Retention Loss Research Articles

Retentive force variations in three polyamide and a polyetheretherketone denture attachments for implant-supported overdentures: An in vitro study

Statement of problemThe loss in the retentive capability of implant-supported overdenture attachments has been related to the wear of the retentive inserts. Wear of the abutment coating material when following the replacement period for the retentive inserts requires investigation. PurposeThe purpose of this in vitro study was to compare the changes in retentive force of 3 polyamide and a polyetheretherketone denture attachments under repeated insertion and removal cycles in wet conditions while following their manufacturers’ replacement time recommendations. Material and methodsFour different denture attachments (LOCKiT, OT-Equator, Ball attachment, and Novaloc) with their retentive inserts were tested. Four implants were embedded into individual acrylic resin blocks, and 10 abutments for each attachment were used. Forty metal housings with their retentive inserts were attached to polyamide screws with autopolymerizing acrylic resin. A customized universal testing machine was used to simulate insertion and removal cycles. The specimens were mounted on a second universal testing machine at 0, 540, 2700, and 5400 cycles, and the maximum retentive force was recorded. The retentive inserts for LOCKiT (light retention), OT-Equator (soft retention), and Ball attachment (soft retention) were replaced every 540 cycles, while the Novaloc (medium retention) attachments were never replaced. All the abutments were weighed with a precision scale at 0, 2700, and 5400 cycles. The surface of every abutment was examined under a stereomicroscope at ×10 magnification. Data were analyzed with descriptive statistics. Two-way repeated measures ANOVA was used to compare the mean retentive force and mean abutment mass of all groups and time evaluation points. Bonferroni corrections were made to adjust for multiple tests (α=.05). ResultsThe mean retention loss for LOCKiT was 12.6% after 6 months and 45.0% after 5 years of simulated use. The mean retention loss for OT-Equator was 16.0% after 6 months and 50.1% after 5 years of simulated use. The mean retention loss for Ball attachment was 15.3% after 6 months and 39.1% after 5 years of simulated use. The mean retention loss for Novaloc was 31.0% after 6 months and 59.1% after 5 years of simulated use. The mean abutment mass difference was statistically significant (P<.05) for LOCKiT and Ball attachment but not statistically significant (P>.05) for OT-Equator and Novaloc at baseline, 2.5 years, and 5 years. ConclusionsAll tested attachments recorded retention loss under the experimental conditions, even when their manufacturers’ recommendations for replacement time for the retentive inserts were followed. Patients should be aware that implant abutments should be replaced after a recommended period since their surfaces also change over time.

Methodological Approach to Managing Customer Experience in the IT Services Market

The role of the client in ensuring the competitiveness of companies is increasing. This becomes the reason for the increase of innovative activity of companies. The ability to create technology products with maximum customer value become key factor of competitiveness.The aim of the study is to develop a methodical approach to the management of client experience in innovative companies. The methodical approach should solve the problem of loss of potential clients and retention of existing clients. Scientific novelty of research consists in formation of methodical approach, which is based on complex perception of client experience. The practical significance of the study lies in the possibility of using its results to analyze the state of management of client experience in a small company.The article uses such research methods as data collection, information processing and analysis, method of generalization and classification and the method of definition of concepts. The key result of the study is a comprehensive methodical approach to the management of client experience. The developed approach takes into account the specifics of IT companies and the market of IT services and compensates for the shortcomings of traditional methods of management of client experience. The prospect of using customer experience management in the B2B segment is justified by the increase in the conversion rate for the analyzed period and the increase in the number of repeated sales in the object of the study (Azoft).

Influence of Denture Cleansers on the Retention Loss of Attachment Systems Retained Implant Overdenture.

This study aimed to evaluate the effects of different denture cleansing solutions (DCSs) on the retention of Locator and Locator R-Tx attachment systems of implant retained overdentures (IRO). Two part acrylic resin blocks were fabricated, upper part contained metal housing and plastic inserts and lower part contained implant analogs and abutments. Eighty pink plastic inserts (40/attachment, 10/solution) were immersed in Corega, Fittydent, sodium hypochlorite, and water for a time simulating upto 1-year of clinical usage. Acrylic blocks were held on a universal testing machine for a pull-out test to record the dislodgement force. Measurements were conducted after 6 months (T1) and 12 months (T2). One-way ANOVA followed by Tukey's HSD test was used to analyze the results (α = 0.05). For both attachments, retention significantly decreased after immersion in different solutions at T2 (P < 0.001). Locator R-Tx attachment in NaOCl showed a significant decrease in retention compared with other solutions at T1. At T2, there was a significant decrease in retention for all DCS compared with water (P < 0.001). Locator R-TX showed higher retention values per solution compared to Locator attachment (P < 0.001). In terms of retention loss %, NaOCl recorded the highest (61.87%) loss, followed by Corega (55.54%) and Fittydent (43.13%), whereas water demonstrated the best retention (16.13%) in both groups. Locator R-TX has better retention with different DCS immersion. The loss of retention varied with different types of DCS and NaOCl recorded the highest retention loss. Therefore, denture cleanser selection must be guided by the type of IRO attachment.

An In-vitro Evaluation of Retention Force of All PEEK, All Zirconia and Zirconia-PEEK Telescopic Attachment for Mandibular Overdentures.

The objective of this study is to compare retention capacity of mandibular implant-supported overdenture with all zirconia, zirconia-PEEK, and all PEEK telescopic attachments. Sixty acrylic resin models of mandible were used. Telescopic attachment system was made up of all zirconia, all PEEK, and zirconia-PEEK. Evaluation of retention force was done using universal testing machine. Obtained data were statistically evaluated. Highest initial force value was obtained with zirconia-PEEK group. All PEEK and zirconia-PEEK groups showed significantly decreased final retention values in comparison to their initial values. Zirconia can be regarded as the material of choice for telescopic crown, whereas polyetheretherketone and zirconia-PEEK telescopic crowns showed retention loss over a period of time.

Need for restoration of non-carious cervical lesions – A literature review

In present scenario, restoring non-carious cervical lesions (NCCLs) is clinically common. Major reasons for this are increased elderly population, the decreasing levels of tooth loss, and possible increase in the etiologies. These factors are poor brushing technique due to which gums recede, consumption of corrosive foods and beverages, and occlusal stress concentrators (occlusal disorders, premature contact, clenching, and bruxism habits. Unfortunately, Class V restorations are known to be less durable type and they have high index of retention loss, marginal residues and secondary caries. Other problems include isolation, insertion, cutting, finishing, and polishing. The present work aims to help the dentist choose best treatment strategy, which mainly involves the stages of problem identification, diagnosis, elimination or etiological treatment and if require restoration. Finally, appropriate recovery methods are suggested for each situation.

Selective Disruption of Perineuronal Nets in Mice Lacking Crtl1 is Sufficient to Make Fear Memories Susceptible to Erasure

The ability to store, retrieve, and extinguish memories of adverse experiences is an essential skill for animals’ survival. The cellular and molecular factors that underlie such processes are only partially known. Using chondroitinase ABC treatment targeting chondroitin sulfate proteoglycans (CSPGs), previous studies showed that the maturation of the extracellular matrix makes fear memory resistant to deletion. Mice lacking the cartilage link protein Crtl1 (Crtl1-KO mice) display normal CSPG levels but impaired CSPG condensation in perineuronal nets (PNNs). Thus, we asked whether the presence of PNNs in the adult brain is responsible for the appearance of persistent fear memories by investigating fear extinction in Crtl1-KO mice. We found that mutant mice displayed fear memory erasure after an extinction protocol as revealed by analysis of freezing and pupil dynamics. Fear memory erasure did not depend on passive loss of retention; moreover, we demonstrated that, after extinction training, conditioned Crtl1-KO mice display no neural activation in the amygdala (Zif268 staining) in comparison to control animals. Taken together, our findings suggest that the aggregation of CSPGs into PNNs regulates the boundaries of the critical period for fear extinction.

Experimental study on affordable thermal insulation of exhaust manifolds using modified sheep wool waste

Internal Combustion (I.C.) engines generate lot of heat during high-speed operations. In order to prevent this heat loss, thermal insulation is mandatory to prevent heat transfer from the exhaust to the adjacent parts. The main aim of this work is to develop a thermally insulating material placed inside the catalytic converter to block the withdrawal of heat from the converter. This insulating material is usually placed between the heat shields for better heat dissipation. Comparison studies is executed between two different types of insulation material such as conventional Z-mat and super wool at various temperatures ranging from 200 °C to 800 °C for a period of 60 min and distortion results are noted at each temperature. Muffler furnace is used for the heat treatment analysis of the fabricated super wool. The composition of the novel fabricated super wool material can withstand all temperature levels between 200 °C and 800 °C, but the conventional Z-mat is suitable only up to 600 °C, where the Z-mat structure lost its capacity of insulation. Hence, the fabricated super wool material is more suitable for insulating catalytic converters and thereby it enhances the performance of engine with longer durability. In addition, hot vibration test is conducted for a duration of 50 h to check the thermal resistance capability of the super wool material. It is found that the thermal insulation is intact in position with absence of cracks or failures, inlet face erosion and retention losses. The fabricated thermal insulation mats from sheep wool waste also passed thermal shock test performed for 1500 thermal cycles. Thereby, this sort of sheep wool based affordable thermal insulation can be used for applications associated with larger thermal gradients to control the thermal-related errors such as shrinkage, warpage and distortion, which can also be extended to acoustic absorption.

Failure Mechanisms of High-Voltage Spinel LiNi0.5Mn1.5O4 with Different Morphologies: Effect of Self-Regulation by Lithium Benzimidazole Salt Additive

High voltage (∼5 V) spinel LiNi0.5Mn1.5O4 (LNMO) has attracted great attention because of its ultrahigh voltage plateau, which can be used as a cathode to reduce pressure in battery management systems. Moreover, compared with layered LiNxMyCzO2 materials, LNMO only requires little amounts of Ni, is cobalt-free for maintaining energy density, is inexpensive, and is lightweight. This study demonstrates two types of primary particles with different morphologies: rectangular and pentahedral. The pentahedron-shaped LNMO has lower surface energy owing to the formation of high valence Ni on the surface, thereby causing gas evolution and a loss in cycle retention, a direct Ni2+/Ni4+ reaction. Conversely, rectangular-shaped LNMO with higher Mn3+ content exhibits a stable electrochemical reaction, which provides a higher surface energy that prevents ethylene carbonate (EC) decomposition on the surface, and thereby, excellent performance is obtained, a parallel reaction of Mn3+/ Mn4+ and Ni2+/ Ni3+. By adding a lithium salt additive, trifluoromethyl benzimidazole (LiTFB), a self-regulation of Ni and Mn ion valences leads to a key reaction on both pentahedral (surface disordering effect) and rectangular (preventing Jahn–Teller distortion effect) LNMO morphologies. The two-electron transfer in the reactions of Ni2+/3+ and Mn3+/4+ of LiTFB-modified LNMOs provides excellent electrochemical performance for further high-energy applications.

In vitro measurement of the retention force of two stud attachment systems during cyclic load.

To investigate the retentive behavior of the Locator legacy and Novaloc attachment systems with different retention inserts both within and across systems under cyclic load. Three retention inserts of each system (green, yellow, and white for Novaloc; green, orange, and red inserts for extended range for legacy Locator) were tested on abutments of both systems with a sample number of 10 per force and 10,000 cycles of insertion and removal. The loading was applied in the axial direction of the abutments, which were placed in artificial saliva. The retention force was measured in each cycle. The results were compared with the manufacturer's specifications and evaluated for a simulated period of use of 10 years. Characteristic time constants were determined, and subsequently, the two systems were compared regarding their wear behavior. The manufacturer's specifications could only be confirmed for the green Novaloc retention insert on a Novaloc abutment (t-test: p=0.50); for all other inserts, the baseline exceeded the manufacturer's specifications by 30%-75% (Novaloc; t-test: p<0.001) and 75%-550% (Locator; t-test: p<0.001). After 10,000 cycles performed, themanufacturer's specifications were confirmed on a Novaloc abutment for the white Novaloc retention insert (t-test: p=0.86) and on a Locator abutment for the green Novaloc retention insert (t-test: p=0.32). Both systems lost retention force during the experiment. Overall, Novaloc inserts on both abutments showed less wear (decrease to 56%-85% of initial force) and a slower decrease in retention force compared to Locator inserts (decrease to 6%-31% of initial force). In both systems, wear leads to a varying loss of retention; therefore, regular checks with possible replacement of the inserts are necessary in clinical use. Novaloc attachments seem to be more resistant to the loss of retention than Locator attachments. A cross-combination may be clinically useful in some cases.

Numerical Simulation of Trapped Hole Lateral Migration and Induced Threshold Voltage Retention Loss in a SONOS Flash Memory

We establish a one-dimensional transient simulation to study trapped hole lateral migration in the silicon nitride of a silicon-oxide-nitride-oxide-silicon (SONOS) flash memory cell. In our model, the nitride traps have a continuous energy distribution. Trapped hole emissions to the valence band of the silicon nitride, free hole recapture into the nitride traps, and hole drift-diffusion in the valance band are included in the simulation. Two major trapped hole emission processes, thermally assisted tunneling (ThAT) and the Frenkel-Poole emission are considered. We simulate trapped hole lateral migration in a SONOS cell with program electrons stored at the source side and erase holes at the drain side. Our simulation shows that the ThAT is a dominant transport mechanism for trapped hole lateral migration in retention. We also simulate a threshold voltage (Vt) retention loss due to trapped hole lateral migration at different program levels. The trend of the simulated Vt retention loss is consistent with the measurement result.

Effectiveness of the National Diabetes Prevention Program After Gestational Diabetes

Women with previous gestational diabetes are at high risk of developing Type 2 diabetes. The National Diabetes Prevention Program (NDPP) is a widely disseminated lifestyle intervention to prevent Type 2 diabetes. Although NDPP programs are open to adults of any age, participants are usually older adults. Effectiveness among younger women with previous gestational diabetes is largely unknown. The NDPP was delivered by lifestyle coaches in a large network of Federally Qualified Health Centers. Reach, retention, physical activity, and weight loss outcomes were compared between women aged <40 years with previous gestational diabetes and all other participants. Data were collected from 2013 to 2019 and analyzed in 2022. Among 2,865 enrollees who agreed to start the yearlong NDPP, 63.3% were Latinx, 18.8% were non-Latinx Black, and 16.4% were non-Latinx White. Younger women with previous gestational diabetes represented <4% (n=107) of participants. There was no significant difference in the frequency of attending ≥1 NDPP session between these women and all other participants (37.4% vs 44.6%; p=0.146). However, among those attending ≥1 session (n=1,265), younger women with previous gestational diabetes attended more (11.27 ± 1.27 vs 8.50 ± 0.22 sessions, p=0.021) and had greater weight loss (3.04% ± 0.59 vs. 1.49% ± 0.11, p=0.010) in covariate-adjusted models than other participants. Diverse younger women with previous gestational diabetes attending the NDPP had one third greater attendance and twice as much weight loss as other NDPP participants but represented a much smaller proportion of enrollees. Thus, the NDPP appears to be a beneficial but underutilized resource for this high-risk population.

CUSTOMIZED THERMOPLAST RETENTIVE AID FOR PARTIAL AURICULAR PROSTHESIS-A CASE REPORT

Auricular prostheses were traditionally retained using chemical adhesives ,mechanical retentive aids or natural undercuts at retention sites.These methods have the limitation of frequent loss of retention, skin reactions to adhesives, or unnatural movements of the prosthesis. Osseo integrated implants which has superior advantages over others have disadvantages for patients with financial constraints and/or who are apprehensive of surgery.Also, extraoral implants require adequate thickness of bone, which may be deficient in certain cases. In this case report,we have described about a new technique of fabricating and incoporating a customized thermoplastic auricular retentive aid thus utilizing both anatomic and mechanical retention.

Technical Complications of Removable Partial Dentures in the Moderately Reduced Dentition: A Systematic Review.

The aim of this study was to conduct a systematic literature review with a subsequent meta-analysis on the technical complications and failures of removable partial denture (RPD) therapy in the moderately reduced dentition. A systematic literature search of established medical databases, last updated 06/2022, was conducted. RCTs and prospective and retrospective studies were included that had information on technical complications and failures of RPDs, at least 15 participants, an observation period of at least two years and a drop-out rate of less than 25%. Publications were selected on the title, abstract and full-text level by at least three of the participating authors. The evidence of the included studies was classified using the GRADE system. The bias risk was determined using the RoB2 tool and the ROBINS-I tool. Of 19,592 initial hits, 43 publications were included. Predominantly, retention of the prosthesis, retention loss of anchor crowns (decementations), fractures/repairs of frameworks, denture teeth, veneering or acrylic bases, and a need for relining were reported depending on prosthesis type and observation time. Focusing on technical complications and failures, only very heterogeneous data were found and publications with the highest quality level according to GRADE were scarce. Whenever possible, data on technical complications and failures should be reported separately when referencing the tooth, the prosthesis and the patient for comparability. Prostheses with differing anchorage types should be analyzed in different groups, as the respective complications and failures differ. A precise description of the kinds of complications and failures, as well as of the resulting follow-up treatment measures, should be given.

The effect of different denture cleansing solutions on the retention of polyetheretherketone locator attachments.

Prosthetic cleansing solutions have been reported to cause retention loss in implant locator attachments due to the chemical alterations of these attachments. This study aimed to investigate the effects of different denture cleansing solutions on attachments with different retention values. In this study, 160 polyetheretherketone locator attachments were divided into 4 groups according to their attachment retention values (yellow, pink, clear, and violet). Forty attachments from each group were soaked in four different cleansing solutions (n=10). The attachments from the four groups were immersed in water, sodium hypochlorite, Corega, and Protefix solutions for a period equivalent to 6 months, according to the manufacturer's recommendations. The locator attachments were then subjected to testing using a universal testing machine. Maximum load to dislodgement according to different solutions was evaluated by one-way ANOVA test. Statistical significance was set at p<0.05. The effect of denture cleansing solutions on the retentive values of attachments was statistically significant (p<0.001). Among all cleansing solutions, the highest retention value was found in the violet attachments, and the lowest retention value was found in the yellow attachments. The lowest retention value (0.72±0.05MPa) was observed when the yellow attachments were immersed in Protefix solution, and the highest retention value (1.96±0.15MPa) was observed when the violet attachments were immersed in the Corega solution. For different colored attachments, different cleansing solutions can be suggested to patients.

Optimization of Vacuum Marination Process, Maximizing the Flavor Infusion of Sole Fish

The major problem facing the fish processing industry is reducing the marination process time and increasing the uptake of marinade. Previously, a marination bath has been utilized for this purpose with different combinations of acid and salt, which causes physiochemical changes in fish texture. The vacuum marination method seems to be a good way to solve this problem. In this study, the effect of the vacuum marination process was studied on the marination of sole fish. Two varieties of fish (fresh and frozen) and three levels of time (10, 20 and 30 minutes) were studied for their effect on marinade uptake. The marinade was used in the ratio of 1.2:10 spices to meat, respectively. Fresh samples were weighted, vacuum packed, and stored at 4–7 0C, whereas frozen samples were stored at -20 0C for 24 hours prior to marination and thawed at room temperature. After marination, percentage uptake, retention, and cooking loss of the marinade were calculated. It was concluded from the yield of marinated products that about 80% of marination takes place in the first 10 minutes of the process. After 10–20 minutes, there was no significant difference (p&gt;0.05), and only 1–2% of the marinade was consumed. The frozen samples show significantly (p≤ 0.05) higher yields and marinade uptake. After marination, the samples were stored at 0–4 0C and fried in vegetable oil until the center reached 70 0C. Cooking loss for this process was non-significant for both varieties of fish as it depends on the water-holding capacity of the meat, which remains the same for both cases. The use of vacuum marination reduced the marination time significantly from 4-6 hours to 10 minutes, and marinade uptake was improved. This process can be used as an alternative to traditional marination techniques.

Deciphering evolutionary dynamics of WRKY genes in Arachis species

BackgroundCultivated peanut (Arachis hypogaea), a progeny of the cross between A. duranensis and A. ipaensis, is an important oil and protein crop from South America. To date, at least six Arachis genomes have been sequenced. WRKY transcription factors (TFs) play crucial roles in plant growth, development, and response to abiotic and biotic stresses. WRKY TFs have been identified in A. duranensis, A. ipaensis, and A. hypogaea cv. Tifrunner; however, variations in their number and evolutionary patterns across various Arachis spp. remain unclear.ResultsWRKY TFs were identified and compared across different Arachis species, including A. duranensis, A. ipaensis, A. monticola, A. hypogaea cultivars (cv.) Fuhuasheng, A. hypogaea cv. Shitouqi, and A. hypogaea cv. Tifrunner. The results showed that the WRKY TFs underwent dynamic equilibrium between diploid and tetraploid peanut species, characterized by the loss of old WRKY TFs and retention of the new ones. Notably, cultivated peanuts inherited more conserved WRKY orthologs from wild tetraploid peanuts than their wild diploid donors. Analysis of the W-box elements and protein–protein interactions revealed that different domestication processes affected WRKY evolution across cultivated peanut varieties. WRKY TFs of A. hypogaea cv. Fuhuasheng and Shitouqi exhibited a similar domestication process, while those of cv. Tifrunner of the same species underwent a different domestication process based on protein–protein interaction analysis.ConclusionsThis study provides new insights into the evolution of WRKY TFs in Arachis spp.

Role of Rap1 GTPases in Growth, Differentiation, and Migration of Myeloid Cells

Background:Rap1 is a Ras-like small-molecular-weight GTP-binding protein involved in signal transduction cascades. It cycles between a GDP-bound inactive and a GTP-bound active form. This switching is regulated by specific GEFs and GAPs. Rap1 exists in two isoforms - Rap1a and Rap1b. While Rap1 has been implicated in regulating several hematologic disorders, including chronic lymphocytic leukemia, its role in the development and function of hematopoietic stem cells and progenitors (HSC/Ps) has not been investigated. Macrophages play an essential role in the retention of hematopoietic cells in the mesenchymal niche. Resident macrophages in the spleen retain HSCs through VCAM1 adhesion. Previous studies have shown that loss of both isoforms of Rap1 in mice results in enhanced peripheral blood leukocyte counts and mobilization of primitive hematopoietic stem cells (Lin-KIT+Sca1+) into peripheral blood circulation. Given this loss of retention of primitive hematopoietic cells in the bone marrow, we hypothesized that perhaps Rap1 plays an essential role in adhesive interactions of HSC/Ps in the bone marrow.&#x0D; Methods:To test this hypothesis, we derived macrophages from the bone marrow of wild-type (WT) and Rap1a/b double knockout (DKO) mice and compared their growth, survival and differentiation using proliferation and adhesion assays, as well as flow cytometry to assess apoptosis, macrophage differentiation, MCSF receptor expression, and expression of integrins.&#x0D; Results:Our studies show that macrophages derived from Rap1 DKO mouse bone marrow show impaired growth, survival and differentiation along with impaired adhesion in response to extracellular matrix components including fibronectin.&#x0D; Future Directions:In the future, we hope to study macrophage adhesive interactions in response to SDF1, collagen, and other extracellular matrix proteins in myeloid-specific deletion of Rap1 in mice, and to study the role of Rap1 in different lineages of hematopoietic cells using different CRE drivers.

Implant–Prosthetic Rehabilitation of Maxillary Lateral Incisor Agenesis with Narrow Diameter Implants and Metal–Ceramic vs. All-Ceramic Single Crowns: A 16-Year Prospective Clinical Study

The main objectives of the present prospective clinical study were to evaluate the marginal bone resorption and the peri-implant soft tissue conditions around narrow diameter implants, as well as the clinical performances of metal–ceramic and all-ceramic single crowns in the implant–prosthetic treatment of maxillary lateral incisors agenesis. Seventy-two patients affected by monolateral or bilateral agenesis of the maxillary lateral incisors were included in the study, and a total of 105 narrow diameter implants were inserted. The final single crowns were fabricated 4 months after the surgical procedures by means of either titanium abutments with Auro-Galvan Crowns (AGC) veneered with feldspathic ceramics or zirconia abutments with all-ceramic (alumina or zirconia) crowns layered with dedicated veneering ceramics. Both marginal bone resorption and soft tissue quality were evaluated after a maximum period of 16 years. Two independent survival curves for patients wearing AGC or all-ceramic crowns were calculated by means of Kaplan–Meier analysis, and a log-rank test was performed in order to compare these curves (p &lt; 0.05). After 16 years of clinical function, a mean marginal bone resorption of 1.2 ± 0.61 mm and good response of peri-implant soft tissues were observed. Descriptive statistics resulted in 80% and 87.1% cumulative success rates for patients provided with AGC prostheses onto titanium abutments and all-ceramic crowns on-to zirconia abutments, respectively. The cumulative survival rate calculated for AGC group was 93.3%, whereas all-ceramic group showed a cumulative survival rate of 95.7%. No statistically significant differences were found with the log-rank tests. The overall success and survival rates calculated were 85% and 95% for all the restorations, respectively. Mucositis, abutment unscrewing, loss of retention, chipping, core fracture, and esthetic failure were the major complications reported. The implant–prosthetic approach can be considered an effective and viable solution to treat cases of maxillary lateral incisor agenesis in the long term.

Addition of Phosphogypsum to Fire-Resistant Plaster Panels: A Physic–Mechanical Investigation

Gypsum (GPS) has great potential for structural fire protection and is increasingly used in construction due to its high-water retention and purity. However, many researchers aim to improve its physical and mechanical properties by adding other organic or inorganic materials such as fibers, recycled GPS, and waste residues. This study used a novel method to add non-natural GPS from factory waste (phosphogypsum (PG)) as a secondary material for GPS. This paper proposes to mix these two materials to properly study the effect of PG on the physico-mechanical properties and fire performance of two Tunisian GPSs (GPS1 and GPS2). PG initially replaced GPS at 10, 20, 30, 40, and 50% weight percentage (mixing plan A). The PGs were then washed with distilled water several times. Two more mixing plans were run when the pH of the PG was equal to 2.4 (mixing plan B), and the pH was equal to 5 (mixing plan C). Finally, a comparative study was conducted on the compressive strength, flexural strength, density, water retention, and mass loss levels after 90 days of drying, before/after incineration of samples at 15, 30, 45, and 60 min. The results show that the mixture of GPS1 and 30% PG (mixing plan B) obtained the highest compressive strength (41.31%) and flexural strength (35.03%) compared to the reference sample. The addition of 10% PG to GPS1 (mixing plan A) improved fire resistance (33.33%) and the mass loss (17.10%) of the samples exposed to flame for 60 min compared to GPS2. Therefore, PG can be considered an excellent insulating material, which can increase physico-mechanical properties and fire resistance time of plaster under certain conditions.

The effect of ball versus locator attachment system on the performance of implant supported overdenture: A systematic review.

This systematic review was aimed to compare ball and locator attachment system on the basis of clinical and biomechanical performance of implant supported overdenture as well as biological and patient related outcomes. Open and free electronic and manual searches were performed in digital databases including MEDLINE via PubMed, the Cochrane Database of Clinical Trials, and Scopus along with some other reliable sources. From the 667 retrieved records, 11 full-text controlled trials were included in this study. Risk of bias was assessed according to RoB 2.0 except for one RCT (economic evaluation), only assessed by CASP checklist. From the 11 retrieved studies, total 183 locator and 219 ball attachments were identified in 452 subjects of 30yrs-95yrs of age. Studies provided data about prosthodontic complications or maintenance (replacement or the activation of matrix and patrix part, loss of retention, fracture and relining of the prosthesis, fracture of the attachment and the survival probability), oral health impact profile, soft tissue parameters and periodontal complications, marginal bone loss, patient related outcome and cost of the attachment systems. Only 5 studies were assessed at low risk bias, while other 6at moderate to high risk of bias. Locator attachment system show lesser complications including loss of retention and lower maintenance appointments, lesser soft tissue, and periodontal complications than the ball attachment. Ball is better in terms of cost effectiveness. In other related outcomes, no significant differences were noted between ball and locator attachment.