Amount Of Crowding Research Articles

Evaluation of the relationship between incisor torque and profile aesthetics in patients having orthodontic extractions compared to non-extractions

ObjectiveThe aim of the present study was to evaluate the relationship between soft tissues aesthetics and incisor torque, as well as the effect of crowding, anchorage, and extraction pattern, in adult patients treated without extraction or with two or four extractions.Materials and methodsSeventy-seven subjects with permanent dentition were selected retrospectively. Among these, 24 patients were treated with four extractions, 24 with two extractions and 29 without extractions. Lateral cephalograms and photographies taken before (T0) and after (T1) treatment were retrieved. The amount of crowding and the type of anchorage were recorded, and a cephalometric analysis was performed. A one-way ANOVA was used to compare the variables within and between groups. Linear regressions were performed to evaluate the effect of different predictors on soft tissues variables at T1.ResultsThe statistical analysis showed no differences within and between groups for soft tissue aesthetics. A significant reduction of the angle obtained from the intersection of Frankfurt plane and mandibular plane was observed in the four-extractions group, and a significant proclination of the lower incisors was observed in the two-extraction group. Linear regressions revealed that the change in soft tissue profile aesthetics was affected by the type of anchorage and the two-extractions pattern.ConclusionsSimilar soft tissue aesthetics were observed after treatment in the three groups, despite the presence of some skeletal and dental differences.Clinical relevanceA well-controlled incisor torque helps to preserve soft tissues aesthetics. The type of anchorage could influence soft tissues.

Factors that may increase the risk of external apical root resorption during orthodontic treatment : Retrospective clinical investigation.

To determine the correlation between external apical root resorption and malocclusion-related variables in patients treated with fixed orthodontic appliances. In all, 103patients aged 12-15years and treated with edge-wise appliances either without extractions or with four premolar extractions were included in this retrospective cohort study. External apical root resorption was assessed in the pre- and posttreatment panoramic radiographs of these patients for incisors, canines, premolars, and first molars. Atotal of 2332 teeth were evaluated in 206 panoramic radiographs obtained from 103patients. The gender of the patients, duration of orthodontic treatments, presence of premolar extractions, Angle classification, overbite, overjet and amount of crowding were assessed. Wilcoxon signed-rank test, Mann-WhitneyUtest, and Kruskal-Wallis test were used for statistical analysis of the data. Statistically significant (p < 0.001) root resorption occurred in all examined teeth during orthodontic treatment. The degree of root resorption observed in the premolars was significantly greater in premolar extraction cases than in nonextraction cases. Statistically significant negative correlations were found between the degree of root resorption of the maxillary lateral teeth and between the maxillary first premolar teeth and the amount of maxillary crowding. The orthodontic treatment protocols and the amount of tooth movements achieved were shown to be dependent on the severity of dental malocclusions and they have an influence on the amount of external apical root resorption that occurs during the course of orthodontic treatment.

Factors influencing the orthodontic treatment plan in Class II malocclusion

This study aimed to investigate the influence of orthodontists' demographics and patient characteristics on the orthodontic treatment plan decision for borderline Class II Division 1 malocclusion in growing patients. An electronic survey was distributed to orthodontists through the American Association of Orthodontists. Participating orthodontists were asked to select their preferred orthodontic treatment plan for 3 patients with borderline Class II Division 1 malocclusion. The survey also included questions about the patient-related factors contributing to the treatment decision for each patient. A total of 113 orthodontists completed the survey. United States-trained orthodontists were more likely to select growth modification and nonextraction relative to extraction (odds ratio, 3.50; 95% confidence interval, 1.01-12.12; odds ratio, 3.59; 95% confidence interval, 1.18-10.91, respectively). Clinicians with>15 years of experience were 72% less likely to prefer nonextraction relative to extraction in 1 patient and were 67% less likely to prefer growth modification relative to extraction in another patient. Working solely in private practice was associated with higher, but not statistically significant, odds of growth modification and nonextraction. The practice location was also associated with treatment plan decisions; however, findings were inconsistent between the patients. The orthodontist's experience, place of education, location, and type of practice appear to influence the preferred treatment plan for Class II malocclusion. Overall, the patient's profile and age were the most considered patient-related factors for growth modification, whereas the patient's profile, amount of crowding, and smile esthetics were the most considered factors for preferring extraction and nonextraction treatment modalities.

Development of a new evaluation method for orthodontic forces generated in individual patients.

Numerous experimental studies have examined how much orthodontic force is needed to move teeth more smoothly; however, no reports have examined this clinically in individual, living subjects. We aimed to develop a method for quantifying the force exerted on individual teeth by an orthodontic wire to measure how loads placed on crowded teeth change dynamically over time. Accordingly, we fabricated a series of dental casts of patients undergoing orthodontic treatment (using optical impressions and a three-dimensional printer), fitted these models with nickel-titanium wire, and subjected them to bending load tests. During leveling, nickel-titanium wire is generally considered to exert a weak force due to its low elastic modulus, with a weak orthodontic force applied over a long period of time due to its superelasticity; however, we found that the actual energy exerted by nickel-titanium wire is also largely affected by other factors (e.g., amount of crowding).

Bacterial composition of subgingival plaque in crowded and noncrowded teeth

Patients with dental crowding, even with good oral hygiene, may show increased bacterial presence in the crowded area. This study aimed to determine the microbial composition of subgingival plaque in crowded and noncrowded dental regions. Forty dental students with anterior dental crowding, who were aware of correct brushing techniques and oral hygiene, were enrolled in this study. After orthodontic records were taken and the periodontal examination was performed, subgingival plaque samples were collected from the crowded (experimental) and noncrowded regions (control) of each patient. Colony counting was performed for Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and streptococcus species. The mean amount of Aa and Pg colonies was significantly higher in crowded areas (P<0.0001), but there was no significant difference between streptococcus species colonization and crowding. Aa and Pg colonization had a significant direct relation with the amount of crowding. (P<0.0001). Crowded dental areas, even with good oral hygiene, are more suitable environments for Aa and Pg colonization.

Treatment Time of Class II Malocclusion, with and without Mandibular Crowding, Treated with Four Premolar Extractions: A Retrospective Study.

This study aimed to compare the treatment times in patients with complete bilateral Class II malocclusion, with and without mandibular crowding, treated with 4 premolar extractions. The sample comprised 57 retrospectively and consecutively selected patients (30 male, 27 female) treated for initial Class II malocclusion, divided as follows: Group 1 consisted of 23 patients (11 males, 12 females; mean age 13.13 years) presenting no crowding or 3 mm at most. Group 2 consisted of 34 patients (19 males, 15 females; mean age13.06 years) presenting more than 4 mm of crowding. Crowding was manually measured in the initial dental casts. The Objective Grading System (OGS) index was manually measured in the final dental casts and radiographic images. The groups were comparable regarding initial age, gender distribution, and final occlusal statuses. The treatment times between the groups were compared using the t-test. Correlation between crowding and treatment time was evaluated with Pearson correlation coefficient. Treatment times between the 2 groups were similar (P = .890) and there was no significant correlation between the amount of crowding and treatment time (r = 0.04, P = .760). Treatment times for complete Class II malocclusion with and without mandibular crowding, treated with 4 premolar extractions, are similar.

Eficácia do pacote Invisalign Lite no tratamento do apinhamento anterior – percepção de ortodontistas e leigos

The aim of the research was to evaluate the efficacy of Invisalign Lite package in mild and moderate anterior crowding treatment from the perspective of orthodontists and lay people. Ten subjects treated with Invisalign Lite were consecutively selected and divided into 2 groups: less than 2mm crowding (mild) and more than from 2mm to 5mm crowding (moderate). Images pre- and post-treatment of each subject were obtained from digital cast and randomly arranged in a Power Point presentation. The evaluation was performed by 109 individuals divided into 2 groups: orthodontists and lay people. They were asked to assign a score for teeth alignment from 1 (poor) to 5 (excellent). Also, the evaluators had to answer for each of the images, if in their opinion orthodontic treatment was necessary. In all groups the Kolmogorov-Smirnov normality test was performed. Paired t-test and non-parametric Wilcoxon test were used for paired comparison. The independent t-test and non-parametric Mann-Whintney were used for comparing evaluators groups and the amount of crowding. In all tests a 5% (p&lt;0,05) significance level was adopted. For the orthodontists, alignment evaluation increased from 2,85 to 4,13 after orthodontic treatment. The scores assigned by lay people increased from 2,54 to 3,69. Orthodontists pointed out that they would indicate orthodontic treatment for 11,15% of the post-treatment images. For lay people, orthodontic treatment would be necessary for 35,63% of post-treatment images.

TREATMENT OF CLASS I MALOCCLUSION WITH MILD CROWDING AND MIDLINE SHIFT

ABSTRACT Background: The main goal of orthodontic treatment is to obtain a normal relationship of the teeth with facial structures and it is generally accepted that orthodontic treatment will have effects on facial proportion. Nowadays, facial appearance has a big influence on someone's appearance. Aesthetic facial appearance will produce a proportional, harmonious, and youthful facial profile. Case: this case report aims to describe that non extraction orthodontic treatment in class I malocclusion with mild crowding and mildline shift is a treatment with considerable success. Case management: A 19 years old female came with a chief complaint of crowding in upper and lower jaw. Intraoral examination revealed bilateral Class I molar and canine relationship. Patient had crowding in upper and lower jaw, and midline shift in lower jaw. Extra oral findings included a flat profile with competent lips. Cephalometric analysis showed skeletal class I with orthognati maxilla and mandible. Patient was bonded with 0.022-inch MBT brackets orthodontic appliance without extraction. After 20 months of treatment, an ideal arch coordination was achieved, the patient felt confident and satisfied with the treatment outcome. Conclusion: Decision to extract a tooth has to be made, not only by considering the amount of crowding, but also the eventual influence of orthodontic tooth displacement on the soft tissue surface of the face. Keywords: Crowding, Midline shift, Non – extraction.

Apiñamiento de dientes anteriores y bullying en escolares.

Objective: To compare the crowding of anterior teeth in schoolchildren with and without experience of bullying. Materials and Methods: A prospective, cross-sectional, comparative and observational study was conducted in two educational institutions, one public and one private; The sample consisted of 218 schoolchildren between 11 and 16 years of age. Dental crowding was evaluated in the upper and lower anterior sector using Little's irregularity index. To diagnose bullying, a previously validated questionnaire was applied, with dichotomized questions. The comparison between crowding in patients with and without experience of bullying was evaluated with the U-Mann Whitney statistical test. Results: Statistically significant differences in the amount of crowding (p&lt;0.05) were found. The average crowding for the group subjected to bullying was 11.6 +/- 9.4 mm and in the group without bullying was 9.1+/- 7.9 mm. Conclusion: There was a higher amount of dental crowding in schoolchildren subjected to bullying compared to schoolchildren with no bullying.

Which factors influence orthodontists in their decision to extract? A questionnaire survey.

BackgroundTo evaluate the relative influence of different criteria in the choice between extraction and nonextraction treatment in current orthodontics, and to assess how the percentage of extractions has evolved over time.Material and MethodsPre-treatment records (panoramic radiograph, lateral cephalogram, study casts and photographs) of fourteen cases in permanent dentition (adult or adolescent) with class I molar relationship and moderate anterior crowding were evaluated by 28 orthodontists. For each case, each orthodontist filled out a questionnaire reporting his treatment plan proposal (extraction or nonextraction) and the importance of specific parameters in his decision-making process, using categorical scales. Orthodontists practicing for more than 15 years were also asked to compare this decision with the one they would have taken at the beginning of their professional career.ResultsThe two most important factors in the decision-making were the soft tissue profile and the amount of crowding. The least important factor was the presence of third molars. In cases of nonextraction treatment, the lack of space was managed mostly by dental expansion and stripping. Twenty percent of the case evaluations revealed extraction(s) decisions. Among the orthodontists practicing for more than 15 years, the current extraction rate reached 24%, whereas the same orthodontists reported they would have extracted in 39% of the cases in the past.ConclusionsThe present study suggests that soft tissue profile has a higher impact than traditional criteria such as cephalometric measurements in the extraction decision. This is associated with a decreased extractions rate compared to the past. Key words:Orthodontics, extractions, survey, treatment planning.

Assessment of Gingival Biotype and Keratinized Gingival Width of Maxillary Anterior Region in Individuals with Different Types of Malocclusion.

The aim of the present study is to evaluate the relationship of gingival thickness and width of keratinized gingiva with different malocclusion groups and amount of crowding. A total of 181 periodontally healthy subjects were enrolled in the present study. The study participants were divided into three malocclusion groups: Angle Class I, Angle Class II, and Angle Class III. Each group was divided into subgroups according to the amount of dental crowding, namely mild, moderate, and severe. The width of keratinized gingiva was calculated as the distance between mucogingival junction and free gingival margin, whereas gingival thickness was determined by a transgingival probing technique. Tooth numbers 13 and 23 were observed to have thin gingival biotype. The width of keratinized gingiva for tooth numbers 13 and 23 was narrower in the severe crowding group than in the moderate and mild crowding groups. The relationship of gingival thickness and width of keratinized gingiva with Angle classification was not found to be significant. Although it is thought that there is a relationship between gingival thickness, width of keratinized gingiva, and Angle classification with regard to malaligned teeth, this cross-sectional evaluation of 181 patients failed to show a significant relationship.

Model Analysis of Digital Models in Moderate to Severe Crowding: In Vivo Validation and Clinical Application.

Objective We investigated the suitability of intraoral-scan models for measuring tooth dimensions and the amount of crowding in patients with severe tooth crowding. Materials and Methods Fifty-eight patients who had undergone intraoral scans for diagnosis were included. Cast models were divided into two groups depending on the amount of crowding, as determined by initial caliper-based measurements (mild crowding [MC] group: <3.0 mm; severe crowding [SC] group: >4.5 mm). Twenty maxillary models and 20 mandibular models were used in this study. For the three types of models (i.e., IS digital model, C cast model, and CS digital model), the reproducibility and the precision of linear measurements were evaluated. Results We found that linear measurements made using digital calipers on a plaster model and on the relevant software were reproducible. There was no significant difference in most linear measurements between digital models and the C model. There were differences in the amount of crowding (p < .05), although these were not clinically significant. There was no relationship between the precision of crowding in the three types of models and the severity of crowding. Conclusions Digital models can be used for measuring crowding in both mild and severe crowding cases. However, crowding measured by digital models tends to be lesser than that measured by cast models, and this should be considered during clinical application.

Correlation between tooth size-arch length discrepancy and interradicular distances measured on CBCT and panoramic radiograph: an evaluation for miniscrew insertion.

Introduction: The selection of appropriate sites for miniscrew insertion is critical for clinical success. Objectives: The aim of the present study was to evaluate how interradicular spaces measured on panoramic radiograph compare with Cone-Beam Computed Tomography (CBCT), and how crowding can influence the presence of available space for miniscrew insertion, in order to define a new “safe zones” map. Methods: A total of 80 pre-treatment panoramic radiographs and 80 CBCT scans with corresponding digital models were selected from the archives of the department of Dentistry, Aarhus University. Crowding was measured on digital models, while interradicular spaces mesial to the second molars were measured on panoramic radiographs and CBCTs. For panoramic radiographs, a magnification factor was calculated using tooth widths measured on digital models. Statistical analyses were performed to investigate the correlation between the amount of crowding and the available interradicular space. Visual maps showing the amount of interradicular spaces measured were drawn. Results: The most convenient interradicular spaces are those between the second molar and the first premolar in the mandible, and between the central incisors in the maxilla. However, some spaces were revealed to be influenced by crowding. Conclusions: Calibration of panoramic radiographs is of utmost importance. Generally, panoramic radiographs underestimate the available space. Preliminary assessment of miniscrew insertion feasibility and the related selection of required radiographs can be facilitated using the new “safe zone” maps presented in this article.

Average interradicular sites for miniscrew insertion: should dental crowding be considered?

ABSTRACTObjective: To define a map of interradicular spaces where miniscrew can be likely placed at a level covered by attached gingiva, and to assess if a correlation between crowding and availability of space exists. Methods: Panoramic radiographs and digital models of 40 patients were selected according to the inclusion criteria. Interradicular spaces were measured on panoramic radiographs, while tooth size-arch length discrepancy was assessed on digital models. Statistical analysis was performed to evaluate if interradicular spaces are influenced by the presence of crowding. Results: In the mandible, the most convenient sites for miniscrew insertion were in the spaces comprised between second molars and first premolars; in the maxilla, between first molars and second premolars as well as between canines and lateral incisors and between the two central incisors. The interradicular spaces between the maxillary canines and lateral incisors, and between mandibular first and second premolars revealed to be influenced by the presence of dental crowding. Conclusions: The average interradicular sites map hereby proposed can be used as a general guide for miniscrew insertion at the very beginning of orthodontic treatment planning. Then, the clinician should consider the amount of crowding: if this is large, the actual interradicular space in some areas might be significantly different from what reported on average. Individualized radiographs for every patient are still recommended.

Linear regression.

Linear regression.

A comparison of second premolar extraction and mini-implant total arch distalization with interproximal stripping

The effect of total arch distalization using orthodontic mini-implants (OMIs) combined with interproximal stripping (IPS) and second premolar extraction was investigated in Class I malocclusion patients. A total of 66 consecutively treated Class I malocclusion (Class I molar relationship; 0 mm < overbite and overjet < 4.5 mm) patients ranging in age from 17 to 44 years who received single-phase treatment were included in this study. Pre- and posttreatment lateral cephalograms and dental casts were measured and compared statistically. In the distalization with IPS group, 3.6 mm and 3.8 mm of crowding in the upper and lower arches, respectively, were resolved, and 3.8 mm and 3.2 mm of upper and lower incisor retraction, respectively, were achieved simultaneously by the treatment. As a result of the second premolar extraction treatment, 3.9 mm and 3.6 mm of crowding in the upper and lower arches, respectively, were resolved, and 3.3 mm and 3.2 mm of incisor retraction, respectively, were achieved during treatment. There was no statistically significant difference in the amount of crowding and incisor retraction between the two groups. Total arch distalization using an OMI with IPS did not yield a significantly different treatment result compared to second premolar extraction treatment.

Mandibular dental arch changes associated with treatment of crowding using self-ligating and conventional brackets

The purpose of this study was to investigate the effect of treatment of mandibular crowding with self-ligating and conventional brackets on dental arch variables. Fifty-six patients were selected from a pool of subjects satisfying the following inclusion criteria: non-extraction treatment in the mandibular or maxillary arches, eruption of all mandibular teeth, no spaces and an irregularity index greater than 2 mm in the mandibular arch, and no adjunct treatment such as etxra- or intraoral appliances. The patients were assigned to two groups: one group received treatment with the self-ligating bracket and the other with a conventional edgewise appliance, both with a 0.022 inch slot. Lateral cephalometric radiographs obtained at the beginning (T1) and end (T2) of treatment were used to assess the alteration in mandibular incisor inclination, and measurements of intercanine and intermolar widths were made on dental casts to investigate changes associated with the correction. The results were analysed with bivariate and multivariate linear regression analysis in order to examine the effect of the bracket systems on arch width or lower incisor inclination, adjusting for the confounding effect of demographic and clinical characteristics. An alignment-induced increase in the proclination of the mandibular incisors was observed for both groups; no difference was identified between self-ligating and conventional brackets with respect to this parameter. Likewise, an increase in intercanine and intermolar widths was noted for both bracket groups; the self-ligating group showed a higher intermolar width increase than the conventional group, whereas the amount of crowding and Angle classification were not significant predictors of post-treatment intermolar width.

Long-Term Visual Function and Relative Amblyopia in Posterior Persistent Hyperplastic Primary Vitreous (PHPV)

Background: Favorable results in the management of PHPV, made possible by improved surgical techniques, are described in the literature. However, the functional results are in general in the low-vision sector (rarely better than 0.025–0.1 maximum). Purpose: To introduce long-term acuity results and estimate the relative amblyopia in early operated PHPV. Material and Methods: Six patients suffering from PHPV of varying degrees (posterior polar cataract, posterior lenticonus, traction and malformation of the optic nerve head and macula region, persistent vitreous vessels) underwent pleoptic treatment after surgery (lentectomy in all, additional stalk-cutting in three cases) at the age of 3 to 7 months. The patients were followed up to age 7 to 12 years. Visual acuity was assessed by Landolt ring single and closely interspaced linear optotypes (C-Test developed by Haase/Hohmann). Results: Compliance with the amblyopia treatment was good in five patients. Visual acuity (VA) improvement in the affected eye could be seen up to early school age (6–8 years). Final VA outcome was 0.1 (minimum) to 0.7 (maximum) with single optotypes. VA for crowded optotypes was maximum 1 octave below single optotype VA. The visual development of the phakic eye was not delayed, i.e. not disturbed by long-term patching. Discussion: Compliance with amblyopia treatment and long-term visual acuity in the cases presented here are even more favorable than described in the literature. As the amount of crowding is small, we conclude that there is little relative (additional) amblyopia and that the functional outcome is limited only by the degree of ocular malformation. Surgical treatment in comparable cases is encouraged.

No correlation between primary mandibular anterior crowding and vertical craniofacial configuration or lower incisor inclination.

The aim of the present study was to evaluate the correlation between primary mandibular anterior crowding and vertical craniofacial configuration or sagittal lower incisor inclination. The collective comprised 100 consecutive patients (50 males, 50 females) subject to 4 selection criteria: mandibular anterior crowding > or = 1.0 mm, no previous orthodontic therapy, completely preserved deciduous canines and molars, and lateral cephalograms of good diagnostic quality before initiation of orthodontic treatment. Study casts of all patients were used to measure the mesiodistal width of the incisors and deciduous canines as well as the anterior arch circumference. The difference between the 2 represented the amount of crowding. On all cephalograms 16 parameters of vertical craniofacial configuration and 9 parameters of lower incisor inclination were measured. For error evaluation all measurements were repeated independently on 10 randomly selected study casts and cephalograms. This error amounted for the combined tooth width to 0.51% +/- 0.81, for arch circumference to 0.03% +/- 0.68, and for all cephalometric parameters to 0.38% +/- 4.81. For all parameters, arithmetic means, standard deviations and ranges were calculated. Further, correlation coefficients were calculated between anterior crowding and all 25 cephalometric parameters. The arithmetic mean of crowding was m = 2.0 +/- 1.3 mm with a range of 1.0 to 6.6 mm. The values of all cephalometric parameters were close to well accepted norms in the literature. The correlation coefficients between crowding and all cephalometric parameters varied from r = 0.0 to 0.3. According to this study there is no correlation between primary mandibular anterior crowding and vertical craniofacial configuration or sagittal lower incisor inclination.

CODLING MOTH POPULATIONS UNDER NATURAL, INTEGRATED, AND CHEMICAL CONTROL ON APPLE IN NOVA SCOTIA (LEPIDOPTERA: OLETHREUTIDAE)

AbstractCodling moth populations on natural apple fruit trees scattered throughout Nova Scotia are compared with those in commercial orchards. In natural fruit, failure of crop, crop size, degree of isolation, amount of crowding by native trees, and natural enemies determine the level of codling moth numbers. Young commercial orchards require artificial control measures within a few years of first bearing fruit to prevent severe crop losses. In older commercial orchards natural controls require an occasional assist by chemical treatment to contain the codling moth below economically tolerable levels. Such treatment is applied to interfere as little as possible with known natural controls.