Comparative evaluation of stress distribution against the root canal wall at three different levels using novel NiTi rotary files - A finite element analysis.

Background: Recent innovations in the physical and mechanical features of endodontic file systems have diminished the prospect of stress generation and fracture risk in novel endodontic files. Aim: The purpose of this research was to comparatively evaluate the stress distribution of recently introduced endodontic rotary files with distinct features and metallurgy at three different levels of the root canal wall by finite element analysis. Materials and Methods: Forty endodontic files were used in this experiment after being inspected through a scanning electron microscope for any surface deformities. Based on their metallurgy and design, the scanned files were divided into four groups, each with 10 samples: Group A-2Shape files, Group B-F360, Group C-One Curve, and Group D-TruNatomy. To assess the mechanical behavior of these files, the stress produced by computer-aided models of these instruments on the dentinal wall of a simulated root canal was numerically analyzed using ANSYS® 15 Workbench finite element software. Results: A one-way ANOVA was used to assess all the raw data with post hoc Tukey analysis, the Shapiro-Wilk test, and Levene's test. F360 files exerted the maximum stress on the dentinal wall, while TruNatomy files exerted the least stress at all the distinct levels of dentinal walls. Conclusions: There was no statistically significant variation in the stress generated between the four groups. Therefore, it can be concluded that improvements in rotary file design and metallurgy have the potential to reduce the stress during canal shaping and the risk of instrument breakage during clinical use.

Comparative evaluation of canal transportation and canal centering ability in oval canals with newer nickel-titanium rotary single file systems - A cone-beam computed tomography study.

Context: The purpose of this study was to evaluate and compare the centering ability and canal transportation of TruNatomy, OneCurve, and Jizai file systems to assess their performance in oval-shaped canals using cone-beam computed tomography imaging. Materials and Methods: Forty-two fully formed single-rooted mandibular premolars were selected with a buccolingual canal size 2-2.5 times the mesiodistal size at 5 mm from the apex, with 0°-10° canal curvature with a 5-6 mm radius, at 5 mm from the apex. The teeth were divided into three groups (n = 14) and prepared with TruNatomy, OneCurve, and Jizai files based on the manufacturer's instructions. Cone-beam computed tomographic images were taken before and after instrumentation. The canal transportation and centering ability was calculated at 3, 6, and 9 mm from the apex in both mesiodistal and buccolingual directions. Statistical Analysis: Intergroup comparison was done using Kolmogorov-Smirnov test. Intragroup comparison was done using Freidman test. A comparison of categorical variables was done using the Chi-square test. Results: The results obtained did not present any statistically significant difference between the three groups, with TruNatomy and OneCurve showing relatively lesser canal transportation and better centering ratio when compared to the Jizai file system. Conclusions: It can, therefore, be concluded that all three systems used in the study are capable of safely preparing root canals with minimal errors.

A comparative evaluation of the effect of three different concentrations of in-office bleaching agents on microhardness and surface roughness of enamel - An in vitro study.

BACKGROUND: To evaluate the changes in the micro-hardness and surface roughness of enamel treated with three different concentrations of in-office bleaching agents. MATERIALS AND METHODS: In this in vitro study, 60 human incisors were divided into two groups (Group A and Group B). To obtain the baseline values, a Vickers tester was used to determine the surface microhardness in Group A, and a Surtronic tester was used for evaluation of surface roughness in Group B. Each group was then further subdivided into three subgroups and subjected to bleaching with Dash (Groups A1 and B1), Pola Office (Groups A2 and B2), and Opalescence Boost (Groups A3 and B3) containing 30%, 35%, and 40% hydrogen peroxide (HP), respectively. Samples were again subjected to testing to obtain the postbleaching values. Pre- and postbleaching data were analyzed by paired t-test. Intergroup comparison was carried out using one-way ANOVA (P ≤ 0.05). RESULTS: A significant decrease in microhardness values was observed following bleaching in all the three groups, with Group A1 showing maximum percentage decrease (2.58%), followed by Group A2 (1.23%) and Group A3 (0.73%). Furthermore, an increase in surface roughness was observed following bleaching, with Group B1 showing maximum percentage increase (14.80%), followed by Group B2 (8.25%) and Group B3 (5.79%). However, there was no significant difference in either microhardness or surface roughness when comparing the postbleaching values among the three bleaching agents. CONCLUSION: In-office bleaching agents may adversely affect the microhardness and roughness of enamel surface which are not related to the concentration of HP used.

Comparative evaluation of the effect of decontamination protocol on the shear bond strength of eighth generation bonding agent to contaminated dentin: an in vitro study.

INTRODUCTION: This in vitro study aims to evaluate and compare the effect of decontamination protocol - based on sodium hypochlorite - NaOCl, as a decontaminating agent, followed by the application of a collagen cross-linking agent like sodium ascorbate or Proanthocyanidin on the shear bond strength of eighth generation bonding agent to contaminated dentin (saliva, blood and blood followed by hemostatic agent). METHODS: The buccal surfaces of extracted premolars were flattened to expose the dentine. The teeth were then randomly divided into 3 groups based on the contaminant used (saliva, blood and blood followed by hemostatic agent). Decontamination protocol was carried out with sodium hypochlorite followed by application of either of the two collagen cross-linking agents (sodium ascorbate/proanthocyanidin) in each group. FuturaBond DC (eighth generation) bonding agent was used to bond composite to dentin surfaces which was subjected to shear bond strength testing. Data was analyzed by one-way ANOVA and Tukey test. RESULTS: All the groups (contaminated with saliva, blood, or hemostatic agent) showed a decrease in shear bond strength of composite resin to dentin. The shear bond strength of composite resin to dentin was least affected by contamination with saliva followed by contamination with blood and was most affected by contamination with a hemostatic agent.The decontamination protocol carried out showed that the combination of NaOCl and Proanthocyanidin improved the shear bond strength of composite to dentin significantly more than the combination of NaOCl and sodium ascorbate or of sodium hypochlorite used alone.

Comparative evaluation of push-out bond strength of gutta-percha using different sealers with lateral condensation and thermoplasticized obturation technique: An in vitro study.

AIM: The study aimed to evaluate and compare the push-out bond strength of gutta-percha using AH plus, Endosequence BC, and Roeko seal sealer with lateral condensation and thermoplasticized obturation technique. MATERIALS AND METHODS: Sixty single-rooted premolars were instrumented and samples were randomly assigned into three groups based on the sealer used (Group A-AH Plus, Group B-Endosequence BC, Group C-Roeko Seal) which were further divided into two subgroups-A1, B1, and C1 were obturated by the lateral condensation technique and A2, B2, and C2 using the thermoplasticized technique. Each sample was sectioned horizontally using a diamond disc, representing apical, middle, and coronal thirds, respectively. Root segments were then mounted on an acrylic block, and push-out bond strength of each sample was tested using the universal testing machine. STATISTICAL ANALYSIS: One-way ANOVA, Tukey's test, and unpaired t-test. RESULTS: For mandibular premolar teeth with a single canal using lateral condensation technique, the highest push-out bond strength was found in the A1 group (7.30 ± 0.61 MPa) at the apical level. While using the thermoplasticized technique, the highest push-out bond strength was found in the B2 group (3.71 ± 0.81 MPa) at the apical level. Overall results showed that the lateral condensation technique showed significantly higher push-out bond strength than thermoplasticized technique (P < 0.028). CONCLUSIONS: The push-out bond strength of AH Plus sealer was higher than the Endosequence BC sealer and Roeko seal sealer. Lateral condensation technique has shown higher push-out bond strength than the thermoplasticized technique.

Comparison of the incidence of postoperative pain after using a continuous rotary system, a reciprocating system, and a Self-Adjusting File system in single-visit endodontics: A prospective randomized clinical trial.

AIM: The aim of this study is to compare the incidence of postoperative pain using the ProTaper Next (PTN), WaveOne Gold (WOG), and Self-Adjusting File (SAF) systems. MATERIALS AND METHODS: Two hundred and fourteen patients with irreversible pulpitis were selected for single-visit endodontics. The teeth were blindly assigned to three groups based on the instrumentation system used: Group A (PTN), Group B (WOG), and Group C (SAF). Participants were asked to note the incidence of the pre- and postoperative pain on a visual analog scale at different time intervals. Paired t-test and one-way ANOVA were used along with post hoc Tukey's test. RESULTS: The greatest mean pain in Group A (PTN) and Group B (WOG) was found to be maximum in the first 24 h with a significant reduction in pain at the subsequent observation time points of 48 h, 72 h, and 7 days. Group C (SAF) showed minimum pain followed by Group B followed by Group A which showed comparatively higher pain scores even at the end of 7 days. CONCLUSIONS: In single-visit endodontics, SAF system may prove to be a better system compared with PTN and WOG as it produces minimal postoperative pain, thus improving the overall acceptance of endodontic treatment.

A comparative evaluation of accuracy of three electronic apex locators using histological section as gold standard: An ex vivo study.

INTRODUCTION: The aim of the present study was to comparatively evaluate the accuracy of iRoot, iPex II, and Propex pixi apex locator using histological sections as the gold standard. MATERIALS AND METHODS: Thirty patients indicated for extraction of single-rooted permanent teeth with single canal system were selected. Working lengths (WLs) of teeth were determined using iRoot, iPex II, and Propex pixi. Teeth were then extracted, and the files were reintroduced to the anatomic apex to measure anatomic canal length (ACL) and fixed at the ACL using flowable composite. The apical 4 mm of the roots were longitudinally shaved away to visualize the canal under a stereomicroscope at ×24 magnification. Digital photographs were evaluated to measure the distance between the major diameter and minor diameter. Thus, the WL, that is, the minor diameter length (MDL) was ascertained. RESULTS: Measurements of mean WLs within ±0.5 mm of minor diameter were 90% acceptable for iRoot, 86.66% for iPex II, and 80% for Propex pixi when compared with mean MDL as obtained from the histological sections. CONCLUSIONS: All apex locators have been shown to produce acceptable level of accuracy which clearly indicates their reliability in determining the WL.

Effectiveness of Various Endodontic Irrigants on the Micro-Hardness of the Root Canal Dentin: An in vitro Study.

INTRODUCTION: Irrigating solutions used for the elimination of micro-organisms during root canal preparation may affect the chemical and the physical properties of dentin thereby rendering the tooth more susceptible to fracture. Therefore careful and judicious selection of irrigant is required which have maximum benefits with minimum undesirable properties. AIM: The aim of the present study was to evaluate the effect of various endodontic irrigants on the micro-hardness of the root canal dentin. MATERIALS AND METHODS: This in vitro study was carried out on eighty freshly extracted mandibular premolars with single canals. They were decoronated at the cemento-enamel junction. Roots were sectioned longitudinally into two halves. They were then polished and placed in autopolymerised resin moulds with the polished surface facing outside. The samples were divided into four groups based on the irrigants in which they were immersed i.e., 3% Sodium Hypochlorite (3% NaOCl), 17% Ethylene Dioxide Tetra Acetic Acid (17% EDTA), 0.2% Chitosan and 6% Morindacitrifolia Juice (MCJ) for 15 minutes each. All the specimens were then subjected to micro-hardness testing using a Vickers micro-hardness tester. Statistical analysis was done using one way Analysis of Variance (ANOVA), Post-Hoc Tukey test and Paired t-test to compare the pre and post immersion micro-hardness values of the selected samples. RESULTS: The results of the present study indicated that 17% EDTA and 0.2% Chitosan, significantly decreased the micro-hardness of root dentin whereas 6% MCJ and 3% NaOCl had no significant effect on the microhardness before and after immersing in the irrigants. CONCLUSION: A 6% MCJ and 3% NaOCl which have significant antibacterial, antifungal, anti-inflammatory and smear layer removing properties showed negligible effect on the micro-hardness of root canal dentin making them suitable endodontic irrigating solution.

Evaluation of Correlation between Salivary Calcium, Alkaline Phosphatase and Osteoporosis- A Prospective, Comparative and Observational Study.

INTRODUCTION: Fixed and/or removable prosthodontics caters to the restorative needs of the largest count of geriatric patients whose rehabilitative procedures depend on the quality and quantity of available bone. The common diagnostic parameters for quantifying bone may involve an invasive blood examination, an expensive bone densitometry procedure or a urine analysis. Sialometry involving the basic biochemistry of saliva analysis may be proposed as an alternative to the conventional investigative protocol and its usefulness may be attributed owing to its non invasive and simpler procedure. AIM: The aim of this study was to compare the salivary calcium and alkaline phosphatase among osteoporotic, osteopenic and normal edentulous subjects. MATERIALS AND METHODS: A prospective, comparative and observational study was carried out on 80 selected edentulous subjects (40 males and 40 females) aged 55-75 years (30 osteoporotic, 30 osteopenic and 20 control). A sample of saliva was taken for the study. Salivary calcium was measured by Arsenazo reaction; and alkaline phosphatase by the International Federation of Clinical Chemistry (IFCC) method. Statistical analysis was done by unpaired t-test. A comparison was made in the levels of salivary calcium and alkaline phosphatase with that of osteoporosis and osteopenia. RESULTS: The mean salivary calcium and alkaline phosphatase levels were found to be significantly higher in the osteoporotic and osteopenic edentulous subjects as compared to the control group. CONCLUSION: Salivary calcium and alkaline phosphatase are increased significantly in case of osteoporosis and osteopenia. Hence, screening of salivary samples of patients may be an effective indicator for the detection of underlying disorders of bone metabolism.

Comparative antimicrobial efficacy of selected root canal irrigants on commonly isolated microorganisms in endodontic infection.

OBJECTIVE: This study aims to evaluate and compare the antimicrobial efficacy of three selected root canal irrigants (BioPure MTAD, metronidazole, aztreonam) against microbes commonly isolated from polymicrobial microbiota of root canal infection. MATERIALS AND METHODS: This study was designed with four experimental groups (Group I - Bacteroides fragilis, Group II - Propionibacterium acnes, Group III - Enterococcus faecalis, Group IV - Candida albicans) based on the microbes selected for the study. Group I and Group II bacteria were used to compare and evaluate antimicrobial effect of BioPure MTAD, metronidazole, aztreonam, and normal saline. Group III and Group IV bacteria were used to compare and evaluate antimicrobial efficacy of BioPure MTAD, aztreonam, and normal saline. Normal saline was used as a control irrigant in this study. Agar disc diffusion method was applied to assess and compare the antimicrobial action of selected irrigants. RESULTS: Metronidazole was found to be the most effective root canal irrigant against B. fragilis and P. acnes among the tested irrigants. Mean zone of inhibition against E. faecalis has been shown to be maximum by BioPure MTAD, followed by aztreonam. Antifungal effect against C. albicans was only shown by BioPure MTAD. CONCLUSIONS: Overall, BioPure MTAD is the most effective root canal irrigant as it has shown an antibacterial effect against all the tested microorganisms. However, metronidazole showed maximum antibacterial effect against obligate anaerobes. Aztreonam also showed an antibacterial effect in the present study, raising its possibility to be used as a root canal irrigant in the future.

Perception of Acceptable Range of Smiles by Specialists, General Dentists and Lay Persons and Evaluation of Different Aesthetic Paradigms.

INTRODUCTION: One of the most important goals of restorative dentistry is to restore the patient's aesthetic. Smile analysis is subjective and it differs from person to person. An aesthetic smile involves a harmonious relationship between various parameters including the hard and soft tissues. AIM: The aim of the study was to identify the acceptable range of several smiles (alone and in conjunction with the face) by specialists, general dentists as well as lay persons; and to identify the values of different criteria i.e., the Golden Proportion (GP), the Recurrent Esthetic Dental proportion (RED), Width to Height ratio (W/H ratio), the Apparent Contact Dimension (ACD), and lateral incisor position in a smile. MATERIALS AND METHODS: Hundred photographs of 50 subjects were taken, 50 of the smile alone and 50 of the individual's frontal view of face. The photographs of the smiles and the faces were assessed for the aesthetic acceptability by 30 evaluators including 10 specialists with advanced training, 10 general dentists and 10 lay persons. Irreversible hydrocolloid impressions were made of the dentitions of all the individuals using stock trays and were poured in dental stone. Measurements were made on the facial surface of the teeth on the models and were recorded in millimeters using a sharp tipped digital vernier calliper. Data was analyzed to evaluate the presence of different parameters assessed in the smiles. Mean and standard deviation values for the percentage of only the agreeable smiles were calculated in both individual smile analysis and in conjunction with the face. The non agreeable smiles were excluded from further statistical analysis. Pearson Correlation Coefficient was calculated to compare the values obtained in all the three groups. RESULTS: More number of smiles were considered agreeable by the general dentists when compared to the specialists and the number even increased in case of evaluation by lay persons. Greater number of smiles was found to be agreeable when they were evaluated in conjunction with the face. CONCLUSION: Rather than assessment of individual numeric parameter that defines an ideal aesthetic smile, a smile to be aesthetic should harmonize with the composition of the face.

Evaluation of the incidence of microcracks caused by Mtwo and ProTaper Next rotary file systems versus the self-adjusting file: A scanning electron microscopic study.

INTRODUCTION: To evaluate the incidence of microcrack formation canal preparation with two rotary nickel-titanium systems Mtwo and ProTaper Next along with the self-adjusting file system. MATERIALS AND METHODS: One hundred and twenty mandibular premolar teeth were selected. Standardized access cavities were prepared and the canals were manually prepared up to size 20 after coronal preflaring. The teeth were divided into three experimental groups and one control group (n = 30). Group 1: The canals were prepared using Mtwo rotary files. Group 2: The canals were prepared with ProTaper Next files. Group 3: The canals were prepared with self-adjusting files. Group 4: The canals were unprepared and used as a control. The roots were sectioned horizontally 3, 6, and 9 mm from the apex and examined under a scanning electron microscope to check for the presence of microcracks. The Pearson's Chi-square test was applied. RESULTS: The highest incidence of microcracks were associated with the ProTaper Next group, 80% (P = 0.00), followed by the Mtwo group, 70% (P = 0.000), and the least number of microcracks was noted in the self-adjusting file group, 10% (P = 0.068). No significant difference was found between the ProTaper Next and Mtwo groups (P = 0.368) while a significant difference was observed between the ProTaper Next and self-adjusting file groups (P = 0.000) as well as the Mtwo and self-adjusting file groups (P = 0.000). CONCLUSION: All nickel-titanium rotary instrument systems were associated with microcracks. However, the self-adjusting file system had significantly fewer microcracks when compared with the Mtwo and ProTaper Next.

Unmasking the Effect of Analgesics on Endodontic Diagnosis Using a Novel Bite Force Sensor Device: A Prospective, Randomized Clinical Trial.

INTRODUCTION: A definitive diagnosis is of primary importance before initiating any endodontic treatment; yet, there are occasions when the dental professional is unable to accurately reproduce the patient's chief complaint, as it can pose a dilemma and may require consideration of multiple variables in order to reach an accurate diagnosis. So to overcome this problem, a methodical approach in providing endodontic treatment should be implemented which includes diagnosis, definitive dental treatment and adjunctive drug therapy, known as the "3D" strategy. AIM: The purpose of this study was to evaluate the possible "masking" effect of these analgesics on endodontic diagnosis using a novel bite force sensor device. MATERIALS AND METHODS: A total of 90 patients with endodontic pain were selected and they were given either a placebo or 400 mg ibuprofen (brufen) or 50mg diclofenac sodium (voveron). Both patients and operators were completely blinded to the drugs administered. Bite force tolerance values were noted before and one hour after administration of medication using the self designed bite force sensor. RESULTS: The pre- and post-bite force tolerance values were tabulated for both contralateral and affected tooth. For the affected tooth, there was statistically significant difference between pre- and post-bite force tolerance values in Group I (i.e., ibuprofen) and Group II (i.e., diclofenac sodium) (p<0.05) with no significant difference observed in Group III (placebo). CONCLUSION: The easily available over the counter self administered analgesics in addition to providing symptomatic relief to patients suffering from symptomatic apical periodontitis may also cloud the definitive diagnosis of the clinician, thus jeopardising the treatment plan. The self designed bite force sensor was effective in arriving at a definitive diagnosis in teeth with chronic irreversible pulpitis with symptomatic apical periodontitis, where the allodynia has been camouflaged by the use of analgesics like ibuprofen and diclofenac sodium.

Effect of Oral Premedication on the Efficacy of Inferior Alveolar Nerve Block in Patients with Symptomatic Irreversible Pulpitis: A Prospective, Double-Blind, Randomized Controlled Clinical Trial.

INTRODUCTION: It is generally accepted that achieving complete anaesthesia with an Inferior Alveolar Nerve Block (IANB) in mandibular molars with symptomatic irreversible pulpitis is more challenging than for other teeth. Therefore, administration of Non-Steroidal Anti-Inflammatory Agents (NSAIDs) 1 hour prior to anaesthetic administration has been proposed as a means to increase the efficacy of the IANB in such patients. AIM: The purpose of this prospective, double-blind, randomized clinical trial was to determine the effect of administration of oral premedication with ketorolac (KETO) and diclofenac potassium (DP) on the efficacy of IANB in patients with irreversible pulpitis. MATERIALS AND METHODS: One hundred and fifty patients with irreversible pulpitis were evaluated preoperatively for pain using Heft Parker visual analogue scale, after which they were randomly divided into three groups. The subjects received identical tablets of ketorolac, diclofenac pottasium or cellulose powder (placebo), 1 hour prior to administration of IANB with 2% lidocaine containing 1:200 000 epinephrine. Lip numbness as well as positive and negative responses to cold test were ascertained. Additionally pain score of each patient was recorded during cavity preparation and root canal instrumentation. Success was defined as the absence of pain or mild pain based on the visual analog scale readings. The data was analysed using One-Way Anova, Post-Hoc Tukey pair wise, Paired T - Test and chi-square test. Trial Registery Number is 4722/2015 for this clinical trial study. RESULTS: There were no significant differences with respect to age (p =0.098), gender (p = 0.801) and pre-VAS score (DP-KETO p=0.645, PLAC-KETO p =0.964, PLAC-DP p = 0.801) between the three groups. All patients had subjective lip anaesthesia with the IAN blocks. Patients of all the three groups reported a significant decrease in active pain after local anaesthesia (p< 0.05). The post injection VAS Score was least in group 1 (KETO) followed by group II (DP) & maximum in group III (PLACEBO). CONCLUSION: Oral pre-medication with 10 mg KETO resulted in significantly higher percentage of successful inferior alveolar block in patients with irreversible pulpitis than pre-medication with 50 mg DP & PLAC.

An in vitro evaluation of antimicrobial activity of five herbal extracts and comparison of their activity with 2.5% sodium hypochlorite against Enterococcus faecalis.

CONTEXT: Sodium hypochlorite is the most widely used irrigant in endodontic practice, but it has various disadvantages. Literature has shown that herbal products such as Propolis, Azadirachta indica (AI), Triphala, Curcuma longa, and Morinda citrifolia (MC) possess good antimicrobial properties and thus can be used as potential endodontic irrigants. AIM: To evaluate and compare the antimicrobial activity of five herbal extracts, i.e., Propolis, AI, Triphala, C. longa, and MC with that of 2.5% sodium hypochlorite against Enterococcus faecalis. MATERIALS AND METHODS: E. faecalis American Type Culture Collection 21292 was inoculated onto brain heart infusion agar plate. Discs impregnated with herbal medicaments were placed on the inoculated plates and incubated at 37°C aerobically for 24 h and growth inhibition zones were measured. STATISTICAL ANALYSIS: Mean zone of inhibition in descending order was found as sodium hypochlorite > Propolis > AI > Triphala > C. longa = MC > ethanol. Statistical analysis was performed using one-way analysis of variance which showed a significant difference in the zone of inhibition of sodium hypochlorite and Propolis (P < 0.001). RESULTS: Propolis showed highest zone of inhibition among all the herbal extracts next to sodium hypochlorite. CONCLUSION: Propolis and AI have significant antimicrobial activity against E. faecalis.