Tetragonal zirconia polycrystals (TZP) has drawn attention as a potential alternative to titanium (Ti) in dental implant treatment, as it minimizes both allergic reactions and esthetic problems. It is also important for dental implants to maintain plaque-free surfaces to prevent peri-implantitis. The purpose of this study was to investigate in vitro adherence of periodontopathic bacteria to TZP comparing with Ti. Periodontopathic bacteria were cultured on polished discs of two kinds of TZP, and Ti as a control. After incubation, the numbers of adherent bacteria were estimated. No significant differences among specimens were observed in the initial attachment, although a decrease was observed in initial attachment to saliva-coated specimens. In the bacterial colonization, no significant differences were recognized among specimens. The adherence of the periodontopathic bacteria on TZP was similar to that on Ti. These results suggest that a strategy is required for inhibition of the bacterial adherence to TZP.

No abstract

BackgroundPeritoneal dialysis (PD)-associated infection caused by Mycobacterium spp. is rare. Mycobacterium abscessus is one of the most resistant acid-fast bacteria, and treatment is also the most difficult and refractory. Thus, we report a case of PD-associated peritonitis caused by Mycobacterium abscessus that was difficult to treat and led to PD failure.Case presentationWe recently encountered a 56-year-old man who developed PD-associated infection. We initially suspected exit-site infection (ESI) and tunnel infection (TI) caused by methicillin-resistant coagulase-negative Staphylococcus. However, antibiotic therapy did not provide any significant improvement. Thus, we performed simultaneous removal and reinsertion of a PD catheter at a new exit site. The patient subsequently developed peritonitis and Mycobacterium abscessus was detected in the peritoneal effluent. Thus, the reinserted catheter was removed, hemodialysis was started, and the patient was eventually discharged.ConclusionsIn cases of refractory ESI or TI, it is important to consider non-tuberculous mycobacteria as the potentially causative organism. Even if acid-fast bacterial staining is negative or not performed, detection of Gram-negative bacillus may lead to suspicion and early identification of Mycobacterium spp. In PD-associated infection by Mycobacterium abscessus, catheter removal is necessary in many cases. Simultaneous removal and reinsertion of the catheter is not recommended, even in cases of ESI or TI. Reinsertion should only be attempted after complete resolution of peritoneal symptoms. After removal of the catheter, careful follow-up is necessary, paying attention to complications such as wound infection, peritonitis, and ileus. In addition, the selection and treatment period of antibiotics in PD-associated infection by Mycobacterium abscessus remains unclear, and it is an important topic for future discussion.

BackgroundThis study aimed to evaluate, longitudinally, the outcome of periodontal regenerative therapy using a deproteinized bovine bone mineral (DBBM) in combination with a collagen barrier (CB) for the treatment of intrabony defects.ResultsPatients with chronic periodontitis who have completed initial periodontal therapy participated in this study. They had at least one 2- or 3-wall intrabony periodontal defect of ≥3 mm in depth. During surgery, defects were filled with DBBM and covered with CB. Ten patients completed 2.5-year reevaluation. At baseline, mean clinical attachment level (CAL) of the treated site was 8.0 mm and mean probing depth (PD) was 7.5 mm. Mean depth of intrabony component was 4.6 mm. Mean gains in CAL at 6 months and 2.5 years were 2.8 ± 1.0 and 1.4 ± 1.5 mm, respectively, both showing a significant improvement from baseline. CAL gains at 1 and 2.5 years were significantly reduced from that at 6 months. A significant improvement in PD was also noted: mean reductions in PD at 6 months and 2.5 years were 4.0 ± 0.8 and 3.2 ± 0.8 mm, respectively.ConclusionsThe combination therapy using DBBM and CB yielded statistically significant effects such as CAL gain and PD reduction, up to 2.5 years in the treatment of intrabony defects. However, the trend for decrease in CAL gain over time calls for the need for careful maintenance care.

The prevalence of chronic kidney disease (CKD) as well as Alzheimer's disease (AD) increases with age. With the aging of the population in Japan, there is an increasing likelihood that patients with CKD will receive donepezil hydrochloride (DPZ), an antidementia drug, in the near future. Nevertheless, there have been few reports on how to use DPZ in patients with severe CKD. We report on 2 CKD stage 5 patients who received DPZ under different prescriptions. In case 1, 3 mg/day of DPZ was initially administered for 4 months, after which the dose was increased to 5 mg/day. In case 2, 5 mg was administered twice a week. The plasma concentration of DPZ was measured and the effectiveness was assessed using the Mini-Mental Health State Examination and the Hasegawa Dementia Rating Scale. We found that (1) only a slight increase in the plasma concentration of DPZ was observed with a dose of 3 mg daily, (2) there was a significant increase in the plasma concentration with a dose of 5 mg daily, and (3) when 5 mg of DPZ was administered twice a week, the plasma concentration did not differ significantly from healthy controls who had received 5 mg daily. Although cognitive function was improved best when the 5-mg dose was administered daily with no apparent side effects, the plasma concentration came close to reaching a toxic level at this dose. Careful follow-up may be essential when DPZ is used at 5 mg/day or greater in severe CKD patients.