How Efficient Are Clear Aligners? Clear Aligners vs Traditional Orthodontic Treatment: A Systematic Review

Purpose:The purpose of the present review is to update knowledge of the literature and better understand the efficiency and abilities of clear aligners and to clarify their indications for use.Materials and Method:The study question was defined as ‘‘How efficient is orthodontic treatment with clear aligners in comparison to fixed orthodontic treatment in patients with permanent dentition?’’ An Internet-based search was performed with 6 databases: Medline, PubMed, Clinical Key, ProQuest Dissertations and Theses, Dentistry and Oral Sciences Source (EBSCO Host), and the Cochrane Library. The final search was run in January 2014. Key words used were clear aligner, eCligner, Invisalign, and AsoAligner.Results:We retrieved 110 publications from the databases. After reviewing titles and abstracts, case reports and clinical studies reporting treatment outcomes on segmental dental arches (i.e., anterior dentition) were excluded. Finally, 3 studies that addressed the study question were included in the review.Conclusion:Not enough studies were available to arrive at definite conclusions to compare clear aligner and fixed orthodontic treatment. In simpler cases, Invisalign may result in treatment outcomes as good as those of traditional orthodontic treatment. However, controlled clinical studies are necessary to define and support the abilities and limits of clear aligner therapy with evidence

Does the Bone Cement Affect Miniscrew Stability?

Objective:The purpose of this study was to determine whether bone cement increased the resistance of miniscrews against pull-out and shear forces.Materials and Method:Sixty commercially available miniscrews were placed into bovine bone samples (one each) at a 90° angle, using a custom-made orientation jig and controlling torque (30 N-cm) and rotation (20 rpm) with a rechargeable screwdriver. The miniscrews were inserted using three different methods: self-drilling, predrilling, and predrilling with bone cement application. Pull-out strengths and shear tests were performed using a universal testing machine.Results:Nonparametric Kruskal-Wallis tests were used for comparisons between groups, and Bonferroni-adjusted Mann-Whitney U tests were used to detect different group(s) (α/3=0.016). There was a statistically significant difference between the pull-out strengths of the groups (p<0.01). The self-drilling group had a significantly lower pull-out strength at failure than the other groups (p<0.016). The pullout strengths of the miniscrews placed with bone cement had a significantly higher pull-out strength than the predrilling group. In shear tests, there was no statistically significant difference among the groups.Conclusion:This study is the first report demonstrating the effects of bone cement on stability and resistance to failure at the bone-miniscrew interface. These results show that the use of miniscrews with bone cement is a promising method that may extend the limits of force application