Shear bond strengths of bur or Er:YAG laser prepared dentine to composite resin with or without low-level laser conditioning: an in vitro study.

This study aims to compare the different modes of cavity preparation while evaluating the effect of low-level laser therapy (LLLT) on dentine before bonding in terms of shear bond strength between composite resin and dentine. Fifty human molar teeth were mounted on acrylic blocks and dentine specimen were prepared after which they were randomized into four equal groups. Cavity preparation mode differed in respective groups. After etching, bonding; composite resin was placed and polymerized on the prepared dentine surfaces. The specimens were kept in an environment simulating oral cavity and then shear tested in a universal testing machine. The failure surfaces of the specimen teeth were subjected to SEM micrographic evaluation. The cavity prepared with diamond abrasive points had a higher shearing load at failure that was statistically significantly different from the ones prepared with laser. That with diamond abrasive points followed by LLLT of the cavity surface with Nd:YAG laser had a higher bond strength than the ones prepared with just Er:YAG laser and there was no statistically significant difference between these and the ones prepared with diamond abrasive points alone. SEM analysis of the failure mode in bur-cut dentine showed the presence of a hybrid layer at the interface. Surface conditioning of the same with Nd:YAG laser before etching suggested a recrystallisation of dentine due to the heat produced. Cavity preparation with Er:YAG laser leads to reduced shear bond strength to adhesive restorative materials when compared with that using burs and high-speed handpiece.

Comparative evaluation of different irrigating and irrigant activation system in removal of gutta-percha/sealer during retreatment: An in vitro Micro-CT study.

Background: The aim of the study was to compare the efficacy of different irrigation and irrigant activation system used as an adjuvant to retreatment rotary files in removal of gutta-percha and sealer from endodontic retreatment using Micro-CT. Method: 64 extracted permanent maxillary central incisor teeth with single canal, were collected and decoronated to standard length of 16 mm. Instrumentation was done using rotary files and obturation was performed using GuttaCore and AH plus sealer. After setting of sealer, initial removal of filling material was performed using ProTaper universal retreatment files (D1, D2, D3). All 64 sample were randomised into four groups (n = 16) Group1: Endodontic syringe irrigation, Group 2: Passive Ultasonic Irrigation (PUI), Group 3: EndoActivator, and Group 4: EndoVac. Micro-CT scanning was performed after obturation, initial removal of filling material by retreatment file and after using experimental protocols of each group, and volume of remaining filling material was calculated using Dolphin software. Statistical analysis performed with one-way ANOVA followed by Tukey's post hoc. Results: A significant reduction in the volume of residual obturation material were found between each group. PUI was superior to the sonic (EndoActivator), negative pressure irrigation technique (EndoVac) and positive pressure irrigation at the coronal, middle third and apical third of the root canal. However, none of the supplementary techniques were able to completely remove the residual obturation material. Conclusion: PUI and EndoActivator were found better in remaining filling material removal, demonstrating clinically useful as supplementary technique in removing remaining obturation material during endodontic retreatment.

Comparative evaluation of remineralizing effect of fluoride and nonfluoride agents on artificially induced caries using different advanced imaging techniques.

Aim: The aim of the study is to evaluate and compare the in-vitro remineralization efficacy of remineralizing agents, i.e., fluoride-free toothpaste, fluoride toothpaste, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), CPP-amorphous calcium fluoride phosphate (CPP ACFP), and silver diamine fluoride (SDF) paste on dentine over time. Methodology: Seventy-five extracted human permanent molars were selected. The buccal section of these samples was shaped into a slab. Artificial caries was induced by dipping the samples into the demineralizing solution (pH 4.5) for 21 days. They were then divided into five groups (n = 15). Each experimental group underwent one of the following treatments: Group 1 - Fluoride-free toothpaste (negative control), Group 2 - Fluoride toothpaste (positive control), Group 3 - CPP-ACP, Group 4 - CPP-Amorphous Calcium fluoride Phosphate and Group 5 - SDF. Postremineralizing treatment, Scanning electron microscope, Energy dispersive X-ray and Quantitative light induced fluorescence imaging were carried out to analyze the remineralizing efficacy. The data obtained was then subjected to statistical analysis using ANOVA and Paired t-tests. Results: It was seen that SDF showed highest remineralization efficacy followed by CPP-amorphous calcium fluoride phosphate, CPP-ACP, fluoride toothpaste and fluoride-free toothpaste. The difference in mean value among the groups was statistically significant (P < 0.001). Conclusion: SDF showed the highest remineralizing potential in scanning electron microscopy and energy dispersive X-ray, followed by CPP-ACFP, CPP-ACP, Fluoride toothpaste, and Fluoride-free toothpaste. Quantitative light fluorescence analysis showed more fluorescence changes in the CPP-ACFP followed by CPP-ACP, Fluoride toothpaste, and Fluoride-free toothpaste.

Stereomicroscopic Evaluation of Microcrack Formation in Dentin by ProTaper Next, Revo S, and WaveOne Gold File System.

BACKGROUND: During the biomechanical preparation of the root canal by rotary file systems, stress is generated within the canal, which leads to dentinal microcrack formation. Such defects are evaluated only under the microscope. AIM: The present study aimed to evaluate dentinal microcrack formation after instrumentation with ProTaper Next (M-wire), Revo S (conventional NiTi), and WaveOne Gold (Gold-wire) file systems under the stereomicroscope. MATERIALS AND METHODS: Forty single-rooted teeth free from any defect were selected and divided into four groups (Control, PTN, RS, and WOG). Experimental groups were instrumented with file system used in the study, and the control group were left unprepared. Samples were further decoronated and sectioned at 3 mm, 6 mm, and 9 mm from the apex perpendicular to the long axis and examined under a stereomicroscope at ×25 for different types of microcracks (no fracture, complete fracture, partial fracture, and other fracture). STATISTICAL ANALYSIS USED: Data analysis was done by the Chi-square test using the SPSS version 17.0 software. A two-sided (α = 2) P < 0.05 (P < 0.05) was considered statistically significant. RESULTS: The null hypothesis was rejected. There was a statistically significant difference between the groups. All file systems created microcracks in the root dentin. WOG group showed an incidence of 66.7% for no fracture, PTN group had 40% for other fracture, and RS group had 60% for complete fracture. CONCLUSION: Single file system WOG with gold wire technology proves to be the best choice for canal preparation among the tested groups in terms of least dentinal crack formation.

A randomized controlled trial of endodontic treatment using ultrasonic irrigation and laser activated irrigation to evaluate healing in chronic apical periodontitis.

BACKGROUND: Aim of this trial was to evaluate the combined clinical and radiographic success rate of endodontic treatment using passive ultrasonic irrigation (PUI) and laser activated irrigation (LAI) as compared to conventional syringe irrigation. MATERIAL AND METHODS: Permanent incisors and single rooted premolars were assessed for eligibility and 69 patients were randomly divided into three treatment groups (n=23) by allocation concealment method and irrigation was performed in accordance with the allocated group. Teeth were evaluated clinically and radiographically with CBCT after 6 months and 12 months of the treatment. RESULTS: A significant difference was observed in the radiographic healing rates among three groups (χ2=12.29, p=0.05). On comparing the final outcome among the three groups (n=19), it was found that 2 (10.5%) cases of group I(Conventional Syringe irrigation), 7 (36.8%) cases of group II (Passive ultrasonic irrigation) and 8 (42.1%) cases of group III(Laser activated irrigation) were healed while under healing category 13 (68.4%) cases of group I, 12 (63.2%) cases of group II and 11 (57.9%) of group III were observed whereas 4 (21.1%) cases were categorised as diseased in group I only. CONCLUSIONS: LAI and PUI can increase the predictability of the endodontic treatment success in cases of chronic apical periodontitis. Key words:Cone-beam computed tomography, CBCT-PAI, Irrigation, LASER, Radiographic healing, Root canal treatment, Ultrasonic.

A relative assessment of essential oil of Chrysopogon zizanioides and Matricaria chamomilla along with calcium hydroxide and chlorhexidine gel against Enterococcus faecalis in ex vivo root canal models.

OBJECTIVE: The objective of this study was to evaluate the antibacterial efficacy of two doses of vetiver and chamomile essential oils compared with chlorhexidine and calcium hydroxide against Enterococcus faecalis. MATERIALS AND METHODS: The growth inhibition and minimum inhibitory concentration of all tested materials were determined ex vivo following agar diffusion and broth dilution assay procedure. Human maxillary anterior teeth were prepared with protaper rotary files, followed by incubation with standard broth of E. faecalis. A total of 140 teeth were included in the study. These teeth are randomized and equally divided into seven groups and were treated with low (1.25 µl) and high doses (2.5 µl) of essential oils of vetiver and chamomile and calcium hydroxide (0.1/1.0 mL), 2% chlorhexidine (2.5 µl). Microbial sampling of six teeth from each group was done with paper points and Gates-Glidden burs at 1, 7, and 14 days and colony-forming unit (CFU)/mL was determined. RESULTS: There was a significant reduction in mean ± standard deviation of CFU (log10) in vetiver oil high dose (3.32 ± 0.036) and chlorhexidine (3.34 ± 0.030), followed by calcium hydroxide (3.46 ± 0.015) and chamomile oil high dose (3.48 ± 0.20) on day 1. On 7th day, a significant reduction was seen in chlorhexidine (2.74 ± 0.212), chamomile oil (2.81 ± 0.035, low dose and 2.97 ± 0.119, high dose), followed by calcium hydroxide (3.25 ± 0.028). However, on 14th day, it was 2.32 ± 0.088 for chlorhexidine, 2.91 ± 0.029 for chamomile oil high dose, 3.15 ± 0.010 for vetiver oil high dose, and 3.09 ± 0.068 for calcium hydroxide. CONCLUSION: The study showed a good effectiveness of chamomile oils in root canal infection of E. faecalis at different time intervals compared to chlorhexidine and calcium hydroxide vetiver oil did not sustain their activity for a longer duration.

Depth and percentage of resin-based sealer penetration inside the dentinal tubules using EndoVac, EndoActivator, Navi tip FX irrigation system: A confocal laser scanning microscope study.

AIM: This in vitro study was conducted to evaluate the effect of EndoVac, EndoActivator, and Navy Tip FX irrigation system on lateral depth and percentage of sealer penetration into the dentinal tubules using confocal laser scanning microscope. MATERIALS AND METHODS: Forty recently extracted single-rooted mandibular premolars were taken and root canal treatment was performed using three different irrigation system, that is, EndoVac, EndoActivator, and Navi tip FX. The samples were divided into 4 groups according to the irrigation system used: Control or conventional needle (Group I), Navi Tip FX (Group II), EndoActivator (Group III), and EndoVac (Group IV). All teeth were obturated using AH Plus sealer labeled with fluorescent rhodamine B dye. The teeth were sectioned at coronal (5 mm), middle (3 mm), and apical 3rd (1 mm) from the apex. Total percentage and maximum depth of sealer penetration were measured using confocal laser scanning microscopy. The data were evaluated statistically using Kruskal-Wallis test with a 95% confidence level (P = 0.01). RESULTS: EndoVac resulted in more sealer penetration then EndoActivator and Navi Tip FX irrigation system. Endoactivator resulted in more sealer penetration in comparison to Navi Tip FX. CONCLUSION: Percentage and depth of sealer penetration were more at apical and middle 3rd with Endovac system followed by Endoactivator and Navi tip FX system.

Comparative evaluation of antibacterial effect of nanoparticles and lasers against Endodontic Microbiota: An in vitro study.

BACKGROUND: Present study was conducted with the aim of evaluating antimicrobial efficacy of silver (AgNP) and gold nanoparticles (AuNP) with and without Nd: YAG laser (L) irradiation against experimentally inoculated Enterococcus faecalis in infected human root dentin. MATERIAL AND METHODS: 120 extracted single rooted human teeth were prepared and inoculated with E. faecalis for 24 hrs. The teeth were then randomly divided into 4 experimental group: AgNPs group: irrigation for 3minutes with 50 µl of 100 ppm, the AuNPs group: irrigation with 50 µl of 100 ppm, the AgNPs & Nd: YAG lasers group: irrigation with 50 µl of 100 ppm + irradiation with 1.5W laser for 60 seconds, the AuNPs & Nd: YAG lasers group: irrigation with 50 µl of 100 ppm + irradiation with 1.5W laser for 60 seconds. One control group consisting of 2% CHX irrigation for 3 minutes was also there (n = 20). The specimens were collected from the canal before and after irrigation, and colony forming units were observed. RESULTS: Significant difference was found among all the groups in comparison to the control group (p<0.05). The greatest reduction in CFU's was observed with combination of AgNPs & Nd: YAG lasers group. CONCLUSIONS: AgNPs in combination with Nd: YAG laser irradiation has the potential to be used as root canal disinfectant. Key words:Antibacterial efficacy, gold, silver, nanoparticles, lasers, solid-state.

An ex vivo evaluation of effect of dentin pretreatment with various agents for varying time intervals on the shear bond strength of resin.

BACKGROUND: This article highlights the contribution of collagen structure/stability to the bond strength. We hypothesize that induction of cross-linking in dentin collagen fibrils improves dentin collagen stability and thus bond strength with composite also improves. AIMS: The aim of the study was to evaluate the effect of collagen cross-linking agents on the shear bond strength of composite resins. SUBJECTS AND METHODS: One hundred human permanent teeth were randomly divided into three groups: Group I (n = 20) - no dentin pretreatment done, Group II - dentin pretreatment with 10% sodium ascorbate for 5 min (IIa) and 10 min (IIb), and Group III - dentin pretreatment with 6.5% proanthocyanidin (PA) for 5 min (IIIa) and 10 min (IIIb). A composite resin was bonded on prepared surfaces and cured. Thermocycling was done, and shear bond strength of the prepared samples was tested using a universal testing machine. RESULTS: Values of Group I (control) were lowest whereas that of Group II (sodium ascorbate) were highest. The following order of shear bond strength was observed: IIb > IIa > IIIb ~ IIIa > I. Results for sodium ascorbate were found to be time dependent, whereas for PA, differences were nonsignificant. CONCLUSIONS: Treatment of dentinal surfaces with collagen cross-linking agent increases the shear bond strengths.

An Invitro Evaluation of Antimicrobial Efficacy and Flow Characteristics for AH Plus, MTA Fillapex, CRCS and Gutta Flow 2 Root Canal Sealer.

INTRODUCTION: Cleaning and shaping of root canal does not guarantee complete disinfection of the canal, regardless of the systems and techniques used for this purpose. Therefore, it becomes mandatory for the endodontic filling materials to have a good antimicrobial potential especially against E. faecalis. This research was aimed therefore to evaluate the antibacterial efficacy and flow properties of different root canal sealers. AIM: To study invitro antimicrobial activity and flow characteristics for Resin based (AH Plus), Mineral Trioxide Aggregate based (MTA Fillapex), Calcium hydroxide based (CRCS) and Flowable Gutta-Percha (Gutta Flow 2) endodontic sealers on Enterococcus faecalis. MATERIALS AND METHODS: Enterococcus faecalis ATCC 29212 was used to test antibacterial potential of sealers by Agar diffusion test (ADT) and Direct Contact Test (DCT). ADT was performed by punching the sealers on a well of 4×6mm diameter on Muller Hinton agar plates. These plates were inoculated with standard suspension of E. faecalis and the zone of inhibition was measured at 24 hours and after 7 days. All the sealers were prepared in accordance with the manufacturer's recommendations. Flow of sealers was measured according to ADA specification no. 57. RESULTS: All sealers showed antibacterial activity against E. faecalis except Gutta Flow 2. At 24 hours, zone of inhibition was highest in Calcibiotic Root Canal Sealer (CRCS) and lowest in AH Plus. After 7 days the zone of inhibition decreased in AH plus, CRCS and MTA Fillapex. DCT showed a significant lower number of organisms in AH Plus, CRCS and MTA than controls at both the time intervals. Gutta Flow 2 did not show any significant antimicrobial action. Maximum and minimum flow was shown by AH Plus and CRCS respectively. CONCLUSION: Highest microbial inhibition was shown by (CRCS), followed by MTA Fillapex and AH Plus. Gutta Flow 2 did not show any inhibition of E. faecalis by ADT. Maximum reduction in antibacterial property with time against E. faecalis was seen with AH Plus. Maximum flow was shown by AH Plus and minimum by CRCS.

Accidental aspiration/ingestion of foreign bodies in dentistry: A clinical and legal perspective.

The potential of foreign body aspiration or ingestion is a worldwide health problem in dentistry. The general dental practitioners should be extremely attentive in handling of minor instruments during any intervention related to the oral cavity, especially in the supine or semi-recumbent position of the patient. Aspiration cases are usually more critical and less common than ingestion. We report a case of iatrogenic aspiration of an endodontic broach, which gets disclosed during the recording of past dental history of the patient. The patient was asymptomatic during that time. A quick posterior-anterior chest radiograph was taken which revealed the presence of broach in the lower lobe of the left lung. The patient was immediately referred to the pulmonary medicine department where the fiberoptic bronchoscope retrieval was planned, and the same was carried out successfully under local anesthesia. Although such accidents have rare occurrence, the associated risks and morbidity are too high to be overlooked, especially from the viewpoint of special care, resources, and the associated financial cost required for their management. Moreover, practitioners are also liable for malpractice litigation given the fact that such cases are avoidable. This article also discusses relevant review literature, risk factors, symptoms, and management of such iatrogenic accidents along with drawing attention to the significance of preventive measures and their role in avoiding meritorious legal and ethical issues.

Analysis of micro-shear bond strength of self-etch adhesive systems with dentine: An in vitro study.

BACKGROUND: Success or failure of a composite restoration largely depends on its bonding to enamel/dentine. Several better adhesive systems have been developed during the last few years due to rapid advancement in the technology. Recent self-etched adhesives have fewer clinical steps and are less technique sensitive. METHODS: Ninety extracted human permanent molars were collected, grounded and finished to prepare flat dentine-bonding surfaces on their occlusal surface. All specimens were divided into three groups (n = 30) on the basis of three adhesive systems Adper Easy Bond (AE), Beautibond (BB) and Xeno IV (XE). These adhesive systems were applied on prepared mid-dentine-bonding surface. A restorative resin was added with the help of a transparent tube of 2 mm height and 1.7 mm internal diameter and cured. Fifteen specimens in each group were loaded to failure in an Instron Universal Testing Machine after storage for 24 h at 37 °C to check micro-shear bond strength. Another fifteen specimens from each group were thermocycled 500 times at 5 °C and 55 °C with dwell time of 1 min in each bath followed by loading to failure. The data obtained was analyzed with SPSS version 21 at significance level of <05. RESULTS: After 24 h, micro-shear bond strength of BB was higher (26.04 MPa) than XE (23.69 MPa) and AE (21.50 MPa). After thermocycling, micro-shear bond strength decreased significantly in BB (P = .001) and XE (P = .03). CONCLUSION: The micro-shear bond strength of BB was highest among three groups, which decreased after thermocycling.

Management of mucosal fenestration with external root resorption by multidisciplinary approach.

Mucosal fenestration is a clinical condition in which the overlying gingiva is denuded and the root is exposed to the oral cavity. Invasive cervical resorption is an entirely uncommon entity and its aetiology is poorly understood. This case presents an invasive cervical resorption of maxillary right central incisor with fenestration at the cervical third of the tooth. The resorption area was chemomechanically debrided. It was then restored with Mineral Trioxide Aggregate over which pink glass ionomer cement (GC Fuji VII) was placed. Lateral pedicle flap was used to cover the fenestration. The resorptive defect was restored using tooth coloured restorative resin after removal of the pink glass ionomer cement. Orthodontic treatment was continued for correction of malocclusion.

A comparative evaluation of smear layer removal using two rotary instrument systems with ethylenediaminetetraacetic acid in different states: a SEM study.

AIM: The aim of the study was to evaluate the ability of 17% ethylenediaminetetraacetic acid (EDTA) solution and 19% EDTA gel to remove debris, and smear layer produced during root canal preparation with two NiTi files systems, Mtwo and Protaper. MATERIALS AND METHODS: Twenty freshly extracted human anterior teeth with single root canal were collected. The crowns were sectioned at the cemento-enamel junction, and working length was measured. These samples were randomly divided into four groups of five samples each. In each group, 2 ml of 3 % sodium hypochlorite solution was used with first instrument. The groupings were as follows. Group 1: 2 ml of 17% EDTA solution and 2 ml of 3% NaOCl were used alternatively each time a new file was employed. This group was prepared with Mtwo rotary files. Group 2: The samples in this group was prepared with Mtwo rotary files. EDTA gel (19%) was used and the samples were irrigated with 2 ml of 3% NaOCl. NaOCl and EDTA gel were used alternatively. Group 3: Five samples were prepared with Protaper file. Irrigation regime was the same as in Group 1. Group 4: Five samples were prepared with Protaper files and irrigation regime was the same as in Group 2. SEM study was done and the collected data were submitted for statistical analysis. RESULTS: There was no statistically significant difference with the varied instruments used (Mtwo and Protaper files), and 17% EDTA solution and 19% EDTA gel. CONCLUSION: Both the NITI instruments produced a similar dentin surface on root canal wall when used with EDTA gel and EDTA solution.