Lymphatic circulation in astronauts: basic knowledge, challenges and perspectives

Space missions expose the astronauts' bodies to various stressors, including microgravity. While numerous studies have investigated the effects of this stressor, research on its impact on the lymphatic system remains confidential. This review highlights the importance of scientific research into the human lymphatic system exposed to long-duration space missions. The safety of astronauts is a major issue. Chronic slowing of lymphatic drainage disrupts the balance of fluid and macromolecule exchange within poorly drained anatomical areas. Their extracellular matrix gradually becomes the site of dispersed deposits of degraded proteins and increased local water content. The interaction between these two phenomena leads to mutual amplification, resulting in a slow, gradual increase in pressure within the impacted tissue, which undergoes an expansion known as edema. The speed at which these pathophysiological processes take hold includes the extent of the lymphatic insufficiency and any compensatory measures that may or may not be put in place. Lymphatics are present everywhere in the body where tissues receive blood. Organs such as the brain, heart, and intestines, among others, as well as local immune function, can be damaged over time when their lymphatic system becomes chronically insufficient. The human clinical experience of lymphatic insufficiency tells us that the onset of edema takes time and is an insidious but inevitable phenomenon if adequate compensation does not occur. The time required for the pathophysiological consequences of lymphatic insufficiency to become established does not coincide with the time allocated to bed rest experiments or current space missions. With the prospect of longer space missions, lymphatic insufficiency linked to microgravity could unexpectedly become a major obstacle to human life in space.

SALIVA-based diagnostic approach for diabetes mellitus: a step towards non-invasive detection - a scoping review

OBJECTIVE

Diabetes mellitus (DM) is a chronic autoimmune disease whose main feature is chronic hyperglycemia. The causes of DM are impaired insulin secretion, impaired insulin action, or both. Saliva is a biofluid that can be considered as a "mirror" reflecting our body's health status; with the rapid advancement in salivaomics, saliva, being a non-invasive and safe source, could be a substitute for blood in the diagnosis and prognosis of diseases. As there are no precise guidelines about the salivary biomarkers correlated with the diagnosis of diabetes, a review was conducted to verify whether saliva analysis can be feasible and which biomarkers are more reliable, for the diagnosis of this disease.

MATERIALS AND METHODS

A literature search was performed through PubMed, Medline, Scopus, Web of Science, LILACS, Open Grey, and Cochrane Library databases. The "PRISMA" guidelines were used for the following review, and thirty-three studies were analyzed.

RESULTS

Almost all salivary glucose studies suggest that the estimation of this biomarker can be used as a potential indicator. Furthermore, studies that considered other biomarkers such as 1,5-anhydroglucitol, alpha-amylase, N-acetyl-β-D-hexosaminidase, asprosin, resistin, and fructosamine reported that these biomarkers resulted to be potentially useful for diabetes screening and diagnosis, with the exception of the cystatin SA.

CONCLUSIONS

In conclusion, several salivary biomarkers could be useful for monitoring DM, but it would be necessary to further expand the research and define precise values for each marker in order to predict with reasonable confidence if an individual is healthy or suffering from diabetes. Finally, standardized saliva collection and processing techniques are key to minimizing interindividual variability in saliva composition.

The potential preventive role of a dietary supplement containing hydroxytyrosol in COVID-19: a multi-center study

OBJECTIVE

COVID-19 is a disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which emerged as a global pandemic in 2019. Its main symptoms include fever, cough, fatigue, and, in severe cases, pneumonia, acute respiratory distress syndrome, and organ failure, which can be life-threatening. Various therapies have been proposed for treating COVID-19, among which antiviral drugs and monoclonal antibodies, but natural molecules have gained attention for their potential antiviral properties against various viral infections, including COVID-19. The use of hydroxytyrosol (HT), a polyphenol from the olive tree possessing antioxidant, anti-inflammatory, and anti-viral properties, has been proposed to reduce COVID-19 infection.

SUBJECTS AND METHODS

A total of 443 subjects were recruited from four centers, located in Albania, Germany, and Italy (Milan and Trento provinces). The participants were randomly assigned to receive either the dietary supplement containing HT or a placebo for a duration of one month.

RESULTS

Analysis of the study data revealed that, among the subjects who tested positive for COVID-19 during the study, 36% belonged to the group that received the dietary supplement containing HT, while 64% belonged to the placebo group. The difference was statistically significant. These findings suggest that the use of a dietary supplement containing HT may have a possible preventive effect against COVID-19 infection.

CONCLUSIONS

The study's results indicate that the dietary supplement containing HT shows promise as a possible preventive measure against COVID-19 infection. Large-scale, randomized clinical trials and animal studies could be useful to provide more definitive conclusions on HT's possible potential preventive effects against COVID-19, which could potentially supplement existing therapies and contribute to fighting COVID-19 infection.

Salivary proteomic profile of young healthy subjects

Background: The incidence of noncommunicable diseases (NCDs) has been rapidly ramped up worldwide. Hence, there is an urgent need to non-invasively detect NCDs possibly by exploiting saliva as a 'liquid biopsy' to identify biomarkers of the health status. Since, the absence of standardized procedures of collection/analysis and the lack of normal ranges makes the use of saliva still tricky, our purpose was to outline a salivary proteomic profile which features healthy individuals. Methods: We collected saliva samples from 19 young blood donors as reference population and the proteomic profile was investigated through mass-spectrometry. Results: We identified 1,004 proteins of whose 243 proteins were shared by all subjects. By applying a data clustering approach, we found a set of six most representative proteins across all subjects including Coronin-1A, F-actin-capping protein subunit alpha, Immunoglobulin J chain, Prosaposin, 78 kDa glucose-regulated protein and Heat shock 70 kDa protein 1A and 1B. Conclusion: All of these proteins are involved in immune system activation, cellular stress responses, proliferation, and invasion thus suggesting their use as biomarkers in patients with NCDs.

The Role of Olive Tree Polyphenols in the Prevention of COVID-19: A Scoping Review, part 1

Abstract

The global COVID-19 outbreak, started in December 2019, resulted in severe financial losses and extraordinary health crises. Finding a potent and secure medication candidate to treat SARS-CoV-2 infection and its symptoms is still an urgent global need. After reviewing previous studies, olive leaves, being rich in polyphenolic compounds (a large class of bioactive substances naturally found in plants), were proposed as a viable co-therapy supplement to treat and improve clinical symptoms in COVID-19 patients. It has long been known that olive tree polyphenols-such as oleuropein, hydroxytyrosol, verbascoside, as well as triterpenoids like maslinic, ursolic, and oleanolic acids-have anti-inflammatory and multitarget antiviral effects on several virus families, and they could be one of the reasons of the beneficial effects of the Mediterranean diet against COVID-19. Thus, olive tree poly-phenols were tested in silico and in vitro for preventing SARS-CoV-2 infection, claiming that they have beneficial effects. Nevertheless, there is still a small number of research studies on this topic. The aim of this scoping review is to provide more information and offer an opinion on the feasibility of using olive tree polyphenols as a springboard for the creation of innovative natural remedies against this viral illness, ultimately planning future relevant studies.

Bioetics Issues of Artificial Placenta and Artificial Womb Technology

Abstract

The worldwide infertility crisis and the increase in mortality and morbidity among infants, due to preterm births and associated complications, have stimulated research into artificial placenta (AP) and artificial womb (AW) technology as novel solutions. These technologies mimic the natural environment provided in the mother's womb, using chambers that ensure the supply of nutrients to the fetus and disposal of waste substances through an appropriate mechanism. This review aims to highlight the background of AP and AW technologies, revisit their historical development and proposed applications, and discuss challenges and bioethical and moral issues. Further research is required to investigate any negative effects of these new technologies, and ethical concerns pertaining to the structure and operation of this newly developed technology must be addressed and resolved prior to its introduction to the public sphere.

The Role of Olive Tree Polyphenols In The Prevention of COVID-19: A Scoping Review Part 2

Abstract

The recent COVID-19 pandemic caused by SARS-CoV-2 affected hundreds of millions of people and caused millions of deaths. There are few effective medications against SARS-CoV-2, and several studies attempted to make drugs based on natural components, such as olive leaves. Olive leaves are rich in polyphenolic compounds, which were proposed as a viable co-therapy supplement to treat and improve clinical symptoms in COVID-19 patients. Polyphenols have renown anti-inflammatory and multitarget antiviral effects on several virus families, which could be among the reasons of the beneficial effects of the Mediterranean diet against COVID-19. This scoping review is focused on the effect of olive tree polyphenols as a natural remedy to inhibit SARS-CoV-2, mainly discussing their influence on the process of viral entry into host cells by endocytosis.

Human Cloning: Biology, Ethics, and Social Implications

Abstract

This scholarly article delves into the multifaceted domains of human cloning, encompassing its biological underpinnings, ethical dimensions, and broader societal implications. The exposition commences with a succinct historical and contextual overview of human cloning, segueing into an in-depth exploration of its biological intri-cacies. Central to this biological scrutiny is a comprehensive analysis of somatic cell nuclear transfer (SCNT) and its assorted iterations. The accomplishments and discoveries in cloning technology, such as successful animal cloning operations and advances in the efficiency and viability of cloned embryos, are reviewed. Future improvements, such as reprogramming procedures and gene editing technology, are also discussed. The discourse extends to ethical quandaries intrinsic to human cloning, entailing an extensive contemplation of values such as human dignity, autonomy, and safety. Furthermore, the ramifications of human cloning on a societal plane are subjected to scrutiny, with a dedicated emphasis on ramifications encompassing personal identity, kinship connections, and the fundamental notion of maternity. Culminating the analysis is a reiteration of the imperative to develop and govern human cloning technology judiciously and conscientiously. Finally, it discusses several ethical and practical issues, such as safety concerns, the possibility of exploitation, and the erosion of human dignity, and emphasizes the significance of carefully considering these issues.

In Memory of Professor Derek Pheby

Abstract

Professor Derek Pheby's passing in November 2022 marked a profound loss for the scientific community. Professor Derek Pheby, a stalwart figure in the fields of autoimmune diseases and bioethics, was known for his dedication to scientific research and patients' support, particularly for those affected by paraneoplastic autoimmune syndromes. Professor Pheby made significant contributions to research, especially about Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). His leadership of the ME Biobank and scientific coordination of EUROMENE demonstrated his commitment to pushing boundaries and fostering international collaborations. Professor Pheby's scientific work addressed various aspects of ME/CFS, from physician education to patient needs, the development of a post-mortem tissue bank, and effective treatments. Beyond his medical career, Professor Pheby was a crucial member of the Independent Ethics Committee of MAGI, he was a poet, humanitarian, and advocate for child protection. His generosity and boundless spirit left an enduring legacy, fostering innovative research in the pursuit of combating autoimmune diseases.

What is the use of nutraceuticals in dentistry? A scoping review

OBJECTIVE

Recently, nutraceuticals have been widely explored in many medical fields and their use is also increasing in oral and dental problems. Since the nutraceutical evidence landscape in the literature has not been fully elucidated yet, this review aims to examine the effects of commercially available nutraceuticals and their potential evidence and applications in dentistry.

MATERIALS AND METHODS

A scoping review was conducted following the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR)" checklist. The electronic search was performed using PubMed/MEDLINE, EMBASE, the Cochrane Library, and Web of Science on March 2022. The inclusion criteria include humans, clinical trials, randomized controlled trials (RCT), reviews, and systematic reviews published over the last ten years.

RESULTS

18 studies met the eligibility criteria. There were 2 RCTs, 11 systematic reviews, and four narrative reviews. In most studies, the clinical indications were oral leucoplakia, periodontitis, osseointegration of implants, oral mucositis, oral clefts, and oral health. Probiotics, prebiotics, polyunsaturated fatty acids, and vitamins A, B, C, D, and E were the most common nutraceuticals used in dentistry.

CONCLUSIONS

Nutraceuticals are foods that, according to the literature, may be useful for preventing and treating dental diseases.

3D Computed Tomography vs. 2D radiography: comparison of 3D direct anthropometry with 2D norm calculations and analysis of differences in soft tissue measurements

OBJECTIVE

The aim of this study was twofold: (1) to compare soft tissue measurements of the same distances obtained from 3D computed tomography reconstructions with 2D cephalometric radiograms, (2) to compare data from 3D measurements from direct anthropometry and 2D "norms" for the facial measurements.

PATIENTS AND METHODS

A total of 40 Caucasian patients that had their CBCT scans for various dental and dentoskeletal reasons were enrolled in this study. All the patients had large field of view (from the forehead to the chin). The data were stored in DICOM format and imported into a software for 3D reconstructions. After 3D facial soft tissue model generation, the distances between 18 soft tissue points were measured. The 3D soft tissue analysis was performed, and the facial indices were calculated. The mean 3D values were compared with 2D measurements performed on lateral cephalograms and Arnett's and Farkas' norms. The measurements were statistically compared using Student's t-test.

RESULTS

Assessments from 2D and 3D measurements showed no statistical difference except for the distance Pogonion (for both male and female) and Labial superius prominence (females) to the True Vertical Line in 2D /Plane in case of 3D measurements. There was a significant difference between all 3D measurements and Arnett's and anthropometric Farkas' "norms". The mean difference between Farkas' "norms" and 3D measurements was within 3 mm for 70% of measurements.

CONCLUSIONS

According to the results, 3D soft tissue analysis allows for complete diagnostic determination. The 3D "norms" are to be verified on a greater sample.

In vitro and clinical studies on the efficacy of α-cyclodextrin and hydroxytyrosol against SARS-CoV-2 infection

OBJECTIVE

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new coronavirus responsible for the current pandemic of coronavirus disease 2019 (COVID-19). This virus attacks cells of the airway epithelium by binding transmembrane angiotensin-converting enzyme 2 (ACE2). Hydroxytyrosol has anti-viral properties. Alpha-cyclodextrin can deplete sphingolipids and phospholipids from cell membranes. The aim of the present experimental study was to evaluate the efficacy of α-cyclodextrin and hydroxytyrosol in improving defenses against SARS-CoV-2 infection in in vitro cell models and humans.

PATIENTS AND METHODS

For in vitro experiments on Vero E6 cells, RNA for RT-qPCR analysis was extracted from Caco2 and human fibroblast cell lines. For study in humans, the treatment group consisted of 149 healthy volunteers in Northern Cyprus, considered at higher risk of SARS-CoV-2 infection than the general population. The volunteers used nasal spray containing α-cyclodextrin and hydroxytyrosol for 4 weeks. The control group consisted of 76 healthy volunteers who did not use the spray.

RESULTS

RT-qPCR experiments on targeted genes involved in endocytosis showed a reduction in gene expression, whereas cytotoxicity and cytoprotective tests showed that the compounds exerted a protective effect against SARS-CoV-2 infection at non-cytotoxic concentrations. None of the volunteers became positive to SARS-CoV-2 RT-qPCR assay during the 30 days of treatment.

CONCLUSIONS

Treatment with α-cyclodextrin and hydroxytyrosol nasal spray improved defenses against SARS-CoV-2 infection and reduced synthesis of viral particles.

Scoping review on the role and interactions of hydroxytyrosol and alpha-cyclodextrin in lipid-raft-mediated endocytosis of SARS-CoV-2 and bioinformatic molecular docking studies

OBJECTIVE

The aim of the study was to show the effect that two naturally occurring compounds, a cyclodextrin and hydroxytyrosol, can have on the entry of SARS-CoV-2 into human cells.

MATERIALS AND METHODS

The PubMed database was searched to retrieve studies published from 2000 to 2020, satisfying the inclusion criteria. The search keywords were: SARS-CoV, SARS-CoV-2, coronavirus, lipid raft, endocytosis, hydroxytyrosol, cyclodextrin. Modeling of alpha-cyclodextrin and hydroxytyrosol were done using UCSF Chimera 1.14.

RESULTS

The search results indicated that cyclodextrins can reduce the efficiency of viral endocytosis and that hydroxytyrosol has antiviral properties. Bioinformatic docking studies showed that alpha-cyclodextrin and hydroxytyrosol, alone or in combination, interact with the viral spike protein and its host cell receptor ACE2, thereby potentially influencing the endocytosis process.

CONCLUSIONS

Hydroxytyrosol and alpha-cyclodextrin can be useful against the spread of SARS-CoV-2.

Effects of aging and cyclosporin a on collagen turnover in human gingiva

Background:

We aimed at characterizing the aging gingiva analyzing: i) collagen content and turnover in human gingival tissues and fibroblasts obtained from healthy young and aging subjects. ii) the effect of cyclosporin A administration in human cultured gingival fibroblasts obtained from aging compared to young subjects.

Methods:

Morphological analysis was performed on haematoxylin-eosin and Sirius red stained paraffin-embedded gingival biopsies from young and aging healthy subjects. The expression of the main genes and proteins involved in collagen turnover were determined by real time PCR, dot blot and SDS-zymography on cultured young and aging gingival fibroblasts, and after cyclosporin A administration.

Results:

Our results suggest that in healthy aged people, gingival connective tissue is characterized by a similar collagen content and turnover. Collagen turnover pathways are similarly affected by cyclosporin A treatment in young and aging gingival fibroblasts.

Conclusions:

Cyclosporin A administration affects gingival collagen turnover pathways in young and aging fibroblasts at the same extent, suggesting that during aging cyclosporin A administration is not related to relevant collagen turnover modifications.

Electromyographic standardized indices in healthy Brazilian young adults and data reproducibility

The determination of normal parameters is an important procedure in the evaluation of the stomatognathic system. We used the surface electromyography standardization protocol described by Ferrario et al. (J Oral Rehabil. 2000;27:33-40, 2006;33:341) to determine reference values of the electromyographic standardized indices for the assessment of muscular symmetry (left and right side, percentage overlapping coefficient, POC), potential lateral displacing components (unbalanced contractile activities of contralateral masseter and temporalis muscles, TC), relative activity (most prevalent pair of masticatory muscles, ATTIV) and total activity (integrated areas of the electromyographic potentials over time, IMPACT) in healthy Brazilian young adults, and the relevant data reproducibility. Electromyography of the right and left masseter and temporalis muscles was performed during maximum teeth clenching in 20 healthy subjects (10 women and 10 men, mean age 23 years, s.d. 3), free from periodontal problems, temporomandibular disorders, oro-facial myofunctional disorder, and with full permanent dentition (28 teeth at least). Data reproducibility was computed for 75% of the sample. The values obtained were POC Temporal (88.11 +/- 1.45%), POC masseter (87.11 +/- 1.60%), TC (8.79 +/- 1.20%), ATTIV (-0.33 +/- 9.65%) and IMPACT (110.40 +/- 23.69 microV/microV.s %). There were no statistical differences between test and retest values (P > 0.05). The Technical Errors of Measurement (TEM) for 50% of subjects assessed during the same session were 1.5, 1.39, 1.06, 3.83 and 10.04. For 25% of the subjects assessed after a 6-month interval, the TEM were 0.80, 1.03, 0.73, 12.70 and 19.10. For all indices, there was good reproducibility. These electromyographic indices could be used in the assessment of patients with stomatognathic dysfunction.

The influence of occlusion on jaw and neck muscle activity: a surface EMG study in healthy young adults

The electromyographic (EMG) characteristics of masseter, temporalis and sternocleidomastoid (SCM) muscles during maximum voluntary teeth clench were assessed in 27 male and 35 female healthy young adults. Subjects were divided into two groups: (i) 'complete' Angle Class I (bilateral, symmetric canine and molar Class I relationships), and (ii) 'partial' Angle Class I (one to three canine/molar Class I relationships, the remaining relationships were Class II or Class III). On average, standardized muscular symmetry ranged 80.7-87.9%. During maximum voluntary teeth clench, average co-contraction of SCM muscle was 13.7-23.5% of its maximum contraction. On average, all torque coefficients (potential lateral displacing component) were >90%, while all antero-posterior coefficients (relative activities of masseter and temporalis muscles) were >85%. The average integrated areas of the masseter and temporalis EMG potentials over time ranged 87.4-106.8 muV/muV s%. Standardized contractile muscular activities did not differ between 'complete' and 'partial' Angle Class I, and between sexes (two-way analysis of variance). A trend toward a larger intragroup variability in EMG indices was observed in the subjects with 'partial' Angle Class I than in those with 'complete' Angle Class I (significant difference for the temporalis muscle symmetry, P = 0.013, analysis of variance). In conclusion, the presence of a complete or partial Angle occlusal Class I did not seem to influence the standardized contractile activities of masseter, temporalis and SCM muscles during a maximum voluntary clench. Subjects with a 'complete' Angle Class I were somewhat a more homogenous group than subjects with 'partial' Angle Class I.

Morphometry of the ear in Down's syndrome subjects

The three-dimensional coordinates of 13 soft-tissue landmarks on the ears were obtained by a computerized digitizer in 28 subjects with Down's syndrome aged 12-45 years, and in 449 sex, age and ethnic group matched controls. From the landmarks, left and right linear distances (ear width and length), ratios (ear width-to-ear length), areas (ear area), angles (angle of the auricle versus the facial midplane) and the three-dimensional symmetry index were calculated. For both males and females, all linear dimensions and areas were significantly (Analysis of Variance, P < 0.001) larger in the reference subjects than in the subjects with Down's syndrome. All values significantly increased as a function of age (P < 0.05); the increment was larger in the reference subjects than in the subjects with Down's syndrome. On both sides of the face, the subjects with Down's syndrome had larger ear width-to-ear length ratios, and larger angles of the auricle versus the facial midplane than the reference subjects. The three-dimensional symmetry index was significantly larger in the reference subjects and in the older persons. In conclusion, ear dimensions, position and shape significantly differed in subjects with Down's syndrome when compared to sex, age and ethnic group matched controls. Some of the differences were sex and age related.

Mast cells and the inflammatory response to different implanted biomaterials

The biocompatibility of dental materials is a topic of increasing importance for dentists. We investigated the effects of alloys for ceramic crowns and removable prostheses on the skin and lymphoid organs of rats. We used three groups of Sprague Dawley rats: group I as the control, with groups II and III implanted with different biomaterials into subcutaneous pockets. After sacrifice, the rat skin around the implant and the lymph nodes was studied. The tissues of implanted rats were morphologically different from the control animals as they showed a number of mast cells that increased 7 days after the implant with both alloys. These cells decreased 14 days after the implant with alloy for ceramic crowns whereas they were still high 28 days after the implant with alloy for removable prostheses. The findings suggest that both alloys induced different and time-dependent inflammatory reactions. Our findings have importance in the future rational design of biocompatible implantable and blood-contact biomaterials.

Single tooth bite forces in healthy young adults

The assessment of bite forces on healthy single tooth appears essential for a correct quantification of the actual impact of single implant oral rehabilitations. In the present study, a new single tooth strain-gauge bite transducer was used in 52 healthy young adults (36 men, 16 women) with a complete permanent dentition. The influences of tooth position along the dental arch, of side, and of sex, on maximum bite force were assessed by an ANOVA. No significant left-right differences were found. On average, in both sexes the lowest bite force was recorded on the incisors (40-48% of maximum single tooth bite force), the largest force was recorded on the first molar. Bite forces were larger in men than in women (P < 0.002), and increased monotonically along the arch until the first or second permanent molar (P < 0.0001). The present data can be used as reference values for the comparison of dental forces in patients.

Evidence of an influence of asymmetrical occlusal interferences on the activity of the sternocleidomastoid muscle

To investigate the hypothesis of a functional coupling between occlusion and neck muscles, the immediate effect of asymmetrical occlusal interferences on the pattern of contraction of the sternocleidomastoid muscles (SCM) during maximum voluntary clench (MVC) was analysed in 30 healthy subjects. All subjects had a complete and sound permanent dentition, without temporomandibular joint (TMJ) and craniocervical disorders. A 5-s surface electromyogram (EMG) examination of the SCM was performed during (1) MVC in intercuspal position and (2) MVC with a single 200-microm occlusal interference alternatively positioned on teeth 16, 13, 23, 26. All subjects had a symmetrical EMG activity during MVC in intercuspal position. For each subject, SCM potentials were standardized as percentage of the mean potentials recorded during the MVC on natural dentition and the EMG waves of left- and right-side muscles were compared by computing the relevant percentage overlapping coefficient (POC). For each subject, the best and the worst POCs computed during the four MVC tests with occlusal interferences were found and the percentage difference between them was calculated. In the four MVC tests with occlusal interferences, SCM symmetry was very different from that recorded during MVC on natural dentition. The difference between the best and worst POCs computed within each subject was very variable, ranging from 1.52 to 41.57%. In conclusion, when young healthy subjects with a normal occlusion clench on an asymmetrical occlusal interference, they have an altered left-right side pattern of contraction of their SCM. In almost all subjects, a previously symmetrical pattern became asymmetrical.

Immediate effect of a stabilization splint on masticatory muscle activity in temporomandibular disorder patients

Surface electromyography (EMG) allows the quantification of the occlusal equilibrium in dysfunctional patients, for instance in those with temporomandibular disorders (TMD). Fourteen patients (ten women, four men) with internal derangement type I were selected among the TMD patients referred to a private practice in Milan. A stabilization splint with posterior contacts was made for each patient. To verify the static neuromuscular equilibrium of occlusion, EMG activity of left and right temporal and masseter muscles was recorded in all patients and the activity (ratio between the activities of the temporal and masseter muscles) index was computed over a maximum voluntary clench test of 3 s. Muscular waveforms were also analysed by computing a percentage overlapping coefficient (POC, an index of the symmetric distribution of the muscular activity determined by the occlusion). The total electrical activity was measured by calculating the area under the entire muscular waveforms. In all patients EMG was performed just before and immediately after the insertion of the splint and data were compared by paired Student's t-tests. Overall, the splint reduced the electrical activity of the analysed muscles (P < 0.005) and made it more equilibrated both between the left and right side (larger symmetry in the masseter muscle POC, P < 0.05) and between the temporal and masseter muscles (activity index, P < 0.01).

The effect of ethnicity and age on palatal size and shape: a study in a northern Chilean healthy population

Race and ethnicity influence the form of the human craniofacial complex in varying ways. The aim of the present investigation was to quantify the effects of ethnicity (mestizos, Aymara, non-Aymara), age (adolescents and adults), and sex on the form (size and shape) of the hard palate in normal Native American individuals. From the dental casts of 51 individuals with a complete permanent dentition, the x, y, and z coordinates of several standardized palatal landmarks were obtained with a computerized 3-dimensional digitizer. Palatal landmarks were used to derive a mathematical equation for palatal shape in the frontal and sagittal planes. Palatal width and length, frontal and sagittal heights, sagittal slope, and deviation of the raphe from the midline were also calculated. In the Aymara subjects, there was no effect of sex on palatal size, but there was an effect on palatal shape independent of size, especially with respect to male growth. Indeed, female palates apparently did not change their shape between adolescence and adulthood, while male palates increased their posterior "height." Overall, the 3 ethnic groups appeared to possess similar palatal size, with small significant differences. In the adult individuals, ethnicity did not seem to influence palatal shape. In contrast, adolescent males showed differences: non-Aymara subjects had the "highest" palatal shape, Aymara the "lowest," and mestizos an intermediate position. In conclusion, ethnicity does not seem to be a factor of major variability of human hard palate morphology, at least in the present 3 northern Chilean groups, as already found for dental arch shape. Age probably has a larger effect, particularly in the posterior part of the palate, where the eruption of the second and third molars between adolescence and young adulthood may play a role. A further development of the present investigation may involve larger samples of individuals from different ethnic groups.

The effect of sex and age on facial asymmetry in healthy subjects: a cross-sectional study from adolescence to mid-adulthood

PURPOSE

The study assessed the effects of sex and age on 3-dimensional (3D) soft-tissue facial asymmetry.

PATIENTS AND METHODS

The 3D coordinates of selected soft-tissue facial landmarks were digitized on 314 healthy white subjects (40 male and 33 female adolescents, aged 12 to 15 years; 73 female and 89 male young adults, aged 18 to 30 years; and 41 male and 38 female adults, aged 31 to 56 years) by an electromagnetic instrument. Facial asymmetry was quantified by detecting a plane of symmetry and the centers of gravity of the right and left hemifaces and by calculating the distance between the 2 centers of gravity (distance from the symmetry [DFS]). Both absolute (millimeters) and percentage (of the nasion-center of gravity distance) DFS were obtained, as well as the maximum normal asymmetry. The asymmetry of single landmarks was also quantified.

RESULTS

No gender- or age-related differences were found for both absolute and percentage DFS (P > .05). The maximum normal asymmetry was slightly greater in females than in males of corresponding age; within each sex, the largest values were found in the adolescent group. Tragion, gonion, and zygion were the most asymmetric landmarks in all groups (about 10% to 12% of the nasion-facial center of gravity distance), whereas the least asymmetric was endocanthion (4% to 6%).

CONCLUSIONS

A slight soft-tissue facial asymmetry was found in normal subjects. The maximum normal asymmetry could be useful in identifying borderline asymmetric patients.

Harmonic analysis of mandibular form and symmetry with computerized tomographic views

OBJECTIVE

To quantitatively describe the isotropic (ie, orientation independent) morphologic characteristics of a standardized computed tomographic image of the mandible with the use of the elliptic Fourier series.

STUDY DESIGN

Spiral CT scans parallel to the mandibular plane and enclosing both mental foramina were obtained in 17 adults (9 edentulous women, mean age, 75 years; 4 edentulous men, mean age, 68 years; and 4 dentate men, mean age, 30 years). The mandibular outline was traced, digitized, and mathematically reconstructed with the elliptic Fourier series. Mandibular area, shape, and individual symmetry were quantified.

RESULTS

Mandibular area and symmetry were larger in men than in women (P <.05). In men, no effect of edentulousness was observed in either area or symmetry. Mandibular shape seemed to be influenced neither by sex nor by the presence of teeth.

CONCLUSION

Mandibular size and symmetry in the analyzed computed tomographic scan (which included only the mandibular basal bone) seemed to be sex related but independent of the dental status. Mandibular shape did not seem to be modified by sex or edentulousness. Different findings may be obtained in the analysis of a section of the alveolar bone.

Morphometry of the normal human ear: a cross-sectional study from adolescence to mid-adulthood

The objective of this study was to supply information about: (1) normal gender-based dimensions of ears (linear distances and ratios, area); (2) left right symmetry; and (3) growth changes between adolescence and mid-adulthood. The three-dimensional co-ordinates of several soft-tissue landmarks on the ears and face were obtained by an electromagnetic digitizer in 40 male and 33 female adolescents aged 12-15 years. 73 young female and 89 young male adults aged 19-30 years, and 41 male and 38 female adults aged 31-56 years. From the landmarks, paired car width and length were calculated and averaged for age and gender, as well as the relevant ratios, ear areas and angles relative to the facial midline, and indices of left right symmetry. Comparisons were performed by factorial analysis of variance. All ear dimensions were significantly larger in men than in women (P < 0.005). A significant effect of age was found (P < 0.005), with larger values in older individuals. On average, the three-dimensional position of ears was symmetric, with symmetry coefficients ranging between 94 and 96%. Data collected in the present investigation could serve as a database for the quantitative description of human ear morphology during normal adolescent and adult growth.

Size and shape of the human first permanent molar: a Fourier analysis of the occlusal and equatorial outlines

Form can be viewed as a combination of size and shape. Shape refers to the boundary outline independently from its orientation, relation to reference planes, and dimension (or size). Shape and its changes could be quantified by mathematical methods such as the Fourier series. In this investigation, Fourier analysis has been used to quantify the morphologic characteristics (size and shape) of the outline of the occlusal surface and maximum circumference (equator) in 259 normal, healthy human first permanent maxillary and mandibular molars and to assess the effect of sex. Large within-group variability was found in the Fourier coefficients. Both equatorial and occlusal molar areas were on average larger in male than in female homologous teeth, but the difference was statistically significant only for the equatorial areas. The mean ratios between equatorial and occlusal dental areas were independent from arch (maxillary and mandibular), side, or sex. Both equatorial and occlusal outlines of left and right homologous molars within sex and arch were similar, without size and shape differences. Similarly, no sex differences in shape were found in the comparison of homologous teeth. The method used in the present study could supply information about dental shape in both its entirety and local variations. In particular, the method is extremely sensitive to local variations in dental shape, and it could be usefully employed to compare single teeth to a standard.

The use of linear and angular measurements of maxillo-mandibular anteroposterior discrepancies

OBJECTIVES

To extend the assessment of the clinical significance of the measurement of the anteroposterior discrepancy between maxilla and mandible on the bisector of the palatal plane to mandibular plane angle to a large group of randomly selected patients of both sexes, and to verify the correlation of this measurement to well established angular and linear assessments of anteroposterior discrepancy.

DESIGN

Retrospective analysis of pre-treatment lateral cephalometric radiographs.

SETTING AND SAMPLE POPULATION

The Laboratory of Functional Anatomy of the Stomatognathic Apparatus at Milan University, Italy. Three hundred and six orthodontic patients (165 males, 141 females) aged between 6 and 50 years.

EXPERIMENTAL VARIABLE

ANB angle; corrected ANB* angle which compensates for the position of the maxilla and rotation of the mandible relative to the cranial base; Wits appraisal; MM-Wits: linear distance between the projections of A and B points on the bisector of the palatal plane to mandibular plane angle.

RESULTS

The MM-Wits distance was significantly correlated to two angles (ANB and ANB*), as well as to the Wits appraisal. All the correlations performed did not show sex- or age-characteristic patterns. The correlation to the corrected ANB* was the best among the three, with a correlation coefficient of 0.915, MM-Wits (mm) = 1.497 x ANB* (degrees) -6.784. From the correlation, reference values for the new measurement have also been estimated, and found to be between -0.65 and -6.85 mm for skeletal Class I individuals.

CONCLUSION

It is recommended that the diagnosis of orthodontic anomalies should be performed taking into consideration more than a single anteroposterior appraisal.