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PURPOSE@#. This study aims to clinically compare the fitness and trueness of zirconia crowns fabricated by different combinations of open CAD-CAM systems. @*MATERIALS AND METHODS@#. Total of 40 patients were enrolled in this study, and 9 different zirconia crowns were prepared per patient. Each crown was made through the cross-application of 3 different design software (EZIS VR, 3Shape Dental System, Exocad) with 3 different processing devices (Aegis HM, Trione Z, Motion 2). The marginal gap, absolute marginal discrepancy, internal gap(axial, line angle, occlusal) by a silicone replica technique were measured to compare the fit of the crown. The scanned inner and outer surfaces of the crowns were compared to CAD data using 3D metrology software to evaluate trueness. @*RESULTS@#. There were significant differences in the marginal gap, absolute marginal discrepancy, axial and line angle internal gap among the groups (P .05). @*CONCLUSION@#. All 9 groups showed clinically acceptable level of marginal gaps ranging from 74.26 to 112.20 μm in terms of fit comparison. In the comparison of trueness, no significant difference within each group was spotted. Within the limitation of this study, open CAD-CAM systems used in this study can be assembled properly to fabricate zirconia crown. [J Adv Prosthodont 2023;15:155-70]
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PURPOSE@#This prospective clinical study was conducted to evaluate the clinical usefulness of the freely detachable zirconia ball- and spring-retained implant prosthesis (BSRP) through a comparative analysis of screw- and cement-retained implant prosthesis (SCRP). @*MATERIALS AND METHODS@#A multi-center, randomized, prospective clinical study evaluating the clinical usefulness of the detachable zirconia ball- and spring-retained implant prostheses was conducted. Sixty-four implant prostheses in 64 patients were examined. Periodic observational studies were conducted at 0, 3, 6, and 12 months after delivery of the implant prosthesis. Factors such as implant success rate, marginal bone resorption, periodontal pocket depth, plaque and bleeding index, and prosthetic complications were evaluated, respectively. @*RESULTS@#During the 1-year observation period, all implants survived without functional problems and clinical mobility, showing a 100% implant success rate. Marginal bone resorption was significantly higher in the SCRP group than in the BSRP group only at the time of implant prosthesis delivery (P = .043). In all observation periods, periodontal pocket depth was slightly higher in the BSRP group than in the SCRP group, but there was no significant difference (P > .05). The modified plaque index (mPI) scores of both groups were moderate. Higher ratio of a score 2 in modified sulcus bleeding index (mBI) was observed in the BSRP group in the 6- and 12-months observation. @*CONCLUSION@#Within the limitations of this study, the newly developed zirconia ball- and spring-retained implant prosthesis could be considered as an applicable and predictable treatment method along with the existing screw- and cement-retained prosthesis.
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PURPOSE@#The purpose of this study was to investigate changes in retention and wear pattern of Locator® and ADD-TOC attachments on a digital milled bar by performing chewing simulation and repeated insertion/removal of prostheses in fully edentulous models. @*MATERIALS AND METHODS@#Locator (Locator®; Zest Anchors Inc., Escondido, CA, USA) was selected as the control group and ADD-TOC (ADDTOC; PNUAdd Co., Ltd., Busan, Republic of Korea) as the experimental group. A CAD-CAM milled bar was mounted on a master model and 3 threaded holes for connecting a bar attachment was formed using a tap. Locator and ADD-TOC attachments were then attached to the milled bar. Simulated mastication and repeated insertion/removal were performed over 400,000 cyclic loadings and 1,080insertions/removals, respectively. Wear patterns on deformed attachment were investigated by field emission scanning electron microscopy. @*RESULTS@#For the ADD-TOC attachments, chewing simulation and repeated insertion/removal resulted in a mean initial retentive force of 24.43 ± 4.89 N, which were significantly lower than that of the Locator attachment, 34.33 ± 8.25 N (P < .05). Amounts of retention loss relative to baseline for the Locator and ADD-TOC attachments were 21.74 ± 7.07 and 8.98 ± 5.76 N (P < .05). @*CONCLUSION@#CAD-CAM milled bar with the ADD-TOC attachment had a lower initial retentive force than the Locator attachment. However, the ADD-TOC attachment might be suitable for long-term use as it showed less deformation and had a higher retentive force after simulated mastication and insertion/removal repetitions.
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Mini-implant has been reported as an alternative method to conventional diameter implants in the treatment of mandibular anterior region with narrow ridge. However, one-piece type mini-implant showed biological and technical complications, such as peri-implantitis by residual cement and prosthetic detachment. Recently, one-piece type mini-implant with additional retentive structure has been introduced to increase the retention and stability of the mini-implant. The mini-implant is based on spreading the upper retentive structure with a spreader and connected it with the inner surface of the zirconia prosthesis. In two cases, we tried to reduce these complications through the mini-implant on the narrow mandibular anterior region, and it was possible to reduce the overall treatment period through a digital system. In this case report, restoration using the digital mini-implant system showed improvement of patient satisfaction on the aspect of function and esthetic in the narrow mandibular anterior region.
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Mushroom strains of Polyporales from the genera Coriolus, Trametes, Pycnoporus, Ganoderma, and Formitella were explored in terms of mycelial growth characteristics for the application of mushroom mycelia as alternative sources of materials replacing fossil fuel-based materials.Among the 64 strains of Polyporales, G. lucidum LBS5496GL was selected as the best candidate because it showed fast mycelial growth with high mycelial strength in both the sawdust-based solid medium and the potato dextrose liquid plate medium. Some of the Polyporales in this study have shown good mycelial growth, however, they mostly formed mycelial mat of weak physical strength. The higher physical strength of mycelial mat by G. lucidum LBS5496GL was attributed to its thick hyphae with the diameter of 13 ㎛ revealed by scanning electron microscopic analysis whereas the hyphae of others exhibited less than 2 ㎛. Glycerol and skim milk supported the best mycelial growth of LBS5496GL as a carbon and a nitrogen source, respectively.
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Mushroom strains of Polyporales from the genera Coriolus, Trametes, Pycnoporus, Ganoderma, and Formitella were explored in terms of mycelial growth characteristics for the application of mushroom mycelia as alternative sources of materials replacing fossil fuel-based materials.Among the 64 strains of Polyporales, G. lucidum LBS5496GL was selected as the best candidate because it showed fast mycelial growth with high mycelial strength in both the sawdust-based solid medium and the potato dextrose liquid plate medium. Some of the Polyporales in this study have shown good mycelial growth, however, they mostly formed mycelial mat of weak physical strength. The higher physical strength of mycelial mat by G. lucidum LBS5496GL was attributed to its thick hyphae with the diameter of 13 ㎛ revealed by scanning electron microscopic analysis whereas the hyphae of others exhibited less than 2 ㎛. Glycerol and skim milk supported the best mycelial growth of LBS5496GL as a carbon and a nitrogen source, respectively.
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Background@#and Purpose Both hypertension and hypotension increase cerebral white matter hyperintensities. However, the effects of hypotension in individuals with treated hypertension are unknown. We analyzed the association of low blood pressure with the location and amount of white matter hyperintensities between elderly individuals with controlled hypertension and those without hypertension. @*Methods@#We enrolled 505 community-dwelling, cognitively normal elderly individuals from the participants of the Korean Longitudinal Study on Cognitive Aging and Dementia. We measured blood pressure three times in a sitting position using a mercury sphygmomanometer and defined low systolic and diastolic blood pressure as ≤110 and ≤60 mm Hg, respectively. We segmented and quantified the periventricular and deep white matter hyperintensities from 3.0 Tesla fluid-attenuated inversion recovery magnetic resonance images. @*Results@#Low systolic blood pressure was independently associated with larger volume of periventricular white matter hyperintensity (P=0.049). The interaction between low systolic blood pressure and hypertension was observed on the volume of periventricular white matter hyperintensity (P=0.005). Low systolic blood pressure was associated with the volume of periventricular white matter hyperintensity in individuals with controlled hypertension (F1,248=6.750, P=0.010), but not in those without hypertension (P=0.380). Low diastolic blood pressure was not associated with the volumes of white matter hyperintensities regardless of presence of controlled hypertension. @*Conclusions@#Low systolic blood pressure seems to be associated with larger volume of periventricular white matter hyperintensity in the individuals with a historyof hypertension but not in those without hypertension.
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Objective@#Cardiovascular diseases are representative risk factors for the onset of cognitive decline. The purpose of this study was to confirm the relationship between diastolic blood pressure and cognitive function in elderly people in Korea. @*Methods@#Data from subjects who were enrolled in the prospective Korean Longitudinal Study on Cognitive Aging and Dementia were used in this study. Data from 701 subjects whose diastolic blood pressure range did not change (≤79 mm Hg or ≥80 mm Hg) over 2 years were analyzed. To analyze the differences in cognitive function between the groups at the 2-year follow-up, an analysis of covariance was performed with covariates, which were significantly different between the two groups, and the baseline cognitive function. @*Results@#Significant differences were observed between the two groups, and the mean scores on the constructional praxis (η2=0.010) and word list recall tests (η2=0.018) in the diastolic blood pressure ≥80 mm Hg group were higher than those in the diastolic blood pressure ≤79 mm Hg group at the 2-year follow-up. @*Conclusion@#These results indicate that maintaining a DBP below 79 mm Hg presents a greater risk of cognitive decline in Korean elderly people.
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Objective@#This study estimated the incidence of driving-related adverse events and examined the association of cognitive function with the risk of future driving-related adverse events in the elderly Korean male population. @*Methods@#We analyzed 1,172 male drivers aged 60 years or older in the Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD). Using the data from Korean National Police Agency, we classified the participants into three groups: safe driving (drove for 2 years after baseline without a traffic accident or repeated violations), driving cessation (stopped driving), and risky driving (one or more traffic accidents or repeated violations). We estimated the incidences of driving cessation and risky driving, and examined the effect of cognitive function on their risks. @*Results@#The incidence of driving cessation and risky driving in the Korean male drivers aged 60 years or older was 19.3 and 69.9 per 1,000 person-years respectively and increased in the late 80s. Drivers with better baseline Word List Memory Test scores showed less risky driving (OR=0.94, p=0.039). @*Conclusion@#Driving-related adverse events increased in late 80s, and better memory function was protective against these events.
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PURPOSE: The purpose of this study was to compare the clinical outcomes of lithium disilicate ceramic pressed zirconia prostheses and monolithic zirconia prostheses and to investigate the complications after two years of follow-up in posterior edentulous site. MATERIALS AND METHODS: A total 17 patients (male: 12, female: 5) were treated with 60 posterior fixed implant-supported prostheses (LP. lithium disilicate ceramic pressed zirconia prostheses: n = 30, MZ. monolithic zirconia prostheses: n = 30). After 24-month, clinical examination of Implant survival rate, marginal bone resorption, probing depth, plaque index, bleeding index, calculus and complications were evaluated. RESULTS: There were no failed implants and all implants were normal in function without mobility. Marginal bone resorption was lower in LP group than MZ group at 12-month (P < .05), and 12-month probing depth and calculus deposit in LP group were significantly higher than MZ group (P < .05). Most common complications in MZ were marginal bone resorptions more than 1.5.mm and 2 chipping occurred in LP group. CONCLUSION: Within the limitations of the present study, lithium disilicate ceramic pressed zirconia is considered as a predictable treatment option as much as monolithic zirconia in posterior fixed implant-supported prostheses.
Subject(s)
Female , Humans , Bone Resorption , Calculi , Ceramics , Dental Implants , Follow-Up Studies , Hemorrhage , Lithium , Prospective Studies , Prostheses and Implants , Survival RateABSTRACT
This case study was to report the possible increase in the denture retention and psychological relief using the implant-supported fixed prostheses in a completely edentulous patient. The implants were placed in the anterior portion of the mandible in a patient who had completely edentulous state following the extraction of residual abutment teeth, and consequently a distal extension removable partial denture was fabricated. The patient's adaptation and satisfaction to the new prosthesis was monitored and confirmed in terms of masticatory function and esthetics, by restoring the oral condition similar to initial status before the residual teeth extraction. After 6 months, radiographic examination confirmed that both the abutment teeth and the implants were stable and well maintained. Considering the relatively short clinical follow-up period, however, continuous long-term monitoring was required.
Subject(s)
Humans , Dental Prosthesis, Implant-Supported , Denture Retention , Denture, Partial, Removable , Esthetics , Follow-Up Studies , Mandible , Mandibular Prosthesis , Prostheses and Implants , ToothABSTRACT
PURPOSE: This study evaluated the accuracies of different bite registration techniques for implant-fixed prostheses using three dimensional file analysis. MATERIALS AND METHODS: Implant fixtures were placed on the mandibular right second premolar, and the first and second molar in a polyurethane model. Aluwax (A), Pattern Resin (P), and Blu-Mousse (B) were used as the bite registration materials on the healing abutments (H) or temporary abutments (T). The groups were classified into HA, HP, HB, TA, TP, and TB according to each combination. The group using the bite impression coping was the BC group; impression taking and bite registration were performed simultaneously. After impression and bite taking, the scan bodies were connected to the lab analogs of the casts. These casts were scanned using a model scanner. The distances between two reference points in three-dimensional files were measured in each group. One-way ANOVA and Duncan's test were used at the 5% significance level. RESULTS: The smallest distance discrepancy was observed in the TB group using the temporary abutments. The Blu-Mousse and HP groups showed the largest distance discrepancy. The TB and BC groups showed a lower distance discrepancy than the HP group (P=.001), and there was no significant difference between the groups using the temporary abutments and healing abutments (P>.05). CONCLUSION: Although this study has limitations as an in-vitro investigation, the groups using the temporary abutments to hold the Blu-Mousse record and bite impression coping showed greater accuracy than the group using the healing abutments to hold the pattern resin record.
Subject(s)
Bicuspid , Jaw Relation Record , Molar , Pilot Projects , Polyurethanes , Prostheses and ImplantsABSTRACT
PURPOSE: The purpose of this study was to determine fracture resistance and failure modes of three-unit fixed dental prostheses (FDPs) made of lithium disilicate pressed on zirconia (LZ), monolithic lithium disilicate (ML), and monolithic zirconia (MZ). MATERIALS AND METHODS: Co-Cr alloy three-unit metal FDPs model with maxillary first premolar and first molar abutments was fabricated. Three different FDPs groups, LZ, ML, and MZ, were prepared (n = 5 per group). The three-unit FDPs designs were identical for all specimens and cemented with resin cement on the prepared metal model. The region of pontic in FDPs was given 50,000 times of cyclic preloading at 2 Hz via dental chewing simulator and received a static load until fracture with universal testing machine fixed at 10°. The fracture resistance and mode of failure were recorded. Statistical analyses were performed using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni's correction (α=0.05/3=0.017). RESULTS: A significant difference in fracture resistance was found between LZ (4943.87 ± 1243.70 N) and ML (2872.61 ± 658.78 N) groups, as well as between ML and MZ (4948.02 ± 974.51 N) groups (P.05). With regard to fracture pattern, there were three cases of veneer chipping and two interfacial fractures in LZ group, and complete fracture was observed in all the specimens of ML and MZ groups. CONCLUSION: Compared to monolithic lithium disilicate FDPs, monolithic zirconia FDPs and lithium disilicate glass ceramics pressed on zirconia-based FDPs showed superior fracture resistance while they manifested comparable fracture resistances.
Subject(s)
Alloys , Bicuspid , Ceramics , Dental Prosthesis , Denture, Partial, Fixed , Glass , In Vitro Techniques , Lithium , Mastication , Molar , Resin CementsABSTRACT
The purpose of this study was to compare the changes of retentive force in different stud attachment systems for implant retained overdenture. Two commercially available attachments with different retentive forces were investigated: Kerator (pink, blue, red) and O-ring (orange, red). Two implant fixtures were vertically embedded in base mountings. Five pairs of each attachment were evaluated. A universal testing machine was used to evaluate the retentive force of two attachments during wear simulation. Surface characteristics of each attachment system were evaluated with scanning electron microscopy. Five pairs of each attachment were evaluated. Kerator pink showed the highest initial retention. After 2,500 cycles of wear-simulation, Kerator pink noted the largest decrease in retention. According to results of surface analysis, Worn surfaces were obtained in matrices and patrices. Heavy wears were observed in matrices. After 2 year-wear simulation, most attachments exhibited retention loss. Attachments using different kind of material exhibited dissimilar surface alterations.
Subject(s)
Denture, Overlay , Microscopy, Electron, ScanningABSTRACT
PURPOSE: The aim of this study was to evaluate the clinical findings and patient satisfaction on implant overdenture designed with Locator implant attachment or Locator bar attachment in mandibular edentulous patients. MATERIALS AND METHODS: Implant survival rate, marginal bone loss, probing depth, peri-implant inflammation, bleeding, plaque, calculus, complications, and satisfaction were evaluated on sixteen patients who were treated with mandibular overdenture and have used it for at least 1 year (Locator implant attachment: n=8, Locator bar attachment: n=8). RESULTS: Marginal bone loss, probing depth, plaque index of the Locator bar attachment group were significantly lower than the Locator implant attachment group (P.05). The replacement of the attachment components was the most common complication in both groups. Although there was no correlation between marginal bone loss and plaque index, a significant correlation was found between marginal bone loss and probing depth. CONCLUSION: The Locator bar attachment group indicates lesser marginal bone loss and need for maintenance, as compared with the Locator implant attachment group. This may be due to the splinting effect among implants rather than the types of Locator attachment.
Subject(s)
Humans , Calculi , Denture, Overlay , Dentures , Hemorrhage , Inflammation , Patient Satisfaction , Splints , Survival RateABSTRACT
OBJECTIVES: Medical complications are common and often serious in patients with eating disorders, however, little is known about complications in patients with bulimia nervosa. METHODS: We conducted a retrospectively investigation of clinical characteristics and hematologic, biochemical, hormonal, and bone density evaluations in 90 Korean women with bulimia nervosa together with 100 healthy Korean women of comparable ages. RESULTS: In patients with bulimia nervosa, 20% were anemic, 3.3% were hypokalemic, 14.4% had increased alanine aminotransferase, 24.4% were lower in serum protein, 8.8% were hypercholesterolemia, and 77.8% were hyperamylasemia. Osteopenia at any one site was identified in 26.7% of patients and the lowest-ever body mass index was the main determinant of bone mineral density in patients with bulimia nervosa. CONCLUSION: In this study, many features of medical findings reported in anorexia nervosa were found in bulimia nervosa, however, the findings in bulimia nervosa were milder form than in anorexia nervosa. Management of any physical abnormalities in bulimia nervosa should focus on correction of the eating disorder.
Subject(s)
Female , Humans , Alanine Transaminase , Anorexia Nervosa , Body Mass Index , Bone Density , Bone Diseases, Metabolic , Bulimia Nervosa , Bulimia , Feeding and Eating Disorders , Hyperamylasemia , Hypercholesterolemia , Retrospective StudiesABSTRACT
OBJECTIVES: QT interval prolongation and dispersion known as indicators of an increased risk for ventricular arrhythmias and sudden death have been reported to be prolonged in patients with anorexia nervosa. The aims of this study were to compare conduction abnormalities in Korean patients with anorexia nervosa and bulimia nervosa, and to examine its relation with clinical and laboratory factors. METHODS: We retrospectively examined 45 women with anorexia nervosa and 75 women with bulimia nervosa who were assessed by 12-lead electrocardiogram at baseline. QT interval and corrected QT interval, QT dispersion of the difference between the longest and shortest QT intervals, and abnormal U wave were measured for conduction abnormalities. RESULTS: QT interval was significantly longer in patients with anorexia nervosa compared with those with bulimia nervosa. There were no differences in QTc (Corrected QT), QTd (QT dispersion) and abnormal U wave between patients with anorexia nervosa and those with bulimia nervosa. QTd was significantly correlated with the lowest ever lifetime body mass index (kg/m2) as well as the serum amylase level in patients with anorexia nervosa. CONCLUSIONS: These results suggest some conduction abnormalities reported in patients with anorexia nervosa are also found in patients with bulimia nervosa. It appears that severity of weight loss and purging behavior could affect the cardiac arrhythmia in patients with eating disorders. Appropriate attention should be paid to cardiac involvement in patients with eating disorders.
Subject(s)
Female , Humans , Amylases , Anorexia , Anorexia Nervosa , Arrhythmias, Cardiac , Body Mass Index , Bulimia Nervosa , Death, Sudden , Eating , Feeding and Eating Disorders , Electrocardiography , Retrospective Studies , Weight LossABSTRACT
Even though suicide ranks as the fourth cause of death and is causing a significant loss in Korea, it seems that the conventional notion regarding suicide as a feasible way of solving a troublesome life situation hinders early recognition and proper management of suicide. This article reviews suicide prevention strategies recommended based on robust experience and scientific understanding of the characteristics of the suicide problem. In the UK, a suicide prevention strategy was formed at the national level suggesting significant goals to reduce the rate of suicide. In the US, the Institute of Medicine study committee examined the state of the science base, gaps in knowledge, strategies for prevention, and research designs for the study of suicide. This recommendation includes more science-based, coherent and well-coordinated multidisciplinary approaches, and thus suggests important practical recommendations for a suicide prevention strategy of Korea. The author concludes that suicide should be defined as a treatable and even preventable medical condition. Constructing a national network of suicide research, data surveillance, developing tools for suicide prevention including early detection and safety planning, and comprehensive insurance coverage are recommended.
Subject(s)
Cause of Death , Depression , Insurance Coverage , Korea , Research Design , SuicideABSTRACT
BACKGROUND: Severity of aspiration pneumonitis is associated with acidity and volume of aspirated gastric contents. Volume and acidity of gastric contents are influenced by food, drugs, and patient factors. However, most studies were performed without controlling these factors. The objectives of this study were to determine the effects of a 20 mg intravenous famotidine injection on gastric content volume and acidity, 1 to 2 hours prior to general anesthesia after controlling the last intake of food. METHODS: One hundred twenty three healthy patients were randomly assigned to famotidine and control groups. All patients were requested to drink 200 ml of milk the night before surgery in order to control food related factors and fasting time. After induction of general anesthesia, volume and acidity of aspirated gastric contents were measured. RESULTS: There were no significant differences in acidity of aspirated gastric contents between the two groups. However, the famotidine group showed a significant aspirated gastric volume reduction compared with that of the control group. CONCLUSIONS: Famotidine premedication by intravenous injection 1 to 2 hours prior to general anesthesia may be effective to prevent aspiration pneumonitis by reducing gastric content volume.