The immediate effect of alternate rapid maxillary expansions and constrictions on the alveolus: a retrospective cone beam computed tomography study

Abstract Background Rapid maxillary expansion reduced the expander’s anchor teeth buccal alveolar bone thickness. However, the effects of alternate rapid maxillary expansions and constrictions (Alt-RAMEC) on the expander’s anchor teeth alveolar thickness has not been assessed. The purpose of this retrospective study was to evaluate the effects of Alt-RAMEC on the alveolus surrounding the anchor teeth of a double-hinged expander. Methods Twenty-six individuals, including 12 males (11.5 ± 1.00 years) and 14 females (11.5 ± 0.90 years), who had double-hinged expander for 7 weeks of Alt-RAMEC and then 3 months of maxillary protraction, were included. Their cone beam computed tomography (CBCT) images taken 3–6 months before treatment (T0) and after 7 week of Alt-RAMEC (T1), were studied for the buccal alveolar bone thickness (BABT) and palatal alveolar bone thickness (PABT) of the expander’s anchor teeth (first molars and first and second premolars) in four axial sections. The intra-class correlation coefficient, Dahlberg’s formula, and paired t tests were used to analyze the method errors, and the intra-group changes of the BABT and PABT at T0-T1 were analyzed by paired t test (p < 0.05). Results The 7 weeks of Alt-RAMEC significantly reduced the BABT of the expander’s anterior anchor teeth (0.54~ 70 mm, p < 0.05) and at the cervical region (0.14~ 0.25 mm, p < 0.05), but not at the apical region of the expander’s posterior anchor teeth. The reduction of BABT by 7 weeks of Alt-RAMEC was within the scope of the initial BABT. On the opposite, the Alt-RAMEC significantly (p < 0.05) increased the PABT in the anterior anchor teeth and the cervical region of posterior anchor teeth. Conclusions A 7-week protocol of Alt-RAMEC with double-hinged expander for maxillary protraction might reduce the buccal alveolar bone thickness of the expander’s anchor teeth, although the reduction is within the scope of initial alveolar thickness of the expander’s anchor teeth

Major Adverse Cardiovascular Events in Treated Periodontitis: A Population-Based Follow-Up Study from Taiwan.

The aim of the present study was to identify the long-term major adverse cardiovascular events (MACE) in treated periodontitis patients in Taiwan.From the National Health Insurance Research Database (2001-2010), adult patients (≥ 18 years) with treated periodontitis were identified. Comparison was made between patients with mild form and severe form of treated periodontitis after propensity score matching. The primary end point was the incidence of MACE.A total of 32,504 adult patients with treated periodontitis were identified between 2001 and 2010. After propensity score matching, 27,146 patients were preserved for comparison, including 13,573 patients with mild form and 13,573 patients with severe form of treated periodontitis. During follow-up, 728 individuals in mild treated periodontitis group and 1,206 individuals in severe treated periodontitis group had at least 1 MACE event. After adjustment for gender, hyperlipidemia, hypertension and diabetes mellitus, severe treated periodontitis was associated with a mildly but significantly increased risk of MACE among older patients > 60 years of age (incidence rate ratio, 1.26; 95% confidence interval, 1.08-1.46). No association was found among younger patients ≤ 60 years of age.Severe form of treated periodontitis was associated with an increased risk of MACE among older Taiwanese patients, but not among younger Taiwanese patients. We should put more efforts on the improvement of periodontal health to prevent further MACE

Incidence rate ratio (IRR) for MACE by multivariate competing risk regression model in treated periodontitis (TP) in Taiwan from 2001 to 2010.

<p>*Incidence rate ratio by multivariate competing risk regression model was adjusted for sex, hyperlipidemia, hypertension, diabetes and TP stage; MACE, major adverse cardiovascular events; CI, confidence interval.</p><p>Incidence rate ratio (IRR) for MACE by multivariate competing risk regression model in treated periodontitis (TP) in Taiwan from 2001 to 2010.</p

Selection of study subjects and identification of major adverse cardiovascular events (MACE) in treated periodontitis in Taiwan from 2001 to 2010.

<p>Selection of study subjects and identification of major adverse cardiovascular events (MACE) in treated periodontitis in Taiwan from 2001 to 2010.</p

The cumulative incidence of major adverse cardiovascular events (MACE) associated with mild and severe treated periodontitis (TP).

<p>A. The cumulative incidence of MACE among younger patients (age ≤ 60 years old); B. The cumulative incidence of MACE among older patients (age > 60 years old).</p

The incidence of MACE among different demographic and clinical groups by types of MACE in treated periodontitis (TP) in Taiwan from 2001 to 2010.

<p>Values are numbers of events (incidence rate, i.e., 100,000 patients per year); MACE, major adverse cardiovascular events; MI, myocardial infarct; PCI, percutaneous coronary intervention; CABG, coronary artery bypass grafting; HF, heart failure; CVA, cerebrovascular accident; MD, malignant dysrhythmia; Throm, thrombolysis; CS, cardiac shock.</p><p>The incidence of MACE among different demographic and clinical groups by types of MACE in treated periodontitis (TP) in Taiwan from 2001 to 2010.</p

Effect of Butyrate on Collagen Expression, Cell Viability, Cell Cycle Progression and Related Proteins Expression of MG-63 Osteoblastic Cells

<div><p>Aims</p><p>Butyric acid is one major metabolic product generated by anaerobic Gram-negative bacteria of periodontal and root canal infection. Butyric acid affects the activity of periodontal cells such as osteoblasts. The purposes of this study were to investigate the effects of butyrate on MG-63 osteoblasts.</p><p>Methods</p><p>MG-63 cells were exposed to butyrate and cell viability was estimated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The mRNA and protein expression of type I collagen and cell cycle-related proteins were measured by reverse-transcriptase polymerase chain reaction (RT-PCR), western blotting or immunofluorescent staining. Cellular production of reactive oxygen species (ROS) was analyzed by 2',7'-dichlorofluorescein (DCF) fluorescence flow cytometry.</p><p>Results</p><p>Exposure to butyrate suppressed cell proliferation, and induced G2/M (8 and 16 mM) cell cycle arrest of MG-63 cells. Some cell apoptosis was noted. The mRNA expression of cdc2 and cyclin-B1 decreased after exposure to butyrate. The protein expression of type I collagen, cdc2 and cyclin B1 were decreased, whereas the expression of p21, p27 and p57 was stimulated. Under the treatment of butyrate, ROS production in MG-63 cells markedly increased.</p><p>Conclusions</p><p>The secretion of butyric acid by periodontal and root canal microorganisms may inhibit bone cell growth and matrix turnover. This is possibly due to induction of cell cycle arrest and ROS generation and inhibition of collagen expression. These results suggest the involvement of butyric acid in the pathogenesis of periodontal and periapical tissue destruction by impairing bone healing responses.</p></div

Effect of butyrate (1–16 mM) on cellular ROS level of MG-63 cells.

<p>One representative histogram of DCF fluorescence in control MG-63 cell and MG-63 cells exposed to 1–16 mM butyrate. An increase in DCF fluorescence was noted, indicating an increase of ROS production. *denotes statistically significant difference when compared with untreated control (as 100) (P < 0.05).</p

Effect of butyrate on the cell viability of MG-63 cells.

<p>MG63 cells were exposed to various concentrations of butyrate for 5 days. *denotes significant difference when compared with control (P < 0.05).</p

Effect of butyrate on cell cycle distribution of MG-63 cells.

<p><b>(A)</b> The effect of different concentration of butyrate (0–16 mM) on G0/G1, G2/M, and S phase of MG-63 cells (5 x 10⁵ cells/well) after 24 hrs exposure time. *denotes significant difference when compared with control (P < 0.05). <b>(B)</b> The effect of different concentration of butyrate (0–16 mM) on sub G0/G1 population of MG-63 cells (5 x 10⁵ cells/well) after 24 hrs. *denotes significant difference when compared with control (P < 0.05).</p