Influence of apical preparation size and final irrigation protocol on the debridement of oval root canals

2021 ◽  
Vol 32 (6) ◽  
pp. 16-27
Author(s):  
Carolina Pessoa Stringheta ◽  
Rina Andréa Pelegrine ◽  
Victor Angelo Martins Montalli ◽  
James L Gutmann ◽  
Carlos Eduardo da Silveira Bueno
Keyword(s):  
Generalized Linear Models ◽  
Histological Analysis ◽  
Linear Models ◽  
Ethylenediaminetetraacetic Acid ◽  
Root Canals ◽  
Significant Difference ◽  
Digital Microscope ◽  
Specimen Processing ◽  
The Difference ◽  
Conventional Irrigation

Abstract This study assessed the influence of apical preparation size and final irrigation protocol on the debridement of the apical third of oval root canals of mandibular molars. Seventy-seven distal roots were divided into 7 groups (n = 11): Control: without instrumentation or irrigation; Group 30CI: ProTaper Next (up to size 30; PTN) + conventional irrigation (CI); Group 30UAI: PTN + ultrasonically activated irrigation (UAI); Group 30XPF: PTN + XP-endo Finisher (XPF); Group 40CI: PTN + ProDesign Logic (up to size 40; PDL) + CI; Group 40UAI: PTN + PDL + UAI; and Group 40XPF: PTN + PDL + XPF. The total volume of irrigating solutions used per root canal in all the experimental groups was 33 mL of 2.5% sodium hypochlorite (NaOCl) and 6 mL of 17% ethylenediaminetetraacetic acid (EDTA). After specimen processing and histological analysis under a digital microscope (100x), the percentages of untouched canal walls (UCW) and remaining debris (RD) were assessed using Image J software. A descriptive and exploratory analysis was conducted, indicating that the data failed to meet the assumptions of an analysis of variance. Therefore, generalized linear models were used to assess the effects of the different instrumentation and irrigation protocols, as well as the interaction among them, on the percentage of UCW and RD. No significant difference was found among the irrigation protocols regarding the percentage of UCW, irrespective of apical preparation size (p>0.05). However, UCW and RD were significantly lower in groups 40CI, 40UAI and 40XPF than in groups 30CI, 30UAI and 30XPF (p<0.05). The percentage of RD was significantly lower in the UAI and XPF groups than in the CI groups, irrespective of apical preparation size (p<0.05). The difference between preparation sizes 30 and 40, with respect to RD, was higher when CI was used (p<0.05). In conclusion, instrumentation up to apical preparation size 40 resulted in lower percentages of UCW and RD than up to apical preparation size 30. Use of UAI or XPF resulted in lower percentages of RD than CI.

scholarly journals A Digital Microscopic Inspection of Dentinal Defects after Using Endodontic Retreatment Files

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Ammar AbuMostafa ◽  
Hala Almoqayyad ◽  
Al-Omari Mohammad
Keyword(s):  
Negative Control Group ◽  
Positive Control ◽  
Negative Control ◽  
Control Group ◽  
Filling Material ◽  
Root Canals ◽  
Root Canal Retreatment ◽  
Significant Difference ◽  
Digital Microscope ◽  
Microscopic Inspection

Aim. The study aimed at evaluating the incidence of dentinal defects after root canal retreatment with ProTaper Universal retreatment (PTUR) and XP-endo Shaper and Finisher R (XP). Materials and Methods. Sixty extracted single-rooted human premolars were selected and divided into 4 groups of 15 teeth each. In the negative control group, the teeth were left unprepared. In the positive control group, the teeth were prepared with ProTaper Next and obturated with no further retreatment. In the PTUR and XP groups, the teeth were prepared and obturated followed by removal of the filling material at body temperature using PTUR and XP instruments, respectively. The roots were then sectioned at 3, 6, and 9 mm from the apex and observed under a digital microscope to detect defects. Results. PTUR group showed significantly higher ( p value <0.05) incidence of defects than the other groups. Comparison of no defects versus defects between groups in different areas of root canals demonstrated significant difference among the groups in the apical and cervical regions. Conclusion. Within the limitations of the present study, PTUR files created significantly more dentinal defects than XP files, with most of those defects at the cervical and apical areas of the root canals.

scholarly journals Investigation of the effects of different chelating solutions on the microhardness and surface roughness of root canal dentin

2019 ◽  
Vol 9 (1) ◽  
pp. 22-29
Author(s):  
Celalettin Topbaş ◽  
Özkan Adıgüzel ◽  
Özlem Çölgeçen
Keyword(s):  
Surface Roughness ◽  
Root Canal ◽  
Ethylenediaminetetraacetic Acid ◽  
Micro Hardness ◽  
Dentin Surface ◽  
Significant Difference ◽  
Diamond Saw ◽  
The Difference ◽  
Root Canal Dentin ◽  
Roughness Measurements

Introduction: The purpose of this study is to examine the effect of different chelating solutions on microhardness and surface roughness of root canal dentin. Methodology: The crowns of sixty recently extracted maxillary central incisors were separated by diamond burs from the cemento-enamel junction. Roots are divided longitudinally into two pieces with diamond saw. The obtained samples were embedded in autopolymeric-acrylic and the dentin-surfaces of the teeth were grounded. Micro-hardness and surface-roughness measurements were carried out before the chelating processes. First group, the specimens were treated with gel-formed 17% Ethylenediaminetetraacetic acid [EDTA] (JE), second group, specimens were treated with 17% Liquid-formed EDTA (LE), third group, specimens were treated with 20% Citric acid (CA), and the last group specimens were treated with 7% Maleic acid (MA) for 120 seconds. After application of the chelating agents, micro-hardness and surface-roughness measurements of all samples were performed again. The difference between the initial and final measurements was calculated and statistically analyzed. One Way Analysis of Variance ANOVA was used for statistical-analysis and statistically significant difference was observed between the groups (p <0.05). Results: According to the test results, the microhardness of LE was statistically equal to that of JE and caused the least decrease in micro-hardness, SA decreased micro-hardness more than LE and JE, and MA decreased dentin micro-hardness more than all other solutions. And surface-roughness results are: MA increased surface-roughness more than other groups, SA and JE less roughened the dentin surface than MA, and there was no significant difference between the two solutions, LE caused less increase in dentin surface roughness compared to all solutions. Conclusions: Besides the use of EDTA and SA, the clinical use of MA can be considered, and it should also be noted that EDTA differs in terms of surface roughness between liquid and gel forms.   How to cite this article: Topbaş C, Adıgüzel Ö, Çölgeçen Ö. Investigation of the effects of different chelating solutions on the microhardness and surface roughness of root canal dentin. Int Dent Res 2019;9(1):22-9.   Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Interpretation and Implications of Lognormal Linear Regression Used for Bacterial Enumeration

2020 ◽  
Vol 103 (4) ◽  
pp. 1105-1111
Author(s):  
Anli Gao ◽  
Jennifer Fischer-Jenssen ◽  
Charles Wroblewski ◽  
Perry Martos
Keyword(s):  
Linear Regression ◽  
Normal Distribution ◽  
Generalized Linear Models ◽  
Error Term ◽  
Linear Models ◽  
Target Concentration ◽  
Percent Recovery ◽  
Significant Difference ◽  
Bacterial Enumeration ◽  
Statistical Results

Abstract Background Bacterial enumeration data are typically log transformed to realize a more normal distribution and stabilize the variance. Unfortunately, statistical results from log transformed data are often misinterpreted as data within the arithmetic domain. Objective To explore the implication of slope and intercept from an unweighted linear regression and compare it to the results of the regression of log transformed data. Method Mathematical formulae inferencing explained using real dataset. Results For y=Ax+B+ε, where y is the recovery (CFU/g) and x is the target concentration (CFU/g) with error ε homogeneous across x. When B=0, slope A estimates percent recovery R. In the regression of log transformed data, logy=αlogx+β+εz (equivalent to equation y=Axα·ω), it is the intercept β=logyx=logA that estimates the percent recovery in logarithm when slope α=1, which means that R doesn’t vary over x. Error term ω is multiplicative to x, while εz or log(ω) is additive to log(x). Whether the data should be transformed or not is not a choice, but a decision based on the distribution of the data. Significant difference was not found between the five models (the linear regression of log transformed data, three generalized linear models and a nonlinear model) regarding their predicted percent recovery when applied to our data. An acceptable regression model should result in approximately the best normal distribution of residuals. Conclusions Statistical procedures making use of log transformed data should be studied separately and documented as such, not collectively reported and interpreted with results studied in arithmetic domain. Highlights The way to interpret statistical results developed from arithmetic domain does not apply to that of the log transformed data.

scholarly journals Detection of Enterococcus faecalis in Necrotic Teeth Root Canals by Culture and Polymerase Chain Reaction Methods

2007 ◽  
Vol 01 (04) ◽  
pp. 216-221 ◽  
Author(s):  
Dilsah COGULU ◽  
Atac UZEL ◽  
Ozant ONCAG ◽  
Semiha d AKSOY ◽  
Cemal ERONAT
Keyword(s):  
Polymerase Chain Reaction ◽  
Enterococcus Faecalis ◽  
Permanent Teeth ◽  
Deciduous Teeth ◽  
Chain Reaction ◽  
Test Species ◽  
Root Canals ◽  
Significant Difference ◽  
Polymerase Chain ◽  
The Difference

ABSTRACTObjectives: The aim of this study was to investigate the presence of Enterococcus faecalis in endodontic infections in both deciduous and permanent teeth by culture and polymerase chain reaction (PCR) methods.Methods: A total of 145 children aged 5-13 years old were involved in this study. The presence of E. faecalis in necrotic deciduous and permanent teeth root canals was studied using culture and polymerase chain reaction methods.Results: Among 145 molar teeth, 57% (n=83) presented necrotic asymptomatic pulp tissues and were included in this study. Culture and PCR methods detected the test species in 18 and 22 of 83 teeth involved, respectively. E. faecalis was cultured from 8 (18%) of 45 necrotic deciduous teeth and from 10 (26%) of 38 necrotic permanent teeth. PCR detection identified the target species in 10 (22%) and 12 (32%) of necrotic deciduous and permanent teeth respectively. Statistically significant difference in the presence of E. faecalis in deciduous and permanent teeth was found by culture and PCR methods (P=0.03 and 0.02, respectively). The difference in the presence of E. faecalis between two different methods was not statistically significant (P>.05).Conclusions: The results of the present study confirm that both culture and PCR methods are sensitive to detect E. faecalis in root canals. (Eur J Dent 2007;1:216-221)

scholarly journals Performance of RaCe Instrumentation System in Curved Root Canals: A Comprehensive Analysis by Three Study Methods

2013 ◽  
Vol 24 (3) ◽  
pp. 230-234 ◽  
Author(s):  
Denise Piotto Leonardi ◽  
Gilson Blitzkow Sydney ◽  
Mario Tanomaru Filho ◽  
Flares Baratto-Filho ◽  
Samantha Schaffer Pugsley Baratto ◽  
...  
Keyword(s):  
Root Canal ◽  
Histological Analysis ◽  
Wilcoxon Test ◽  
Study Methods ◽  
Root Canals ◽  
Working Length ◽  
Apical Transportation ◽  
Significant Difference ◽  
Canal Enlargement ◽  
Curved Root Canals

In this study, curved maxillary molar root canals were instrumented with RaCe rotary system to evaluate: 1. the occurrence of canal transportation using a radiographic platform; 2. the action of the instruments on the dentin walls, centering ability and canal enlargement by analysis of digital images; and the percentage of regular dentin surfaces and debris within the canal by histological analysis. Ten mesiobuccal roots of extracted human maxillary molars were embedded in acrylic resin and sectioned at the middle and apical thirds. Root canal shaping was performed using the RaCe rotary system at 250 rpm and 1 Ncm torque. Each instrument set was used five times according to a crown-down technique in the following sequence: 40/0.10, 35/0.08, 25/0.06, 25/0.04, 25/0.02 (working length - WL), 30/0.02 (WL) and 35/0.02 (WL). Each instrument was inserted until resistance was felt and then pulled back, followed by brushing movements towards all canal walls. Each specimen was assessed by three study methods: radiographic platform, digitized image assessment and histological analysis. The radiographic platform showed lack of apical transportation. No statistically significant difference (Wilcoxon test, p>0.05) was found between the middle and apical thirds regarding instrument action on dentin walls, centering ability, area of root canal enlargement, percentage of regular dentin surfaces and debris within the root canal. It may be concluded that RaCe system is a suitable method for the preparation of curved root canals, regarding the maintenance of root canal original path, action on dentin walls, canal enlargement and removal of debris from the root canal lumen.

scholarly journals Histological analysis of the periapical tissues of dog deciduous teeth after root canal filling with diferent materials

2005 ◽  
Vol 13 (3) ◽  
pp. 318-324 ◽  
Author(s):  
Sueli Satomi Murata ◽  
Roberto Holland ◽  
Valdir de Souza ◽  
Eloi Dezan Junior ◽  
Juliana Aguiar de Grossi ◽  
...  
Keyword(s):  
Root Canal ◽  
Histological Analysis ◽  
Tissue Reaction ◽  
The Other ◽  
Deciduous Teeth ◽  
Control Group ◽  
Root Canal Filling ◽  
Root Canals ◽  
Anterior Teeth ◽  
Significant Difference

The problem of finding an ideal material for filling root canals of deciduous teeth has not been solved yet. This fact led to the development of an experiment to histologically analyze the periapical tissue reaction to 3 root canal filling materials. Eighty root canals of dog deciduous anterior teeth from 6 animals, 60 days old, were used in this study. After biomechanical preparation, the root canals were filled with the following materials: slowly resorbable Maisto paste, Sealer 26 with iodoform, L&C paste (calcium hydroxide with olive oil) and as a control group, canals that were prepared but not filled. At thirty days after the treatment the animals were killed and the teeth prepared for histological analysis. The materials were ranked statistically from the best to the worst as follows: a - Maisto paste, b - Sealer 26 with iodoform, c - control group, d - L&C paste. There was significant difference (p = 0.01) only when the results of the other groups were compared with the L&C paste group. It was also observed that L&C paste was not biologically compatible and that the other materials were biocompatible but their resorption was not at the same rate as that of the deciduous teeth roots.

scholarly journals Estimation of breeding values for mean and dispersion, their variance and correlation using double hierarchical generalized linear models

2012 ◽  
Vol 94 (6) ◽  
pp. 307-317 ◽  
Author(s):  
M. FELLEKI ◽  
D. LEE ◽  
Y. LEE ◽  
A. R. GILMOUR ◽  
L. RÖNNEGÅRD
Keyword(s):  
Random Effects ◽  
Generalized Linear Models ◽  
Linear Models ◽  
Estimation Algorithm ◽  
Least Square ◽  
Residual Variance ◽  
Hierarchical Generalized Linear Models ◽  
Genetic Components ◽  
The Difference ◽  
Variance Component Estimates

SummaryThe possibility of breeding for uniform individuals by selecting animals expressing a small response to environment has been studied extensively in animal breeding. Bayesian methods for fitting models with genetic components in the residual variance have been developed for this purpose, but have limitations due to the computational demands. We use the hierarchical (h)-likelihood from the theory of double hierarchical generalized linear models (DHGLM) to derive an estimation algorithm that is computationally feasible for large datasets. Random effects for both the mean and residual variance parts of the model are estimated together with their variance/covariance components. An important feature of the algorithm is that it can fit a correlation between the random effects for mean and variance. An h-likelihood estimator is implemented in the R software and an iterative reweighted least square (IRWLS) approximation of the h-likelihood is implemented using ASReml. The difference in variance component estimates between the two implementations is investigated, as well as the potential bias of the methods, using simulations. IRWLS gives the same results as h-likelihood in simple cases with no severe indication of bias. For more complex cases, only IRWLS could be used, and bias did appear. The IRWLS is applied on the pig litter size data previously analysed by Sorensen & Waagepetersen (2003) using Bayesian methodology. The estimates we obtained by using IRWLS are similar to theirs, with the estimated correlation between the random genetic effects being −0·52 for IRWLS and −0·62 in Sorensen & Waagepetersen (2003).

scholarly journals Endodontic retreatment of curved root canals using the dual wavelength erbium, chromium:yttrium, scandium, gallium, garnet, and diode 940-nm lasers and the XP-Endoshaper/finisher technique

2020 ◽  
Vol 4 (4) ◽  
pp. 211-216
Author(s):  
Riman Nasher ◽  
Ralf-Dieter Hilgers ◽  
Norbert Gutknecht
Keyword(s):  
Duty Cycle ◽  
Laser Scanning ◽  
Ethylenediaminetetraacetic Acid ◽  
Smear Layer ◽  
Dual Wavelength ◽  
Apical Region ◽  
Root Canals ◽  
Significant Difference ◽  
Endodontic Retreatment ◽  
Curved Root Canals

Abstract Purpose The aim of this quantitative study was to compare between a dual-wavelength laser (Er,Cr:YSGG, diode 940 nm) to the XP-Endoshaper/finisher combined with ethylenediaminetetraacetic acid (EDTA) 17% technique in removing secondary smear layer created during endodontic retreatment of curved canals. Methods Twenty-four human curved root canals were endodontically prepared and filled with AH-sealer and Reciproc® Gutta percha cones. The fillings were removed after 6 weeks, and the samples were randomly divided into 3 groups: A, negative control: irrigated with distilled water; B, XP-Endoshaper/finisher with EDTA 17%; and C Er,Cr:YSGG (2 W, 20 Hz, 50 μs) and diode 940 nm (2 W, 50% duty cycle). The canals were split longitudinally, and a laser scanning microscope (VK-X100K, VK-X200K, Keyence, Osaka, Japan) was used to capture images with the magnification of × 1000 from the canals. The images were scored by three blinded dentists using the Hülsmann scoring system, and a statistical analysis was carried out. Results A significant difference between the apical regions of groups B and C (p = 0.0010) was observed, with group C showing a cleaner apical region. However, this difference is cancelled out when comparing all areas of the canals (t = 1.43, df 21 p = 0.1663). Conclusion Within the limitations of this study, it can be concluded that a dual laser wavelength protocol (Er,Cr:YSGG (2 W, 20 Hz, 50 μs) and diode 940 nm (2 W, 50% duty cycle) may be positive in removing the secondary smear layer formed during endodontic retreatment cases of curved root canals.

scholarly journals Test time assessment on student's performance of statistics subjects by generalized linear models

2021 ◽  
Vol 10 (9) ◽  
pp. e8310917883
Author(s):  
Esttefani Duarte Brum ◽  
Gilberto Rodrigues Liska ◽  
Alisson Darós Santos
Keyword(s):  
Logistic Regression ◽  
Generalized Linear Models ◽  
Logistic Regression Model ◽  
Linear Models ◽  
Test Time ◽  
The Feminine ◽  
Student’S Performance ◽  
The Difference ◽  
Development Evaluation ◽  
Time Assessment

Can the time it takes a student to complete a test influence his / her performance? To answer this question, the logistic regression model was considered. In its development, evaluation was considered as a way of quantifying the performance of a student reflecting his degree of knowledge in a given content. For this we use records of the initial and final moments when developing an evaluation. The records of time spent were obtained from five different undergraduate classes, with subjects taught by the same teacher, with the same theoretical content, at the same university. The results confirm statistically that each additional minute that the student remains taking the test, implies in greater chances of obtaining good performance, as well as differences of performance between the feminine and masculine genders, although not statistically different, demonstrating that feminine students have greater chances of reaching the average. The model also confirms, according to the odds ratios that during the evaluations the students' performance decreases, having the best score in the first test. Through the references consulted, we understand that the difference in the grades of each student is influenced by several factors, the result of their own experiences.

scholarly journals Reflections on modern methods: generalized linear models for prognosis and intervention—theory, practice and implications for machine learning

2020 ◽  
Author(s):  
Kellyn F Arnold ◽  
Vinny Davies ◽  
Marc de Kamps ◽  
Peter W G Tennant ◽  
John Mbotwa ◽  
...  
Keyword(s):  
Machine Learning ◽  
Generalized Linear Models ◽  
Functional Form ◽  
Linear Models ◽  
Causal Explanation ◽  
Causal Modelling ◽  
Prediction And Prevention ◽  
Modern Methods ◽  
The Difference ◽  
Health Applications

Abstract Prediction and causal explanation are fundamentally distinct tasks of data analysis. In health applications, this difference can be understood in terms of the difference between prognosis (prediction) and prevention/treatment (causal explanation). Nevertheless, these two concepts are often conflated in practice. We use the framework of generalized linear models (GLMs) to illustrate that predictive and causal queries require distinct processes for their application and subsequent interpretation of results. In particular, we identify five primary ways in which GLMs for prediction differ from GLMs for causal inference: (i) the covariates that should be considered for inclusion in (and possibly exclusion from) the model; (ii) how a suitable set of covariates to include in the model is determined; (iii) which covariates are ultimately selected and what functional form (i.e. parameterization) they take; (iv) how the model is evaluated; and (v) how the model is interpreted. We outline some of the potential consequences of failing to acknowledge and respect these differences, and additionally consider the implications for machine learning (ML) methods. We then conclude with three recommendations that we hope will help ensure that both prediction and causal modelling are used appropriately and to greatest effect in health research.

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