Effects of chewing gum on mask contamination

Aims@#The aim of this study was to evaluate whether chewing gum affects mask contamination.@*Methodology and results@#Two groups of participants were requested to wear a mask for 15 min with (experimental group) or without (control group) chewing gum. Then, masks were collected and CFU calculation and 16S rDNA sequencing was performed. We found that temperature, humidity and bacterial CFU inside of the mask significantly increased when wearing a mask while chewing gum. Staphylococcus epidermidis was found in both groups. Staphylococcus aureus, Staphylococcus haemolyticus, Streptococcus oralis, Streptococcus parasanguinis and Bacillus wiedmannii were found in only the experimental group.@*Conclusion, significance and impact of study@#Chewing gum significantly increased the temperature, humidity and bacterial CFU inside the mask. Staphylococcus epidermidis, S. aureus, S. haemolyticus, S. oralis, S. parasanguinis and B. wiedmannii were detected inside the mask after chewing gum.

Schematic of mean thickness distribution on the lateral aspect of the canine frontal sinus as an experimental model of sinus surgery / 대한해부학회지

The dog frontal sinus may represent an alternative model dental implant research; its topographical resemblance to the maxillary sinus renders it a potentially favorable experimental environment. The aim of this study was thus to elucidate the anatomical configuration of the canine frontal sinus and histological characteristics, and to determine whether it could be a new canine experimental model for dental implant research. Twenty-four sides of canine frontal bones were harvested. The distance from the nasion to the emerging point of the lateral aspect of the canine frontal sinus was measured with the aid of Lucion software. The thicknesses of the canine frontal sinus wall were measured, and the two specimens stained with hematoxylin and eosin. The mean distance from the nasion to the emerging point of the lateral aspect of the canine frontal sinus was 16.0 mm. The mean thicknesses of the canine frontal bone at 3, 6, 9, 12, and 15 mm lateral to the midsagittal plane were 2.3, 2.7, 3.2, 3.8, and 3.7 mm, respectively. The canine frontal sinus was lined with pseudostratified ciliated columnar epithelium. These data suggest that the canine frontal sinus is a suitable alternative to the canine maxillary sinus as a model for studying various sinus augmentation protocols.

Anatomical considerations of the superior thyroid artery: its origins, variations, and position relative to the hyoid bone and thyroid cartilage / 대한해부학회지

The aim of this study was to provide accurate anatomical descriptions of the overall anatomy of the superior thyroid artery (STA), its relationship to other structures, and its driving patterns. Detailed dissection was performed on thirty specimens of adult's cadaveric neck specimens and each dissected specimen was carefully measured the following patterns and distances using digital and ruler. The superior thyroid, lingual, and facial arteries arise independently from the external carotid artery (ECA), but can also arise together, as the thyrolingual or linguofacial trunk. We observed that 83.3% of STAs arose independently from the major artery, while 16.7% of the cases arose from thyrolingual or linguofacial trunk. We also measured the distance of STA from its major artery. The origin of the STA from the ECA was 0.9±0.4 mm below the hyoid bone. The STA was 4.4±0.5 mm distal to the midline at the level of the laryngeal prominence and 3.1±0.6 mm distal to the midline at the level of the inferior border of thyroid cartilage. The distance between STA and the midline was similar at the level of the hyoid bone and the thyroid cartilage. Also, when the STA is near the inferior border of the thyroid cartilage, it travels at a steep angle to the midline. This latter point may be particularly important in thyroidectomies. We hope that anatomical information provided here will enhance the success of, and minimize complications in, surgeries that involve STA.

Clinical and anatomical approach using Sihler's staining technique (whole mount nerve stain) / 대한해부학회지

Sihler's staining allows visualization of the nerve distribution within soft tissues without extensive dissection and does not require slide preparation, unlike traditional approaches. This technique can be applied to the mucosa, muscle, and organs that contain myelinated nerve fibers. In particular, Sihler's technique may be considered the best tool for observing nerve distribution within skeletal muscles. The intramuscular distribution pattern of nerves is difficult to observe through manual manipulation due to the gradual tapering of nerves toward the terminal end of muscles, so it should be accompanied by histological studies to establish the finer branches therein. This method provides useful information not only for anatomists but also for physiologists and clinicians. Advanced knowledge of the nerve distribution patterns will be useful for developing guidelines for clinicians who perform operations such as muscle resection, tendon transplantation, and botulinum toxin injection. Furthermore, it is a useful technique to develop neurosurgical techniques and perform electrophysiological experiments. In this review, Sihler's staining technique is described in detail, covering its history, staining protocol, advantages, disadvantages, and possible applications. The application of this technique for determining the arterial distribution pattern is also described additionally in this study.

Anatomic Variation of the Anterior Belly of Digastric Muscle and Positional Relationship between the Posterior Belly of Digastric and Stylohyoid Muscle / 체질인류학회지

The digastric muscle is located in the suprahyoid region which consists of anterior belly, intermediate tendon and posterior belly. This muscle is an important landmark when performing an operation of submental and upper neck region. Previous researches have reported about variations of the anterior and posterior belly of digastric muscle. However, there are few studies about the general morphology of the digastric muscle and the relationship with surrounding muscles. The purpose of this study was to analyze the morphology of the anterior belly of digastric muscle and confirm the topographic relationship between the digastric muscle and the stylohyoid muscle of Korean. Thirty-four cadavers (21 males, 13 females; mean age 65 years; range 24~89 years) were used in this study. The skin, subcutaneous tissues, superficial fascia and platysma were removed and a detailed dissection was performed, with extreme care being taken not to damage underlying the muscles of submental and upper neck region. After the dissections, all specimens were sketched and photographed. In 8 specimens, we observed the accessory bellies of the anterior belly of digastric muscle. We classified the accessory bellies into the crossover type (five specimens, 14.7%) that cross the mandibular raphe and unilateral type (three specimens, 8.82%). The findings resulting from observation of the anatomical relationship between the posterior belly of digastric and stylohyoid muscles, the posterior belly of digastric muscle perforated the stylohyoid muscle in 32 cases (65%) out of 49 sides. This case was subdivided into the belly of the stylohyoid muscle lean to the lateral (twenty-one specimens, 42.9%) or medial side (eleven specimens, 22.4%) of the posterior belly of digastric muscle. In 17 specimens (35%), the stylohyoid muscle existed on the medial side of the posterior belly of digastric muscle.