One-year prevalence and the association between SARS-CoV-2 cycle threshold, comorbidity and outcomes in population of Babol, North of Iran (2020-2021).

Background: The present study aimed to investigate the one-year prevalence of SARS-CoV-2, common comorbidities and demographic information among negative- and positive rRT-PCR in health care workers (HCW), hospitalized and outpatients. Also, the association between SARS-CoV-2 cycle threshold (Ct) and the outcomes of patients were analyzed in Babol, northern Iran. Methods: This large retrospective cross-sectional study was performed between March 2020 and March 2021. The records of 19232 hospitalized, outpatients and HCW suspected to COVID-19 were collected from teaching hospitals in the North of Iran. Results: Out of the 19232 suspected to COVID-19 patients, 7251 (37.7%) had a positive rRT-PCR result; 652 (9%), 4599 (63.4%) and 2000 (27.6%) of those were categorized as HCW, hospitalized and outpatients, respectively. Moreover, between the hospitalized and the outpatient group, 10.2 and 0.8% cases died, whereas no death cases were reported in the HCW. Furthermore, it seems that death rate was significantly different between the three groups of Ct value, the highest mortality in those with Ct between 21 and 30 (group B=7.6%) and the lowest in the group with the highest Ct (between 31 and 40 = 5.5%) (p<0.001). Conclusion: In summary, 37.7% of cases were positive for SARS-CoV-2; of which, 63.4, 27.6 and 9% were hospitalized, outpatients and HCW, respectively. With regard to the mortality rate in hospitalized patients and the significant association with Ct under 20 and 30, it seems that the early detection and the initial quantification of SARS-CoV-2 in the first week of the conflict and therapeutic considerations to reduce the relative load can reduce the mortality rate.

Estimation of Abbreviated Mycophenolic Acid Area Under the Concentration- Time Curve during Stable Post-transplant Period by Limited Sampling Strategy.

BACKGROUND: The Area Under the Concentration-time curve (AUC) of Mycophenolic Acid (MPA), is a valid prognosticator of the risk of rejection and the gold standard in its Therapeutic Drug Monitoring (TDM), over time post-transplantation. OBJECTIVE: This study aimed to investigate MPA pharmacokinetic parameters and develop a Limited Sampling Strategy (LSS) to estimate an abbreviated MPA AUC, in the stable phase post-renal transplantation. METHODS: In this study, 19 patients with normal graft function (glomerular filtration rate >70 ml/min) who fulfilled the inclusion and exclusion criteria were involved. Blood samples at various times were taken in the stable phase after transplantation. MPA plasma concentration was measured by reverse-phase high-performance liquid chromatography. MPA AUC0-12h was calculated using the linear trapezoidal rule. Multiple stepwise regression analysis was used to determine the minimal time points of MPA levels that could be used to yield model equations best fitted to MPA AUC 0-12h. The findings of this study were compared with the results of our previous study, which was done similarly in the early phase post-renal transplantation. RESULTS: The results demonstrated that the MPA-AUC and clearance were not affected over time, but MPA-tmax was significantly lower in the stable phase in comparison with the early phase (P=0.001). The best regression equation for AUC estimation in the stable phase was AUC=9.57*C6+27.238 (r2=0.907). The validation of the method was performed using the jackknife method. The mean prediction error of these models was not different from zero (P > 0.05) and had a high root mean square prediction error (7.91). CONCLUSION: In conclusion, the pharmacokinetics of MPA could be affected by time after transplantation, making it essential to develop a limited sampling strategy as an efficacious approach for therapeutic drug monitoring during the stable post-transplant period.

Bacterial microleakage and post space timing for two endodontic sealers: an in vitro study.

AIM: The effects of immediate versus delayed post space preparation on the apical seal using resin and zinc oxide eugenol (ZOE) sealers were compared by a bacterial leakage model. METHODOLOGY: Eighty-six premolars were randomly assigned to four experimental groups of 20 teeth. Three teeth were assigned to each control group, either positive (filled only with guttapercha) or negative (not obturated but root surfaces completely covered). Obturation was achieved by gutta-percha with resin or gutta-percha with a ZOE sealer and lateral condensation technique. Post space was prepared either immediately or a week later, while the obturated teeth had been stored in 100 percent relative humidity at 37 degrees C. The teeth were inserted into plastic vials and suspended in glass bottles. All teeth were covered with cyanoacrylate and layers of nail varnish but the apical 3 mm and were sterilized using gamma rays. Phenol red lactose broth was inoculated into the vials. Staphylococcus epidermidis was introduced into the root canal access of the teeth. Turbidity of the broth in the vials (discoloration) was evaluated daily for a period of 70 days. The data was analyzed statistically with Pearson Chi Square and two ways with ANOVA at 45 days and 70 days. RESULTS: When the depth of time was considered, the mean time of leakage showed no differences between immediate and delayed preparation for resin AH26 versus ZOE Dorifil at 45 and 70 days (p = 0.37 and p = 0.217, respectively). In 45 days, considering the number of teeth with leakage, there was a significant difference between immediate preparation and delayed preparation in AH26 sealer groups (p = 0.028). No difference was present between immediate and delayed preparation groups for the ZOE sealer groups (p = 0.14). CONCLUSION: According to the results of this study and despite type of sealer, immediate post space preparation did not achieve better sealing than delayed post space preparation. Resin AH26 showed the least leaking teeth in 45 days, but it made no difference in 70 days.

A comparative study of density of obturated root canals by conventional and mechanical lateral condensation techniques.

BACKGROUND: The purpose of this study was to compare the weight of root canal filling material used in a new lateral condensation technique named mechanical lateral condensation (MLC) with that of conventional lateral condensation technique (LC). This new technique uses reciprocal handpiece. METHODS: In this experimental study, 40 human extracted straight canine teeth were used. After crown amputation, root canals were prepared with 18 mm in length. The teeth were randomly divided into four experimental groups; each group was consisting of 10 teeth. The teeth in groups IA and IB were filled by LC technique. The teeth in groups IIA and IIB were filled by MLC technique and using a finger spreader that placed in a reciprocating-action handpiece to laterally condense cold gutta-percha, creating space for accessory cones. All of the roots were weighted before and after obturation and the difference demonstrated the weight of gutta-percha mass. The data were analyzed by t-test. RESULTS: The mean weight for MLC obturations was 10.82 ± 0.025 g compared with 7.37 ± 0.035 g for that of LC technique. The difference was statistically significant (P = 0.001). CONCLUSION: This study showed that MLC technique requires more gutta-percha mass than LC technique.

Comparison of removed dentin thickness with hand and rotary instruments.

INTRODUCTION: The aim of this study was to evaluate the amount of dentine removed after canal preparation using stainless steel (SS) hand instruments or rotary ProFile instruments. MATERIALS AND METHODS: Thirty-six extracted human teeth with root canal curvatures less than 30º were embedded in clear polyester resin. The roots were cut horizontally at apical 2, 4 and 7 mm. Dentin thickness was measured at each section and the sections were accurately reassembled using a muffle. Root canals were randomly prepared by SS hand instruments or rotary ProFile instruments. Root sections were again separated, and the remaining dentin thickness was measured. Mann-Whitney U and t tests were performed for analytic comparison of the results. RESULTS: The thickness of removed dentin was significantly different between the two used methods (P<0.05). Significantly greater amounts of dentin was removed mesially in all sections in hand instrumentation group (P<0.001). CONCLUSION: ProFile rotary instrumentation prepares root canals with a greater conservation of tooth structure.

A comparative study of apical microleakage using the conventional lateral condensation and mechanical lateral condensation techniques.

INTRODUCTION: This study compared apical dye penetration using lateral condensation technique (LC) and LC technique with a reciprocal handpiece (mechanical lateral condensation or MLC) as a new method. MATERIALS AND METHODS: Forty-eight human extracted straight canine teeth were used. After crown amputation, the teeth were randomly divided into four experimental groups of 10 teeth each and two negative and positive control groups of 4 teeth each. The groups were as follows: IA, 10 obturations completed by operator A using the LC technique; Group IB, 10 obturations completed by operator B using the LC technique; Group IIA, 10 obturations completed by operator A using the MLC technique; and Group IIB, 10 obturations completed by operator B using the MLC technique. All roots were placed in 2% methylene blue dye and centrifuged at 3000 rpm for 3 minutes. Following centrifugation, the roots were cut along their long axis and evaluated under a stereomicroscope to measure the depth of dye penetration. RESULTS: A t-test showed that the teeth which were filled by the MLC technique had less dye penetration in comparison with LC technique (P<0.05). CONCLUSION: This in vitro study illustrates that canals obturated with the MLC technique had superior apical seal than canals filled with the LC technique.