Guided endodontics: accuracy of access cavity preparation and discrimination of angular and linear deviation on canal accessing ability—an ex vivo study

Abstract Background Guided endodontics technique has been introduced for years, but the accuracy in different types of teeth has yet to be assessed. The aim of this study is to evaluate the accuracy of three dimensional (3D)-printed endodontic guides for access cavity preparation in different types of teeth, and to evaluate the predictive ability of angular and linear deviation on canal accessibility ex vivo. Method Eighty-four extracted human teeth were mounted into six jaw models and categorised into three groups: anterior teeth (AT), premolar (P), and molar (M). Preoperative cone beam computed tomography (CBCT) and surface scans were taken and matched using implant planning software. Virtual access cavity planning was performed, and templates were produced using a 3D printer. After access cavities were performed, the canal accessibility was recorded. Postoperative CBCT scans were superimposed in software. Coronal and apical linear deviations and angular deviations were measured and evaluated with nonparametric statistics. The receiver operating characteristic (ROC) curve was used to evaluate the predictive ability of angular and linear deviation for canal accessibility in SPSS v20. Results A total of 117 guided access cavities were created and 23 of them were record as canal inaccessibility, but all canals were accessible after canal negotiation. The average linear deviation for all groups was 0.13 ± 0.21 mm at coronal position, 0.46 ± 0.4 mm at apical position, and 2.8 ± 2.6° in angular deviation. At the coronal position, the linear deviations of the AT and P groups were significantly lower than M group deviation (P < 0.05), but no statistically significant difference between AT group and P group. The same results were found in linear deviation at the apical position and in angular deviation. The area under the ROC curve was 0.975 in angular deviation, 0.562 in linear deviation at the coronal position, and 0.786 at the apical position. Statistical significance was noted in linear deviation at the apical position and in angular deviation (P < 0.001). Conclusions In conclusion, this study demonstrated that the accuracy of access cavity preparation with 3D-printed endodontic guides was acceptable. The linear and angular deviations in the M group were significantly higher than those in the other groups, which might be caused by the interference of the opposite teeth. Angular deviation best discriminated the canal access ability of guided access cavity preparation. Graphical Abstract

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Guided Endodontics: Accuracy of Access Cavity Preparation and Discrimination of Angular and Linear Deviation On Canal Accessing Ability – An Ex Vivo Study

10.21203/rs.3.rs-787952/v1 ◽

2021 ◽

Author(s):

Ying-Hui Su ◽

Cheng-Hui Chen ◽

Chia-Hua Lin ◽

Hui-Na Lee ◽

Ker-Kong Chen ◽

...

Keyword(s):

Roc Curve ◽

Ex Vivo ◽

Predictive Ability ◽

Angular Deviation ◽

Cavity Preparation ◽

Apical Position ◽

Anterior Teeth ◽

Significant Difference ◽

Different Types ◽

3D Printed

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Fracture Strength and Marginal Adaptation of Conservative and Extended MOD Cavities Restored with Cention N

International Journal of Dentistry ◽

10.1155/2021/5599042 ◽

2021 ◽

Vol 2021 ◽

pp. 1-7

Author(s):

Maryam Firouzmandi ◽

Ali Asghar Alavi ◽

Dana Jafarpour ◽

Soroush Sadatsharifee

Keyword(s):

Fracture Strength ◽

Resin Composite ◽

Testing Machine ◽

Marginal Adaptation ◽

Cavity Preparation ◽

Universal Testing ◽

Significant Difference ◽

Different Types ◽

Maxillary Premolars ◽

Analyze Data

The aim of the present study was to compare the fracture strength and marginal adaptation of MOD cavities restored with Cention N, bonded Cention N, and resin composite, as well as to investigate the effect of cavity preparation volume on those properties. In this experimental study, 120 human maxillary premolars were randomly divided into six groups according to the type of restoration and cavity volume (n = 20): (I) conservative MOD restored with Cention N, (II) conservative MOD restored with bonded Cention N, (III) conservative MOD restored with Z250 resin composite, (IV) extended MOD restored with Cention N, (V) extended MOD restored with bonded Cention N, and (VI) extended MOD restored with Z250 resin composite. Fracture strength (MPa) was tested using a universal testing machine. To investigate marginal adaptation, polyvinyl-siloxane impressions were taken and poured with epoxy resin. Resin replicas were examined by SEM (×400) for marginal adaptation. ANOVA tests, Tukey’s test, and independent t-test were used to analyze data ( P ≤ 0.05). Among conservative restorations, the fracture strength of bonded Cention N was significantly greater than that of Cention N ( P = 0.001), while in the extended preparations, there was no significant difference between fracture strengths of different types of restorations ( P = 0.579). In terms of marginal adaptation, there was no significant difference between different types of conservative restorations ( P = 0.232). However, in extended preparations, composite showed significantly lower marginal adaptation than Cention N and bonded Cention N ( P = 0.004 and P = 0.045, respectively). Conservative preparations showed significantly greater fracture strength and marginal adaptation compared to extended ones in groups restored with composite. The volume of cavity preparation was shown to be effective in the materials fracture strength and marginal adaptation. Cention N showed promising results in terms of fracture strength and marginal adaptation.

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In vitro Assessment of Tooth Color Alteration by Two Different Types of Endodontic Irrigants

The Journal of Contemporary Dental Practice ◽

10.5005/jp-journals-10024-1574 ◽

2014 ◽

Vol 15 (5) ◽

pp. 529-533

Author(s):

Anastasios Dimitrios Koursoumis ◽

Nikolaos P Kerezoudis ◽

Afrodite Kakaboura

Keyword(s):

Root Canal ◽

Endodontic Treatment ◽

Cavity Preparation ◽

Tooth Color ◽

Color Changes ◽

Anterior Teeth ◽

Different Types ◽

In Vitro Assessment ◽

Color Alteration

ABSTRACT Aim The purpose of this study was to assess in vitro the tooth color alterations associated with two commonly used endodontic irrigants, the chlorhexidine gluconate (CHX) and the sodium hypochlorite (NaOCl) up to 15 days post-treatment. Additionally, the possible influence of endodontic access preparation on tooth color was investigated. Materials and methods Thirty intact human anterior teeth were used. Black adhesive tape with a 4 mm diameter window was used to standardize the enamel surface intended for color analysis. After the access cavity, preparation and the initial root canal negotiation with stainless steel hand files, the root canal shaping was completed with rotary nickel-titanium files. The teeth were divided into three groups (n = 10). Conventional syringe irrigation was performed with one irrigant for each group. The enamel surfaces were colorimetrically evaluated before access cavity, after cavity preparation and at 1, 3, 7 and 15 days post-treatment. The CIE color parameters (L*, a*, b*) were recorded and averaged for each material and the corresponding color differences (ΔE) were calculated and statistically analyzed. Results The most significant factor in tooth color alteration, during the endodontic treatment, was the access preparation. CHX and NaOCl caused tooth color changes comparable with the saline. CHX and NaOCl did not increase the tooth color changes relative to the values induced by the access preparation. Conclusion The two endodontic irrigants were not able to induce tooth color alteration to a greater extent than the access preparation. Clinical significance Chlorhexidine and NaOCl cannot be considered as discoloring endodontic materials. The most contributing factor in tooth color alteration during endodontic treatment in the anterior teeth is access preparation. How to cite this article Koursoumis AD, Kerezoudis NP, Kakaboura A. In vitro Assessment of Tooth Color Alteration by Two Different Types of Endodontic Irrigants. J Contemp Dent Pract 2014;15(5):529-533.

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Households Discrimination in School Enrolment in Pakistan: Does gender matter?

Journal of Applied Economics and Business Studies ◽

10.34260/jaebs.213 ◽

2018 ◽

Vol 2 (1) ◽

pp. 29-36

Author(s):

Ali Muhammad ◽

Zahoor Ul Haq ◽

Imad Khan

Keyword(s):

Low Income ◽

Gender Discrimination ◽

Rural Areas ◽

Gender Disparity ◽

School Enrollment ◽

Female Education ◽

Public And Private ◽

Significant Difference ◽

Different Types ◽

Socio Economic Factors

This study uses Pakistan Social and Living Measurement Survey 2016 to study gender discrimination in school enrollment across the four provinces of Pakistan using bi-variate analysis. Results show that there is highly significant difference between male and female education in rural areas (x^2=4940.50 and p<0.05). Analysis indicate that gender disparity in enrollment is significantly higher in low income households (x^2=115.468 and P<0.05). The study also showed that as compared to male, fewer female are enrolled in both public and private sectors. Hence, socio-economic factors play important role in making decision about children enrollment in different types of school. The study recommends that government to take appropriate steps to reduce gender discrimination in school enrollment by offering subsidy on female education in the country.

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Using Histological and Chemical Methods for Detection of Unauthorized Tissues Addition in Emulsion Type Meat Product

International Journal of Veterinary Science ◽

10.37422/ijvs/033 ◽

2020 ◽

Keyword(s):

Vascular Tissue ◽

Meat Product ◽

Calcium Content ◽

Processed Meat ◽

Low Protein ◽

Significant Difference ◽

Different Types ◽

Plant Stem ◽

High Level ◽

Reliable Methods

Total twenty different processed meat plant producing emulsion type sausage were histologically and chemically examined for detection of adulteration with unauthorized tissues. Results revealed that samples were adulterated with different types of animal tissues included; hyaline cartilage, tendon, spongy bone, peripheral nerve trunk, basophilic matrix, lymphatic tissue, fascia, fibrocartilage and vascular tissue. Moreover, these samples were adulterated Also, adulterated with plant tissue included; plant stem, leaves and root. Chemical analysis showed a significant difference in their chemical composition (moisture, fat, protein, ash and calcium) content. Moisture and fat content varied around the permissible limit of E.S.S. while low protein, high ash and calcium content was detected in the examined samples. Therefore, Histological and chemical examinations can be used as reliable methods to detect adultration using unauthorized addition of both animal and plant tissues in processed meat product samples which revealed a high level of falsification.

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Aerosol generation through pars plana vitrectomy

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2020-317214 ◽

2020 ◽

pp. bjophthalmol-2020-317214

Author(s):

Hasan Naveed ◽

Fong May Chew ◽

Hanbin Lee ◽

Edward Hughes ◽

Mayank A Nanavaty

Keyword(s):

Pars Plana Vitrectomy ◽

Ex Vivo ◽

Dynamic Changes ◽

Aerosol Generation ◽

Significant Difference ◽

Optical Particle Counter ◽

Pars Plana ◽

23 Gauge ◽

Set Up ◽

Ex Vivo Study

PurposeTo assess whether pars plana vitrectomy (PPV) is an aerosol-generating procedure (AGP) in an ex vivo experimental model.MethodsIn this ex vivo study on 10 porcine eyes, optical particle counter was used to measure particles ≤10 μm using cumulative mode in the six in-built channels: 0.3 μm, 0.5 μm, 1 μm, 2.5 μm, 5 μm and 10 μm aerosols during PPV. Two parts of the study were as follows: (1) to assess the pre-experimental baseline aerosol count in the theatre environment where there are dynamic changes in temperature and humidity and (2) to measure aerosol generation with 23-gauge and 25-gauge set-up. For each porcine eye, five measurements were taken for each consecutive step in the experiment including pre-PPV, during PPV, fluid–air exchange (FAX) and venting using a flute with 23-gauge set-up and a chimney with 25-gauge set-up. Therefore, a total of 200 measurements were recorded.ResultsWith 23-gauge and 25-gauge PPV, there was no significant difference in aerosol generation in all six channels comparing pre-PPV versus PPV or pre-PPV versus FAX. Venting using flute with 23-gauge PPV showed significant reduction of aerosol ≤1 μm. Air venting using chimney with 25-gauge set-up showed no significant difference in aerosol of ≤1 μm. For cumulative aerosol counts of all particles measuring ≤5 μm, compared with pre-PPV, PPV or FAX, flute venting in 23-gauge set-up showed significant reduction unlike the same comparison for chimney venting in 25-gauge set-up.ConclusionPPV and its associate steps do not generate aerosols ≤10 μm with 23-gauge and 25-gauge set-ups.

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The Influence of Force Direction on the Fracture Pattern and Fracture Resistance of Canine Teeth in Dogs

Journal of Veterinary Dentistry ◽

10.1177/0898756417705229 ◽

2017 ◽

Vol 34 (1) ◽

pp. 8-17 ◽

Cited By ~ 2

Author(s):

Stephanie Goldschmidt ◽

Catherine Zimmerman ◽

Caitlyn Collins ◽

Scott Hetzel ◽

Heidi-Lynn Ploeg ◽

...

Keyword(s):

Fracture Resistance ◽

Ex Vivo ◽

Testing Machine ◽

Fracture Pattern ◽

Hard Tissue ◽

Canine Tooth ◽

Cross Sectional ◽

Significant Difference ◽

Force Direction ◽

Testing Group

Biomechanical studies of the elongated canine tooth of animals are few, and thus our understanding of mechanical and physical properties of animal teeth is limited. The objective of the present study was to evaluate the influence of force direction on fracture resistance and fracture pattern of canine teeth in an ex vivo dog cadaver model. Forty-five extracted canine teeth from laboratory beagle dogs were standardized by hard tissue volume and randomly distributed among 3 force direction groups. The teeth were secured within a universal testing machine and a load was applied at different directions based on testing group. The maximum force to fracture and the fracture pattern classification were recorded for each tooth. After correcting for hard tissue cross-sectional area in a multivariate analysis, no significant difference in the amount of force required for fracture was apparent between the different force direction groups. However, the influence of force direction on fracture pattern was significant. The results of this study may allow the clinician to educate clients on possible causal force directions in clinically fractured teeth and, thus, help prevent any contributing behavior in the future.

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Predicting chromosome damage in astronauts participating in international space station missions

Scientific Reports ◽

10.1038/s41598-021-84242-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alan Feiveson ◽

Kerry George ◽

Mark Shavers ◽

Maria Moreno-Villanueva ◽

Ye Zhang ◽

...

Keyword(s):

International Space Station ◽

Dose Response ◽

Ex Vivo ◽

Space Station ◽

Space Radiation ◽

Blood Samples ◽

International Space ◽

Significant Difference ◽

Subject Specific

AbstractSpace radiation consists of energetic protons and other heavier ions. During the International Space Station program, chromosome aberrations in lymphocytes of astronauts have been analyzed to estimate received biological doses of space radiation. More specifically, pre-flight blood samples were exposed ex vivo to varying doses of gamma rays, while post-flight blood samples were collected shortly and several months after landing. Here, in a study of 43 crew-missions, we investigated whether individual radiosensitivity, as determined by the ex vivo dose–response of the pre-flight chromosome aberration rate (CAR), contributes to the prediction of the post-flight CAR incurred from the radiation exposure during missions. Random-effects Poisson regression was used to estimate subject-specific radiosensitivities from the preflight dose–response data, which were in turn used to predict post-flight CAR and subject-specific relative biological effectiveness (RBEs) between space radiation and gamma radiation. Covariates age, gender were also considered. Results indicate that there is predictive value in background CAR as well as radiosensitivity determined preflight for explaining individual differences in post-flight CAR over and above that which could be explained by BFO dose alone. The in vivo RBE for space radiation was estimated to be approximately 3 relative to the ex vivo dose response to gamma irradiation. In addition, pre-flight radiosensitivity tended to be higher for individuals having a higher background CAR, suggesting that individuals with greater radiosensitivity can be more sensitive to other environmental stressors encountered in daily life. We also noted that both background CAR and radiosensitivity tend to increase with age, although both are highly variable. Finally, we observed no significant difference between the observed CAR shortly after mission and at > 6 months post-mission.

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Role of Quantitative Diffusion-Weighted Imaging in Differentiating Benign and Malignant Orbital Masses

Indian Journal of Radiology and Imaging ◽

10.1055/s-0041-1730120 ◽

2021 ◽

Author(s):

Preeti Mundhada ◽

Sudarshan Rawat ◽

Ullas Acharya ◽

Dhananjay Raje

Keyword(s):

Roc Curve ◽

Diffusion Weighted Imaging ◽

Care Hospital ◽

Adc Value ◽

Diffusion Weighted ◽

Significant Difference ◽

Orbital Masses ◽

Adc Values ◽

Orbital Lesions

Abstract Aim To determine the role of diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) values in differentiating benign and malignant orbital masses. Materials and Methods After obtaining institutional ethical board approval and informed consent from all patients, an observational study was done for a period of 24 months in the radiology department of a tertiary care hospital in South India. Conventional magnetic resonance imaging and DWI using a 3T scanner was done for all patients with suspected orbital mass lesion. ADC value and clinicohistopathological correlation were studied for every patient. Chi-square test was used to compare the signal characteristics of DWI and ADC maps between benign and malignant lesions. A comparison of mean ADC values for benign and malignant masses was performed using Student’s t-test for independent samples. The cut-off value for ADC was obtained using the receiver operating characteristic (ROC) curve. Results Of 44 patients with orbital lesions, 70% were benign and 30% were malignant. There was a significant difference in the mean ADC values of benign and malignant orbital masses. Using ROC curve analysis, an optimal ADC threshold of 1.26 × 10−3 mm2/s was calculated for the prediction of malignancy with 100% sensitivity, 80.65% specificity, and 86.36% accuracy (95% confidence interval: 0.872, 1.00, p < 0.0001). Two ADC thresholds were used to characterize the orbital masses with more than 90% confidence. Conclusion Quantitative assessment of ADC is a useful noninvasive diagnostic tool for differentiating benign and malignant orbital masses. Malignant orbital lesions demonstrate significantly lower ADC values as compared with benign lesions.

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Accuracy of the fluorescence-aided identification technique (FIT) for detecting tooth-colored restorations utilizing different fluorescence-inducing devices: an ex vivo comparative study

Clinical Oral Investigations ◽

10.1007/s00784-021-03826-7 ◽

2021 ◽

Author(s):

W. Leontiev ◽

E. Magni ◽

C. Dettwiler ◽

C. Meller ◽

R. Weiger ◽

...

Keyword(s):

Multivariate Analysis ◽

Ex Vivo ◽

Predictive Values ◽

Composite Restorations ◽

Significant Difference ◽

Identification Technique ◽

Illumination Method ◽

Sensitivity Specificity ◽

Entire Procedure ◽

Higher Sensitivity

Abstract Objectives The aim of the present study was to compare the accuracy of the conventional illumination method (CONV) and the fluorescence-aided identification technique (FIT) for distinguishing between composite restorations and intact teeth using different fluorescence-inducing devices commonly used for FIT. Materials and methods Six groups of six dentists equipped with one of six different FIT systems each independently attempted to identify composite restorations and intact teeth on a full-mouth model with 22 composite restorations using CONV and, 1 h later, FIT. The entire procedure was repeated 1 week later. Sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values, including 95% confidence intervals (CI), were calculated for CONV and FIT overall and for each device. The influence of examiner age, method, and device on each parameter was assessed by multivariate analysis of variance. Results The sensitivity (84%, CI 81–86%), specificity (94%, CI 93–96%), PPV (92%, CI 90–94%), and NPV (90%, CI 88–91%) of FIT was significantly higher than that of CONV (47%, CI 44–50%; 82%, CI 79–84%; 66%, CI 62–69%, and 69%, CI 68–71%, respectively; p<0.001). The differences between CONV and FIT were significant for all parameters and FIT systems except VistaCam, which achieved no significant difference in specificity. Examiners younger than 40 years attained significantly higher sensitivity and negative predictive values than older examiners. Conclusions FIT is more reliable for detecting composite restorations than the conventional illumination method. Clinical relevance FIT can be considered an additional or alternative tool for improving the detection of composite restorations.

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