Implant survival and patient satisfaction in completely edentulous patients with immediate placement of implants: a retrospective study.

BACKGROUND: This study evaluated full-arch rehabilitation of patients with immediately placed implants in terms of the cumulative implant survival rate, risk factors for implant failure, and patient satisfaction. METHODS: Time-to-event data of 52 completely edentulous jaws (370 implants) were collected using retrospective clinical chart review for the time period from 2008 to 2014. A conventional two stage approach for surgery was adopted to immediately placed implants in the maxilla, and immediate placement and immediate loading protocols for the mandible were followed. The study calculated the 7-year cumulative survival rates (CSR), and a Bayesian hierarchical Cox proportional hazard model was used to measure the effect of covariates. Patient satisfaction on chewing ability, esthetic appearance, and overall satisfaction was also measured with a face-to-face interview survey. RESULTS: Of the total 370 implants, 194 were immediate placement. Two delayed loading maxillary implants failed within the first year, and another one failed in the second year of loading. Two failures were recorded in the first year and one in seven years for the immediate loading mandibular implants. The 1-, 5-, and 7-year CSR of the 370 implants were 0.989 (0.979, 1.000), 0.986 (0.975, 0.998), and 0.978 (0.957, 0.999), respectively. Only the length of the implant affected implant failure (p < 0.05); other patient characteristics, systemic diseases, implant diameter, immediate loading, and immediate placement, did not have an effect on implant failure rates. Patients reported a high degree of satisfaction regardless of their age group or length of the observation period. CONCLUSIONS: Immediately placed implant had CSR as high as delayed placed implants, and 7-year CSRs of immediate loading were not significantly different from delayed loading. The procedure also had a high degree of chewing ability, esthetic appearance, and overall satisfaction. The study results suggested that the clinical procedures applied in this study to completely edentulous patients were acceptable rehabilitation procedures.

Reduced late positive potentials to distress in individuals with high psychopathic traits during pain judgment tasks.

This study examined the empathic processing of individuals with psychopathic traits and healthy controls in response to pain, applying affective perspective-taking (Self vs. Other). Twenty subjects with high psychopathic traits and twenty control subjects performed pain judgment tasks in the study. During the tasks, late positive potentials (LPPs) of the participants were measured to assess emotional processing in reaction to visual stimuli depicting painful or non-painful situations. In early LPP time stage (500-700 ms), the control group and the psychopathic trait group exhibited comparable levels of empathic processing regarding pain. However, in late LPP time window (700-1100 ms), the control group showed a greater LPP amplitude to Pain stimuli than No-pain stimuli, whereas the psychopathic trait group exhibited non-significant amplitude differences between Pain and No-pain stimuli. These findings imply that individuals with high psychopathic traits may swiftly terminate the processing and encounter difficulties in reappraising distress cues, especially in the late stage, providing psychophysiological support for distinctive empathic processing with temporal aspects.

Ethanol extract from Astilbe chinensis inflorescence suppresses inflammation in macrophages and growth of oral pathogenic bacteria.

Chronic oral inflammation and biofilm-mediated infections drive diseases such as dental caries and periodontitis. This study investigated the anti-inflammatory and antibacterial potential of an ethanol extract from Astilbe chinensis inflorescence (GA-13-6) as a prominent candidate for natural complex substances (NCS) with therapeutic potential. In LPS-stimulated RAW 264.7 macrophages, GA-13-6 significantly suppressed proinflammatory mediators, including interleukin-6 (IL-6), tumor necrosis factor (TNF), and nitric oxide (NO), surpassing purified astilbin, a known bioactive compound found in A. chinensis. Furthermore, GA-13-6 downregulated the expression of cyclooxygenase-2 (COX2) and inducible nitric oxide synthase (iNOS), indicating an inhibitory effect on the inflammatory cascade. Remarkably, GA-13-6 exhibited selective antibacterial activity against Streptococcus mutans, Streptococcus sanguinis, and Porphyromonas gingivalis, key players in dental caries and periodontitis, respectively. These findings suggest that complex GA-13-6 holds the potential for the treatment or prevention of periodontal and dental diseases, as well as various other inflammation-related conditions, while averting the induction of antibiotic resistance.

Highly accurate measurement of the relative abundance of oral pathogenic bacteria using colony-forming unit-based qPCR.

PURPOSE: Quantitative polymerase chain reaction (qPCR) has recently been employed to measure the number of bacterial cells by quantifying their DNA fragments. However, this method can yield inaccurate bacterial cell counts because the number of DNA fragments varies among different bacterial species. To resolve this issue, we developed a novel optimized qPCR method to quantify bacterial colony-forming units (CFUs), thereby ensuring a highly accurate count of bacterial cells. METHODS: To establish a new qPCR method for quantifying 6 oral bacteria namely, Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Prevotella intermedia, Fusobacterium nucleatum, and Streptococcus mutans, the most appropriate primer-probe sets were selected based on sensitivity and specificity. To optimize the qPCR for predicting bacterial CFUs, standard curves were produced by plotting bacterial CFU against Ct values. To validate the accuracy of the predicted CFU values, a spiking study was conducted to calculate the recovery rates of the predicted CFUs to the true CFUs. To evaluate the reliability of the predicted CFU values, the consistency between the optimized qPCR method and shotgun metagenome sequencing (SMS) was assessed by comparing the relative abundance of the bacterial composition. RESULTS: For each bacterium, the selected primer-probe set amplified serial-diluted standard templates indicative of bacterial CFUs. The resultant Ct values and the corresponding bacterial CFU values were used to construct a standard curve, the linearity of which was determined by a coefficient of determination (r²) >0.99. The accuracy of the predicted CFU values was validated by recovery rates ranging from 95.1% to 106.8%. The reliability of the predicted CFUs was reflected by the consistency between the optimized qPCR and SMS, as demonstrated by a Spearman rank correlation coefficient (ρ) value of 1 for all 6 bacteria. CONCLUSIONS: The CFU-based qPCR quantification method provides highly accurate and reliable quantitation of oral pathogenic bacteria.

Frontoparietal activity during deceptive responses in the P300-based guilty knowledge test: an sLORETA study.

The cortical source activity during the P300-based guilty knowledge test (GKT) conducted using Korean sentences was investigated. Thirty male students performed a guilty or an innocent scenario, and then underwent an electroencephalogram test. The stimuli consisted of target, probe, and irrelevant stimuli that were presented visually. A target stimulus is a task-relevant stimulus that is presented rarely, attracts subjects' attention, and induces a P300 wave. A probe stimulus, also presented rarely, contains crime-relevant information that induces P300 in a guilty subject. A guilty subject would be also attentive to the probe stimulus as to the target stimulus. An irrelevant stimulus is not related to the task or to the crime, and is frequently presented. Event-related potential (ERP) data showed a marked difference between the guilty and innocent groups. Compared to irrelevant stimuli, the probe stimulus elicited larger P300 amplitude in the bilateral frontoparietal region in the guilty group. However, this pattern was not observed in the innocent group. Standardized low-resolution electromagnetic tomography (sLORETA) analysis showed significant activation increases for the probe stimulus in the guilty group. It appears that the guilty and innocent groups use different cognitive mechanisms when processing the crime-relevant sentence. With regards to the cortical activity in response to the probe stimulus, the frontal activation for verb elements seems to reflect a working memory process, episodic memory retrieval, and response inhibition, while parietal activation for complement (adverb) and object (noun) elements seems to reflect selective attention and target discrimination. To our knowledge, this is the first research to examine the cortical source of the ERP evoked by the P300-based GKT using separate Korean sentence elements.

Standard operating procedures for the collection, processing, and storage of oral biospecimens at the Korea Oral Biobank Network.

PURPOSE: The Korea Oral Biobank Network (KOBN) was established in 2021 as a branch of the Korea Biobank Network under the Korea Centers for Disease Control and Prevention to provide infrastructure for the collection, management, storage, and utilization of human bioresources from the oral cavity and associated clinical data for basic research and clinical studies. METHODS: To address the need for the unification of the biobanking process, the KOBN organized the concept review for all the processes. RESULTS: The KOBN established standard operating procedures for the collection, processing, and storage of oral samples. CONCLUSIONS: The importance of collecting high-quality bioresources to generate accurate and reproducible research results has always been emphasized. A standardized procedure is a basic prerequisite for implementing comprehensive quality management of biological resources and accurate data production.

Antimicrobial activity of Limosilactobacillus fermentum strains isolated from the human oral cavity against Streptococcus mutans.

Oral probiotics have been recently gaining much attention owing to their potential to inhibit the progression of dental caries by controlling the cariogenic effects of Streptococcus mutans. We isolated and genotypically identified 77 lactic acid bacteria including 12 Limosilactobacillus fermentum probiotic candidates from the oral cavity of healthy volunteers. Among the 12 L. fermentum isolates, nine isolates effectively inhibited the growth of S. mutans via hydrogen peroxide (H2O2) production. The others neither suppressed the growth of S. mutans nor produced H2O2. Eight out of the nine H2O2-producing L. fermentum isolates exhibited strong adherence to oral epithelial KB cells while inhibiting the adherence of S. mutans to KB cells. The eight H2O2-producing isolates were neither haemolytic based on a blood-agar test, cytotoxic according to lactate dehydrogenase assay, nor resistant to eight antibiotics represented by the European Food Safety Authority guideline, indicating that the isolates have potential to suppress the cariogenesis driven by S. mutans while providing general probiotic benefits.

Whole-Genome Sequence of Limosilactobacillus fermentum Strain DM075, Isolated from the Human Oral Cavity.

Here, we report the complete genome sequence of nitric oxide (NO)-producing Limosilactobacillus fermentum strain DM075, which was isolated from human tongue coating samples from healthy donors in South Korea. The complete genome sequence of DM075 comprises a single circular 2,204,022-bp genome, with a GC content of 51.0%, and lacks antimicrobial resistance genes.

Complete Genome Sequence of Hydrogen Peroxide-Producing Limosilactobacillus fermentum DM072 Isolated from the Human Oral Cavity.

The complete genome of hydrogen peroxide (H2O2)-producing Limosilactobacillus fermentum strain DM072, isolated from the oral cavity of healthy volunteers in South Korea, was sequenced by long-read sequencing and was subsequently corroborated by short-read sequencing. The genome comprises one circular chromosome and one plasmid and lacks antimicrobial resistance genes.

Complete Genome Sequence of Lacticaseibacillus rhamnosus DM065, Isolated from the Human Oral Cavity.

The 3.0-Mb complete genome of Lacticaseibacillus rhamnosus strain DM065, which was isolated from the oral cavity of healthy volunteers in South Korea, was sequenced using a combination of PacBio and Illumina technologies. The genome consists of one circular chromosome and two plasmids and lacks antimicrobial resistance genes.

Complete Genome Sequence of Lactiplantibacillus plantarum Strain DM083 Isolated from Human Tongue Coating.

We isolated Lactiplantibacillus plantarum DM083 from the human tongue coating to establish a strain library for oral probiotics. It has a single circular 3,197,299 bp chromosome with a guanine-cytosine (GC) content of 44.6% without plasmids. Importantly, the genome is devoid of the antimicrobial resistance gene, satisfying the minimum safety requirement for probiotics.

Lactobacillus reuteri AN417 cell-free culture supernatant as a novel antibacterial agent targeting oral pathogenic bacteria.

Lactobacillus reuteri AN417 is a newly characterized probiotic strain. The activity of AN417 against oral pathogenic bacteria is unknown. We investigated the antibacterial activity of cell-free L. reuteri AN417 culture supernatant (LRS) against three oral pathogens: Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus mutans. P. gingivalis and F. nucleatum have been implicated in periodontal disease, whereas S. mutans causes dental caries. Exposing these oral pathogenic bacteria to LRS significantly reduced their growth rates, intracellular ATP levels, cell viability, and time-to-kill. The minimal inhibitory volume of LRS was 10% (v/v) against P. gingivalis, 20% (v/v) for F. nucleatum, and 30% (v/v) for S. mutans. LRS significantly reduced the integrity of biofilms and significantly suppressed the expression of various genes involved in P. gingivalis biofilm formation. The L. reuteri AN417 genome lacked genes encoding reuterin, reuteran, and reutericyclin, which are major antibacterial compounds produced in L. reuteri strains. LRS treated with lipase and α-amylase displayed decreased antibacterial activity against oral pathogens. These data suggest that the antibacterial substances in LRS are carbohydrates and/or fatty acid metabolites. Our results demonstrate that LRS has antimicrobial activity against dental pathogenic bacteria, highlighting its potential utility for the prevention and treatment of P. gingivalis periodontal disease.

Cortical network dynamics during source memory retrieval: current density imaging with individual MRI.

We investigated the neural correlates of source memory retrieval using low-resolution electromagnetic tomography (LORETA) with 64 channels EEG and individual MRI as a realistic head model. Event-related potentials (ERPs) were recorded while 13 healthy subjects performed the source memory task for the voice of the speaker in spoken words. The source correct condition of old words elicited more positive-going potentials than the correct rejection condition of new words at 400-700 ms post-stimulus and the old/new effects also appeared in the right anterior region between 1,000 and 1,200 ms. We conducted source reconstruction at mean latencies of 311, 604, 793, and 1,100 ms and used statistical parametric mapping for the statistical analysis. The results of source analysis suggest that the activation of the right inferior parietal region may reflect retrieval of source information. The source elicited by the difference ERPs between the source correct and source incorrect conditions exhibited dynamic change of current density activation in the overall cortices with time during source memory retrieval. These results indicate that multiple neural systems may underlie the ability to recollect context.

Impairment of source memory in patients with obsessive-compulsive disorder: equivalent current dipole analysis.

We examined memory performance and cortical source localization of old/new effects in a source memory task in obsessive-compulsive disorder (OCD) patients by employing an equivalent current dipole (ECD) model using EEG and a realistic head model. Event-related potentials (ERPs) were recorded while 14 OCD patients and 14 age-, sex-, handedness-, and educational level-matched healthy control subjects performed recognition tasks for spoken words (items) or for the voice of the speaker of spoken words (sources). In the item memory task, both groups showed ERP old/new effects at 300-700 ms. In the source memory task, the controls showed ERP old/new effects at 400-700 ms, whereas the OCD patients did not. Compared with the controls, the OCD patients showed significantly lower source accuracy and prolonged reaction times to the old words with accurate voice judgments. There were no differences between the OCD and control groups with regard to the locations of the ERP generators elicited by source correct and correct rejection conditions. The OCD patients showed significantly altered hemispheric asymmetry of ECD power in the frontal lobe during source memory retrieval, compared with the controls. These results indicate that OCD patients have preserved item memory about content, but impaired source memory about context.

Neuropsychological correlates of N400 anomalies in patients with schizophrenia: A preliminary report.

We investigated N400 anomalies and their relationship with neuropsychological disturbance of schizophrenia. Twelve patients with schizophrenia and 12 normal controls, matched for age, sex, education and handedness underwent both the neuropsychological test and the electrophysiological recordings employing semantic violation sentence paradigm. The patients with schizophrenia showed a reduced N400 amplitude and worse performance in the frontal lobe function test compared to healthy participants. Furthermore, statistically significant positive correlations were found between N400 amplitude and neuropsychological performances on the Stroop Task and Wisconsin Card Sorting Test in patients with schizophrenia. Our results suggest the possibility that N400 anomalies reflect the disturbed integrity of the fronto-temporal network in schizophrenia evidenced by neuropsychological deficits. In addition, we concluded that the N400 amplitude is a candidate for an endophenotype marker of schizophrenia by revealing its relationship to neuropsychological deficits.

Association of Periodontitis with the Concentration Levels of Germanium and Tin in Hair.

The purpose of this study was to investigate whether or not the concentration levels of certain kinds of trace elements in hair are associated with periodontitis. We studied a total of 109 participants, which are composed of 25 participants with periodontitis and 84 participants without periodontitis. Periodontal conditions were assessed by measuring the periodontal clinical attachment loss and pocket depth, which were determined at six sites of all teeth. Periodontitis was defined according to the criteria of periodontitis proposed by CDC-AAP. The hair samples were washed with acetone, water, and extran (1%v/v), and then aliquots of hair samples were wet-ashed. This sample solution was analyzed by Perkin-Elmer Mass Spectrometer. The odds ratios and 95% confidence intervals of the concentration levels of trace elements for periodontitis were calculated by multivariate logistic regression analysis. After adjusting all confounders, it was found that the higher concentration level of germanium in hair was significantly and positively associated with periodontitis (odds ratio [OR] 7.12; 95% confidential interval [CI] 2.03-25.00). The higher concentration level of tin in hair was significantly and negatively associated with periodontitis (OR 0.27; 95% CI 0.08-0.94). It was concluded that there was a significant relationship between periodontitis and the concentration level of germanium and tin in hair.

Generators of the gamma-band activities in response to rare and novel stimuli during the auditory oddball paradigm.

In this study, we report the cortical sources of the gamma-band activity emitted during the auditory oddball paradigm using the adaptive beamformer algorithm and non-parametric permutation test and then compare them with those of the P3a and P3b components. The results of the gamma-band current sources revealed that the same gamma-band activities are in process during the rare target and novelty task. In the low (30-55 Hz) gamma-band activity, the common sources were localized in the (inferior) anterior cingulate and adjacent inferior frontal cortex. In the high (65-85 Hz) gamma-band activity, the generator was represented in the superior frontal cortex. On the other hand, the P3a and P3b generators showed widespread distributions including the well-known fronto-parietal network [J. Polich, Theoretical overview of P3a and P3b, in: J. Polish (Ed.), Detection of Change: Event-Related Potential and fMRI Findings, Kluwer Academic Press, Boston, 2003, pp. 83-98]. In conclusion, the same frontal generators of gamma-band activities in the present study may be associated with the functions of attentional control for the binding of consecutive cognitive stages corresponding to earlier P3a and later P3b components, which have distinct source distributions except for some overlaps.

Shape deformity of the corpus striatum in obsessive-compulsive disorder.

Volumetric changes of striatal structures based on magnetic resonance imaging (MRI) have been inconsistent in patients with obsessive-compulsive disorder (OCD) due to methodological limitations. The purpose of this study was to investigate shape deformities of the corpus striatum in patients with OCD. We performed 3-D shape deformation analysis of the caudate nucleus, the putamen, and the globus pallidus in 36 patients with OCD and 36 healthy normal subjects. Shape analysis showed deformity of the striatal structures, especially the caudate nucleus. Outward deformities in the superior, anterior portion of the bilateral caudate were observed in patients with OCD. In addition, an outward deformity in the inferior, lateral portion of the left putamen was also detected. These results suggest that patients with OCD have shape deformities of the corpus striatum, especially the caudate nucleus, compared with healthy normal subjects, and that shape analysis may provide an important complement to volumetric MRI studies in investigating the pathophysiology of OCD.

Is yogurt intake associated with periodontitis due to calcium?

The purpose of this study is to determine whether the lower intakes of yogurt, milk, and calcium are associated with periodontitis in a nationally representative sample of Korean adults. This study comprised 6,150 adults 19 or more years old who took both periodontal examination and nutrition survey. The frequency of yogurt and milk intake was examined with a food frequency questionnaire. The amount of calcium intake was calculated with dietary intakes data gained from complete one-day 24-hour recall interviews. Periodontitis was assessed using the Community Periodontal Index (CPI). Multivariate logistic regression analyses were performed for the whole sample and subgroups with the strata of age, gender, or smoking, in a complex sampling design. Less intake of yogurt was significantly associated with periodontitis (odds ratio [OR] 0.82, 95% confidential interval [CI] 0.70-0.97), but neither less intake of milk (OR 1.04, 95% CI 0.89-1.20) nor lower intake of calcium (OR 1.04, 95% CI 0.89-1.21) was significantly associated with periodontitis. In the subgroup analysis, no difference in the association of yogurt intake with periodontitis was found according to the strata of age, gender, and smoking. In conclusion, periodonitis was significantly associated with the less intake of yogurt among the Korean adults, but the calcium contained in yogurt is not likely to cause it.

Implicit and explicit memory in patients with obsessive-compulsive disorder: an event-related potential study.

The implicit and explicit memory in patients with obsessive-compulsive disorder (OCD) was investigated using the event-related potential (ERP). For the assessment of implicit memory, a lexical decision task was administered. Among a total of 320 words and 140 non-words, 200 words were repeated, while the remaining 120 words and the 140 non-words were not repeated. For explicit memory, a continuous recognition task was administered, in which 280 words were repeated and 100 were not repeated. On the recognition task, both the controls and OCD patients showed more positivity to the old words than to the new words during the 200-600 ms period post-stimulus. Both groups showed faster response time to the old words than to the new words. On the lexical decision task, the controls showed the old/new effect during the 200-500 ms period post-stimulus, while the OCD patients did not. However, OCD patient showed faster response time to the old words than to the new words, although OCD patients showed prolonged response times to the old words compared to the controls. These results indicate that OCD patients have preserved explicit and implicit memory. The absence of old/new effect on ERP in OCD patients was discussed in terms of dysfunction of frontostriatal system, which plays an important role in both OCD and implicit memory.