The use of the Greulich-Pyle method in a longitudinal growth study

The Greulich-Pyle method of assessing skeletal maturity is essentially suited to cross-sectional analyses, though it may be used retrospectively in longitudinal studies, through the technique of regression analysis. When applied to the serial records of 120 Philadelphia children, considerable variability in maturation rate may be observed. This variability is both within and between-individuals. While most seems to be random, there is the strong suggestion that individuals who are, during infancy and early childhood, slow maturers, speed up to greater-than-average rates during middle childhood and adolescence; the opposite may be inferred in those who are initially rapid maturers. Though these findings were consistent in the Philadelphia sample, they may be artifacts of the Greulich-Pyle standards.     

Cephalometric study of facial growth in children after combined pushback and pharyngeal flap operations.

Linear and angular cephalometric measurements of children who had had combined palatal pushbacks and superiorly-based pharyngeal flaps do not show later growth retardation of the face. There was an inherent tendency for children with overt clefts of the secondary palate, classic submucous clefts, or occult submucous clefts to demonstrate pre-operatively a narrow SNA and SNB--but the difference between these angles (ANB) was normal.     

A comparative study of facial growth in Homo and Macaca

Sections were prepared throughout all areas of the various facial bones in young, growing Rhesus monkeys. The detailed distribution of resorptive and depository surfaces and the distribution of endosteal and periosteal bone tissue types were determined. From this information, the sequence of remodeling changes associated with the growth of the facial skeleton was then interpreted. This study is a sequal to previous reports in which growth and remodeling processes in the human face were described using similar procedures. In the present report, growth changes in the monkey and human facial skeleton are compared and contrasted. The general plan of facial growth is similar in both species, but major differences exist in the area of the muzzle. The maxillary arch in the monkey is entirely depository in nature, and it grows in a forward and downward direction as the maxillary tuberosity simultaneously grows backward. In the human, the forward part of the maxillary arch is resorptive in character. This contrasting growth factor results in a downward but not forward movement of this area. The result is decreased prognathism. Other differences in growth pattern exist in the forehead, malar, chin, and orbit. The developmental and phylogenetic basis for the upright human face is discussed and evaluated.     

A study of facial growth in the sooty mangabey Cercocebus atys

This study examines the pattern of facial bone growth remodelling in the sooty mangabey (Cercocebus atys) by scanning electron microscopy (SEM) of high-accuracy replicas. The efficacy of the technique is appraised by SEM interpretations of facial remodelling in the crab-eating macaque (Macaca fascicularis) and correlative histological examination. The results indicate that the distribution of depository and resorptive areas in Cercocebus closely parallels that which has been observed in Macaca. It is suggested that the different adult facial morphologies in the sooty mangabey and crab-eating macaque are the result of changes in the rates of remodelling events that may be coupled with different patterns of sutural growth (which could not be studied by SEM).     

Modeling capsule tissue growth around disk-shaped implants: a numerical and in vivo study

We propose a new mathematical model that describes the growth of fibrous tissue around rigid, disk-shaped implants. A solution methodology based on an efficient regularized iterative method is presented to calibrate the model from some measurements of the capsule tissue concentration. Numerical results obtained with synthetic data are presented to demonstrate the ability of the proposed solution methodology to determine the model parameters corresponding to a given implant. In addition, numerical results obtained with experimental data are presented to illustrate the validity of the proposed model.     

Methods to quantify soft-tissue based facial growth and treatment outcomes in children: a systematic review

Context

Technological advancements have led craniofacial researchers and clinicians into the era of three-dimensional digital imaging for quantitative evaluation of craniofacial growth and treatment outcomes.

Objective

To give an overview of soft-tissue based methods for quantitative longitudinal assessment of facial dimensions in children until six years of age and to assess the reliability of these methods in studies with good methodological quality.

Data Source

PubMed, EMBASE, Cochrane Library, Web of Science, Scopus and CINAHL were searched. A hand search was performed to check for additional relevant studies.

Study Selection

Primary publications on facial growth and treatment outcomes in children younger than six years of age were included.

Data Extraction

Independent data extraction by two observers. A quality assessment instrument was used to determine the methodological quality. Methods, used in studies with good methodological quality, were assessed for reliability expressed as the magnitude of the measurement error and the correlation coefficient between repeated measurements.

Results

In total, 47 studies were included describing 4 methods: 2D x-ray cephalometry; 2D photography; anthropometry; 3D imaging techniques (surface laser scanning, stereophotogrammetry and cone beam computed tomography). In general the measurement error was below 1 mm and 1° and correlation coefficients range from 0.65 to 1.0.

Conclusion

Various methods have shown to be reliable. However, at present stereophotogrammetry seems to be the best 3D method for quantitative longitudinal assessment of facial dimensions in children until six years of age due to its millisecond fast image capture, archival capabilities, high resolution and no exposure to ionizing radiation.     

Fungal growth inside saline-filled implants and the role of injection ports in fungal translocation: in vitro study

Infection is a serious complication of breast augmentation and tissue expansion with inflatable devices. Several reports have shown that fungi may be able to survive, colonize, and even cause infection in saline-filled devices. The mechanism of how they penetrate, spread, and colonize inside the inflatable implants is not exactly understood. The authors assessed both the expander membrane and the port in terms of leakage and penetration of Candida albicans and Aspergillus niger in an in vitro model. Thirty saline-filled expanders connected to the injection port were placed in sterile containers filled with tryptic soy broth culture medium to simulate the clinical situation in phases I and II. Intact and multipunctured ports were used in the first and second phases of the study, respectively. Either the container or the implant was inoculated with one of these fungi, and six implants in containers without fungal inoculation served as controls. As a third phase, intraluminal survival of fungi was investigated in saline-filled containers (n = 12) in 21 days. The silicone membrane, with its intact connecting tube and port, was impermeable to these fungi, whereas both fungi were able to diffuse inside-out or outside-in through the punctured ports. C. albicans did not survive beyond 18 days in saline, whereas A. niger continued to multiply at day 21. Chemical analyses of the implant fluids revealed that the contents of the culture medium diffused into the implants in phases I and II. The data show that an intact silicone membrane is impermeable to fungi, and punctured ports allow translocation of fungi into the implants. Fungi can grow and reproduce in a saline-only environment, and their survival periods differ among the species. Furthermore, their survival may be enhanced by the influx of substances through the implant shell.     

The effect of unilateral partial facial paralysis on nasofrontal sutural growth: an experimental study in the rabbit.

In a previous study in the rabbit, it was demonstrated that paralysis of the midfacial musculature results in decreased anteroposterior growth of the snout. At the end of growth, these animals showed macroscopically striking similarities to animals with unilateral fusion of the nasofrontal suture. In this study, whether nasofrontal sutural growth is unilaterally restricted in animals with unilateral partial facial paralysis was investigated. A left-sided partial facial paralysis was induced in sixteen 12-day-old New Zealand White rabbits. At the ages of 5, 9, 12, and 17 weeks, four animals were randomly assigned to be killed for analysis of nasofrontal sutural growth. In each animal, the left experimental side was compared with the right control side. By means of histomorphometric measurements, it was shown that diminished sutural growth activity was present on the left paralyzed side in periods of rapid growth. On the other hand, no significant alterations in sutural width were found. These findings seem to explain some of the macroscopic growth alterations (i.e., diminished anterior maxillary length) observed in rabbits with unilateral partial facial paralysis.     

The use of Gore-Tex implants in aesthetic surgery of the face.

Deep wrinkles and folds usually are not completely or permanently corrected with face lifting, fat or collagen injections, chemical peels, and other known procedures. It is suggested that a permanent implant, well tolerated by human tissues, could be helpful as an isolated or associated procedure. An expanded synthetic polymer known as Gore-Tex expanded polytetrafluoroethylene soft-tissue patch is available and is easy to use to approximate and correct defects; it also can be used as a filling material or to replace other kinds of prostheses to get better projection of frontal, orbital, malar, and chin areas. I have used this material in my clinic for 5 years. Indications and results of the first cosmetic cases are reported herein.     

Assessment of the genetic risks of a metallic alloy used in medical implants

The use of artificial implants provides a palliative or permanent solution for individuals who have lost some bodily function through disease, an accident or natural wear. This functional loss can be compensated for by the use of medical devices produced from special biomaterials. Titanium alloy (Ti-6Al-4V) is a well-established primary metallic biomaterial for orthopedic implants, but the toxicity of the chemical components of this alloy has become an issue of concern. In this work, we used the MTT assay and micronucleus assay to examine the cytotoxicity and genotoxicity, respectively, of an extract obtained from this alloy. The MTT assay indicated that the mitochondrial activity and cell viability of CHO-K1 cells were unaffected by exposure to the extract. However, the micronucleus assay revealed DNA damage and an increase in micronucleus frequency at all of the concentrations tested. These results show that ions released from Ti-6Al-4V alloy can cause DNA and nuclear damage and reinforce the importance of assessing the safety of metallic medical devices constructed from biomaterials.