Periodontal ligament hydrostatic pressure with areas of root resorption after application of a continuous torque moment.

OBJECTIVE: To evaluate the risk of root resorption, individual finite element models (FEMs) of extracted human maxillary first premolars were created, and the distribution of the hydrostatic pressure in the periodontal ligament (PDL) of these models was simulated. MATERIALS AND METHODS: A continuous lingual torque of 3 Nmm and 6 Nmm respectively was applied in vivo to the aforementioned teeth. After extraction, FEMs of these double-rooted teeth were created based on high-resolution microcomputed tomographics (micro CT, voxel size: 35 microns). This high volumetric resolution made the recognition of very small resorption lacunae possible. Scanning electron micrographs of the root surfaces were created as well. This enabled the investigation of advantages and disadvantages of the different imaging techniques from the viewpoint of the examination of root resorption. Using the FEMs, the same loading conditions as applied in vivo were simulated. RESULTS: The results of clinical examination and simulations were compared using the identical roots of the teeth. The regions that showed increased hydrostatic pressure (>0.0047 MPa) correlated well with the locations of root resorption for each tooth. Increased torque resulted in increased high-pressure areas and increased magnitudes of hydrostatic pressure, correlating with the experiments. CONCLUSION: If hydrostatic pressure exceeds typical human capillary blood pressure in the PDL, the risk of root resorption increases.

Root resorption on torqued human premolars shown by tartrate-resistant acid phosphatase histochemistry and transmission electron microscopy.

OBJECTIVE: To identify clastic cells on the root surfaces of torqued human premolars. MATERIALS AND METHODS: A continuous force of 600 cNmm was applied to upper first premolars in patients 13-16 years of age by using a precise biomechanical model with superelastic wires (NiTi-SE). The 28 teeth in 14 patients were divided into five groups (control [nonmoved], and moved for either 1, 2, 3, or 4 weeks) and processed for tartrate-resistant acid phosphatase (TRAP) histochemistry and transmission electron microscopy. RESULTS: Mononuclear TRAP-positive cells appeared at 2 weeks, where as large multinucleated TRAP-positive cells were numerous at 3 and 4 weeks. Ultrastructural examination revealed many clastic cells in contact with resorption lacunae. In addition, some cementoblast-like cells appeared secreting new cementum over previously resorbed lacunae. CONCLUSIONS: In general, resorption lacunae and the number of clastic cells, which increased with the duration of the applied force, were found on the cementum surface at the pressure areas. Some signs of cementum repair were also noticed, even with the maintenance of the level of the force.

Long-term effectiveness and treatment timing for Bionator therapy.

The aim of the present investigation was to provide information about the long-term effects and optimal timing for class-II treatment with the Bionator appliance. Lateral cephalograms of 23 class-II patients treated with the Bionator were analyzed at three time periods: T1, start of treatment; T2, end of Bionator therapy; and T3, long-term observation (after completion of growth). T3 includes a phase with fixed appliances. The treated sample was divided into two groups according to their skeletal maturity as evaluated by the cervical vertebral maturation (CVM) method. The early-treated group (13 subjects) initiated treatment before the peak in mandibular growth, which occurred after completion of Bionator therapy. The late-treated group (10 subjects) received Bionator treatment during the peak. The T1-T2, T2-T3, and T1-T3 changes in the treated groups were compared with changes in control groups of untreated class-II subjects by nonparametric statistics (P < .05). The findings of the present study on Bionator therapy followed by fixed appliances indicate that this treatment protocol is more effective and stable when it is performed during the pubertal growth spurt. Optimal timing to start treatment with the Bionator is when a concavity appears at the lower borders of the second and the third cervical vertebrae (CVMS II). In the long-term, the amount of significant supplementary elongation of the mandible in subjects treated during the pubertal peak is 5.1 mm more than in the controls, and it is associated with a backward direction of condylar growth. Significant increments in mandibular ramus height also were recorded.

Space management during dentition development: a case report / Supervisão do espaço durante o desenvolvimento da dentição: relato de caso clínico

This case report describes a significant follow-up of a patient who had ectopic eruption. A 10-year-old child presenting a lower right second premolar with an eruption deviation was passively corrected. The 11 years follow-up showed the tooth with good root length, closed apex and functionally active. For proper positioning of the permanent tooth, the developmental phases of dentition as well as its eruption sequence, symmetry, and chronology were early observed by the practitioner. This unusual long-term follow-up case showed that space management during dentition development and opportune diagnosis can avoid more complicated orthodontic treatments in some cases.

Este caso clínico descreve um significativo acompanhamento de uma paciente com erupção ectópica. A paciente, com 10 anos de idade, apresentava o segundo pré-molar inferior direito com desvio de erupção, que foi passivamente corrigido. O acompanhamento de 11 anos do caso mostrou o dente com bom comprimento de raiz, ápice fechado e funcionalmente ativo. Para o correto posicionamento do dente permanente, as fases de desenvolvimento da dentição, assim como a sequência de erupção, simetria e cronologia foram observadas desde o início pelo profissional. Este interessante caso com acompanhamento em longo prazo demonstrou que a supervisão de espaço durante desenvolvimento da dentição e o diagnóstico oportuno podem evitar tratamentos ortodônticos mais complicados em alguns casos.

Ultrastructural and histochemical examination of alveolar bone at the pressure areas of rat molars submitted to continuous orthodontic force.

It is usually believed that repair in alveolar bone during orthodontic movement occurs after decreasing of force. However, we have recently observed signs of repair in previously resorbed cementum from human teeth exposed to continuous forces. In order to test the hypothesis that bone resorption and deposition occur concomitantly at the pressure areas, a continuous 15 cN force was applied in a buccal direction to upper first molars from eight 2.5-month-old male Wistar rats for 3 d (n = 4) and 7 d (n = 4). As a control, two additional rats did not have their molars moved. Maxillae were fixed in 2% glutaraldehyde + 2.5% formaldehyde, under microwave irradiation, decalcified in ethylenediaminetetraacetic acid, and processed for transmission electron microscopy. Specimens from one rat from each group were processed for tartrate-resistant acid phosphatase (TRAP) histochemistry. At both the times studied, the alveolar bone surface at the pressure areas showed numerous TRAP-positive osteoclasts, which were apposed to resorption lacunae. In addition, osteoblasts with numerous synthesis organelles were present in the neighboring areas overlying an organic matrix. Thus, this study provides evidence that the application of continuous forces produces concomitant bone resorption and formation at the pressure areas in rat molars.

Estudo preliminar in vivo da magnitude de força gerada na expansão rápida da maxila (ERM) / An in vivo preliminary study of force magnitude generated in rapid maxillary expansion (RME)

A expansão rápida da maxila (ERM) sempre despertou grande interesse nos pesquisadores da área da Ortodontia e Ortopedia facial ao longo dos anos por ser um dos procedimentos mais empregados na especialidade. Além disso, as atresias maxilares desenvolvem-se de uma maneira precoce sem autocorreção espontânea. A magnitude de força expansiva e suas implicações durante o procedimento clínico de ERM permanecem questionáveis até hoje. O presente estudo tem como objetivo avaliar a magnitude e o comportamento da força expansiva durante a ERM nas fases das dentições mista e permanente jovem. Esta amostra inicial foi composta por 4 pacientes brasileiros, do gênero feminino, e que foram separados em dois grupos de acordo com suas fases de dentição: Grupo I, composto de dois pacientes com dentição mista e Grupo II composto de dois pacientes com dentição permanente jovem. O aparelho utilizado no estudo foi um disjuntor palatino do tipo McNamara. O protocolo de ativação foi de duas ativações diárias. Os resultados obtidos permitem concluir que o comportamento das forças expansivas ao longo do procedimento variou longitudinalmente, individualmente e entre os grupos experimentais. Observa-se ainda que a força máxima expansiva mensurada no Grupo I foi de 65N e no Grupo II de 78N.

Rapid maxillary expansion (RME) is a largely employed procedure and therefore it has always aroused great interest of researchers in the Orthodontic and facial Orthopedics fields. In addition, maxillary constrictions have an early development and are hardly self corrected. The aim of this preliminary study was to assess the magnitude and behavior of the expansive force during RME in mixed and young permanent dentition. The sample consisted of 4 Brazilian female patients, who were sorted in two groups: Group I, two patients with mixed dentition and Group II, two patients, with young permanent dentition. The appliance utilized in this study was a McNamara palatal distractor. The activation protocol included two daily activations. Results acquired allow for the conclusion that the behavior of expanding forces along the procedure has varied in longitudinal manner, individually and between the experimental groups. And they have also determined that the maximum expanding force measured in Group I was 65N, and in the Group II it was 78N.

Crescimento da base craniana nos diferentes tipos faciais nos relacionamentos maxilomandibulares ortopédicos de Classe I, II e III: parte 3 (crescimento médio de CF-Po) / Cranial base growth in different facial types in Class I, II and III orthopedic maxillomandibular relationship: part 3 (mean growth of CF-Po)

OBJETIVO: este estudo retrospectivo avaliou o crescimento médio de CF-Po nos diferentes tipos faciais nos relacionamentos maxilomandibulares ortopédicos de Classe I, II e III. METODOLOGIA: uma amostra aleatória de 300 pacientes brasileiros leucodermas (131 do gênero masculino, 169 do gênero feminino), com idade média inicial de 10 anos e 2 meses (dentadura mista) e final de 14 anos e 8 meses (segundos molares em oclusão) e tempo médio de observação de 4 anos e 5 meses, foi selecionada em uma clínica particular, em São Paulo, Brasil. Havia 118 pacientes Classe I, 151 Classe II e 31 Classe III. Todas as 600 radiografias cefalométricas laterais foram obtidas no mesmo aparelho de raios-x. As análises de Ricketts e Schwarz modificadas por Faltin foram usadas. A medida linear CF-Po foi feita manualmente pelo mesmo examinador em T1 e T2. Os relacionamentos foram estudados juntos e separadamente, considerando tipo facial e gênero. A análise de variância de ANOVA foi aplicada. RESULTADOS E CONCLUSÕES: o tipo facial retrovertido mostrou-se significativamente desfavorável à correção de Classe III mandibular no gênero masculino; com tendência desfavorável à Classe II mandibular e crescimento ântero-posterior favorável na Classe I. O neutrovertido mostrou-se significativamente favorável à correção de Classe III mandibular em ambos os gêneros; com tendência favorável à correção de Classe II mandibular e ao crescimento ântero-posterior na Classe I. O provertido mostrou-se significativamente desfavorável à correção de Classe III em ambos os gêneros e favorável na Classe II mandibular e com tendência favorável de crescimento ântero-posterior na Classe I, principalmente no gênero masculino.

AIM: This retrospective study assessed the cranial base growth and development in different facial types in Class I, II and III orthopedic maxillomandibular relationship. METHODS: A random sample of 300 Brazilian Caucasian patients (131 males, 169 females), with initial mean age of 10 years and 2 months (mixed dentition) and final mean age 14 years and 8 months (second molar in occlusion) and mean observation time of 4 years and 5 months, was selected at a private clinic in São Paulo. There were 118 Class I; 151 Class II and 31 Class III. All 600 lateral cephalometric radiographs were taken using the same x-rays equipment. Ricketts and Schwarz analyses modified by Faltin were used. The same examiner performed manually CF-Po linear measure in T1 and T2. All Classes were studied together and separately, considering facial type and gender. ANOVA variance analysis was carried out. RESULTS AND CONCLUSIONS: Retroversion facial type was significantly unfavorable to Class III correction in males; it showed unfavorable tendency to mandibular Class II correction and favorable anteroposterior growth tendency in Class I. Neutroversion was significantly favorable to mandibular Class III correction in both genders; it showed favorable tendency to mandibular Class II correction and favorable anteroposterior growth tendency to Class I. Proversion was significantly unfavorable and favorable to Class III and Class II correction in both genders, respectively; it showed favorable anteroposterior growth tendency to Class I mainly in males.

Crescimento da base craniana nos diferentes tipos faciais nos relacionamentos maxilomandibulares ortopédicos de Classe I, II e III: parte 2 (Crescimento médio de Ba-Na, CC-Na e CC-Ba) / Cranial base growth in different facial types in Class I, II and III orthopedic maxillomandibular relationship: part 2 (Mean growth of Ba-Na, CC-Na and CC-Ba)

OBJETIVO: este estudo retrospectivo avaliou o crescimento médio da base craniana nos diferentes tipos faciais e de relacionamentos maxilomandibulares ortopédicos.METODOLOGIA: uma amostra aleatória de 300 pacientes brasileiros leucodermas (131 do gênero masculino, 169 do gênero feminino), com idade média inicial de 10 anos e 2 meses (dentadura mista) e final de 14 anos e 8 meses (segundos molares em oclusão) e tempo médio de observação de 4 anos e 5 meses, foi selecionada em uma clínica particular, em São Paulo, Brasil. Havia 118 Classe I, 151 Classe II e 31 Classe III. Todas as 600 radiografias cefalométricas laterais foram obtidas no mesmo aparelho de raios-x. As análises de Ricketts e Schwarz modificadas por Faltin foram usadas. As medidas lineares (Ba-Na, CC-Na e CC-Ba) foram feitas manualmente pelo mesmo examinador em T1 e T2. Os relacionamentos foram estudados juntos e separadamente, considerando tipo facial e gênero. O teste t-pareado e ANOVA foram aplicados. RESULTADOS E CONCLUSÕES: o tipo facial retrovertido cresceu significantemente mais em CC-Na na Classe II, sendo a sua correção desfavorável no gênero feminino; com tendência favorável na Classe III e crescimento dentro do esperado na Classe I. O neutrovertido cresceu significantemente mais em CC-Na nas Classes I e II, sendo desfavorável na Classe II; com crescimento eqüitativo de CC-Na e CC-Ba na Classe III e levemente acima do esperado na Classe I. O provertido teve crescimento eqüitativo em todas as Classes, sendo significantemente favorável na Classe II mandibular; com tendência favorável na Classe III e crescimento médio acima do esperado na Classe I.

AIM: This retrospective study evaluated the cranial base mean growth in different facial types and orthopedic maxillomandibular relationship. METHODS: A random sample of 300 Brazilian Caucasian patients (131 males, 169 females), initial and final mean age (10 years 2 months-mixed dentition; 14 years 8 months-second molar occlusion) and mean observation time (4 years 5 months) was selected at a private clinic in São Paulo. There were 118 Class I; 151 Class II and 31 Class III. All 600 lateral cephalometric radiographs were taken using the same x-rays equipment. Ricketts and Schwarz analyses modified by Faltin were used. The same examiner performed manually the linear measures (Ba-Na, CC-Na and CC-Ba) in T1 and T2. All Classes were studied together and separately considering facial type and gender. Paired t-test and ANOVA were carried out. RESULTS AND CONCLUSIONS: The retroversion facial type grew significantly more in CC-Na in Class II, being unfavorable to Class II correction in females; with favorable tendency in Class III and an expecting growth in Class I. Neutroversion grew significantly more in CC-Na in Class I and II, being unfavorable in Class II; it had equitable growth of CC-Na and CC-Ba in Class III and it had considerably greater mean growth than the retroversion in Class I. Proversion had CC-Na and CC-Ba equitable growth in all Classes, it was significantly favorable in mandibular Class II; favorable tendency in mandibular Class III and it had the greatest mean growth in Class I.

Crescimento da base craniana nos diferentes tipos faciais nos relacionamentos maxilomandibulares ortopédicos de Classe I, II e III: parte 1 / Cranial base growth in different facial types in Class I, II and III orthopedic maxillomandibular relationship: part 1

OBJETIVO: este estudo retrospectivo avaliou o crescimento médio anual da base craniana nos diferentes tipos faciais nos relacionamentos maxilomandibulares ortopédicos de Classe I, II e III. METODOLOGIA: uma amostra aleatória de 300 pacientes brasileiros leucodermas (131 do gênero masculino, 169 do gênero feminino), com idade média inicial de 10 anos e 2 meses (dentadura mista) e final de 14 anos e 8 meses (segundos molares em oclusão) e tempo médio de observação de 4 anos e 5 meses, foi selecionada em uma clínica particular, em São Paulo, Brasil. Havia 118 Classe I, 151 Classe II e 31 Classe III. Todas as 600 radiografias cefalométricas laterais foram obtidas no mesmo aparelho de raios-x. As análises de Ricketts e Schwarz modificadas por Faltin foram usadas. As medidas lineares (Ba-Na, CC-Na, CC-Ba e CF-Po) foram feitas pelo mesmo examinadora em T1 e T2. Os tipos faciais e de relacionamentos foram estudados juntos com a amostragem total e subdividida por gêneros. Os testes de Levene e t de Student foram aplicados. RESULTADOS E CONCLUSÕES: os resultados confirmaram os valores de Langlade, porém mostraram dimorfismo sexual, com o gênero masculino crescendo significativamente mais que o feminino. Este estudo será de grande aplicação para a previsão de crescimento, prognóstico e o plano de tratamento de pacientes em crescimento.

AIM: to assess the cranial base annual mean growth in different facial types in Class I, II and III orthopedic maxillomandibular relationship. METHODS: a random sample of 300 Brazilian Caucasian patients (131 males, 169 females), with 10 years and 2 months (mixed dentition) initial mean age, 14 years and 8 months (second molar occlusion) final mean age and 4 years and 5 months mean observation time was selected at a private clinic in São Paulo - Brazil. There were 118 Class I, 151 Class II and 31 Class III. All 600 lateral cephalometric radiographs were taken using the same x-rays equipment. Ricketts and Schwarz analyses modified by Faltin Jr. were used. The same examiner performed the linear measures (Ba-Na, CC-Na, CC-Ba and CF-Po) in T1 and T2. All facial types and Classes were studied together with the total sample and separated by gender. Levene's test and Student's t-test were carried out. RESULTS AND CONCLUSION: the results confirmed Langlade's results, but showed sexual dimorphism with males growing significantly more than females. This study will be very useful for growth forecast, prognostic and treatment planning in growing patients.

Prevalência de más-oclusões em crianças na fase de dentição decídua e mista e sua associação com hábitos bucais deletérios / Prevalence of malocclusion in children during the deciduous and mixed dentition and its association with oral habits

Objetivos: Verificar a prevalência das más-oclusões de Angle e hábitos bucais deletérios, em crianças na fase de dentição decídua e mista atendidas na Clínica Infantil do Curso de Graduação em Odontologia da Universidade Paulista – UNIP, na cidade de São Paulo. Material e Método: A amostra constituiu-se de 289 crianças, com idades entre 3 e 11 anos, que estavam em tratamento de Odontopediatria e Ortodontia. Foram descritas as afinidades entre todos os fatores estudados e as diferentes más-oclusões. Para análise descritiva realizou-se uma divisão quanto à faixa etária e sexo, submetendo os resultados a uma análise estatística de variância e correlação dos fatores avaliados. Resultados: As más-oclusões de Angle apresentaram-se em média: 40,8% Classe I, 45,3% Classe II e 13,8% Classe III, sem variação significante segundo a faixa etária e o sexo. A prevalência de hábitos como agentes etiológicos mostrou percentual médio para onicofagia, seguindo-se para sucção de chupeta e sucção digital. As alterações funcionais apresentadas foram diversas, demonstrando uma incidência à alta de respiração bucal, ausência de selamento labial, deglutição atípica e fonação alterada. Conclusões: A amostra estudada apresentou uma alta prevalência das más oclusões de Angle e elevada incidência de hábitos e alterações funcionais, mostrando que é de fundamental importância o diagnóstico precoce para atuação preventiva e interceptativa na Clínica Infantil.

Aim: This study aimed to verify the Angle’s malocclusions prevalence and deleterious habits in children with deciduous and mixing dentition that were in treatment at the Clinic of the Dental Graduation Course on the Paulista University - UNIP, São Paulo city. Material and Method: The sample consisted of 289 children, with ages between 3 and 11 years old. In order to fulfill the analysis descriptive a division had been done per age range and sex, submitting the results to a statistics variance analysis and correlation of the factors evaluated. Results: The Angle’s malocclusions had presented 40.8% on average Class I, 45.3% Class II and 13.8% Class III, without significant variation according to age and sex. The prevalence of habits as etiological agents showed the average percentage for nail biting, following by pacifier and digital sucking. The presented functional alterations had been diverse, showing a high incidence of mouth breathing, lack of lip closure, atypical deglutition and speech changes. Conclusions: The studied sample presented a high prevalence of Angle’s malocclusions and high incidence of habits and functional changes, showing that it is important the early diagnosis for preventive and interceptative performance in Pedodontics Clinic.

El paciente infantil desde el punto de vista de la ortodoncia-ortopedia facial / The child patient from an orthodontic facial orthopedic point of view

En el presente artículo pretendemos de una forma sencilla y clara visualizar la importancia que existe de integrar dos especialidades muy afines, como son la Ortodoncia-Ortopedia Facial y la Odontopediatría; teniendo la obligación ambas de acompañar durante todo el crecimiento y desarrollo a nuestro paciente niño. Explicaremos lo importante de esta relación desde el diagnóstico, hasta llegar finalmente a determinar el momento ideal y que formas de tratamiento preventivo e interceptivo (dependiendo el caso)podemos llevar a cabo para lograr el éxito. Asimismo indicaremos todos los elementos necesarios a considerar para realizar una correcta evaluación y por consiguiente obtener un diagnóstico ortodóntico temprano; conocer que debemos tratar, y así determinar correctamente en que momento y que metodología a seguir.

In this article we try to point out in a clear and simple manner the importance of integrating two related specialties Facial Orthodontic-Orthopedic and Paediatric Dentistry, having both a common goal which is to accompany the growth and development of a child. We are going to explain the importance of this connection from the diagnosis to finally determine the ideal moment and the forms of preventive and interceptive treatment (according to each case) we can carry out to succeed. Also we will point out all the elements we need to consider to do a good evaluation so as to get an early orthodontic diagnosis and thus accurately determine the timing, the reason and the methodology to follow.