Total knee and hip arthroplasty in a patient with dwarfism: a report of a patient with a spondylo-epiphyseal dysplasia

In patients with spondylo-epiphyseal dysplasia, coxa vara and genu valgum deformities cause malalignment, which lead to early degenerative changes in hip and knee. It is mandatory to give them a functional replacement for their deformed, painful knees and hips to lead a normal life. We report a patient with inherited dwarfism on whom a replacement of knee and hip was performed.     

Physical properties of root cementum: Part 3. Hardness and elastic modulus after application of light and heavy forces.

BACKGROUND: The aims of this investigation were to evaluate the hardness and elastic modulus of untreated human premolar cementum and to investigate the changes after application of light and heavy orthodontic forces. METHODS: Thirty-six maxillary and mandibular first premolars were collected from 16 prospective orthodontic patients. The patients were assigned to 1 of 2 groups. Group I (light force) consisted of 8 subjects (4 male, 4 female, mean age 14.8 years) who had 25 g of buccally directed orthodontic force applied to the first premolars on 1 side. Group II (heavy force) consisted of 9 subjects (7 male, 2 female, mean age 13.8 years) who had 225 g of buccally directed orthodontic force applied to first premolars on 1 side. Contralateral premolars served as the control in both groups. The force was applied for 4 weeks; then each first premolar was extracted and stored in deionized water. Physical properties were tested on unprepared cementum on buccal and lingual surfaces at the cervical, middle, and apical thirds with an ultra-micro-indentation system. RESULTS: Mean (+/- standard deviation) hardness of the untreated cementum at the cervical, middle, and apical thirds, respectively, was 0.25 +/- 0.09 GPa, 0.24 +/- 0.07 GPa, and 0.18 +/- 0.06 GPa on the buccal surface and 0.24 +/- 0.08 GPa, 0.24 +/- 0.06 GPa, and 0.21 +/- 0.06 GPa on the lingual surface. Mean elastic modulus at the cervical, middle, and apical thirds, respectively, was 4.4 +/- 2.4 GPa, 3.4 +/- 2.0 GPa, and 2.4 +/- 1.8GPa on the buccal surface and 3.8 +/- 2.1 GPa, 3.2 +/- 1.4 GPa, and 2.4 +/- 1.5 GPa on the lingual surface. CONCLUSIONS: The mean hardness and elastic modulus of untreated human premolar cementum gradually decreased from cervical to apical regions of the buccal and lingual surfaces. A similar decrease was observed in the experimental teeth of light-force and heavy-force groups. There were no statistically significant differences between the control and experimental teeth; this is probably due to large intraindividual variation.     

The effects of samarium-cobalt magnets and pulsed electromagnetic fields on tooth movement

The purpose of this study was to determine whether the application of either samarium cobalt magnets or pulsed electromagnetic fields could increase the rate and amount of orthodontic tooth movement observed in guinea pigs. In addition, the objective was to evaluate the effect of a magnetic field on bony physiology and metabolism and to monitor for possible systemic side effects. Fifteen grams of laterally directed orthodontic force were applied to move the maxillary central incisors of a sample of 18 young male Hartley guinea pigs divided into three groups: group 1, an orthodontic coil spring was used to move the incisors; group 2, a pair of samarium-cobalt magnets provided the tooth moving force; and group 3, a coil spring was used in combination with a pulsed electromagnetic field. The results showed that both the static magnetic field produced by the samarium-cobalt magnets and the pulsed electromagnetic field used in combination with the coil spring were successful in increasing the rate of tooth movement over that produced by the coil springs alone. The mechanism producing this effect appears to have involved a reduction in the “lag” phase often seen in orthodontic tooth movement. Both magnetically stimulated groups also showed increases in both the organization and amount of new bone deposited in the area of tension between the orthodontically moved maxillary incisors. (AM J ORTHOD DENTOFAC ORTHOP 1995;107:578-88.)     

The adaptive remodeling of condylar cartilage---a transition from chondrogenesis to osteogenesis

Mandibular condylar cartilage is categorized as articular cartilage but markedly distinguishes itself in many biological aspects, such as its embryonic origin, ontogenetic development, post-natal growth mode, and histological structures. The most marked uniqueness of condylar cartilage lies in its capability of adaptive remodeling in response to external stimuli during or after natural growth. The adaptation of condylar cartilage to mandibular forward positioning constitutes the fundamental rationale for orthodontic functional therapy, which partially contributes to the correction of jaw discrepancies by achieving mandibular growth modification. The adaptive remodeling of condylar cartilage proceeds with the biomolecular pathway initiating from chondrogenesis and finalizing with osteogenesis. During condylar adaptation, chondrogenesis is activated when the external stimuli, e.g., condylar repositioning, generate the differentiation of mesenchymal cells in the articular layer of cartilage into chondrocytes, which proliferate and then progressively mature into hypertrophic cells. The expression of regulatory growth factors, which govern and control phenotypic conversions of chondrocytes during chondrogenesis, increases during adaptive remodeling to enhance the transition from chondrogenesis into osteogenesis, a process in which hypertrophic chondrocytes and matrices degrade and are replaced by bone. The transition is also sustained by increased neovascularization, which brings in osteoblasts that finally result in new bone formation beneath the degraded cartilage.     

Evaluation of XP-endo Shaper,Reciproc Blue,and ProTaper Universal NiTi Systems on Dentinal Microcrack Formation Using Micro–Computed Tomography

Introduction

The purpose of the present study was to evaluate the frequency of dentinal microcracks observed after root canal preparation with XP-endo Shaper (XP), Reciproc Blue (RB), and ProTaper Universal (PTU) instruments using micro-computed tomographic (μCT) analysis.

Third Generation Ventricular Assist Device: Mid‐Term Outcomes of the HeartWare HVAD in Pediatric Patients

The HeartWare HVAD is a small, third generation continuous flow pump that is intracorporeally placed for support of a failing ventricle in adult patients. This device is small in size when compared to other left ventricular assist devices and can therefore be used in smaller sized pediatric patients. We present our initial experience using the HVAD as a bridge to heart transplantation in the pediatric population. We performed a retrospective, single center, nonrandomized review of 17 pediatric patients who underwent HVAD implantation between June 2013 and March 2016. The primary endpoints evaluated in this study were overall survival to heart transplantation, ongoing device support, or death. In this patient cohort, nine (53%) of 17 patients were male. The median age of the patients was 13.4 ± 3.8 (range 5–17) years. The median body surface area was 1.4 ± 0.4(0.7–2) m². Etiologies of heart failure requiring HVAD support were dilated cardiomyopathy (n = 8), myocarditis (n = 5) and noncompaction cardiomyopathy (n = 4). The overall mean length of HVAD support was 254 ± 298 (range 2–804) days. A successful outcome (bridge to transplant and ongoing mechanical support) was achieved in 13 patients (76.5%). Of the 13 patients, nine (69.2%) were bridged to heart transplantation and four continue to receive support (30.7%) and are eligible for transplantation. Post‐transplant survival has been 100%, with a mean follow‐up of 296 ± 264.5 (range 18–785) days. The most common complication was pump thrombosis (23.5%) in follow‐up. Four patients (23.5%) experienced no complications. The HVAD continuous flow ventricular assist device can be safely used to bridge pediatric patients to cardiac transplantation. Favorable outcomes of this device are comparable to the adult population. This analysis demonstrated safe and effective implantation of the HVAD System in a child with a BSA of 0.7 m².