Research trends and hotspots of post-stroke dysphagia rehabilitation: a bibliometric study and visualization analysis.

Background: Post-stroke dysphagia (PSD) is one of the most prevalent stroke sequelae, affecting stroke patients' prognosis, rehabilitation results, and quality of life while posing a significant cost burden. Although studies have been undertaken to characterize the pathophysiology, epidemiology, and risk factors of post-stroke dysphagia, there is still a paucity of research trends and hotspots on this subject. The purpose of this study was to create a visual knowledge map based on bibliometric analysis that identifies research hotspots and predicts future research trends. Methods: We searched the Web of Science Core Collection for material on PSD rehabilitation research from its inception until July 27, 2023. We used CiteSpace, VOSviewer, and Bibliometrix R software packages to evaluate the annual number of publications, nations, institutions, journals, authors, references, and keywords to describe present research hotspots and prospective research orientations. Results: This analysis comprised 1,097 articles from 3,706 institutions, 374 journals, and 239 countries or regions. The United States had the most publications (215 articles), and it is the most influential country on the subject. "Dysphagia" was the most published journal (100 articles) and the most referenced journal (4,606 citations). Highly cited references focused on the pathophysiology and neuroplasticity mechanisms of PSD, therapeutic modalities, rehabilitation tactics, and complications prevention. There was a strong correlation between the terms "validity" and "noninvasive," which were the strongest terms in PSD rehabilitation research. The most significant words in PSD rehabilitation research were "validity" and "noninvasive brain stimulation," which are considered two of the most relevant hotspots in the field. Conclusion: We reviewed the research in the field of PSD rehabilitation using bibliometrics to identify research hotspots and cutting-edge trends in the field, primarily including the pathogenesis and neurological plasticity mechanisms of PSD, complications, swallowing screening and assessment methods, and swallowing rehabilitation modalities, and this paper can provide in the follow-up research in the field of PSD rehabilitation. The results of this study can provide insightful data for subsequent studies in the field of PSD rehabilitation.

Research hotspots and frontiers of post-stroke aphasia rehabilitation: a bibliometric study and visualization analysis.

Background: Aphasia is a common complication of stroke and is associated with high morbidity and mortality rates. Rehabilitation plays a crucial role in the comprehensive management of post-stroke aphasia and its consequences. However, bibliometric analysis in the field of post-stroke aphasia rehabilitation is still lacking. This study aimed to comprehensively identify assistance networks, analyze research trends, focus on hot and cutting-edge health topics related to post-stroke aphasia rehabilitation, and inform future research guidelines. Methods: The Web of Science Core Collection (WoSCC) electronic database was searched from inception to January 4, 2023 to identify studies related to post-stroke aphasia rehabilitation. Bibliometric analysis and visualization of country, institution, journal, author, reference, and keywords were performed using CiteSpace and VOSviewer software. Results: A total of 2,325 papers were included in the analysis, with a progressive increase in the number of articles published each year. The USA was the country with the most publications (809 articles), and the University of Queensland was the institution with the most publications (137 articles). The subject area of post-stroke aphasia rehabilitation is dominated by clinical neurology (882 articles). Aphasiology was the journal with the most publications (254 articles) and the most cited journal (6,893 citations). Worrall L was the most prolific author (51 publications), and Frideriksson J was the most cited author (804 citations). Conclusion: By using bibliometrics, we provided a comprehensive review of studies related to post-stroke aphasia rehabilitation. Future research hotspots on topics related to post-stroke aphasia rehabilitation will mainly focus on the plasticity mechanisms of neurolinguistics networks, language function assessment, language rehabilitation modalities, and patients' rehabilitation needs and participation experiences in post-stroke aphasia. This paper provides systematic information that is worth exploring in the future.

Effects of nurse-led hierarchical management care on acute stroke patients: A pilot study to promote stroke-associated pneumonia management.

Background: Stroke-related pneumonia (SAP) is a common complication in acute ischemic stroke (AIS) patients, and it has adverse effects on the clinical outcomes and increases the burden on patients' families and society. Early identification and individualized care are necessary to reduce the incidence of SAP. Objective: The present study aimed to explore the effect of nurse-led hierarchical management care based on the acute ischemic stroke-associated pneumonia score (AIS-APS) scale in AIS patients. Methods: A quasi-intervention pilot study design was adopted for the present study. A total of 120 AIS patients were enrolled and assigned to the intervention group and the control group, with 60 subjects in each group in a tertiary hospital in Guangzhou, China. The control group received routine care, whereas the intervention group was given nurse-led hierarchical management care based on the AIS-APS scale. The intervention duration was more than 7 days, and the incidence of SAP, neurological function, swallowing function, and activities of daily living (ADLs) at discharge were observed. The outcomes were assessed at baseline and at outpatient time. Results: A total of 120 participants were enrolled in our study. A significant decrease was found in the incidence of SAP in the intervention group (18.3%) compared with that in the control group (41.7%). Positive outcomes were shown in neurology function, swallowing function, and ADL in the intervention group. Conclusion: Nurse-led hierarchical management care based on AIS-APS can reduce the incidence of SAP, promote AIS patients' neurological function, and maintain patients' ADL. The results of our study indicated that nurse-led hierarchical management care is feasible for AIS patients and provides individualized interventions for patients with different levels of SAP risk. Nurse-led hierarchical management care could be incorporated into routine nursing practice. Further study is needed and expected to solve more clinical problems.

Correlates of stigma for poststroke patients: A meta-analysis.

AIMS: A meta-analysis was carried out to review and identify correlates of stigma in poststroke patients. BACKGROUND: Patients suffer from impaired physical functions and sequelae of stroke. Stroke-related stigma hinders the recovery process and produces poorer clinical outcomes of stroke, leading to compromised quality of life. DESIGN: A systematic review and meta-analysis was reported by following PRISMA 2020 guidelines. REVIEW METHODS: Nine databases were searched from their inception to May 2021 to identify studies focused on the relationships among demographics, disease-related factors, psychosocial factors and poststroke stigma. Included studies were assessed by using the Agency for Healthcare Research and Quality (AHRQ) scale. The statistical software R studios were used to perform statistical analysis. RESULTS: Nineteen studies were included in the meta-analysis. Four demographic factors (age, caregiver, residence, monthly income), seven stroke-related characteristics (type of stroke, mRS, ADLs, stroke duration, recurrence, sequelae, chronic disease comorbidity) and three psychosocial factors (depression, social support, quality of life) showed significant associations with stroke-related stigma. CONCLUSIONS: The results of our study can serve as a foundation for designing interventions to reduce stigma and improve the overall quality of life of poststroke patients and may produce positive clinical outcomes. Healthcare professionals should be aware of stroke patients who are characterised by correlates of stigma. Relevance to clinical practice Poststroke patients showed a moderate-to-high level of stigma, and this issue warrants more attention. This review provides a preliminary foundation for healthcare professionals to develop interventions to address stroke-related stigma by focusing on demographic, disease-related and psychosocial factors. Additionally, stigma identification should be a part of clinical nursing evaluation. The involvement of clinical and community nursing is very important to screen stroke-related stigma and pay attention to this population.

Accuracy and efficiency of digitally fabricated all-ceramic crowns from conventional impressions and intraoral scans: A single-blind clinical randomized controlled trial.

PURPOSE: To evaluate the accuracy of intraoral scanners by comparing the marginal fit of 70 all-ceramic crowns fabricated from both conventional impressions and intraoral scans. MATERIALS AND METHODS: A total of 70 posterior teeth requiring single-crown restorations randomly underwent either intraoral scanning or conventional impression-taking followed by laboratory scanning of the casts in a parallel-group RCT. Subsequently, 70 monolithic all-ceramic crowns were CAD/CAM fabricated; only the impression technique differed. Marginal fit, internal fit, adjustment time required for insertion and occlusal contacts, and visual analog scale (VAS) scores assessing dentists' satisfaction with all of the crowns were clinically evaluated by a blinded and calibrated examiner. Data were analyzed using independent-samples t test and likelihood ratio test or Fisher exact test. All tests were performed with α = .05. RESULTS: The mean marginal fit with intraoral scanning (57.94 ± 22.51 µm) was better than with diagnostic cast scanning (82.98 ± 21.72 µm). The difference was statistically significant (P = .000). The differences in internal fit, adjustment time for crown insertion and occlusal contacts, and VAS scores were also significant, and the secondary outcomes were in favor of intraoral scanning. CONCLUSION: Within the limitations of this clinical trial, CAD/CAM-fabricated single-tooth restorations in the posterior region produced by an intraoral scanning technique using TRIOS was found to be a more accurate and efficient alternative to restorations based on conventional impressions in combination with the laboratory scanning technique.

Experiences and perceptions of stroke patients living with dysphagia: A qualitative meta-synthesis.

AIMS: To systematically review and synthesise the findings of qualitative research exploring experiences of dysphagia from stroke patients' perspectives. BACKGROUND: Poststroke patients with dysphagia are suffering from impaired physical functions and heavy psychological burden, and they are living with compromised quality of life. Through synthesising qualitative studies to fully portrait the experiences of poststroke patients living with dysphagia, we can care better for this population. DESIGN: A systematic review and synthesis of qualitative studies reported by following ENTREQ. REVIEW METHODS: Five electronic databases (CINAHL, Embase, PubMed, Web of Science and Cochrane Library) and three Chinese databases (CNKI, VIP and Wanfang) were searched from inception until January 2021. Qualitative studies were included if they were related to the experiences of poststroke patients with dysphagia. The Joanna Briggs Institute Qualitative Assessment and Review Instrument (JBI-QARI) was used to appraise study quality. Data were synthesised using the Thomas and Harden method thematic and content analysis. RESULTS: Five studies were included in the meta-synthesis. Four analytical themes were identified: life changes after dysphagia, coping with social events, rebuilding a normal life and limited professional services. CONCLUSIONS: More attention should be given to psychological health and social interaction in poststroke dysphagia patients. Healthcare professionals, especially nurses, should make joint efforts to provide patients with dysphagia-related knowledge and long-term individualised support. To improve the quality of life of dysphagia patients, further research should implement high-quality interventions based on dysphagia experience and clinical treatment. RELEVANCE TO CLINICAL PRACTICE: These findings outline the changes in poststroke patients with dysphagia. Nurses as the first-line force, should deliver comprehensive and individualised intervention for managing physiological and psychosocial symptoms of patients.

The Underrated Salivary Virome of Men Who Have Sex With Men Infected With HIV.

Salivary virome is important for oral ecosystem, but there are few reports on people living with HIV. We performed metagenomic sequencing to compare composition and functional genes of salivary virobiota between one HIV-negative and four HIV-positive groups in which participants were all men who have sex with men (MSM) with different immunosuppression statuses (five samples per group) to find the evidence that salivary virobiota plays a role in the pathogenesis of oral disease. Acute-stage subjects achieved a positive result of HIV RNA, but HIV antibody negative or indeterminate, whereas individuals with mild, moderate, and severe immunosuppression exhibited CD4+ T-lymphocyte counts of at least 500, 200-499, and less than 200 cells/µL or opportunistic infection, respectively. The results showed the composition of salivary virus genera in subjects with mild immunosuppression was the most similar to that in healthy people, followed by that in the acute stage; under severe immunosuppression, virus genera were suppressed and more similar to that under moderate immunosuppression. Furthermore, abnormally high abundance of Lymphocryptovirus was particularly obvious in MSM with HIV infection. Analysis of KEGG Pathway revealed that Caulobacter cell cycle, which affects cell duplication, became shorter in HIV-positive subjects. It is worth noting that in acute-stage participants, protein digestion and absorption related to the anti-HIV-1 activity of secretory leukocyte protease inhibitor was increased. Moreover, in the severely immunosuppressed subjects, glutathione metabolism, which is associated with the activation of lymphocytes, was enhanced. Nevertheless, the ecological dysbiosis in HIV-positive salivary virobiota possibly depended on the changes in blood viral load, and salivary dysfunction of MSM infected with HIV may be related to CD4 counts. Ribonucleoside diphosphate reductase subunit M1 in purine metabolism was negatively correlated, though weakly, to CD4 counts, which may be related to the promotion of HIV-1 DNA synthesis in peripheral blood lymphocytes. 7-Cyano-7-deazaguanine synthase in folate biosynthesis was weakly positively correlated with HIV viral load, suggesting that this compound was produced excessively to correct oral dysfunction for maintaining normal cell development. Despite the limited number of samples, the present study provided insight into the potential role of salivary virome in the oral function of HIV infected MSM.

Nomogram for Predicting Overall Survival in Acral Lentiginous Melanoma: A Population-based Study.

BACKGROUND: The objective of this study was to establish a nomogram for predicting the overall survival (OS) of patients with acral lentiginous melanoma (ALM). MATERIALS AND METHODS: The study sample was selected from 1785 patients diagnosed with ALM from 2004 to 2015 in the Surveillance, Epidemiology, and End Results (SEER) database, and R software was used to divide patients into the training cohort and validation cohort at a ratio of 7: 3. Stepwise selection method in the Cox regression model was used in the training cohort to select predictive variables to construct the nomogram, and model validation parameters were used in the validation cohort to evaluate the performance of the nomogram. RESULTS: The nomogram showed that age at diagnosis had the greatest impact on OS in patients with ALM, followed by AJCC stage, surgical treatment, SEER stage, sex, race, and marital status. The index of concordance, area under the receiver operating characteristic curve, calibration plots, net reclassification improvement, integrated discrimination improvement, and decision curve analysis demonstrate the good performance of this nomogram. CONCLUSION: The prognostic value of the nomogram is superior to that of the AJCC staging system alone, and it helps clinicians to better predict 3-, 5-, and 8-year OS in patients with ALM.

Effects of traditional Chinese exercise on patients with cognitive impairment: A systematic review and Bayesian network meta-analysis.

OBJECTIVE: To systematically review the effectiveness of four types of traditional Chinese exercise (TCE) on patients with cognitive impairment (CI) and to rank these four TCE types. DESIGN: A Bayesian network meta-analysis. METHODS: Four English databases, including PubMed, EMBASE, Cochrane Library and Web of Science, and three Chinese databases, including CNKI, VIP and Wanfang, were searched from their inception to December 2019. Randomized control trials conducted to verify the effects of TCE on patients with CI were included. We used network meta-analysis to evaluate the relative effects and rank probabilities of the four types of TCE. RESULTS: The results of the network meta-analysis indicated that baduanjin (N = 9), tai chi (N = 11), liuzijue (N = 2) and qigong (N = 1) all had significant benefits compared with control conditions. According to the ranking probabilities, baduanjin was most likely to be associated with substantial improvement in cognition, followed by tai chi, liuzijue and qigong. CONCLUSION: Our study revealed the effectiveness of TCE for improving global cognition in adults with cognitive impairment. Baduanjin may be the most effective exercise type. The evidence summarized in our study still contains bias, and more research should be carried out to verify the validity of TCE.

In Situ Synthesized Particulates on a Zirconia Ceramic Surface and Their Effect on Bonding to Porcelain.

PURPOSE: To explore the effect of in situ synthesized particulates on a zirconia surface on the bonding properties between zirconia and porcelain. MATERIALS AND METHODS: Presintered yttrium-stabilized tetragonal zirconia (Y-TZP) was cut into slices and bars and polished with 1,200-grit silicon carbide abrasive paper. Samples were randomly divided into six groups (C, I1, I3, I5, I7, and I9) according to immersion time in hydrofluoric acid solution (0, 10, 30, 50, 70, and 90 seconds, respectively). Then, the samples were placed in calcium chloride solution for 90 seconds and dipped in sodium hydroxide solution at 80°C for 2 hours. After sintering, the surface topography and roughness were examined. After the porcelain was fired, the bonding interface was observed, and cross-sectional microhardness was measured. The shear bond strength of the zirconia to porcelain was evaluated, and failure modes were classified. A 3-point bending test was applied to confirm the effects of the treatment on the mechanical properties. The above data were statistically analyzed. RESULTS: Polycrystalline particulates were synthesized on the zirconia surface. The surface roughness values increased as the immersion time of the samples in hydrofluoric acid increased. The cross-sectional microhardness decreased gradually in the experimental groups. Group I7 showed an elevated bond strength (27.02 ± 2.44 MPa). Mainly mixed failure mode was obtained in the experimental groups. The Weibull characteristic strength for the experimental groups was higher than that of group C. The flexural strengths were not significantly different among the groups. CONCLUSIONS: In situ synthesized polycrystalline particulates on zirconia could effectively improve the bonding between zirconia ceramics and porcelain without significantly decreasing the mechanical properties.

A Retrospective Study of Kidney Stone Recurrence in Adults.

BACKGROUND: Nephrolithiasis or kidney stone disease (KSD) is a common disorder worldwide. Despite the availability of a variety of effective management strategies, KSD recurrence remains a problem. In the present study, we investigated the KSD recurrence after the treatment of the first stone episode. METHODS: Medical records of all patients who had KDS treated in our department from January 2012 to January 2016 were retrospectively reviewed. A total of 146 patients who had KDS recurrence were identified. The demographic information, biochemical data, treatment methods, report of hydronephrosis severity and stone chemical compositions were collected and analyzed. RESULTS: We reported that: 1) Sixty four (43.8%) out of 146 patients with stone recurrence were overweight or obese; 2) Of all 146 patients with stone recurrence, 86 (58.9%) had hyperlipidemia, 77 (52.4%) had hyperuricemia and 64 (43.8%) had hyperglycemia; 3) Mini-invasive methods were mostly used for the treatment of the first stone episode; 4) The most chief complaint differed during the first episode and recurrence; 5) The number of patients who had grades 3 and 4 hydronephrosis was significantly lower during recurrence compared with that in the first stone episode; 6) Seventy nine (54.1%) patients with recurrence had stone of calcium oxalate. CONCLUSIONS: Majority of patients with KSD recurrence have overweight/obesity, hyperlipidemia, hyperuricemia and hyperglycemia, indicating a role of metabolic disorders in stone recurrence. Mini-invasive methods are the mainstay for the management of the first stone episode. The degree of hydronephrosis is significantly reduced during stone recurrence, possibly due to increased awareness of the disease and thereafter the change of lifestyle in patients. Over half of recurrent stones are of calcium oxalate.

Unusual Features of Clear Cell Adenocarcinoma of the Female Urethra: A Case Report and Literature Review.

BACKGROUND: There has been scarce information about clear cell adenocarcinoma of the urethra (CCAU), an extremely rare type of cancer. A few case reports show that CCAU tends to have similar clinical manifestation to the other urethral carcinomas, urethrocystoscopy can easily identify tumoral lesions in the urethra, and bloody drainage from the urethral meatus is often seen during physical exams. METHODS: A 52-year-old woman presented with dysuria for 6 months. Urethrocystoscopy did not reveal abnormality, and there was no bloody vaginal drainage or bloody drainage from the urethral meatus during physical exams. Ultrasonography demonstrated a solid mass with well-defined margins located between the anterior vaginal wall and the posterior urethral wall. Computed tomography showed the mass with smooth margins at the level of vaginal fornix, and magnetic resonance imaging showed the same location of the tumor as ultrasonography. RESULTS: Surgical removal of the tumor was successfully performed and histological and immunohistochemical analysis confirmed the final diagnosis of CCAU. CONCLUSION: Abnormality in urethrocystoscopy and bloody drainage during the physical exam were not found in this case, which is in contrast to the findings reported in literature. These unusual features add new knowledge about CCAU that deserves dissemination for improved CCAU diagnosis and management.

Competency model for dentists in China: Results of a Delphi study.

OBJECTIVE: With the increasing awareness of the importance of oral health, patients have an increasing need for integrated care from dentists. In China, the dentistry examination consists of two parts: a practical skills examination and a comprehensive medical examination; to date, no assessment methods that are based on specialized dentistry competencies, unlike the United States, Canada, and other countries, have been established. Therefore, the purpose of this study was to construct a competency model for dentists in China in order to guide the development, admission, training and assessment of dentists. METHODS: Using a literature review, focus group interviews and in-depth personal interviews, a dentist competency index was developed with an expert consultation questionnaire. A panel of 20 specialist experts was chosen from ten national medical universities to carry out two rounds of Delphi expert analysis, using the boundary value method to filter the indicators and the Analytic Hierarchy Process to calculate the weights of the primary indicators. RESULTS: Two rounds of Delphi results showed that the expert authority, enthusiasm, and coordination coefficients were high. Constructs of the competency model that included seven primary indicators and 62 secondary indicators determined the weight of each index. The seven primary indicators included the following: clinical skills and medical services, disease prevention and health promotion, interpersonal communication skills, core values and professionalism, medical knowledge and lifelong learning ability, teamwork ability and scientific research ability. CONCLUSION: In conclusion, the use of the Delphi method to construct an initial model of Chinese physician competency is scientific and feasible. The initial competency model conforms to the characteristics and quality requirements of dentists in China and has a strong scientific basis. The dentist competency model should be used in the National Dental Licensing Examination in China.

Improvement of Total Etching Dentin Bonding with Subpressure.

This study aimed to investigate the effects of subpressure on the bond properties of total-etching adhesive to dentin. Thirty-six caries-free premolars were sectioned parallel to the occlusal plane and randomly divided into four groups (n = 9): a control group (C, no treatment) and three subpressure groups, which were treated under 0.8, 0.6 or 0.4 bar after applying adhesives, named S8, S6 and S4, respectively. Afterward, resin was bonded to the dentin surface, and 27 beams (1.0 mm × 1.0 mm) of each group were sectioned. One was selected to observe the bonding interface from each group by SEM. Each group was divided into two subgroups (n = 13): 24 hours of water storage (I) and 10,000 thermocycling (A). The microtensile bond strength (µTBS), failure modes and nanoleakage expression were evaluated. SEM results showed that the subpressure groups had longer and denser resin tags. The µTBS of the subpressure groups was higher than that of the control group (p < 0.05). The subpressure groups were dominated by mixed failure, whereas main interfacial failure appeared in group C. The subpressure groups showed less silver deposition than the control group (p < 0.05). The subpressure technique may remarkably improve bonding strength and decrease nanoleakage on total-etching bonding.

Effective treatment of ketamine-associated cystitis with botulinum toxin type a injection combined with bladder hydrodistention.

Objective Ketamine-associated cystitis (KAC) has been described in a few case reports, but its treatment in a relatively large number of patients has not been documented. This study aimed to describe our experience of treatment of 36 patients with KAC. Methods Thirty-six patients (30 males and 6 females, aged 19-38 years) with KAC, who had previously taken a muscarinic receptor blocker and/or antibiotics, but without symptomatic relief, were treated with botulinum toxin A injection combined with bladder hydrodistention. Urodynamic testing, and the O'Leary-Sant interstitial cystitis symptom index (ICSI) and problem index (ICPI) were used to evaluate baseline values and improvement before and after the treatment. Results One month post-treatment, all patients achieved marked relief of symptoms. The nocturia time was markedly reduced, while bladder capacity, the interval between micturition, the void volume, and the maximum flow rate were remarkably increased at 1 month. Additionally, the ICSI and ICPI were significantly improved. Conclusion Botulinum toxin A injection along with bladder hydrodistention is effective for managing KAC.

Effect of airborne-particle abrasion of presintered zirconia on surface roughness and bacterial adhesion.

STATEMENT OF PROBLEM: Factors associated with implant periodontal disease of zirconia restorations such as surface roughness remain largely unknown. PURPOSE: The purpose of this study was to investigate how airborne-particle abrasion before sintering affects roughness and bacterial adhesion on the surface of zirconia. MATERIAL AND METHODS: Thirty presintered zirconia specimens were divided into 6 groups of 5 after being polished with silicon carbide paper (1200 grit). A different surface treatment was applied to each group (no treatment [group Ct] and 120-µm alumina abrasion for 5, 8, 10, 12, and 15 seconds [A5s, A8s, A10s, A12s, and A15s]), and the specimens were then densely sintered. The mean centric linear roughness (Ra) was measured, and the 3D measurement of surface roughness (3D roughness) was determined. The number of colony forming units (CFUs) of Streptococcus mutans adhering to the surface was also examined. One-way ANOVA was used for data analysis (α=.05). RESULTS: Airborne-particle abrasion before sintering significantly increased surface roughness. Group A8s, A10s, A12s, and A15s showed statistically significant higher CFU/mL than did group A5s (P<.05). No difference was found in CFU/mL between group Ct and A5s (P=.230). CONCLUSIONS: Airborne-particle abrasion before sintering is a useful method of increasing the surface roughness of zirconia. Ra < 0.58 µm is necessary to inhibit the adherence of S. mutans to zirconia.

Effect of sandblasting on surface roughness of zirconia-based ceramics and shear bond strength of veneering porcelain.

This study aims to investigate the effect of sandblasting on the surface roughness of zirconia and the shear bond strength of the veneering porcelain. Pre-sintered zirconia plates were prepared and divided into four groups. Group A were not treated at all; group B were first sandblasted under 0.2 MPa pressure and then densely sintered; group C and D were sintered first, and then sandblasted under 0.2 MPa and 0.4 MPa pressures respectively. Surface roughness was measured and 3D roughness was reconstructed for the specimens, which were also analyzed with X-ray diffractometry. Finally after veneering porcelain sintering, shear bond tests were conducted. Sandblasting zirconia before sintering significantly increased surface roughness and the shear bond strength between zirconia and veneering porcelain (p<0.05). Sandblasting zirconia before sintering is a useful method to increase surface roughness and could successfully improve the bonding strength of veneering porcelain.

Effects of clasp retention forces and abrasion on different cast crowns.

STATEMENT OF PROBLEM: Dental alloys have different mechanical properties compared with enamel. However, few studies have been conducted to determine the effects of the retention forces of clasps when applied on different cast crowns. PURPOSE: The purpose of this study was to evaluate the retention forces of cast circumferential clasps made of cobalt-chromium alloy on complete cast crowns made of cobalt-chromium (CC group) and gold-silver-palladium (AC group) alloys, and to observe their abrasion patterns. MATERIAL AND METHODS: Two groups of specimens were fabricated (n=5) and subjected to repeated insertion-removal tests (100 to 15,000 cycles). The mean values of removal forces at 100, 400, 800, 1500, 4500, 7500, 10,000, and 15,000 cycles, and their corresponding change rates compared with the initial 100 cycles' retention were determined. The differences between the 2 groups were analyzed by 2-way repeated measures analysis of variance at 100, 7500, and 15,000 cycles. The surfaces of specimens were observed with scanning electron microscopy. RESULTS: There were significant differences between the CC and AC groups in retention forces (P<.05). Clasp retention showed a descending trend for cobalt-chromium alloy crowns from the initial value, which decreased by 29.9% after 15,000 insertion-removal cycles. A sharp increase in retention could be observed in the AC group, which rose by 99.7% ultimately. The worn surfaces of the gold-silver-palladium crowns showed different wear patterns compared with the cobalt-chromium alloy crowns. CONCLUSIONS: The results indicate that cobalt-chromium alloy crowns and gold-silver-palladium alloy crowns perform differently when cobalt-chromium alloy clasps are designed as retainers for partial removable dental prostheses. Crown designs should be changed, depending on the retainer and clasp materials for partial removable dental prostheses abutment teeth.

Improvement in Ti-porcelain bonding by SiO(2) modification of titanium surface through cast method.

This study aimed to improve Ti-porcelain bonding strength through SiO2 modifications. Wax patterns were coated with SiO2 mixed with tetraethoxy silane (group C), patterns without coating were used as controls and subdivided into sandblasting group (group S) and polishing group (group P). Castingsurfaces were analyzed with XRD, while Ti-ceramic interfaces were characterized using SEM/EDS. Metal-ceramic specimens were tested in three point bending, and characterizations were also analyzed with SEM/EDS of porcelain debonding surfaces. In group C, SiO2 and Ti5Si3 phases were observed; SEM micrograph showed that Ti-porcelain had a compacted interface, and EDS maps of the interface illustrated the diffusion of Si, Al, and Sn to Ti, and cohesive fracture within the bonding agent. The bond strength of group C was 39.04±5.0 MPa, which was 15% higher than that of group S and 32% higher than that of group P. SiO2 coating could improve Ti-porcelain bond strength.

[Influence of reducing buccolingual width of artificial crown of implant prosthesis on distribution of biting force and masticatory efficiency].

OBJECTIVE: To discuss the influence of reducing buccolingual width of artificial crown on distribution of biting force and masticatory efficiency in unilateral distal-extension implant denture and provide valuable information for the design of buccolingual width. To find a design that the biting force of implant prothesis was less evident than those on the contralateral natural teeth without compromising masticatory efficiency. METHODS: T-Scan II occlusal analyzer and 722 grating spectrophotometer were used to analyze the distribution of biting force and masticatory efficiency in unilateral distal-extension implant denture. Heat-cured resin crowns with three different buccolingual width (group A: standard buccolingual width; group B: the buccolingual width was reduced by 1/4; group C: the buccolingual width was reduced by 1/3) were designed as follow, one was contoured with standard buccolingual width, the other two were made with reducd buccolingual width by 1/4 and 1/3. RESULTS: The ratio of biting force (ROF) of group C was 16.25%, which was significantly lower than group A (27.38%) and B (22.60%) (P < 0.0083). The X axis displacement of center of occlusal force (COF) of group C was 2.0 mm, which was significantly difference with group A (1.5 mm, P = 0.004). The masticatory efficiency absorbance A value (MEA) of group C was 0.217, which was significantly lower than group A (0.345, P = 0.005) and B (0.289, P = 0.004). CONCLUSIONS: According to the study, the buccolingual width of the crown reduced by 1/4 was a more ideal design for unilateral distal-extension implant denture.