Evaluation of the aesthetics and clinical findings in patients with missing maxillary lateral incisors treated with a 10-year interval.

INTRODUCTION: The most common treatment approaches for patients missing maxillary lateral incisors are implant replacement (IT) and orthodontic space closure (SC). Treatment techniques change and improve over time, and it is of interest to know if improvements differ between the methods. AIM: To compare the aesthetic outcome and other clinical findings in patients with one or two missing maxillary lateral incisors who were treated with a 10-year difference in time, with either orthodontic space closure or implant replacement. MATERIAL AND METHODS: A total of 88 patients were included in the study. Forty-four patients treated between 2011 and 2018 were included as the latter cohort (LC). The LC was compared to the early cohort (EC; n = 44), treated between 2001 and 2008. A total of 132 teeth was analysed: 62 teeth in the EC (28 teeth in IT cases and 34 teeth in SC cases) and 70 teeth in the LC (34 teeth in IT cases and 36 teeth in SC cases). Long-term clinical and aesthetic outcomes were evaluated. RESULTS: An improvement over time was found in crown length, BoP, papilla, the inclination of incisors, and overall appearance in IT cases and in crown colour and overbite in SC cases. A deterioration over time was found in crown length and BoP among the SC cases. CONCLUSION: Among the IT cases, an improvement in outcomes was noted over time. When comparing SC cases the colour of the crown and overbite had improved, while crown length and BoP had deteriorated over time.

Comparison of GUMMETAL® and stainless steel alloy during canine retraction: A pilot split-mouth randomized controlled trial.

OBJECTIVES: A TiNb alloy wire (GUMMETAL® [GM], Toyota Central R&D Labs, Inc., Nagakute, Japan) was recently developed with unique properties for orthodontic applications. This pilot split-mouth randomized controlled trial compared maxillary canine retraction during space closure using sliding mechanics on GM vs. stainless steel (SS) archwires. METHODS: Subjects who met the inclusion criteria were treated with fixed appliances and maxillary first-premolar extractions between September 2020 and March 2022. After leveling and aligning, maxillary archwires, fabricated by crimping together segments of 0.016×0.022" GM and SS archwires, were placed and canine retraction initiated using nickel-titanium coil springs. Digital models of the maxillary arch were superimposed at 0, 4, 8 and 12 weeks and the amount of canine movement (mm), rate of movement (mm/month), and 3-dimensional changes (rotational, vertical extrusion, tip) were measured and compared statistically. RESULTS: Of the 12 subjects recruited, only six completed the study with a median age of 15.8 years (12.0-17.4 years). At 12 weeks, the median canine retraction was 3.41mm (IQR: 2.10, 4.76) with GM versus 3.71mm (IQR: 1.62, 6.45) with SS. The retraction rate was 1.14mm/month (IQR: 0.69, 1.59) with GM, versus 1.24mm/month (IQR: 0.54, 2.15) with SS. The median rotational, vertical and tip changes of the canine were 7.90̊, 0.59mm and 6.15̊ with GM, and 7.25̊, 0.29mm and 2.05̊ with SS. Intergroup differences with all measurements were not statistically significant. CONCLUSION: No significant differences were found between GM and SS during maxillary canine retraction. GM demonstrated clinical potential for space closure mechanics, however, future larger studies are needed.

The effect of early versus delayed space closure on the rate of orthodontic tooth movement: a systematic review and meta-analysis.

BACKGROUND: Orthodontic space closure of extraction sites can be initiated early, within 1-week post-extraction, or it can be delayed for a month or more. OBJECTIVE: This systematic review aimed to evaluate the effect of early versus delayed initiation of space closure after tooth extraction on the rate of orthodontic tooth movement. SEARCH METHODS: Unrestricted search of 10 electronic databases was conducted until September 2022. SELECTION CRITERIA: Randomized controlled trials (RCTs) investigating the initiation time of space closure of extraction sites in patients undergoing orthodontic treatment were included. DATA COLLECTION AND ANALYSIS: Data items were extracted using a pre-piloted extraction form. The Cochrane's risk of bias tool (ROB 2.0) and the Grading of Recommendations, Assessment, Development, and Evaluation approach were used for quality assessment. Meta-analysis was undertaken if there are at least two trials reporting the same outcome. RESULTS: Eleven RCTs met the inclusion criteria. Meta-analysis revealed that early canine retraction resulted in a statistically significant higher rate of maxillary canine retraction when compared to delayed canine retraction [mean difference (MD); 0.17 mm/month, 95% CI: 0.06 to 0.28, P = 0.003, 4 RCTs, moderate quality]. Duration of space closure was shorter in the early space closure group, but not statistically significant (MD; 1.11 months, 95% CI: -0.27 to 2.49, P = 0.11, 2 RCTs, low quality). The incidence of gingival invaginations was not statistically different between early and delayed space closure groups (Odds ratio; 0.79, 95% CI: 0.27 to 2.29, 2 RCTs, P = 0.66, very low quality). Qualitative synthesis found no statistically significant differences between the two groups regarding anchorage loss, root resorption, tooth tipping, and alveolar bone height. CONCLUSIONS: Based on the available evidence, early traction within the first week after tooth extraction has a minimal clinically significant effect on the rate of tooth movement compared to delayed traction. Further high-quality RCTs with standardized time points and measurement methods are still needed. REGISTRATION: PROSPERO (CRD42022346026).

Vectores de fuerza generados con microimplantes en la retrusión en masa del sector anterosuperior / Force vectors generated by microimplants in the mass retrusion of the anterosuperior sector

La incorporación de los microimplantes a la ortodoncia revoluciona la mecánica de cierre de espacios por deslizamiento, ya que mejora sus dos puntos "débiles": el anclaje y el control dentario tridimensional. El propósito de este trabajo es determinar los vectores de fuerza y el tipo de movimiento generado en la retrusión en masa del sector anterosuperior, según las distintas ubicaciones de los microtornillos y la altura del brazo de la palanca anterior. Las nuevas tendencias de utilización de microimplantes para la retrusión producen vectores de fuerza horizontales y verticales y momentos según su ubicación y según el punto de aplicación de la fuerza. Debido a esto último, el conocimiento de la biomecánica adquiere especial importancia para un correcto resultado final en el tratamiento ortodóncico. Un diagnóstico certero, un objetivo de tratamiento claro y realista y la elección de la aparatología correcta se verán frustrados una y otra vez de no contar con un correcto conocimiento de las reacciones biológicas ante las fuerzas ejercidas (AU)

The incorporation of miniscrew into orthodontics revolutionizes the mechanics of sliding closure spaces, since it improves its two "weak" points: anchoring and three-dimensional dental control. The purpose of this work is to determine the force vectors and the type of movement generated in the mass retrusion of the anterior superior sector according to the different miniscrew´s locations and the anterior lever arm´s height. The new trends in the use of miniscrews for retrusion produce horizontal and vertical force vectors and moments according to their location and the point of application. In consequence, the knowledge of biomechanics acquires special importance to get a correct final result in orthodontic treatment. Not having a detailed knowledge of the biological reactions on the forces exerted will cause that the accurate diagnosis, the clear and realistic treatment objective, and the choice of the correct appliances to be frustrated over and over (AU)

Finite element analysis of the effect of power arm locations on tooth movement in extraction space closure with miniscrew anchorage in customized lingual orthodontic treatment.

INTRODUCTION: More patients are choosing customized orthodontic appliances because of their excellent esthetics. It is essential that clinicians understand the biomechanics of the tooth movement tendency in customized lingual orthodontics. This study aimed to evaluate the tooth movement tendency during space closure in maxillary anterior teeth with the use of miniscrew anchorage in customized lingual orthodontics with various power arm locations. METHODS: Three-dimensional finite element models of the maxilla were created with miniscrews and power arms; the positions were varied to change the force directions. A retraction force (1.5 N) was applied from the top of the miniscrews to the selected points on the power arm, and the initial displacements of the reference nodes of the maxillary teeth were analyzed. RESULTS: After applying force in different directions, power arms located at the distal side of the canines led to larger initial lingual crown tipping and occlusal crown extrusion of the maxillary incisors compared with power arms located at the midpoint between the lateral incisors and canines, and caused a decreasing trend of the intercanine width. CONCLUSIONS: In customized lingual orthodontic treatment, power arms located at the distal side of the canines are unfavorable for anterior teeth torque control and intercanine width control. Power arms located at the midpoint between the lateral incisors and canines can get better torque control, but still cannot achieve excepted torque without extra torque control methods, no matter whether its force application point is higher than, lower than, or equal to the level of the top of the miniscrews.

Maxillary molar mesialization with the use of palatal mini-implants for direct anchorage in an adolescent patient.

A unique clinical challenge presents when dealing with a compromised first permanent molar. A compelling treatment option for consideration is the removal of a nonrestorable first permanent molar, with the subsequent "replacement" through controlled mesial tooth movement of viable second and third molars. To reinforce the anchorage support associated with such a planned movement, indirect or direct implant-supported mechanics may be used. With the use of direct anchorage, orthodontic brackets are not required and space closure can be commenced immediately. In this article, we report the clinical procedure and design of direct-anchorage mechanics used for the successful closure of a maxillary first permanent molar space with the use of an implant-supported appliance (Mesialslider). Treatment was completed in just under 12 months, with successful mesial movement of the maxillary second and third molars without the need for the bonding of orthodontic brackets on the anterior dentition. The result was determined to be stable over a 3-year period.

Three-dimensional finite element analysis to evaluate biomechanical effects of different alveolar decortication approaches on rate of canine retraction.

INTRODUCTION: The aim of this study was to compare different corticotomy approaches and determine their biomechanical effects on rate of canine displacement when compared to conventional orthodontics. METHOD: Three-dimensional Finite Element Models with conventional non-corticotomy approach (model 1) and three corticotomy approaches ensuing buccal and palatal vertical cuts (model 2), interseptal bone reduction (model 3), buccal vertical cuts (model 4) were fabricated. Displacement of the canine and von Mises stresses in the canine and trabecular bone were calculated and compared under a distal retraction force of 1.5N. RESULTS: The maximum displacement of canine with minimum anchorage loss was seen in model 3 followed by model 2, model 4 and model 1. The maximum equivalent (von Mises) stress was concentrated mainly on the distal side of canine in model 3 and had a uniform distribution of stresses on entire root surface. CONCLUSIONS: Corticotomy approaches effectively accelerated maxillary canine retraction, exhibiting twice the rate of canine movement with minimum anchorage loss when compared to non-corticotomy approach. Corticotomy with interseptal bone reduction was most effective in terms of canine displacement and stress distribution.

Patient with asymmetric multiple hypodontia treated with autotransplantation of 2 premolars.

Tooth autotransplantation is performed in patients with congenitally missing teeth and those with traumatic tooth loss. We report a course of edgewise treatment of a girl with multiple congenitally missing teeth and residual features of ectodermal dysplasia, who was treated with autotransplantation of 2 premolars with developing roots. She was 8 years old at the beginning of the treatment. No signs of inflammation, root resorption, or pulp symptoms were observed during the 2.5 years of edgewise treatment after autotransplantation. Cervical external root resorption was detected 31 months postoperatively in 1 transplanted tooth (maxillary first premolar), and the same problem occurred in the other transplanted tooth (mandibular second premolar) 2 years later. Root canal treatment was immediately undertaken and resulted in inhibition of further pathology. Consequently, the survival of both transplanted teeth was achieved. The orthodontic treatment that included intervals related to diagnosis and treatment of root resorption of the transplanted premolars is described in detail.

Application of Enamel Matrix Derivative and Intrusive Orthodontic Movement in the Treatment of Vertical Bony Defects: A Case Report.

This case report presents treatment of a severe localized horizontal bone loss combined with infrabony defects adjacent to pathologically migrated teeth by orthodontic intrusion following a graft of enamel matrix derivative (EMD) without root surface conditioning. The patient was diagnosed with Angle Class II malocclusion, anterior spacing, and pathologically migrated incisors. Graft of EMD mixed with bone materials was applied for periodontal regeneration before orthodontic treatment, and periapical radiographs were taken every 3 months for radiographic evaluation. After closure of anterior spaces by orthodontic treatment, infrabony defects improved dramatically, with a favorable alveolar bone level and periodontal pocket depth.

Mandibular anterior intrusion using miniscrews for skeletal anchorage: A 3-dimensional finite element analysis.

INTRODUCTION: Deepbites can be corrected by intrusion of mandibular anterior teeth. Direct anchorage with miniscrews simplifies complex tooth movements; however, few studies have reported their use for mandibular anterior intrusion. The purpose of this study was to evaluate, by means of the finite element method, initial tooth displacement and periodontal stress distribution using various mandibular anterior intrusion mechanics. Miniscrews were used as skeletal anchorage devices. METHODS: Cone-beam computed tomography scans were used for 3-dimensional reconstruction of the mandible and the mandibular anterior dentition. Models included the 4 incisors with or without the canines. After all surrounding periodontal and bony structures were determined brackets, segmental archwires, and miniscrews were added. Finite element studies were performed to assess initial tooth displacement and periodontal stress distribution with multiple intrusion force vectors. Changes in the location of the miniscrews and loading points on the archwire created 14 scenarios. RESULTS: Minimum buccolingual displacements, a uniform distribution of periodontal stress, and overall group intrusion for both 4-tooth and 6-tooth scenarios were best achieved when applying distointrusive vectors. The highest peaks of periodontal stress were observed when the force was directed at the corners of the segmental archwire. It was found that, in addition to distointrusive vectors, 4 loading points on the archwire were necessary for pure intrusion and uniform distribution of periodontal stress in the 6-tooth scenarios. CONCLUSIONS: The simulations in this study suggest that group intrusion of all 6 mandibular anterior teeth might be achieved by applying distointrusive vectors. Inserting a pair of miniscrews distal to the canine roots, 1 screw per side, and directing 4 loading points on the archwire generates uniform periodontal stress distribution and minimum buccolingual displacements. Local conditions, such as narrow bone width and attached gingiva level, play significant roles in the clinical viability of the proposed virtual scenarios.

Canine Retraction Using a Closed Nickel Titanium Coil Spring and an Elastic Module.

OBJECTIVE: To compare the mean change of tooth movement in canine retraction between elastic module and Ni Ti coil spring. STUDY DESIGN: Comparative study. PLACE AND DURATION OF STUDY: Orthodontics Department, Armed Forces Institute of Dentistry, Rawalpindi, from May 2015 to January 2016. METHODOLOGY: Thirty-two patients were inducted. After alignment and extraction of maxillary first premolars, canine retraction was started with closed Ni Ti coil spring on one side of the maxillary arch and with active tie back on the other side. The distance between the lateral incisor and the canine was measured on both sides before starting canine retraction. The same measurements were recorded after four weeks of retraction. The difference between pre and post retraction measurements was recorded. The difference in the rate of canine retraction between both modalities was compared using independent sample t-test. RESULTS: The study included 56% females and 43% males. The mean rate of tooth movement in Ni Ti coil group and in the elastomeric module group was 1.1 mm and 0.7 mm in one month, respectively (p=0.05). CONCLUSION: The rate of tooth movement is more rapid with Ni Ti coil spring than with the elastomeric module.

Agenesis of the upper lateral incisors: Study of an orthodontic population and clinical illustration.

In his daily practice, the orthodontist is regularly asked to treat patients with one or more missing teeth. Considering their functional and esthetic specificities, and the relatively high frequency of agenesia, our interest was to focus on the permanent lateral upper incisors. Our study, based on an orthodontic population including 1000 patients, shows that about 7.8% of these patients present agenesis of at least one permanent tooth (out of which 3.6% are agenesis of the upper lateral incisor). Treatment options for these cases are multiple with several decisional factors to consider: the solutions often lead to compromises, and require a multidisciplinary coordination. Therefore, the purpose of this article, was to describe the prevalence of these agenesia based on a retrospective study, and to present two clinical cases: the first case is a bilateral agenesis of the maxillary lateral incisors treated with space opening in order to place two implant-supported restorations. The second case is an agenesis of tooth 12 treated with space reopening and the placement of a cantilever bridge. These clinical cases are presented to illustrate the multidisciplinary approach involving orthodontics, prosthodontics, and periodontology, in order to achieve the most esthetic and functional results possible.

Effectiveness of en masse versus two-step retraction: a systematic review and meta-analysis.

BACKGROUND: This review aims to compare the effectiveness of en masse and two-step retraction methods during orthodontic space closure regarding anchorage preservation and anterior segment retraction and to assess their effect on the duration of treatment and root resorption. METHODS: An electronic search for potentially eligible randomized controlled trials and prospective controlled trials was performed in five electronic databases up to July 2017. The process of study selection, data extraction, and quality assessment was performed by two reviewers independently. A narrative review is presented in addition to a quantitative synthesis of the pooled results where possible. The Cochrane risk of bias tool and the Newcastle-Ottawa Scale were used for the methodological quality assessment of the included studies. RESULTS: Eight studies were included in the qualitative synthesis in this review. Four studies were included in the quantitative synthesis. En masse/miniscrew combination showed a statistically significant standard mean difference regarding anchorage preservation - 2.55 mm (95% CI - 2.99 to - 2.11) and the amount of upper incisor retraction - 0.38 mm (95% CI - 0.70 to - 0.06) when compared to a two-step/conventional anchorage combination. Qualitative synthesis suggested that en masse retraction requires less time than two-step retraction with no difference in the amount of root resorption. CONCLUSIONS: Both en masse and two-step retraction methods are effective during the space closure phase. The en masse/miniscrew combination is superior to the two-step/conventional anchorage combination with regard to anchorage preservation and amount of retraction. Limited evidence suggests that anchorage reinforcement with a headgear produces similar results with both retraction methods. Limited evidence also suggests that en masse retraction may require less time and that no significant differences exist in the amount of root resorption between the two methods.

A new orthodontic force system for moment control utilizing the flexibility of common wires: Evaluation of the effect of contractile force and hook length.

BACKGROUND/PURPOSE: The application of an appropriate force system is indispensable for successful orthodontic treatments. Second-order moment control is especially important in many clinical situations, so we developed a new force system composed of a straight orthodontic wire and two crimpable hooks of different lengths to produce the second-order moment. The objective of this study was to evaluate this new force system and determine an optimum condition that could be used in clinics. METHODS: We built a premolar extraction model with two teeth according to the concept of a modified orthodontic simulator. This system was activated by applying contractile force from two hooks that generated second-order moment and force. The experimental device incorporated two sensors, and forces and moments were measured along six axes. We changed the contractile force and hook length to elucidate their effects. Three types of commercial wires were tested. RESULTS: The second-order moment was greater on the longer hook side of the model. Vertical force balanced the difference in moments between the two teeth. Greater contractile force generated a greater second-order moment, which reached a limit of 150 g. Excessive contractile force induced more undesired reactions in the other direction. Longer hooks induced greater moment generation, reaching their limit at 10 mm in length. CONCLUSION: The system acted similar to an off-center V-bend and can be applied in clinical practice as an unconventional loop design. We suggest that this force system has the potential for second-order moment control in clinical applications.

Stability of first and second premolars extraction space closure / Estabilidade do fechamento dos espaços de extrações dos primeiros e segundos pré-molares

Premolars are the most commonly extracted teeth to provide space to correct crowding and excessive labial protrusion. After treatment, the extraction spaces have to remain closed. Nevertheless, several studies have shown that there is a tendency for some relapse even in patients finished with an adequate occlusion. The objective of this study was to compare the stability of extraction space closure of the first and second premolars. A sample 72 patients´ dental casts were divided into two groups. Group 1, comprised 29 patients (116 extraction spaces) were treated with first premolar extractions at a mean initial age of 13.78 years and group 2, comprised 43 patients (100 extraction spaces) were treated with second premolar extractions at a mean initial age of 15.20 years. The dental casts obtained at pretrement, posttreament and a between 3 to 4 years postretention were digitized using a 3- dimensional scanner (R700; 3Shape,Copenhagen, Denmark). Chi-Square tests were used to compare the numbers of open and closed extraction spaces after treatment and at long-term posttreatment. T tests were used to compare the amount of spaces at posttreatment and at the long-term posttreatment stages. These tests were also performed in subgroups with completely closed extraction sites at posttreatment. The groups showed similar numbers of extraction sites reopening. First and second premolar extraction space closure present a similar tendency for reopening. Considering only the cases that showed completely closed extraction spaces in the final dental models, extraction space reopening was larger in the first premolar extraction group in the maxillary arch.(AU)

Os pré-molares são os dentes mais comumente extraídos para corrigir o apinhamento dentário e à protrusão labial excessiva. Após o tratamento, os espaços das extrações deveriam permanecer fechados. Contudo, muitos estudos demostraram que existe uma tendência à reabertura dos espaços de extrações em pacientes finalizados com uma oclusão adequada. O objetivo deste estudo foi comparar a estabilidade dos espaços de extrações de primeiro e segundo prémolares. A Amostra deste estudo foi composta por 72 modelos dentários dividido em dois grupos. O Grupo 1 composto por 29 pacientes (116 espaços de extração) foram tratados com extrações dos primeiros pré-molares com idade media inicial de 13,78 anos e o grupo 2 composto por 43 pacientes (100 espaços de extração) foram tratados com extrações dos segundos pré-molares com idade media inicial de 15.20 anos. Os modelos dentários obtidos no pré-tratamento, pós-tratamento e 3 a 4 anos de controle e foram digitalizados mediante um scanner 3Shape R700 3D (3Shape A/S, Copenhagen, Dinamarca). Os testes t e do Qui-Quadrado, foram utilizados para comparar o número de espaços de extração abertos e fechados após o tratamento e pós-tratamento em longo prazo. Os resultados demostraram números similares de reabertura do espaço de extração entre os grupos. Concluiu-se que considerando apenas os casos que mostraram espaços de extração completamente fechados no final do tratamento, a quantidade de reabertura dos espaços de extrações dos primeiros pré-molares ocorre mais frequentemente que dos segundos pré-molares no arco superior.(AU)

Influence of interradicular and palatal placement of orthodontic mini-implants on the success (survival) rate.

BACKGROUND: The purpose of this retrospective cohort study was to investigate the success rates of orthodontic mini-implants (OMIs) placed in different insertion sites and to analyse patient and site- related factors that influence mini-implant survival. METHODS: Three hundred eighty-seven OMIs were inserted in 239 patients for orthodontic anchorage and were loaded with a force greater than 2 N. Two different insertion sites were compared: 1. buccal inter-radicular and 2. palatal, at the level of the third palatal ruga. Survival was analysed for location and select patient parameters (age, gender and oral hygiene). The level of statistical significance was set at p < 0.05. RESULTS: The overall success rate was 89.1%. There were statistically significant differences between insertion sites; success rate was 98.4% for OMIs placed in the anterior palate and 71% for OMIs inserted buccal between roots (p < 0.001). CONCLUSIONS: Success rate of OMIs was primarily affected by the insertion site. The anterior palate was a more successful location compared to buccal alveolar bone.

Incidence and severity of gingival invaginations associated with early versus late initiation of orthodontic space closure after tooth extraction : A multicenter pilot and randomized controlled trial.

OBJECTIVE: Gingival invaginations are a common side effect of orthodontic extraction-space closure. The timing of initiating the closure of an extraction space varies greatly in clinical practice. In this multicenter pilot and randomized controlled trial, we prospectively investigated whether initiating space closure in the early stage of wound healing would benefit the incidence and severity of invaginations developing in the extraction sites. METHODS: A total of 368 patients were screened for indications to extract at least one mandibular premolar. Those recruited were randomly assigned to one of two treatment arms: initiation of space closure either 2-4 weeks (arm A) or ≥12 weeks (arm B) after tooth extraction. Clinical data regarding treatment process and periodontal tissue response were recorded during and after space closure and analyzed by a specialized biometrics unit. The study was performed under continuous surveillance by an independent study control center. RESULTS: A total of 74 extraction sites were analyzed. Regarding the incidence of gingival invaginations, there were no significant intergroup differences [p = 0.13; group A comprising 37/44 (84.1%) and group B 29/30 (96.7%) invaginated sites]. The same was true based on either maxillary (p = 0.52) or mandibular (p = 0.21) sites only, and the severity of the invaginations did not differ between the treatment arms. CONCLUSIONS: As to the incidence and severity of gingival invaginations, we did not notice any statistically significant differences between the two timeframes. Our data do, however, provide a basis to identify additional confounders and to improve the accuracy of case-load estimations for future trials.