Role of Neodymium Double Frequency Laser Posterior Hyaloidotomy in Delayed Presentation of Sub-hyaloid Haemorrhage.

Laser hyaloidotomy with Nd: YAG or green argon laser is a non-invasive, out-patient procedure in which the posterior hyaloid face is punctured and the opening enables the drainage of sub-hyaloid haemorrhage into the vitreous. The blood is absorbed gradually and vision is improved within days with gradual clearance of the macular area. Researchers recommend laser treatment in recent haemorrhages (<2 weeks) while for delayed cases invasive surgeries are advised. We report a case of delayed presentation of sub-hyaloid haemorrhage (>3 weeks) treated successfully with laser hyaloidotomy.

Precision of manual landmark identification between as-received and oriented volume-rendered cone-beam computed tomography images.

INTRODUCTION: The objective of this study was to evaluate the effect of the orientation of cone-beam computed tomography (CBCT) images on the precision and reliability of 3-dimensional cephalometric landmark identification. METHODS: Ten CBCT scans were used for manual landmark identification. Volume-rendered images were oriented by aligning the Frankfort horizontal and transorbital planes horizontally, and the midsagittal plane vertically. A total of 20 CBCT images (10 as-received and 10 oriented) were anonymized, and 3 random sets were generated for manual landmark plotting by 3 expert orthodontists. Twenty-five landmarks were identified for plotting on each anonymized image independently. Hence, a total of 60 images were marked by the orthodontists. After landmark plotting, the randomized samples were decoded and regrouped into as-received and oriented data sets for analysis and comparison. Means and standard deviations of the x-, y-, and z-axis coordinates were calculated for each landmark to measure the central tendency. Intraclass correlation coefficients were calculated to analyze the interobserver reliability of landmark plotting in the 3 axes in both situations. Paired t tests were applied on the mean Euclidean distance computed separately for each landmark to evaluate the effect of 3-dimensional image orientation. RESULTS: Interobserver reliability (intraclass correlation coefficient, >0.9) was excellent for all 25 landmarks for the x-, y-, and z-axes on both before and after orientation of the images. Paired t test results showed insignificant differences for the orientation of volume-rendered images for all landmarks except 3: R1 left (P = 0.0138), sella (P = 0.0490), and frontozygomatic left (P = 0.0493). Also midline structures such as Bolton and nasion were plotted more consistently or precisely than bilateral structures. CONCLUSIONS: Orientation of the CBCT image does not enhance the precision of landmark plotting if each landmark is defined properly on multiplanar reconstruction slices and rendered images, and the clinician has sufficient training. The consistency of landmark identification is influenced by their anatomic locations on the midline, bilateral, and curved structures.

A study of interleukin 1ß levels in peri-miniscrew crevicular fluid (PMCF).

BACKGROUND: This study provides a vital insight in assessing the clinical and biochemical changes in interleukin (IL)-1ß levels in peri-miniscrew crevicular fluid (PMCF) during the course of orthodontic tooth movement. METHODS: The study comprised the analysis of IL-1ß in peri-miniscrew crevicular fluid obtained from crevices around the miniscrews inserted in 11 patients (eight females and three males, mean age 17.3 ± 4.64 years) with all first premolar extraction and maximum anchorage requirement using miniscrew-supported anchorage. Miniscrews were loaded at 3 weeks after placement by 200-g nitinol closed coil springs of 9-mm length for en masse retraction. Peri-miniscrew crevicular fluid was collected at miniscrew placement (T1), at 3 weeks (T2/baseline) and on loading at 0 (T3) and 1 day (T4), 21 (T5), 72 (T6), 120 (T7), 180 (T8) and 300 (T9) days. IL-1ß levels were estimated by enzyme-linked immunosorbent assay (ELISA). Peri-miniscrew tissue was examined for signs of inflammation, and also, miniscrew mobility was assessed with Periotest and handles of two mouth mirrors. RESULTS: IL-1ß levels in all miniscrews were significantly higher at T1 and peaked again at T4 showing a bimodal peak. However, there was a gradual and statistically significant decrease in IL-1ß till T5, while further changes till the end of the study were statistically not significant. CONCLUSIONS: The changing levels of IL-1ß levels in PMCF over a duration of 300 days are suggestive of the underlying inflammatory process. IL-1ß levels in PMCF show a significant rise during miniscrew insertion and on immediate loading. The trend of gradually reducing IL-1ß levels around the miniscrew over the period after loading towards baseline is suggestive of adaptive bone response to stimulus.