Orthodontic Mechanics Research Articles

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

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

The effects of non-extraction orthodontic treatment on the vertical dimension: a comparison of a dolichofacial and a mesofacial group

Abstract Objective: The decision regarding extraction or non-extraction orthodontic treatment for patients with different skeletal facial patterns is more commonly based on traditional concepts rather than scientific facts. The present study aimed to investigate whether dolichofacial patients responded differently compared with mesofacial patients to non-extraction orthodontic treatment with respect to vertical changes in facial height. Methods: Twenty-eight dolichofacial patients and 29 mesofacial patients who underwent non-extraction orthodontic treatment were selected. All patients commenced treatment prior to 15 years of age and had a mean age of 12.3 years for the dolichofacial group and 12.6 years for the mesofacial group. Serial lateral cephalometric radiographs were traced by hand on acetate paper and digitised using the Rocky Mountain Orthodontics JOE 32 programme. Statistical analysis examined the recorded changes in facial axis angle, facial angle, menton-to-ANS distance and facial convexity. Results: An increase in menton-to-ANS distance and facial angle and a decrease in facial convexity were observed in both groups to a similar extent. Interestingly, the facial axis of both groups remained constant throughout treatment and up to two years post-treatment. Both groups showed slightly increased facial axis angle beyond the original value at two years post-treatment. No statistically significant difference between the two groups was observed in the changes of any of the variables over time. Conclusion: The results countered the traditional concept that dolichofacial patients would have an increased facial height after being subjected to non-extraction orthodontic mechanics. It appeared that long-term vertical height of the face was more dependent on genetics rather than environmental influences.

Orthodontic Implants: Concepts for the Orthodontic Practitioner

Orthodontic implants have become a reliable method in orthodontic practice for providing temporary additional anchorage. These devices are useful to control skeletal anchorage in less compliant patients or in cases where absolute anchorage is necessary. There are a great number of advantages in this new approach which include easy insertion, decreased patient discomfort, low price, immediate loading, reduced diameter, versatility in the forces to be used, ease of cleaning, and ease of removal. However, a proper management of the screws by the practitioner is necessary in order to increase the success rate of the technique. The purpose of this paper is to update practitioners on the current concepts of orthodontic implants and orthodontic mechanics.

Comparison of the Anterior Limit of the Dentition in Patients Treated with Self-Ligating Straight-Wire, Conventional Straight-Wire and Standard Edgewise Appliances

The aim of this study was to identify and compare any differences in the position of the anterior limit of the dentition provoked by three different types of orthodontic mechanics: traditional edgewise, straightwire and self-ligating. A sample of 54 patients (selected from a group of 289 patients) possessed a range of Little's Irregularity Index values for the upper and lower dental arches between a minimum of 6.5 and a maximum of 13.5 at T0, and corresponding final values no greater than 2 and hence of minimal irregularity. The 54 patients were subdivided into three groups according to the type of brackets used in their treatment: Group 1 was composed of 24 patients treated using the self-ligating technique, Group 2 of 15 patients treated using a conventional straight-wire technique (Roth) and Group 3 of 15 patients treated using the standard edgewise technique. Cephalometric tracings were performed on laterolateral teleradiography. Group 1 value was found to be nonsignificant, whereas significant labial inclination was noted in Groups 2 and 3 (P < 0.05). A significant labial inclination of the upper incisors was also evidenced in all three sample groups.

Impacted canines: Etiology, diagnosis, and orthodontic management

Impaction of maxillary and mandibular canines is a frequently encountered clinical problem, the treatment of which usually requires an interdisciplinary approach. Surgical exposure of the impacted tooth and the complex orthodontic mechanisms that are applied to align the tooth into the arch may lead to varying amounts of damage to the supporting structures of the tooth, not to mention the long treatment duration and the financial burden to the patient. Hence, it seems worthwhile to focus on the means of early diagnosis and interception of this clinical situation. In the present article, an overview of the incidence and sequelae, as well as the surgical, periodontal, and orthodontic considerations in the management of impacted canines is presented.

Long-term skeletal and dental stability of mandibular symphyseal distraction osteogenesis with a hybrid distractor

The purpose of this study was to examine the long-term skeletal and dental stability of mandibular symphyseal distraction osteogenesis (MSDO) with a tooth-borne and bone-borne hybrid distractor. To differentiate the effects of MSDO from the orthodontic movement and relapse, each phase of treatment was analyzed. Twenty-five patients were included in the study, ranging in age from 12.0 to 30.9 years at the initiation of treatment (mean, 15.8 ± 4.8 years). Of this group, 16 patients were recalled at a mean of 7.5 ± 0.9 years (range, 6.3-9.6 years) after distraction for long-term analysis of skeletal and dental changes. Orthodontic records were taken at 5 times: T1, pretreatment; T2, predistraction; T3, postdistraction; T4, posttreatment, and T5, postretention. The data were statistically analyzed by using repeated-measures analysis of variance (ANOVA). There were significant increases in all interdental transverse measurements except the mandibular intersecond molar distance from T1 to T4. The largest overall expansion was achieved between the mandibular second premolars (4.32 ± 0.60 mm), followed by the interfirst premolar (3.44 ± 0.44 mm), the interfirst molar (2.60 ± 0.65 mm), and the intercanine (1.87 ± 0.44 mm) widths. The overall amount of transverse dental expansion was substantially less when analyzed from the time of the mandibular symphyseal osteotomy to posttreatment (T2-T4). From T3 to T4, there were significant decreases between the mandibular intersecond premolars (-3.10 ± 0.52 mm), interfirst premolars (-3.90 ± 0.35 m), intercanines (-4.47 ± 0.38 mm), and intercentral incisors (-5.60 ± 0.32 mm). There were no significant changes in bicondylar, bigonial, and biantigonial widths. At the long-term follow-up, there were no significant changes in the interdental or skeletal measurements between T4 and T5, except for interincisor apices. The irregularity index significantly decreased during the orthodontic treatment but significantly increased in the long-term follow-up period (T4-T5). After the MSDO, T3 to T5, the results indicated symphyseal basal bone skeletal stability. The results indicate that the expansion of the mandibular arch with MSDO and conventional orthodontic mechanics produces no statistically significant transverse changes from posttreatment to long-term follow-up. The risks of using a surgical procedure and MSDO to achieve additional expansion should be evaluated by the clinician and compared with more traditional orthodontic methods.

Extrações de molares na Ortodontia

O tratamento ortodôntico com extração de molares em pacientes adultos é tecnicamente mais complexo, devido a inúmeros fatores. Em geral, o espaço a ser fechado é maior do que o espaço dos pré-molares e, por isso, a ancoragem é crítica e o tempo de tratamento mais longo. É comum esses casos apresentarem algum grau de comprometimento periodontal por causa da idade dos pacientes e, portanto, necessitam de maior controle da mecânica ortodôntica para reduzir os efeitos colaterais do fechamento do espaço. Por isso, bons resultados de finalização são mais difíceis de ser alcançados. Sendo assim, este artigo tem como objetivo apresentar as razões para a indicação de extração de molares nos tratamentos ortodônticos, as contraindicações, as diferentes fases da mecânica ortodôntica, esclarecer os fatores envolvidos nesse tipo de planejamento e tratamento e apresentar casos clínicos tratados com extração de molares.

Anterior Open Bite Closure: A Case Report

Anterior open bite is often caused by a downward rotation of the mandible and/or by excessive eruption of the posterior teeth. In such cases, it is difficult to establish absolute anchorage for molar intrusion by traditional orthodontic mechanics. This article reports the successful treatment of a severe skeletal anterior open bite case using titanium screw anchorage. A female patient of 31 years of age had open bite of 7 mm with increased facial height. The mini screws were implanted on both maxilla and the mandible, and an intrusion force was provided with elastic chains for 13 months. After active treatment of 19 months, her upper and lower first molars were intruded by about 3 mm each, and good occlusion was achieved. Her retrognathic chin and convex profiles were improved by an upward rotation of the mandible. Our result suggests that titanium screws are useful for intrusion of molars in anterior open bite cases.

Minimally invasive midface distraction for maxillary hypoplasia during growth

The treatment of skeletal anterior open-bite malocclusion requires complex orthodontic planning that considers its multifactorial etiology, treatment limitations, and high relapse rates. This case report illustrates a successful treatment approach for a skeletal high-angle Class II malocclusion in an adult with a severe open bite. The treatment consisted of a high-pull headgear therapy after mini-implants failure during fixed orthodontic therapy. Adequate esthetics and function were achieved. Despite its low probability, the unexpected event of mini-implant loosening during complex treatments should be considered. Therefore, classic orthodontic mechanics should be established, especially when treating patients for whom invasive procedures such as miniplates or orthognathic surgery are not available options.

Biomechanical Anchorage Evaluation of Mini-Implants Treated With Sandblasting and Acid Etching in Orthodontics

The purpose of this study was to assess the stability of sandblasted and acid-etched miniscrew implants based on orthodontic mechanics for space closure after tooth extraction. Twenty-four orthodontic mini-implants were placed in 13 patients, for a skeletal anchorage purpose, all prepared by the manufacturer (3M Unitek-IMTEC Ortho USA) with sandblasting and acid treatment. Anchorage measurements were made on occlusal radiographs, on a monthly basis in a 6-month period. All the mini-implants were effective for the clinical trial; but 65% of the mini-implants, after been loaded, showed up to 1 degree, or less, of displacement, while 35% showed ≥2 degrees shift. The mandible mini-implants resulted in a smaller amount of displacement than the ones located in the maxilla. The ones located at the anterior maxilla displaced less than the posterior. The best results were obtained with the 8-mm mini-implants, followed by the 6-mm and 10-mm mini-implants. Modifying the mini-implant surface with sandblasting and acid treatment offers good bone anchoring for orthodontic purposes.

Imaginologia da articulação temporomandibular durante o tratamento ortodôntico: uma revisão sistemática

INTRODUÇÃO: a evolução da Imaginologia na Odontologia propiciou uma série de vantagens para o diagnóstico e elaboração de planos de tratamento em diversas especialidades. Exames como ressonância magnética nuclear, tomografia computadorizada e tomografia volumétrica Cone Beam, bem como métodos de reconstrução em 3D, permitiram analisar de forma precisa estruturas orofaciais.Aliado a esse fato,com a realização de estudos clínicos com metodologias e desenhos adequados, pode-se avaliar os efeitos do tratamento ortodôntico sobre a articulação temporomandibular (ATM). OBJETIVO: esse trabalho, através de uma revisão sistemática de literatura, teve como objetivo analisar a inter-relação entre o tratamento ortodôntico e a ATM, verificando se a Ortodontia acarreta alguma alteração das estruturas internas da ATM. MÉTODOS: levantamento em bases de pesquisa (MEDLINE, Cochrane, EMBASE, Pubmed, Lilacs e BBO), entre os anos de 1966 e 2009, com enfoque em estudos clínicos randomizados, estudos longitudinais prospectivos não randomizados, revisões sistemáticas e meta-análises. RESULTADOS: após a aplicação dos critérios de inclusão, chegou-se a 14 artigos, sendo que 2 eram estudos clínicos randomizados e 12 eram estudos longitudinais sem critérios de randomização. CONCLUSÕES: pela análise da literatura, conclui-se que a realização do tratamento ortodôntico não ocorre à custa de posicionamentos não fisiológicos do côndilo e disco articular. Algumas mecânicas podem acarretar remodelações dos componentes ósseos articulares.

Transposition of a maxillary canine and a lateral incisor and use of cone-beam computed tomography for treatment planning

This report describes the orthodontic treatment of a 12-year-old girl with transposition of the maxillary left canine and the lateral incisor. Cone-beam computed tomography was used during treatment planning. The transposed tooth positions were corrected with an unconventional orthodontic approach. Treatment alternatives and their clinical concerns are presented.

Application of Temporary Anchorage Devices for the Treatment of Adult Class III Malocclusions

In the treatment of adult mild-to-moderate Class III malocclusions, temporary anchorage devices (TADs) are quite useful when compared with traditional orthodontic mechanics because they allow for group distalization of the mandibular arch dentition without any anchorage loss and the need for patient cooperation. The retromolar area is the most suitable site for TAD insertion, and it is the site of choice in Class III treatment. If there is inadequate attached gingiva in the optimal area where the TAD should be placed, then interradicular alveolar screws can be placed between the second premolar and first molar or between the first and second molars. In the treatment of Class III malocclusions with severe skeletal discrepancies, combined treatment with orthognathic surgery and tooth movement with TADs offers several advantages. TADs may facilitate the surgical procedures and make the pre- and postsurgical orthodontics simpler.

Positioning Miniplates for Orthodontic Anchorage

Titanium miniplates have been used in orthodontic treatment as stable anchorage devices.1-6 The precise height for miniplate placement is essential for effective orthodontic mechanics, and incorrect positioning can make them useless for orthodontic movement. This article describes a simple and practical surgical guide developed to help surgeons and orthodontists in the determination of miniplate placement, making their communication easier.

A review of early displaced maxillary canines: etiology, diagnosis and interceptive treatment.

Impaction of maxillary canines is a frequently encountered clinical problem the treatment of which usually requires an interdisciplinary approach. Surgical exposure of the impacted tooth and the complex orthodontic mechanisms that are applied to align the tooth into the arch may lead to varying amounts of damage to the supporting structures of the tooth, not to mention the long treatment duration and the financial burden to the patient. Hence, it seems worthwhile to focus on the means of early diagnosis and interception of this clinical situation. In the present article, theories related with the etiology of impacted canines and predictive variables of canine impaction in the mixed dentition are reviewed with an insight into current interceptive treatment modalities.

Simulação 3D de movimento ortodôntico

OBJETIVO: desenvolver e validar, através do Método dos Elementos Finitos (MEF), um modelo numérico tridimensional (3D) de um incisivo central superior para simular o movimento dentário. MÉTODOS: esse modelo contempla a unidade dentária, o osso alveolar e o ligamento periodontal. Permite a simulação dos diferentes movimentos dentários e a determinação dos centros de rotação e de resistência. Limita o movimento ao espaço periodontal, registrando a direção, quantificando o deslocamento dentário e as tensões iniciais no ligamento periodontal. RESULTADOS: a análise dos deslocamentos dentários e das áreas que recebem tensões iniciais possibilita determinar os tipos de movimentos dentários. Com base nas forças ortodônticas, é possível quantificar a intensidade das tensões em cada região do dente, do ligamento periodontal ou do osso alveolar. Com base nas tensões axiais ao longo do ligamento periodontal e da tensão capilar, é possível predizer, teoricamente, as regiões em que deve ocorrer a remodelação óssea. CONCLUSÃO: o modelo foi validado pela determinação do módulo de elasticidade do ligamento periodontal de forma compatível com dados experimentais existentes na literatura. Os métodos utilizados na construção do modelo permitiram a criação de um modelo completo para uma arcada dentária, o qual possibilita realizar variadas simulações que envolvem a mecânica ortodôntica.

Preorthodontic Uncovering and Autonomous Eruption of Palatally Impacted Maxillary Canines

Palatally impacted maxillary canines are a challenge for any orthodontist. Often the surgeon will perform an incorrect uncovering technique, the orthodontic mechanics to erupt the tooth could be inappropriate, and as a result the periodontal and esthetic outcome could be disastrous. However, in the adolescent patient, the management of palatally impacted maxillary canines can be predictable, stable, and esthetic. However, to accomplish these results, the orthodontist and surgeon must select the appropriate method of surgical uncovering. This article discusses the advantages of preorthodontic uncovering and autonomous eruption of palatally impacted maxillary canines. The surgical technique will be described and illustrated, and consecutively treated cases will be displayed. An evidence-based discussion will feature the benefits of preorthodontic uncovering and autonomous eruption of palatally impacted maxillary canines.

Treatment of a horizontally impacted mandibular canine in a girl with a Class II Division 1 malocclusion

When a patient has an impacted tooth, the timing of orthodontic treatment, the type of surgical procedure to expose the tooth, the orthodontic mechanics, and the potential problems vary depending on which tooth is impacted and its position in the jaw. This case report describes the successful treatment of a patient with a horizontally impacted mandibular canine. The impacted tooth was surgically exposed and then moved into its normal position in the dental arch, combined with correction of a Class II Division 1 malocclusion.

Orthodontic Treatment of an Ankylosed Maxillary Central Incisor through Osteogenic Distraction

Tooth ankylosis is one of the various problems in dentistry and requires special treatment approaches for satisfactory results. In the orthodontic treatment of an ankylosed tooth, different treatment modalities have been put into practice including both orthodontic and orthodontic-surgical approaches. For favorable results, gingival margin esthetics must be considered as much as leveling the ankylosed tooth in the arch. Distraction osteogenesis accompanied by orthodontic mechanics is a sensible way of achieving this goal. However, devices used in the distraction protocol are high in price and bulky in shape, causing functional and esthetic problems for the patient. This report describes treatment of an infrapositioned ankylosed incisor with continuous distraction forces produced by conventional orthodontic mechanics. In conclusion, the ankylosed tooth was leveled in the upper arch successfully with a harmonic gingival margin.

Loss of anchorage of miniscrews: A 3-dimensional assessment

Miniscrews have exponentially empowered the orthodontic anchorage armamentarium. However, the behavior of miniscrews under loading has not yet been fully investigated. Forty miniscrews were used for retraction of the maxillary and mandibular canines into the spaces of extracted first premolars. After a healing period of 2 weeks, a loading force was applied between 150 and 250 g for 6 months. The displacement of the miniscrews, their placement angles, and their implanted percentages into the bone were assessed by using superimposed 3-dimensional volumes of the maxilla and the mandible before and after 6 months of loading of the miniscrews. Miniscrews were displaced in the direction of orthodontic loading. The displacement was experienced in the movement of the head and tail, and extrusion of the miniscrews. These movements were not correlated with the placement angle or the length of miniscrews in the bone. Movement of miniscrews is to be expected during orthodontic loading. This phenomenon should be considered when determining their dimensions and placement angles to provide the maximum range of action for orthodontic mechanics without midtreatment replacement of miniscrews.