Accuracy between virtual surgical planning and actual outcomes in orthognathic surgery by iterative closest point algorithm and color maps: A retrospective cohort study.

BACKGROUND: To evaluate the accuracy between actual outcomes and virtual surgical planning (VSP) in orthognathic surgery regarding the use of three-dimensional (3D) surface models for registration using iterative closest point (ICP) algorithm and generated color maps. MATERIAL AND METHODS: Construction of planning and postoperative 3D models in STL files format (M0 and M1, respectively) from CBCT of 25 subjects who had been submitted to bimaxillary orthognathic surgery was performed. M0 and M1 were sent to Geomagic software in semi-automatic alignment surface mesh order of M0 and M1 for registration using ICP algorithm to calculate mean deviation (MD, MD+, MD-, SD) and root mean square (RMS - 3D Error). Color maps were generated to assess qualitative congruence between M0 and M1. From deviation analysis, 3D Error was defined as accuracy measurement. To assess the reproducibility, the workflow was performed by two evaluators multiple times. t-tests were used to assess whether all means of MD, MD+, MD-, SD and 3D Error values would be ≤ - 2 mm and ≥ 2 mm. RESULTS: High intra and inter evaluators correlation were found, supporting the reproducibility of the workflow. t-tests proved that all MDs and 3D Error values were > - 2 mm and < 2 mm. CONCLUSIONS: 3D error mean was within the standards of clinical success lower than 2 mm. ICP algorithm provided a reproducible method of alignment between 3D models and generated color maps to evaluate 3D congruence but did not answer all methodological parameters regarding the assessment of accuracy in orthognathic surgery.

Nasal deformity in subjects with class III facial deformities / Deformidad nasal en sujetos con deformidad facial clase III

Dentofacial deformities present some shades and variations that determine the inclusion of different anatomical components as part of the disease; the aim of this study was to ascertain the nasal characteristics in patients with a Class III dentofacial deformity. A descriptive study was conducted on 20 patients diagnosed with a Class III facial deformity and a surgical indication; frontal and lateral as well as CT images were taken to analyze variables of nasal morphology and deformities associated with the nasal bridge, tip and septum. The results showed that the nasal angles are outside normal parameters and that the basal width of the nose is approximately 3 mm smaller than the intercanthal width; 45% of the subjects have lateral deviations, 50% bridge deformity and 80% septum deviation. It is concluded that there are nasal deformities in subjects with a Class III facial deformity and that this component must be carefully evaluated in the preoperative stage.

Las deformidades dentofaciales presentan algunos matices y variaciones que determinan la inclusión de diferentes componentes anatómicos dentro de la enfermedad; el objetivo de esta investigación es conocer las características de la nariz en pacientes con deformidad dentofacial de clase III. Se desarrollo un estudio descriptivo en 20 pacientes con diagnóstico de deformidad facial declase III e indicación quirúrgica; se estudiaron análisis fotográficos frontales y laterales así como tomografías computadorizadas para analizar variables de morfología nasal y deformidades asociadas al puente nasal, punta nasal y septo nasal. Los resultados demostraron que los ángulos nasales se encuentran fuera de los parámetros de normalidad y que el ancho basal de la nariz es aproximadamente 3 mm menor que el ancho intercantal; el 45% de los sujetos presentó desviación lateral, 50% deformidad del puente nasal y el 80% desvío de septo nasal. Se concluye que existen deformidades nasales en sujetos con deformidad facial de clase III y que este componente debe ser evaluado criteriosamente en la etapa preoperatoria.

Segmental osteotomy with interpositional bone grafting in the posterior maxillary region.

Tooth loss is followed by a natural bone resorption process that often leads to defects in the alveolar ridge, making the installation of dental implants unfeasible. Correction of such bone defects, especially loss of height of the ridge or associated loss of thickness, is a great challenge to dental surgeons. The technique of segmental osteotomy accompanied by interpositional bone grafting has been shown to be a viable option for addressing the problem. This report describes a successful application of the technique in the treatment of vertical dimension deficiency in the posterior maxillary region. Four months after graft surgery, 3 implants were successfully placed in accordance with the original reverse planning.

Análisis microestructural de cinco sistemas de implantes de titanio comercialmente puro / Microstructural analysis of five commercially pure titanium implant systems

Hoy en día existe un gran número de empresas fabricantes de implantes así como diferentes tipos de implantes, lo que ha llevado a la diversificación en las técnicas de producción, no siempre asociados a una mejor calidad. El objetivo de este estudio fue identificar y tipificar cinco implantes de titanio comercialmente puro. Se utilizó un estudio descriptivo, doble ciego, para estudiar 15 muestras de implantes de 5 empresas comerciales. Cada implante fue removido de su transporte manteniendo sus características originales. Cada grupo fue de cinco implantes, nombrados con las letras A, B, C, D y E. el análisis incluyó metalografia, microscopia electrónica con sistema de microanálisis (SEM-EDS) y finalmente, un analizador de imágenes. Implamed® y Master Screw® mostraron granos de menor tamaño. En microfotografías ,todos exhibieron picos de titanio, carbono y oxígeno. Implamed® mostró también acero, sodio, magnesio, silicona, potasio e inclusiones de calcio. Todas las muestras mostraron buena finalización. Las variaciones observadas no serían suficientes para interferir en el proceso de oseointegración, no obstante las inclusiones de metal deben ser estudiadas detalladamente en sus efectos a largo plazo (AU)

Nowadays there is a great number of manufacturers and types of implants which has led to several techniques in their production, not always associated with better quality. The aim of this research was identify and typify five commercially pure titanium implant systems. A double-blind, descriptive trial was used with the selection of 15 samples from 5 different manufacturers. Each implant was removed from its package keeping its original characteristics. Five implant groups of 3 elements each were formed and named A, B, C, D, and E. The analyses included metallography, scanning electron microscopy with a microanalysis system (SEM-EDS) and, finally, an image analyzer. Implamed® and Master Screw®showed smaller grain sizes. In micrographies, they all showed peaks of titanium, carbon, and oxygen. Implamed® showed iron, sodium, magnesium, silicon, potassium, and calcium inclusions. All samples showed good finishing. Variations observed would not be enough to interfere with osseointegration but metal inclusions should be studied in greater detail in order to assess its effects in the long run (AU)

Análisis fotoelástico descriptivo de dos diferentes diseños de implantes endoóseos sometidos a carga decompresión vertical / Descriptive photoelastical analysis of two different dental implants design submitted to vertical compression load

El objetivo de este estudio fue analizar la distribución de las tensiones generadas en los modelos fotoelásticos posterior a la aplicación de cargas verticales a 7,5 N, en dos diferentes diseños de implantes endoóseos. Fueron seleccionados 2 implantes con diferentes configuraciones: Implante(Máster Conect Cônico® 4,13×13 mm) e Implante (Titamax Ti Medula® 3,75×13 mm). Para el análisis de la distribución de tensiones fueron confeccionados 2 modelos en resinas fotoelástica con dimensiones de 40×10 mm de base y 30 mm de altura. Cada implante posicionado en los modelos recibieron carga vertical a 7,5 N, siendo posible visualizar las franjas isocromáticas generadas en los modelos, a través del polariscopio. El implante Máster Conect Cônico® con hexágono interno largo, porción cervical pulida, tope de las roscas redondeadas, pasos de las roscas continuas, distancia entre estas de 0,5 décimas de milímetros, espirales angulados y ápice cónico presento concentración de las tensiones en la región apical. El implante cilíndrico, Titamax Ti Medula®, con hexágono externo, porción cervical pulida, con tope de las roscas en forma de v, paso de roscacontinuo, con distancia entre las roscas de 0.5 décimas de milímetros, espirales angulados y ápicere dondeado presento distribución de las tensiones en la región apical medio y cervical del implante. Basado en los resultados de este estudio puede concluirse que: el implante de configuración cónica concentró las tensiones en región apical, siendo que el implante de configuración cilíndrica concentro las tensiones en la región apical medio y cervical del implante (AU)

The objective of this study was to analyze the subsequent tensions distribution generated in the photoelastic models after application 7.5 N vertical loads, in two different dental implant designs. It were selected two different configuration implants, being one conic (Másters Conect Cônico®4.13×13 mm) and the other cylindrical (Titamax Ti Medula® 3.75×13 mm). For the analysis of the tensions distribution it were made two photoelastic resin models with dimensions of 40×10 mm of base and 30 mm of height. Each implant was positioned in the model and received vertical loads to7,5 N, being possible to visualize the isochromatic strips generated in it, through the polariscope. The Másters Conect Cônico® implants, that have long internal hexagon, polished cervical portion, top of spirals rounded, continuous passage of the spirals, distances between these of 0.5 tenth of millimeters, angled spirals and conical apex, presented the concentration of the tensions in the apical region. The cylindrical implants (Titamax Ti Medula®) with external hexagon, polished cervical portion, with top of the spirals in form of a “v”, continuous passage of spiral, with distance between the spirals of 0,5 tenth of millimeters, angled spirals and rounded apex, presented the distribution of the tensions on apical and cervical regions of the implants. Based on the results of this study it is possible to conclude that: the conical implants configuration concentrated the tensions in apicalregion, being the cylindrical configuration tensions concentrated on the apical and cervical region of the implants (AU)