Moderate Crowding Research Articles

Determination of Stresses and Forces on the Orthodontic System by Using Numerical Simulation of the Finite Elements Method

This study was addressed to use knowledge about the orthodontic system with numerical simulation of the nite elements method. For the rst time we simulated the stresses on the orthodontic system and, in this manner, calculated the orthodontic force on the tooth. A 3D orthodontic model or orthodontic system was designed resembling moderate crowding in the dental arch with all supporting structures. CATIA V5 computer software was used to set up a model for the orthodontic system and ABAQUS was used for simulation of the stresses on the orthodontic system. Our attention was focused on the stresses on the tooth lateral incisor and its periodontal ligament. The results of the numerical simulation showed complex stresses on the tooth lateral incisor and its periodontal ligament. In this paper is presented a calculation of the orthodontic force acting on the tooth lateral incisor due to the orthodontic wire. This orthodontic force was calculated from the stresses on the bracket. The calculated orthodontic force was in the area which is considered as the optimal orthodontic force for movement of the tooth.

Effects of early bilateral mandibular first molar extraction on condylar and ramal vertical asymmetry

This study aims to investigate the mandibular vertical asymmetry in a group of adult patients who had early bilateral mandibular first molar extractions. Mandibular asymmetry index measurements (condylar, ramal, and condylar plus ramal) were made on the panoramic radiographs of a study group including 30 subjects (mean age, 18.22 ± 1.30 years) and a control group of 25 subjects (mean age, 18.24 ± 1.17 years). Group I comprised the control group patients with no extractions and had excellent class I relationships, no missing teeth, and slight or moderate anterior crowding. Group II included patients with a bilateral mandibular first molar teeth extracted before the age of 12 years. Student's t test was used for the comparison of asymmetry index values between the groups. A paired t test was used to determine possible statistically significant differences between the sides for condylar, ramal, and condylar plus ramal height measurements. No group showed statistically significant side-specific differences for posterior vertical height measurements. Condylar asymmetry index (CAI), ramal asymmetry index, and condylar plus ramal asymmetry index measurements were not statistically different between the groups (p > 0.05). CAI values were significantly high when compared with the 3 % threshold value in the both groups, but comparisons between the groups were not statistically significant. This article investigates the effects of early bilateral mandibular molar teeth extraction that has never been investigated in the literature. The present study showed that the lengths of the condylar, ramal, and condylar plus ramal height were less in the study group than in a well-matched control group of without extraction.

From microscopy data to in silico environments for in vivo-oriented simulations

In our previous study, we introduced a combination methodology of Fluorescence Correlation Spectroscopy (FCS) and Transmission Electron Microscopy (TEM), which is powerful to investigate the effect of intracellular environment to biochemical reaction processes. Now, we developed a reconstruction method of realistic simulation spaces based on our TEM images. Interactive raytracing visualization of this space allows the perception of the overall 3D structure, which is not directly accessible from 2D TEM images. Simulation results show that the diffusion in such generated structures strongly depends on image post-processing. Frayed structures corresponding to noisy images hinder the diffusion much stronger than smooth surfaces from denoised images. This means that the correct identification of noise or structure is significant to reconstruct appropriate reaction environment in silico in order to estimate realistic behaviors of reactants in vivo. Static structures lead to anomalous diffusion due to the partial confinement. In contrast, mobile crowding agents do not lead to anomalous diffusion at moderate crowding levels. By varying the mobility of these non-reactive obstacles (NRO), we estimated the relationship between NRO diffusion coefficient (Dnro) and the anomaly in the tracer diffusion (α). For Dnro=21.96 to 44.49 μm2/s, the simulation results match the anomaly obtained from FCS measurements. This range of the diffusion coefficient from simulations is compatible with the range of the diffusion coefficient of structural proteins in the cytoplasm. In addition, we investigated the relationship between the radius of NRO and anomalous diffusion coefficient of tracers by the comparison between different simulations. The radius of NRO has to be 58 nm when the polymer moves with the same diffusion speed as a reactant, which is close to the radius of functional protein complexes in a cell.

Esthetic orthodontic treatment with a double J retractor and temporary anchorage devices

This clinical article reports an esthetic treatment option for managing a Class II malocclusion in an adult. The patient, a woman aged 24 years 2 months, had crowding and a convex profile. She was treated with maxillary first premolar extractions, a double J retractor, and temporary skeletal anchorage devices in the maxillary arch. Posttreatment records after 2 years showed excellent results with good occlusion and long-term stability.

Occlusal traits of deciduous dentition of preschool children of Indian children

Objectives:To assess the occlusal relationship, canine relationship, crowding, primate spaces, and anterior spacing in both maxillary and mandibular arches of primary dentition of Indian children of Wardha District and also to study the age-wise differences in occlusal characteristics.Materials and Methods:A total of 1053 (609 males and 444 females) children of 3-5 year age group with complete primary dentition were examined for occlusal relationship, canine relationship, crowding, primate spaces, and anterior spacing in both maxillary and mandibular arches.Results:The data after evaluation showed significant values for all parameters except mandibular anterior spacing, which was 47.6%. Mild crowding was prevalent at 5 year age group and moderate crowding was common at 3 year-age group.Conclusion:Evaluated parameters such as terminal molar relationship and canine relationship were predominantly progressing toward to normal but contacts and crowding status were contributing almost equal to physiologic anterior spacing. Five-year-age group showed higher values with respect to all the parameters.

Mini-implant supported molar distalization

Temporary anchorage devices popularly called mini-implants or mini-screws are the latest addition to an orthodontist's armamentarium. The following case report describes the treatment of a 16-year-old girl with a pleasant profile, moderate crowding and Class II molar relationship. Maxillary molar distalization was planned and mini-implants were used to preserve the anterior anchorage. After 13 months of treatment Class I molar and canine relation was achieved bilaterally and there was no anterior proclination. Thus mini-implants provide a viable option to the clinician to carry out difficult tooth movements without any side effects.

Dietary essential amino acids affect the reproduction of the keystone herbivore Daphnia pulex.

Recent studies have indicated that nitrogen availability can be an important determinant of primary production in freshwater lakes and that herbivore growth can be limited by low dietary nitrogen availability. Furthermore, a lack of specific essential nitrogenous biochemicals (such as essential amino acids) might be another important constraint on the fitness of consumers. This might be of particular importance for cladoceran zooplankton, which can switch between two alternative reproductive strategies – the production of subitaneously developing and resting eggs. Here, we hypothesize that both the somatic growth and the type of reproduction of the aquatic keystone herbivore Daphnia is limited by the availability of specific essential amino acids in the diet. In laboratory experiments, we investigated this hypothesis by feeding a high quality phytoplankton organism (Cryptomonas) and a green alga of moderate nutritional quality (Chlamydomonas) to a clone of Daphnia pulex with and without the addition of essential amino acids. The somatic growth of D. pulex differed between the algae of different nutritional quality, but not dependent on the addition of dissolved amino acids. However, in reproduction experiments, where moderate crowding conditions at saturating food quantities were applied, addition of the essential amino acids arginine and histidine (but not lysine and threonine) increased the total number and the developmental stage of subitaneous eggs. While D. pulex did not produce resting eggs on Cryptomonas, relatively high numbers of resting eggs were released on Chlamydomonas. When arginine and histidine were added to the green algal diet, the production of resting eggs was effectively suppressed. This demonstrates the high, but previously overlooked importance of single essential amino acids for the reproductive strategy of the aquatic keystone herbivore Daphnia.

Barriers to Diffusion in Dendrites and Estimation of Calcium Spread Following Synaptic Inputs

The motion of ions, molecules or proteins in dendrites is restricted by cytoplasmic obstacles such as organelles, microtubules and actin network. To account for molecular crowding, we study the effect of diffusion barriers on local calcium spread in a dendrite. We first present a model based on a dimension reduction approach to approximate a three dimensional diffusion in a cylindrical dendrite by a one-dimensional effective diffusion process. By comparing uncaging experiments of an inert dye in a spiny dendrite and in a thin glass tube, we quantify the change in diffusion constants due to molecular crowding as Dcyto/Dwater = 1/20. We validate our approach by reconstructing the uncaging experiments using Brownian simulations in a realistic 3D model dendrite. Finally, we construct a reduced reaction-diffusion equation to model calcium spread in a dendrite under the presence of additional buffers, pumps and synaptic input. We find that for moderate crowding, calcium dynamics is mainly regulated by the buffer concentration, but not by the cytoplasmic crowding, dendritic spines or synaptic inputs. Following high frequency stimulations, we predict that calcium spread in dendrites is limited to small microdomains of the order of a few microns (<5 μm).

P1-6 Measures of socio-demographic factors for child health research

BackgroundH pylori infection is one of the major causes of health problems with considerable morbidity and mortality. H pylori seroprevalence is common in populations with poor standards of sanitation and...

Comparison of the outcomes of the lower incisor extraction, premolar extraction and non-extraction treatments

The aim of this retrospective study was to evaluate the treatment outcome of lower incisor extraction and to compare it with premolar extraction and non-extraction treatment. The sample consisted of 60 subjects with Class I malocclusion and moderate crowding. The sample was separated into three groups: extraction of a lower incisor group, extraction of a four first premolar group and a non-extraction group. All groups involved 13 girls and 7 boys with a total of 20 patients. The Peer assessment rating (PAR) index was applied to a patient's pre-treatment (T1) and post-treatment (T2) dental casts. T1 dental casts were also used for determining Bolton discrepancy. One-way analysis of variance and post hoc Tukey HSD tests were used for statistical analysis. For the mean percentage PAR score reduction for each group, there was one significant difference seen between the lower incisor extraction group and the non-extraction group (P = 0.047). For the mean anterior ratios, there were significant differences among premolar extraction group versus non-extraction group (P = 0.042) and non-extraction group versus lower incisor extraction group (P = 0.000). For the mean overall ratios, there were significant differences among the premolar extraction group versus lower incisor extraction group (P = 0.048) and the non-extraction group versus lower incisor extraction group (P = 0.001). Orthodontic treatment without extraction has a better treatment outcome than the four-first premolar extraction and single lower incisor extraction protocols in Class I cases with moderate to severe mandibular anterior crowding.

Orthodontic management of a case report crowded class iii malocclusion on a class iii skeletal base: a case report.

A late adolescent patient presented with a Class III malocclusion on a skeletal Class III base, complicated by severe upper arch and moderate lower arch crowding, reverse overjet, anterior and bilateral posterior crossbites with displacement, proclined upper incisors, retroclined lower incisors, distally tipped lower canines and non-coincident centrelines. Treatment was undertaken on an extraction basis by employing the use of an upper removable appliance with Z-springs and posterior bite blocks to correct the anterior crossbite, quad helix and jockey arch for arch expansion, and pre-adjusted edgewise fixed appliance to level and align, space closure and achieve a mutually protective functional occlusion. This paper discussed the rational and evidences behind the treatment employed.

Editor's Comment and Q&A: Arch-width and perimeter changes in patients with borderline Class I malocclusion treated with extractions or without extractions with air-rotor stripping

Introduction The aim of this study was to compare dental arch-width and perimeter changes in patients with borderline Class I occlusion, treated with extractions or without extractions with air-rotor stripping (ARS). Methods The study was conducted with 26 sets of pretreatment and posttreatment dental models of patients with borderline Class I occlusion. Thirteen patients (mean age, 18.1 ± 3.7 years) were treated with 4 premolar extractions, and 13 (mean age, 17.8 ± 2.4 years) were treated without extractions but with the ARS technique. Mean maxillary and mandibular crowding values were 5.7 ± 1.5 and 5.9 ± 1.4 mm in the extraction group, and 5.0 ± 1.3 and 5.9 ± 1.3 mm in the nonextraction group, respectively. A digital caliper was used to measure maxillary and mandibular intercanine and intermolar arch widths and arch perimeters. The Wilcoxon test was used to evaluate treatment changes in each group. The Mann-Whitney U test was used to compare the pretreatment and posttreatment values and the treatment changes between the 2 groups. Results At the start of treatment, the maxillary and mandibular intercanine and intermolar widths and the arch perimeters of both groups did not differ statistically. The maxillary intercanine widths were maintained in both groups. The maxillary and mandibular intermolar widths and arch perimeters decreased in the extraction group. In the nonextraction group, intermolar widths decreased, but arch perimeters did not change significantly. After treatment, the maxillary and mandibular intercanine widths were not different between the groups. Conclusions In Class I borderline patients with moderate crowding, extraction therapy with minimum anchorage did not result in narrower dental arches, and nonextraction treatment with ARS preserved the intercanine arch widths and arch perimeters. The aim of this study was to compare dental arch-width and perimeter changes in patients with borderline Class I occlusion, treated with extractions or without extractions with air-rotor stripping (ARS). The study was conducted with 26 sets of pretreatment and posttreatment dental models of patients with borderline Class I occlusion. Thirteen patients (mean age, 18.1 ± 3.7 years) were treated with 4 premolar extractions, and 13 (mean age, 17.8 ± 2.4 years) were treated without extractions but with the ARS technique. Mean maxillary and mandibular crowding values were 5.7 ± 1.5 and 5.9 ± 1.4 mm in the extraction group, and 5.0 ± 1.3 and 5.9 ± 1.3 mm in the nonextraction group, respectively. A digital caliper was used to measure maxillary and mandibular intercanine and intermolar arch widths and arch perimeters. The Wilcoxon test was used to evaluate treatment changes in each group. The Mann-Whitney U test was used to compare the pretreatment and posttreatment values and the treatment changes between the 2 groups. At the start of treatment, the maxillary and mandibular intercanine and intermolar widths and the arch perimeters of both groups did not differ statistically. The maxillary intercanine widths were maintained in both groups. The maxillary and mandibular intermolar widths and arch perimeters decreased in the extraction group. In the nonextraction group, intermolar widths decreased, but arch perimeters did not change significantly. After treatment, the maxillary and mandibular intercanine widths were not different between the groups. In Class I borderline patients with moderate crowding, extraction therapy with minimum anchorage did not result in narrower dental arches, and nonextraction treatment with ARS preserved the intercanine arch widths and arch perimeters.

Arch-width and perimeter changes in patients with borderline Class I malocclusion treated with extractions or without extractions with air-rotor stripping

The aim of this study was to compare dental arch-width and perimeter changes in patients with borderline Class I occlusion, treated with extractions or without extractions with air-rotor stripping (ARS). The study was conducted with 26 sets of pretreatment and posttreatment dental models of patients with borderline Class I occlusion. Thirteen patients (mean age, 18.1 +/- 3.7 years) were treated with 4 premolar extractions, and 13 (mean age, 17.8 +/- 2.4 years) were treated without extractions but with the ARS technique. Mean maxillary and mandibular crowding values were 5.7 +/- 1.5 and 5.9 +/- 1.4 mm in the extraction group, and 5.0 +/- 1.3 and 5.9 +/- 1.3 mm in the nonextraction group, respectively. A digital caliper was used to measure maxillary and mandibular intercanine and intermolar arch widths and arch perimeters. The Wilcoxon test was used to evaluate treatment changes in each group. The Mann-Whitney U test was used to compare the pretreatment and posttreatment values and the treatment changes between the 2 groups. At the start of treatment, the maxillary and mandibular intercanine and intermolar widths and the arch perimeters of both groups did not differ statistically. The maxillary intercanine widths were maintained in both groups. The maxillary and mandibular intermolar widths and arch perimeters decreased in the extraction group. In the nonextraction group, intermolar widths decreased, but arch perimeters did not change significantly. After treatment, the maxillary and mandibular intercanine widths were not different between the groups. In Class I borderline patients with moderate crowding, extraction therapy with minimum anchorage did not result in narrower dental arches, and nonextraction treatment with ARS preserved the intercanine arch widths and arch perimeters.

Helicobacter pylori infection in children: population‐based age‐specific prevalence and risk factors in a developing country

We estimated the prevalence, age of acquisition and risk factors for Helicobacter pylori (H. pylori) seroprevalence in children aged 1-15 years. Exposure was assessed using ELISA. Parents responded to a questionnaire regarding number of individuals sharing house, rooms, water source, latrines, housing and assessment of socioeconomic status (SES) by Hollingshead Index. Serum of 1976 children was tested. Helicobacter pylori seropositivity in children aged 11-15 years was 53.5% (OR: 2.0, 95% CI: 1.58-2.5). It increased with moderate crowding index (CRI) of 2-4 to 45.9% (OR: 1.23, 95% CI: 0.92-1.63) and to 51.2% with CRI >4 (OR: 1.52, 95% CI: 1.12-2.06). In middle SES, seropositivity was 50.5% (331/655) (OR: 1.7, 95% CI: 1.29-2.35), whereas in lower SES, it was 47.1% (500/1062) (OR: 1.5, 95% CI: 1.1-2.0). Multivariate analysis showed that Helicobacter pylori seroprevalence was high in children aged 6-10 and 11-15 years (OR: 1.5, 95% CI: 1.2-1.9 and OR: 1.9, 95% CI: 1.56-2.47 respectively), in lower-middle SES (OR: 1.6, 95% CI: 1.2-2.1 and OR: 1.5, 95% CI: 1.10-2.0 respectively) and in uneducated fathers (OR: 1.58, 95% CI: 1.27-1.95). Helicobacter pylori seropositivity increases with age, in low-middle SES and is related to father's educational status. Reducing H. pylori seroprevalence will require improvement in sanitary conditions and educational status of the population.

The pattern of malocclusion in a sample of orthodontic patients from Turkey

The objective of this study was to determine the prevalence of individual traits of malocclusion in a sample of Turkish orthodontic patients. The present study was based on the examination of dental casts, intraoral photographs and panoramic radiographs of 1507 orthodontic patients (884 females and 623 males). The relationship of the first upper and lower molars according to the Angle's classification, overjet, overbite, crowding, spacing, posterior crossbite, scissor bite, maxillary median diastema were examined. The Pearson chi-squared and Fisher's Exact tests were used to determine potential differences in the distribution of malocclusion when stratified by gender. The study demonstrated that only 52 (3.5%) of the subjects had normal occlusion. Class I malocclusion was found in 626 (41.5%), Class II Division 1 in 435 (28.9%), Class II Division 2 in 142 (9.4%) and Class III malocclusion in 252 (16.7%) subjects of all examined. Normal overbite, normal overjet, crossbite on both sides and severe crowding in the upper dental arch were observed more frequently in females (P<0.05), however, increased overbite and moderate crowding in the upper dental arch were observed more frequently in males (P<0.05). The results of this study showed that crowding in the upper and lower dental arches in a sample of Turkish population was the most frequent of all anomalies recorded with ranges of 70.0% and 47.3%, respectively.

Orthodontic intervention of an impacted upper left central incisor due to odontoma. A case report

Aim: To present a case of a compound odontoma impeding eruption of the permanent upper left central incisor and to narrate its management. Case history: A 12-year-old girl attended at Muhimbili National Hospital dental clinic complaining of a missing upper anterior tooth. At the age of 3 years the patient sustained injury on the anterior part of the upper jaw. A decidous tooth was fractured and eventually extracted. Oral tissues were healthy and the dentition was caries free. Molar relationship on the right-half a unit was class II, on the left full unit class II. Moderate crowding was observed on the upper right and lower right arches, whereas, mild crowding was seen on the lower left arch. No detrimental para functional habits were noted. Radiographic examination revealed the presence of a radiopaque mass with features consistent with an Odontoma, it was overlying an impacted upper left central incisor and had a size of about 4 X 4 mm. Treatment done: The odontoma was surgically removed. A fixed orthodontic appliance was used to facilitate traction and correction of malalignement of the impacted upper left central incisor.Treatment outcome: Successful removal of the odontoma, full exposure of the crown of upper left central incisor and good alignment on the arch were achieved. Crowding on the upper and lower arches was relieved and leveling of both arches together with improvement of midline shift resulted in good facial aesthetics. Conclusion: Successful removal of the impeding odontoma followed by orthodontic management of an impacted incisor with a fixed appliance successfully restored the child’s aesthetics and self esteem.

Long-term soft-tissue response to orthodontic treatment with early cervical headgear—a randomized study

The purpose of this longitudinal randomized investigation was to determine the long-term changes in the soft-tissue profile during orthodontic treatment when treatment is started with headgear (HG) in the early mixed dentition. The subjects were 68 children (28 girls, 40 boys; mean age, 7.6 years; SD, 0.3 years) with a Class II tendency in occlusion and moderate crowding. They were randomly divided into 2 groups. In the HG group, treatment began immediately. No other appliances were used during the first 2 years. In the control group, only minor interceptive procedures were performed during the first follow-up period of 2 years. During the 8-year follow-up, orthodontic treatment, if needed, comprised fixed appliances and possible extractions in both groups. Twenty linear and 5 angular soft-tissue measurements were registered from lateral cephalograms taken before treatment and after follow-up-periods of 2, 4, and 8 years. The major findings were that, at the 8-year follow-up, the soft-tissue chin and the lower lip were significantly thicker, and the mentolabial sulcus was significantly deeper in the HG group than in the control group. In the control group, a larger variation in the upper lip position was found because of more extractions in this group. Early HG treatment has only a minor effect on the soft-tissue profile. The main effects are on the thickness of the soft-tissue chin and the contour of the lower lip. The differences were not otherwise significant during the long-term follow-up.

Early Headgear Effects on the Eruption Pattern of the Maxillary Canines

To test the null hypothesis that early headgear (HG) treatment has no effect on the eruption pattern of the maxillary canines in the early mixed dentition. Sixty-eight children (40 boys and 28 girls) with a Class II tendency in occlusion and moderate crowding of the dental arches were randomized into two groups. HG treatment was initiated immediately in the first group. In the second group only minor interceptive procedures were performed during the first follow-up period of 2 years. Orthopantomograms were taken at the baseline, three times at 1-year intervals, and after growth at the age of 16. Eruption geometry was performed. The space from the maxillary first molar to the lateral incisor was measured on the dental casts. The inclination of the maxillary canine in relation to the midline appeared to be significantly more vertically oriented on the right side in the HG group 1 and 2 years after starting the HG therapy (P = .0098 and P = .0003, respectively). The inclination in relation to the lateral incisors was smaller in the HG group bilaterally after 1 year and 2 years of HG treatment, and on the right side after 3 years of treatment. The hypothesis is rejected. Early HG treatment significantly affects the inclination of the maxillary canine during eruption. The strongest influence was seen after 2 years of HG use, more prominently in the right-side canine.

Nonsurgical treatment of an adult with mandibular asymmetry and unilateral posterior crossbite

The patient was a woman, 24 years 8 months old, with mandibular asymmetry resulting in a unilateral posterior crossbite. In addition to moderate crowding in the mandibular arch, the malocclusion was further complicated by an asymmetric maxillary arch, a consequence of an extracted maxillary left second premolar. The mandibular arch was skewed, and there were severe dental compensations. The patient was treated nonsurgically, with unilateral extractions of teeth and asymmetric mechanics. Pretreatment and posttreatment records are shown, and the treatment strategy resulting in few side effects is described.

Assisted eruption of impacted teeth into an alveolar bone graft in a patient with cleft lip and palate

Abstract Aims To assist the eruption of impacted upper teeth into an alveolar bone graft in a patient with a unilateral cleft lip and palate. Methods An 8 year-old Thai boy with left unilateral complete cleft lip and palate had the chief complaint of anterior crossbite. He presented with a mild skeletal 3, dental Class III subdivision malocclusion, anterior crossbite, left unilateral posterior crossbite, moderate crowding in the upper arch with impaction of upper the left lateral incisor (tooth 22) and canine (tooth 23). In the first phase of treatment the posterior crossbite was corrected with a removable appliance with a 3-way screw. In the second phase the impacted teeth were surgically exposed, moved into the alveolar bone graft and the teeth aligned with fixed appliances. The upper left lateral incisor was extracted because of its questionable longevity. Results The orthodontic treatment resulted in normal overjet, overbite and an acceptable facial profile. A prosthesis replaced tooth 22. Conclusions Forced eruption of impacted teeth can be carried out successfully in the cleft patients after an appropriate treatment plan has been formulated and following preparation of alveolar bone graft in the cleft site.