Individual variation of the distance between nasion and Frankfort horizontal plane-an error factor of facebow in semi-adjustable articulators.

STATEMENT OF PROBLEM: Semi-adjustable articulators use an average axis facebow with a nasion relator at a fixed distance of 22 mm or 23 mm from the orbitale anterior reference point to locate the axis orbital plane, which is a major factor in measuring the sagittal condylar inclination. Lateral cephalometric radiograph allows the measurement of the distance between the nasion and Frankfort horizontal plane, which has shown great variability among patients. PURPOSE: Measure and describe individual variation of the distance between nasion and Frankfort horizontal plane, and error factor of facebow in semi-adjustable articulators, in order to assess the importance of an accurate transfer of the axis orbital plane of the patient to the articulator. MATERIAL AND METHODS: This cross-sectional analytic clinical study used 637 lateral cephalometric radiographs from the database of 2 private clinics in Santiago de Chile. The distance between the nasion and Frankfort horizontal plane was measured. Then, a correction of -7.1 mm was applied to determine the distance between N and the axis orbital plane, and this corrected distance was analyzed and compared with the one used by Panadent and Whip Mix articulators. In 150 cephalometric radiographs, the measurements were classified according to facial biotype and skeletal class. ANOVA Bonferroni test was applied to recognize how the N to FHP measurements behave according to biotype and skeletal class (P ≤ .05). RESULTS: The average corrected distance from nasion to axis orbital plane in the present study was 24.7 mm, 2.7 mm higher than the distance used by Panadent articulator and 1.7 mm higher than the distance used by Whip Mix articulator. No statistically significant differences were found among biotypes or the different skeletal classes. CONCLUSIONS: For the studied population, a fixed-value nasion relator is a factor that introduces error.

Aporte de los adhesivos dentales en la rehabilitación del desdentado. Revisión narrativa / Contribution of dental adhesives in the rehabilitation of the edentulous patient. Narrative review

RESUMEN: El uso de medios auxiliares como es el caso de los adhesivos dentales permitirá que la adhesión entre la prótesis y la mucosa sea mejor y se logre una mejor retención, estabilidad y eficiencia masticatoria. Se realizó una búsqueda en internet en las siguientes bases de datos, Pubmed, EBSCO, BEIC, Cochrane y Epistemonikos. Para la búsqueda electrónica se utilizaron las palabras "denture adhesive", "dental adhesive", "complete denture wearers", "retention", "support", "stability", "masticatory performance", "Candida albicans" y "quality of life" relacionadas con el operador booleano AND. Al aplicar los criterios de inclusión y exclusión terminando con 14 artículos. Finalmente, quedaron 5 ensayos clínicos aleatorizados, 3 ensayos clínicos no aleatorizados, 2 estudios observacionales de cohorte prospectivos, 3 artículos in vivo y 1 estudio in vitro. Los adhesivos dentales han demostrado un mejoramiento en la retención, adhesión, estabilidad y eficiencia masticatoria en los portadores de prótesis totales, independiente de su presentación, sea en forma de polvo, crema, tiras o almohadillas. Por medio de su uso, se ha demostrado que los portadores de prótesis totales han podido mejorar su calidad de vida, tanto en la seguridad del manejo de su aparato protésico como en el aspecto nutricional, pues permite que se alimenten de mejor forma, esto incluso es posible observar cuando se prescriben en aquellos pacientes con prótesis recién instaladas.

ABSTRACT: Introduction: When performing the oral rehabilitation of edentulous patients using total prostheses, in some cases, a slight maladjustment of the prosthetic device within the oral cavity can compromise the chewing, swallowing and phonation functions. With the use of ancillary means such as dental adhesives, which allow the adhesion between the prosthesis and the mucosa, a better retention, stability and masticatory efficiency is achieved, and therefore, an increase in the quality of life of the patient. Main objective: To perform a narrative review to describe the contribution of the use of dental adhesives in patients with total dentures. Method: We searched the following databases, Pubmed, EBSCO, BEIC, Cochrane and Epistemonikos. The words "denture adhesive", "dental adhesive", "complete denture wearers", "retention", "support", "stability", "masticatory performance", "Candida albicans" and "quality of life " were searched electronically with the Boolean operator AND. Results: As a result, 394 articles were obtained, 85 of which were selected by title, of which the repeated articles were eliminated, leaving 32; then, the abstracts were read, leaving 22 articles. The remaining articles were read completely, the inclusion and exclusion criteria were applied, ending with 14 articles. Finally, 5 randomized clinical trials, 3 non-randomized clinical trials, 2 prospective cohort observational studies, 3 in vivo articles and 1 in vitro study were included. Conclusion: Dental adhesives have showed an increase in retention, stability, ability and masticatory efficiency in patients with total prostheses, regardless of their presentation. Through its use, it has been demonstrated that total denture wearers have been able to improve their quality of life, even patients with recently installed prostheses.

Biomateriales en levantamiento de seno maxilar para implantes dentales / Biomaterials in maxillary sinus lift for dental implants

RESUMEN: Objetivos El objetivo principal es describir las técnicas y condiciones en que se usan los diferentes biomateriales para los procedimientos de aumento del seno maxilar en implantes oseointegrados inmediatos o diferidos. Método Se realizó una búsqueda electrónica de textos completos desde el año 2010 hasta el 15 de agosto del 2014, y que respondieran la pregunta de investigación, utilizando diferentes buscadores y una manual en las revistas científicas de periodoncia. Se determinó el nivel de evidencia, calidad de reporte, sesgos de la literatura analizada y aspectos éticos. Resultados Se seleccionaron 17 estudios, 4 revisiones sistemáticas y 13 ensayos clínicos aleatorizados. Diez estudios comparaban los diferentes biomateriales disponibles entre sí, y no encontraron diferencias estadísticamente significativas en la nueva formación ósea. Un estudio examinaba la opción de no utilizar un biomaterial en el aumento de senos maxilares. Seis estudios indicaban que el uso de biomateriales adicionales no era significativo. Tres estudios concluyeron que no existían diferencias significativas entre uno o 2 tiempos quirúrgicos para realizar los procedimientos. Tres estudios comparaban la técnica quirúrgica de ventana lateral con la técnica indirecta, sin encontrar diferencias estadísticamente significativas, pero sí se asocia a un menor número de complicaciones a la técnica indirecta, especialmente al estar acompañada de la instalación de implantes cortos. Conclusiones No se describen diferencias entre los diferentes biomateriales utilizados en procedimientos de aumento de senos maxilares. El uso de biomateriales adicionales pareciera no ofrecer beneficios medibles al tratamiento. La técnica quirúrgica indirecta puede ser asociada a un menor número de complicaciones. Son necesarios más estudios de ensayos clínicos aleatorizados, con tamaños de muestra mayores, variables controladas y seguimientos a largo plazo para establecer conclusiones.

ABSTRACT: Objectives The main objective is to describe the techniques and conditions in which the various biomaterials are used for sinus augmentation procedures for immediate or delayed osseointegrated implants. Method An electronic search was conducted looking for papers published from 2010 to 15 August 2014 to answer the research question. Several search engines were used as well as a manual on scientific journals of periodontics. The level of evidence, quality reporting, biases of the analysed literature, and ethical aspects were determined. Results A total of 17 studies were selected, of which 4 were systematic reviews, and 13 were randomised trials. Ten different trials compared the available biomaterials with each other, and found no statistically significant differences in new bone formation. One study examined the option of not using biomaterials in the procedures. Six studies indicated that the use of additional biomaterials was not significant. Three studies concluded that there were no significant differences between 1 and 2 surgical times. Three studies compared the surgical technique of lateral window with the indirect technique, with no statistically significant differences, but the indirect technique was associated with fewer complications, especially when accompanied by the installation of short implants. Conclusions No differences between different biomaterials used in augmentation procedures for maxillary sinuses were described. The use of additional biomaterials does not seem to offer measurable benefits to the treatment. The indirect surgical technique may be associated with fewer complications. Further studies of randomised clinical trials, with larger sample sizes, controlled variables, and long term monitoring are needed to draw stronger conclusions.

Functional compartmentalization of the human superficial masseter muscle.

Some muscles have demonstrated a differential recruitment of their motor units in relation to their location and the nature of the motor task performed; this involves functional compartmentalization. There is little evidence that demonstrates the presence of a compartmentalization of the superficial masseter muscle during biting. The aim of this study was to describe the topographic distribution of the activity of the superficial masseter (SM) muscle's motor units using high-density surface electromyography (EMGs) at different bite force levels. Twenty healthy natural dentate participants (men: 4; women: 16; age 20±2 years; mass: 60±12 kg, height: 163±7 cm) were selected from 316 volunteers and included in this study. Using a gnathodynamometer, bites from 20 to 100% maximum voluntary bite force (MVBF) were randomly requested. Using a two-dimensional grid (four columns, six electrodes) located on the dominant SM, EMGs in the anterior, middle-anterior, middle-posterior and posterior portions were simultaneously recorded. In bite ranges from 20 to 60% MVBF, the EMG activity was higher in the anterior than in the posterior portion (p-value = 0.001).The center of mass of the EMG activity was displaced towards the posterior part when bite force increased (p-value = 0.001). The topographic distribution of EMGs was more homogeneous at high levels of MVBF (p-value = 0.001). The results of this study show that the superficial masseter is organized into three functional compartments: an anterior, a middle and a posterior compartment. However, this compartmentalization is only seen at low levels of bite force (20-60% MVBF).