Clinical crown height changes in adult patients after non-extraction, orthodontic treatment: a retrospective cohort study.

OBJECTIVE: To assess changes in clinical crown height (CCH) in adult orthodontic patients treated by fixed appliances to distalise the molars. DESIGN: Retrospective case series study. SETTING AND PATIENTS: A total of 30 adults with healthy periodontal tissues who received orthodontic treatment at the Department of Orthodontics, Yokohama, Japan and its related orthodontic clinic were assessed. METHODS: CCH was measured as the distance from the gingival margin to the crown plane perpendicular to the tooth axis. Treatment changes of CCH of each tooth were examined on the labial/buccal and lingual/palatal side. RESULTS: In the upper dentition, on the labial/buccal side, the CCH of the lateral incisors, canines, first premolars, first molars and second molars were increased significantly (P < 0.01), with a median value of 0.41 mm, 0.43 mm, 0.28 mm, 0.43 mm and 0.55 mm, respectively. In contrast on the palatal side, the CCH of the central incisors, first molars, and second molars decreased significantly (P < 0.01), with a median value of -0.41 mm, -0.30 mm and -0.20 mm, respectively. In the lower dentition on the labial/buccal side, the CCH of the first premolars, second premolars and first molars were increased significantly, with a median value of 0.39 mm (P < 0.01), 0.43 mm (P < 0.01) and 0.19 mm (P < 0.05), respectively. The second molars exhibited a significant decrease in CCH with a median value of -0.26 mm (P < 0.05). On the lingual side, the CCH of the central incisors, lateral incisors, canines, first premolars, second premolars and first molars were increased significantly (P < 0.01), with a median value of 0.28 mm, 0.22 mm, 0.31 mm, 0.37 mm, 0.26 mm and 0.28 mm, respectively. CONCLUSION: Significant differences were observed in CCH before and after treatment for many teeth, the average change was less than 0.5 mm. The impact on the long-term health of the periodontal tissue is unknown.

Prevalence of saliva immunoglobulin A antibodies reactive with severe acute respiratory syndrome coronavirus 2 among Japanese people unexposed to the virus.

While the COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a threat to public health as the number of cases and COVID-19-related deaths are increasing worldwide, the incidence of the virus infection is extremely low in Japan compared with many other countries. To explain this uncommon phenomenon, we investigated the prevalence of naturally occurring ("natural") antibodies, focusing on those of the secretory immunoglobulin A (sIgA) form, reactive with SARS-CoV-2 among Japanese people. One hundred and eighty healthy Japanese volunteers of a wide range of age who had been considered to be unexposed to SARS-CoV-2 participated in this study. Saliva samples and blood samples were collected from all of the 180 participants and 139 adults (aged ≥ 20 years) included therein, respectively. The determination of saliva IgA antibodies, mostly comprising sIgA antibodies, as well as serum IgA and immunoglobulin G antibodies, reactive with the receptor binding domain of the SARS-CoV-2 spike-1 subunit proteins was conducted using an enzyme-linked immunosorbent assay. The major findings were that 52.78% (95% confidence interval, 45.21%-60.25%) of the individuals who had not been exposed to SARS-CoV-2 were positive for saliva IgA antibodies with a wide range of levels between 0.002 and 3.272 ng/mL, and that there may be a negative trend in positivity for the antibodies according to age. As we had expected, a frequent occurrence of assumable "natural" sIgA antibodies reactive with SARS-CoV-2 among the studied Japanese participant population was observed.

Association between saliva PSA and serum PSA in conditions with prostate adenocarcinoma.

In recent years, saliva samples have attracted attention as specimens, which may be used for cancer diagnosis. Prostate-specific antigen (PSA) is the most useful tumor marker for prostate adenocarcinoma (PA). We examined whether there is an association between saliva PSA and serum PSA in patients with PA using enzyme-linked immunosorbent assay. Human subjects were classified into two groups: a low-serum PSA concentration group (n = 20) (<2.5 ng/mL) and a high-serum PSA concentration group with high risk of recurrence or metastasis (n = 11) (≤2.5 ng/mL). There were significant differences in saliva PSA concentration between these groups (p < 0.05). Saliva PSA concentration correlated very well with serum PSA concentration in the high-serum PSA concentration group (γ = 0.910, p < 0.001) using Spearman's rank test, but no correlation in the low-serum PSA concentration group. This result suggests that saliva PSA is associated with blood PSA in patients with recurrent or metastatic PA and may, therefore, be a useful PA biomarker.

Bruxism affects stress responses in stressed rats.

It has been proposed that suppression of stress-related emotional responses leads to the simultaneous activation of both sympathetic and parasympathetic divisions of the autonomic nervous system (ANS) and that the expression of these emotional states has a protective effect against ulcerogenesis. In the present study, we investigated whether stress-induced bruxism activity (SBA) has a physiological effect of on the stress-induced changes of the stomach, thymus, and spleen as well as blood leukocytes, cortisol, and adrenaline. This study demonstrated that SBA attenuated the stress-induced ulcer genesis as well as degenerative changes of thymus and spleen. SBA also attenuated increases of adrenaline, cortisol, and neutrophils in the blood. In conclusion, expression of aggression through SBA during stress exposure attenuates both stress-induced ANS response, including gastric ulcer formation.