Internal root resorption in permanent mandibular molars - A rare entity: Report of two cases

The cases presented here aim to highlight the occurrence of a very rare internal root resorption (IRR) of inflammatory type among mandibular molars (prevalence 0.01%-1%). Patients reported in the outpatient department with a chief complaint of pain in the lower posterior region of the jaws, on thorough clinical and radiological examinations a diagnosis of irreversible pulpitis was made and nonsurgical root canal treatment was planned using thermoplastic obturation technique along with the use of magnification, cone-beam computed tomography, endosonics, and intracanal medicament to attain a successful outcome. Six-month follow-up showed arrest of IRR. This report of two cases with a literature review discusses the etiology, prevalence of IRR, the clinical decision, and the therapeutic management. Early detection of such resorption is the key to successful management and preserves the integrity of the tooth.

Does the presence of full-coverage crown interfere with removal of obturation material: A cone-beam computed tomography image segmentation volumetric analysis

Aim

The aim of this study was to assess and compare the influence of the presence of full-coverage crown on the obturation material removal efficiency of different retreatment file systems.

Materials and Methods

Sixty extracted, human, maxillary premolars were accessed, instrumented, and obturated with gutta-percha and AH Plus sealer. The samples were scanned with cone-beam computed tomography and volume of obturating material was measured using ITK-SNAP volumetric software. Samples were divided (n = 30) into with and without all metal full-coverage crown groups. Each group was then subdivided into three subgroups (n = 10) based on retreatment file used (ProTaper URS, HyFlex Remover, and NeoEndo). The volume of remnants of obturating material was remeasured by image segmentation using ITK-SNAP volumetric software. One-way analysis of variance, followed by the Tukey's post hoc test, was used for data analysis, with a significance level of 5%.

Results

A significant difference in percentage remnant of obturating material after retreatment file was observed on overall comparison between with (29.84%) and without crown (21.79%) groups (P < 0.05). Each file system removed significantly more obturating material in without crown samples than with crown samples (P < 0.05). The percentage remnant of obturating material after retreatment file use was as follows: ProTaper URS > NeoEndo retreatment file > HyFlex Remover. All file systems showed significantly different (P < 0.05) efficiency in removal of obturating material.

Conclusions

None of the retreatment file systems were able to remove obturating material completely. The presence of full-coverage crown negatively impacted the efficiency of retreatment files for the removal of obturating material. HyFlex Remover performed better than NeoEndo which was better than ProTaper URS.

Effect of monowave and polywave light curing on the degree of conversion and microhardness of composites with different photoinitiators: An in vitro study

Aim

The purpose of this study was to evaluate the effect of light-curing units (LCUs) on the degree of conversion (DC) and microhardness of composites with varying photoinitiator systems.

Materials and Methodology

Two groups were formed based on LCU - monowave (Group M) and polywave (Group P). Each group was further divided into two subgroups based on photoinitiator systems - combination of camphorquinone (CQ), Ivocerin, and 2,4,6-trimethylbenzoyl diphenylphosphine oxide (Subgroup CIT) and only CQ (Subgroup C) in the composite. Samples prepared were 4 mm thick. Microhardness was measured at bottom surface by Vickers hardness tester, and DC was evaluated by Fourier transformation infrared spectroscopy.

Statistical Analysis

Kolmogorov-Smirnov test was used.

Results

Both the mean microhardness and DC of composite in subgroup C were similar (P > 0.05) in Group M (52.42 ± 2.67 and 48.30 ± 5.81) and Group P (51.77 ± 1.96 and 48.50 ± 4.87). The mean microhardness of composite containing a combination of photoinitiators was more in Group P (57.09 ± 2.61) as compared to Group M (47.37 ± 3.51). The mean DC was higher in Group P (59.75 ± 5.30) as compared to Group M (39.70 ± 3.57), and these differences were statistically significant (P < 0.05).

Conclusion

The type of LCU affects DC and microhardness only in the case of composites containing a combination of photoinitiators.

Effectiveness of polyhexamethylene biguanide, chlorhexidine, and calcium hydroxide intracanal medicament against intraradicular mature polymicrobial biofilm: A microbiological study

Aim

To compare the effectiveness of different intracanal medicaments against polymicrobial biofilm formed by Enterococcus faecalis, Staphylococcus aureus, and Candida albicans.

Materials and Methods

Eighty mature human roots with intraradicular polymicrobial biofilm were randomly assigned into four groups (n = 20). Intracanal medicaments 0.2% polyhexamethylene biguanide (PHMB), 2% chlorhexidine (CHX), and calcium hydroxide (CH) were applied into the root canals. Collected dentine samples were tested at 7^th, 15^th, and 30^th day for microbial growth, and the colony-forming units per ml (CFU/ml) were determined.

Results

The CFU/ml data were analyzed using unpaired t-test and one-way ANOVA-F comparison test. All medicaments resulted in a significant reduction (P < 0.05) in microbial growth at all time intervals compared to the control group. CHX and PHMB showed a similar reduction in CFU/ml at 7^th and 15^th day but significantly more than CH at all time intervals. At 30^th day, PHMB caused a significantly more reduction in CFU/ml than CHX.

Conclusions

All the three tested intracanal medicaments such as CH, CHX, and PHMB Gel were effective in reducing the microbial count. CH has a limited antimicrobial effect against the polymicrobial biofilm found inside the root canal. 2% CHX gel has a time-dependent antimicrobial effect. PHMB has a superior antimicrobial effect in comparison with CHX and CH.

Do whey protein beverages affect the microhardness of composites? A laboratory study

Background:

Whey protein supplements might be a potential risk factor for the restoration surface due to its pH and lactose content.

Aim:

The study aimed to evaluate the effect of whey protein beverages on the microhardness of four restorative composites with different microstructures (Filtek Z 350XT, Filtek Z 250XT, Filtek Bulk Fill (FBF), and Filtek P 60).

Materials and Methodology:

Forty disc-shaped samples from each material (in total 160) were prepared and wet polished. The samples of each group were randomly divided into four subgroups and subjected to four immersion media namely, whey protein Concentrate (WPC), whey protein Isolate (WPI), whey protein water (WPW), and distilled water (DW). The immersion protocol was performed twice for 10 min daily for 30 days followed by immersion in artificial saliva for another 10 min and stored in DW till the next cycle. The pre immersion and post immersion microhardness of all the samples were recorded with a Microhardness Tester FM-800. Data obtained were statistically analyzed using SPSS 25 software.

Results and Conclusions:

All composites exhibited decline in microhardness, except for FBF. P 60 composites which showed the highest decline in microhardness. WPC and WPI caused the greatest reduction in microhardness compared to WPW.

Effect of intracanal and extracanal heating on pulp dissolution property of continuous chelation irrigant

Context

Extracanal and intracanal heating of sodium hypochlorite (NaOCl) improve its pulp dissolution, but limited literature is available on its effect as a combined single irrigant with etidronate.

Aim

The aim of this study is to compare the effect of temperature on the effectiveness of NaOCl and continuous chelation protocol on the time required for the dissolution of vital and necrotic pulp.

Materials and Methods

Dissolution time of 120 standardized bovine (buffalo) pulp fragments, divided into 12 subgroups based on tissue type (vital/necrotic), irrigant (NaOCl/continuous chelation), and temperature (extracanal, intracanal, and nonheated irrigant), was noted. Conical glass tips mimicking the root canal were considered specimen containers. About 0.2 ml of irrigant corresponding to the irrigation protocol was taken in them and then pulp samples were added to it. Samples were observed using loupes under 2.5 X magnification. Dissolution time was recorded using a stopwatch. The study was approved by the Institutional Ethical Committee (SDC/2019/591).

Statistical Analysis Used

Two-way analysis of variance; statistical product and service solutions version 25. The level of significance was set at P < 0.05.

Results

Time for pulp dissolution by continuous chelation mixture was significantly more as compared to NaOCl alone in all subgroups. Pulp tissue dissolution for both vital and necrotic pulp was improved by the increase in temperature of both irrigants and dissolution time was more for necrotic than vital tissue. Pulp tissue dissolution was significantly better by intracanal heating as compared to extracanal heating.

Conclusion

Although intracanal heating of continuous chelation mixture improves its pulp dissolution capacity significantly as compared to extracanal heating and nonheating protocol but pulpal dissolution capacity of nonheated 5% NaOCl still remains significantly better as compared to intracanal and extracanal heated continuous chelation mixture.

To compare the continuous and intermittent irrigation method on the removal of dentin debris from root canals and to evaluate the dynamics of irrigant flow using computational fluid dynamics

Aim:

This study aimed to compare the efficiency of continuous and intermittent irrigating methods on the removal of dentin debris from the simulated grooves and to evaluate the dynamics of irrigant using computational fluid dynamics (CFD).

Methodology:

Seventy-five extracted human permanent maxillary canines were selected. Access cavities were made, working length was determined, and canals were prepared by crown down technique. The teeth were split longitudinally and standard groove 2.0 mm in length was made in split halves and each groove was filled with dentin debris and the images were taken under a microscope (E200). The halves were re-assembled and divided into five groups based on different irrigation methods. Group 1: ultrasonic Irrigation with continuous flow for 3.0 min; Group 2: ultrasonic irrigation with continuous flow for 1.5 min; Group 3: ultrasonic irrigation with intermittent flow for 3.0 min; Group 4: ultrasonic irrigation with the intermittent flow for 1.5 min; and Group 5: syringe irrigation for 1 min. The root halves were again separated and re-evaluated for debris elimination after the irrigation protocol for all the groups separately. The effect of time and method of passive ultrasonic irrigation were compared. For the computational fluid analysis, a GAMBIT 2.2 (Ansys) software was used for mesh construction. FLUENT 6.2 (Ansys) software was used to set the boundary conditions and reconstruction of the canal; flow patterns and turbulence were graphically constructed.

Results:

The continuous irrigation methods were better at debris removal than intermittent irrigation flow methods. The CFD showed that the turbulence of flow of irrigant was dependent on the inlet velocity and pressure of the irrigant.

Conclusion:

Debris removal from the simulated grooves was better with continuous irrigation compared with intermittent irrigation. CFD study revealed that the turbulence that was affected by the velocity and pressure of the irrigant introduced and is a variable entity.

Effect of prophylactic instrumentation on surface roughness of tooth-colored restorative material: An in vitro study

Aim:

To compare and evaluate the surface characteristics of different restorative materials used for restoration of cervical defects when subjected to periodontal prophylactic instrumentation techniques.

Materials and Methodology:

Sixty box-shaped cavities were prepared on the labial surface of decoronated permanent maxillary anterior teeth which were randomly divided into two groups (n = 30) based on the instrumentation technique Group I: Manual instrumentation using curettes and Group II: Ultrasonic instrumentation. The samples were further divided into three subgroups based on restorative material subgroups I V and II V-restored with Vitremer, subgroups I F and II F-restored with Filtek Z 250 XT and subgroups I D and II D-restored with Dyract flow, respectively. After finishing and polishing, the samples were subjected to surface profilometry analysis for determining the surface roughness values (Ra). Thereafter, the restored surfaces of all the samples in different subgroups were subjected to prophylactic instrumentation with Gracey's curettes (Group I) and ultrasonic scalers (Group II). Ra values were recorded again after prophylactic instrumentation and after polishing. The data thus obtained were subjected to the statistical analysis using the independent t-test and one-way ANOVA (p<0.05).

Results:

Ra values were significantly higher for both manual and ultrasonic prophylaxis compared to preprophylaxis and postpolishing in all the three restorative materials. Ultrasonic scaling produced significantly higher Ra for subgroup V as compared to subgroup F and subgroup D, whereas the difference between the materials was not significant for manual scaling.

Conclusion:

Manual prophylaxis resulted in significant reduction in surface roughness of all the three restorative materials while ultrasonic prophylaxis resulted in significant reduction for Vitremer only. Polishing after scaling significantly reduced the effect of both manual and ultrasonic prophylaxis on surface roughness.

Comparative evaluation of substantivity of two biguanides - 0.2% polyhexanide and 2% chlorhexidine on human dentin

Background:

Substantivity is one of the desirable characteristics of root canal irrigants. Among conventional endodontic irrigants, only chlorhexidine (CHX) is known to exert significant substantivity on root canal dentin. This study explored the substantivity activity of a polymeric biguanide-poly hexamethylene biguanide (PHMB).

Aim:

The aim of this study was to determine the substantivity of a polymeric biguanide - 0.2% PHMB and compare it with that of 2% CHX.

Materials and Methods:

To evaluate and compare the substantivity of 0.2% PHMB and 2% CHX on root canal dentin, dentin disks were prepared and substantivity after 1 h, 24 h, 7 days and 21 days was measured using spectrophotometry.

Statistical Analysis Used:

The data so obtained were analyzed, and the intergroup comparison was made using unpaired t-test.

Results:

The results of this study indicated that 0.2%. PHMB exerts significantly greater substantivity than 2% CHX on human dentin.

Conclusion:

Within the limitations, this study supports the use of 0.2% polyhexanide as an endodontic irrigant based on its property of substantivity.

Effect of mechanical alteration of enamel surface on shear bond strength of different bonding techniques

Aim

This study was conducted to evaluate the effect of mechanical alteration of enamel surface on shear bond strength in different bonding techniques.

Materials and Methods

Seventy samples were fabricated and randomly divided into three groups: Group A (n = 30) - prepared enamel surfaces, Group B (n = 30) - unprepared enamel surfaces, and Group C (n = 10) - prepared enamel surfaces + etch and rinse which served as a control group. Group A and Group B were further divided into three subgroups (n = 10), sub-Group A1, B1 (nanohybrid composite + self-etch), sub-Group A2, B2 (self-adhering composite), and A3, B3 (self-adhering composite + self-etch). Teflon ring molds were used to make composite resin cylinders with the specific bonding protocol of each group. Shear bond strength testing was conducted, and data were analyzed.

Results

Mean shear bond strength values were as follows: C> A1> A3>A2>B1> B3> B2.

Conclusions

Prepared enamel surfaces resulted in higher shear bond strength values as compared to unprepared enamel surfaces. Prior application of self-etch agent resulted in higher shear bond strength values of self-adhering composite in prepared and unprepared enamel surfaces.

Effect of ultrasonic root-end cavity preparation on dentinal microcrack formation: A micro-computed tomography study

Background:

Root-end preparation during surgical endodontics may produce dentinal microcrack formation and/or propagation, leading to vertical root fractures.

Aim:

This study aimed to evaluate and compare the microcrack formation and propagation during ultrasonic root-end cavity preparation, with diamond- and zirconium nitride-coated tips using micro-computed tomography (CT).

Methodology:

Twenty-eight extracted, mature, free-of-defect, mandibular premolars were decoronated and micro-CT scanned for the presence of preexisting microcracks. Samples were prepared till F4, were obturated, and were re-scanned to determine an increase in the number of microcracks. After 3 mm of root-end resection, the samples were randomly divided for ultrasonic root-end preparation into Group 1 (n = 12): preparation was done with ProUltra Surg tip, Group 2 (n = 12): preparation was done with KiS tip, and Group 3 (n = 4): no preparation was done. The samples were rescanned, and data collected were analyzed using ANOVA and Student's t-test. The level of significance was set at 5%.

Results:

Preexisting microcracks were observed in few samples. The mean percentage number increase of microcracks after root-end preparation in ProUltra Surg group was 1.25 and in KiS group, it was 0.5. The difference in mean percentage increase for the number of microcracks after root-end cavity preparation using ProUltra Surg tip and KiS tip was 0.75. However, this difference was not statistically significant (P = 0.34).

Conclusion:

Both diamond- and zirconium nitride-coated ultrasonic tips resulted in more number of dentinal crack formation and propagation when preexisting cracks were present.

Comparison of fluoride ion release and alkalizing potential of a new bulk-fill alkasite

AIM

This study was conducted to evaluate and compare fluoride ion release by Cention-N (self-cure and light-cure) and conventional glass-ionomer cement (GIC) at different pH and time intervals.

METHODOLOGY

Cavities of similar dimensions were prepared in mandibular molars and restored with Cention-N (by self-cure and light-cure techniques) and GIC. Samples were stored in deionized water, and the cumulative fluoride ion release and change in pH were assessed utilizing spectrophotometer and pH meter, respectively, at the end of 7 days, 14 days, and 21 days. The data thus obtained were statistically analyzed.

RESULTS

All the tested materials released fluoride ions in both acidic and neutral pH at all time intervals, and the fluoride ion release was significantly higher (<0.05) in acidic pH as compared to neutral pH except in GIC. All the groups showed a statistically significant increase in pH in acidic medium, whereas no significant increase was observed in neutral medium.

CONCLUSIONS

Cention-N (self-cure) has the highest fluoride ion release and alkalizing potential in acidic pH as compared to Cention-N (light-cure) and GIC.

Effect of Different Finishing and Polishing Systems on the Surface Roughness of Resin Composite and Enamel: An In vitro Profilometric and Scanning Electron Microscopy Study

Aim

The aim is to compare and evaluate the different finishing and polishing systems for the change in surface roughness of resin composites and enamel.

Materials and Methods

To conduct the study, 30 extracted human maxillary central incisors were selected, decoronated, and molded in self-cure acrylic molds. A box-shaped cavity of dimensions 3 mm × 3 mm × 2 mm was prepared in all the teeth. A nanohybrid composite resin (Filtek Z250) was then used to restore the prepared cavities. Thirty samples were divided into two groups, control group (Group A, n = 10) and experimental group (Group B, n = 20). The samples in Group A were cured through the Mylar matrix. The experimental group, i.e., Group B was divided into two subgroups, i.e., Subgroup BX, n = 10 in which Sof-Lex polishing system was used for polishing the tooth surface and Subgroup BF, n = 10 in which Shofu composite polishing system was used. The mean surface roughness (Ra in μm) of the composite restoration as well as for the enamel surface of all the samples before and after polishing was measured with a contact profilometer, and the values were correlated with scanning electron microscopy.

Results

The statistical analysis was carried out using paired t-test. The results exhibited a significant decrease in the surface roughness of the resin composite and enamel surface irrespective of the finishing and polishing system used. The mean surface roughness values demonstrated by Mylar matrix was the lowest followed by Sof-Lex polishing system. Shofu polishing system demonstrated the highest surface roughness values.

Conclusion

Finishing and polishing of composite restoration can achieve a surface roughness similar to that of enamel. Involvement of marginal enamel in finishing and polishing procedures carried out for composite restoration results in smoother enamel surface.

In vitro evaluation of the contact angle formed between AH Plus, Hybrid Root Seal and mineral trioxide aggregate Plus sealer with dentin and gutta-percha

Aim:

The purpose of this study was evaluation and comparison of the contact angle of new root canal sealers – Hybrid Root Seal, mineral trioxide aggregate (MTA) Plus, and the conventional AH Plus sealer with dentin and gutta-percha.

Materials and Methods:

Two groups (Group D – dentin and Group G – gutta-percha) of 18 samples each were further randomly divided into 3 subgroups based on the type of sealer used, that is, AH Plus, Hybrid Root Seal, and MTA Plus. Contact angle measurement device (Phoenix 300) was used to measure the contact angle of the sealers on both dentin and gutta-percha. The results thus obtained were analyzed using one-way analysis of variance and Student's t-test.

Results:

MTA Plus recorded significantly higher values of contact angle on both the substrates, that is, dentin and gutta-percha when compared to AH Plus and Hybrid root canal sealer. The lowest value of contact angle in gutta-percha and dentin was shown by Hybrid root canal sealer and AH Plus, respectively.

Conclusion:

Both AH Plus and Hybrid Root Seal exhibited lower contact angle values, and hence, better wettability on both dentin and gutta-percha as compared to MTA Plus.

Induction of dentinal microcracks during postspace preparation: A comparative microcomputed tomography study

Introduction

This study evaluated and compared techniques of postspace preparation for induction of dentinal microcracks utilizing microcomputed tomography (CT).

Materials and Methods

A total of 45 extracted micro-CT scanned mandibular premolars were prepared and obturated. After the second micro-CT, samples were divided into three groups (n = 15). In Group 1, postspace preparation was done using hand K files up to the size of #110. In Group 2, postspace preparation was done using Peeso reamer up to the number of #3. In Group 3, postspace preparation was done using ParaPost XT Drills with the tip diameter of 1.1 mm. Thereafter, the third micro-CT scan was performed for microcracks evaluation, and statistical analysis was performed.

Results

Few unprepared samples showed the presence of microcracks (1.54%). There was statistically significant (P < 0.05) percentage increase in the number of microcracks after root canal preparation and obturation (5.44%) and after postspace preparation (8.35%). The percentage increase in microcracks observed for Group 1, 2, and 3 from obturation to postspace preparation was 0.19%, 4.21%, and 6.86%. There was a significant difference among the three techniques of postspace preparation (P < 0.05).

Conclusion

Microcracks may exist preoperatively. Postspace preparation increased the number of microcracks irrespective of the technique utilized. ParaPost XT Drills produces maximum microcracks in the root dentin followed by Peeso reamers and K files.

Effect of root canal preparation, obturation, and retreatment on the induction of dentinal microcracks: A microcomputed tomography study

Introduction:

This study evaluated the effect of root canal preparation, obturation, and different techniques of retreatment on the percentage increase in the number of dentinal microcracks using microcomputed tomography (CT) analysis.

Materials and Methods:

Forty-five mandibular premolars after micro-CT scanning were prepared using Protaper universal files up to F4 and obturated. After the second micro-CT scanning again, the samples were randomly divided into three groups (n = 15) for retreatment procedure. In Group 1, retreatment was done with Protaper universal D1, D2, and D3 retreatment files followed by Protaper universal file till F4. In Group 2, retreatment was performed with R-Endo reciprocating motion, Re, R1, R2, R3, and Rs followed by Hero Shaper size #40. In Group 3, retreatment was performed with H-files and xylene till size #40. After gutta percha removal, the samples were again scanned for micro-CT for the evaluation of percentage increase in dentinal microcracks. Data were analyzed using “Kruskal–Wallis test ANOVA” and “student t-test” at 5% level of significance.

Results:

Few unprepared samples showed preexisting microcracks. There were statistically significant percentage increase dentinal cracks after root canal preparation and obturation as well as after retreatment procedure with statistically significant percentage increase in the number of dentinal microcracks between all three groups.

Conclusion:

Intraradicular procedures such as shaping and cleaning and obturation as well as the use of retreatment file lead to the induction and propagation of dentinal microcracks. In the present study, the maximum microcracks were produced with Protaper universal retreatment file system followed by R-Endo system. H-files produced minimum cracks during retreatment procedures.

Evaluation of marginal sealing ability of self-adhesive flowable composite resin in Class II composite restoration: An in vitro study

Aim:

The aim of this study is to evaluate the marginal sealing ability of self-adhesive flowable composite resin when used as a liner in Class II composite restoration with and without aging.

Materials and Methods:

A total of 120 standardized Class II tooth preparations with gingival margins 1 mm coronal and apical to cementenamel junction (CEJ) were prepared on 60 extracted permanent mandibular molars and were randomly divided into eight equal Groups: Group 1: cavities coronal to CEJ and restored with Dyad flow liner + Herculite ultra, Group 2: same as Group 1 but cavities margins apical to CEJ, Group 5: cavities coronal to CEJ and restored with only Herculite ultra, and Group 6: same as Group 5 but cavities apical to CEJ. Groups 3,4,7,8 were similar to Groups 1,2,5,6, respectively, but were aged for 6 months. After thermocycling, microleakage testing was done using 0.5% basic fuchsin dye.

Result:

At cervical level, Group 5 exhibited statistically lower (P = 0.006) microleakage than Group 6, and Group 1 showed lesser microleakage than Group 5 (P = 0.162). Group 2 exhibited significantly less microleakage than Group 6 (P = 0.002). Increased microleakage was observed in aging Groups; however, the difference with nonaging Groups was not statistically significant (P > 0.005).

Conclusion:

Margins of the cavity in cementum can be better sealed by placing self-adhesive liner and is not affected by aging.

Four cuspal maxillary second premolar with single root and three root canals: Case report

Traditional configuration of maxillary second premolars has been described to have two cusps, one root and one or two root canals. The endodontic literature reports considerable anatomic aberrations in the root canal morphology of maxillary second premolar but the literature available on the variation in cuspal anatomy and its relationship to the root canal anatomy is sparse. The purpose of this clinical report was to describe the root and root canal configuration of a maxillary second premolar with four cusps.

Effect of methods of evaluation on sealing ability of mineral trioxide aggregate apical plug

Aim:

The purpose of the study was to evaluate and compare the sealing ability of mineral trioxide aggregate (MTA) with three different methods.

Materials and Methods:

Forty single canal teeth were decoronated, and root canals were enlarged to simulate immature apex. The samples were randomly divided into Group M_D = MTA-angelus mixed with distilled water and Group M_C = MTA-angelus mixed with 2% chlorhexidine, and apical seal was recorded with glucose penetration method, fluid filtration method, and dye penetration methods and compared.

Results:

The three methods of evaluation resulted differently. The glucose penetration method showed that M_D sealed better than M_C, but difference was statistically insignificant (P > 0.05). The fluid filtration method resulted that Group M_C was statistically insignificant superior to Group M_D (P > 0.05). The dye penetration method showed that Group M_C sealed statistically better than Group M_D.

Conclusion:

No correlation was found among the results obtained with the three methods of evaluation. Addition of chlorhexidine enhanced the sealing ability of MTA according to the fluid filtration test and dye leakage while according to the glucose penetration test, chlorhexidine did not enhance the sealing ability of MTA. This study showed that relying on the results of apical sealing by only method can be misleading.

Effect of phytic acid, ethylenediaminetetraacetic acid, and chitosan solutions on microhardness of the human radicular dentin

AIM

The purpose of this study was to evaluate the effect of phytic acid, ethylenediaminetetraacetic acid (EDTA), and chitosan solutions on the microhardness of human radicular dentin.

MATERIALS AND METHODS

Thirty dentin specimens were randomly divided into three groups of 10 specimens each according to the irrigant used: G1 - 1% phytic acid, G2 - 17% EDTA, and G3 - 0.2% chitosan. A standardized volume of each chelating solution was used for 3 min. Dentin microhardness was measured before and after application at the cervical, middle, and apical levels with a Vickers indenter under a 200-g load and a 10-s dwell time. The results were analyzed using one-way analysis of variance (ANOVA) and Student's t test.

RESULTS

Microhardness of the radicular dentin varied at the cervical, middle, and apical levels. EDTA had the greatest overall effect, causing a sharp percentage reduction in dentin microhardness with a significant difference from phytic acid and chitosan (P = 0.002). However, phytic acid and chitosan differed insignificantly from each other (P = 0.887).

CONCLUSION

All tested chelating solutions reduced microhardness of the radicular dentin layer at all the levels. However, reduction was least at the apical level. EDTA caused more reduction in dentin microhardness than chitosan while phytic acid reduced the least.

An in vitro comparative evaluation of different intraorifice barriers on the fracture resistance of endodontically treated roots obturated with gutta-percha

AIM

To compare and evaluate the root reinforcement potential of four different intraorifice barriers: Mineral trioxide aggregate (MTA), resin-modified glass ionomer cement (RMGIC), fiber-reinforced composite (FRC), and nanohybrid composite (NC).

MATERIALS AND METHODS

Seventy-five mandibular premolars were decoronated to a standardized length, and prepared and obturated with gutta-percha and AH Plus sealer. Except for control specimens, the coronal 3-mm gutta-percha was removed and filled with different materials. The specimens (75) were divided into five groups (n = 15) on the basis of the intraorifice barrier material used. Group 1: MTA, Group 2: RMGIC, Group 3: FRC, Group 4: NC, Group 5: no barrier (control). Fracture resistance of the specimens was tested.

RESULTS

Fracture resistance of roots was significantly affected by the type of intraorifice barrier used and the following pattern was observed: RMGIC > FRC > NC > MTA.

CONCLUSION

Intraorifice barriers can be regarded as a viable choice to reduce the occurrence of postendodontic root fractures. Among the four tested materials, RMGIC showed the maximum reinforcement.

Evaluation of effect of addition of 2% chlorhexidine on the sealing ability of Biodentine: An in vitro study

Aim:

To evaluate the effect of the addition of 2% chlorhexidine on the sealing ability of Biodentine.

Materials and Methods:

Forty-six extracted human premolar teeth with single canal and apical foramen were selected, cleaned, and decoronated to standardize the length of 17 mm. Canals were prepared using ProTaper rotary files till size F4. The samples were divided into 2 experimental groups of 20 samples each on the basis of absence/presence of 2% chlorhexidine in liquid: Group B_M = Biodentine mixed with the provided liquid, Group B_C = Biodentine mixed with 2% chlorhexidine in provided liquid. Three samples, each were assigned to control groups: Group B_P (positive control) = No root end filling was placed, Group B_N (negative control) = Root ends were filled as in Group B_M, and entire external surface was coated with sticky wax. The samples were then evaluated for the apical sealing using fluid filtration method.

Results:

Results were analyzed using Student's t-test (P ≤ 0.05). Group B_C showed the better sealing ability (3.06) as compared to Group B_M (3.85). However, the difference was statistically insignificant (P > 0.05).

Conclusion:

Addition of 2% chlorhexidine to the liquid enhanced the sealing ability of Biodentine.

Effect of technique of sealer agitation on percentage and depth of MTA Fillapex sealer penetration: A comparative in-vitro study

Aim:

To compare the effect of three root canal sealer activation techniques on percentage and depth of sealer penetration of MTA Fillapex and AH Plus sealers.

Materials and Methods:

Sixty teeth prepared till F5 ProTaper size were divided into three equal groups on the basis of sealer activation technique (G1: Ultrasonics, G2: Lentulo spiral, and G3: Counter-clockwise rotary motion). Each group was further divided into two equal subgroups on the basis of type of sealer used: AH Plus (Denstply, Konstanz, Germany) or MTA Fillapex (Angelus, Londrina, PR, Brazil) and obturated with gutta-percha. Horizontal sections at 3 and 6 mm from the apex were obtained and the percentage and depth of penetration of sealers into dentinal tubules were measured using confocal laser scanning microscopy (CLSM). Statistical analysis was performed utilizing Kruskal-Wallis and Mann-Whitney U tests with a significance level of 5%.

Results:

G1 showed significantly (P < 0.001) high percentage and depth of sealer penetration than G2 and G3 while the difference was insignificant (P > 0.05) between G2 and G3.

Conclusion:

Percentage and depth of sealer penetration are influenced by the type of sealer used sealer activation technique and by the root canal level. Ultrasonic method of sealer activation and MTA Fillapex showed the best results.

Multiple idiopathic external apical root resorption: A rare case report

Multiple idiopathic external apical root resorption (MIEARR) is a relatively rare condition affecting multiple teeth in a dentition. As the condition is nonsymptomatic, a case is usually detected as an incidental radiographic finding. However, it may cause pain and mobility in severe cases. It is sometimes self-limiting or sometimes may progress to tooth loss. This paper presents a case of external apical root resorption involving multiple teeth in which etiology was not identified, so idiopathic root resorption was considered as a diagnosis of exclusion.

Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials

Background:

Evaluation of microleakage is important for assessing the success of new restorative materials and methods.

Aim and Objectives:

Comparative evaluation of microleakage in Class II restorations using open vs. closed centripetal build-up techniques with different lining materials.

Materials and Methods:

Standardized mesi-occlusal (MO) and distoocclusal (DO) Class II tooth preparations were preparedon 53 molars and samples were randomly divided into six experimental groups and one control group for restorations. Group 1: Open-Sandwich technique (OST) with flowable composite at the gingival seat. Group 2: OST with resin-modified glass ionomer cement (RMGIC) at the gingival seat. Group 3: Closed-Sandwich technique (CST) with flowable composite at the pulpal floor and axial wall. Group 4: CST with RMGIC at the pulpal floor and axial wall. Group 5: OST with flowable composite at the pulpal floor, axial wall, and gingival seat. Group 6: OST with RMGIC at the pulpal floor, axial wall, and gingival seat. Group 7: Control — no lining material, centripetal technique only. After restorations and thermocycling, apices were sealed and samples were immersed in 0.5% basic fuchsin dye. Sectioning was followed by stereomicroscopic evaluation.

Results:

Results were analyzed using Post Hoc Bonferroni test (statistics is not a form of tabulation). Cervical scores of control were more than the exprimental groups (P < 0.05). Less microleakage was observed in CST than OST in all experimental groups (P < 0.05). However, insignificant differences were observed among occlusal scores of different groups (P > 0.05).

Conclusion:

Class II composite restorations with centripetal build-up alone or when placed with CST reduces the cervical microleakage when compared to OST.

Effect of addition of 2% chlorhexidine or 10% doxycycline on antimicrobial activity of biodentine

Aim:

The purpose of this in vitro study was to determine whether the addition of 2% chlorhexidine gluconate or 10% doxycycline would enhance the antimicrobial activity of Biodentine against Staphylococcus aureus (ATCC-25923), Enterococcus faecalis (ATCC-29212), Candida albicans (ATCC-90028), and Streptococcus mutans (MTCC-497).

Materials and Methods:

Three wells of 4 mm diameter and 4 mm depth on each plate were prepared on the agar medium with standardized suspensions of each microorganism. Biodentine powder mixed with 2% chlorhexidine (0.06 g) or 10% doxycycline (0.30 g) in its liquid or liquid alone was placed to fill each well. Plates were incubated at 37°C as required for microbial growth. A blinded, independent observer measured zones of inhibition. The data were analyzed using independent “t” test to compare the differences among the three cement preparations for different micro-organisms.

Results:

All Biodentine samples inhibited microbial growth. The highest mean diameters of zone of inhibition for all the micro-organisms were found around Biodentine/chlorhexidine (13.417) followed by Biodentine alone (12.236) and Biodentine/doxycycline (11.25).

Conclusion:

In conclusion, adding 2% chlorhexidine gluconate in liquid of Biodentine enhanced the antimicrobial activity of Biodentine against all the tested micro-organisms except Candida albicans, while addition of 10% doxycycline decreased the antimicrobial activity of Biodentine. The differences were significant statistically (P < 0.05).

Confocal laser scanning microscopic investigation of ultrasonic, sonic, and rotary sealer placement techniques

Background:

Sealers are used to attain an impervious seal between the core material and root canal walls.

Aim:

To compare the depth and percentage of sealer penetration with three different placement techniques using confocal laser scanning microscopy as the evaluative tool.

Materials and Methods:

Root canals of 30 single-rooted teeth were prepared to a size of F3 and AH plus sealer with Rhodamine B was applied with Ultlrasonic file (Gr-1), lentulospiral (Gr-2), and Endoactivator (Gr-3). Canals were obturated with gutta-percha. The roots were sectioned at the 3 and 6-mm levels from the apical foramen and were examined on a confocal microscope.

Results:

A statistical significant differences among Gr-1, Gr-2, and Gr-3 were found at the 3 and 6-mm level (P < 0.05; ANOVA-Tukey tests) for the depth and percentage of sealer penetration except for Gr-1 and Gr-2 at 3-mm level. Gr-1 showed maximum mean depth of penetration (810 μm) and maximum mean percentage of sealer penetration (64.5) while Gr-3 showed minimum mean depth of penetration (112.7 μm) and minimum mean percentage of sealer penetration (26.7).

Conclusion:

Depth and percentage of penetration of sealer is influenced by the type of placement technique and by the root canal level with penetration decreasing apically.

An in vivo comparative evaluation to determine the accuracy of working length between radiographic and electronic apex locators

BACKGROUND

An in vivo comparative evaluation to determine the accuracy of working length between radiographic and electronic apex locators.

AIM

The study was aimed at evaluating the accuracy of electronic apex locator, to determine the working length of root canal, and to compare it with the radiographic method of working length determination.

MATERIALS AND METHODS

A total of 20 teeth selected for the study had to go for extraction because of periodontal or orthodontic reasons. Access cavity was prepared and the clinical estimated working length (CEWL) was determined with 10-25 no. K-file. A radiograph was then taken for determining the radiographic estimated working length (REWL). For electronic measurement of root canal, a 10 no. K-file was advanced toward the apex until it reached a 0.5 mm short of apex as shown by the apex locator. After fixing the file with a light cured composite, the tooth was extracted, the tooth surface was then longitudinally grounded using straight fissure diamond bur until the root canal and the tip of the file were visible. The distance of file from the minor constriction was measured with help of stereomicroscope.

STATISTICAL ANALYSIS

The chi-square test was used for statistical analysis for this study.

RESULTS

The chi-square test where χ² = 21.034 with P = 0.000 indicated that a significant difference exists among the groups. The electronic method showed highest number of cases with the working length at the minor constrictor.

CONCLUSION

The electronic method for determining the working length of root canal was found to be more accurate than the radiographic method.

Relationship between sealing ability of Activ GP and Gutta Flow and methods of calcium hydroxide removal

Aim:

To evaluate the effect of method of calcium hydroxide intracanal dressing removal, on sealing ability of Gutta Flow and Activ GP.

Materials and Methods:

Seventy extracted mandibular premolars were sectioned at CEJ and canals were prepared with profile 4% rotary file till #40. Canals were filled with calcium hydroxide, coronally sealed with Cavit G and stored at 37°C. After 7 days, samples were divided on the basis of calcium hydroxide removal method (Master apical file, Navi Tip FX, and F File) and obturating material (Activ GP and Gutta Flow). Three coats of nail polish were applied except 2 mm around apical foramen and samples were immersed in India ink dye, sectioned, and observed under stereomicroscope for microleakage.

Results:

The results were statistically analyzed with one way ANOVA-F with Tukey HSD test with the null hypothesis set as 5%.

Conclusions:

The seal of the canal system was adversely impacted by residual calcium hydroxide when Activ GP and Gutta Flow were used as obturating material and the sealing ability of Activ GP and Gutta Flow was better when MAF was used for removal of calcium hydroxide than F file or Navi tip FX.

Effect of occlusal restoration on stresses around class V restoration interface: a finite-element study

BACKGROUND

Causes of failures in class V restorations have always been controversial until now, since the biomechanical aspects of these restorations have been understood.

AIMS AND OBJECTIVE

This study was aimed to verify the hypothesis that eccentric forces are the cause of cuspal flexure, which lead to excessive stresses at the periphery of a class V restoration, further it identifies the amount of the stress and the flexure increase in the presence of an occlusal restoration using different restorative materials to restore (both cervical and occlusal) along with their comparison with respect to amount of stresses around the cervical restorations.

MATERIALS AND METHODS

The study was done by modeling a mandibular first premolar which was sectioned bucco-lingually, in the NISA, EMRC II finite element software. A 100N eccentric load was applied on the tooth structure and stresses were observed at the peripheries of the class V restoration when it was restored with composite and with glass ionomer cement. The stresses were further analyzed in the presence of occlusal restorations with different materials and configurations.

RESULTS

It was seen that the stresses at the gingival wall interface in case of class V glass ionomer cement was more than that for composite. In the presence of an occlusal amalgam restoration, the cuspal flexure was more than that of occlusal composite and the stresses at the class V peripheries were also statistically significant.

CONCLUSION

It was suggested that lower modulus composites can flex with the tooth structure decreasing the bond failure and that the stresses are much lesser when there is absence of an occlusal restoration. Occlusal composite restorations reinforce the tooth structure and reduce the cuspal flexure as compared to silver amalgam.

Effect of cavity varnish and intermediate restorative material on coronal microleakage in endodontically treated tooth

AIM

Evaluation of microleakage in endodontically treated teeth that have been coronally sealed with eugenol and noneugenol containing zinc oxide cement, with and without the use of cavity varnish.

MATERIALS AND METHODS

The crowns of single rooted teeth were removed at the cementoenamel junction (CEJ) and the root canals were prepared and obturated with gutta-percha points and zinc oxide eugenol (ZOE) sealer using lateral condensation technique. The samples were randomly divided into four groups-group 1, coronal seal was obtained with ZOE cement; in group 2, three coats of cavity varnish followed with coronal seal of ZOE cement; in group 3, Litark a (noneugenol cement) was placed in the prepared cavity as in group 1; and in group 4, cavity varnish and Litark were placed instead of ZOE as in group 2. The specimens were immersed in 2% methylene blue dye and examined under traveling microscope for evidence of dye penetration of the material.

STATISTICAL ANALYSIS

In this study, Kruskal-Wallis test, Mann-Whitney U, and Wilcoxon W tests were used.

RESULTS

Kruskal-Wallis test with P=0.000 indicated that a significant difference exists between the four groups. Mann-Whitney U test and Wilcoxon W test showed a significant difference at 0.05 levels as follows: group 1 with group 3 and 4, group 2 with group 3 and 4, and group 3 with group 4. There was no significant difference at 0.05 levels between group 1 and group 2.

CONCLUSION

Group 4 showed significant less amount of dye penetration as compared with other groups.

Effect of sealers on fracture resistance of endodontically treated teeth with and without smear layer removal: An in vitro study

Aim:

The present study involved the in vitro comparison of root reinforcing abilities of two sealers, i.e., Ketac-Endo and Acroseal, in endodontically treated teeth in the presence and absence of smear layer.

Materials and Methods:

Fifty teeth were taken and sectioned at the cementoenamel junction. The teeth with faults were discarded and a total of 36 teeth were used for study. The samples were biomechanically prepared using step-back technique. In 10 teeth, the smear layer was preserved using sodium hypochlorite. Smear layers were removed from 10 teeth using 17% EDTA, and in another 10 samples, the smear layers were eliminated using 17% EGTA. The remaining samples served as controls. Samples were obturated with sealers using the lateral condensation technique. Ketac-Endo (3M) is a glass ionomer based root canal sealer, and Acroseal (Septodont) sealers were used. The teeth were then tested by using an Instron testing machine.

Results:

Ketac-Endo shows higher fracture resistance values in comparison to Acroseal. Other factors as the amount of tooth structure remaining, the agents used for the removal of smear layer and instrumentation techniques may alter the tooth resistance to fracture.

Conclusion:

Ketac-Endo shows higher fracture resistance values in comparison to Acroseal.