Bonferroni Correction Factor Research Articles

Single- and Double-Loaded All-Suture Anchor Repairs of Anteroinferior Labral Tears Are Biomechanically Similar in a Cadaveric Shoulder Model

To compare the biomechanical strength of single- versus double-loaded all-suture constructs in an anteroinferior glenoid labral repair. Anteroinferior labral lesions were created on 6 matched pairs of cadaveric shoulder specimens. Each shoulder in a matched pair was randomized to either receive capsulolabral repair with 3 single-loaded all-suture anchors or 3 double-loaded all-suture anchors. Immediately following capsulolabral repair, the specimens underwent mechanical testing, which included cyclic testing (5 N to 50 N for 500 cycles) and load-to-failure testing (rate of 15 mm/min). The gap formation between the repaired labrum and glenoid (measured at 1, 25, 100, and 500 cycles), the load at 2-mm gap formation, the maximum load at failure and the method of failure were recorded. Data were analyzed with paired Student t tests and Bonferroni correction factor. The single and double all-suture constructs did not differ significantly in gap formation at any number of cycles, load to 2-mm gap formation (P= .75), or maximum load to failure (P= .46) between the 2 groups. In this study, single-loaded and double-loaded all-suture anchor constructs demonstrated comparable biomechanical performance and did not significantly differ in gap formation, load to 2-mm gap formation, or maximum load to failure when used in the capsulolabral repair of anteroinferior glenoid labral tears in human cadaveric specimens. Although studies have evaluated the biomechanical properties of various arthroscopic labral stabilization techniques, the biomechanical properties of all-suture anchors with regard to labral stabilization are not well understood.

TSLP and IL-7R Variants Are Associated with Persistent Atopic Dermatitis

TSLP and IL-7R Variants Are Associated with Persistent Atopic Dermatitis

Body Composition Comparison of Upper- and Underclass Reserve Officers' Training Corps Cadets.

INTRODUCTION: Body composition (BC) measurements are used to determine qualification for enlistment and to ensure active members are meeting standards. Although there is extensive research on BC in active-duty military, very few have examined ROTC cadets. The purpose of this study was to identify and quantify differences in BC between freshman/sophomore [underclass (UND)] and junior/senior [upperclass (UPP)] ROTC cadets by using bioelectrical impedance spectroscopy (BIS).METHODS: UND (N = 21) and UPP (N = 15) Air Force ROTC cadets volunteered for this study. BIS was used to measure fat mass percentage (FM%), fat free mass percentage (FFM%), total body water percentage (TBW%), extracellular fluid percentage (ECF%), and intracellular fluid percentage (ICF%). Separate one-way ANOVAs were run between UND and UPP for all dependent variables with a Bonferroni correction factor. Additionally, a Pearson correlation between abdominal circumference (AC) and FM% was conducted.RESULTS: No significant differences were observed between the UND and UPP groups' BMI. However, significant differences were observed for ECF%, ICF%, TBW%, FFM%, and FM% in which the UPP had a higher TBW%, ICF%, FFM%, and a lower ECF% and FM% compared to the UND.CONCLUSIONS: This study observed significant differences in BC across class ranks in ROTC cadets. Findings from this study suggest that due to an increased exposure to ROTC training, UPP cadets have a more ideal body composition (FFM% and FM%) when compared to UND cadets.Johnson QR, Mackey CS, Muddle TD, Smith DB, DeFreitas JM. Body composition comparison of upper- and underclass Reserve Officers Training Corps cadets. Aerosp Med Hum Perform. 2019; 90(9):813-818.

Pattern of wavefront aberrations in Indian children with ametropia

Purpose: The aim of this study was to evaluate the distribution of wavefront aberrations in Indian children with refractive errors and to determine the correlation between the degree of refractive error and aberration. Materials and Methods: A prospective study was conducted on 216 eyes of 108 consecutive children attending the outpatient clinic. Based on refractive error, the children were allocated to five groups: “Emmetropic,” “hyperopic,” “simple astigmatism,” “compound astigmatism,” and “myopic” group. Lower order aberrations (LOAs) and higher order aberrations (HOAs) were analyzed within and between the groups. Results: Mean age of the children was 10.9 years. Of the total 216 eyes, 40 eyes had emmetropia, 52 had simple astigmatism, 54 had compound astigmatism, 43 had myopia, and 27 had hyperopia. In all the groups, increase in spherical equivalent was associated with increase in LOAs of defocus and astigmatism and the root mean square (RMS) of total HOAs. In comparison with the “emmetropic” group, all other groups showed a significant increase in LOAs (P < 0.001) and RMS of total HOAs (P < 0.001), with the “compound astigmatism” group showing higher values. Spherical aberrations were found to be associated with simple astigmatism, compound astigmatism (P = 0.008), and myopia (P = 0.041). Statistical analysis was done using analysis of variance applying Bonferroni correction factor and Pearson's correlation coefficient. Conclusions: Ametropic eyes are associated with HOAs. Indian children were found to have higher values of aberrations when compared to other races. Practitioners may need to factor this while treating children for refractive errors.

Comparison of confidence intervals for the Behrens-Fisher problem

ABSTRACTThe Behrens–Fisher problem concerns the inferences for the difference between means of two independent normal populations without the assumption of equality of variances. In this article, we compare three approximate confidence intervals and a generalized confidence interval for the Behrens–Fisher problem. We also show how to obtain simultaneous confidence intervals for the three population case (analysis of variance, ANOVA) by the Bonferroni correction factor. We conduct an extensive simulation study to evaluate these methods in respect to their type I error rate, power, expected confidence interval width, and coverage probability. Finally, the considered methods are applied to two real dataset.

Measuring skin to subarachnoid space depth in Egyptian population: A prospective cohort study.

Background:Lumbar puncture is a difficult medical skill and is used for administering subarachnoid anesthetic medications. Estimation of skin to subarachnoid space depth (SSD) helps to reduce post spinal anesthetic complications.Aims:To measure the SDD in overall Egyptian population and to find a formula for predicting SSD in Egyptian patients.Settings and Design:Four hundred patients of American Society of Anesthesiologist class I and II adult Egyptian patients undergoing surgery using spinal anesthesia in general and obstetric surgery unit, Mansoura University main hospital, were included in this prospective, observational study.Subjects and Methods:Patients were divided into three groups: Males (Group M), nonpregnant females (Group F), and pregnant females (Group PF). SSD was measured after performing lumbar puncture. The relationship between SSD and patient characteristics was studied; correlated and statistical analysis was used to find a formula for predicting SSD.Statistical Analysis Used:Statistical analysis was done using Statistical Package for Social Sciences (SPSS 19.0, Chicago, IL, USA). One-way ANOVA with post hoc (Bonferroni correction factor) analysis was applied to compare the three groups. All the covariates in the study further were taken for multivariate analysis. Multivariate regression analysis was performed to evaluate important covariates influencing SSD for each group separately.Results:Mean SSD was 4.99 ± 0.48 cm in the overall population. SSD in adult males (4.93 ± 0.47 cm) was significantly longer than that observed in females (4.22 ± 0.49 cm) but was comparable with SSD in parturient (4.32 ± 0.47 cm). Formula for predicting SSD in the overall population was 2.1+ (0.009 × height) + (0.03 × weight) + (0.02 × body mass index [BMI]) + (0.15 × body surface area [BSA]). Craig's formula when applied correlated best with the observed SSD.Conclusions:SSD in adult males was significantly longer than that in both pregnant and nonpregnant females, but it was nearly the same in pregnant and nonpregnant females. SSD in Egyptian population can be calculated based on height, weight, BMI, and BSA. Craig's formula was the most suitable to be applied to Egyptian population.

Estimation of Skin to Subarachnoid Space Depth: An Observational Study.

In a patient, the skin to Subarachnoid Space Depth (SSD) varies considerably at different levels of the spinal cord. It also varies from patient to patient at the same vertebral level as per age, sex and Body Mass Index (BMI). Estimation of the skin to SSD reduces complications related to spinal anaesthesia. To measure the skin to SSD in the Indian population and to find a formula for predicting this depth. Three hundred adult patients belonging to American Society of Anaesthesiologist class I and II, undergoing surgery using spinal anaesthesia in various surgical specialities of Gauhati Medical College were selected by systemic sampling for this prospective, observational study. Patients were divided into three groups: Group M containing male patients, Group F containing non-pregnant female patients, and Group PF containing pregnant female's patients. SSD was measured after performing lumbar puncture. The relationship between SSD and patient characteristics were studied, correlated and statistical analysis was used to find a formula for predicting the skin to SSD. Statistical analysis was done using Statistical Package for Social Sciences (SPSS 21.0, Chicago, IL, USA). One-way ANOVA with post-hoc(Bonferroni correction factor) analysis was applied to compare the three groups. Multivariate analysis was done for the covariates followed by a multivariate regression analysis to evaluate the covariates influencing SSD for each group separately. Mean SSD was 4.37±0.31cm in the overall population. SSD in adult males was 4.49±0.19cm which was significantly longer than that observed in female's 4.18±0.39cm which was comparable with SSD in parturient 4.43±0.19 cm. The formula for predicting the skin to SSD in the male population was 1.718+0.077×BMI+0.632×Height, in nonpregnant female population was 1.828+0.077×BMI+0.018×Height+0.007×Age and 0.748+0.209×BMI+4.703×Height-0.054×weight in parturient females, respectively. Skin to SSD correlated with the BMI in all the patients in our study.

Auto-antibodies against gangliosides in patients with Charcot-Marie-Tooth disease

Background: In Charcot-Marie Tooth (CMT), vital components of either the myelin sheath or axon are abnormal, slowing nerve conduction and causing functional disability. Recently, there has been speculation the CMT may have an autoimmune component resulting from abnormal protein expression. Methods: Custom autoimmune neuropathy-focused microarray panels were printed in-house using antigens from Sigma, Abnova, Fitzgerald and Matreya according to Cambridge Life Science instructions. Antigens including Myelin Protein Zero, Peripheral Myelin Protein 22, and 20 other well-known gangliosides were tested for IgM and IgG antibodies. Students T-Test and Bonferroni correction factor were used to determine statistical significance between groups and in post-hoc subgroup analysis. Results: Plasma was tested from 17 patients with CMT and 25 young healthy individuals. CMT population consisted of 9 CMT-1a, 1 CMT-1b, 4 CMT-2a, 2 CMT-2f and 2 undetermined CMT type 2 patients. No ganglioside reached statistical significance under a Bonferroni Correction factor (p&gt;0.01) nor were any gangliosides notably raised compared to normal. Sub-group analysis did not reveal theorized peak auto-antibodies levels depending upon their CMT sub-type compared to normal. Conclusions: Although previously shown to have increased auto-antibodies to myelin or axonal proteins, CMT individuals did not demonstrate increased autoantibody levels for the proteins tested at our centre.

Assessment of immune function after short-term administration of recombinant human growth hormone in healthy young males

Growth hormone (GH) is a commonly used drug aimed at improving sport performance. The aim of this study is to evaluate the immunomodulatory effects of short-term administration of recombinant GH (rhGH) in healthy young males. NK cell number, activity and phenotype, T cell number, CD4(+) (Th1/Th2) cytokine production of IL2, IL4, IL6, IL10, TNF-α and IFN-γ and CD4(+)/CD8(+) ratio with particular attention to the possible correlation to IGF-I production were investigated. 30 males (27 ± 9 years) were randomly assigned to placebo (n = 15) or drug (rhGH) 1 mg/day groups (n = 15) with daily injection for 7 days. IGF-I plasma concentration and flow cytometry data were generated at baseline and days 8, 15, 22 and 29 post injection. Data analysis used General Linear Model with repeated measures, Bonferroni correction factor and significance at p ≤ 0.05. Serum IGF-I levels (ng/mL) increased significantly (p ≤ 0.01) on day 8 (0.48 ± 0.78) after injections compared to baseline (0.31 ± 0.07) and days 15 (0.33 ± 0.06), 22 (0.29 ± 0.05) and 29 (0.29 ± 0.06). A significant time effect was noted in IL10 secretion (pg/mL) from day 15 (P = 35.14 ± 19.93, rhGH = 26.63 ± 16.39) to days 22 (P = 61.32 ± 20.41, rhGH = 74.99 ± 46.91) and 29 (P = 101.98 ± 67.25, rhGH = 107.74; ± 122.58). There was no correlation between IGF-I and NK activity, phenotype or number along with T lymphocyte number, CD4(+)/CD8(+) ratio or Th1 and Th2 cytokine production. In conclusion, cytokine secretion spectrum was not affected by short-term rhGH administration in young males.

Recombinant human growth hormone—Effects on cytokine production in healthy young males

Introduction: Growth hormone (GH) has being used for different clinical purposes resulting in improvement of immunological function of patients with impaired immune system. However, there is paucity in the literature examining the potential effects of recombinant human GH (rhGH) on lymphocytes and cytokine production of healthy populations. The aim of the present study was to investigate the effect of short term (7 days) administration of exogenous rhGH on T lymphocytes (CD4; CD8) and cytokine production—IL-2, IL-4, IL-6, IL-10, tumour necrosis factor (TNF)-α and interferon (IFN)-γ on human peripheral blood mononuclear cells (PBMC), and their relation with IGF-I levels in healthy young males. Methodology: 30 young males (25.7 yrs ± 7.80 SD) participated in a 29 days study where either 0.9% sodium chloride or 1 mg of rhGH was administered from day 1 to day 7. The participants were randomly assigned into either placebo (P; n = 15; 26.1 ± 6.6 yrs)) or rhGH 1 mg/day (n = 15; 24.5 ± 6.5 yrs). Baseline (day 0) and post injections samples (days 8, 15, 22 and 29) were analysed for IGF-I, T cells numbers and cytokine production at PBMC. General Linear Model with repeated measures was applied and Bonferroni's correction factor was utilized with p ≤ 0.05 denoting statistical significance. Results: T cells numbers and CD4/CD8 ratio presented no difference however Th2 cytokines increased indicating a shift from Th1 to Th2 from day 15 to days 22 and 29. Specifically, there was a significant difference between groups for IL-10 (Mean Fluorescence Intensity, MFI) at day 15 (P = 35.14; ±19.93 SD, rhGH = 26.63; ±16.39 SD), day 22 (P = 61.32; ±20.41 SD, rhGH = 74.99; ±46.91 SD), day 29 (P = 101.98; ±67.25 SD, rhGH = 107.74; ±122.58 SD). Plasma IGF-I (ng/mL) increased significantly on day 8 (0.48 ± 0.78 SD) after injections compared to baseline (0.31 ± 0.07 SD), day 15 (0.33 ± 0.06 SD), 22 (0.29 ± 0.05 SD) and 29 (0.29 ± 0.06 SD). Conclusion: Although the lymphocyte numbers were not significantly different from baseline to day 29 between groups, cytokine production showed a significant increase over the post administration. It is conclusive that cytokine release can be affected by short-term rhGH administration in healthy young males suggesting that rhGH may act on CD4+T lymphocytes to increase IL-10 production.

Vitamin C Supplementation and Salivary Immune Function Following Exercise-Heat Stress

Prolonged physical exertion and environmental heat stress may elicit postexercise depression of immune cell function, increasing upper respiratory tract infection (URTI) susceptibility. We investigated the effects of acute and short-term vitamin C (VC) compared with placebo (PL) supplementation on URTI susceptibility, salivary immunoglobulin A (s-IgA), and cortisol responses in healthy individuals following prolonged exercise-heat stress. Twelve participants were randomized into the VC or PL group in a double-blind design. For 12 days, participants consumed 3x500 mg tablets of VC or PL per day, with testing completed at baseline, then following acute (1 d) and short-term (8 d) supplementation. Participants performed 120.1+/-49.6 min of cycling at 54+/-6% VO2max in a hot (34.8+/-1.0 degrees C and 13+/-3% relative humidity) environment, with saliva samples collected at pre-, post-, and 72 h postexercise. Health logs specifying URTI symptoms were completed for 7 days postexercise. A 2x3x3 mixed ANOVA with a post hoc Bonferroni correction factor revealed a significant linear trend in postexercise cortisol attenuation in the VC group, 21.7+/-15.1 nmol/L (mean+/-SD) at baseline, to 13.5+/-10.0 at acute, to 7.6+/-4.2 after short term (P=.032). No differences were detected in ratio of s-IgA to protein or URTI symptoms between groups. These data suggest that vitamin C supplementation can decrease postexercise cortisol in individuals performing exercise similar to that of a half-marathon or marathon in hot conditions. However, no changes in s-IgA and URTI were evident, possibly due to previous moderate training and reduced physical and psychological stress compared with athletes participating in ultramarathons.

Analysis of HLA association in susceptibility to infection with Cryptococcus neoformans var. gattii in a Papua New Guinean population

The possible association between susceptibility to infection with Cryptococcus neoformans var. gattii and HLA phenotype was examined in a group of Papua New Guinean patients. There was no evidence for a statistically significant association between susceptibility to infection and HLA class I and HLA class II phenotypes, although analysis of data which had not been subjected to the appropriate Bonferroni correction factor suggested a trend for susceptibility linked to HLA B*5601.

Brain-derived Neurotrophic Factor-Tropomyosin-related Kinase B Signaling Contributes to Activity-dependent Changes in Synaptic Proteins

The ability of synapses to undergo changes in structure and function in response to alterations of neuronal activity is an essential property of neural circuits. One way that this is achieved is through global changes in the molecular composition of the synapse; however, it is not clear how these changes are coupled to the dynamics of neuronal activity. Here we found that, in cultured rat cortical neurons, bidirectional changes of neuronal activity led to corresponding alterations in the expression of brain-derived neurotrophic factor (BDNF) and phosphorylation of its receptor tropomyosin-related kinase B (TrkB), as well as in the level of synaptic proteins. Exogenous BDNF reversed changes in synaptic proteins induced by chronic activity blockade, while inhibiting Trk kinase activity or depleting endogenous BDNF abolished the concentration changes induced by chronic activity elevation. Both tetrodotoxin and bicuculline had significant, but opposite, effects on synaptic protein ubiquitination in a time-dependent manner. Furthermore, exogenous BDNF was sufficient to increase ubiquitination of synaptic proteins, whereas scavenging endogenous BDNF or inhibiting Trk kinase activity prevented the ubiquitination of synaptic proteins induced by chronic elevation of neuronal activity. Inhibiting the proteasome or blocking protein polyubiquitination mimicked the effect of tetrodotoxin on the levels of synaptic proteins and canceled the effects of BDNF. Our study indicates that BDNF-TrkB signaling acts upstream of the ubiquitin proteasome system, linking neuronal activity to protein turnover at the synapse.

The effect of nitrous oxide on halothane, isoflurane and sevoflurane requirements in ventilated dogs undergoing ovariohysterectomy

Objective To examine the effect of 64% nitrous oxide (N2O) on halothane (HAL), isoflurane (ISO) or sevoflurane (SEV) requirements in dogs undergoing ovariohysterectomy.Study design Prospective, randomized, clinical trial.Animals Ninety, healthy dogs of (mean ± SD) body weight 21.2 ± 10.0 kg and age 17.8 ± 22.8 months.Materials and methods After premedication with acepromazine, hydromorphone and glycopyrrolate, anesthesia was induced with thiopental administered to effect. Dogs received one of six inhalant protocols (n = 15 group): HAL; HAL/N2O; ISO; ISO/N2O; SEV; or SEV/N2O. End-tidal CO2 was maintained at 40 ± 2 mmHg with intermittent positive pressure ventilation (IPPV). Body temperature, heart rate, indirect systemic arterial blood pressures, inspired and end-tidal CO2, volatile agent, N2O and O2 were recorded every 5 minutes. The vaporizer setting was decreased in 0.25–0.5% decrements to elicit a palpebral reflex, and this level maintained. Statistical analysis included two-way anova for repeated measures with Bonferroni's correction factor and statistical significance assumed when p < 0.05. Percentage reduction in end-tidal volatile agent was calculated at 60 minutes after starting study.Results End-tidal HAL, ISO and SEV decreased when N2O was administered. Percentage reduction: HAL (12.4%); ISO (37.1%) and SEV (21.4%). Diastolic, mean and systolic blood pressures increased in ISO/N2O compared with ISO. Heart rate increased in ISO/N2O and SEV/N2O compared with ISO and SEV, respectively. Systolic, mean and diastolic blood pressures increased in SEV compared with HAL and ISO. Systolic, mean, diastolic blood pressures and heart rate increased in SEV/N2O and ISO/N2O compared with HAL/N2O.Conclusions N2O reduces HAL, ISO and SEV requirements in dogs undergoing ovariohysterectomy. Cardiovascular stimulation occurred when N2O was used with ISO, less so with SEV and not with HAL.

Investigation of the genetic influence of the OPG, VDR (Fok1), and COLIA1 Sp1 polymorphisms on BMD in the Irish population.

Low bone mineral density (BMD) is a major risk factor for the development of osteoporosis and there is strong evidence to suggest that the procurement and preservation of peak BMD is genetically determined. In an effort to identify factors responsible for susceptibility to low BMD in the Irish population, we investigated its possible association with polymorphisms in the Osteoprotegerin (OPG) gene, Type I collagen alpha 1 (COLIA1) Sp1 binding site and vitamin D receptor (VDR) start codon. Following a systematic screening of the regulatory and coding regions of the OPG gene, we identified a novel G1181C polymorphism in exon 1 and a T950C polymorphism in the promoter region of the OPG gene. Participants were recruited from the Bone Densitometry Unit of Cork University Hospital, including 381 postmenopausal women aged 61.26 +/- 8.50 (mean +/- SD) and 130 premenopausal women aged 46.30 +/- 6.50 (mean +/- SD). Following association analysis using both the premenopausal and postmenopausal cohorts we found that postmenopausal women carrying one or more C alleles of the G1181C polymorphism had 14.8% lower BMD (P = 0.05) at the lumbar spine and 14.4% lower BMD (P = 0.04) at the FN. However, both were nonsignificant when the Bonferroni correction factor (0.01 significance level) was applied to correct for multiple hypothesis testing. We found no association between alleles of the T950C OPG polymorphism and BMD. Similarly, we have found a lack of association between the VDR (fok1) polymorphism or COLIA1 Sp1 polymorphism and low BMD in either postmenopausal or premenopausal women in this population.

An evaluation of alternative algorithms for fitting species distribution models using logistic regression

Logistic regression is being used increasingly to develop regional-scale predictive models of species distributions for use in regional conservation planning. These models are usually developed using automated stepwise procedures to select the explanatory variables to include in each model and to fit the functions relating each of these variables to the probability of species occurrence. Available procedures for fitting logistic regression models differ in terms of a number of factors, including the basic modelling technique employed (generalised linear or generalised additive modelling), the strategy used to select explanatory variables and to determine the complexity of fitted functions, and the approach used to correct for multiple testing. This study evaluates the effect that each of these factors has on the predictive accuracy of fitted models, using fauna and flora survey data from north-east New South Wales. The results suggest that predictive accuracy is maximised by employing variable selection procedures that stringently guard against the inclusion of extraneous variables in a model, such as forwards selection with a 5% significance level and removal of insignificant variables at each stage of the selection process. Models fitted using generalised additive modelling were more accurate than those derived using generalised linear modelling. The best approach to controlling the complexity of fitted models was less clear, as it tended to vary between the biological groups examined. Small reptile species were best modelled by complex relationships (3 or 4 df), and vascular plants and diurnal birds by simple relationships (1 or 2 df). Correction for multiple testing using the Bonferroni correction factor did not improve the accuracy of models.

Analysis of HLA association in susceptibility to infection with Cryptococcus neoformans var. gattii in a Papua New Guinean population

The possible association between susceptibility to infection with Cryptococcus neoformans var. gattii and HLA phenotype was examined in a group of Papua New Guinean patients. There was no evidence for a statistically significant association between susceptibility to infection and HLA class I and HLA class II phenotypes, although analysis of data which had not been subjected to the appropriate Bonferroni correction factor suggested a trend for susceptibility linked to HLA B*5601.

Analysis of HLA association in susceptibility to infection withCryptococcus neoformansvar.gattiiin a Papua New Guinean population

The possible association between susceptibility to infection with Cryptococcus neoformans var. gattii and HLA phenotype was examined in a group of Papua New Guinean patients. There was no evidence for a statistically significant association between susceptibility to infection and HLA class I and HLA class II phenotypes, although analysis of data which had not been subjected to the appropriate Bonferroni correction factor suggested a trend for susceptibility linked to HLA B*5601.

Clinical variables affecting the marginal degradation of amalgam restorations

The influence of different clinical variables on the marginal degradation of amalgam restorations was studied in a clinical trial of class-II amalgam restorations. Seven Scandinavian dentists using 5 different alloys placed 468 restorations in 210 patients. The marginal degradation was scored on impressions of the restored teeth by using a six-point ordinal rating scale and was transformed to ridit values. After 5 years 126 patients with 296 restorations remained in the trial. Ridit analysis and paired comparison tests utilizing the Bonferroni correction factor at each yearly interval indicated that the extent of degradation of the restoration margins was influenced by the location in the mouth, the position on the tooth, the type of alloy, and the operator. The results demonstrate that features of the cavity preparation and the handling of the material by the operator are more important for the degradation of the restoration margins than other clinical variables.