Irregularity Index Research Articles

Effects of Recent/Healed Post-Extraction Protocols on Incisor and Canine Alignment During Fixed Orthodontic Appliance Therapy

The purpose of this study was to determine the effects of recent/healed post-premolar extraction protocol, gender, age, and dental arch on incisor and canine alignment during fixed orthodontic appliance therapy. The study sample consisted of 50 dental arches of patients undergoing fixed orthodontic appliance therapy. The arches were randomized into an equal number of recent and healed extraction groups. The orthodontic setup was instituted within 3-7 days and 5-6 weeks following first premolar teeth extractions in the recent and healed extraction groups, respectively. Orthodontic tooth alignment was carried out using 0.016-inch NiTi wires for 16 weeks. Study casts were made at baseline, 4, 8, 12-, and 16-week follow-up treatment. Little's Irregularity Index was used to assess orthodontic tooth alignment. Mann-Whitney U test was used to compare the alignment rates between groups, and multiple linear regression was used to predict the relationship of groups and sociodemographic factors to alignment rate. The statistical significance level was set at P < .05. The mean daily incisor and canine alignment rates in the recent and healed extraction cases were 0.13 mm and 0.11 mm, respectively (P = .332), 0.12 mm in both males and females (P = .827), and 0.13 mm and 0.12 mm in the maxilla and mandible, respec- tively (P = .534). There was however a significant difference in the mean daily alignment rate between adolescents (0.15 mm) and adults (0.10 mm) (P = .019). The rate of incisor and canine alignment was not affected significantly by recent/healed post-extraction protocol, gen- der, and dental arch. However, the rate was significantly faster in adolescents.

Influence of the topography of stratovolcanoes on the propagation and channelization of dense pyroclastic density currents analyzed through numerical simulations

We applied systematically the branching energy cone model to a large ( $$N=50$$ ) set of stratovolcanoes around the world in order to evaluate the main topographic characteristics that may control the propagation of dense pyroclastic density currents (PDCs). Results indicate that the channelization efficiency of a PDC is strongly controlled by the relative scale between flow size and volcano topographic features. Most of the studied stratovolcanoes topographies are able to induce significant PDC channelization in proximal domains, while strong channelization in distal zones is mainly observed for volcanoes with steep flanks, with long, uninterrupted valleys, and with catchments zones of pyroclastic material (i.e. the valleys heads) located near the source. From the statistical analysis of numerical results, we recognise five groups of stratovolcanoes in terms of the mode of interaction between their topographies and dense PDCs: (1) intense channelization through different valleys up to distal domains (e.g. Colima and Peteroa); (2) intense channelization through a single, dominant valley up to distal domains (e.g. Reventador and Mt. St. Helens); (3) intense channelization near the source and moderate distal channelization, frequently involving intertwined drainage networks (e.g. Tungurahua and El Misti); (4) potentially intense channelization only near the source, typically involving flat distal topographies (e.g. Sinabung and Mayon); and (5) weak channelization in proximal domains, resulting in efficient early energy dissipation and thus reduced PDC run-out distance (e.g. Kelut and Akagi). The relevance of this classification lies in the possibility of defining volcanic analogues (defined here as volcanoes that share a suite of topographic characteristics and may be considered comparable to a certain extent) and identifying the main processes that may affect PDC propagation in specific topographic contexts. These aspects are useful for studying poorly documented volcanic edifices and for volcanic hazard assessment. Additionally, we compare this classification with published morphometric characteristics of volcanoes, showing morphometric parameters such as the mean slope of the low flank, irregularity index, ratio of volcano height and basal width and ratio of crater width and basal width are useful variables for recognising the groups we defined. These parameters can be used as rough indicators of the expected interaction patterns between the topography of a given volcano and dense PDCs.

Effects of various analgesics on pain perception and rate of tooth movement: a randomized controlled clinical study

Background: Pain is one of the most reported side effects of orthodontic treatment despite the advanced technology in orthodontics. Many analgesics have been introduced to control orthodontic pain including acetaminophen and selective and nonselective nonsteroidal anti-inflammatory drugs. The great concern about these drugs is their adverse effect on rate of teeth movement. Aims: The purpose of this study was to evaluate and compare the effect of acetaminophen, ibuprofen and etoricoxib on pain perception and their influence on the rate of teeth movement during leveling and alignment stage. Methods: Forty patients were evenly and randomly distributed in a blinded way to one of four groups: placebo (starch capsules), acetaminophen 500mg thrice daily, ibuprofen 400mg thrice daily, and etoricoxib 60mg once daily. The drugs were given one hour before bonding and archwire placement and continued for three days. A visual analogue scale was used to express pain levels before and after archwire placement, on the first, second, third, and seventh day. Little’s irregularity index was measured before bonding and at every activation visit until the end of the alignment and leveling stage. Results: All three drugs showed a lower pain level than placebo at the bonding and first activation visits. Etoricoxib showed the least pain level among other drugs followed by ibuprofen. No statistically significant differences were found between the drug groups and the placebo at the second and third activation visits. No statistically significant differences were detected between the 4 experimental groups concerning the rate of teeth movement. Conclusions: The three drugs were only effective in controlling pain during the first two visits of orthodontic treatment; and etoricoxib 60mg/day was the best. All three drugs had no influence on rate of teeth movement when used in their least recommended dose.

A new shoreline change assessment approach for erosion management strategies

Shoreline evolution studies are fundamental to assess the rate of beach accretion or retreatment. In the last years, researchers developed many methods with several techniques belonging to different disciplines and backgrounds. Nowadays, the Shoreline Change Analysis (SCA) is the most widespread method to assess shoreline evolution. In fact, the SCA is needed to perform management strategies able to respond to current erosion or potential future erosion problems. This paper presents a new approach using an automatic method for SCA with accuracy and speed improvements. Indeed, in the framework of the management of coastal erosion and to develop an adaptation plan to coastal hazards it is necessary to study the links existing between coastal and marine morphological transformations. A new tool was written in Matlab, the input files were built using a GIS environment and the results were arranged in a GIS project. The present tool adopts two approaches: the Transect Based Analysis (TBA) and the Area Based Analysis (ABA). New roughness and irregularity indexes were defined to calculate the transects’ spacing. Moreover, a piecewise polynomial baseline was defined to improve accuracy in shoreline position assessment. The approaches TBA and ABA were validated both by synthetic benchmarks and by a study case. The adopted synthetic benchmarks represent very common types of beaches: with one or more salients, with cusps and groynes. The case study was a logarithmic spiral Mediterranean beach on the southwestern coast of Sicily. All the studied test cases provided good results in terms of accuracy and easiness of use. The new tool and methodology, with TBA and ABA coupling, encloses many practical aspects. Indeed, ABA allows the general assessment of advancing/retreating beach areas, whereas TBA is needed to study very short stretches of beach. The proposed SCA analysis is useful for the requirements of a complete coastal management plan and to evaluate erosion management options. Moreover, the SCA gives a sound technical understanding of the physical coastal processes and should engage the community, the stakeholders and the agencies responsible for development application decisions. The new approach gives high-quality results achieved with significant speediness making it suitable for regional studies and directly providing parameters needed for erosion managing strategies.

Improving keratoconus management with central cor neal regularization and corneal collagen cross-linking protocol treatment.

To evaluate safety and efficacy of customized central corneal regularization (CCR), together with simultaneous accelerated corneal collagen cross-linking (A-CXL) - CCR-CXL protocol, to treat keratoconus-related corneal ectasia. Retrospective, comparative observational case series. Patients that had undergone combined CCR-CXL protocol. Main inclusion criteria were keratoconus visual acuity deterioration and contact lens intolerance. All patients underwent complete ophthalmological evaluation, corrected distance visual acuity (CDVA) and Scheimpflug-corneal tomography. Central corneal regularization was performed by ablation using flying spot laser. Subsequently, the stroma was saturated with 0.17% riboflavin-5-phosphate added every 2 minutes, followed by A-CXL 9 mW/cm2 for 10 minutes. CDVA, medium keratometry value (Kmed), and total corneal morphological irregularity index (CMI) of patients were analyzed before surgery and after 1, 3 and 12 months. A P value of .05 or less was considered statistically significant. 46 eyes of 39 keratoconus patients were treated. At 1 month, the mean CDVA (LogMar) increased from 0.19 ± 0.02 to 0.12 ± 0.02 (P < .05), and the difference remained stable at month 12. Kmax decrease was statistically significant from 57.02 ± 5.65 to 50.21 ± 4.48 (P < .05). CMI decreased significantly from 47.8 ± 2.84 to 30.1 ± 2.4 (P < .01). CCR-CXL protocol is safe and effective in arresting keratectasia progression and increasing corneal optic regularity in keratoconus. These findings showed a significant improvement in CDVA, keratometry values and corneal optical aberrations after being treated with the CCR-CXL protocol.

Evaluation of the effectiveness of modified aligner appliance with nickel-titanium springs in treatment of mild crowding of lower incisors: A randomized controlled clinical trial

This study aimed to evaluate the effectiveness of modified aligner appliances with nickel-titanium springs (MAAs) in treating mild mandibular crowding and assess the overall alignment treatment duration, alignment improvement percentage, and mandibular incisor proclination. This two-armed, parallel-group randomized controlled trial included 36 patients (7 men, 29 women) with mild mandibular incisor crowding according to Little's Irregularity Index. Patients were randomly assigned to two groups: the MAA group (mean age=22.56 ± 3.50 years) and the conventional fixed bracket group (control group; mean age=20.89 ± 2.90 years). The duration of alignment treatment of the lower anterior teeth was calculated. The progress of alignment was evaluated every 2 weeks on the study casts, which were taken at fixed intervals: pretreatment (T0) and 2 (T1), 4 (T2), 6 (T3), and 8 (T4) weeks after beginning the treatment. Change of mandibular incisor proclination was evaluated by measuring and comparing pretreatment and postalignment lateral cephalograms. No statistically significant difference was detected between the two groups in terms of alignment treatment duration (P=0.097), whereas a significant difference was observed in the alignment improvement percentage at T1 (P=0.000), T2 (P=0.001), and T3 (P=0.022). In addition, the MAA group had a lower change of mandibular incisor proclination than the control group (P=0.000). The clinical application of MAAs may be effective in lower incisor decrowding, with a reduction in lower incisor inclination compared with conventional fixed brackets. This trial was registered at ClinicalTrials.gov (identifier: NCT04988373).

Visual Reassessment with Flux-Interval Plot Configuration after Automatic Classification for Accurate Atrial Fibrillation Detection by Photoplethysmography.

Atrial fibrillation (AFib) is a common type of arrhythmia that is often clinically asymptomatic, which increases the risk of stroke significantly but can be prevented with anticoagulation. The photoplethysmogram (PPG) has recently attracted a lot of attention as a surrogate for electrocardiography (ECG) on atrial fibrillation (AFib) detection, with its out-of-hospital usability for rapid screening or long-term monitoring. Previous studies on AFib detection via PPG signals have achieved good results, but were short of intuitive criteria like ECG p-wave absence or not, especially while using interval randomness to detect AFib suffering from conjunction with premature contractions (PAC/PVC). In this study, we newly developed a PPG flux (pulse amplitude) and interval plots-based methodology, simply comprising an irregularity index threshold of 20 and regression error threshold of 0.06 for the precise automatic detection of AFib. The proposed method with automated detection on AFib shows a combined sensitivity, specificity, accuracy, and precision of 1, 0.995, 0.995, and 0.952 across the 460 samples. Furthermore, the flux-interval plot configuration also acts as a very intuitive tool for visual reassessment to confirm the automatic detection of AFib by its distinctive plot pattern compared to other cardiac rhythms. The study demonstrated that exclusive 2 false-positive cases could be corrected after the reassessment. With the methodology’s background theory well established, the detection process automated and visualized, and the PPG sensors already extensively used, this technology is very user-friendly and convincing for promoted to in-house AFib diagnostics.

Mechanical properties and clinical performance of different brands of nickel titanium archwires following intraoral use

Objectives: To evaluate the effect of intraoral use of three brands of nickel titanium archwires on their mechanical properties and crowding relief ability. Methods: Three groups (n=39) of 0.016” round NiTi archwires: Dentaurum (A), American Orthodontics (B) and IMD Orthodontics (C) were subdivided according to the intervention (n=13) into: As-received, no intervention (subgroup 1), in-vivo (subgroup 2), and in-vitro (subgroup 3). Plateau slope, resilience, and elastic modulus of all wires were tested using a universal testing machine. The relief of crowding following intraoral use for 8 weeks was assessed using Little’s irregularity index. Results were significant at p ≤ 0.05. Results: For all NiTi brands, the highest plateau slope value; among the subgroups, was recorded following the intraoral use (in-vivo). For the in-vivo wires (subgroup 2), the Dentaurum wires revealed the lowest plateau slope value (0.258 N/mm ±0.032) while the IMD wires revealed the lowest resilience values (36.24 J.mm-3 ±0.6). There was no significant difference in the modulus of elasticity of wires between all 3 subgroups. The Little’s irregularity index decreased over time, and the difference between the groups was not significant. No significant difference was found between the groups in terms of inter-canine width.

Topological Study of 6.82 D Carbon Allotrope Structure

Carbonallotropes are widely available and can be found in the atmosphere, the earth’s crust, and in living creatures in myriad forms. Allotropes are also used in several fields, including for medicinal and biological applications, due to their intriguing properties such as low resistance, high electron mobility, abnormal quantum hall effect, unconventional superconductivity in graphene, and so on. The theoretical analysis of carbon allotropes can hence be quite useful as it leads to a better understanding of the nature and behavior of these ubiquitous materials and also opens the door for even better applications. The objective of this research is to theoretically analyze the 6.82 carbon allotrope by using four kinds of vertex degree based (VDB) topological indices (Tis), namely VDB multiplicative topological indices, VDB indices using M-Polynomial, VDB entropy measures, and irregularity indices. This analysis will extend the current body of knowledge available for this allotrope and help future researchers in the synthesis of new allotropes.

Preoperative ocular coherence tomographic prognosticators of visual acuity after idiopathic epiretinal membrane surgery.

To provide a current review of the evidence for the utility of preoperative ocular coherence tomography (OCT) parameters in prognosticating postoperative visual acuity and visual improvement after idiopathic epiretinal membrane surgery. To determine which OCT bio-markers are most useful in this regard and where future studies may apply more emphasis. An extensive search of the PubMed database was performed for studies investigating this relationship. Key search terms included: idiopathic, epiretinal membrane, surgery, peel, vitrectomy, vision, outcomes, visual acuity, ocular coherence tomography, central foveal thickness, foveal contour, foveal morphology, ectopic inner foveal layers, inner retinal layers, inner retinal irregularity index, outer retinal layers, ellipsoid zone, interdigitation zone, photoreceptor outer segment length, central bouquet abnormality, staging, choroidoscleral irregularity, ganglion cell and nerve fibre layers, inner and outer plexiform layers, inner and outer nuclear layers. Forty-nine peer-reviewed articles were included in this review. These consisted of 28 retrospective studies [1-3,13,16-18,20,23-29,32-36,38,40,42-47], 17 prospective studies[6-12,14,19,21,22,30,31,37,41,48,49], 2 reviews [4,39] and 2 systematic reviews [5,15]. The weight of literary evidence seems to support photoreceptor integrity as the most consistent OCT marker of better postoperative visual acuity. This includes analysis of ellipsoid and interdigitation zones as well as photoreceptor outer segment length. However, the newer OCT staging system proposed by Govetto et al. (2017) fulfils a need for a clinically useful and evidence-based OCT classification. It may be the way forward in prognosticating ERM surgical outcomes by preoperative stratification. There is insufficient evidence to suggest the other discussed parameters in this review as useful prognosticators of postoperative visual acuity.

Evaluation of efficacy of different types of retainers post orthodontic treatment

Aim: Purpose of this study was to evaluate the efficacy of 3 different types of retainers (Hawley removable, Essix removable and Fixed) of the mandibular and maxillary anterior sextant and to assess patient perception of crowding. Methodology: A retrospective study of 80 patients was carried out for a time period of 1-2 years into retention. E models (digital models) were assessed pre- and post-orthodontically using Little’s Irregularity Index. The amount of Irregularity was compared for 3 retention groups (Hawley, Essix and Fixed). Relapse was also subjectively measured. Results: Increase in the Irregularity Index of the mandibular incisors was observed after wearing Hawley retainers, including crowding which was significantly more than patients with Fixed retainers. Conclusion: Hawley retainers allow for more mandibular incisor movement rather than the Fixed retainers.

Efficacy of fixed versus removal retianer post orthodontic treatment

The dearth of prolonged, prospective evaluation, the relative impact of fixed and the removable retainers eventualities can only be speculated upon. Hence in this study was to compare the stability of orthodontic outcomes with fixed and removable retainers over a period of at least 4 years. Of the 82 participants included in the previous RCT, data were obtained from 48 at 18-month follow up. Orthodontic stability was based chiefly on the irregularity of the mandibular incisors using Little’s Irregularity Index to assign a cumulative score for the contact point displacement in 4 the mandibular inter-canine region. Eighty-two participants were enrolled in the original RCT. After adjusting for confounders, the median between-groups difference was 1.64mm higher in those wearing vacuum-formed retainers (P= 0.02; 95% CI: 0.30, 2.98mm). No statistical difference was found between the treatment groups in terms of inter-canine (P= 0.52; 95% CI: -1.07, 0.55) and inter-molar widths (P= 0.55; 95% CI: -1.72, 0.93), arch length (P= 0.99; 95% CI: -1.15, 1.14) and extraction space opening (P= 0.84; 95% CI: -1.54, 1.86).

Evaluation of Ocular Higher-Order Aberrations in First-Degree Relatives of Patients With Keratoconus.

The aim of this study was to evaluate the corneal higher-order aberrations (HOAs) in first-degree relatives of patients with keratoconus (KCN) and compare with the normal population. In this prospective comparative study, 210 eyes from 105 family members of 28 patients with KCN and 210 normal eyes of 105 controls were enrolled. In each eye, corneal topography, tomography, and aberrometry were performed and compared between the 2 groups. This study included 61 female (58.1%) and 44 male participants (41.9%) and 105 age-matched and sex-matched controls with normal topographic cornea. In 14 of 105 first-degree relatives (13.33%) of patients with KCN, KCN was diagnosed with a male preponderance (71.5% male, 28.5% female). Tomographic indices and irregularity indices in 3 and 5 mm zone in Orbscan were significantly higher in the relative group. In addition, other irregularity indices of TMS-4 topography including surface regularity index, surface asymmetry index, difference sector index, SDP, and irregular astigmatism index were significantly higher in family members of patients with KCN. The most prevalent topographic pattern in the control group was the symmetric bowtie (57.1%) and in the relative group was the asymmetric bowtie (39.5%). In addition, significantly thinnest corneal pachymetry was detected in the relative group. Root mean square of all HOAs including vertical trefoil, vertical coma, horizontal coma, horizontal trefoil, quadrifoil, and fourth-order spherical aberrations were significantly greater in the relative group than controls. Owing to the high prevalence of undiagnosed KCN susceptibility in family members with KCN, keratorefractive surgery should be considered cautiously in these individuals. In addition, comprehensive preoperative examination should be considered to detect subtle topographic and HOAs in these individuals.

Use of 6 Nucleotide Length Words to Study the Complexity of Gene Sequences from Different Organisms.

In this paper, we attempted to find a relation between bacteria living conditions and their genome algorithmic complexity. We developed a probabilistic mathematical method for the evaluation of k-words (6 bases length) occurrence irregularity in bacterial gene coding sequences. For this, the coding sequences from different bacterial genomes were analyzed and as an index of k-words occurrence irregularity, we used , which has a distribution similar to normal. The research results for bacterial genomes show that they can be divided into two uneven groups. First, the smaller one has W in the interval from 170 to 475, while for the second it is from 475 to 875. Plants, metazoan and virus genomes also have W in the same interval as the first bacterial group. We suggested that second bacterial group coding sequences are much less susceptible to evolutionary changes than the first group ones. It is also discussed to use the W index as a biological stress value.

An Observed Trend Between Mid‐Latitudes Km‐Scale Irregularities and Medium‐Scale Traveling Ionospheric Disturbances

AbstractWe describe observations of a trend between the level of km‐scale irregularity activity and the amplitudes of medium‐scale traveling ionospheric disturbances (MSTIDs) at mid‐latitudes using data from December 2019 through June 2021. These include measurements of both heigh‐specific and vertically integrated quantities. Region‐specific, bottom‐side measurements were made with the dynasonde system near Wallops Island (WI) and included phase structure function parameters related to km‐scale irregularities as well as height‐specific tilts/density gradients, which are especially sensitive to MSTIDs. A complementary data set was derived from the nearby Deployable Low‐band Ionosphere and Transient Experiment (DLITE) array in southern Maryland. The DLITE array was used to measure the vertically integrated irregularity index, CkL, via scintillometry of bright cosmic radio sources at 35 MHz. Transverse gradients in the line‐of‐sight total electron content (TEC) were also measured with DLITE using apparent shifts in the sources' sky positions. Relatively simple layer‐based models for the vertical distribution of km‐scale irregularities applied to dynasonde‐measured properties yielded results that correlated well with DLITE measurements of CkL. Similarly, spectral analysis showed that fluctuation amplitudes of vertically integrated bottom‐side density gradients derived from dynasonde data were well correlated with DLITE TEC gradient measurements. A significant trend was found between CkL and TEC gradient MSTID amplitudes among DLITE‐based data as well as among the extrapolated dynasonde measurements. Additionally, within the bottom‐side F‐region, irregularity levels were found to be well correlated with fluctuation amplitudes for the tilt as measured with the WI dynasonde.

Irregularity Index for Vector-Valued Morphological Operators

Mathematical morphology is a valuable theory of nonlinear operators widely used for image processing and analysis. Although initially conceived for binary images, mathematical morphology has been successfully extended to vector-valued images using several approaches. Vector-valued morphological operators based on total orders are particularly promising because they circumvent the problem of false colors. On the downside, they often introduce irregularities in the output image. This paper proposes measuring the irregularity of a vector-valued morphological operator by the relative gap between the generalized sum of pixel-wise distances and the Wasserstein metric. Apart from introducing a measure of the irregularity, referred to as the irregularity index, this paper also addresses its computational implementation. Precisely, we distinguish between the ideal global and the practical local irregularity indexes. The local irregularity index, which can be computed more quickly by aggregating values of local windows, yields a lower bound for the global irregularity index. Computational experiments with natural images illustrate the effectiveness of the proposed irregularity indexes.

Effect of piezocision procedure in levelling and alignment stage of fixed orthodontic treatment: a randomized clinical trial

This clinical trial compared the time to complete the levelling and alignment stage with flapless piezocision procedure in the treatment of severe maxillary malocclusion with premolar extraction cases. Two-arm parallel group randomized controlled trial was performed at the Orthodontics Unit of Universiti Sains Malaysia, Malaysia. Sixteen patients with severe anterior maxillary crowding (Little’s irregularity index: 7–9 mm) and required bilateral first premolars extraction was recruited. The participants were randomly assigned to a study group according to a simple randomization method using a sealed envelope mentioned about the group name. Both groups were treated with fixed orthodontic appliance using the 0.022-in. slot of McLaughlin Bennett Trevisi prescription brackets. The piezocision group received flapless piezocision corticotomy about 4–5 mm in length and 3 mm depth on the labial mucogingiva between the roots of six anterior teeth. The number of days since treatment started, Little’s irregularity index, gingival recession, pocket depth, pulp vitality, patient perception of the pain and satisfaction level were recorded before the treatment, at about 1 month and 2 months post-treatment, and at the completion of the levelling and alignment stage. The overall time to complete levelling and alignment stage was significantly shorter in the piezocision group than the control group (mean difference = 31.5 days, 95% CI 6.5, 56.5; p = 0.018). Greater reduction in Little’s irregularity index and faster alignment rate in the first 2 months were found in the piezocision group compared to the control group (p < 0.05). No changes in the gingival recession, pocket depth, and pulp vitality in both groups were observed. Patients who received piezocision surgery experienced no or mild pain and were satisfied with the treatment. Flapless piezocision corticotomy is an effective adjunct that shortens treatment time during levelling and alignment stage without any adverse effects on the teeth and surrounding tissues. It is also painless, acceptable and satisfactory to the patients.Trial registration: ACTRN12621001350819.

The Effects of Increased Maxillary Canine Bracket Angulation on Tooth Movement and Alignment Efficiency: A Prospective Clinical Study.

This study aimed to evaluate the effects of a 10° angulation of a maxillary canine (Mx3) bracket on Mx3 and maxillary central incisor (Mx1) tooth movements and alignment efficiency in treatments involving maxillary premolar extraction. This split-mouth study included 29 individuals in a +10° angulation study group and a 0° angulation control group. The initial (T0) and 12th week (T1) orthodontic models were prepared and digitized with a three-dimensional scanner and superimposed using the OrthoAnalyzer analysis program. The movements of Mx3 and Mx1 were measured, and the alignment efficiency was assessed using Little's Irregularity Index. The Shapiro-Wilk test was used to test the data for a normal distribution. T1 and T0 measurements within the group and T1 and T0 differences between groups were compared using a paired samples t-test. The significance level was set to P < .05. The linear movements of Mx3 in the distal direction significantly increased, and Little's Irregularity Index values statistically significantly decreased in both groups. Distal movements of Mx3 were significantly higher in the control group than in the study group (P< 0.01 and P< 0.05). The movements of Mx1 and Little's Irregularity Index measurements did not show statistically significant differences between the groups (P > 0.05). A +10° Mx3 bracket angulation increased the inclination of Mx3 to the mesial, but it decreased the Mx3 distal linear movement and the retraction of Mx1, with no difference in terms of alignment efficiency between the+10° and 0° Mx3 bracket angulations.

The IRC Indices of Transformation and Derived Graphs

An irregularity index IR(Γ) of a graph Γ is a nonnegative numeric quantity (i.e., IR(Γ)≥0) such that IR(Γ)=0 iff Γ is a regular graph. In this paper, we show that IRC closely correlates with the normal boiling point Tbp and the standard heat of formation ΔHfo of lower benzenoid hydrocarbons. The correlation models that fit the data efficiently for both Tbp and ΔHfo are linear. We develop further mathematical properties of IRC by calculating its exact expressions for the recently introduced transformation graphs as well as certain derived graphs, such as the total graph, semi-total point graph, subdivision graph, semi-total line graph, double, strong double, and extended double cover graphs. Some open problems are proposed for further research on the IRC index of graphs.

Effect of low-level laser therapy on the time needed for leveling and alignment of mandibular anterior crowding.

To assess the effect of low-level laser therapy (LLLT) on overall leveling and alignment time of mandibular anterior crowding and associated pain after initial archwire placement. Thirty-two females (18-25 years) with mandibular anterior crowding were randomly allocated into laser and control groups. Eligibility criteria included Angle Class I molar relationship and Little's irregularity index (LII) from 4 to 10 mm. Randomization was accomplished with a computer-generated random list. A 0.014-inch copper-nickel-titanium (Cu-NiTi) wire was inserted immediately after bonding of 0.022-inch Roth brackets followed by 0.016-inch Cu-NiTi, 0.016 × 0.022-inch NiTi then 0.017 × 0.025-inch stainless steel wire after completion of alignment. In-Ga-As laser was applied to the mandibular anterior segment in the laser group on days 3, 7, and 14, then at 1 month followed by every 2 weeks until completion of leveling and alignment. Visual analogue scale questionnaires were completed by each patient over 7 days from initial archwire placement. Digital models were used to monitor changes in the irregularity index. Blinding was applicable for outcome assessors only. The mean time for leveling and alignment was significantly lower in the laser compared to the control group (68.2 ± 28.7 and 109.5 ± 34.7 days, respectively). The laser group displayed a significantly higher mean alignment improvement percentage as well as lower pain scores compared to the control group. Within the constraints of the current study, LLLT has a potential for acceleration of anterior segment alignment as well as reduction of the pain associated with placement of initial archwires.