Evaluation of expansion forces of five pure bone-borne maxillary expander designs anchored with orthodontic mini-implants: An in vitro study.

AIM: This in vitro study investigates the limit of expansion forces and torque wrench forces developed by five skeletal bone expander designs (MICRO 2/4 expanders™) for clinical application. MATERIAL AND METHODS: A total of 30 skeletal expanders were placed in artificial bone blocks and mechanically tested, simulating maxillary expansion. Differences in jackscrew (Dentaurum™ [D], Superscrew™ [S] and Powerscrew™ [P]), number of orthodontic mini-implants (OMIs; two or four) and their placement inclinations (parallel 0° or 10° inclination) form five designs (D4/10°, S4/0°, S4/10°, P4/10° and P2/10°). Expansion forces and torque wrench values were registered, and radiographs were made initially and after 4 mm of expansion. Stress-strain curves were obtained after successive activations and the statistical analysis was performed as appropriate. RESULTS: Plastic deformations in the OMIs and jackscrew occurred around the activation numbers 11-13, with torque wrench values in the range of 500-700 cN. The maximum expansion forces in expanders with four OMIs varied from 93.0 (D4/10°) to 166.6 N (P4/10°) whereas two OMI expanders (P2/10°) registered forces of 79.4 N. Radiographs revealed during loads bending forces (S4/00°, S4/10°) with jackscrew and OMIs deformation in a convex shape, and shear forces (P4/10°, P2/10°) demonstrated only OMIs deformation in a concave shape, providing 15% more expansive force. The jackscrew D4/10° did not have any deformation, but its wire key did not allow reliable activations from activation number 10 and compared to S4/10° and P4/10°, these expanders provided greater expansion forces (P = 0.000 and P = 0.032, respectively). CONCLUSION: The different results obtained in stability and expansion forces indicate that if the activations are carried out under extreme conditions, they may have clinical importance with deformations and non-working expansion mechanics. Jackscrew designs play an important role in expansive forces and expander stability. Torque wrench values can be used clinically as a tool to asses the expansion forces and to avoid deformations.

The efficiency of molar distalization using clear aligners and mini-implants: Two clinical cases.

When using clear aligners, if distalization greater than 3mm is required, there is no real predictable procedure to follow. The aim of this article is to show with two clinical cases the biomechanics of distalizing lower molars with mini-implant anchorage and aligners.

Correction of mandibular deviation and maxillary occlusal canting with mandibular "early" surgery and microscrews: Two case reports.

Facial asymmetry is a common complaint in patients with facial concerns. Some patients have mandibular asymmetries that have light maxillary cant compensation due to a reduced gingival exposure. A common treatment in facial asymmetries is bimaxillary surgery treatment. However, there are no cases of non-severe occlusal plane canting (OPC) with mandibular asymmetry treated with mandibular surgery and miniscrews for the extrusion of the maxillary molars. The aim of this article is to show how to correct mandibular asymmetries combined with OPC by making a single mandibular "early surgery" combined with the extrusion of the maxilla with miniscrews to correct the occlusal plane in order to avoid a Le Fort I surgery. This type of treatment provides lower medical costs, shorter surgeries, and less postoperative discomfort and invasion for patients.

Stability of the anterior arm of three different Hyrax hybrid expanders: an in vitro study.

INTRODUCTION: The force applied to the teeth by fixed orthopaedic expanders has previously been studied, but not the force applied to the orthodontic mini-implant (OMI) used to expand the maxilla with Hyrax hybrid expanders (HHE). OBJECTIVE: The aim of this article was to evaluate the clinical safety of the components (OMI, abutment and double wire arms) of three different force-transmitting systems (FTS) for conducting orthopaedic maxillary expansion: Jeil Medical & Tiger Dental™, Microdent™ and Ortholox™. METHODS: For the realization of this in vitro study of the resistance to mechanical load, three different abutment types (bonded, screwed on, and coupling) and three different OMIs' diameters (Jeil™ 2.5 mm, Microdent™ 1.6 mm and Ortholox™ 2.2 mm) were used. Ten tests for each of these three FTS were carried out in a static lateral load in artificial bone blocks (Sawbones™) by a Galdabini universal testing machine, then comparing its performance. Comparisons of loads, deformations and fractures were carried out by means of radiographs of FTS components in each case. RESULTS: At 1- mm load and within the elastic deformation, FTS values ranged from 67 ± 13 N to 183 ± 48 N. Under great deformations, Jeil & Tiger™ was the one who withstood the greatest loads, with an average 378 ± 22 N; followed by Microdent™, with 201 ± 18 N, and Ortholox™, with 103 ± 10 N. At 3 mm load, the OMIs shaft bends and deforms when the diameter is smaller than 2.5 mm. The abutment fixation is crucial to transmit forces and moments. CONCLUSIONS: The present study shows the importance of a rigid design of the different components of HHEs, and also that HHEs would be suitable for maxillary expansion in adolescents and young adults, since its mean expansion forces exceed 120N. Furthermore, early abutment detachment or smaller mini-implants diameter would only be appropriate for children.

Closing extraction spaces with lingual orthodontics.

There are different ways of closing extraction spaces with lingual orthodontics. One is to use loop mechanics and the other is to use sliding mechanics. This case report describes the treatment of closing spaces using sliding mechanics with and without the use of microscrews. Understanding and applying basic biomechanical principles is necessary for lingual orthodontics and the use of miniscrews. The purpose of this article is to demonstrate the effect of orthodontic miniscrews in controlling anchorage and the basic biomechanical considerations in understanding the influence of the anterior teeth.

Factors associated with mortality in patients with exacerbation of chronic obstructive pulmonary disease hospitalized in General Medicine departments.

We aim to improve knowledge on risk factors that relate to mortality in subjects with exacerbation of chronic obstructive pulmonary disease (COPD) who are hospitalized in General Medicine departments. In a cross-sectional multicenter study, by means of a logistic regression analysis, we assessed the possible association of death during hospitalization with the following groups of variables of participating patients: sociodemographic features, treatment received prior to admission and during hospitalization, COPD-related clinical features recorded prior to admission, comorbidity diagnosed prior to admission, clinical data recorded during hospitalization, laboratory results recorded during hospitalization, and electrocardiographic findings recorded during hospitalization. A total of 398 patients was included; 353 (88.7%) were male, and the median age of the patients was 75 years. Of these patients, 21 (5.3%) died during hospitalization. Only 270 (67.8%) received inhaled ß(2) agonists during hospitalization, while 162 (40.7%) received angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. The median of predicted FEV(1) prior to admission was 42%. A total of 350 patients (87.9%) had been diagnosed with two or more comorbid conditions prior to admission. An association was found between increased risk of death during hospitalization and the previous diagnoses of pneumonia, coronary heart disease, and stroke. In conclusion, comorbidity is an important contributor to mortality among patients hospitalized in General Medicine departments because of COPD exacerbation.

[Factor analysis of health related quality of life in patients admitted to a short stay medical unit]. / Análisis factorial de la calidad de vida relacionada con la salud de pacientes que ingresan en una unidad de corta estancia médica.

BACKGROUND: Disease and hospital admission have a great impact on the quality of life of an individual. AIM: To identify the factors associated with health related quality of life (HRQL) in patients admitted to a Short Stay Medical Unit (SSMU). PATIENTS AND METHODS: Prospective cohort study of 335 patients aged 15 to 99 years (196 males) consecutively admitted to the SSMU. In all we recorded sociodemographic data, number of previous hospital admissions, admission type, main diagnosis, lenght of stay, comorbidities, the Goldberg Depression and Anxiety Scale, the Karnofsky Perfomance Scale, the Barthel Index and quality of life with the EuroQol-5D instrument. After studying the associations between variables, we carried out a factor analysis of those that were significantly related to HRQL. RESULTS: Mean body mass index was 27.7 Kg/m(2) and 83% were emergency admissions. Heart failure, chronic obstructive pulmonary disease exacerbation, acute coronary syndromes and cardiac arrhythmias, constituted 56% of all admissions. HRQL was statistically related to age, gender, educational status, caregiving situation, number of previous admissions, main diagnosis, length of stay, Goldberg scale and Karnofsky, Barthel and Charlson indexes. Factor analysis reduced the original variables to five, which explained 67.8% of the variance, as follows: Factor 1- Karnofsky and Barthel indexes (27.8%); Factor 2- age, educational status, caregiving situation (12.3%); Factor 3- the Goldberg scale (10.4%); Factor 4- admission type (8.8%); Factor 5- main diagnosis (8.4%). CONCLUSIONS: HRQL in patients admitted to Short Stay Medical Unit is partially related to perfomance status, age, social and psychological status, admission type an the main diagnosis.

Análisis factorial de la calidad de vida relacionada con la salud de pacientes que ingresan en una unidad de corta estancia médica / Factor analysis of health related quality of life in patients admitted to a short stay medical unit

Background: Disease and hospital admission have a great impact on the quality of life of an individual: Aim: To identify the factors associated with health related quality of life (HRQL) in patients admitted to a Short Stay Medical Unit (SSMU). Patients and methods: Prospective cohort study of 335 patients aged 15 to 99 years (196 males) consecutively admitted to the SSMU. In all we recorded sociodemographic data, number of previous hospital admissions, admission type, main diagnosis, ¡enght of stay, comorbidities, the Goldberg Depression and Anxiety Scale, the Karnofsky Perfomance Scale, the Barthel Index and quality of life with the EuroQol-5D instrument. After studying the associations between variables, we carried out a factor analysis of those that were significantly related to HRQL. Results: Mean body mass index was 27.7 Kg/m² and 83 percent were emergency admissions. Heart failure, chronic obstructive pulmonary disease exacerbation, acute coronary syndromes and cardiac arrhythmias, constituted 56 percent of all admissions. HRQL was statistically related to age, gender, educational status, caregiving situation, number of previous admissions, main diagnosis, length of stay, Goldberg scale and Karnofsky, Barthel and Charlson indexes. Factor analysis reduced the original variables to five, which explained 67.8 percent of the variance, as follows: Factor 1- Karnofsky and Barthel indexes (27.8 percent); Factor 2- age, educational status, caregiving situation (12.3 percent); Factor 3- the Goldberg scale (10.4 percent); Factor 4- admission type (8.8 percent); Factor 5- main diagnosis (8.4 percent). Conclusions: HRQL in patients admitted to Short Stay Medical Unit is partially related to perfomance status, age, social and psychological status, admission type an the main diagnosis (RevMéd Chile 2009; 137:1163-72).

Peak expiratory flow rate as predictor of inpatient death in patients with chronic obstructive pulmonary disease.

OBJECTIVES: Few studies analyze hospital deaths and related factors in patients with acute exacerbation of chronic obstructive pulmonary disease who require hospitalization. METHODS: A cross-sectional study was done with 284 patients who had been admitted consecutively to the Short Stay Medical Unit at the Juan Canalejo Hospital in A Coruña. RESULTS: Eleven patients (3.9%) died. The independent variables for predicting death were the peak expiratory flow (OR, 0.96; 95% CI, 0.94 to 0.98), long-term oxygen therapy (OR, 12.46; 95% CI, 2.1 to 72.4), and body mass index (OR, 0.73; 95% CI, 0.59 to 0.90). A peak expiratory flow < 150 L/min showed the best specificity and positive predictive value with maximum sensitivity for predicting death. The results of the arterial blood gasses and the functional tests did not predict hospital death. CONCLUSIONS: Peak expiratory flow was the most important predictive value for determining the risk of death in patients who required hospitalization for acute exacerbation of chronic obstructive pulmonary disease. Additional studies are required to validate these findings.

Acute renal infarction as a cause of low-back pain.

Detection of acute renal infarction is often delayed or missed because of both the rarity of the disease and its nonspecific clinical presentation. Abrupt onset of low-back pain in a patient at high risk for a thromboembolic event may be the first indication of renal infarction. We report a case of acute renal infarction and review its diagnosis and management.