Aim To evaluate the effect of acid‐etch procedures on the compressive strength and surface micro... more Aim To evaluate the effect of acid‐etch procedures on the compressive strength and surface microhardness of tooth‐coloured mineral trioxide aggregate (MTA).Methodology White ProRoot MTA (Dentsply Tulsa Dental) was mixed and packed into cylindrical tubes of 4 mm in diameter and 6 mm in height. Three groups, each of 15 specimens were subjected to an acid‐etch procedure either 4, 24 or 96 h after mixing. The compressive strength was measured and compared with unetched control groups. Differences between groups were analysed using the Kruskall–Wallis test. A further batch of cylindrical specimens of 6 mm in diameter and 12 mm in height were prepared for testing surface microhardness. Three groups of 15 specimens were subjected to the acid‐etch procedure at either 4, 24 or 96 h following mixing. Data were subjected to one‐way anova. Changes in the surface microstructure before and after the acid‐etch procedures were analysed using a scanning electron microscope (SEM).Results There was...
A living thing is distinguished from a dead thing by the multiplicity of the changes at any momen... more A living thing is distinguished from a dead thing by the multiplicity of the changes at any moment taking place in it Herbert Spencer This report provides general guidelines for the structure of a curriculum, followed by specific advice on the principles of learning and teaching, the process of restructuring and change leadership and management. It provides examples of several educational philosophies, including vertical and horizontal integration. It discusses the use of competence, learning outcomes, level of degree and assessment and provides a number of recommendations. It does not seek to be prescriptive of time allocation to disciplines within a curriculum. Although this report has been written primarily for those who will develop an undergraduate curriculum, the information may be sufficiently generic to apply to the recent development in graduate entry (‘shortened dental ’ or ‘accelerated’) courses and to postgraduate degree planning and higher education certificate or diplo...
AIM To critically evaluate the reporting quality of a random sample of clinical trials published ... more AIM To critically evaluate the reporting quality of a random sample of clinical trials published in Endodontics against the PRIRATE 2020 checklist and to analyse the association between the quality of reported trials and a variety of parameters. METHODOLOGY Fifty randomized clinical trials relating to Endodontics were randomly selected from the PubMed database from 2015 to 2019 and evaluated by two independent reviewers. For each trial, a score of '1' was awarded when it fully reported each item in the PRIRATE guidelines whereas a score of '0' was awarded when an item was not reported; when the item was reported inadequately a score of '0.5' was awarded. For the items that were not relevant to the trial, 'Not Applicable (NA)' was given. Based on the interquartile range of the overall scores received, trials were categorized into 'Low' (0-58.4%), 'Moderate' (58.5-72.8%) and 'High' (72.9-100%) quality. The associations between characteristics and quality of clinical trials were investigated. Descriptive statistics, frequency analysis and percentage analyses were used to describe the data. To determine the significance of categorical data, the chi-square test was used. The probability value 0.05 was considered as the level of significance. RESULTS Based on the overall scores, 13 (26%), 25(50%) and 12 (24%) of the reports of clinical trials were categorized as 'High', 'Moderate' and 'Low' quality, respectively. Three items (1b, 6d, 11e) were adequately reported in all manuscripts whilst two items (5k, 5m) were scored 'NA' in all the reports. The reports published from Europe had a significantly greater percentage of 'High'-quality scores, compared to Asia, Middle East, North America and South America (P = 0.0002). The 'High'-quality reports were published significantly more often in impact factor journals (P = 0.045). Reports of clinical trials published in journals that adhered to the CONSORT guidelines had significantly more 'High' scores compared to those that did not (P = 0.008). Clinical trials with protocols registered a priori had a significantly greater percentage of 'High' scores compared to the trials that were not registered in advance (P = 0.003). No significant difference occurred between the quality of clinical trials and the number of authors, journal (Endodontic specialty vs. Non-Endodontic specialty) or year of publication. CONCLUSIONS Reports of randomized clinical trials published in the speciality of Endodontics had a substantial number of deficiencies. To create high-quality reports of clinical trials, authors should comply with the PRIRATE 2020 guidelines.
Aim: The aim of this study is to compare the root canal shaping ability of two reciprocating inst... more Aim: The aim of this study is to compare the root canal shaping ability of two reciprocating instruments: WaveOne and Reciproc versus two rotary instruments – ProTaper Universal (PTU) and Mtwo. Materials and Methods: A total of 160 simulated root canals in resin blocks were constructed with two curvatures located at two positions creating four different combinations: 20°/8 mm, 20°/12 mm, 40°/8 mm, and 40°/12 mm. Canals were prepared using continuous rotation (PTU and Mtwo) or reciprocating (WaveOne and Reciproc) instruments according to the manufacturer's recommendations. Each system was used to prepare 10 canals of each shape. Each file or a set of files was used to prepare one canal. Using Image Analysis Software, pre- and post-instrumentation matching images were superimposed and analyzed for canal width and transportation. Instrument fractures, time of preparation, and change in working length were also recorded. The effect of instrument and canal type on shaping ability were analyzed using two-way ANOVA test followed by post hoc Pearson Chi-square test and sum of squares test at level of significance 5%. Results: The largest mean canal width and transportation values were associated with the Mtwo system (P < 0.001) and 40°/8 mm canals (P < 0.001). Canal aberrations were limited to rotary instruments mainly in canals with 40° curves. The reciprocating instruments prepared canals significantly faster than continuous rotation systems (P < 0.001). Conclusions: Continuous rotation and reciprocating files were safe and maintained the original canal anatomy. However, continuous rotation instruments have a higher tendency for canals transportation and aberrations, especially with larger curvatures. Reciprocating files were faster than continuous rotation files in shaping simulated root canals in resin blocks.
Laws and ethics require that before conducting human clinical trials, a new material, device or d... more Laws and ethics require that before conducting human clinical trials, a new material, device or drug may have to undergo animal testing in order to minimize the health risks to humans, unless suitable supporting grandfather data already exists. The Preferred Reporting Items for Animal Studies in Endodontology (PRIASE) 2021 guidelines were developed exclusively for the specialty of Endodontology by integrating and adapting the ARRIVE (Animals in Research: Reporting In Vivo Experiments) guidelines and the Clinical and Laboratory Images in Publications (CLIP) principles using a validated consensus-based methodology. The implementation of the PRIASE 2021 guidelines will reduce potential sources of bias and thus improve the quality, accuracy, reproducibility, completeness and transparency of reports describing animal studies in Endodontology. The PRIASE 2021 guidelines consist of a checklist with 11 domains and 43 individual items and a flowchart. The aim of the current document is to provide an explanation for each item in the PRIASE 2021 checklist and flowchart and is supplemented with examples from the literature in order for readers to understand their significance and to provide usage guidance. A link to the PRIASE 2021 explanation and elaboration document and PRIASE 2021 checklist and flowchart is available on the Preferred Reporting Items for study Designs in Endodontology (PRIDE) website (http://pride-endodonticguidelines.org/priase/).
Aim: This study evaluated the distortion and fracture mode of ProTaper and Mtwo rotary instrument... more Aim: This study evaluated the distortion and fracture mode of ProTaper and Mtwo rotary instruments following their use in severely curved root canals in extracted human teeth. Materials and Methods: A total of 30 mesial canals of mandibular molars were allocated into two groups that were balanced in terms of angle and radius of curvature. Canals were prepared by either ProTaper or Mtwo systems. Each set of instruments was changed after the third canal. Longitudinal and fractographic examinations of the instruments were carried out by scanning electron microscopy. Images were evaluated according to distortion and mode of fracture. Chi-square analysis and Fisher′s exact test were carried out at a significance level of P < 0.05. Results: No significant difference was found between fracture and distortion percentage of ProTaper and Mtwo rotary instruments (P > 0.05). Fractographic analysis revealed that all of the Mtwo instruments demonstrated torsional failure and all but one of the ProTaper instruments (S1) showed torsional failure. Conclusion: Fractographic examination of the fractured surface revealed shear fracture was the predominant mode of failure. Root canal curvature was an essential parameter influencing the susceptibility of instruments to fracture.
The relationship of the main foramen to the anatomic root apex has been the subject of several st... more The relationship of the main foramen to the anatomic root apex has been the subject of several studies. Although they are anatomically close, they rarely coincide, and their distance can vary according to age or tooth type, ranging from 0.2 to 3.0 mm. The aim of this short communication was to evaluate the distance between the main foramen of independent middle mesial canals (MMCs) and the anatomical mesial root apex of mandibular first molars using the micro-computed tomography. Twenty-five mandibular first molars with MMCs were scanned (resolution of 9.9 µm), and the distance from its main foramen to the anatomical apex was evaluated. Overall, the distance ranged from 0.2 to 2.4 mm; however, in 3 specimens the distance was greater than 3 mm. This report demonstrates that the exit of the main foramen of the MMC varies considerably and could approach a substantial distance from the anatomical apex greater than previously reported in the literature.
To test the null hypothesis that Carisolv is no more effective than 1% sodium hypochlorite in cle... more To test the null hypothesis that Carisolv is no more effective than 1% sodium hypochlorite in cleaning uninstrumented, immature root canals. A total of 240 uniform, immature ovine incisors were decoronated at the CEJ level and randomly divided into four groups of 60. After gross pulp extirpation, canals were flooded with normal saline (negative control), 1% NaOCl, Carisolv or 5% NaOCl (positive control) and incubated for 10 min (group 1), 20 min (group 2), 30 min (group 3) or 30 min, refreshing irrigant at 10 and 20 min (group 4). SEM photomicrographs of canal wall debris in the apical, middle and coronal thirds were scored against a 5-point scale. Internal consistency was assessed by kappa statistics. Debris scores for different irrigant regimes at different canal levels were analysed by non-parametric tests (P &amp;amp;lt; 0.05). Canals were consistently cleaner in the coronal and middle than apical thirds. NaOCl (5%) was consistently most effective. Carisolv and NaOCl (1%) were no more effective than normal saline in group 1 (P &amp;amp;gt; 0.05), but significantly more effective than normal saline in groups 2 (middle and apical 1/3), 3 and 4 (P &amp;amp;lt; 0.05). Carisolv and NaOCl (1%) had comparable activity in groups 1, 2 (middle and apical thirds) and 3, but NaOCl (1%) was significantly more effective than Carisolv in group 4 (coronal and middle thirds). 1. The ovine incisor model presents opportunities to investigate irrigation regimes under controlled ex-vivo conditions. 2.NaOCl (5%) remains the most effective irrigant for rapid debris removal in immature root canals. 3. Carisolv cleans pulp debris from the walls of immature root canals as effectively as NaOCl (1%) during static, unrefreshed wall contact for between 20 and 30 min. 4. Refreshment of NaOCl (1%) enhances its cleaning ability above that of Carisolv.
Biodentine (Septodont, Saint Maur des Fossés, France), OrthoMTA (BioMTA, Seoul, Korea), and EndoS... more Biodentine (Septodont, Saint Maur des Fossés, France), OrthoMTA (BioMTA, Seoul, Korea), and EndoSequence Root Repair Material (ERRM; Brasseler, Savannah, GA) have been developed to overcome the shortcomings of mineral trioxide aggregate (MTA). The purpose of this study was to compare tooth discoloration after the application of ProRoot MTA (Dentsply Tulsa Dental Products, Tulsa, OK) and 3 recently introduced calcium silicate-based cements in the presence and absence of blood. In total, 104 human anterior teeth were prepared; 96 were randomly divided into 2 groups (blood and saline contamination). Each group was subdivided into 4 experimental subgroups (n = 12) of ProRoot MTA, Biodentine, OrthoMTA, and ERRM that were used to fill the pulp chambers. The remaining 8 teeth served as the saline and blood groups. Color analysis of tooth crowns was performed using a spectroradiometer before the application of materials and at 24 hours, 1 month, and 6 months after application. Repeated measures analysis of variance was used to evaluate the effects of blood, material, and time on color change (ΔE*). Tooth color change in all experimental groups increased over time (P &amp;amp;amp;amp;lt; .05). Blood contamination significantly increased ΔE* (P &amp;amp;amp;amp;lt; .05), but no significant difference occurred between the 4 groups in this respect in the presence of blood. However, in the absence of blood, the ΔE* of Biodentine and ERRM was significantly less than that of OrthoMTA (P &amp;amp;amp;amp;lt; .05). There was no significant difference between tooth discolorations with materials in the presence of blood. However, in the absence of blood, Biodentine and ERRM exhibited less tooth discoloration than OrthoMTA.
This study compared the push-out bond strength of EndoSequence Root Repair Material (ERRM) and Bi... more This study compared the push-out bond strength of EndoSequence Root Repair Material (ERRM) and Bioaggregate (BA), new bioceramic materials, to that of mineral trioxide aggregate (MTA) after incubation in phosphate-buffered saline (PBS), a synthetic tissue fluid, for either 1 week or 2 months. One-hundred and twenty root sections were filled with ProRoot MTA, BA, or ERRM. Each tested material was then randomly divided into two subgroups (n = 20): root sections were immersed in PBS for 1 week or 2 months. The bond strengths were measured using a universal testing machine. After that, the failure modes were examined with stereomicroscopy and scanning electron microscopy (SEM). The push-out data and failure mode categories were analyzed by two-way ANOVA and chi-square tests, respectively. The bond strength of ERRM was significantly higher than that of BA and MTA at both incubation periods. No significant difference was found between the bond strength of MTA and BA at either 1 week or 2 ...
The purpose of this study was to evaluate the effect of acid etching on the compressive strength ... more The purpose of this study was to evaluate the effect of acid etching on the compressive strength of 4 calcium silicate-based cements. One gram of each corresponding powder of ProRoot MTA (Dentsply Tulsa Dental, Johnson City, TN), MTA Angelus (Angelus, Londrina, PR, Brazil), and CEM cement (BioniqueDent, Tehran, Iran) and a 0.33-g aliquot of liquid were placed in a plastic mixing capsule that was then mechanically mixed for 30 seconds at 4500 rpm in an amalgamator. For the preparation of Biodentine (Septodont, Saint Maur-des-Fossés, France), the liquid provided was added to the powder within the plastic capsule supplied by the manufacturer and then mechanically mixed for 30 seconds at 4500 rpm using the amalgamator. The resulting slurries were then placed incrementally into 40 cylindrical molds to give a total of 160 specimens that were incubated at 37°C for a week. Twenty specimens of each material were then subjected to the acid etch procedure. The compressive strength of the sampl...
This study assessed the shaping ability of RaCe rotary nickel-titanium instruments in simulated r... more This study assessed the shaping ability of RaCe rotary nickel-titanium instruments in simulated root canals. Forty simulated root canals consisting of four different shapes were prepared with RaCe rotary nickel-titanium instruments in a crowndown approach. Preoperative images were taken at the outset and postoperative images at various stages of preparation including at the conclusion of the shaping procedure. The combined images enabled assessment of aberrations and resin removal at various positions along the canal length. Overall, mean preparation time to size 40, .02 taper was 1.36 min. Thirty-three canals (83%) maintained the working length, three instruments deformed and no zips, perforations, or ledges were created. Under the conditions of this study RaCe rotary nickel-titanium instruments prepared simulated canals rapidly and successfully, with little change in working length and with few aberrations or instrument deformities.
A total of 160 simulated canals of various angles and positions of curvature were prepared by han... more A total of 160 simulated canals of various angles and positions of curvature were prepared by hand using either Mani Flexile Files, Mani SEC-O Files, Maillefer Flexofiles, or Zipperer Flexicut Files. After orifice enlargement, each file type was used to prepare 40 canals employing a balanced force motion and a modified double-flared technique. Pre- and postoperative images of the canals were taken with a videocamera, and stored and manipulated in a computer with image analysis software. The presence of canal aberrations and the amount of material removed as a result of preparation were determined from composite images of superimposed pre- and postoperative views. Significant differences (p < 0.001) in preparation time were observed, with Flexile Files being quickest and SEC-O Files being slowest. Overall, Flexofiles and Flexicut Files deformed significantly more (p < 0.001) than Flexile and SEC-O Files. The incidence of canal blockage was not influenced by instrument type, but...
The aim of this laboratory based study was to determine the shaping ability of Lightspeed nickel-... more The aim of this laboratory based study was to determine the shaping ability of Lightspeed nickel-titanium rotary instruments in simulated root canals. A total of 40 canals with four different shapes in terms of angle and position of curve were prepared with Lightspeed instruments using the stepback technique recommended by the manufacturer. This report describes the efficacy of the instruments in terms of prevalence of canal aberrations, the amount and direction of canal transportation, and overall postoperative shape. Preoperative and postoperative images of the canals were taken using a video camera attached to a computer with image analysis software. The preoperative and postoperative views were superimposed to highlight the amount and position of material removed during preparation. Only one (2.5%) zip and one elbow were created, with no ledges, perforations, danger zones, or blockages being produced. At specific points along the canal length there were highly significant differ...
Aim To evaluate the effect of acid‐etch procedures on the compressive strength and surface micro... more Aim To evaluate the effect of acid‐etch procedures on the compressive strength and surface microhardness of tooth‐coloured mineral trioxide aggregate (MTA).Methodology White ProRoot MTA (Dentsply Tulsa Dental) was mixed and packed into cylindrical tubes of 4 mm in diameter and 6 mm in height. Three groups, each of 15 specimens were subjected to an acid‐etch procedure either 4, 24 or 96 h after mixing. The compressive strength was measured and compared with unetched control groups. Differences between groups were analysed using the Kruskall–Wallis test. A further batch of cylindrical specimens of 6 mm in diameter and 12 mm in height were prepared for testing surface microhardness. Three groups of 15 specimens were subjected to the acid‐etch procedure at either 4, 24 or 96 h following mixing. Data were subjected to one‐way anova. Changes in the surface microstructure before and after the acid‐etch procedures were analysed using a scanning electron microscope (SEM).Results There was...
A living thing is distinguished from a dead thing by the multiplicity of the changes at any momen... more A living thing is distinguished from a dead thing by the multiplicity of the changes at any moment taking place in it Herbert Spencer This report provides general guidelines for the structure of a curriculum, followed by specific advice on the principles of learning and teaching, the process of restructuring and change leadership and management. It provides examples of several educational philosophies, including vertical and horizontal integration. It discusses the use of competence, learning outcomes, level of degree and assessment and provides a number of recommendations. It does not seek to be prescriptive of time allocation to disciplines within a curriculum. Although this report has been written primarily for those who will develop an undergraduate curriculum, the information may be sufficiently generic to apply to the recent development in graduate entry (‘shortened dental ’ or ‘accelerated’) courses and to postgraduate degree planning and higher education certificate or diplo...
AIM To critically evaluate the reporting quality of a random sample of clinical trials published ... more AIM To critically evaluate the reporting quality of a random sample of clinical trials published in Endodontics against the PRIRATE 2020 checklist and to analyse the association between the quality of reported trials and a variety of parameters. METHODOLOGY Fifty randomized clinical trials relating to Endodontics were randomly selected from the PubMed database from 2015 to 2019 and evaluated by two independent reviewers. For each trial, a score of '1' was awarded when it fully reported each item in the PRIRATE guidelines whereas a score of '0' was awarded when an item was not reported; when the item was reported inadequately a score of '0.5' was awarded. For the items that were not relevant to the trial, 'Not Applicable (NA)' was given. Based on the interquartile range of the overall scores received, trials were categorized into 'Low' (0-58.4%), 'Moderate' (58.5-72.8%) and 'High' (72.9-100%) quality. The associations between characteristics and quality of clinical trials were investigated. Descriptive statistics, frequency analysis and percentage analyses were used to describe the data. To determine the significance of categorical data, the chi-square test was used. The probability value 0.05 was considered as the level of significance. RESULTS Based on the overall scores, 13 (26%), 25(50%) and 12 (24%) of the reports of clinical trials were categorized as 'High', 'Moderate' and 'Low' quality, respectively. Three items (1b, 6d, 11e) were adequately reported in all manuscripts whilst two items (5k, 5m) were scored 'NA' in all the reports. The reports published from Europe had a significantly greater percentage of 'High'-quality scores, compared to Asia, Middle East, North America and South America (P = 0.0002). The 'High'-quality reports were published significantly more often in impact factor journals (P = 0.045). Reports of clinical trials published in journals that adhered to the CONSORT guidelines had significantly more 'High' scores compared to those that did not (P = 0.008). Clinical trials with protocols registered a priori had a significantly greater percentage of 'High' scores compared to the trials that were not registered in advance (P = 0.003). No significant difference occurred between the quality of clinical trials and the number of authors, journal (Endodontic specialty vs. Non-Endodontic specialty) or year of publication. CONCLUSIONS Reports of randomized clinical trials published in the speciality of Endodontics had a substantial number of deficiencies. To create high-quality reports of clinical trials, authors should comply with the PRIRATE 2020 guidelines.
Aim: The aim of this study is to compare the root canal shaping ability of two reciprocating inst... more Aim: The aim of this study is to compare the root canal shaping ability of two reciprocating instruments: WaveOne and Reciproc versus two rotary instruments – ProTaper Universal (PTU) and Mtwo. Materials and Methods: A total of 160 simulated root canals in resin blocks were constructed with two curvatures located at two positions creating four different combinations: 20°/8 mm, 20°/12 mm, 40°/8 mm, and 40°/12 mm. Canals were prepared using continuous rotation (PTU and Mtwo) or reciprocating (WaveOne and Reciproc) instruments according to the manufacturer's recommendations. Each system was used to prepare 10 canals of each shape. Each file or a set of files was used to prepare one canal. Using Image Analysis Software, pre- and post-instrumentation matching images were superimposed and analyzed for canal width and transportation. Instrument fractures, time of preparation, and change in working length were also recorded. The effect of instrument and canal type on shaping ability were analyzed using two-way ANOVA test followed by post hoc Pearson Chi-square test and sum of squares test at level of significance 5%. Results: The largest mean canal width and transportation values were associated with the Mtwo system (P < 0.001) and 40°/8 mm canals (P < 0.001). Canal aberrations were limited to rotary instruments mainly in canals with 40° curves. The reciprocating instruments prepared canals significantly faster than continuous rotation systems (P < 0.001). Conclusions: Continuous rotation and reciprocating files were safe and maintained the original canal anatomy. However, continuous rotation instruments have a higher tendency for canals transportation and aberrations, especially with larger curvatures. Reciprocating files were faster than continuous rotation files in shaping simulated root canals in resin blocks.
Laws and ethics require that before conducting human clinical trials, a new material, device or d... more Laws and ethics require that before conducting human clinical trials, a new material, device or drug may have to undergo animal testing in order to minimize the health risks to humans, unless suitable supporting grandfather data already exists. The Preferred Reporting Items for Animal Studies in Endodontology (PRIASE) 2021 guidelines were developed exclusively for the specialty of Endodontology by integrating and adapting the ARRIVE (Animals in Research: Reporting In Vivo Experiments) guidelines and the Clinical and Laboratory Images in Publications (CLIP) principles using a validated consensus-based methodology. The implementation of the PRIASE 2021 guidelines will reduce potential sources of bias and thus improve the quality, accuracy, reproducibility, completeness and transparency of reports describing animal studies in Endodontology. The PRIASE 2021 guidelines consist of a checklist with 11 domains and 43 individual items and a flowchart. The aim of the current document is to provide an explanation for each item in the PRIASE 2021 checklist and flowchart and is supplemented with examples from the literature in order for readers to understand their significance and to provide usage guidance. A link to the PRIASE 2021 explanation and elaboration document and PRIASE 2021 checklist and flowchart is available on the Preferred Reporting Items for study Designs in Endodontology (PRIDE) website (http://pride-endodonticguidelines.org/priase/).
Aim: This study evaluated the distortion and fracture mode of ProTaper and Mtwo rotary instrument... more Aim: This study evaluated the distortion and fracture mode of ProTaper and Mtwo rotary instruments following their use in severely curved root canals in extracted human teeth. Materials and Methods: A total of 30 mesial canals of mandibular molars were allocated into two groups that were balanced in terms of angle and radius of curvature. Canals were prepared by either ProTaper or Mtwo systems. Each set of instruments was changed after the third canal. Longitudinal and fractographic examinations of the instruments were carried out by scanning electron microscopy. Images were evaluated according to distortion and mode of fracture. Chi-square analysis and Fisher′s exact test were carried out at a significance level of P < 0.05. Results: No significant difference was found between fracture and distortion percentage of ProTaper and Mtwo rotary instruments (P > 0.05). Fractographic analysis revealed that all of the Mtwo instruments demonstrated torsional failure and all but one of the ProTaper instruments (S1) showed torsional failure. Conclusion: Fractographic examination of the fractured surface revealed shear fracture was the predominant mode of failure. Root canal curvature was an essential parameter influencing the susceptibility of instruments to fracture.
The relationship of the main foramen to the anatomic root apex has been the subject of several st... more The relationship of the main foramen to the anatomic root apex has been the subject of several studies. Although they are anatomically close, they rarely coincide, and their distance can vary according to age or tooth type, ranging from 0.2 to 3.0 mm. The aim of this short communication was to evaluate the distance between the main foramen of independent middle mesial canals (MMCs) and the anatomical mesial root apex of mandibular first molars using the micro-computed tomography. Twenty-five mandibular first molars with MMCs were scanned (resolution of 9.9 µm), and the distance from its main foramen to the anatomical apex was evaluated. Overall, the distance ranged from 0.2 to 2.4 mm; however, in 3 specimens the distance was greater than 3 mm. This report demonstrates that the exit of the main foramen of the MMC varies considerably and could approach a substantial distance from the anatomical apex greater than previously reported in the literature.
To test the null hypothesis that Carisolv is no more effective than 1% sodium hypochlorite in cle... more To test the null hypothesis that Carisolv is no more effective than 1% sodium hypochlorite in cleaning uninstrumented, immature root canals. A total of 240 uniform, immature ovine incisors were decoronated at the CEJ level and randomly divided into four groups of 60. After gross pulp extirpation, canals were flooded with normal saline (negative control), 1% NaOCl, Carisolv or 5% NaOCl (positive control) and incubated for 10 min (group 1), 20 min (group 2), 30 min (group 3) or 30 min, refreshing irrigant at 10 and 20 min (group 4). SEM photomicrographs of canal wall debris in the apical, middle and coronal thirds were scored against a 5-point scale. Internal consistency was assessed by kappa statistics. Debris scores for different irrigant regimes at different canal levels were analysed by non-parametric tests (P &amp;amp;lt; 0.05). Canals were consistently cleaner in the coronal and middle than apical thirds. NaOCl (5%) was consistently most effective. Carisolv and NaOCl (1%) were no more effective than normal saline in group 1 (P &amp;amp;gt; 0.05), but significantly more effective than normal saline in groups 2 (middle and apical 1/3), 3 and 4 (P &amp;amp;lt; 0.05). Carisolv and NaOCl (1%) had comparable activity in groups 1, 2 (middle and apical thirds) and 3, but NaOCl (1%) was significantly more effective than Carisolv in group 4 (coronal and middle thirds). 1. The ovine incisor model presents opportunities to investigate irrigation regimes under controlled ex-vivo conditions. 2.NaOCl (5%) remains the most effective irrigant for rapid debris removal in immature root canals. 3. Carisolv cleans pulp debris from the walls of immature root canals as effectively as NaOCl (1%) during static, unrefreshed wall contact for between 20 and 30 min. 4. Refreshment of NaOCl (1%) enhances its cleaning ability above that of Carisolv.
Biodentine (Septodont, Saint Maur des Fossés, France), OrthoMTA (BioMTA, Seoul, Korea), and EndoS... more Biodentine (Septodont, Saint Maur des Fossés, France), OrthoMTA (BioMTA, Seoul, Korea), and EndoSequence Root Repair Material (ERRM; Brasseler, Savannah, GA) have been developed to overcome the shortcomings of mineral trioxide aggregate (MTA). The purpose of this study was to compare tooth discoloration after the application of ProRoot MTA (Dentsply Tulsa Dental Products, Tulsa, OK) and 3 recently introduced calcium silicate-based cements in the presence and absence of blood. In total, 104 human anterior teeth were prepared; 96 were randomly divided into 2 groups (blood and saline contamination). Each group was subdivided into 4 experimental subgroups (n = 12) of ProRoot MTA, Biodentine, OrthoMTA, and ERRM that were used to fill the pulp chambers. The remaining 8 teeth served as the saline and blood groups. Color analysis of tooth crowns was performed using a spectroradiometer before the application of materials and at 24 hours, 1 month, and 6 months after application. Repeated measures analysis of variance was used to evaluate the effects of blood, material, and time on color change (ΔE*). Tooth color change in all experimental groups increased over time (P &amp;amp;amp;amp;lt; .05). Blood contamination significantly increased ΔE* (P &amp;amp;amp;amp;lt; .05), but no significant difference occurred between the 4 groups in this respect in the presence of blood. However, in the absence of blood, the ΔE* of Biodentine and ERRM was significantly less than that of OrthoMTA (P &amp;amp;amp;amp;lt; .05). There was no significant difference between tooth discolorations with materials in the presence of blood. However, in the absence of blood, Biodentine and ERRM exhibited less tooth discoloration than OrthoMTA.
This study compared the push-out bond strength of EndoSequence Root Repair Material (ERRM) and Bi... more This study compared the push-out bond strength of EndoSequence Root Repair Material (ERRM) and Bioaggregate (BA), new bioceramic materials, to that of mineral trioxide aggregate (MTA) after incubation in phosphate-buffered saline (PBS), a synthetic tissue fluid, for either 1 week or 2 months. One-hundred and twenty root sections were filled with ProRoot MTA, BA, or ERRM. Each tested material was then randomly divided into two subgroups (n = 20): root sections were immersed in PBS for 1 week or 2 months. The bond strengths were measured using a universal testing machine. After that, the failure modes were examined with stereomicroscopy and scanning electron microscopy (SEM). The push-out data and failure mode categories were analyzed by two-way ANOVA and chi-square tests, respectively. The bond strength of ERRM was significantly higher than that of BA and MTA at both incubation periods. No significant difference was found between the bond strength of MTA and BA at either 1 week or 2 ...
The purpose of this study was to evaluate the effect of acid etching on the compressive strength ... more The purpose of this study was to evaluate the effect of acid etching on the compressive strength of 4 calcium silicate-based cements. One gram of each corresponding powder of ProRoot MTA (Dentsply Tulsa Dental, Johnson City, TN), MTA Angelus (Angelus, Londrina, PR, Brazil), and CEM cement (BioniqueDent, Tehran, Iran) and a 0.33-g aliquot of liquid were placed in a plastic mixing capsule that was then mechanically mixed for 30 seconds at 4500 rpm in an amalgamator. For the preparation of Biodentine (Septodont, Saint Maur-des-Fossés, France), the liquid provided was added to the powder within the plastic capsule supplied by the manufacturer and then mechanically mixed for 30 seconds at 4500 rpm using the amalgamator. The resulting slurries were then placed incrementally into 40 cylindrical molds to give a total of 160 specimens that were incubated at 37°C for a week. Twenty specimens of each material were then subjected to the acid etch procedure. The compressive strength of the sampl...
This study assessed the shaping ability of RaCe rotary nickel-titanium instruments in simulated r... more This study assessed the shaping ability of RaCe rotary nickel-titanium instruments in simulated root canals. Forty simulated root canals consisting of four different shapes were prepared with RaCe rotary nickel-titanium instruments in a crowndown approach. Preoperative images were taken at the outset and postoperative images at various stages of preparation including at the conclusion of the shaping procedure. The combined images enabled assessment of aberrations and resin removal at various positions along the canal length. Overall, mean preparation time to size 40, .02 taper was 1.36 min. Thirty-three canals (83%) maintained the working length, three instruments deformed and no zips, perforations, or ledges were created. Under the conditions of this study RaCe rotary nickel-titanium instruments prepared simulated canals rapidly and successfully, with little change in working length and with few aberrations or instrument deformities.
A total of 160 simulated canals of various angles and positions of curvature were prepared by han... more A total of 160 simulated canals of various angles and positions of curvature were prepared by hand using either Mani Flexile Files, Mani SEC-O Files, Maillefer Flexofiles, or Zipperer Flexicut Files. After orifice enlargement, each file type was used to prepare 40 canals employing a balanced force motion and a modified double-flared technique. Pre- and postoperative images of the canals were taken with a videocamera, and stored and manipulated in a computer with image analysis software. The presence of canal aberrations and the amount of material removed as a result of preparation were determined from composite images of superimposed pre- and postoperative views. Significant differences (p < 0.001) in preparation time were observed, with Flexile Files being quickest and SEC-O Files being slowest. Overall, Flexofiles and Flexicut Files deformed significantly more (p < 0.001) than Flexile and SEC-O Files. The incidence of canal blockage was not influenced by instrument type, but...
The aim of this laboratory based study was to determine the shaping ability of Lightspeed nickel-... more The aim of this laboratory based study was to determine the shaping ability of Lightspeed nickel-titanium rotary instruments in simulated root canals. A total of 40 canals with four different shapes in terms of angle and position of curve were prepared with Lightspeed instruments using the stepback technique recommended by the manufacturer. This report describes the efficacy of the instruments in terms of prevalence of canal aberrations, the amount and direction of canal transportation, and overall postoperative shape. Preoperative and postoperative images of the canals were taken using a video camera attached to a computer with image analysis software. The preoperative and postoperative views were superimposed to highlight the amount and position of material removed during preparation. Only one (2.5%) zip and one elbow were created, with no ledges, perforations, danger zones, or blockages being produced. At specific points along the canal length there were highly significant differ...
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Papers by Paul Dummer