct 24;S0002-9149(21)00957-7. [Epub ahead of print].

Full text of this article.

These 2 devices were the most implanted LVADs in the world. However, on June 3, 2021, Medtronic announced that it would stop distribution of the HVAD, given the malfunctioning of the device’s start and stop mechanisms in addition to a high frequency of neurologic events. With HVADs no longer being implanted, will HM3 now monopolize the LVAD market? Herein a brief overview of LVADs that are within the horizon of our time.[No abstract; excerpt from article].

Zandinejad, A., M. Revilla-León, M. M. Methani, L. Nasiry Khanlar and D. Morton (2021). “The Fracture Resistance of Additively Manufactured Monolithic Zirconia vs. Bi-Layered Alumina Toughened Zirconia Crowns When Cemented to Zirconia Abutments. Evaluating the Potential of 3D Printing of Ceramic Crowns: An In Vitro Study.” Dent J (Basel) 9(10).

Full text of this article.

(1) Background: This study compared the fracture resistance of additively manufactured monolithic zirconia and bi-layered alumina toughened zirconia crowns on implants. (2) Methods: Maxillary model with a dental implant replacing right second bicuspid was obtained. Custom abutments and full-contour crowns for additively manufactured monolithic zirconia and bi-layered alumina reinforced zirconia crowns (n = 10) were fabricated. The crowns were cemented to implant-supported zirconia abutments and the assembly fixed onto resin blocks. Fracture resistance was measured using a universal testing machine at a crosshead speed of 2 mm/min. A Kruskal-Wallis test was used to analyze the data. (3) Results: Although additively manufactured monolithic zirconia crowns demonstrated a higher mean fracture resistance than bi-layered alumina toughened zirconia crowns, statistical analysis revealed no significant difference in fracture resistance between the two groups. All specimens fractured at the implant-abutment interface. (4) Conclusions: Additively manufactured bi-layered alumina toughened zirconia crowns demonstrated similar fracture resistance to additively manufactured monolithic zirconia crowns when cemented to implant-supported zirconia abutments.

Serra-Pastor, B., N. Bustamante-Hernández, A. Fons-Font, M. F. Solá-Ruíz, M. Revilla-León and R. Agustín-Panadero (2021). “Periodontal outcomes of anterior fixed partial dentures on teeth treated with the biologically oriented preparation technique: A 6-year prospective clinical trial.” J Prosthet Dent.

Full text of this article.

STATEMENT OF PROBLEM: One of the most frequent complications in participants with fixed partial dentures (FPDs) is the apical migration of the gingival margin, which may be associated with factors such as fit, gingival margin location, or tooth preparation type. The prevalence of the complication in participants restored with FPDs prepared by using the biologically oriented preparation technique (BOPT) is unclear. PURPOSE: The purpose of this prospective clinical trial was to evaluate the clinical and biologic outcomes of FPDs on teeth prepared by using the BOPT, over a 6-year follow-up period. MATERIAL AND METHODS: Tooth-supported zirconia FPDs in the anterior region prepared by using the BOPT were evaluated. Each participant was monitored annually for 6 years by evaluating plaque index, probing depth, vestibular gingival thickness, and gingival margin stability. Biologic and/or mechanical complications were also recorded. Patient satisfaction was measured by using a visual analog scale (VAS). RESULTS: A total of 25 FPDs supported by 70 teeth in 24 participants were analyzed. Low plaque index values and stable probing depths were observed, whereas the gingival index was 0 for most of the teeth. Teeth treated by using the BOPT presented significant increase in gingival thickness, and the gingival margin was found to be stable in 100% of the treatments. FPD survival was 100%. CONCLUSION: Tooth supporting FPDs prepared by using the BOPT presented good periodontal health and gingival margin stability, without recession and with a 100% survival rate during a 6-year follow-up.

Revilla-León, M., N. Quesada-Olmo, M. Gómez-Polo, E. Sicilia, M. Farjas-Abadia and J. C. Kois (2021). “Influence of rescanning mesh holes on the accuracy of an intraoral scanner: An in vivo study.” J Dent: 103851. [Epub ahead of print].

Full text of this article.

OBJECTIVES: To evaluate whether the cutting-off and rescanning procedures have an impact on the accuracy (trueness and precision) of the intraoral digital scan. METHODS: A right quadrant digital scan (reference scan) of a participant was obtained using an intraoral scanner (IOS) (TRIOS 4; 3Shape A/S, Copenhagen, Denmark). The reference scan was duplicated 135 times and divided into 3 groups based on the number of rescanned mesh areas: 1 (G1 group), 2 (G2 group), and 3 (G3 group) mesh holes. Each group was subdivided into 3 subgroups depending on the mesh hole diameter: 2 mm- (G1-2, G2-2, and G3-2), 4 mm- (G1-4, G2-4, and G3-4), and 6 mm- (G1-6, G2-6, and G3-6) (n = 15). A software program (Geomagic; 3D Systems, Rock Hill, SC, USA) was used to assess the discrepancy between the reference and the experimental scans using the root mean square (RMS). Kruskal-Wallis and post hoc multiple comparison Dunn’s tests were used to analyze the data (α=0.05). RESULTS: Trueness ranged from 5 to 20 µm and precision ranged from 2 to 10 µm. For trueness assessment, Kruskal-Wallis test revealed significant differences on the RMS error values among the groups tested (P<.05). The G3-6 group obtained the lowest trueness and lowest precision values, while the G1-2, G1-4, G2-2, G2-4, and G3-2 groups computed the highest trueness and precision values. When comparing groups with the same number of rescanned mesh holes but with different diameter, the higher the diameter of the rescanned mesh hole, the lower the trueness values computed; however, when comparing groups with the same diameter of the rescanned mesh hole but with differing number of rescanned mesh holes, no significant differences were found in the RMS values among the groups. For the precision evaluation, Levene's test showed a lack of equality of the variances, and therefore of the standard deviations. The F-test with Bonferroni correction identified significant differences between the SDs between group G3-6 and all the other groups. When comparing instead the interquartile range (IQRs) due to the non-normality of the data, groups G1 and G2 also showed lower IQR values or higher precision than groups G3. CONCLUSIONS: Cutting-off and rescanning procedures decreased the accuracy of the IOS tested. The higher the number and diameter of the rescanned areas, the lower the accuracy. CLINICAL SIGNIFICANCE: Cutting-off and rescanning procedures should be minimized in order to increase the accuracy of the IOS evaluated. The intended clinical use of the intraoral digital scan is a critical factor that might determine the scanning workflow procedures.

Shulman, J. D. and N. S. Makrides (2021). “Civil Rights Litigation Involving the Dental Care of Incarcerated Persons.” J Correct Health Care.

Full text of this article.

Individuals incarcerated in jails, prisons, and detention centers are unique because they have an entitlement to health care under the U.S. constitution; however, the dental care they receive is highly variable in scope and quality. We identified federal civil rights lawsuits related to dental care by incarcerated individuals that were decided in federal district courts in 2018 and courts of appeals since 1976. Judges dismissed or denied the majority of dental claims. Courts have little guidance to inform decisions relating to dental care because cases rarely have a dental expert and the dental profession has not set forth recommendations about the scope of correctional dental care. In the absence of guidance from the dental profession, oral health policy decisions have been left to the discretion of the courts and correctional administrators (nondentists), yielding inconsistent and often detrimental results.