Assessing bone thickness in the infrazygomatic crest area aiming the orthodontic miniplates positioning: a tomographic study.

INTRODUCTION:: Due to the increasing use of miniplates for anchorage purposes in orthodontics, it is very important to know more about infrazigomatic crest anatomy (thickness), in adult patients. OBJECTIVES:: Evaluate the infrazygomatic crest region thickness, in adult (male and female) patients. METHODS:: Cone-beam computerized tomography (CBCT) images from 40 patients were used to assess cross-sectional measurements of the infrazygomatic crest region. Measurement 1 considered thickness 2 mm above the distobuccal root of the permanent maxillary first molar, while measurement 2 was taken 2 mm above the first measurement. RESULTS:: The mean thickness of the infrazygomatic crest in males was 3.55 mm for measurement 1 and 2.84 mm for measurement 2, while in females these were 2.37 mm and 2.24 mm, respectively. CONCLUSION:: The authors concluded that the overall mean thickness of the infrazygomatic crest was 2.49 mm with respect to measurement 1, and 2.29 mm for measurement 2, with no statistically significant differences between gender.

Assessing bone thickness in the infrazygomatic crest area aiming the orthodontic miniplates positioning: a tomographic study

ABSTRACT Introduction: Due to the increasing use of miniplates for anchorage purposes in orthodontics, it is very important to know more about infrazigomatic crest anatomy (thickness), in adult patients. Objectives: Evaluate the infrazygomatic crest region thickness, in adult (male and female) patients. Methods: Cone-beam computerized tomography (CBCT) images from 40 patients were used to assess cross-sectional measurements of the infrazygomatic crest region. Measurement 1 considered thickness 2 mm above the distobuccal root of the permanent maxillary first molar, while measurement 2 was taken 2 mm above the first measurement. Results: The mean thickness of the infrazygomatic crest in males was 3.55 mm for measurement 1 and 2.84 mm for measurement 2, while in females these were 2.37 mm and 2.24 mm, respectively. Conclusion: The authors concluded that the overall mean thickness of the infrazygomatic crest was 2.49 mm with respect to measurement 1, and 2.29 mm for measurement 2, with no statistically significant differences between gender.

RESUMO Introdução: devido ao aumento do uso de miniplacas para ancoragem em Ortodontia, torna-se de fundamental importância compreender melhor a anatomia da crista infrazigomática (espessura) em pacientes adultos. Objetivos: avaliar a espessura da crista infrazigomática em pacientes adultos (sexos feminino e masculino). Métodos: foram utilizadas tomografias computadorizadas de feixe cônico (TCFC) de 40 pacientes, para avaliar medidas da região da crista infrazigomática, no sentido transversal. A Medida 1 verificou a espessura mm acima da raiz distovestibular do primeiro molar permanente superior, enquanto a Medida 2 foi realizada 2 mm acima da primeira medida. Resultados: a espessura média da crista infrazigomática encontrada no sexo masculino foi de 3,55 mm para a Medida 1 e de 2,84 mm para a Medida 2, e no sexo feminino foi de 2,37 mm e de 2,24 mm, respectivamente. Conclusão: os autores puderam constatar que a espessura média da crista infrazigomática foi de 2,49 mm para a Medida 1, e de 2,29 mm para a Medida 2, sem diferença estatisticamente significativa entre os sexos.

Impact of metal and ceramic fixed orthodontic appliances on judgments of beauty and other face-related attributes.

INTRODUCTION: Physical attributes, behavior, and personal ornaments exert a direct influence on how a person's beauty and personality are judged. The aim of this study was to investigate how people who wear a fixed orthodontic appliance see themselves and are seen by others in social settings. METHODS: A total of 60 adults evaluated their own smiling faces in 3 different scenarios: without a fixed orthodontic appliance, wearing a metal fixed orthodontic appliance, and wearing an esthetic fixed orthodontic appliance. Furthermore, 15 adult raters randomly assessed the same faces in standardized front-view facial photographs. Both the subjects and the raters answered a questionnaire in which they evaluated criteria on a numbered scale ranging from 0 to 10. The models judged their own beauty, and the raters assigned scores to beauty, age, intelligence, ridiculousness, extroversion, and success. RESULTS: The self-evaluations showed decreased beauty scores (P <0.0001) when a fixed orthodontic appliance, especially a metal one, was being worn. There was no statistically significant difference between the 3 situations in the 6 criteria analyzed. CONCLUSIONS: A fixed orthodontic appliance did not affect how personal attributes are assessed. However, fixed orthodontic appliances apparently changed the subjects' self-perceptions when they looked in the mirror.

Application of two segmentation protocols during the processing of virtual images in rapid prototyping: ex vivo study with human dry mandibles.

OBJECTIVES: The aim of this study was to evaluate the accuracy of virtual three-dimensional (3D) reconstructions of human dry mandibles, produced from two segmentation protocols ("outline only" and "all-boundary lines"). MATERIALS AND METHODS: Twenty virtual three-dimensional (3D) images were built from computed tomography exam (CT) of 10 dry mandibles, in which linear measurements between anatomical landmarks were obtained and compared to an error probability of 5 %. RESULTS: The results showed no statistically significant difference among the dry mandibles and the virtual 3D reconstructions produced from segmentation protocols tested (p = 0,24). CONCLUSIONS: During the designing of a virtual 3D reconstruction, both "outline only" and "all-boundary lines" segmentation protocols can be used. CLINICAL RELEVANCE: Virtual processing of CT images is the most complex stage during the manufacture of the biomodel. Establishing a better protocol during this phase allows the construction of a biomodel with characteristics that are closer to the original anatomical structures. This is essential to ensure a correct preoperative planning and a suitable treatment.