scholarly journals Clinical Evaluation of Time Efficiency and Fit Accuracy of Lithium Disilicate Single Crowns between Conventional and Digital Impression

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5467
Author(s):  
Ji-Su Park ◽  
Young-Jun Lim ◽  
Bongju Kim ◽  
Myung-Joo Kim ◽  
Ho-Beom Kwon
Keyword(s):  
Conventional Method ◽  
Statistical Tests ◽  
Statistical Significance ◽  
Lithium Disilicate ◽  
Digital Impression ◽  
Time Efficiency ◽  
Digital Dentistry ◽  
Single Crown ◽  
Significant Difference ◽  
Single Crowns

The purpose of this study was to demonstrate the time-efficiency and the clinical effectiveness of chairside-fabricated lithium disilicate single crowns by digital impressions compared to the conventional method. Thirteen patients requiring a single crown on the maxillary or mandibular premolar or first molar were assigned as study subjects. The impressions were obtained using the conventional method and two digital methods with intraoral scanners: AEGIS.PO (Digital Dentistry Solution, Seoul, Korea) and CEREC Omnicam (Sirona, Bensheim, Germany). Two types of lithium disilicate single crowns were obtained; a reference crown (by conventional workflow) and a chairside crown (by digital workflow). The total time taken for fabricating the chairside crown was recorded. The replica technique was performed to compare the marginal and internal fit of the two types of crowns. In addition, accuracy of the intraoral scanners was evaluated by the best-fit alignment method. The difference between the groups was analyzed using the two-tailed paired t-test or one-way ANOVA, followed by the Student–Newman–Keuls test for multiple comparisons. Statistical significance was accepted at p < 0.05 for all statistical tests. The time required to obtain the impressions by the AEGIS (7:16 ± 1:50 min:s) and CEREC (7:29 ± 2:03 min:s) intraoral scans was significantly lower than the conventional method (12:41 ± 1:16 min:s; p < 0.001). There was no significant difference between the intraoral scanners. The total working time to fabricate the chairside crown averaged 30:58 ± 4:40 min:s. The average marginal gap was not significantly different between the reference (107.86 ± 42.45 µm) and chairside (115.52 ± 38.22 µm) crowns (p > 0.05), based on results of replica measurement. The average internal gaps were not significantly different. The average value of the root mean square between the AEGIS (31.7 ± 12.3 µm) and CEREC (32.4 ± 9.7 µm) scans was not significantly different (p > 0.05). Intraoral scans required a significantly shorter impression time than the conventional method, and it was possible to fabricate a lithium disilicate crown in a single visit. There were no statistically significant differences in the fit of the restorations and accuracy of the intraoral scanners compared to the conventional workflow.

scholarly journals Lithium disilicate and peek implant-retained single crowns - a randomized, prospective clinical study

2022 ◽  
pp. 3-3
Author(s):  
Ena Joksimovic ◽  
Miodrag Scepanovic ◽  
Danijela Staletovic ◽  
Mirjana Pejic-Duspara ◽  
Borivoj Bijelic ◽  
...  
Keyword(s):  
Statistical Significance ◽  
Lithium Disilicate ◽  
Observation Time ◽  
Control Group ◽  
Prospective Clinical Study ◽  
Tissue Healing ◽  
Significant Difference ◽  
Comparison Of The Results ◽  
And Control ◽  
Single Crowns

Introduction/Objective. Comparing two materials under the same conditions is the best way to define differences between them. PEEK is a polymer that has many possible uses in dentistry as already well-known lithium disilicate ceramics. The aim of this study was to compare peri-implant soft tissue healing and evaluate patient satisfaction with esthetics in different observation periods, as well as the success and survival rate of both types of crowns. Methods. The study was conducted as a clinical, prospective, randomized split-mouth study on 17 patients with bilaterally missing upper teeth of the same type, replaced with dental implants. Study outcomes have been analyzed with subjective (VAS scale) and objective parameters (MBI, MPI and PPD) baseline, six and twelve months after fixing crowns onto the implants. Results. Comparison of the results between PEEK and lithium disilicate crowns showed no statistical differences in terms of MPI, MBI and PPD in the observed periods. Analyzing MPI during observation periods in the PEEK group of crowns, statistical significance was registered between baseline values and after 6 months. Also, statistical significance was noticed in terms of PPD during the observation time both in the study and control group of crowns. Results for VAS for the esthetics showed no statistically significant difference between the groups, while VAS for restoration satisfaction showed a statistically significant difference. Conclusion. This study showed that scores of the applied subjective and objective parameters can be a reliable tool to rate the clinical outcome of implant-retained single crowns over time.

scholarly journals Does Resin Cement Type and Cement Preheating Influence the Marginal and Internal Fit of Lithium Disilicate Single Crowns?

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 424
Author(s):  
Nourhan Samy ◽  
Walid Al-Zordk ◽  
Ahmed Elsherbini ◽  
Mutlu Özcan ◽  
Amal Abdelsamad Sakrana
Keyword(s):  
Lithium Disilicate ◽  
Resin Cement ◽  
The Other ◽  
Cement Type ◽  
Finish Line ◽  
Marginal Fit ◽  
Single Crown ◽  
Significant Difference ◽  
Internal Fit ◽  
Single Crowns

This paper assesses the effect of cement type and cement preheating on the marginal and internal fit of lithium disilicate single crown. Methods: 40 maxillary premolars were selected, restored with lithium disilicate single crowns. Teeth were randomly assigned into four groups (n = 10) based on cement type (Panavia SA or LinkForce) and preheating temperature (25 °C or 54 °C). After fabrication of the restoration, cements were incubated at 25 °C or 54 °C for 24 h, and each crown was cemented to its corresponding tooth. After 24 h, all specimens were thermally aged to (10,000 thermal cycles between 5 °C and 55 °C), then load cycled for 240,000 cycles. Each specimen was then sectioned in bucco-palatal direction and inspected under a stereomicroscope at x45 magnification for marginal and internal fit evaluation. The data were statistically analyzed (significance at p ≤ 0.05 level). Results: At the mid-buccal finish line, mid-buccal wall, palatal cusp, mid-palatal wall, mid-palatal finish line, and palatal margin measuring points, there was a significant difference (p ≤ 0.05) between the lithium disilicate group cemented with Panavia SA at 25 °C and the group cemented with LinkForce at 25 °C, while there was no significant difference (p > 0.05) at the other points. At all measuring points, except at the palatal cusp tip (p = 0.948) and palatal margin (p = 0.103), there was a statistically significant difference (p ≤ 0.05) between the lithium disilicate group cemented with Panavia SA at 54 °C and the group cemented with LinkForce at 54 °C. Regardless of cement preheating, statistically significant differences were found in the buccal cusp tip, central groove, palatal cusp tip, and mid-palatal wall (p ≤ 0.05) in the lithium disilicate group cemented with Panavia SA at 25 °C and 54 °C, as well as the mid-palatal chamfer finish line and palatal margin in the LinkForce group cemented with Panavia SA at 25 °C and 54 °C. At the other measurement points, however, there was no significant difference (p > 0.05). Conclusions: The type of resin cement affects the internal and marginal fit of lithium disilicate crowns. At most measuring points, the cement preheating does not improve the internal and marginal fit of all lithium disilicate crowns.

scholarly journals CircaCompare: a method to estimate and statistically support differences in mesor, amplitude and phase, between circadian rhythms

2019 ◽  
Author(s):  
Rex Parsons ◽  
Richard Parsons ◽  
Nicholas Garner ◽  
Henrik Oster ◽  
Oliver Rawashdeh
Keyword(s):  
Wave Function ◽  
Statistical Tests ◽  
Statistical Significance ◽  
P Value ◽  
Cross Sectional ◽  
Fundamental Interest ◽  
Response Variable ◽  
Highly Sensitive ◽  
Significant Difference ◽  
Phase Amplitude

Abstract Motivation A fundamental interest in chronobiology is to compare patterns between groups of rhythmic data. However, many existing methods are ill-equipped to derive statements concerning the statistical significance of differences between rhythms that may be visually apparent. This is attributed to both the form of data used (longitudinal versus cross-sectional) and the limitations of the statistical tests used to draw conclusions. Results To address this problem, we propose that a cosinusoidal curve with a particular parametrization be used to model and compare data of two sets of observations collected over a 24-h period. The novelty of our test is in the parametrization, which allows the explicit estimation of rhythmic parameters [mesor (the rhythm-adjusted mean level of a response variable around which a wave function oscillates), amplitude and phase], and simultaneously testing for statistical significance in all three parameters between two or more groups of datasets. A statistically significant difference between two groups, regarding each of these rhythmic parameters, is indicated by a P-value. The method is evaluated by applying the model to publicly available datasets, and is further exemplified by comparison to the currently recommended method, DODR. The results suggest that the method proposed may be highly sensitive to detect rhythmic differences between groups in phase, amplitude and mesor. Availability and implementation https://github.com/RWParsons/circacompare/

scholarly journals In vitro study of marginal, internal and proximal adaptation of implant-supported single-crown CAD/CAM restorations

2020 ◽  
Vol 19 ◽  
pp. e207286
Author(s):  
Kamila Aguiar Figueiredo Alves ◽  
Janaina Emanuela Damasceno ◽  
Viviane Maia Barreto de Oliveira ◽  
Luiz Gustavo Cavalcanti Bastos ◽  
Andrea Nóbrega Cavalcanti
Keyword(s):  
Repeated Measures ◽  
T Test ◽  
Digital Impression ◽  
Single Crown ◽  
Significant Difference ◽  
Cad Cam ◽  
Student’S T ◽  
One Way Anova ◽  
Student’S T Test

Aim: This study evaluated the precision of a CAD/CAM system by measuring marginal, internal and proximal fits in implantsupported single-crown restorations. Methods: Ten models of the upper arch were made in which implants replaced the upper left premolars. For fabrication of the zirconia infrastructures, titanium bases (TiBase) were coded and scanned using a scan body. A second digital impression was made for the fabrication of prostheses. Silicone impression material was used to determine the internal clearance between the TiBase and infrastructure and between the infrastructure and crown, whose thickness was measured at three points [P1 (cervical), P2 (middle) and P3 (occlusal)] with a stereoscopic microscope at 70x and 100x magnification. One-way ANOVA for repeated measures and the Student t-test were used for the analysis of internal and marginal adaptation. Proximal contacts were analyzed qualitatively. Results: There was no significant difference between the teeth evaluated (Student’s t-test; p>0.05) or between the corresponding points evaluated in either tooth (one-way ANOVA; p>0.05). Analysis of the internal clearance between the infrastructure and crown demonstrated that all points were significantly different compared to the reference standardized at 100 μm (Student’s t-test p<0.0001). There was no significant difference between P1 and P2, with the thickness at these two points being lower than that obtained at P3 (one-way ANOVA, p<0.05). The proximal contacts did not coincide with the quality defined by the device. Conclusion: The system tested was unable to produce implantsupported single-crown ceramic restorations with marginal, internal and proximal fits matching the digital workflow, with the inferior fits requiring adjustment prior to cementation.

scholarly journals Who indicates Caesarean section in Romania? A cross-sectional survey in tertiary level maternity on childbirth patients and doctors' profiles 

2020 ◽  
Author(s):  
Anca Angela Simionescu ◽  
Alexandra Horobet ◽  
Erika Marin ◽  
Lucian Belascu
Keyword(s):  
Statistical Tests ◽  
Statistical Significance ◽  
Tertiary Level ◽  
The European Union ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Significant Difference ◽  
Mode Of Birth ◽  
High Income Category ◽  
Women’S Preferences

Abstract Background. Cesarean section (C-section) rate in Romania is the second-highest in the European Union (44.1% in 2017), and the number of C-sections performed in the country has increased in the past decades. Given how common C-section is now, it is important to gain insight into the practice and perceptions of patients and doctors in countries with high C-section rates. The objectives are 1) to compare the preferred modes of birth among women; 2) to draw a profile of patients and doctors in whose case the actual birth method is different from the preferred method; and 3) to analyze the way Romanian women want to give birth. Methods. We conduct a statistical analysis based on an observational, analytical, and cross-sectional survey on 117 singleton pregnant women more than 36 weeks in spontaneous labor in tertiary level maternity in Romania. Various statistical tests have been used to indicate statistical significance. Results. We calculate an increase of almost 58% in actual childbirth mode against preferred childbirth by C-sections, rather difficult to justify based only on medical emergencies. There are 22 patients with non-concordant C-section indications between preferred and actual mode of birth, 7 of them (31.8%) preferred natural birth and 15 (68.2%) preferred C-section. The profiles of patients with concordant and non-concordant delivery modes are different and indicate a statistically significant difference between the preference for delivery and actual birth method. Patients who preferred vaginal birth, but gave birth by C-section, are mature and more educated women, in the middle to high-income category, mostly attended by consultant doctors and specialists. Doctors’ profiles show that specialists and consultants attend the largest share of non-concordant births, while residents and young senior doctors attend mostly vaginal births. Conclusions. We emphasize health system particularities in Romania as triggers of high C-section rates that favor women’s preferences against C-section medical indication. Improving patients’ confidence in the health care system, built on competence and fitted hierarchical team position may lead to choosing the optimal way of birth for childbirth safety and pain control.

Who Indicates Caesarean Section in Romania? A Cross-Sectional Survey in Tertiary Level Maternity on Childbirth Patients and Doctors' Profiles

2020 ◽  
Author(s):  
Anca Angela Simionescu ◽  
Alexandra Horobet ◽  
Erika Marin ◽  
Lucian Belascu
Keyword(s):  
Health System ◽  
Statistical Tests ◽  
Statistical Significance ◽  
Tertiary Level ◽  
Delivery Mode ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Medical Indication ◽  
Delivery Modes ◽  
Significant Difference

Abstract Background. C-section rate in Romania is the second-highest in the European Union (44.1% in 2017) and the number of C-sections performed in the country increased by 32.1% between 2009 and 2017. We offer for the first time insights into the practice and perceptions of patients and doctors in Romania towards delivery mode and on health system particularities that lead to increased numbers of C-sections. The objectives are 1) to compare the preferred modes of birth among women 2) to draw a profile of patients in whose case the actual birth method is different from the preferred method, and 3) to outline a profile of doctors and patients based on the modes of delivery. Methods. We conduct a statistical analysis based on an observational, analytical, and cross-sectional survey on 117 singleton pregnant women more than 36 weeks in spontaneous labor in tertiary level maternity in Romania. Various statistical tests have been used to indicate statistical significance. Results. Our results show an increase of almost 58% in actual childbirth mode against preferred childbirth by C-sections, rather difficult to justify based only on medical emergencies. There are 22 patients with non-concordant C-section indications between preferred and actual mode of birth, 7 of them (31.8%) preferred natural birth and 15 (68.2%) preferred C-section. Scarred uterus is the most frequent medical indication for C-section (30.7%). Overall, birth and birth pain assessment correlates to preferred and actual delivery modes, but respondents distinguish clearly between birth pain alone and their overall birth experience. The profiles of patients with concordant and non-concordant delivery modes are different, and indicate a statistically significant difference between the preference for delivery and actual birth method. Patients who preferred vaginal birth, but gave birth by C-section, are mature and more educated women, in the middle to the high-income category, mostly attended by consultant doctors and specialists. Doctors’ profiles show that specialists and consultants attend the largest share of non-concordant births, while residents and young senior doctors attend mostly vaginal births. Conclusions. We emphasize health system particularities in Romania as triggers of high C-section rates that favor womens’ preferences against C-section medical indication.

scholarly journals Who indicates Caesarean section in Romania? A cross-sectional survey in tertiary level maternity on childbirth patients and doctors' profiles 

2020 ◽  
Author(s):  
Anca Angela Simionescu ◽  
Alexandra Horobet ◽  
Erika Marin ◽  
Lucian Belascu
Keyword(s):  
Statistical Tests ◽  
Statistical Significance ◽  
Tertiary Level ◽  
The European Union ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Significant Difference ◽  
Mode Of Birth ◽  
High Income Category ◽  
Women’S Preferences

Abstract Background. Cesarean section (C-section) rate in Romania is the second-highest in the European Union (44.1% in 2017), and the number of C-sections performed in the country has increased in the past decades. Given how common C-section is now, it is important to gain insight into the practice and perceptions of patients and doctors in countries with high C-section rates. The objectives are 1) to compare the preferred modes of birth among women; 2) to draw a profile of patients and doctors in whose case the actual birth method is different from the preferred method; and 3) to analyze the way Romanian women want to give birth. Methods. We conduct a statistical analysis based on an observational, analytical, and cross-sectional survey on 117 singleton pregnant women more than 36 weeks in spontaneous labor in tertiary level maternity in Romania. Various statistical tests have been used to indicate statistical significance. Results. We calculate an increase of almost 58% in actual childbirth mode against preferred childbirth by C-sections, rather difficult to justify based only on medical emergencies. There are 22 patients with non-concordant C-section indications between preferred and actual mode of birth, 7 of them (31.8%) preferred natural birth and 15 (68.2%) preferred C-section. The profiles of patients with concordant and non-concordant delivery modes are different and indicate a statistically significant difference between the preference for delivery and actual birth method. Patients who preferred vaginal birth, but gave birth by C-section, are mature and more educated women, in the middle to high-income category, mostly attended by consultant doctors and specialists. Doctors’ profiles show that specialists and consultants attend the largest share of non-concordant births, while residents and young senior doctors attend mostly vaginal births. Conclusions. We emphasize health system particularities in Romania as triggers of high C-section rates that favor women’s preferences against C-section medical indication. Improving patients’ confidence in the health care system, built on competence and fitted hierarchical team position may lead to choosing the optimal way of birth for childbirth safety and pain control.

scholarly journals Research on zinc blood levels and nutritional status in adolescents with autoimmune hepatitis

2011 ◽  
Vol 48 (1) ◽  
pp. 62-65 ◽  
Author(s):  
Thalita Cremonesi Pereira ◽  
Margareth L. G. Saron ◽  
Wagner Alves de Carvalho ◽  
Maria Marluce Vilela ◽  
Nelci Fenalti Hoehr ◽  
...  
Keyword(s):  
Nutritional Status ◽  
Autoimmune Hepatitis ◽  
Zinc Deficiency ◽  
Statistical Tests ◽  
Statistical Significance ◽  
Zinc Level ◽  
Control Group ◽  
Blood Levels ◽  
Significance Level ◽  
Significant Difference

CONTEXT: Zinc deficiency in children and adolescents impairs their growing, development and immune system. OBJECTIVE: To verify the existence of plasma and leukocyte zinc deficiency in adolescents with autoimmune hepatitis. METHODS: The study comprised 23 patients with autoimmune hepatitis, aged 10-18 years, assisted at the Ambulatory Service of Pediatric Hepatology of the University of Campinas Teaching Hospital, Campinas, SP, Brazil, and adolescents with ages compatible with the patients' ages comprised the control group. Sample of blood in both groups was collected for the analyses of plasma zinc and leukocyte zinc by atomic absorption spectrophotometry, beyond the nutritional status was evaluated in each adolescent. The following statistical tests were used: Mann-Whitney, Spearman's correlation and interclass concordance analysis. RESULTS:The significance level adopted was 5%. The average zinc level in plasma in patients was 71.91 ± 11.79 µg/dL and, in the control group, it was 80.74 ± 10.92 µg/dL, showing a significant difference (P = 0.04). The leukocyte zinc level in patients was 222.33 ± 166.13 pmol/10(6) cells and, in the control group, it was 226.64 ± 217.81 pmol/10(6) cells; there was no statistical significance between them (P = 0.45). CONCLUSION:The evaluation of the nutritional status showed that eutrophy is prevalent in patients, and they presented a higher body fat value than the control group, with a significant difference. More research is needed with adolescents with autoimmune hepatitis regarding levels of essential micronutrients, such as zinc, because a good nutritional status can improve the prognostic of liver disease.

scholarly journals Comparison of two therapeutic protocols in patients with antiphospholipid antibodies and recurrent miscariages

2005 ◽  
Vol 62 (6) ◽  
pp. 435-439 ◽  
Author(s):  
Katarina Jeremic ◽  
Miroslava Pervulov ◽  
Miroslava Gojnic ◽  
Jelena Dukanac ◽  
Aleksandar Ljubic ◽  
...  
Keyword(s):  
Intravenous Immunoglobulin ◽  
Pregnancy Outcomes ◽  
Antiphospholipid Antibodies ◽  
Statistical Tests ◽  
Statistical Significance ◽  
Anticardiolipin Antibodies ◽  
Heparin Group ◽  
Significant Difference ◽  
Therapeutic Protocols ◽  
In Pregnancy

Aim. To compare the effects of two therapeutic protocols for the patients with recurrent miscarriages associated with the presence of antiphospholipid (anticardiolipin) antibodies. Methods. A prospective observational study included 20 patients with antiphospholipid antibodies in the first group who received low-molecular heparin and aspirin. The second group of 20 patients, in addition to this therapy, received immunotherapy (intravenous immunoglobulin). Aspirin was administered at the time of a positive pregnancy test, and low molecular heparin not before the fetal heart activity registration by ultrasound. Intravenous immunoglobulin was given prior to the conception or at the beginning of the pregnancy. We compared these groups according to the pregnancy outcomes and the occurrence of complications during pregnancy, using standard statistical tests. Results. The rate of positive gestational outcome in the patients treated with aspirin and low-molecular heparin was 85% (17/20), and in the second group it was 90% (18/20). There was no significant difference in pregnancy outcomes between these groups (p > 0.05), except for the occurrence of preeclampsia and thrombocytopenia, which were recorded only in the aspirin and low-molecular heparin group, but with no statistical significance (p > 0.05) compared to the second group, which received immunoglobulin additionally. Conclusion. There was no significant difference (p > 0.05) in pregnancy outcomes between the two studied therapeutic protocols, but the therapy with aspirin and low-molecular heparin was cheaper and easier to apply than the therapy with immunoglobulins. The results of our study confirmed that the final pathogenic mechanisms in recurrent fetal miscarriages were inflammation and thrombosis of the uteroplacental blood vessels.

Survival of Short and Ultra-Short Locking-Taper Implants Supporting Single Crowns in the Posterior Mandible: A 3-Year Retrospective Study

2020 ◽  
Vol 46 (4) ◽  
pp. 396-406 ◽  
Author(s):  
Giorgio Lombardo ◽  
Annarita Signoriello ◽  
Miguel Simancas-Pallares ◽  
Mauro Marincola ◽  
Pier Francesco Nocini
Keyword(s):  
Retrospective Study ◽  
Bone Loss ◽  
Contact Point ◽  
Implant Survival ◽  
Point Position ◽  
Crestal Bone Loss ◽  
Short Implants ◽  
Single Crown ◽  
Bone To Implant Contact ◽  
Single Crowns

The purpose of this retrospective study was to determine survival and peri-implant marginal bone loss of short and ultra-short implants placed in the posterior mandible. A total of 98 patients received 201 locking-taper implants between January 2014 and January 2015. Implants were placed with a 2-stage approach and restored with single crowns. Clinical and radiographic examinations were performed at 3-year recall appointments. At that time, the proportion of implant survival by length, and variations of crestal bone levels (mean crestal bone loss and mean apical shift of the “first bone-to-implant contact point” position) were assessed. Significance level was set at 0.05. The total number of implants examined 36 months after loading included: 71 implants, 8.0 mm in length; 82 implants, 6.0 mm in length; and 48 implants, 5.0 mm in length. Five implants failed. The overall proportion of survival was 97.51%, with 98.59% for the 8.0-mm implants, 97.56% for the 6.0-mm implants, and 95.83% for the 5.0-mm implants. No statistically significant differences were found among the groups regarding implant survival (P = .73), mean crestal bone loss (P = .31), or mean apical shift of the “first bone-to-implant contact point” position (P = .36). Single-crown short and ultra-short implants may offer predictable outcomes in the atrophic posterior mandibular regions, though further investigations with longer follow-up evaluations are necessary to validate our results.

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