Comparative assessment of nanosized intracanal medicaments on penetration and fracture resistance of root dentin - An in vitro study.

Context: The antimicrobial potential of conventional medicaments is reduced due to their limited permeability. The use of calcium hydroxide (CH) is known to reduce the root strength. Nano intracanal medicaments have the following advantages over conventional such as higher surface area and chemical reactivity, and due to its nanosize, have better penetrability, supporting its possible use as an intracanal medicament. Nano versions of CH, chitosan (CS), CS + CH, curcumin (T), and its conventional forms are used in our study. Aim: The aim of this study was to evaluate and compare the depth of penetration of nanosized intracanal medicaments and their effect on fracture resistance of root dentin. Materials and Methods: Eighty extracted single-rooted teeth were used after decoronation. Canals were enlarged up to size 30 (0.04° taper) using Neoendo instruments (Orikam, India). Teeth were randomly assigned to two broad groups based on the type of intracanal medicament used; Group A: control (conventional) (n = 40) and Group B: nanosized intracanal medicaments (n = 40). Each group was subdivided into four experimental groups (n = 10), Group A1: CH, Group A2: CS, Group A3: curcumin (T), Group A4: CS + CH, Group B1: nano calcium hydroxide (NCH), Group B2: nano CS (NCS), Group B3: nano curcumin (NT), and Group B4: NCS + nano calcium hydroxide (NCS + NCH). All the specimens were stored in a humidor at 37°C for 4 weeks. Out of 10 specimens from each group, five specimens were used for evaluating the depth of penetration using a confocal laser scanning electron microscope, and the remaining five specimens were used for evaluating fracture resistance in a universal testing machine at the end of 4 weeks. Data were analyzed using one-way ANOVA and intergroup comparison using Tukey's post hoc multiple comparison test. Results: The highest fracture resistance was seen with NCS and the maximum depth of penetration with nano calcium hydroxide (NCH). Conclusion: The fracture resistance and depth of penetration at a 4-week interval were higher in nano forms compared to their micro-sized counterparts with all groups. The coronal section presented the highest depth of penetration of intracanal medicaments followed by the middle and least in the apical section of root dentin with all groups.

The effect of bulk-fill composites: Activa and Smart Dentin Replacement on cuspal deflection in endodontically treated teeth with different access cavity designs.

Aim: The aim was to evaluate the effect of bulk-fill composites - Activa and Smart Dentin Replacement (SDR) on cuspal deflection in endodontically treated teeth with different access cavity designs. Materials and Methods: Forty-two maxillary first premolar teeth were randomly divided into three experimental groups based on different access designs as Group I - conservative endodontic cavities (CECs), Group II - traditional endodontic cavities, and Group III - CECs with diverging walls and two subgroups, based on the different access cavity restorations subgroup A-Activa and subgroup B-SDR with n = 7 per group. Root canal treatment was completed under the dental operating microscope. Cuspal deflection was assessed by measuring the distance between the glass beads using an optical microscope and micrometer immediately after a Root canal treatment and final measurements after access restorations. Data were statistically analyzed and tabulated. Results: Results showed that the access cavity restored with Activa showed the highest cuspal deflection than SDR in all the groups (P < 0.05). Conservative access designs showed the least cuspal deflection among other groups. Conclusion: CEC designs showed lesser cuspal deflection than traditional endodontic cavity designs. SDR can be considered as a choice of material for access restorations.

Effect of silver diamine fluoride, potassium iodide, and glutathione on micro-shear bond strength of glass ionomer cement to caries affected dentine.

Background: Silver diamine fluoride (SDF, 38%) is an efficient topical fluoride used to arrest dental caries though it causes black staining of both teeth and restoration. The application of potassium iodide (KI) after SDF reduces the stain, but the color change is only temporary. An alternative method suggested is by mixing glutathione (GSH) with SDF, which preserves the silver ions of SDF within the solution. Hence, the purpose of this in vitro study was to evaluate the microshear bond strength (µSBS) of glass ionomer cement (GIC) to caries affected dentin (CAD) pretreated with SDF/KI/GSH. Materials and Methods: Thirty dentine slices of 2 mm thickness from human permanent upper premolars were demineralized using pH cycling method to mimic CAD. They were allocated to three groups of 10 each and treated with SDF, SDF-KI (SDF followed by KI), SDF + GSH (SDF mixed with GSH), respectively. Specimens were bonded with GICs. The µSBS was assessed using a universal testing machine and the data obtained were analyzed using one-way ANOVA and Tukey's post hoc test. Results: The µSBS (mean ± standard deviation) values for groups SDF, SDF-KI, and SDF + GSH were 4.81 ± 2.026, 5.78 ± 1.809, 8.18 ± 2.828 megapascal respectively. Group 3 showed significantly better bond strength compared to groups 1 and 2. In group 2, the addition of KI showed better bond strength when compared to group 1, but the difference was not statistically significant. Conclusion: Pretreatment of teeth with GSH along with SDF application showed significantly better bond strength of GIC to CAD compared to SDF and SDF-KI.

Is odontogenic keratocyst an endodontic enigma? A rare case report of management of odontogenic keratocyst in anterior mandible.

Odontogenic keratocyst (OKC), a rare, locally aggressive developmental cyst, is found incidentally on dental radiographs, most commonly in the posterior mandible. When it occurs in the periapical region in association with nonresponding teeth to pulp sensibility tests, it is often misdiagnosed as other endodontic lesions such as radicular cyst, lateral periodontal cyst and dentigerous cyst. This case report describes the rare occurrence of OKC in the anterior mandibular region managed successfully with endodontic treatment and re-interventional surgery in a conservative approach. This case report also emphasizes on the importance of histopathological examination of the surgically excised tissue specimens as the clinical, radiographic and histopathological correlations are essential for successful treatment.

Effect of conventional irrigation and photoactivated disinfection on Enterococcus faecalis in root canals: An in vitro study.

AIMS: A study was done to evaluate the antimicrobial efficacy of sodium hypochlorite (NaOCl) and photoactivated disinfection (PAD) on Enterococcus faecalis. SETTINGS AND DESIGN: Random sampling, in-vitro study. SUBJECTS AND METHODS: Access opening and biomechanical preparation were performed on fifty freshly extracted mandibular second premolars. The specimens were sterilized; 15 µm of E. faecalis was inoculated into each canal and incubated at 36°C for 24 h. Later, specimens were randomly divided into two groups of fifty each and following procedures was carried out: (i) conventional irrigation with 2.25% NaOCl (ii) PAD using diode laser, and toluidine blue photosensitizer. Samples were collected from each canal using sterile paper points which were deposited in brain heart infusion broth, and microbiological evaluation was carried out. STATISTICAL ANALYSIS USED: Student's t-test was used to find the significant difference in the reduction of colony forming unit (CFU) between the groups. RESULTS: The mean CFUs of the two groups showed statistically significant difference (P = 0.001). Improved antibacterial efficacy was seen with PAD group compared to conventional NAOCL irrigation. CONCLUSIONS: NaOCl alone was not effective in eliminating E. faecalis completely from the root canals. PAD compared to conventional irrigation showed the best results in removing E. faecalis from root canals.

The Comparative Evaluation of Antibacterial Activity of Methacryloxydodecyl Pyridinium Bromide and Non-methacryloxydodecyl Pyridinium Bromide Dentin Bonding Systems Using Two Different Techniques: An In vitro Study.

BACKGROUND: Adhesive systems have enabled clinicians to preserve more tooth structure by changing cavity designs. However, because of the polymerization shrinkage adhesive systems are not capable of totally prohibiting the gap formation between the cavity and restorative material of composite resin leading to colonization of oral microorganisms from saliva. One possible solution for this serious problem is to use dental materials with antibacterial properties. So the development of such agents has initiated for successful restorations. Hence, the purpose of this study was to compare the antibacterial activities of two dentin bonding systems: Clearfil protect bond (CPB) and prime & bond NT using agar well technique and tooth cavity model. MATERIALS AND METHODS: CPB and prime and bond NT (PBNT) were evaluated in this study using agar well technique and tooth cavity model. In the agar well technique, the materials were filled in the wells of Muller-Hinton agar plates inoculated with Streptococcus mutans NCTC 10449M and the diameter of inhibition zones produced around the materials were measured after 24 h of incubation. For the tooth cavity model test, 3 cavities (of diameter - 1 mm and depth - 2 mm) were prepared in the flat occlusal dentin of human extracted molar. After sterilization, the teeth were left in the culture of broth of S. mutans at 37°C for 72 h for allowing bacteria to invade the cavity for 72 h. The dentin bonding systems were applied separately to each of the two infected cavities, and the third cavity was not applied and used as control. After sealing the occlusal surfaces, the teeth were kept in sterile physiological saline at 37°C for 72 h. The standardized amounts of dentin chips (120 + 5 mg) were obtained from the cavity walls, and the numbers of bacteria recovered were determined. The results were analyzed using one-way ANOVA, Kruskal-Wallis and Mann-Whitney's U-tests. RESULTS: The primer of CPB and PBNT produced similar inhibition zones (P > 0.05), but the bonding resin of CPB did not produce any inhibition. When tested by the tooth cavity model technique, the application of CPB resulted in significantly less bacterial recovery than the PBNT (P < 0.05), demonstrating substantial antibacterial effects. CONCLUSION: The CPB that employs the antibacterial primer containing methacryloxydodecyl pyridinium bromide, was effective in inactivating the bacteria in the cavity compared to little antibacterial activity shown by PBNT. The tooth cavity mode test used in the present study is a reliable method to evaluate the antibacterial effects of dentin bonding agents simulating clinical situations.

Endodontic treatment of mandibular canine with two roots and two canals.

In majority of cases, mandibular canines have one root and one root canal, although 15% may have two canals. Literature report shows incidence of two-rooted canine as low as 1.7%. This article reports a clinical case of endodontic treatment of mandibular canine with two roots and two canals.