Annual Failure Rate Research Articles

Long-Term Success and Survival of Post-Endodontic Restorations Without Posts After up to18 Years: A Practice-Based Study.

The aim of this non-interventional, multi-center, prospective, practice-based study was, firstly, to evaluate the longevity of composite build-ups in endodontically treated teeth, treated with root canal therapy (ETT), without post placement and secondly, to identify and analyze factors influencing the success of these reconstructions. Each of seven general dental practitioners placed up to 50 composite build-ups without additional posts in ETT. Teeth were restricted to incisors, canines and premolars. Clinical data (i.e. type of build-up restoration (material, adhesive); type of final restoration (material, adhesive)) were recorded for 192 coronal restorations on ETT in 192 patients. Cox proportional hazards models were applied to analyze associations between clinical factors and time until failure. Within a follow-up period of up to 18 years (mean(95%CI): 102 (90-113) months, max:217 months) 155 restorations (81%) were judged as successful [mean success time: 176 (165-187) months] and 164 teeth (85%) survived [mean survival time: 187 (178-197) months]. The main failure type was fracture of the restoration (n=16). The annual failure rate was 2.4% and 1.7%, respectively. In bivariate Cox regression the factors 'dentist' and 'adhesive' were significantly associated with failure rate (p≤0.017). However, in multivariate Cox proportional hazards regression none of the investigated factors were significantly associated with failure rate (p≥0.089). For composite build-ups in ETT without post placement high success rates could be found after up to 18 years of observation. Within the limitations of the present study none of the analyzed factors such as 'dentist' or 'adhesive was a significant predictor for the failure rate. Endodontically treated teeth, treated with root canal therapy, can be successfully directly restored with composite build-ups even when no additional post is inserted. The study was registered in the German Clinical Trials Register (DRKS-ID: DRKS00012882).

Adhesive restorations in primary dentition: A retrospective analysis of survival rate and associated factors.

Several clinical and individual factors may play a role in the survival rate of dental restorations, such as characteristics related to the child's age and oral hygiene, and factors associated with the tooth, such as the type of material and number of surfaces to be restored. To analyse the survival rate of adhesive restorations on primary teeth and factors associated with restoration survival. The study included dental records of children aged 3-12 years having received adhesive restorations on primary teeth at a Brazilian dental school between 2009 and 2019. A Kaplan-Meier survival curve was used to plot survival rates using the log-rank test. A multivariate Cox regression model was run to identify individual and dental factors associated with restoration failure. The sample comprised 269 restored teeth in 111 children. Survival curves were similar for all materials (p = .20) and types of isolation (p = .05). The annual failure rate was 3.60% for glass ionomer cement, 1.23% for resin-modified glass ionomer cement and 0.40% for composite resin. The following variables were associated with more failures: Class II restoration compared with Class I (HR = 1.96; 95%CI: 1.28-2.99, p < .001), proportion of decayed teeth (HR = 11.89; 95%CI: 2.80-50.57, p < .001) and child's age (HR = 1.17; 95%CI: 1.06-1.29, p < .001). The different materials and types of isolation had similar survival rates. Children with more decayed teeth have an increased risk of restoration failure.

Clinical Outcomes of Bulk-Fill Resin Composite Restorations: A 10-Year Mapping Review and Evidence Gap Map.

To map the evidence regarding the clinical performance of posterior restorations with bulk-fill resin composites and identify research gaps. This mapping review was conducted following PRISMA-ScR guidelines for scoping reviews, and its protocol was registered on the Open Science Framework platform. Systematic searches were conducted, considering studies published between 2013 and February 2024 in the PubMed, Embase, and Cochrane databases. Clinical studies investigating the performance of bulk-fill resin composite restorations in class I and/or class II preparations with increments of 4 to 5 mm were included. A total of 147 articles were identified, and based on the eligibility criteria, 26 studies were selected for descriptive analysis. Of the reviewed studies, 73% (n = 19) investigated high-viscosity bulk-fill composites, while 30% (n = 8) focused on low-viscosity bulk-fill composites. Evaluation periods ranged from 1 week to 10 years. Reported annual failure rates varied from 0% to 3%, with survival rates between 78.9% and 100%. Bulk-fill resin composites of high viscosity were the most analyzed in the published studies, with evaluation periods of up to 10 years. The review of available scientific evidence showed clinically acceptable performance for composite bulk-fill restorations, with high survival rates and minimal annual failure rates. There is a need for long-term clinical studies on bulk-fill resin composites. This review demonstrates that both high and low-viscosity bulk-fill resin composites exhibit satisfactory clinical performance, which can help clinicians optimize chairside time. However, it is important to highlight the need for further studies with longer follow-up periods.

Longevity and risk factors of CAD-CAM manufactured implant-supported all-ceramic crowns - A prospective, multi-center, practice-based cohort study

ObjectivesThe aim of this prospective, multi-center, practice-based cohort study was to analyze factors associated with the success of implant supported all-ceramic single-unit crowns, made by computer-aided-design/computer-aided-manufacturing (CAD-CAM). MethodsAll-ceramic crowns placed in a private practice-based research network (Ceramic Success Analysis, AG Keramik) were analyzed. Data from 567patients with CAD-CAM implant supported all-ceramic crowns placed between 2008–2023 by 54dentists were evaluated. Firstly, all crowns with at least one follow-up control were included (n = 907). Secondly, all crowns being followed up for ≥ 5years and all failures were included (n = 151). At the latest follow-up visit, crowns were considered as successful (not failed) if they were still in function without the need for additional therapy. Multi-level Cox proportional hazards models were used to evaluate the association between a range of predictors and time of success. ResultsWithin a mean follow-up period (SD) of 2.5 (2)years (first scenario) and 6.2 (1.2)years (second scenario) [maximum:12years], 27crowns failed (annual failure rate [AFR]:0.74 %). The main failure types were decementation, (n = 11), fracture of the ceramic (n = 4) or Ti-Base (n = 4). In 5-year-scenario, crowns fabricated in the laboratory had 26times lower failure rate than those fabricated chairside (95 %CI:0.0–0.7;p = 0.038). Furthermore, the use of a silane (HR:0.051;95 %CI:0.0–0.5;p = 0.014) and etching of the ceramic (HR:0.053;95 %CI:0.0–0.8;p = 0.035) resulted in a significantly higher risk for failure than their non-use. SignificanceFor CAD-CAM manufactured implant supported all-ceramic crowns, high success rates were found in up to 12-year evaluation. Furthermore, after 5years, no patient-or implant-level factors, but operative-level factor (i.e.fabrication method, use of silane/etching) were significantly associated with failure.The study was registered in the German Clinical Trials Register (DRKS-ID: DRKS00020271).

Four-year Outcomes of Class III and IV Anterior Restorations Based on a Subset of German Health Insurance Data.

Numerous studies report on the outcome performance of posterior composite restorations. However, there are fewer studies providing data for anterior restorations. The aim of this study was to evaluate the clinical outcome performance of anterior permanent restorations by analyzing a large dataset from a German national health insurance company. Routine claims data from a major German national health insurance company were assessed. Fee codes were used for tracing restoration careers on a day-count basis. The treatment was defined as a placed restoration (Class III and IV) on a mesial or distal tooth surface, irrespective of the extension. The restorations were placed between January 1, 2010 and December 31, 2013. Statistical analyses were conducted using Kaplan-Meier survival analysis to determine cumulative 4-year survival rates. The primary outcome was re-intervention on the same surface. Secondary outcomes were crowning and extraction which were analyzed separately. A total of 2,417,791 restorations involving mesial surfaces and a number of 2,409,031 restorations involving distal surfaces were observed. At 4 years, the cumulative survival rates concerning the primary outcome 're-intervention' were 79.9% for mesial and 80.9% for distal restorations. The respective annual failure rates (AFR) were 5.5% and 5.2%. Four-year survival rates for the secondary outcome 'crown' were 93.8% for mesial and 94.1% for distal anterior restorations. The respective AFRs were 1.6% and 1.5%. For the secondary outcome 'extraction,' the respective rates were 94.6% for mesial and 93.9% for distal restorations. The respective AFRs were 1.4% and 1.6%. The performance of permanent anterior restorations which were placed in general dental practices in Germany can be rated as acceptable.

MISPLACED COPPER T: A COMPREHENSIVE OVERVIEW

Worldwide, the second most popular form of birth control is Cu T because it is a long term, reversible, highly effective and cost effective contraceptive. In an international study sponsored by the WHO, the average annual failure rate of Copper T was 0.4% or less. Uterine perforation is one of the most dreaded complications of Copper T insertion. The frequency of this occurrence is estimated to be between 0.05 and 13 per 1000 insertions (average, 1.2/1000) and appears to depend on the type of device placed, the skill of the operator, position of the uterus, and intensity of follow-up. A detailed study of case was done who were admitted in our hospital. Further imaging was done and patient were diagnosed with misplaced IUD. The misplaced IUD was removed under vision with hysteroscopy or laproscopy. Minimally invasive techniques like hysteroscopy and advanced laparoscopy are ideally suited to the diagnosis and surgical management of the perforated IUD.

Reliability-based ductility reduction factors surfaces using the generalized bojorquez ground motion intensity measure IBg

In this work, reliability-based ductility reduction factors surfaces are obtained through uniform annual failure rate (UAFR) spectra. For this aim, several nonlinear single degree of freedom (SDOF) systems that include various hysteretic behavior models, constant ductility performance and structural reliability levels are subjected to two sets of ground motions recorded on Mexico City. The first set includes 50 ground motion records located on stiff soils, while the second set correspond to 50 soft soil ground motions. In order to compute the UAFR spectra, the ground motion records were scaled at different values of a particular case of the generalized intensity measure IBg named INp for spectral acceleration. The study discusses the influence of different post-yielding stiffness on UAFR spectra obtained for the selected Bojorquez intensity measure, through the bilinear hysteretic model. Additionally, the Takeda model is used to represent structures that exhibit the effect of stiffness degradation. This study is aimed to compute the effect to obtain ductility reduction factors for various uniform annual failure rates, different degrees of post-yielding stiffness, and different ductility capacity for various nonlinear structures. The analyses of the results indicate that strength reduction (through ductility reduction factors) is mainly influenced by parameters such as ductility, failure rate, period of the system and soil conditions. Finally, reliability-based ductility reduction factor surfaces for stiff and soft soil are provided for different UAFR. It is important to say that this is the first time that ductility reduction factors are proposed based on IBg or INp as intensity measure.

Research on failure rate evaluation test method of energy meter in charging pile

Abstract To verify the failure rate of intelligent energy meter in charging pile and whether it can meet the reliability requirements in “general technical specification for single-phase intelligent electric energy meter (2020)”. Take 20 smart meter samples from four manufacturers, use the accelerated life model and carry out the accelerated test in the way of stress acceleration for a total of 4000 hours, and evaluate the failure rate indicators under normal working stress. The test results show that the single-phase intelligent watt hour meters produced by the four manufacturers can meet the reliability requirements such as annual failure rate index. The accelerated test theory is applied to the reliability life and failure rate evaluation of intelligent electric energy meter to shorten the test time, improve the test efficiency and reduce the test cost.

Over 14-year survival of pressed e.max lithium disilicate glass-ceramic complete and partial coverage restorations in patients with severe wear: A prospective clinical study

Statement of problemLong-term clinical data are lacking on the comparative survival of adhesively luted lithium disilicate glass-ceramic complete and partial coverage restorations in patients with severe wear and the effect that different clinical variables have on their survival. PurposeThe purpose of this study was to examine the 14-year survival of pressed e.max lithium disilicate glass-ceramic complete and partial coverage restorations in patients with severe wear and to evaluate associated clinical parameters. Material and methodsPatients demonstrating severe wear and requiring single unit defect-specific partial or complete coverage restorations were recruited in a clinical private practice and received lithium disilicate restorations. The effect of various clinical parameters was evaluated using Kaplan-Meier survival curves to account for attrition bias and other causes of failure. The statistical significance of differences between parameters was determined by using the log rank test (α=.05). ResultsA total of 53 participants (24 men and 29 women) requiring 662 lithium disilicate restorations were evaluated. The mean age of the participants at the time of restoration placement was 60 (range 25 to 85 years). Of 662 units, 551 were anterior and posterior complete and 111 were posterior partial coverage restorations. Six failures (bulk fracture or large chip) requiring replacement occurred with the average time to failure of 4.5 (range 2 to 8) years, yielding a crude estimate of annual failure of 0.1% (cumulative monitoring period of 4650 years, overall survival rate of 98.6%). Of the 551 complete coverage restorations, 4 failed (0 anterior, 4 posterior), yielding a crude estimate of 0.1% annual failure with the survival function time at 14 years. Of the 111 partial coverage restorations, 2 failed, yielding a crude estimate of 0.4% annual failure with the survival function time at 12 years. The only statistically significant difference was seen between anterior crowns and posterior onlays, with no failures in anterior crowns (P<.001). Other clinical variables had no significant effect on survival (P>.05). ConclusionsPressed e.max lithium disilicate partial and complete coverage restorations both showed high survival rates in patients with severe wear over 14 years with an overall yearly failure rate of 0.1%. Risk of failure at any age was minimal for both men and women. All anterior crowns survived. The highest annual failure rate (0.4%) was for posterior onlay partial coverage restorations.

Remarkably high and accelerating failure rate of a widely used implantable cardioverter-defibrillator lead: A large-scale manufacturer-independent multicenter study with long accurate follow-up

A high annual failure rate of the Linox family defibrillator lead was reported in various small single-center studies. No independent multicenter long-term performance information exists for this lead. Our aim was to assess the longevity of the Linox family leads and to evaluate clinical variables and adverse events associated with failure. This 4-center study included adults >18 years of age who received Linox family leads for the prevention of sudden cardiac death. From November 2006 to November 2016, a total of 3993 high-voltage leads of the Linox family were implanted and followed up on. The absolute failure rate was 10.6% (dwell time to lead failure of 6.3 ± 3.4 years). Multivariate analysis confirmed younger age (for every 5 years younger than 65 years) (hazard ratio 1.09, 95% confidence interval 1.05-1.14, P < .001) and subclavian access (hazard ratio 1.46, 95% confidence interval 1.18-1.81, P < .001) as independent risk factors for lead failure. Patients frequently presented themselves with inappropriate shocks (20% in patients with lead failure) due to detection of nonphysiologic high-rate signals/noise. This is the largest physician-driven multicenter study on the very long-term performance of Linox family leads. Our data report a remarkably high failure rate of these leads. Our findings have significant implications for the management of patients. Monitoring by remote care should be available for all active Linox family leads.

Bond strength and marginal adaptation of resin composites and correlations with clinical results

ObjectivesDue to innumerable confounding factors and a high number of types and brands of dental restorative materials, the clinical performance of restorative materials are sought predicted by various in vitro tests. However, only few such tests have been found to correlate well with clinical findings. Thus, the present study determined the in vitro dentin bond strength and marginal adaptation of Class II restorations and correlated the results to their clinical outcomes. MethodsDentin bond strength (µTBS and µSBS) and marginal gap formation of Class II restorations (replica technique and SEM) were measured after 24 h and 6 m water storage using eight combinations of adhesive and resin composite. Clinical outcomes (mean survival time, Hazard Ratio, annual failure rate; n = 10.695) were gained from a data set of a retrospective multicenter study of direct restorations. ResultsSignificant differences were found for dentin bond strength and marginal gap formation between the restorative material groups, and negative effects of long-term storage were observed. µTBS correlated significantly with certain clinical outcomes of Class I restorations, while µSBS correlated with certain clinical outcomes of Class II, III, IV and V restorations. Marginal gap formation in enamel and number of paramarginal fractures correlated with certain clinical outcomes of Class II restorations. SignificanceUsing the same restorative materials in vitro as in vivo, gave significant, but weak correlations between in vitro bond strength or marginal adaptation and clinical outcomes, lending support to the use of in vitro tests in early stages of material selection.

Influence of Cavity Lining on the 3-Year Clinical Outcome of Posterior Composite Restorations: A Randomized Controlled Clinical Trial.

The purpose of this randomized, split-mouth-designed controlled and single-blinded clinical study was to evaluate the 3-year clinical performance of Class I and Class II resin composite restorations placed with or without cavity lining with a flowable composite. Fifty patients with treatment needs in two premolars or molars were included. One of the teeth was restored using the nanohybrid composite (Grandio®SO, control group), in the test group a high viscosity flowable composite was additionally applied as a first layer. In both groups, the same self-etch adhesive system was applied. Clinical evaluation after 3 years was carried out using the modified USPHS/Ryge criteria. At the 3-year follow-up the recall rate was 92%. Four restorations failed in the test group (8.7%), three due to the loss of vitality and one after fracture. The control group exhibited a cumulative success rate of 100%, while the test group achieved a success rate of 91.3%. This led to significant differences in the annual failure rate (AFR) between the two groups, with rates of 0% and 2.9% (p < 0.05; Mann-Whitney U-test). After 3 years the cumulative survival rate including all restorations was 95.7%. Statistical analysis revealed significant differences for the parameters: tooth vitality, marginal discoloration, success rate, and AFR. The other parameters exhibited no significant differences. Consequently, the nanohybrid composite demonstrated excellent performance over a 3-year period, whereas the utilization of a flowable composite for the cavity lining did not appear to exert a beneficial influence on clinical outcomes.

Long-term performance of ceramic in/-onlays vs. cast gold partial crowns – a retrospective clinical study

ObjectivesTo assess the long-term clinical performance of ceramic in-/onlays (CIOs) and cast gold partial crowns (CGPCs) in posterior teeth in terms of success, survival, complications (biological, technical) and quality.Material and methodsIn a retrospective study, a total of 325 patients were recorded after up to 24.8 years (mean 13.9 ± 3.8 years) having (pre-)molars restored with CIO (Empress I, Ivoclar Vivadent, n = 161) and CGPC (Degunorm, DeguDent, n = 164) by supervised undergraduate students. A total of 296 restorations were assessed clinically and radiologically in healthy and endodontically treated teeth using modified United States Public Health Service (USPHS) criteria. Cumulative success and survival rates of the restorations were calculated using Kaplan–Meier estimates. Biological and technical complications were recorded. Status of oral health comprising caries risk and localized periodontitis were assessed.ResultsThe cumulative success rates of CIOs were 92.1% and of CGPCs 84.2% after mean service times of 14.5 years. The annual failure rates of total service times were 0.5% in teeth restored with CIO (n = 155) and 0.7% in teeth restored with CGPC (n = 163). The cumulative survival rates of CIOs were 93.9% after a mean service time of 15.2 years and decreased to 91.7% after 23.5 years. The cumulative survival rates of CGPCs were 92.6% after a mean service time of 14.9 years and 91.8% after 23.5 years. Complications in CIOs (n = 149) were ceramic fracture (6.7%), secondary caries (4.7%), endodontic complication (2.7%) and tooth fracture (1.3%) compared to CGPCs (n = 147) with endodontic complication (8.8%), secondary caries (4.8%) and decementation (2.0%). Endodontically treated teeth restored with CIO or CGPC revealed significantly less often success compared with corresponding vital teeth (p = .02). CIOs and CGPCs revealed clinically and radiographically good and excellent qualities with 71.8% (107/149) and 68% (100/147) without any significant differences regarding type of restoration.ConclusionsBoth CIOs and CGPCs achieved high survival rates up to 24.8 years when performed by supervised undergraduate students. The longevity of the restorations may benefit from the intraoral repair of accessible defects and, in case of pulp infection or necrosis, an adequate endodontic management.Clinical relevanceCIOs and CGPCs made by supervised undergraduate students are proper restoration types in posterior teeth in the long-term. An adequate preparation design, meticulous care in the inserting technique and constant biofilm removal due to proper oral hygiene combined with professional maintenance care are substantial. The clinical long-term performance was mostly limited by ceramic fractures in CIOs and endodontic complications in CGPCs.

Clinical evaluation of Giomer and self-etch adhesive compared with nanofilled resin composite and etch-and-rinse adhesive – Results at 8 years

ObjectiveThis study aimed to evaluate the long-term clinical performance of Giomer and a self-etch adhesive system compared with a nanofilled resin composite and etch-and-rinse adhesive system in Class I and Class II restorations. MethodThe study was designed to be double-blinded with intra-individual control. 48 patients with 54 pairs of cavities (class I or class II) were recruited. Each pair of restorations was placed with either BEAUTIFIL II (BF) and FL-BOND II (FL) or Filtek Z350 (Z350) and Scotchbond Multi-Purpose (SMP). Clinical evaluation was performed at baseline, 6-month, 18-month, 4-year and 8-year after placement according to modified USPHS criteria. Kaplan-Meier survival analysis and log rank tests were performed (SPSS 20.0, IBM Corporation, US) to compare the survival probability of different restorations.A generalized linear mixed model (GLMM) was adopted to assess the performance of the materials. The McNemar test was used to show significant changes for all the evaluation criteria and difference between them. ResultsAt the eight-year recall, 32 patients with 67 restorations were present. There were twelve restorations in total recorded as failure due to loss of retention, restoration fracture, secondary caries, tooth fracture or endodontic treatment due to pulp necrosis. The survival probabilities and calculated annual failure rate(AFR) of BF and Z350 restorations at 8-year were 87.2 % vs 87.8 % and 1.6 % vs 1.5 % respectively with no significant difference (p > 0.05)between the two materials. Over the recall time range of eight years, decreased possibility of alpha rating was observed for retention, marginal adaptation, marginal staining and surface roughness for both materials (p < 0.05). Decreased possibility of alpha rating was observed for surface staining and secondary caries for Z350 (p < 0.05) and restoration fracture for BF (p < 0.05), respectively. Comparing the two restorative systems over eight years, no significant difference was seen for linear decline of the possibility of alpha rating for any of the criteria evaluated (p > 0.05). ConclusionGiomer material and the self-etch adhesive system had comparable clinical performance with nanofilled resin composite and etch-and-rinse adhesive system over the observation period of eight years.

Longevity of composite restorations in posterior teeth placed by dental students: a 12-year retrospective study.

To evaluate the longevity of resin composite restorations placed in posterior teeth by dental students, using data from electronic records from 2008 to 2019. Demographic (gender and age) and clinical variables (dental group, position in dental arch, and the number of restored surfaces) were evaluated. The 5-year follow-up was assessed according to the day the restoration was placed. Kaplan-Meier curves were generated to calculate the annual failure rate. Data were analyzed by Chi-Square, Kruskal-Wallis, and Mann-Whitney tests (α = 0.05). In total, 3.883 records relative to return periodicity were analyzed. The final sample consisted of 900 restorations from 479 patients. The majority were females, aged between 31 and 60. In total, 256 failures were reported (success rate = 78%), showing an annual failure rate of 2.05%. The main reasons for failures were restoration replacement (55.5%), endodontics (21.9%), prosthetics (14.5%) and extraction (8.2%). There was a higher risk of failure in restorations involving three or more surfaces (p = 0.000) and in patients over 60 years (p < 0.001). In females (p = 0.030), molars (p = 0.044), and maxillary teeth (p = 0.038) failed in a shorter time. Resin composite restorations placed in permanent posterior teeth by dental students had high survival rates. The main reason for failure was the replacement of restorations. The age group and the number of restored surfaces significantly affected the success of the restorations. The electronic health records over 12 years showed that 78% of the resin restorations in posterior teeth placed by dental students were successful for a minimum of five years.

40-Year Outcome of Old-School, Non-Surgical Endodontic Treatment: Practice-Based Retrospective Evaluation.

(1) Background: Non-surgical endodontic treatment has been shown to be clinically successful; however, clinical long-term data are scarce. This practice-based retrospective clinical investigation evaluated endodontic outcomes over 40 years and identified relevant clinical co-factors. (2) Methods: Two experienced dental practitioners in two different private dental practices treated 174 patients with 245 teeth from 1969 to 1993. After root canal obturation, either a new direct restoration (amalgam, resin composite, or glass-ionomer cement) or the re-cementation of a pre-existing prosthetic restoration or renewal of prosthetic restoration followed. Metal posts (operator A) or metal screws (operator B) were inserted when coronal substance loss was significant. The primary outcome (i.e., tooth survival) was achieved when the endodontically treated tooth was, in situ, painless and had full function at the end of the observation period. A secondary outcome, the impact of different prognostic factors on survival rate, was evaluated. (3) Results: The overall mean survival was 56.1% of all treated teeth after 40 years of clinical service, resulting in an annual failure rate of 1.1%. Most investigated clinical co-factors (jaw, tooth position, intracanal dressings, post/screw placement, and gender) showed no significant influence on survival. (4) Conclusions: Even with materials and techniques from the 1970s and 1980s, successful root canal treatment was achievable. Except for post-endodontic restorations, most of the evaluated factors had no significant influence on the clinical long-term survival of root canal-treated teeth.

Metamodeling-based reliability analysis framework for activated sludge processes

The reliability of activated sludge processes will be adversely affected by alterations in wastewater production and pollutant loading foreseen due to population growth, urbanization, and climate change, as well as the tendency to amend environmental regulations to mandate stricter effluent quality standards to alleviate water pollution. Until now, there was no framework capable of effectively managing these multifaceted challenges in reliability analysis. Previous attempts conducted a low number of simulations leading to insufficient statistical significance to properly validate reliability quantification. A metamodeling-based reliability analysis framework for the activated sludge process is introduced to cope with alterations in wastewater production and pollutant loading, assesses the reliability under different effluent regulations, and leverages metamodels to conduct extensive simulation work, to estimate the reliability. All metamodels produced high-resolution results, enabling reliability estimation after 100 000 simulations. The framework effectively assessed the annual failure rates of various activated sludge facility designs under four regulations, demonstrating the impact of stricter effluent quality standards. Integrating metamodels for reliability analysis greatly lowers computational costs, making the framework a time and resource-efficient choice for quick decision-making in facility design.

A Retrospective Clinical Evaluation of Esthetic Restorations: Class III, IV, And V

This study aimed to evaluate direct composite restorations Class III, IV and V through the USPHS and FDI criteria. Eighty-seven patients were selected through a search of the patients’ records present in the School of Dentistry. Restorations performed between 2000 to 2013 which a minimum of six months in service were selected. Adult patients of both sexes were included, who received composite restorations with total-etch adhesive system; on vital and non-vital teeth. Clinical evaluation was performed by USPHS and FDI criteria, by one calibrated examiner. The survival of the restorations was analyzed using the Kaplan-Meier and log-rank test to compare groups, and multivariate Cox regression and hazard ratio were employed to identify factors associated with the failure of the restorations. 272 restorations were evaluated with a time interval in service from 8 months to 13 years (mean 4.8 years). 120 class III restorations were evaluated with 15 failures (12.5%), with an annual failure rate of 2.74%. For class IV, 80 restorations were evaluated, with 38 failures (47.5%), with an annual failure rate of 12.6%. And for class V, 72 restorations were analyzed, with the presence of failures in 27 of them (37.5%), with annual failure rate of 9.3%. The most common reason for failure was fracture and loss of retention, occurring in 73 cases in total. Non-vital teeth showed 50% of failure, with an annual failure rate of 13.4%; while the vital teeth showed 28.1% of failure, with an annual failure rate of 6.6%. It was concluded that composite restorations showed a satisfactory performance over time, with a survival rate of 70.6% in a mean time of 4.8 years. Class III showed better clinical performance than class V and IV. Non-vital teeth restorations had 2.37 times the risk of failures than vital teeth. Both criteria (USPHS and FDI) were effective in the clinical evaluation process.

Clinical performance of a glass-hybrid system in comparison with a resin composite in two-surface class II restorations: a 5-year randomised multi-centre study

ObjectiveTo evaluate the 5-year clinical performance of a glass hybrid restorative system and a nano-hybrid resin composite in moderate to large two-surface class II cavities.Materials and methodsThis study was carried out by dental schools in Zagreb, Croatia; Izmir, Turkey; Belgrade, Serbia; and Milan, Italy. A total of 180 patients requiring two class-II two-surface restorations in the molars of the same jaw were recruited. The teeth were randomly restored with either a nano-hybrid resin composite (Tetric EvoCeram, Ivoclar Vivadent) or a glass-hybrid material (EQUIA Forte, GC). During the 5-year follow-up, two calibrated evaluators at each centre scored the restorations annually using the FDI-2 scoring system. The survival rates were calculated using the Kaplan–Meier method and compared using non-parametric matched pair tests (p < 0.05).ResultsThere were no statistically significant differences between the overall survival and success rates of the two types of restorations (p>0.05). The success rates (FDI-2 scores 1–3) for EQUIA Forte were 81.9% (average annual failure rate: 3.9%) and 90.7% for Tetric EvoCeram (average annual failure rate: 1.9%). The survival rates (FDI-2 scores 1–4) for EQUIA Forte and Tetric EvoCeram were 94.5% and 94.4%, respectively, with an average annual failure rate of 1.1%.ConclusionsIn terms of success and survival rates, both the glass-hybrid restorative system and the nano-hybrid resin composite have been shown to perform satisfactorily.Clinical relevanceThe results of this study indicate that EQUIA Forte can be one of the therapeutic options for moderate to large two-surface class II restorations of posterior teeth.

Survival analysis of posterior composite restorations in National Dental PBRN general dentistry practices

ObjectiveQuantify the survival of posterior composite restorations (PCR) placed during the study period in permanent teeth in United States (US) general dental community practices and factors predictive of that survival. MethodsA retrospective cohort study was conducted utilizing de-identified electronic dental record (EDR) data of patients who received a PCR in 99 general dentistry practices in the National Dental Practice-Based Research Network (Network). The final analyzed data set included 700,885 PCRs from 200,988 patients. Descriptive statistics and Kaplan Meier (product limit) estimator were performed to estimate the survival rate (defined as the PCR not receiving any subsequent treatment) after the first PCR was observed in the EDR during the study time. The Cox proportional hazards model was done to account for patient- and tooth-specific covariates. ResultsThe overall median survival time was 13.3 years. The annual failure rates were 4.5–5.8 % for years 1–5; 5.3–5.7 %, 4.9–5.5 %, and 3.3–5.2 % for years 6–10, 11–15, and 16–20, respectively. The failure descriptions recorded for < 7 % failures were mostly caries (54 %) and broken or fractured tooth/restorations (23 %). The following variables significantly predicted PCR survival: number of surfaces that comprised the PCR; having at least one interproximal surface; tooth type; type of prior treatment received on the tooth; Network region; patient age and sex. Based on the magnitude of the multivariable estimates, no single factor predominated. ConclusionsThis study of Network practices geographically distributed across the US observed PCR survival rates and predictive factors comparable to studies done in academic settings and outside the US. Clinical significanceSpecific baseline factors significantly predict the survival of PCRs done in US community dental practices.