Diamond Disc Research Articles

An in-vitro comparative evaluation for detection of residual gutta-percha after root canal retreatment with four different files using stereo microscope

Background: Removal of gutta-percha using hand files with or without solvent is tedious and time consuming process especially when the root filling material is well compacted8. Therefore, the use of NiTi rotary instruments in the root canal retreatment might decrease patient and operator fatigue and various studies have reported their efficacy, cleaning ability and safety. Several NiTi rotary instruments also were been used to remove gutta-percha. Here in this study four file systems were used to assess the efficacy of each file system in retreatment procedures.Materials & methods: The study samples comprised of 80 extracted anteriors having single root canals with fully formed apices were collected. The crowns were de-coronated with a diamond disc to leave a 16-mm root. A size 10 K-file was introduced into the canal until it was visible at the apical foramen. The working length was determined by subtracting 1mm from this measurement. During shaping, each canal was irrigated with 3% sodium hypochlorite then smear layer was removed with 17% EDTA and 1 ml of 3% sodium hypochlorite. After one month the teeth were divided into following groups with 20 specimens each as follows.

Effectiveness of three different rotary systems in removing gutta percha from root canals

Background: The present study was conducted for comparing the effectiveness of three different Rotary systems in removing gutta percha from root canals. Materials & methods: 30 single rooted freshly extracted, mandibular premolars were collected and stored in 10% formalin until further use. Crowns of selected teeth were decoronated using diamond disc to standardize the working length to 16 mm for each specimen. Access preparation was done on each tooth and a size 10 K-type file was inserted into the canal until it was visible at the apical foramen to ensure that the canal was patent. Afterwards, all the specimens were randomly divided into three study groups according to type of retreatment system. Group A: ProTaper Universal retreatment Ni–Ti rotary instrumentation system, Group B: Mtwo retreatment Ni–Ti rotary instrumentation system, and Group C: R-Endo Ni–Ti rotary instrumentation system. After tooth splitting, each half of every specimen was separately imaged. Digitized images of each third of the root canal of each half of every specimen were obtained and evaluated.

Comparative evaluation of the fracture resistance of reattched fragments using three different retentive methods: An in vitro study

: Traumatic injuries to the anterior teeth are one of the most difficult and perplexing problems faced in the paediatric dentistry. Coronal fracture of the anterior teeth is a common form of dental trauma that mainly affects the maxillary and mandibular incisors. Fragment reattachment has been the preffered technique among clinicians because it has several advantages over the composite restorations such as it is a conservative procedure, maintains original tooth contours, translucence and incisal edge wears at similar rate to adjacent teeth.: To compare and evaluate the fracture resistance of reattached fragments using three different methods.Forty sound permanent mandibular central and lateral incisor were selected and mounted in self-cure acrylic resin. The teeth were sectioned with a diamond disc 3mm short of the incisal edge and they were randomly divided into four groups (n=10). Group I – simple reattachment, group II- internal dentinal groove, group III – vertical groove with fiber reinforced post placement, group IV – overcontouring done before the reattachment procedure. The force required to fracture the specimen were recorded using an onscreen calibration tool of the universal testing machine. The results were statistically analyzed.: The results showed that group I, group II and group IV required lesser force to fracture when compared with group III.: The group restored with fiber reinforced post showed the highest value of fracture strength while the simple reattachment had the lowest value.

Evaluation of the microleakage in class II cavities restored with composite resin by using different placement techniques and light cure units– An in vitro study

The aim of the present study is to evaluatepost thermocycling microleakage scores in class II cavities restored with Tetetric n ceram (TC) by, Bulk fill technique, Incremental technique, Centripetal techniques, followed by polymerization light source QTH and LED.ethodsClass II Conventional Mesioocclusal (MO) cavities were prepared with occlusal gingival depth 1mm above the CEJ. The final preparation has the following dimensions, 3 mm – buccolingual extension1.5 mm –axial dept hand 4 mm –occluso-cervical extension. The samples will be etched and rinsed, and then the universal matrix will be placed after that the bonding agent will be applied and curedLater all specimens were randomly divided into three groups, each containing 20 teeth.GROUP I-Bulk Technique, GROUPII- Incremental Technique with oblique laying GROUP III-Specimens were stored in distilled water at 37C till it is subjected to thermocycling. Sthermo cycled for 500 cycles at with temperature range of 5 to 55 degrees with 20 seconds dwell time. Specimens were sectioned along the long axis in the mesiodistal direction of the restoration with a diamond disc and analyzed using a stereo microscope at 10x magnification by an independent examiner who was blinded by the groups.Comparison of three groups with microleakage scores at gingival margins by Kruskal Wallis one-way ANOVA test. Pair-wise comparison of all groups with respect to microleakage scores at gingival margins by Mann-Whitney U test. Statistical analysis was performed using SPSS STATISTICS 21.0 software.Among the three experimental groups least microleakage was seen with subgroup IIA (IN-QTH) followed by subgroup IIIA (CE-QTH) followed by subgroup IA (B-QTH).Among all these groups and subgroups, the least microleakage is seen in IN-LED (subgroup IIB), highest microleakage is seen in B-QTH (subgroup IA), interestingly there is no statistical difference between IN-QTH (subgroup IIA) and CE-LED (sub group IIIB).

Assessment of Root Dentin Defect during Retreatment Procedure using Various NiTi Hand and Rotary Retreatment Files

Aim:The aim of the current study was to evaluate the radicular dentin defect during retreatment employed diverse NiTi hand and rotary retreatment file systems.Materials and Methods:Eighty mandibular premolars with a single root and root canal that were recently extracted were gathered and stored. The premolars were subject to decoronation at cementoenamel junction (CEJ) beneath irrigation with water to attain a uniform radicular length of 16 mm. Gutta-percha cones were covered with sealer and introduced into the root canal up to the working length. Eighty teeth were allocated at random into four groups with each group consisting of 20 samples. Group I: Control, Group II: EdgeFile XR retreatment rotary files, Group III: ProTaper Universal retreatment files, and Group IV: MTwo retreatment files. Under constant water cooling, the roots were cut flat with a diamond disc at apical third (3 mm), middle third (6 mm), and cervical third (9 mm) points. Stereomicroscope was employed to visualize the sections below × 20 magnification.Results:A statistically significant difference was noted among the groups with respect to the formation of radicular dentinal defects at 3 mm (P < 0.01) and 6 mm (P < 0.001), while the sections at 9 mm did not exhibit any statistically significant difference (P > 0.598).Conclusion:Despite the limitations in this study, it was concluded that all the evaluated file systems efficiently eliminated root canal filling during the retreatment. In addition, it was noted that the EdgeFile XR group exhibited fewer root dentin defects in comparison with the MTwo and ProTaper Universal group of files.

Assessment of the Efficacy of Different Desensitizing Agents on Dentinal Tubules Occlusion- An In vitro Study.

Aim:The aim of the current research was to evaluate the effectiveness of three desensitizing agents on the occlusion of dentinal tubules.Materials and Methods:Eighty human maxillary and mandibular permanent premolar teeth that were subjected to extraction in the course of orthodontic treatment were utilized in this study. The teeth were subjected to sectioning by employing a double-sided diamond disk. A block was procured from every even cervical dentinal surface with dimensions of 4 mm × 4 mm × 3 mm (L × B × H) by sectioning the tooth transversely. Further, 35% phosphoric acid was utilized for 30 s to cause dentinal etching, thereby exposing the dentinal tubules. The blocks of dentin were assigned at random to one of the following four groups (n = 20): group I: control, group II: bioactive glass containing desensitizing agent, group III: 1% nano-hydroxyapatite containing desensitizing agent, group IV: tri-calcium phosphate-containing desensitizing agent. The exterior of the specimens was scanned and evaluated using a scanning electron microscope.Results:1% nano-hydroxyapatite-containing desensitizing agent (2.04 ± 0.08) exhibited higher mean dentinal tubular blockage, followed by the bioactive class-containing desensitizing substance (2.26 ± 0.19), tri-calcium phosphate desensitizing agent (2.84 ± 0.10), and the control group (4.18 ± 0.12) in that order. Amid the experimental groups employing the various desensitizing substances, there were significant differences statistically with P < 0.001.Conclusion:The current research concluded that each of the three desensitizing agents was efficient in dentinal tubular occlusion regardless of their different chemical constitution. However, it was noted that 1% nano-hydroxyapatite-containing desensitizing agent was marginally superior to the bioactive glass- and tri-calcium phosphate-containing desensitizing agents.

Silver nanoparticles penetration in dentin: Implications for long-term caries arrestment

The effectiveness of silver nanoparticles (AgNPs) as a caries arrestment agent was demonstrated in clinical trials some years ago; however, the mechanisms underlying their action remain unclear. It was hypothesized that the AgNPs could penetrate the dentinal tubules, contributing to their enduring cariostatic activity. The experiments were carried out with teeth samples with the incisal coronal third removed with a rotating diamond disk, exposing the dentin beneath the enamel to simulate shallow occlusal caries lesions. The dentin surfaces were treated with two different AgNP colloids: (i) spherical nanoparticles (7.5 nm) and (ii) a mixture of spherical (24.3 nm), triangular (33.8 nm), and rod-shaped (40.1/18.8 nm) nanoparticles. The samples were analyzed by scanning electron microscopy (SEM) and focused-ion beam SEM (FIB-SEM), allowing for the observation of the inner areas of the dentin. It was observed that AgNPs are able to penetrate dentinal tubules and adhere to their walls. The depth depends on the exposure time of the dentin surface to the colloid and the average nanoparticle size. The smaller the nanoparticles and the longer the exposure time, the deeper their penetration. At maximum, the AgNPs were detected up to 362.1 µm from the surface. The total silver amount in the sub-surface intra-tubular dentin was estimated to be within the concentration range expected to inhibit bacterial growth. The maximum penetration depth detected is shallow enough to avoid AgNP contact with the dental pulp.

Evaluation of Fracture Resistance of Reattached Fractured Tooth Fragment Stored in Different Storage Media: An In Vitro Study

To evaluate the fracture resistance of coronal fractured tooth fragments stored in five different storage media when reattached with nanohybrid flowable composite. The crown portion of 50 extracted human permanent maxillary central incisors were divided into three equal parts (incisal third, middle third and cervical third) and then marked incisal third were cut with the diamond disk. These were divided into five equal groups according to the type of storage media used i.e. dry storage, fresh tender coconut water, HBSS, milk, and propolis for 2 hours. Coronal fractured part with their respective apical parts were then reattached with flowable composite (G-aenial Universal Flo, GC India), then after thermocycling process samples were subjected to universal testing machine for testing fracture resistance. The collected data were subjected to statistical analysis using one way ANOVA and Post-hoc Tukey test. The obtained results revealed that large amount of force is required to fracture the reattached teeth which were stored in milk and fresh tender coconut water as compared to those which were stored in dry environment, HBSS and propolis. In this study, maximum fracture resistance was seen in teeth stored in milk and fresh tender coconut water. Therefore, these two were considered as better storage media. Due to increased interest towards the use of tooth colored restoration, recently, fractured teeth reattachment treatment procedure gaining attention by preserving life like translucency of treated tooth.

Comparative evaluation of fracture strength recovery of anterior tooth fragment reattachment using different methods and bonding systems: An in vitro study

PurposeTo compare and evaluate the fracture strength recovery of fractured teeth using the combination of reattachment techniques (simple reattachment, over contour and internal dentinal groove) and bonding adhesives (Super-Bond C & B and Calibra Universal). Materials and methodsSeventy human central incisors gathered from dental clinics in Ranchi and Hazaribag, Jharkhand, India, were randomly divided into 3 groups (G-I to G-III); G-I (n = 10) being the control group, only the test groups G-II and G-III (n = 30 each) were fractured using diamond disc and bonded with Super-Bond C & B and Calibra Universal respectively. These two groups were further sub-grouped into 3 each based on the reattachment techniques used. Post reattachment, the specimens were tested for fracture strength recovery and the data obtained was evaluated using One-way Analysis of Variance (ANOVA) and multiple comparison tests. ResultsThere was statistically significant difference of fracture strength recovery between control (G-I) and the experimental groups (G-II and G-III), P<0.0001. Comparison between the experimental groups revealed the fractured teeth reattached with Super Bond C&B showed highest fracture strength recovery compared to Calibra Universal. Among the different preparation techniques applied, the over contour technique combined with Super-Bond C & B showed the maximum fracture strength recovery attaining 92% fracture resistance as that of the control specimens. ConclusionThough none of the combinations of adhesives and techniques have achieved the fracture strength recovery as that of the intact teeth, Super-Bond C & B showed better performance compared with Calibra Universal in combination with the techniques used in the current study. Further, Super-Bond C & B combined with over contour technique showed the highest fracture strength recovery.

Diagnostic Validity in Occlusal Caries Detection of ICDAS II, DIAGNOdent, Radiography and a Combination of the Three Methods: An In Vitro Study.

In this study, we compare the efficacy and diagnostic concordance of the ICDAS, the radiographic criterion and the instrument known as the DIAGNOdent fluorescence laser pen on occlusal caries lesions using a histological section as the gold standard. Of 100 teeth that did not present cavitated occlusal lesions or occlusal fillings, 80 were chosen through a randomization program and examined by two previously trained and calibrated researchers. Subsequently, the teeth were sectioned with a diamond disk and observed under an optical microscope. The results were studied for caries with a limit established in enamel and caries with extension to dentin. The intra-examiner (0.821–0.933) and inter-examiner (0.817–0.924) reproducibility obtained for both ICDAS and DIAGNOdent for the diagnosis of borderline enamel caries was high. Similarly, intra-examiner (0.686–1.000) and inter-examiner (0.809–0.944) reproducibility for diagnosis of caries with dentin extension was also high for both methods. The sensitivity obtained was 0.76 (ICDAS), 0.87 (DIAGNOdent) and 0.58 (Rx), whereas the specificity obtained was 0.66 (ICDAS), 0.4 (DIAGNOdent) and 0.77 (Rx) for lesions limited to enamel. For lesions with extension to dentin, the sensitivity obtained was 0.73 (ICDAS), 0.82 (DIAGNOdent) and 0.09 (Rx), and the specificity obtained was 0.79 (ICDAS), 0.52 (DIAGNOdent) and 0.97 (Rx). Sensitivity increases in both cases by combining diagnostic methods. In conclusion, ICDAS and DIAGNOdent are better diagnostic methods than Rx for the detection of occlusal caries, and the combination of these methods helps to obtain a better diagnosis.

The Effect of Different Abrasives on the Shear Bond Strength of Adhesive Resin Cements to Dentin

Aim: The aim of this study was to evaluate the influence of dentin surface preparation with coarse diamond, extra-fine diamond, and polishing discs on the shear bond strength (SBS) of two resin cements (RCs) to dentin. Materials and Methods: Sixty-six recently extracted human mandibular third molar teeth that were free of cracks, caries, or restorations were collected. Sixty teeth were used for the SBS test. The occlusal part of the crowns was cut to expose mid-coronal dentin. The teeth were divided into three dentin preparation groups: coarse diamond (Meisinger, Germany), extra-fine diamond, and polishing discs (SofLex, 3MESPE, USA), and further conventional RC combined with a self-etch adhesive (Panavia F2.0/ED Primer II, Kuraray, Japan) or self-adhesive RC (Maxcem Elite, Kerr, USA) subgroups ( n = 10). Sixty composite resin blocks were prepared (diameter: 3 mm, height: 4 mm) and bonded to the teeth according to the groups. The SBS test was performed with a universal testing device. Six teeth were used for the observation of prepared dentin surfaces and the resin–cement dentin interfaces using field emission scanning electron microscopy (Mira 3 XMU, Tescan). Statistical analyses were performed using the Mann–Whitney U and Kruskal–Wallis tests ( P &lt; .05). Results: Panavia F2.0/ED Primer II exhibited significantly higher SBS values for coarse and extra-fine diamond than for the polishing discs ( P &lt;.05). Regarding Maxcem Elite, no significant difference was observed for the preparation methods ( P &gt; .05). Panavia F2.0/ED Primer II had higher bond strength than Maxcem Elite for the dentin surface prepared with the coarse diamond ( P &lt;.05). The differences were not significant for the extra-fine diamond and the polishing disc groups ( P &gt; .05). Conclusion: The use of polishing discs did not increase the SBS of the RCs to the dentin.

Confocal laser scanning microscopic evaluation of sealing ability of bone cement, mineral trioxide aggregate and biodentine as root-end filling materials

Aim: To compare the sealing ability of polymethylmethacrylate (PMMA) bone cement, mineral trioxide aggregate (MTA), and Biodentine as root-end filling materials by assessing the degree of microleakage through confocal laser scanning microscopy. Materials and Methods: Thirty extracted maxillary incisors were root canal treated using the rotary ProTaper system. Apical root resections followed by retrograde cavity preparation were done. The teeth were divided into three groups and filled with the 3 tested materials (PMMA bone cement, MTA, and Biodentine). Samples were coated with nail varnish, immersed in 0.5% aqueous solution of rhodamine B dye for 24 h, and rinsed with water to remove excess dye. Samples were horizontally sectioned at 1 mm intervals into three using a diamond disk and were labeled A, B, and C and considered first, second, and third, respectively, based on their distance from the apex. Each slice was divided into four equal parts and evaluated using a confocal laser scanning microscope. Dye penetration was scored based on the amount of microleakage. The data were analyzed using one-way analysis of variance. Results: Intergroup comparison of the mean scores of dye penetration among the three materials showed that there is a statistical difference between PMMA bone cement, MTA, and Biodentine, in sections B and C (P ≤ 0.05). The three groups showed no statistical difference in dye penetration scores in section A. Conclusion: The microleakage is least with PMMA bone cement followed by Biodentine and MTA. Microleakage was least in section C followed by sections B and A.

Frequency of MB2 in maxillary first and second molars in Gujarati population

Aim: The aim of this study was to investigate the frequency of second mesiobuccal canal in maxillary first and second molars. Materials and Methods: Maxillary fifty first molars and fifty second molars were collected and embedded into plaster blocks. The teeth were photographed digitally from the occlusal aspect using a stereomicroscope under standard (×8) magnification. The occlusal portions of crowns were then sectioned at cement–enamel junction with slow-speed diamond disk. To gain straight line visibility, overhung dentin over the canal orifices was removed with safe-tip diamond bur. Once again, the teeth were photographed from their occlusal aspect under the same magnification and exposure conditions. Results: MB2 canals were detected 76% and 64% in first and second molars, respectively.

Retrievability of Odontopaste and Metapex With 17% Ethylenediaminetetraacetic Acid and 10% Maleic Acid From Root Canals: An Invitro Study.

AimTo evaluate the efficacy of 10% maleic acid in comparison with 17% ethylenediaminetetraacetic acid (EDTA) in the removal of intracanal medicaments from the root canal system.Materials and methodsForty-eight extracted single-rooted mandibular premolars were decoronated to standardize the length of 14 mm. Chemomechanical preparation was done using the crown-down technique with Protaper files (Dentsply‑Maillefer, Ballaigues, Switzerland) till F4, followed by irrigation with 2 ml of 5.25% sodium hypochlorite (NaOCl) after each instrument, and 5 ml of 17% EDTA was used as the final irrigating agent.Metapex (Meta Dental Corp. Ltd., Elmhurst, NY, USA) and Odontopaste (Australian Dental Manufacturing, Kenmore Hills, Qld, Australia) were the two intracanal medicaments that were used in this study.Total samples were divided into two groups based on the intracanal medicament that was placed in the canal. In group 1, Metapex was injected into the root canal until the material extruded through the apex. In group 2, Odontopaste was placed into the canal until the material extruded through the root apex. Cleaning off the excess medicament was done with a moist cotton pellet. After temporary sealing with a cotton pellet and Cavit, all the samples were stored at 37 ºC and 100% relative humidity for a period of seven days. The teeth in each group were further randomly divided into three subgroups on the basis of the irrigant used for retrieval of medicament. In groups 1A and 2A, 1ml of 17% EDTA was used; in groups 1B and 2B, 1ml of 10% maleic acid was used; in groups 1C and 2C, 1ml of 0.9% saline was used. Sonic agitation for 1 minute, followed by a final rinse of 1 ml distilled water, was used in all the groups.After the intracanal medicament was removed from the canal, the roots were longitudinally sectioned using a diamond disk (Bego, Berman, Germany). The residual medicament on each section was evaluated under a stereomicroscope (×30; Medilux, MDL-DS4-BI, Biosystems, Curitiba, PR, Brazil). The data were analyzed using SPSS version 23.0 software (IBM Corp., Armonk, NY). Kruskal-Wallis ANOVA and Mann-Whitney U test (post hoc) were applied for intergroup comparisons. A Wilcoxon signed-rank test was applied for intragroup comparisons.ResultsBoth the chelators, 17% EDTA and 10% maleic acid, removed the Odontopaste significantly better than Metapex. However, 17% EDTA was more effective in the removal of Odontopaste. 10% Maleic acid showed better results in the removal of Metapex than 17% EDTA.ConclusionNone of the chelating agents was able to totally retrieve the intracanal medicaments. When compared to Metapex, Odontopaste showed significantly better retrievability from the root canal with both 17% EDTA and 10% Maleic acid, whereas the retrievability of Metapex was significantly better with 10% Maleic acid in comparison to 17% EDTA.

ASPECTS REGARDING THE CUTTING CAPACITY OF DIAMOND DISCS USED IN THE FLAT GRINDING OF HARD GRANITE AND BASALT MINERAL MATERIALS

The paper presents how to determine the partial and global cutting capacity (CC) based on technological evaluation criteria (sustainability, specific energy consumption, cutting forces, roughness) and technical economic criteria (grinding productivity and cost). The theoretical-experimental model that allows the determination of the global CC for diamond discs takes into account the specific features of these super abrasive tools and the cutting process for flat grinding of hard mineral materials granite and basalt. Also, are presented the characteristics of diamond discs, the experimental stand and the factorial plans used in the experimental part.

Comparative Evaluation Of Push Out Bond Strength Of Endosequence Bc Sealer As Against Mta Plus Sealers When Used With Different Obturation Techniques

New technologies have led to the concept of recent bioactive dental materials, which makes the majority of today’s dentists to produce substantial endodontic results. The introduction of advanced material science made tremendous changes in the dental practice. Aim and Objectives : Aim of this study was to assess and compare the push-out bond strength of Endosequence Root Repair Material (ERRM putty), White Mineral trioxide aggregate (WMTA) and Biodentine after incubation in phosphate buffered saline (PBS) for 7 days, 30 days and 45 days. Materials and methods : 90 extracted single rooted human premolar teeth were used in this study. To avoid the desiccation of teeth after extraction, the teeth were kept in hydrogen peroxide solution and washed under tap water. Then the teeth were cleaned with pumice and stored in normal saline at 37˚C until use. The middle 1/3rd portion of each root was sectioned at right angle to the long axis to produce discs of 2.00 ± 0.05 mm thickness using a diamond disc with continuous water irrigation. Finally, 90 root slices were produced. The specimens were dipped in 17% EDTA for 3 min followed by 3 % NaOCl for the same period of time and then rinsed with distilled water and dried. The specimens were divided randomly into 3 groups: Group I- ERRM, Group II - White MTA, Group III- Biodentine. PBS solution was changed every 5 days to replenish the buffering capacity of the PBS. All specimens were incubated at 37ºC. After the completion of experiments, the specimens were sent to the push-out test. Analysis of data was analyzed using descriptive and inferential statistics both. The software SPSS 17.0, EPI_INFO 6.0 version and Graph Pad Prism 5.0 version was used and p&lt;0.05 is considered as level of significance. Result and conclusion : Highest push out bond strength was seen with ERRM at all incubation times followed by mineral trioxide aggregate and Biodentine .It has been observed that increase in the incubation time had increased push-out bond strength of the material significantly.

A comparative evaluation of remaining dentin thickness following biomechanical preparation of teeth using different rotary file systems: An in vitro study.

Aim:The aim of the study is to compare and evaluate the remaining dentin thickness following biomechanical preparation of teeth using different rotary file systems.Materials and Methodology:Sixty noncarious mandibular premolar teeth were collected and decoronated at the level of cementoenamel junction with a diamond disc. All specimens were randomly divided into 5 experimental groups – ProTaper Next (Dentsply Mallifer), Mtwo (VDW, Antaeus, Munich, Germany), RaCe (FKG, La Chaux-de-Fonds, Switzerland), Hyflex electro-discharge machining (EDM) (Coltene-Whaledent, Allstetten, Switzerland), NeoNiTi (Neolix, France) and 1 control group of 10 teeth each. After mounting the samples on a modeling wax sheet, preoperative cone-beam computed tomography (CBCT) scans were taken. Biomechanical preparation of canals was done following the assigned protocol of manufacturers. Postoperative CBCT scans were taken and comparison was carried out with preoperative scans.Statistical Analysis Used:Difference among the groups was analyzed by post hoc Turkey and analysis of variance tests. A P < 0.05 was considered statistically significant for all tests.Results:A comparison of preinstrumentation and postinstrumentation CBCT images revealed ProTaper Next group to remove more dentin at 7 mm as opposed to other groups in mesiodistal direction. However, no statistical difference was evident between ProTaper Next, MTwo, Race, Hyflex EDM, NeoNiTi file systems at 3 mm, 5 mm, and 7 mm in buccolingual direction. A statistically nonsignificant difference was evident between MTwo, Race, Hyflex EDM, NeoNiTi file systems at 3 mm, 5 mm, and 7 mm in both mesiodistal and buccolingual direction.Conclusion:Race file system performed better and removed lesser dentin in both buccolingual and mesiodistal directions. More dentin was removed at the coronal in mesiodistal direction with the use of ProTaper Next, and significant difference was seen between Protaper Next group and other groups in the study.

Comparison of the efficacy of Icon resin infiltration and Clinpro XT varnish on remineralization of white spot lesions: An in-vitro study.

OBJECTIVE:To compare the efficacy of Icon resin infiltration and Clinpro XT varnish on remineralization of white spot lesions using a polarized light microscope (PLM).MATERIALS & METHODS:Artificial white spot lesions were created on a sample of 40 extracted human premolar teeth by immersing in a demineralizing solution. All samples were randomly allocated to two groups of 20 each; Group A: Icon resin infiltration and Group B: Clinpro XT varnish. Teeth were sectioned along the buccolingual plane using a diamond disc. Specimens were observed under the PLM (4× magnification) at three deepest measurements and their averages were calculated to obtain the mean penetration depth. The data obtained were analyzed using SPSS software (version 22.0). Independent samples t-test and group statistics were used to compare the two groups. In all statistical tests, the significance level was set at 5% (P < 0.05).RESULTS:Both Icon resin infiltration and Clinpro XT groups showed a statistically significant difference (P = 0.00) in the penetration depth. Icon resin infiltration group showed a significantly higher penetration depth (24.46 μm) compared to the Clinpro XT group (12.34 μm). Group A showed a greater mean penetration depth (17.07 ± 4.35 μm) when compared to group B (7.68 ± 1.81 μm).CONCLUSION:Icon resin infiltration showed a significantly higher penetration depth and is more effective on remineralization of white spot lesions when compared to Clinpro XT varnish.

Optical coherence tomography evaluation of deep dentin crack removal techniques

BackgroundThis in vitro study used optical coherence tomography for noninvasive evaluation of the effectiveness of current clinical techniques to remove deep coronal dentin cracks. MethodsStandard dentin cracks were induced on the pulpal floor of 40 decoronated, extracted, sound human posterior teeth using a diamond disk, resembling cracks extending from marginal ridges. The specimens were randomly assigned to 1 of 5 treatment groups for crack removal using airborne-particle abrasion or a bur (fissure, small round, medium round, or tapered fine diamond). Optical coherence tomographic scans were obtained before and after the crack removal. Three-dimensional image registration analyzed the amount of dentin removed and the dimensions of cracks initiated or propagated in each treatment group. ResultsParticle abrasion resulted in the smallest crack propagation in each dimension, which was significantly different from all bur groups (Mann-Whitney, P < .01). Removed dentin depth and width differed among burs (P < .05). All burs resulted in a degree of crack formation, and there was no difference in crack dimensions among bur groups (P > .05). The amount of removed dentin during crack treatment was the largest in the particle abrasion group, which was significantly different from those of the bur groups (Mann-Whitney, P < .005). ConclusionsDental burs used with the purpose of removing pulpal floor dentin cracks induced new small cracks and extended existing cracks, and the volume of removed dentin depended on the shape and size of the bur. Air particle abrasion induced the fewest new cracks despite removing larger dentin volume.

Evaluation of Marginal and Internal Fit at Implant-Abutment Interface of Original and Compatible Nonoriginal Abutments.

Is to measure the peripheral and internal gap at the implant-abutment interface of an implant system connected to its original or compatible non-original abutments. Twenty implants were assembled with four different types of abutments having the same conical internal interface. All abutments were considered compatible with Tx Astra Tech Implant SystemTM. Four groups were created and each group of five implants was connected to a different abutment; Ti DesignTM abutments (group A), DualTM abutments (group B), Natea plusTM abutments (group C) and ImplanetTM abutments (group D). The peripheral gaps between implant and abutment were observed in three points facing the flat surface of the abutment. The implant-abutment assemblies were then embedded in resin and grinded in the mesio-distal direction of the scalloped abutment margin using a diamond disk at very low speed and under water-cooling. The inner aspect of the implant abutment interface was observed in three different points, on the coronal border of the connection, in the middle area and on the apical border of the implant-abutment interface. The mean gap width was 0.543 ± 0.09 μm for group A and, respectively, 0.708 ± 0.1232 μm, 0.726 ± 0.0891 μm and 0.818 ± 0.0851 μm for groups B, C and D. When comparing group, A to B and C, a highly significant difference in numbers was obvious while an even higher variation was observed with group D. External and internal fit of components is better when using original components.