Bone stress and strain after use of a miniplate for molar protraction and uprighting: a 3-dimensional finite element analysis

The aim of this study was to use the finite element method to evaluate the distribution of stresses and strains on the local bone tissue adjacent to the miniplate used for anchorage of orthodontic forces. Methods: A 3-dimensional model composed of a hemimandible and teeth was constructed using dental computed tomographic images, in which we assembled a miniplate with fixation screws. The uprighting and mesial movements of the mandibular second molar that was anchored with the miniplate were simulated. The miniplate was loaded with horizontal forces of 2, 5, and 15 N. A moment of 11.77 N.mm was also applied. The stress and strain distributions were analyzed, and their correlations with the bone remodeling criteria and miniplate stability were assessed. Results: When orthodontic loads were applied, peak bone strain remained within the range of bone homeostasis (100-1500 mu m strain) with a balance between bone formation and resorption. The maximum deformation was found to be 1035 mu m strain with a force of 5 N. At a force of 15 N, bone resorption was observed in the region of the screws. Conclusions: We observed more stress concentration around the screws than in the cancellous bone. The levels of stress and strain increased when the force was increased but remained within physiologic levels. The anchorage system of miniplate and screws could withstand the orthodontic forces, which did not affect the stability of the miniplate.

Facial type measurements influence on transverse dimensions of normal occlusion arches

Objective – To correlate facial type measurements of Caucasian individuals with transverse dimensions of normal occlusion arches. Methods – Twenty-one pairs of dental models were selected according to the following inclusion criteria: presence of all permanent teeth from 1 st molar to 1 st molar; normal occlusion; no prosthetic crowns; no previous orthodontic treatment and 2 mm or less of crow- dings or spacings. The cephalometric measurements of lateral cephalometric X-ray of the same individuals were taken and tabulat ed. To evaluate the repetition of arch measurements, paired Student’s t-test and Pearson's correlation coefficient were used. The r elationship between the measurements was analysed by using the Pearson’s correlation. Results – The repetition of the measurements showed high correlation and no systematic error. In the comparison between the measurements, a moderate negative correlation was observed b et- ween facial axis angle and the measurements Upper and Lower 6-6, whereas a positive correlation was observed between dentition height and the latter. Conclusion – It was observed a negative correlation between facial axis angle and upper and lower inter-molar distance as well as a positive correlation between dentition height and upper and lower inter-molar distance.

Maxillary molar intrusion with zygomatic anchorage in open bite treatment: lateral and oblique cephalometric evaluation

Purpose We aimed to use lateral and oblique radiographs to evaluate dental and skeletal changes arising from maxillary molar intrusion with zygomatic anchorage in open bite patients. Methods We conducted a pilot study including nine patients (six females and three males; mean age, 18.7±5.1 years) with skeletal open bite treated with titanium miniplates for posterior dentoalveolar intrusion. Lateral and oblique (right and left, 45°) radiographs were obtained before (T1) and 6 months after intrusion (T2). A paired t test was used for statistical evaluation. Results The maxillary posterior teeth were intruded 2.03± 0.87 mm (p<0.01) with 450×g of force, which resulted in counterclockwise rotation of the mandible (1.57°, p=0.02) and clockwise rotation of the occlusal plane (4.27±2.66°, p=0.01). Anterior facial height decreased by a mean of 1.79±1.51 mm (p<0.01). No significant change in the palatal plane or in anteroposterior molar movement was observed. Conclusion The oblique radiograph at 45° was useful for the assessment of molar intrusion and anteroposterior displacement. The treatment of anterior open bite with skeletal anchorage provided intrusion of molars and counterclockwise rotation of the mandible, resulting in open bite closure.

Aparelho extrabucal como recurso auxiliar para alinhamento e nivelamento no tratamento orto cirúrgico de má oclusão classe III esquelética

When well indicated, the orthodontic surgical approach is the ideal treatment mean for Skeletal Class III adult patients. To improve facial esthetic results from orthognatic surgery, the leveling and alignment of maxillary dental arch must be achieved with minimal inclination and projection or even retro-inclination of anterior upper teeth. During a pre-surgical phase of 12 months, headgear bilateral force of 150 g/F was applied to the upper molars of a 22 years old male compliant patient with Class III skeletal malocclusion, to provide an upper teeth control of mesial tipping and projection during alignment and leveling. The ideal occlusal parameters required for surgical procedure were achieved without dental extractions permitting a total treatment period of 37 months. The outcomes remained stable over 3 years follow up after the removal of the appliance. The results indicate that, although headgear use depends greatly on patient compliance, when well indicated it is an interesting alternativetopromote dentaldecompensationon pre-surgical period, in order to allow surgical correction of skeletal Class III malocclusion.

Aparelho Herbst x osteotomia sagital mandibular bilateral no tratamento do padrão II, classe II, divisão 1 em adultos: relato de casos

Two treatment options are available for adult patients with skeletal Class II malocclusion caused by mandibular deficiency: combined mandibular advancement surgery and orthodontic treatment or mandibular advancement appliance. This study aimed to analyze the effects of two therapeutic modalities of Class II malocclusion treatment with mandibular deficiency. Two distinct individuals with Class II malocclusion division 1 and mandibular deficiency were treated after growth spurt. The first individual used the Herbst appliance as a therapeutic option and the second individual was treated with bilateral sagittal osteotomy. The cephalometric, occlusion and face results were evaluated for both individuals. Correction of Class II malocclusion was observed on both Herbst and surgery patients resulting on a normal occlusal relationship with normal overjet and overbite. Therefore it was concluded that Herbst appliance can be used to treat borderline skeletal Class II in adult patients.

Avaliação anteroposterior da posição da mandíbula em crianças dolicofaciais com má oclusão Classe II, divisão 1 de Angle

In this study, it is proposed to evaluate the anteroposterior position of mandible in children with Angle Class II, division 1 malocclusions, to compare two different methods of evaluating the jaw position and verifying the correlation between these two methods. We selected 26 Brazilian children with vertical growth pattern and Angle Class II, division 1 malocclusions, aged between 7 years and 8 months to 9 years and 6 months. The evaluation of the anteroposterior position of the mandible was performed with the use of lateral cephalograms by cephalometric angular SNB and linear Pog-Nperp. Based on the results obtained, it was concluded that the SNB identified more children with mandibular retrusion than Pog-Nperp; the increased tip of the SN plane may have decreased values of SNB; Pog-Nperp minimizes the possibility of error in the anteroposterior position of the mandible, since it eliminates the variable tip of the anterior skull base (SN plane); none of the cephalometric measurements used are able to eliminate the influence of the nasion point in the anterior-posterior and vertical position; correlation between SNB and Pog-Nperp is very low.

Avaliação cefalométrica das alterações do perfil facial naturais e induzidas pelos aparelhos de Herbst e Bionator no tratamento da má oclusão de classe II, divisão 1ª

The aim of this study was to evaluate the facial profile changes due to natural growth and induced by Herbst appliance and Bionator in the treatment of Class II, division 1 malocclusion. In order to do that, we used a sample of 90 lateral radiographs of 45 individuals in pre-pubertal stage, divided up in two experimental groups and one control. The first group, composed of 15 brazilian individuals, with initial mean age of 9.4 years, was treated with the Herbst appliance for a period of seven months. The second experimental group consisting of 15 brazilian individuals, initial mean age of 9.9 years has gone through bionator therapy for an average period of 21 months. The control group of 15 individuals, who were not treated orthodontically, comes up from the Burlington Growth Centre, University of Toronto, Canada. The intragroup comparison was performed using the Student t test and intergroup comparisons by ANOVA complemented by the Bonferroni test. The results have shown that only the group treated with the Herbst appliance presented significant changes in facial profile with improvement of its convexity and lower lip protrusion.

Avaliação do índice de Litle em indivíduos que utilizaram o aparelho funcional T4K

The study aimed to assess the degree of dental crowding correction on the lower anterior region of patients treated with T4k functional appliance using Little’s irregularity index. Twenty caucasian patients of both gender (10 female and 10 male) were selected. They featured malocclusion Class I and II in mixed dentition, with chronological age between 5.7 and 11 years. The treatment lasted from 1 year and 11 months up to 3 years and 11 months. Lower anterior crowding was measured using Little’s irregularity index. Measurements were obtained on study models achieved before and after functional orthopedic therapy, using a digital caliper in millimeters and placed parallel to the occlusal plane. Overjet and overbite measurements were also performed using a caliper. Results demonstrated that the therapy provided significant decrease in overjet (average = 1.55 mm) and also in the irregularity index (average = 1.23 mm). There was a nonsignificant raise in overbite. There was no relation between the studied variables and the treatment period or even with the patient’s age in the beginning of the therapy. The treatment with T4k resulted on reduction and improvement of dental crowding.

Efeitos do aparelho de Herbst no tratamento proecoce da má oclusão classe II de Angle

Due to its high prevalence in general population, Angle Class II malocclusion has been widely studied by several authors, as well as the methods for its treatment. Among the possible treatment methods stands out the Herbst appliance. Reintroduced more than three decades ago in the orthodontics community, it became the most utilized appliance because it does not require patient compliance, and provides continued action through bilateral telescopic tubes. The objective of the present article was to demonstrate the early treatment of Class II Division 1 malocclusion with mandibular retrusion using Herbst appliance.

Eficiência do aparelho Herbst bandado na correção da Classe II divisão 1 -relato de caso

The current reports the case of a young patient with malocclusion Class II division 1 on permanent dentition treated in two stages, rthopedics and orthodontics, respectively. At first, the banded Herbst appliance was used duringa 7 months period, followed by a T4K appliance, Trainer for Kids used as retention, and on the second stage the corrective Orthodontics was performed. The results showed the acquirement of a Class I dental relationship, which was kept stable, with excellent intercuspation, even after 5 years of the removal of the Herbst appliance, as well as the correction of the overjet and the reduction of the facial profile convexity. It can be concluded that the Herbst appliance was very efficient in correcting the Class II malocclusion, long term, also providing a very favorable effect on the facial profile.

Estudo em telerradiografia em norma de 45º no tratamento da classe II com aparelho de Herbst

The aim of this retrospective study was to evaluate mandibular and maxillary changes induced by the use of Herbst applianceand by natural growth through oblique cephalometric radiographs in children with Class II division 1 malocclusion with mandibular retrusion. A sample of 49 individuals with age ranging from 8 to 10 years old (before growth peak) with Class II division 1, were into two groups: Herbst treated group (n=24) and control group (n=25). Both groups were paired for gender and chronological age. Statistical analysis was performed through Student’s t test. The Herbst appliance promoted the Class II correction in a 7 months period by mesialization of lower permanent first molars and distalization of upper permanent first molars. The Herbst appliance had no influence over the mandibular structure or the mandibular length. It was concluded that early treatment with Herbst appliance corrected the Class II malocclusion by means of dentoalveolar changes.

Fechamento de diastema anterior: associação de procedimentos ortodôntico e restaurador

Several aspects beyond the restorative phase itself such as orthodontic movement and periodontal treatment must be considered in cases of closure of diastemas. In such cases, a multidisciplinary approach is essential. As patients during orthodontic treatment may show high risk of developing dental caries and periodontal disease, inflammation of the gingival tissue is a common finding. For this reason, a preliminary basic periodontal treatment is critical to the success of restorative procedure. In addition, postoperative care and instruction in phonetics, oral hygiene and periodic control must be considered by professionals and patients. Thus, this paper demonstrates through a case report, pre and postoperative issues that should be considered during the closure of diastemas using a layering technique with resin composites

Infra-oclusão de molares decíduos: diagnóstico e tratamento

Infraocclusion of deciduous molars is defined by total or partial periodontal ligament absence and characterized by the cementum or dentin anatomical fusion with alveolar bone. This study aims to report an ankylosis clinical case, the implications and treatments management options in the deciduos dentition.

Reaproveitamento imediato da ação expansora em um caso de expansão rápida da maxila assistida cirurgicamente

Immediate reutilization of the expanding action in a case of rapid maxillary expansion surgically assisted. The orthopedic rapid maxillary expansion (RME) and rapid maxillary expansion surgically assisted (RMESA) are conducted with the aim of giving an appropriate jaw, capable of providing a normal occlusion. In extreme cases, where there is a severe atresia, it is necessary to perform an expansion beyond that allowed by the expander, followed by another conventional device or a butterfly expander, when the atresia is in the anterior maxillary region. In this situation, there are two options: wait about 90 days to allow intermaxillary suture restructuring and perform a new RME / RMESA or proceed immediately to the expansion process. Considering the biological cost, financial and clinical time, the procedure of reusing the immediate expander action becomes the technique of choice in these cases, been the operational procedure performed simplified and in just four steps. This work will show a case report where, after accomplishing the RMESA was observed that even after changing the shape of the maxillary arch, the severity of atresia could not be corrected, especially in the anterior region, and more expansion was needed. Aiming to correct the atresia in the anterior maxilla, the technique used was to reuse the immediate expander action through the change of an intraoral screw expander for a conventional butterfly type screw expander.