An Evaluation of Microbial Flora, Alkaline Phosphatase and IL-8 Levels in GCF of Orthodontic Patients with Self-Ligating and Conventional Brackets.

PURPOSE: To compare the microbial flora, alkaline phosphatase (ALP) and interleukin-8 (IL-8) levels during orthodontic treatment with self-ligating brackets versus conventional brackets. PATIENTS AND METHODS: Forty patients were included in this study and distributed equally between two groups. One group received conventional edgewise brackets while the other group received DAMON self-ligating brackets. Periodontal parameters were recorded and biochemical and microbial analyses were conducted before bonding (baseline), and 14, 30, and 45 days after bonding. Paired t-test was performed to estimate the intergroup differences from the baseline at the various time points; unpaired t-test was used for intragroup comparisons. RESULTS: A significantly higher prevalence of gram-negative as well as gram-positive microorganisms was found in the group with conventional brackets than that with self-ligating brackets. Alkaline phosphatase (ALP) activity and interleukin-8 (IL-8) levels were significantly higher in the gingival crevicular fluid of the group with conventional brackets than that with self-ligating brackets. CONCLUSION: The conventional bracket-ligature technique exhibited an increase in IL-8 levels, ALP activity, and microbial colonization compared with that of the self-ligature technique. Accordingly, self-ligating brackets are recommended in orthodontic patients to improve periodontal health and minimize damage outcomes of periodontal tissue interventions.

Malocclusion and Craniofacial Characteristics in Saudi Adolescents with Sickle Cell Disease.

BACKGROUND: Sickle cell disease can result in dentofacial abnormalities. However, in Saudi Arabia, there are limited data with respect to orthodontic manifestations in patients with sickle cell disease. OBJECTIVE: To determine the malocclusion and craniofacial characteristics in sickle cell disease adolescents and compare them with that of controls from the Eastern Province of Saudi Arabia. METHODS: This comparative cross-sectional study included 112 Saudi patients with sickle cell disease, aged 12-18 years, and 124 age-matched Saudi controls from three major hospitals in Al Khobar and Dammam, Saudi Arabia. The Dental Aesthetic Index was used to assess malocclusion and orthodontic treatment needs. Digital lateral cephalometric radiographs were recorded for each patient and control, and its analysis included linear and angular measurements. RESULTS: The prevalence of malocclusion was 87.5% in sickle cell disease patients and 54% in controls (P = 0.0001). The percentage of sickle cell disease patients with severe malocclusion that required orthodontic treatment was higher than that of controls (37.5% vs. 26.6%). In the sickle cell disease cohort, incisal segment crowding (72.4%), overjet (67.3%) and maxillary misalignment in the anterior segment (56%) were the most prevalent types of malocclusions and were significantly higher than that of controls (P < 0.05). About 38% and 67% of the sickle cell disease patients had openbite and posterior crossbite, respectively, compared with 19.3% (P = 0.001) and 37.1% (P = 0.0001) of controls, respectively. Cephalometric analysis showed that SNA (86.7°) and ANB (9.9°) angles were significantly higher in sickle cell disease patients than in controls (81.5° and 2°, respectively). In addition, lower central incisor-to-Frankfort horizontal plane (55°) and interincisal angles (121.5°) were significantly lower in sickle cell disease patients than in controls. CONCLUSION: Adolescents with sickle cell disease had a higher prevalence of malocclusion and greater orthodontic treatment needs than controls. Similarly, they had greater incisal crowding, overjet, openbite and posterior crossbite and demonstrated higher SNA, ANB and lower interincisal angles than controls. The findings of this study suggest that adolescents with sickle cell disease should be provided frequent dental examinations and early orthodontic treatment to improve their oral health, and thus quality of life.

Parametric Simulations of Slanted 1D Photonic Crystal Sensors.

Photonic crystals and band gap materials act as manipulators of light and have a plethora of applications. They are made up of stacks of alternating dielectric constants. This article shows the simulations of an inclined, one dimensional and tuneble photonic crystal, using numerical finite element methods. The photonic crystal was made up of silver nanoparticles embedded in a hydrogel matrix and it has the ability to change and recover its periodicity. A series of factors concerning the geometry of the lattice were tested in order to analyze the efficiency, performance and optimize the properties of the optical sensor. These factors range from the size of the nanoparticles and their density within the stacks, to observing the effect of diffraction angle in readouts.