Biomimetic approach to strengthen the incisal fracture composite build-up: an in vitro study.

OBJECTIVE: Incisal composite build-up shows a high failure susceptibility. The incorporation of fiber-reinforced composite (FRC) during composite restoration could improve its strength. Hence the study was planned to compare the effect of various positions of FRC on the strength of composite resin incisal build-ups. METHODS: In maxillary incisors (n = 90), 3 mm of the incisal edge was cut and teeth were categorized into three groups based on the location and number of fibers used during incisal composite build-up - Group I: composite resin; Group II: composite resin and a single fiber palatally and Group III: composite resin along with two fibers palatally. RESULTS: The data showed that group II had the maximum load-bearing values followed by group I and group III. CONCLUSION: Within the confines of our study, it can be concluded that the addition of FRC to the conventional incisal composite build-up increased the overall strength restoration. Such composite restoration reinforced with a single fiber on the palatal side showed the highest load-bearing capacity compared to two fibers reinforced and unreinforced composites. The common mode of failure in group I was in composite resin, in two fibers reinforced at fibers-composite junction, and in one fiber reinforced composite was in the remaining part of the tooth.

Comparative evaluation of effect of sodium hypochlorite and chlorhexidine in dental unit waterline on aerosolized bacteria generated during dental treatment.

BACKGROUND: In dentistry, nosocomial infection poses a great challenge to clinicians. The microbial contamination of water in dental unit waterlines (DUWLs) is ubiquitous. Such infected DUWLs can transmit oral microbes in the form of aerosols. Previous studies have suggested treating DUWLs with various disinfectants to reduce cross-contamination. The literature lacks a comparative evaluation of the effect of the use of 0.2% chlorhexidine (CHX) and 0.1% sodium hypochlorite (NaOCl) in DUWLs on aerosolized bacteria generated during dental procedures. OBJECTIVE: To compare the effect of NaOCl and CHX in DUWLs on aerosolized bacteria generated during restorative and endodontic procedures. MATERIALS AND METHODS: A total of 132 patients were equally divided into three groups (n = 44 in each group) according to the content of DUWL as follows. Group I-0.1% NaOCl Group II-0.2% CHX Group III-distilled water (Positive control) One-way ANOVA was performed and the Kruskal-Wallis test was used for intergroup comparison. RESULTS: For the restorative procedure, inter-group comparison of mean colony-forming units (CFU) scores showed a statistically significant difference between the groups (p - .001) with the score of group 3 higher than group 2 followed by group 1. For the endodontics, an inter-group comparison of CFU scores showed a statistically significant difference between the groups (p - .003) with the mean score in group 1 being the lowest and group 3 being the highest. CONCLUSION: The addition of NaOCl or CHX in DUWLs shows an effective reduction in aerosolized bacteria compared to distilled water.

Comparative evaluation of four different root canal irrigation techniques for apical extrusion of sodium hypochlorite - An in vitro study.

Objective: This study compared the potential for apical extrusion of sodium hypochlorite (NaOCl) when using needle irrigation (NI), passive ultrasonic irrigation (PUI), passive subsonic irrigation (PSI), and negative pressure system (NP). Materials and Methods: One hundred freshly extracted human permanent anterior teeth with complete root formation were embedded rigidly in agarose gel-containing cresol purple. Teeth were randomly allocated to six groups: G1-NI; G2-PUI; G3-PSI; G4-NP; G5-positive control; and G6-negative control. The chemomechanical preparation was completed and 12 ml of 3% NaOCl was delivered for 180 s in all groups. Dye diffusion was standardized by doing gel photography after the NaOCl final irrigation the Chi-square test and Kruskal-Wallis one-way analysis of variance test were used for the data analysis. Results: G1 had statistically significant apical extrusion compared to G2 (P = 0.001), G3 (P = 0.001), and G4 (P = 0.001) groups. G4 showed the least amount of apical extrusion. Conclusions: pH-sensitive gel model is useful in evaluating NaOCl extrusion. NP produced least NaOCl extrusion as compared to the other three systems. Due consideration should be given to the potential for apical extrusion of the irrigant before the selection of an irrigation system.

Effect of various single file systems on microcrack formation in root canals: Scanning electron microscope study.

BACKGROUND: The aim of this study was to compare dentinal crack formation in root canal walls following 3 single file systems with continuous rotation under a scanning electron microscope (SEM). MATERIALS AND METHODS: In this SEM study, seventy mandibular premolars were randomly divided into 5 groups. 3 experimental groups (n = 20) and 2 control groups (n = 5) as follows: Group I: Neolix NiTi file system, Group II: OneShape systems, Group III: OneCurve file system, positive control: conventional Hand File system, negative control: unprepared. After root canal preparations, the roots were sectioned at 3, 6, and 9 mm from the apex with water irrigation. The sections were inspected in all directions under SEM at × 100 magnification to determine the presence of cracks. The Chi-square test was used to analyze the data. There is a statistically significant difference in the crack formation between the apical third (P = 0.012) and coronal third (P = 0.002) when comparing all the 5 groups. No significant difference is found in the middle third (P = 0.46). P < 0.05 is considered statistically significant. RESULTS: Maximum cracks in the apical third were seen with One Shape file 11 (55%) and in the coronal third with Neolix NiTi 14 (70%). There is a statistically significant difference in the crack formation only in OneCurve when comparing the apical, middle, and coronal third for the individual group (P = 0.042). CONCLUSION: There was a significant difference in crack formation in apical and coronal third. OneCurve caused the least incidence of cracks when compared to other file systems. OneCurve file system can be a choice for canal preparation over Neolix Niti and OneShape.

Discovery of isoquinolinone and naphthyridinone-based inhibitors of poly(ADP-ribose) polymerase-1 (PARP1) as anticancer agents: Structure activity relationship and preclinical characterization.

The exploitation of GLU988 and LYS903 residues in PARP1 as targets to design isoquinolinone (I & II) and naphthyridinone (III) analogues is described. Compounds of structure I have good biochemical and cellular potency but suffered from inferior PK. Constraining the linear propylene linker of structure I into a cyclopentene ring (II) offered improved PK parameters, while maintaining potency for PARP1. Finally, to avoid potential issues that may arise from the presence of an anilinic moiety, the nitrogen substituent on the isoquinolinone ring was incorporated as part of the bicyclic ring. This afforded a naphthyridinone scaffold, as shown in structure III. Further optimization of naphthyridinone series led to identification of a novel and highly potent PARP1 inhibitor 34, which was further characterized as preclinical candidate molecule. Compound 34 is orally bioavailable and displayed favorable pharmacokinetic (PK) properties. Compound 34 demonstrated remarkable antitumor efficacy both as a single-agent as well as in combination with chemotherapeutic agents in the BRCA1 mutant MDA-MB-436 breast cancer xenograft model. Additionally, compound 34 also potentiated the effect of agents such as temozolomide in breast cancer, pancreatic cancer and Ewing's sarcoma models.

Evaluation of aromatherapy on success rate of inferior alveolar nerve block in teeth with irreversible pulpitis: a prospective randomized clinical trial.

OBJECTIVE: This prospective, block randomized clinical trial was conducted to evaluate the effect of aromatherapy on the success rate of inferior alveolar nerve block (IANB) in teeth with irreversible pulpitis. METHOD AND MATERIALS: In this clinical trial, 46 patients fulfilling the inclusion criteria were randomly divided into two equal groups: group I (n = 22) received IANB in a closed operatory without any fragrance, whereas group II (n = 24) received IANB in a separate closed operatory saturated with lavender fragrance using a candle warmer. The modified dental anxiety scale (MDAS) for anxiety and visual analog scale (VAS) for pain were recorded preoperatively as well as during access cavity preparation. For MDAS, a total score of more than 18 was considered as tremendously anxious or dental phobic. No or mild pain on VAS was considered as success. Data were analyzed using paired t test and independent sample t test. P < .05 was considered as statistically significant. RESULTS: Difference in mean VAS (P = .749) and MDAS (P = 1.000) between both the groups was statistically nonsignificant. However there was a statistically significant difference in mean VAS (P = .000) and MDAS (P = .001) during access opening. CONCLUSION: Lavender aromatherapy can be used successfully to alleviate dental anxiety as well as to increase the anesthetic success rate of IANB in teeth with irreversible pulpitis.

Discovery of Novel, Potent, Brain-Permeable, and Orally Efficacious Positive Allosteric Modulator of α7 Nicotinic Acetylcholine Receptor [4-(5-(4-Chlorophenyl)-4-methyl-2-propionylthiophen-3-yl)benzenesulfonamide]: Structure-Activity Relationship and Preclinical Characterization.

The discovery of a series of thiophenephenylsulfonamides as positive allosteric modulators (PAM) of α7 nicotinic acetylcholine receptor (α7 nAChR) is described. Optimization of this series led to identification of compound 28, a novel PAM of α7 nicotinic acetylcholine receptor (α7 nAChR). Compound 28 showed good in vitro potency, with pharmacokinetic profile across species with excellent brain penetration and residence time. Compound 28 robustly reversed the cognitive deficits in episodic/working memory in both time-delay and scopolamine-induced amnesia paradigms in the novel object and social recognition tasks, at very low dose levels. Additionally, compound 28 has shown excellent safety profile in phase 1 clinical trials and is being evaluated for efficacy and safety as monotherapy in patients with mild to moderate Alzheimer's disease.

Cone-Beam Computed Tomography-Guided Management of C-Shaped Type III Dens Invaginatus With Peri-invagination Periodontitis in a Maxillary Canine: A Case Report.

Dens invaginatus (DI) is a developmental anomaly seen infrequently in maxillary canines. This article describes cone-beam computed tomography-guided nonsurgical management of type III (subtype B) DI in a permanent maxillary canine associated with a sinus tract and peri-invagination periodontitis in a 17-year-old female. After gaining access to the root canal, thorough chemo-mechanical preparation was performed and usage of intracanal medicament of calcium hydroxide was prescribed for 3 weeks, during which the sinus tract healed completely. Obturation was completed by a technique of down-packing master-cone gutta-percha, followed by backfilling with thermoplasticized gutta-percha. At 12-months follow-up, the patient was asymptomatic with complete resolution of the sinus tract and radiographic evidence of healing of periapical pathology.

Endodontic management of a maxillary molar with formation supradentalis: A case report.

Anatomic variations may be observed in the crown or in the roots of maxillary molars. In rare instances, crown and root morphology, both show variations. Occurrence of paramolar cusp on the occlusal surface as central cusp or on the buccal surface as parastyle has been frequently reported in maxillary molars. However, presence of paramolar cusp on the palatal surface has not been reported. 'Formation supradentalis' is a condition in which supernumerary cusp is associated with a supernumerary root in a molar. The occurrence of such concomitant corono-radicular morphology is multifactorial, that is primary polygenic with secondary environmental influences. This case reports the diagnosis and endodontic management of Formation-supradentalis that had six cusps and four roots in the maxillary first molar. The tooth exhibited a prominent paramolar palatal cusp and cusp of Carabelli along with a supernumerary palatal root. To the best of author's knowledge, this is the first documentation of endodontic management of Formation supradentalis.