METHODS: Sixteen New Zealand white rabbits, 20 to 24 weeks old, were randomly divided into 4 experimental groups. Modified hyrax expanders were placed across their interfrontal sutures and secured with miniscrew implants located bilaterally in the frontal bone. The hyrax appliances were activated as follows: group 1 (control), 0.5-mm per day expansion for 12 days; group 2, 1-mm instant expansion followed by 0.5 mm per day for 10 days; group 3, 2.5-mm instant expansion followed by 0.5 mm per day for 7 days, and group 4, 4-mm instant expansion followed by 0.5 mm per day for 4 days. After 6 weeks of retention, sutural separation and sutural bone modeling were assessed by microcomputed tomography and quantified. Statistical analysis was performed using Kruskal Wallis and Mann-Whitney U tests and the Spearman rho correlation (P <0.05).
RESULTS: Median amounts of sutural separation ranged from 2.84 to 4.41 mm for groups 1 and 4, respectively. Median bone volume fraction ranged from 59.96% to 69.15% for groups 4 and 3, respectively. A significant correlation (r = 0.970; P <0.01) was observed between the amounts of instant expansion and sutural separation.
CONCLUSIONS: Pending histologic verifications, our findings suggest that the protocol involving 2.5 mm of instant expansion followed by 0.5 mm per day for 7 days is optimal for accelerated sutural expansion. When 4 mm of instant expansion was used, the sutural bone volume fraction was decreased.
Study design: The research was designed as a crossover, randomized control trial.
Materials and methods: Subjects comprised patients receiving fixed appliances at a teaching institution and indicated for VFRs. Post-treatment stone models were scanned with a structured-light scanner. A fused deposition modelling machine was used to construct acrylonitrile-butadiene-styrene (ABS)-based replicas from the 3D scanned images. VFRs were fabricated on the original stone and printed models. Analysis comprised independent t-tests and repeated measures analysis of variance.
Randomization: Subjects were allocated to two groups using Latin squares methods and simple randomization. A week after debond, subjects received either VFR-CV first (group A) or VFR-3D first (group B) for 3 months, then the interventions were crossed over for another 3 months.
Blinding: In this single-blinded study, subjects were assigned a blinding code for data entry; data were analysed by a third party.
Outcome measures: The primary outcome measured was oral health-related quality of life (OHRQoL) based on Oral Health Impact Profile-14 (OHIP-14). Secondary outcome was post-treatment stability measured using Little's Irregularity Index (LII).
Results: A total of 30 subjects (15 in each group) were recruited but 3 dropped out. Analysis included 13 subjects from group A and 14 subjects from group B. Group A showed an increase in LII (P < 0.05) after wearing VFR-CV and VFR-3D, whereas group B had no significant increase in LII after wearing both VFRs. Both groups reported significant improvement in OHRQoL after the first intervention but no significant differences after the second intervention. LII changes and OHIP-14 scores at T2 and T3 between groups, and overall between the retainers were not significantly different. No harm was reported during the study.
Conclusion: VFRs made on ABS-based 3D printed models showed no differences in terms of patients' OHRQoL and stability compared with conventionally made retainers.
Registration: NCT02866617 (ClinicalTrials.gov).
METHODS: An interventional, pre-post non-clinical randomised controlled study was conducted among randomly distributed 162 [control (n = 54), test 1 (n = 54) and test 2 (n = 54) groups] newly diagnosed diabetics by a consecutive sampling method for 18 months. Direct healthcare costs (direct medical and non-medical costs) from patients perspective was estimated by 'bottom up' approach to identify their out-of-pocket expenses (1USD = NPR 73.38) before and after intervention at the baseline, 3, 6, 9 and 12 months follow-ups. Test groups' patients were nourished with pharmaceutical care intervention while control group patients only received care from physician/nurses. Non-parametric tests i.e. Friedman test, Mann-Whitney U test and Wilcoxon signed rank test were used to find the differences in direct healthcare costs among the groups before and after the intervention (p ≤ 0.05).
RESULTS: Friedman test identified significant differences in direct healthcare cost of test 1 (p