Orthodontic treatment as an adjunct to periodontal therapy

ABSTRACT This study discusses the role of orthodontic treatment as an adjunct to the control and treatment of periodontal disease conditions, and describes a clinical case of severe anterior mandibular crowding and periodontal disease followed up for nine years and three months after orthodontic treatment completion. Malocclusion impaired proper dental hygiene, which led to bone loss and development of a periodontal abscess between mandibular canines and lateral incisors. After scaling and root planing, orthodontic treatment was initiated with extraction of the four second premolars, to correct the deficiency detected in cephalometric and model analysis. Treatment objectives were met, and facial and dental esthetics was satisfactory. Adequate periodontal management, hygiene control and tooth movement ensured ideal occlusion and facilitated the control of biofilm.

RESUMO Os objetivos do presente artigo são discutir o papel do tratamento ortodôntico como coadjuvante no controle e tratamento dos problemas periodontais e apresentar um caso clínico com severo apinhamento anteroinferior e problemas periodontais, com acompanhamento de 9 anos e 3 meses após o tratamento ortodôntico. A má oclusão impossibilitava a correta higienização dos dentes, causando perda óssea e abscesso periodontal entre os caninos e incisivos laterais inferiores. Após a raspagem e alisamento radicular, o tratamento ortodôntico foi realizado com extrações dos quatro segundos pré-molares, para corrigir a discrepância cefalométrica e de modelos. Os objetivos do tratamento foram alcançados com satisfatória estética facial e dentária. O adequado manejo do periodonto, controle da higiene bucal e da movimentação dentária permitiram atingir uma oclusão ideal e facilitar o controle de placa bacteriana.

Importance of periodontal ligament thickness

This study evaluated whether periodontal ligament (PL) thickness varied with root size and examined the possible influence of this variation on orthodontic mechanics. Measurements were taken of the maxillary left first molar in 54 male Wistar rats. Mean mesial and distal PL thicknesses were compared between the intermediate buccal and mesiobuccal roots using paired Student's t-tests with a 5% significance level. Mean values differed significantly between roots (p < 2.2 × 10-16). PL thickness in rats is directly proportional to root dimensions.

Effect of heat treatment on stainless steel orthodontic wires

This study evaluated the effect of heat treatment on CrNi stainless steel orthodontic archwires. Half of forty archwires of each thickness - 0.014" (0.35 mm), 0.016" (0.40 mm), 0.018" (0.45 mm) and 0.020" (0.50 mm) (totalling 160 archwires) - were subjected to heat treatment while the remainder were not. All of the archwires had their individual thickness measured in the anterior and posterior regions using AutoCad 2000 software before and after compressive and tensile strength testing. The data was statistically analysed utilising multivariance ANOVA at a 5 percent significance level. All archwires without heat treatment that were subjected to tensile strength testing presented with anterior opening, which was more accentuated in the 0.020" archwires. In the posterior region, the opening produced by the tensile force was more accentuated in the archwires without heat treatment. There was greater stability in the thermally treated archwires, especially those subjected to tensile strength testing, which indicates that the heat treatment of orthodontic archwires establishes a favourable and indispensable condition to preserve the intercanine width.

Avaliação histomorfométrica da movimentação dentária induzida em ratos com força contínua, contínua interrompida e intermitente / Histomorphometric evaluation of tooth movement in rats with continuous, continuous interrupted and intermitent forces

Introdução: O presente trabalho apresenta uma metodologia para a movimentação dentária induzida (MDI) e avalia a quantidade de movimentação dentária, as condições ósseas, radiculares e periodontais, após o emprego de força contínua (FC), contínua interrompida (FCI) e intermitente (FI). Material e Métodos: Utilizou-se 54 ratos da linhagem Wistar, em grupos de FC, FCI e FI, nos períodos de 5, 7 e 9 dias. Inicialmente foram realizadas extrações dos incisivos superiores direitos de cada animal, e procedeu-se a obturação retrógrada e reimplante imediato para indução de anquilose. Após 2 semanas, instalou-se molas de NiTi (Sentalloy) com liberação de 50cN de magnitude de força, sendo mantidas, desativadas ou removidas em determinados períodos para estabelecer os tipos de força, FC, FCI e FI. Os dados foram comparados pela análise de variância (ANOVA) e teste de Tukey com nível de significância de 5%. Resultados: Nenhum incisivo induzido à anquilose apresentou erupção ou movimentação após o emprego de forças. A análise histológica demonstrou que todos os incisivos manipulados apresentaram anquilose. Não houve diferença na quantidade de movimentação entre os grupos FC e FCI, que diferiram de forma estatisticamente significante do FI. Ocorreu maior formação de áreas hialinas no grupo FC, principalmente, no 5º dia de movimentação. Não houve diferença significativa na reabsorção radicular entre os grupos. A avaliação do ligamento periodontal nos molares não movimentados mostrou que a espessura na raiz intermediária é menor do que na raiz mesiovestibular, com diferença estatisticamente significante. Conclusões: A metodologia para indução de anquilose mostrou-se eficaz para a utilização como ancoragem, durante a MDI dos molares murinos, eliminando os efeitos indesejáveis consequentes da erupção contínua dos incisivos. As forças contínuas produzem mais áreas hialinas com maior probabilidade de gerar reabsorções radiculares. As forças contínuas interrompidas possibilitam...

Introduction: This paper presents a methodology for induced tooth movement (MDI) and assesses the amount of tooth movement, bone, root and periodontal conditions with continuous (FC), continuous interrupted (FCI) and intermittent (FI) forces. Methods: 54 Wistar rats were used in groups of FC, FCI and FI, in periods of 5, 7 and 9 days. In the upper right incisor of each animal was held extraction, retrograde filling and reimplantation for immediate induction of ankylosis. After two weeks, were installed opened springs NiTi (Sentalloy), releasing 50cN magnitude of force, being maintained, disabled or removed in certain periods to establish the types of force, FC, FCI e FI. Data were compared by analysis of variance (ANOVA) and Tukey’s test with a significance level of 5%. Results: None of the incisor induced ankylosis had eruption or movement after the employment of forces, and the eruption rate was zero. Histological examination showed that all of manipulated incisors had ankylosis. There was no difference in the amount of movement between groups FC and FCI, which differed statistically from FI. There was greater formation of hyaline areas in the FC group mainly on the 5th day. There was no significant difference in root resorption between the groups. In molars not moved, the thickness of the periodontal ligament in the middle root is smaller than in the mesiobuccal root, with statistically significant difference. Conclusions: The methodology for inducing ankylosis was effective for use as an anchorage during murine molar MDI. It eliminates the undesirable effects resulting from the continuous eruption of incisors. The continuous forces produce more hyaline areas most likely to generate root resorption. The continuous interrupted forces allow a better ligament repair and more efficient elimination of hyalinized zones. The thickness of the periodontal ligament is directly proportional to the size of roots. The difference in the intensity of the same magnitude

Avaliação histomorfométrica da movimentação dentária induzida em ratos com força contínua, contínua interrompida e intermitente / Histomorphometric evaluation of tooth movement in rats with continuous, continuous interrupted and intermitent forces

Introdução: O presente trabalho apresenta uma metodologia para a movimentação dentária induzida (MDI) e avalia a quantidade de movimentação dentária, as condições ósseas, radiculares e periodontais, após o emprego de força contínua (FC), contínua interrompida (FCI) e intermitente (FI). Material e Métodos: Utilizou-se 54 ratos da linhagem Wistar, em grupos de FC, FCI e FI, nos períodos de 5, 7 e 9 dias. Inicialmente foram realizadas extrações dos incisivos superiores direitos de cada animal, e procedeu-se a obturação retrógrada e reimplante imediato para indução de anquilose. Após 2 semanas, instalou-se molas de NiTi (Sentalloy) com liberação de 50cN de magnitude de força, sendo mantidas, desativadas ou removidas em determinados períodos para estabelecer os tipos de força, FC, FCI e FI. Os dados foram comparados pela análise de variância (ANOVA) e teste de Tukey com nível de significância de 5%. Resultados: Nenhum incisivo induzido à anquilose apresentou erupção ou movimentação após o emprego de forças. A análise histológica demonstrou que todos os incisivos manipulados apresentaram anquilose. Não houve diferença na quantidade de movimentação entre os grupos FC e FCI, que diferiram de forma estatisticamente significante do FI. Ocorreu maior formação de áreas hialinas no grupo FC, principalmente, no 5º dia de movimentação. Não houve diferença significativa na reabsorção radicular entre os grupos. A avaliação do ligamento periodontal nos molares não movimentados mostrou que a espessura na raiz intermediária é menor do que na raiz mesiovestibular, com diferença estatisticamente significante. Conclusões: A metodologia para indução de anquilose mostrou-se eficaz para a utilização como ancoragem, durante a MDI dos molares murinos, eliminando os efeitos indesejáveis consequentes da erupção contínua dos incisivos. As forças contínuas produzem mais áreas hialinas com maior probabilidade de gerar reabsorções radiculares. As forças contínuas interrompidas possibilitam...

Introduction: This paper presents a methodology for induced tooth movement (MDI) and assesses the amount of tooth movement, bone, root and periodontal conditions with continuous (FC), continuous interrupted (FCI) and intermittent (FI) forces. Methods: 54 Wistar rats were used in groups of FC, FCI and FI, in periods of 5, 7 and 9 days. In the upper right incisor of each animal was held extraction, retrograde filling and reimplantation for immediate induction of ankylosis. After two weeks, were installed opened springs NiTi (Sentalloy), releasing 50cN magnitude of force, being maintained, disabled or removed in certain periods to establish the types of force, FC, FCI e FI. Data were compared by analysis of variance (ANOVA) and Tukey’s test with a significance level of 5%. Results: None of the incisor induced ankylosis had eruption or movement after the employment of forces, and the eruption rate was zero. Histological examination showed that all of manipulated incisors had ankylosis. There was no difference in the amount of movement between groups FC and FCI, which differed statistically from FI. There was greater formation of hyaline areas in the FC group mainly on the 5th day. There was no significant difference in root resorption between the groups. In molars not moved, the thickness of the periodontal ligament in the middle root is smaller than in the mesiobuccal root, with statistically significant difference. Conclusions: The methodology for inducing ankylosis was effective for use as an anchorage during murine molar MDI. It eliminates the undesirable effects resulting from the continuous eruption of incisors. The continuous forces produce more hyaline areas most likely to generate root resorption. The continuous interrupted forces allow a better ligament repair and more efficient elimination of hyalinized zones. The thickness of the periodontal ligament is directly proportional to the size of roots. The difference in the intensity of the same magnitude

Knowledge on dental trauma and orthodontic tooth movement held by a group of orthodontists

The objective of this work was to assess the knowledge about orthodontic tooth movement and dental trauma held by a group of orthodontists in specific areas of Brazil. For this purpose, 166 questionnaires with 15 objective questions about this subject were distributed. One hundred and five questionnaires were properly filled and collected after 30 days. It was concluded that, except for avulsion, the knowledge on dental injuries held by the professionals interviewed was considered unsatisfactory, and about 40 percent of them were not acquainted with the recommendations for the orthodontic movement of traumatized teeth.

Compensatory canine angulation in angle Class II and III patients

The aim of this study was to evaluate the occurence of compensation in mesiodistal axial inclinations of canines in skeletal malocclusions patients. The sample consisted of 25 Angle Class II, division 1 malocclusion (group 1) and 19 Angle Class III malocclusion patients (group 2). After measurement of dental angulations through a method that associates plaster model photography and AutoCad software, comparisons between the groups were performed by T-test for independent samples. Results showed that there was no statistically significant difference (p < 0.05) between groups, when maxillary canine angulations were compared. Regarding the mandibular canines, there was a statistically significant difference in dental angulation, expressed by 3.2° for group 1 and 0.15° for group 2. An upright position tendency for mandibular canines was observed in the Angle Class III sample. This configures a pattern of compensatory coronary positioning, since the angulation of these teeth makes them occupy less space in the dental arch and consequently mandibular incisors can be in a more retracted position in the sagittal plane.