Accurate malocclusion tooth segmentation method based on a level set with adaptive edge feature enhancement.

Objective: This study aimed to accurately segment teeth under complex oral conditions, including complex structural interference among adjacent teeth or malocclusion conditions, such as tooth rotation and displacement caused by dental crowding. Study design: Cone-beam computed tomography (CBCT) images were obtained from 19 patients with complex oral conditions, and a three-step solution was proposed. This study used a global convex level-set model to extract bony tissue and developed a flexible curve extraction method for separating neighbouring teeth under complex structural interference. In addition, a local level-set model with adaptive edge feature enhancement was proposed to segment individual teeth precisely. This model adaptively enhances edge features based on the structure of the root boundary and accurately distinguishes between the close-contact root and alveolar bone resulting from tooth rotation or displacement. Results: The experimental results showed that the average Dice similarity coefficient values for incisors, canines, premolars, and molars were 93.30%, 93.47%, 93.24%, and 93.89%, respectively, and the average tooth centroid distances were 0.66, 0.61, 0.87, and 0.80 mm, respectively. Conclusion: The proposed method can effectively segment teeth without relying on highly precise annotated datasets, yielding satisfactory results even under complex structural interference between adjacent teeth or tooth rotation and displacement caused by dental crowding. It is more robust than the other methods and provides valuable data for further research and clinical practice.

Assessing the morphological characteristics of teeth and dental arches as potential predictors of dental crowding.

Background and aims: The early detection of dental crowding and its potential for aggravation is important during the clinical examination of mixed dentition patients, and these desiderates can be addressed by including among the clinically assessed items a series of accessible morphological characteristics of teeth and dental arches. The present study investigates possible correlations between morphological features of permanent teeth, widths of dental arches, and the onset of dental crowding during mixed dentition. Methods: A selected group of 100 class I dental casts on mixed dentition was analyzed. The dental arches were grouped as spaced, normally aligned, and crowded. The dental parameters consisted of mesiodistal dimensions of permanent teeth and specific morphological features of permanent incisors and first molars. The anterior and posterior arch widths according to Pont indices were measured. Results: Statistical analysis of data showed that mesiodistal dimensions of the permanent upper central incisors and lower incisors are significantly larger on severely crowded arches than on normally aligned arches; increased differences between mesiodistal dimensions of central and lateral permanent upper incisors and the presence of semi-shavel incisors and Carabelli cusps are associated with a greater extent of anterior crowding. The severely crowded arches presented significantly narrower anterior and posterior arch widths. Conclusions: Increased mesiodistal dimensions of permanent incisors, the presence of incisors shoveling, the Carabelli cusps on upper first permanent molars, and narrowing of dental arches during the early mixed dentition period were associated with severe dental crowding in class I cases.

Association between Eruption Sequence of Posterior Teeth, Dental Crowding, Arch Dimensions, Incisor Inclination, and Skeletal Growth Pattern.

BACKGROUND: We conducted research to investigate the effects of the eruption sequence of posterior teeth, arch dimensions, and incisor inclination on dental crowding. MATERIAL AND METHODS: A cross-sectional analytic study was performed on 100 patients (54 boys and 46 girls; mean ages: 11.69 and 11.16 years, respectively). Seq1 (canine-3-/second premolar-5-) or Seq2 (5/3) eruption sequences were recorded in maxilla, and Seq3 (canine-3-/first premolar-4-) or Seq4 (4/3) eruption sequences in mandible; tooth size, available space, tooth size-arch length discrepancy (TS-ALD), arch lengths, incisor inclination and distance, and skeletal relationship were noted. RESULTS: The most common eruption sequences in the maxilla and mandible were Seq1 (50.6%), and Seq3 (52.1%), respectively. In the maxilla, posterior tooth sizes were larger in crowded cases. In the mandible, anterior and posterior tooth sizes were larger in crowded patients. No relationship between incisor variables and the maxillo-mandibular relationship and dental crowding was found. A negative correlation between inferior TS-ALD and the mandibular plane was found. CONCLUSIONS: Seq1 and Seq 2 in the maxilla and Seq 3 and Seq 4 in the mandible were equally prevalent. An eruption sequence of 3-5 in the maxilla and 3-4 in the mandible is more likely to cause crowding.

Accuracy and eligibility of Bonwill⁃Hawley arch form established by CBCT image for dental crowding measurement: a comparative study with the conventional brass wire and caliper methods.

OBJECTIVES: The purpose of this study was to develop a novel Bonwill⁃Hawley method (Bonwill⁃Hawley arch form based on CBCT image) for the assessment of dental crowding, and to investigate and compare the accuracy and eligibility with the conventional brass wire and caliper methods under different crowding conditions. MATERIAL AND METHODS: Sixty patients with the pair of plaster casts and CBCT data were collected. All the casts were marked and transformed into digital models using iTero scanner, and imported into OrthoCAD software to measure the required space. Using the conventional brass wire (M1) and caliper methods (M2), the available space and dental crowding were measured and calculated basing on digital models, respectively. Correspondingly, the axial planes in the level of dental arches were oriented and captured from the CBCT images to draw the Bonwill⁃Hawley arch forms (M3), which were used to measure and calculate the available space and dental crowding. For each method, intra and inter-examiner reliabilities were evaluated with intra-class correlation coefficients (ICCs). Wilcoxon test and Kruskal-Wallis test were performed for statistically analyzing the discrepancy among different groups. RESULTS: Both intra- and inter-examiner reliability were generally excellent for all parameters obtained by the three methods, except for the dental crowding measured using M1(ICC: 0.473/0.261). The dental crowding measured using M2 were significantly increased in mild, moderate and severe-crowding groups compared with M1. However, no significant difference was detected between M1 and M3 in severe-crowding group (maxilla, p = 0.108 > 0.05; mandible, p = 0.074 > 0.05). With the deterioration of crowding condition, the discrepancy of dental crowding between M1 and M2, or M1 and M3 were significantly decreased (maxilla, M2-M1, mild VS serve, p = 0.003 < 0.05; maxilla, M3-M1, mild VS serve, p = 0.003 < 0.05; mandible, M2-M1, mild VS serve, p = 0.000 < 0.001; mandible, M3-M1, mild VS serve, p = 0.043 < 0.05). CONCLUSION: Dental crowding measured using the novel Bonwill⁃Hawley method was relatively greater than the caliper method, but not exceeding the brass wire method, which wound gradually come close to the brass wire method with the deterioration of crowding condition. CLINICAL RELEVANCE: The Bonwill⁃Hawley method basing on CBCT image proved to be a reliable and acceptable choice for orthodontists to analyze the dental crowding.

An Anthropological Investigation of the Sociocultural and Economic Forces Shaping Dental Crowding Prevalence.

OBJECTIVE: The aim of the current study is to explore country of origin and social race category differences in dental crowding prevalence through an anthropological approach. DESIGN: Data were collected from individuals within five countries (Australia, China, Japan, South Africa, United States; n = 1008) and seven social race groups in two countries (American Black, American White, Latinx, and Indigenous in the United States, South African Black, South African White, and South African Coloured; n = 654). Statistical significance between groups was assessed with a Kruskal-Wallis test, while a Dunn's post-hoc test identified which groups significantly differed. RESULTS: Results indicate South Africa is characterized by the lowest frequencies of dental crowding, with Coloured South Africans yielding the highest and Black South Africans displaying the lowest frequencies. Individuals in the United States exhibited relatively high levels of minor dental crowding. American Blacks had lower crowding levels, while the Indigenous group had high levels of severe crowding. Individuals within China and Japan exhibited higher relative prevalence of severe crowding. CONCLUSIONS: Overall, significant differences exist in dental crowding prevalence across countries and social race categories using an anthropological grading system to assess crowding. These differences are likely impacted by sociocultural (aesthetic preferences) and economic (access to dental care) factors.

Skeletal and dental age discrepancy and occlusal traits in children with growth hormone deficiency and idiopathic short stature.

OBJECTIVES: The aim of the study was to evaluate the dental and bone age delay and occlusal traits of children with growth hormone deficiency (GHD) and idiopathic short stature (ISS). MATERIAL AND METHODS: The study group included 46 patients aged 5 to 14 years: 15 with ISS, 17 with GHD before growth hormone treatment, and 14 with GHD during substitution therapy. The control group consisted of 46 age and sex-matched subjects of normal height. A calibrated dentist assessed all subjects in terms of dental age and occlusal characteristics. Bone age was evaluated only in GHD and ISS children as a part of a hospital's diagnostic protocol. RESULTS: The subgroup of GHD before treatment differed significantly concerning dental age delay from their healthy peers (- 0.34 and 0.83 year, respectively, p = 0.039). Dental age delay in short stature children was less marked than bone age delay (- 0.12 and - 1.76, respectively, p < 0.00001). Dental crowding was recorded in 57% of ISS patients and 53% of GHD children before treatment compared to only 22% of the control subjects (p = 0.027 and p = 0.021, respectively). CONCLUSIONS: Dental age was retarded in GHD children before growth hormone (GH) therapy, but the delay does not seem clinically significant. ISS children and GHD children before therapy showed marked bone age delay and tendency to crowding. CLINICAL RELEVANCE: The different pace of teeth eruption and skeletal growth in short stature children should be considered when planning their dental treatment.

Enamel interproximal reduction during treatment with clear aligners: digital planning versus OrthoCAD analysis.

BACKGROUND: The aim of the study was to compare the amount of interproximal enamel reduction (IPR) provided on ClinCheck software with the amount of IPR carried out by the orthodontist during treatment with clear aligners. METHODS: 30 subjects (14 males, 16 females; mean age of 24.53 ± 13.41 years) randomly recruited from the Invisalign account of the Department of Orthodontics at the University of Rome "Tor Vergata" from November 2018 to October 2019, were collected according to the following inclusion criteria: mild to moderate dento-alveolar discrepancy (1.5-6.5 mm); Class I canine and molar relationship; full permanent dentition (excluding third molars); both arches treated only using Comprehensive Package by Invisalign system; treatment plan including IPR. Pre- (T0) and post-treatment (T1) digital models (.stl files), created from an iTero scan, were collected from all selected patients. The OrthoCAD digital software was used to measure tooth mesiodistal width in upper and lower arches before (T0) and at the end of treatment (T1) before any refinement. The widest mesio-distal diameter was measured for each tooth excluding molars by "Diagnostic" OrthoCAD tool. The total amount of IPR performed during treatment was obtained comparing the sum of mesio-distal widths of all measured teeth at T0 and T1. Significant T1-T0 differences were tested with dependent sample t-test (P < 0.05). RESULTS: In the upper arch, IPR was digitally planned on average for 0.62 mm while in the lower arch was on average for 1.92 mm. As for the amount of enamel actually removed after IPR performing, it was on average 0.62 mm in the maxillary arch. In the mandibular arch, the mean of IPR carried out was 1.93 mm. The difference between planned IPR and performed IPR is described: this difference was on average 0.00 mm in the upper arch and 0.01 in the lower arch. CONCLUSIONS: The amount of enamel removed in vivo corresponded with the amount of IPR planned by the Orthodontist using ClinCheck software.

Comparison of Tooth Widths, Arch Widths and Arch Lengths in Class-I Normal Dentition to Class-I and II Crowded Dentitions.

BACKGROUND AND OBJECTIVE: Dental study casts play a vital role in the diagnosis and treatment planning of various orthodontic cases. This study was carried out to compare the tooth widths, arch widths, and arch lengths in Class-I normal dentition to those in Class-I and Class-II crowded dentition in an effort to improve treatment planning and to eventually reduce treatment duration. METHODS: Total 170 patients, 12 to 40 years of age with a complete set of permanent teeth till 1st molars; who presented to the Orthodontics Department at Armed Forces Institute of Dentistry (A.F.I.D), Rawalpindi from Sep 2019 to Feb 2020, were included in the study. Non-probability purposive method of sampling was used. The dental casts obtained were used to measure tooth widths, arch widths, and arch lengths. Subjects were classified into Class-I normal and Class-I and Class-II crowded occlusion and comparison of the sum of tooth widths, arch widths, and arch length discrepancies were determined among the three occlusion groups. Data was analyzed in SPSS version 21 and independent samples t-test was used to differentiate the variables of interest. RESULTS: Out of 170 subjects, 73 (42.9%) subjects had Class-I normal occlusion while 97 (57%) had Class-I and Class-II crowded occlusions. No statistical difference was found between the occlusal groups with regard to the sum of tooth widths, inter-canine widths, inter-first premolar widths, inter-second premolar widths and inter-molar widths. However, a remarkable difference was observed between the occlusal groups with respect to arch perimeters and arch length discrepancies (p = 0.000 and 0.000 respectively). CONCLUSIONS: Results of the current study indicate that crowding of teeth occurs as a consequence of decreased arch perimeters which may lead to increased arch length discrepancies. However, no prominent difference was noticed in the sum of tooth widths and arch widths among different occlusal groups.

Skeletal, dental and facial aesthetic changes following anterior maxillary segmental distraction by tooth-borne device in patients with cleft lip and palate.

Maxillary skeletal deficiency secondary to cleft lip and palate (CLP) remains a significant challenge. The aim of this study was to present the comprehensive skeletal, dental and facial aesthetic outcomes of anterior maxillary segmental distraction osteogenesis (AMSDO) for treatment of maxillary hypoplasia in patients with CLP. Twelve patients with maxillary hypoplasia treated with AMSDO by a customized tooth-borne distractor were included. Three-dimensional changes of anterior maxillary segment, upper incisor and pharyngeal space were measured by three-dimensional reconstruction derived from cone beam computed tomography (CBCT) data. Length and width of dental arch during distraction were determined in dental casts. Nasolabial angle, soft-tissue convexity and patient's subjective satisfaction were assessed to evaluate facial aesthetic improvements. Nasopharyngoscopic evaluation and speech assessment were also performed before and after distraction. All patients successfully received AMSDO without serious complications. Following AMSDO, the anterior maxillary segments moved forward 5.56±0.28mm and slightly upward 1.15±0.13mm. AMSDO significantly lengthened maxillary dental arch, generated new bone to relieve dental crowding and improved patients' facial aesthetic without worsening velopharyngeal closure and speech quality. AMSDO by tooth-borne distractor is an effective surgical alternative for the advancement in patients with cleft maxillary hypoplasia.

Quantitative analysis of gingival phenotype in different types of malocclusion in the anterior esthetic zone.

BACKGROUND: For any esthetic treatment planning, the shape and form of gingiva should be a prime factor of concern. The correct identification of gingival phenotype (GP) ensures a firm foundation for future health and prognosis of the treatment indicated. Hence, the aim of the present study was to evaluate the correlation between the GP in the anterior esthetic zone with different types of maloclussion and severity of crowding. MATERIALS AND METHODS: A total of 110 periodontally healthy controls were equally divided into two groups depending on the type of malocclusion. They were further divided according to the levels of dental crowding as mild, moderate, and severe. GP was measured on the anterior esthetic teeth using transgingival probing, and width of the attached gingiva (WAG) was measured using histochemical staining method. RESULTS: In severe crowding group, the GP in 12 and 22 region was found to be thick (P = 0.035) while, in 32 and 42 region was thin (P = 0.042). The WAG shows a significant difference between WAG with 23 in severe crowding group with P = 0.042, whereas there was no significant relationship found between the GP with Angle's classification. CONCLUSION: Within the limitations of the study, it can be concluded that the teeth in the maxillary and mandibular anterior esthetic region showed the thin phenotype. When the severity of crowding increases, the GP and WAG vary depending on the position of the tooth. There is no association between the Angle's classification and the mean GP of the maxillary and mandibular anterior region teeth.

Evaluation of the influence of mandibular third molars on mandibular anterior crowding relapse.

Objective: To evaluate the influence of mandibular third molars on relapse of mandibular anterior crowding in orthodontically treated patients.Material and Methods: Sample included orthodontic records of 108 patients: Group 1: 72 patients (39 female; 33 male) with third molars present in the postretention evaluation stage. Group 2: 36 patients (18 female; 18 male) who did not present the third molars in the postretention evaluation stage. Panoramic radiographs and dental models were evaluated at three different stages: pre-treatment; posttreatment and postretention. Panoramic radiographs showed the presence or absence of third molars in the 3 evaluated stages and on the dental models, overbite and mandibular anterior crowding was measured by the Little Irregularity Index. For intergroup comparisons, t-tests and a multifactorial regression analysis were used.Results: There was no statistically significant difference in the relapse of mandibular anterior crowding among the groups with and without mandibular third molars at the postretention stage.Conclusion: The presence or absence of mandibular third molars did not influence the relapse of mandibular anterior crowding in orthodontically treated patients.

Effects of mini-implant facilitated micro-osteoperforations in alleviating mandibular anterior crowding: A randomized controlled clinical trial.

OBJECTIVES: To investigate the effectiveness of mini-implant (MI)-facilitated micro-osteoperforations (MOPs) in accelerating mandibular anterior teeth alignment. MATERIALS AND METHODS: Thirty teenage patients with mandibular crowding (Little's irregularity index between 4 and 6 mm) were randomly allocated to either "experimental" group (micro-osteoperforation assisted alignment) or "control" group (conventional orthodontics). Blinding was done at the data analysis stages. Six MOPs were performed using MI on the labial aspect in the mandibular anterior region. The primary outcome was the overall treatment time needed to complete alignment of mandibular anterior teeth. The secondary outcomes were to compare the marginal bone height loss and volumetric root resorption around mandibular incisors along with subject's perception of pain, comfort and satisfaction. RESULTS: There was statistically significant difference in the total treatment duration for complete alignment of mandibular incisors. The completion of cases in experimental group was 43.93% times faster than the control group. There were no statistically significant differences in volumetric root resorption and marginal alveolar bone height loss around mandibular incisors as well as pain perception between the two groups. CONCLUSIONS: MI-facilitated MOPs accelerated tooth movement significantly upto nine weeks without any significant pain and discomfort, with no increase in root resorption and marginal alveolar bone height loss.

Prevalencia de apiñamiento dental en la población costarricense que consulta los servicios de odontología de la CCSS, 2017 / Prevalence of dental crowding in the costarican population consulting the dental services of the CCSS, 2017

Resumen El objetivo del presente estudio es determinar la prevalencia del apiñamiento dental determinando el comportamiento y la prevalencia de esta anomalía en el ciclo de vida de las personas y el grupo dentario más afectado en la población que consulta los servicios de odontología de la CCSS. Se realizó un estudio descriptivo del 1 de enero al 30 de abril del 2017 en las áreas de salud del país donde se valoró la cantidad de pacientes sugeridos; para el examen clínico se usó como soporte la ficha de encuesta para la evaluación del estado de salud bucodental, elaborada con variables con base en las necesidades de esta investigación. Se recolecta una muestra de 104.691 datos de personas, en el que el muestreo estratificado por grupos de edad prefijados, es el siguiente: 9.652 niños de 0 a 5 años; 4.270 niños de 6 años; 10.477 niños de 7 a 9 años; 9.495 adolescentes de 10 a 12 años; 13.096 jóvenes de 13 a 19 años; 14.532 mujeres de 20 a 35 años; 7.586 mujeres de 36 a 45 años; 13.435 adultos de 20 a 45 años; 13.504 adultos de 46 a 59 años y 8.644 adultos mayores de 60 y más años, y esta información es procedente de las áreas de salud de las diferentes regiones del país. La prevalencia nacional del apiñamiento dental se estimó en 10% (0,0981 - 0,1018) IC95%, y la prevalencia de apiñamiento dental es menor del 1% en el grupo de 0-5 años, y empieza un aumento acelerado hasta 17% a la edad de 13-19 años, para luego disminuir hasta el 3% en el adulto mayor; que disminuye a partir del grupo de los 13 a 19, debido a que en estas edades comienza a incrementarse la pérdida de piezas dentales producto de la caries dental en que la prevalencia de pieza perdida dental de 5% en el grupo de 13 a 19 se incrementa hasta llegar al 75% en el adulto mayor y la pérdida de dientes por enfermedad periodontal de 0,08 en los adolescentes de 13 a 19 años para luego incrementarse paulatinamente hasta llegar al 18% en el adulto y luego aumentar abruptamente al 39% en el adulto mayor. El apiñamiento promueve dificultades para comer, hablar e incluso problemas bucodentales como consecuencia de la acumulación de placa, caries, enfermedad periodontal, disfunción de la articulación temporomandibular (ATM), además de repercutir en la estética del paciente, disminuyendo su autoestima, por lo que, realizar este tipo de investigaciones nos ayuda a conocer el impacto que tienen este tipo de patologías en la población y que por ser un problema de salud pública, es de especial interés para los tomadores de decisiones en salud, conocer a fondo dicha problemática.

Abstract The aim of this study is to estimate the prevalence of dental crowding, determining its behavior and presence of this anomaly through life, also the most affected population group that uses the dentistry services of CCSS. A descriptive study was made from January 1st through April 30, 2017, in different Costa Rican health services, the number of necessary patients was calculated; for the clinical exam a dental survey record chart was used to evaluate oral health conditions, this chart was specifically designed for the needs of this investigation A sample of 104.691 patients was documented, in which stratified sampling of previously selected age groups was designated as follows: 9.652 children from 0 to 5 years old; 4.270 children under 6 years, 10.477 children from 7 to 9 years old; 9.495 teenagers from 10 to 12 years old; 13.096 teenagers from 13 to 19 years of age; 14.532 women from 20 to 35 years old; 7.586 women from 36 to 45 years old; 13.435 adults from 20 to 45 years of age; 13.504 adults from 46 to 59 years old and 8.644 adults at age 60 or older, and this information proceeded from different regions of the country. The Crowding National Prevalence was estimated at 10% (0.0981 - 0.1018) IC95%, in the group from 0 to 5 years old crowding was lower than 1%, and started increasing quickly up to 17% at 13-19 years of age, after that it lowered down to 3% in the elderly group; crowding decreased in group 13 to 19 years old, possibly because at these ages tooth loss starts increasing due to dental cavities. Tooth loss at ages 13 to 19 had a prevalence of 5% and increased up to 75% in the elderly group. Tooth loss caused by periodontal disease in the age group 13 to 19 had a prevalence of 0.08 and gradually increased to 18% in adults and 39% in the elderly group. Crowding promotes difficulties for eating, speaking, increases oral problems as a consequence of biofilmbaccumulation, dental cavities, periodontal disease, TMD, as well as affecting the patient's esthetics lowering self-esteem, for these reasons this type of investigations helps to understand the impact of this pathology over the population, and since it is viewed as a public health issue, it is of special interest in the health program's decisión making process to comprehend such problematic.

Mandibular symphyseal distraction osteogenesis: 20 years of experience treating transverse deficiencies with an internal hybrid device.

INTRODUCTION: Transverse mandibular deficiency has been traditionally managed by orthodontic compensation. However, without resolving the underlying skeletal hypoplasia it leads to high relapse rates. Few studies have reviewed the long-term experience and potential complications of mandibular symphyseal distraction osteogenesis (MSDO) as an alternative treatment method. MATERIALS AND METHOD: A retrospective review of 20 patients (range: 4-19 years; mean: 11.9 years) treated with a hybrid MSDO device over the period of 1996-2017 was conducted. Epidemiological data, medical and dental history as well as photographic and cephalometric analyses were carried out. Furthermore, pre-operative and long-term post-operative status including dental occlusion and tooth-jaw discrepancies were recorded. RESULTS: The distraction amount ranged from 3 mm to 15 mm (mean: 10 mm) with an average distraction period of 30.9 days. In long-term follow-up (mean: 7.3 years), 14 patients presented a class I and 6 patients presented a class II relationship. Correction of overjet, tooth jaw discrepancy and arch length discrepancy were obtained in 18, 20 and 17 cases respectively. A device malfunction was experienced in 6 patients. CONCLUSION: Mandibular widening using a hybrid MSDO device can be efficiently and safely performed in a paediatric population. Further studies confirming our results and analysing facial aesthetic outcomes are warranted.

Relación entre apiñamiento dentario y terceros molares / Relationship between anterior crowding and third molars

RESUMEN: Introducción: La relación entre terceros molares y el desarrollo o reincidencia de maloclusión y apiñamiento dental tras el tratamiento de ortodoncia, especialmente en el segmento anterior del arco dental, es un tema que ha sido discutido y presentado en la literatura, el cual aún permanece sin resolver. Métodos: Para responder esta pregunta utilizamos Epistemonikos, la mayor base de datos de revisiones sistemáticas en salud, la cual es mantenida mediante búsquedas en múltiples fuentes de información, incluyendo MEDLINE, EMBASE, Cochrane, entre otras. Extrajimos los datos desde las revisiones identificadas, reanalizamos los datos de los estudios primarios, preparamos tablas de resumen de los resultados utilizando el método GRADE. Resultados: Identificamos 7 revisiones sistemáticas que en conjunto incluyen 31 estudios primarios, de los cuales, 2 son ensayos aleatorizados. Conclusiones: El limitado desarrollo de estudios que relacionan los terceros molares con apiñamiento dental y el bajo nivel de evidencia de éstos no permiten tener claridad respecto a la posible asociación. Son necesarios nuevos estudios sobre el tema.

ABSTRACT: Introduction: The relationship between third molars and the development or recurrence of malocclusion and dental crowding after orthodontic treatment, especially in the anterior segment of the dental arch, is a subject that has been discussed and presented in the literature, which still remains unsolved. Methods: To answer this question we used Epistemonikos, the largest database of systematic health reviews, which combines searches in multiple sources of information, including MEDLINE, EMBASE, Cochrane, among others. We extracted the data from the identified reviews, reanalyzed them from the primary studies and prepared summary tables of the results using the GRADE method. Results: We identified 7 systematic reviews that together included 31 primary studies, 2 of which were randomized trials. Conclusion: The limited development of studies that relate third molars to dental crowding and their low level of evidence does not allow us to be certain about the possible association. New studies are necessary.

Adjustable selective maxillary expansion combined with one-stage maxillomandibular surgery: A prospective study of osseous widening in fifty-five consecutive patients.

OBJECTIVE: SARME is often considered to be the only available treatment for significant or severe maxillary transverse palatal deficiencies (MTD) in skeletally-mature patients. Despite this observation, the aim of our study was to assess a new type of maxilla distraction osteogenesis. Using two innovative tools, we performed selective expansion: the site to be widened and the amount of increase were both pre-selected. Patients were treated in a single maxillomandibular procedure. Our study focuses primarily on the extent of osseous widening. STUDY DESIGN: Post-expansion computed tomography data from 55 non-syndromic patients were included in a prospective study and analyzed in two planes for transverse skeletal widening. Of the 55 patients, 16 underwent isolated posterior distraction for severe posterior endognathia (group I), and 39 were treated in both segments (group II). Diastemas and anterior spaces permitted resolution of crowding and patients with a small, narrow, tapering arch were given a more rounded form. All patients underwent a complete Le Fort I with down fracture. Two novel devices were used: first, an adjustable distractor to achieve an angular opening; and secondly, in group II, new modular plates interlocked for osteosynthesis to provide stability and anterior expansion. RESULTS: In group I, analysis of the width of the gain showed significant posterior values decreasing from back to front, a result never achieved with the SARME procedure. The mean osseous gain at first molars was 7.1 mm. When anterior space was required in group II, it was created as wide as needed (mean 4.2 mm, at canine level) with good preservation of the 1st molar space gain (mean 6.8 mm). CONCLUSION: Total Le Fort I osteotomy associated with two innovative devices provides a new, segmental and adaptable approach for transverse distraction osteogenesis. We demonstrate a good match with the dental enlargement required. All patients were managed in a single orthognathic procedure for all the anomalies to be treated. Long-term results show good stability.

Analysis of electromyographic indexes of temporal and masticatory muscles in patients with distal occlusion complicated by dental crowding.

OBJECTIVE: Introduction: Rate of distal occlusion (up to 40%) and dental crowding (up to 65%) is the largest in the structure of orthodontic pathology. The aim of the study was to investigate bioelectrical activity of temporal and masticatory muscles and to set parameters of electromyographic indexes in patients with distal occlusion and dental crowding in permanent occlusion. PATIENTS AND METHODS: Materials and methods: Bioelectrical activity of temporal and masticatory muscles in 11 patients aged 16-24 years was determined before orthodontic treatment. Distal occlusion complicated by severe degree of dental crowding was revealed in this group of patients. These patients comprised the treatment group. The control group consisted of 10 subjects (mean age 21,3 ± 1,25 years) with physiological occlusion. RESULTS: Results: It was found that functional state of temporal and masticatory muscles in patients with distal occlusion complicated by dental crowding changes during permanent dentition. It was determined that in clenching state, according to ACTIV index, temporal muscles are more active, due to the lack of activity of masticatory muscles (ACTIV =-20,73% ± 8,01%). Moreover it is worthy of notice, that functional muscle symmetry (index SIM TА/MМ) at rest in presence of distal occlusion is lower than in subjects with physiological occlusion (p <0,05). CONCLUSION: Conclusions: According to index АCTIV TА/MМ it was established the dominance of temporal muscle activity due to lack of activity of masticatory muscles in patients with distal occlusion complicated by dental crowding and it was determined lower overall muscle symmetry index than in individuals with physiological occlusion.

Mandibular anterior crowding: normal or pathological?

ABSTRACT The teeth become very close to each other when they are crowded, but their structures remain individualized and, in this situation, the role of the epithelial rests of Malassez is fundamental to release the EGF. The concept of tensegrity is fundamental to understand the responses of tissues submitted to forces in body movements, including teeth and their stability in this process. The factors of tooth position stability in the arch - or dental tensegrity - should be considered when one plans and perform an orthodontic treatment. The direct causes of the mandibular anterior crowding are decisive to decide about the correct retainer indication: Should they be applied and indicated throughout life? Should they really be permanently used for lifetime? These aspects of the mandibular anterior crowding and their implication at the orthodontic practice will be discussed here to induct reflections and insights for new researches, as well as advances in knowledge and technology on this subject.

RESUMO Os dentes ficam muito próximos quando estão apinhados, mas suas estruturas permanecem individualizadas e, nessa situação, o papel dos restos epiteliais de Malassez é fundamental para liberar o EGF. A tensigridade é um conceito chave para compreender as respostas dos tecidos submetidos às forças nos movimentos corporais, incluindo os dentes e sua estabilidade nesse processo. Os fatores da estabilidade de posição de um dente na arcada dentária — ou tensigridade dentária — devem ser considerados quando se planeja e finaliza um caso na prática clínica ortodôntica. As causas diretas do apinhamento dentário anteroinferior são determinantes para se refletir se a contenção deve ser mesmo indicada e aplicada por toda a vida e se, necessariamente, deve ser usada de forma permanente. Esses aspectos do apinhamento dentário anteroinferior e suas implicações na prática clínica serão aqui abordados para induzir reflexões e insights de novas pesquisas, bem como avanços no conhecimento e tecnologia sobre esse assunto.

Functional validation reveals the novel missense V419L variant in TGFBR2 associated with Loeys-Dietz syndrome (LDS) impairs canonical TGF-ß signaling.

TGF-ß-related heritable connective tissue disorders are characterized by a similar pattern of cardiovascular defects, including aortic root dilatation, mitral valve prolapse, vascular aneurysms, and vascular dissections and exhibit incomplete penetrance and variable expressivity. Because of the phenotypic overlap of these disorders, panel-based genetic testing is frequently used to confirm the clinical findings. Unfortunately in many cases, variants of uncertain significance (VUSs) obscure the genetic diagnosis until more information becomes available. Here, we describe and characterize the functional impact of a novel VUS in the TGFBR2 kinase domain (c.1255G>T; p.Val419Leu), in a patient with the clinical diagnosis of Marfan syndrome spectrum. We assessed the structural and functional consequence of this VUS using molecular modeling, molecular dynamic simulations, and in vitro cell-based assays. A high-quality homology-based model of TGFBR2 was generated and computational mutagenesis followed by refinement and molecular dynamics simulations were used to assess structural and dynamic changes. Relative to wild type, the V419L induced conformational and dynamic changes that may affect ATP binding, increasing the likelihood of adopting an inactive state, and, we hypothesize, alter canonical signaling. Experimentally, we tested this by measuring the canonical TGF-ß signaling pathway activation at two points; V419L significantly delayed SMAD2 phosphorylation by western blot and significantly decreased TGF-ß-induced gene transcription by reporter assays consistent with known pathogenic variants in this gene. Thus, our results establish that the V419L variant leads to aberrant TGF-ß signaling and confirm the diagnosis of Loeys-Dietz syndrome in this patient.

Low-level laser therapy effectiveness in accelerating orthodontic tooth movement: A randomized controlled clinical trial.

OBJECTIVE: To evaluate the effectiveness of low-level laser therapy (LLLT) in accelerating orthodontic tooth movement of crowded maxillary incisors. MATERIALS AND METHODS: This two-arm, parallel-group, randomized controlled trial involved 26 patients with severe to extreme maxillary incisors irregularity according to Little's irregularity index, indicating two first premolars extraction. Patients were randomly assigned to either the laser group or the control group (13 each). Following premolars extraction, orthodontic treatment with fixed appliances was initiated for both groups. Immediately after insertion of the first archwire, patients in the laser group received a LLL dose from an 830-nm wavelength Ga-Al-As semiconductor laser device with energy of 2 J/point. The laser was applied to each maxillary incisor's root at four points (two buccal, two palatal). Application was repeated on days 3, 7, 14, and then every 15 days starting from the second month until the end of the leveling and alignment stage. Alignment progress was evaluated on the study casts taken before inserting the first archwire (T0), after 1 month of treatment commencement (T1), after 2 months (T2), and at the end of the leveling and alignment stage (T3). The outcome measures were the overall time needed for leveling and alignment and the leveling and alignment improvement percentage. RESULTS: A statistically significant difference was found between the two groups in the overall treatment time (P < .001) and the leveling and alignment improvement percentage at T1 (P = .004) and T2; (P = .001). CONCLUSION: LLLT is an effective method for accelerating orthodontic tooth movement.