Efficacy of Local Minocycline Agents in Treating Peri-Implantitis: An Experimental In Vivo Study in Beagle Dogs.

BACKGROUND: Local delivery agents (LDA) have the advantage of delivering the antibiotics at high concentrations to the targeted sites. However, the constant flow of gingival crevicular fluids and saliva may restrict their efficacy. Therefore, the drug sustainability and pharmacodynamic properties of any proposed LDA should be evaluated. METHODS: Four dental implants were placed unilaterally in the edentulous mandible of six beagle dogs. Peri-implantitis were experimentally induced using silk-ligatures. Each implant was randomly allocated to receive one of the following four treatments: (i) MC (Chitosan-alginate (CA) minocycline), (ii) MP (CA-without minocycline), (iii) PG (Polyacrylate-glycerin minocycline), and (iv) Control (mechanical debridement only). Mechanical therapies and LDAs were administered into the gingival sulcus two times at a 4-week interval. Drug sustainability as well as clinical, radiographical, and immunohistochemical (IHC) analyses were conducted to evaluate the efficacies of treatments. RESULTS: Reduced mean probing depth was observed in all of the test groups after the second delivery. A minimal marginal bone level change was observed during the treatment period (MP (-0.06 ± 0.53 mm) to PG (-0.25 ± 0.42 mm)). The distribution of IHC cell marker analysis of all targeted antibodies ranged from 6.34% to 11.33%. All treatment outcomes between the test groups were comparable. A prolonged retention of LDA was observed from CA microspheres (MC and MP) at both administrations (p < 0.017) and prolonged sustainability of bacteriostatic effect was observed from MC compared to PG after the second administration (p < 0.05). CONCLUSIONS: Prolonged retention of CA microspheres was observed and the longer bacteriostatic effect was observed from the MC group. Mechanical debridement with adjunct LDA therapy may impede peri-implantitis progression, however, prolonged drug action did not lead to improved treatment outcome.

Soft Tissue Dimensions Following Tooth Extraction in the Posterior Maxilla: A Randomized Clinical Trial Comparing Alveolar Ridge Preservation to Spontaneous Healing.

BACKGROUND: To assess the soft tissue dimension following tooth extraction and alveolar ridge preservation in the posterior maxilla compared to spontaneous healing. METHODS: Thirty-five patients randomly assigned to alveolar ridge preservation (ARP) and spontaneous healing (SH) after maxillary molar extraction. The crestal, buccal, and palatal gingival thickness at 6 months was measured around virtually placed implant fixtures using superimposed cone-beam computed tomography and intraoral scan taken at 6 months. Buccal mucogingival junction (MGJ) level change over 6 months was estimated using intraoral scans obtained at suture-removal and 6 months. RESULTS: The crestal gingiva was significantly thinner in group ARP (-1.16 mm) compared to group SH (p < 0.05). The buccal and palatal gingiva was significantly thinner at the implant shoulder (IS) level in group ARP (buccal: -0.75 mm; palatal: -0.85 mm) compared to group SH (p < 0.05). The thickness at 2 mm below the IS of both sides and the buccal MGJ level change were similar in both groups (p > 0.05). CONCLUSIONS: ARP in the posterior maxilla resulted in a thinner soft tissue on top of and at the prospective level of the implant shoulder at 6 months. The buccal MGJ level changed minimal for 6 months in both groups.

Locally Applied Slow-Release of Minocycline Microspheres in the Treatment of Peri-Implant Mucositis: An Experimental In Vivo Study.

BACKGROUND: The objective of this is preclinical investigation was to evaluate the differential drug sustainability and pharmacodynamic properties of two local minocycline microsphere carriers: chitosan-coated alginate (CA) and poly(meth)acrylate-glycerin (PG). METHODS: Four dental implants were placed unilaterally in the edentulous mandible of six beagle dogs. Each implant was randomly assigned to receive one of the following four treatments: (i) CA (CA-based minocycline), (ii) placebo (CA substrate without minocycline), (iii) PG (PG-based minocycline) and (iv) control (mechanical debridement only). After inducing peri-implant mucositis, the randomly assigned treatments were administered into the gingival sulcus twice at a 4-week interval using a plastic-tipped syringe. Drug sustainability and pharmacodynamic (clinical, radiographical and cell marker intensity) evaluations were performed after each administration. RESULTS: The CA microspheres remained longer around the healing abutment compared to the PG microspheres at both administrations and a longer bacteriostatic effect was observed from CA (7.0 ± 5.7 days) compared to PG (1.2 ± 2.6 days). The efficacy of the applied therapies based on clinical, radiographical and histological analyses were comparable across all treatment groups. CONCLUSIONS: CA microspheres showed longer carrier and bacteriostatic effect sustainability when compared to PG microspheres, however, longer drug sustainability did not lead to improved treatment outcomes.

Long-term assessment of periodontal disease progression after surgical or non-surgical treatment: a systematic review.

The primary aim of this systematic review was to assess the evidence on periodontal disease progression after treatment in patients receiving supportive periodontal therapy (SPT) and to identify predictors of clinical attachment level (CAL) loss. A protocol was developed to answer the following focused question: In adult patients treated for periodontitis, what is the disease progression in terms of CAL loss after surgical or non-surgical treatment? Randomized controlled clinical trials, prospective cohort studies, and longitudinal observational human studies with a minimum of 5 years of follow-up after surgical or non-surgical treatment that reported CAL and probing depth changes were selected. Seventeen publications reporting data from 14 investigations were included. Data from 964 patients with a follow-up range of 5-15 years was evaluated. When the CAL at the latest follow-up was compared to the CAL after active periodontal therapy, 10 of the included studies reported an overall mean CAL loss of ≤0.5 mm, 3 studies reported a mean CAL loss of 0.5-1 mm, and 4 studies reported a mean CAL loss of >1 mm. Based on 7 publications, the percentage of sites showing a CAL loss of ≥2 mm varied from 3% to 20%, and a high percentage of sites with CAL loss was associated with poor oral hygiene, smoking, and poor compliance with SPT. The outcomes after periodontal therapy remained stable over time. Disease progression occurred in a reduced number of sites and patients, mostly associated with poor oral hygiene, poor compliance with SPT, and smoking.

An alternative methodology for planning baggage carousel capacity expansion: A case study of Incheon International Airport.

Intensifying competition for air transportation passengers has led airports to research optimal designs and determine the infrastructure expansion capacities of their terminals. As a result, many researchers have studied this subject from a variety of perspectives. In this study, we propose an alternative methodology of determining the expansion of baggage carousel capacity over a series of steps that includes both a simulation and a cost-benefit analysis. The methodology consists of three stages. In the first stage, we forecast the volume of arriving passengers (excluding transfer passengers) and aircraft traffic with an autoregressive integrated moving average (ARIMA) model. Next, we conduct an elaborate analysis to estimate passenger delay using a discrete event simulation model in which we consider the conveyor load and the baggage carousel allocation to aircraft rates. Finally, we determine a plan to expand baggage carousel capacity that accounts for expansion costs and passenger benefits. Construction and conveyor costs were applied to expansion costs, and capacity expansion leads to passenger benefits due to reduced waiting time. Using a real case with 23 candidate baggage carousels at Incheon International Airport during 2013-2015, our experiments demonstrate the strength of the proposed methodology in planning appropriate capacity expansion that reflect the operational flow of passengers within the airport based on the future trend of passenger demand. In particular, our results show that carousel no. 18 should be expanded during the first quarter of 2013, carousels no. 17 and no. 19 should be expanded in 2014, and carousel no. 5 should be expanded in 2015 to obtain optimal benefit-cost ratios of 1.65, 1.79, and 1.76 for each year, respectively.

Comparison of emergence times with different fresh gas flow rates following desflurane anaesthesia.

OBJECTIVE: To investigate emergence times with different fresh gas flow rates, following desflurane anaesthesia. METHODS: Patients undergoing surgery with desflurane anaesthesia were randomly assigned to receive fresh gas flow rates of 100% oxygen during emergence of 2 l/min (group D2), 4 l/min (group D4) or 6 l/min (group D6). Time to eye opening, spontaneous movement and extubation (emergence time) were assessed after desflurane discontinuation. The end-tidal concentration of desflurane and bispectral index were recorded at each of these timepoints. RESULTS: A total of 105 patients were included in the study, with 35 in each of the three groups. Mean times to extubation were 17.6 min, 9.9 min and 9.1 min in groups D2, D4 and D6, respectively. Times to eye opening, spontaneous movement and extubation in group D2 were significantly longer than in groups D4 and D6. CONCLUSIONS: These results suggest that there is the potential to predict emergence time based on fresh gas flow rate following desflurane anaesthesia. It should therefore be possible to use a low-flow technique during the emergence period, in addition to the maintenance period, without delaying recovery if the inhaled anaesthetic is stopped at the predicted time before the end of surgery.

A comparison of the accuracy of ulnar versus median nerve stimulation for neuromuscular monitoring.

BACKGROUND: Inexperienced anesthesiologists are frequently unclear as to whether to stimulate the ulnar or median nerve to monitor the adductor pollicis. The primary purpose of this study was to determine whether monitoring the adductor pollicis by positioning the stimulating electrodes over the median nerve is an acceptable alternative to applying electrodes over the ulnar nerve. METHODS: In 20 patients anesthetized with propofol and remifentanil, one pair of stimulating electrodes was positioned over the ulnar nerve. A second pair was placed over the median nerve on the other hand. The acceleromyographic response was monitored on both hands. Rocuronium 0.6 mg/kg was administered. Single twitch (ST) and train-of-four (TOF) stimulations were applied alternatively to both sites. RESULTS: None of the patients showed a twitch response at either site after injection of rocuronium. There were no differences in the mean supramaximal threshold, mean initial TOF ratio, or mean initial ST ratio between the two sites. Bland-Altman analysis revealed a bias (limit of agreement) in the TOF and ST ratios over the median nerve of 7% (± 31%) and 26% (± 73%), respectively, as compared with the ulnar nerve. The median nerve TOF ratio was overestimated by 16.2%, as compared with that of the ulnar nerve value, and the median nerve ST ratio was overestimated by 72.9%, as compared to that of the ulnar nerve. CONCLUSIONS: The ulnar and median nerves cannot be used interchangeably for accurate neuromuscular monitoring.

Rocuronium-induced neuromuscular block after long pretreatment of clonidine in rabbits.

BACKGROUND: Clonidine, an α-2 adrenergic agonist, is used in the perioperative period and in intensive care for the management of hypertension. The in vivo and in vitro effects of clonidine on the actions of nondepolarizing neuromuscular blocking drugs are conflicting. We evaluated the potency and time course of rocuronium-induced neuromuscular block after prolonged pretreatment with clonidine in rabbits. METHODS: Sixty rabbits were randomly assigned to three groups; control (C) group: normal saline 0.1 ml/kg daily subcutaneous for 6 weeks; S3 group: clonidine 4 µg/kg daily subcutaneous for 3 weeks; S6 group: clonidine 4 µg/kg daily subcutaneous for 6 weeks. The dose-response relations of rocuronium were tested in 30 rabbits (10 from each of the three groups) during ketamine-thiopental anesthesia, while the time course of rocuronium 0.6 mg/kg was examined in 10 rabbits each from the three groups. RESULTS: There was no difference in mean arterial pressure and pulse rate among the experimental groups. The calculated ED(50) for rocuronium decreased significantly from 64.1 µg/kg (C group) to 50.3 µg/kg (S3 group) and 47.8µg/kg (S6 group) (P < 0.001). There was no difference in the onset and the recovery times after rocuronium. CONCLUSIONS: Rocuronium after pretreatment with clonidine for three or six weeks may have an increased effect, but no difference in the duration of action compared with control group.

Decreased serum brain-derived neurotrophic factor levels in elderly korean with dementia.

OBJECTIVE: The primary purpose of this study was to investigate the differences in the serum brain-derived neurotrophic factor (BDNF) level between elderly Korean people over 65 years with and without dementia. METHODS: 171 individuals over 65 years were enrolled in this study. Screening for cognitive impairments was carried out using the Mini-Mental Status Examination-Korean version (MMSE-KC). One hundred thirty-two subjects scored below 1.5 standard deviations (SD) of the mean MMSE-KC score, and these were evaluated using the Consortium to Establish a Registry for Alzheimer's Disease, Korean version (CERAD-K) and the Geriatric Depression Scale (GDS). The Clinical Dementia Rating Scale (CDRS) and the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) diagnostic criteria were used for further evaluation. Subjects with a CDRS score of 1 or higher were classified as having Alzheimer's disease (AD), and subjects with a CDRS score of 0.5 were classified as having a mild cognitive impairment (MCI). Subjects with a CDRS score of 0 were classified as having aging-associated cognitive decline (AACD). Serum BDNF levels were analyzed using the enzyme-linked immunosorbent assay (ELISA) method. RESULTS: The serum BDNF levels were significantly lower in the subjects with MCI and AD compared with the healthy controls (p<0.01). A significant correlation was found between the total MMSE-KC score and serum BDNF level (r=0.295; p<0.01). However, no significant correlation was observed between the severity of MMSE-KC and the total GDS score. A significant difference was found in the total score of GDS between the AACD group and subjects with AD (p<0.05). CONCLUSION: This study suggested that BDNF might be involved in the pathophysiology of cognitive decline in elderly people.

Prevalence of Alzheimer's dementia and its risk factors in community-dwelling elderly koreans.

OBJECTIVE: We estimated the prevalence of Alzheimer's dementia (AD) and mild cognitive impairment (MCI) and their risk factors in an urban community setting, focusing especially on metabolic syndrome. METHODS: A two-phase investigation based on a door-to-door survey was performed. In Phase I, we administered the Korean version of the Mini-Mental State Examination (MMSE-KC) of the Consortium to Establish a Registry for Alzheimer's disease (CERAD-K). Assessment Packet and the Korean version of the Geriatric Depression Scales (GDS-K) to all 706 participants aged 65 years or older. In Phase II of the study, 175 persons underwent physical and neurological examinations according to the protocol of the CERAD-K clinical assessment battery [CERAD-K (C)] and the neuropsychological assessment battery [CERAD-K (N)]. We also examined the association between cognitive decline and metabolic syndrome. AD and MCI were defined using the DSM-IV-TR criteria and the Clinical Dementia Rating (CDR) scales. RESULTS: The mean age (+/-SD) of the subjects was 74.3+/-16.7 years and the ratio of males to females was 53.2 to 46.8. The prevalence of Alzheimer's dementia was 9.0%, while that of MCI was 32.9%. Old age and lower educational level had significant associations with cognitive decline in the elderly, but gender, years of alcohol intake or smoking, and metabolic syndrome were not associated with AD or MCI. CONCLUSION: In this study, metabolic syndrome was not associated with Alzheimer's AD or MCI. Information regarding an association between Alzheimer's dementia and metabolic syndrome in this study will be helpful in formulating future public health policy and prevention strategies in Korea.

Clinical results of endoscopic dacryocystorhinostomy using a microdebrider.

PURPOSE: The success rate of endoscopic dacryocystorhinostomy has been increasing with the development of better instruments and techniques. We conducted this study to evaluate the clinical results of endoscopic dacryocystorhinostomy using a Microdebrider, which has also been used for functional endoscopic sinus surgery. METHODS: We selected 76 patients (with a total of 84 affected eyes) who had been diagnosed with a nasolacrimal duct obstruction. These patients underwent an endoscopic dacryocystorhinostomy using a Microdebrider, which removed both nasal mucosa and lacrimal sac mucosa and also trimmed the margins of the ostotomy site. We assessed patients' outcomes on an anatomical basis using a dye test and endoscopy, which were used to define the anatomical success. We also arbitrarily defined functional success as whether the subjective epiphora was absent. At a four to 18 month follow-up, we monitored the clinical course to examine any recurrent episodes. RESULTS: The symptoms were alleviated in 72 eyes, with a primary success rate of 85.7%. On nasal endoscopy, a functional failure was seen in four eyes. In these four eyes, the orifice was narrowed by the presence of either granulation tissue or conjunctivochalasis. By contrast, surgical outcomes were the anatomical failure in eight eyes. In these eight eyes, the orifice was obstructed by the presence of granulation tissue as well as the adhesion of nasal mucosa. CONCLUSIONS: Endoscopic dacryocystorhinostomy using a Microdebrider enabled us to make the large fistula while minimizing the damage of adjacent tissue. It might be the recommended surgery that reduces the complications and enhances the success rate.

Characterization of homologous defective interfering RNA during persistent infection of Vero cells with Japanese encephalitis virus.

It has been suggested that defective interfering (DI) RNA contributes to the persistence of Japanese en-cephalitis virus (JEV). In this study, we characterized molecular and biological aspects of the DI RNA and its relation to viral persistence. We identified a homolo-gous DI virus intimately associated with JEV persis-tence in Vero cells. The production of DI RNA during undiluted serial passages of JEV coincided with the appearance of cells refractory to acute infection with JEV. We also established a Vero cell clone with a per-sistent JEV infection in which the DI RNA co-replicated efficiently at the expense of helper virus. The infectious virus yield of the clone fluctuated dur-ing its growth depending upon the amount of DI RNA accumulated in the previous replication cycle. Identifi-cation of the corresponding negative-sense RNA of the DI RNA indicated that the DI RNA functioned as a replication unit. Most of the DI RNA molecules re-tained their open reading frames despite a large dele-tion, encompassing most of the prM, the entire E, and the 5' half of the NS1 gene. Taken together, these ob-servations suggest that the generation of homologous DI RNA during successive JEV acute infections in Vero cells probably participates actively in persistent JEV infection.