OBJECTIVES: The aim was to evaluate dentinal crack formation after root canal preparation with ProTaper Next system (PTN) with and without a glide path. MATERIALS AND METHODS: Forty-five mesial roots of mandibular first molars were selected. Fifteen teeth were left unprepared and served as controls. The experimental groups consist of mesiobuccal and mesiolingual root canals of remaining 30 teeth, which were divided into 2 groups (n = 15): Group PG/PTN, glide path was created with ProGlider (PG) and then canals were shaped with PTN system; Group PTN, glide path was not prepared and canals were shaped with PTN system only. All roots were sectioned perpendicular to the long axis at 1, 2, 3, 4, 6, and 8 mm from the apex, and the sections were observed under a stereomicroscope. The presence/absence of cracks was recorded. Data were analyzed with chi-square tests with Yates correction. RESULTS: There were no significant differences in crack formation between the PTN with and without glide path preparation. The incidence of cracks observed in PG/PTN and PTN groups was 17.8% and 28.9%, respectively. CONCLUSIONS: The creation of a glide path with ProGlider before ProTaper Next rotary system did not influence dentinal crack formation in root canals.
Axis, Cervical Vertebra ; Dental Pulp Cavity ; Dentin* ; Incidence ; Molar ; Root Canal Preparation ; Tooth

OBJECTIVES: This study evaluated the effects of intraradicular moisture on the pushout bond strength of a fibre post luted with several self-adhesive resin cements. MATERIALS AND METHODS: Endodontically treated root canals were treated with one of three luting cements: (1) RelyX U100, (2) Clearfil SA, and (3) G-Cem. Roots were then divided into four subgroups according to the moisture condition tested: (I) dry: excess water removed with paper points followed by dehydration with 95% ethanol, (II) normal moisture: canals blot-dried with paper points until appearing dry, (III) moist: canals dried by low vacuum using a Luer adapter, and (IV) wet: canals remained totally flooded. Two 1-mm-thick slices were obtained from each root sample and bond strength was measured using a push-out test setup. The data were analysed using a two-way analysis of variance and the Bonferroni post hoc test with p = 0.05. RESULTS: Statistical analysis demonstrated that moisture levels had a significant effect on the bond strength of luting cements (p < 0.05), with the exception of G-Cem. RelyX U100 displayed the highest bond strength under moist conditions (III). Clearfil SA had the highest bond strength under normal moisture conditions (II). Statistical ranking of bond strength values was as follows: RelyX U100 > Clearfil SA > G-Cem. CONCLUSIONS: The degree of residual moisture significantly affected the adhesion of luting cements to radicular dentine.
Dehydration ; Dental Pulp Cavity ; Dentin* ; Ethanol ; Nerve Fibers, Myelinated* ; Resin Cements* ; Vacuum ; Water

PURPOSE: This study evaluated the adhesion to acrylic resin specimens and biofilm formation capability of Candida albicans strains isolated from HIV positive subjects' oral rinse solutions. MATERIALS AND METHODS: The material tested was a heat-cured acrylic resin (Acron Duo). Using the adhesion and crystal violet assays, 14 oral Candida albicans isolated from HIV-positive subjects and 2 references Candida strains (C. albicans ATCC 90028 and C. albicans ATCC 90128) were compared for their biofilm production and adhesion properties to acrylic surfaces in vitro. RESULTS: There were no significant differences in adhesion (P=.52) and biofilm formation assays (P=.42) by statistical analysis with Mann-Whitney test. CONCLUSION: Denture stomatitis and increased prevalence of candidal carriage in HIV infected patients is unlikely to be related to the biofilm formation and adhesion abilities of C. albicans to acrylic resin materials.
Biofilms ; Candida albicans* ; Candida* ; Gentian Violet ; HIV* ; Humans ; Polymethyl Methacrylate ; Prevalence ; Stomatitis, Denture

OBJECTIVES: To determine the effect of size and insertion depth of irrigation needle on the amount of apical extruded debris and the amount of penetration depth of sealer using a confocal laser scanning microscope (CLSM). MATERIALS AND METHODS: Twenty maxillary premolars were assigned to 2 groups (n = 10), according to the size of needle tip, 28 G or 30 G. Buccal roots of samples were irrigated with respective needle type inserted 1 mm short of the working length (WL), while palatal roots were irrigated with respective needle type inserted 3 mm short of the WL. Prepared teeth were removed from the pre-weighed Eppendorf tubes. Canals were filled with F3 gutta-percha cone and rhodamine B dye-labeled AH 26 sealer. Teeth were transversally sectioned at 1 and 3 mm levels from the apex and observed under a CLSM. Eppendorf tubes were incubated to evaporate the irrigant and were weighed again. The difference between pre- and post-weights was calculated, and statistical evaluation was performed. RESULTS: Inserting needles closer to the apex and using needles with wider diameters were associated with significantly more debris extrusion (p < 0.05). The position of needles and level of sections had statistically significant effects on sealer penetration depth (p < 0.05 for both). CONCLUSIONS: Following preparation, inserting narrower needles compatible with the final apical diameter of the prepared root canal at 3 mm short of WL during final irrigation might prevent debris extrusion and improve sealer penetration in the apical third.
Bicuspid ; Dental Pulp Cavity ; Gutta-Percha ; Microscopy, Confocal ; Needles ; Rhodamines ; Tooth ; Tooth Apex

OBJECTIVES: The aim of this study was to investigate whether the diameter and direction of the plunger and simulation of the periodontal ligament (PDL) affected the stress distribution in endodontically treated premolars. METHODS: A fracture strength test was simulated via finite element analysis. A base model was set up, and the following parameters were modified: plunger diameter (3 mm vs. 6 mm), plunger direction (vertical vs. 135° angular to the central fossa), and PDL simulation. The analysis was conducted using the CosmosWorks structural analysis program, and the results are presented in terms of von Mises stresses. RESULTS: The smaller plunger increased the stresses at the contact area of the crown, but the plunger diameter had no effect on the stress distribution within the root. An angular plunger direction increased stresses within the root, as well as at the buccal cusp of the crown, compared with the vertical direction. Simulation of the PDL caused higher stress accumulation, especially in the cervical region of the root. CONCLUSIONS: The plunger diameter had no effect on the stress distribution in the roots, whereas the plunger direction and PDL simulation did affect the stress distribution. More stringent standards can be established by taking such parameters into account when performing fracture testing in future studies.
Bicuspid ; Crowns ; Endodontics ; Finite Element Analysis ; Periodontal Ligament ; Tooth

OBJECTIVES: This study compared the ability of several techniques to remove calcium hydroxide (CH) from the root canal and determined the influence of CH residues on the accuracy of the electronic apex locator. MATERIALS AND METHODS: Root canals of 90 human maxillary lateral incisors with confirmed true working length (TWL) were prepared and filled with CH. The teeth were randomly assigned to one of the experimental groups according to the CH removal technique (n = 14): 0.9% saline; 0.9% saline + master apical file (MAF); 17% ethylenediamine tetraacetic acid (EDTA); 17% EDTA + MAF; 5.25% sodium hypochlorite (NaOCl); 5.25% NaOCl + MAF. Six teeth were used as negative control. After CH removal, the electronic working length was measured using Root-ZX (Morita Corp.) and compared with TWL to evaluate Root-ZX accuracy. All specimens were sectioned longitudinally, and the area of remaining CH (CH) and total canal area were measured using imaging software. RESULTS: The EDTA + MAF and NaOCl + MAF groups showed better CH removal than other groups (p < 0.05). Root-ZX reliability to prevent overestimated working length to be > 85% within a tolerance of +/- 1.0 mm (p < 0.05). There was strong negative correlation between amount of CH residues and EAL accuracy (r = -0.800 for +/- 0.5 mm; r = -0.940 for +/- 1.0 mm). CONCLUSIONS: The mechanical instrumentation improves the CH removal of irrigation solutions although none of the techniques removed the dressing completely. Residues of CH medication in root canals affected the accuracy of Root-ZX adversely.
Bandages* ; Calcium Hydroxide* ; Dental Pulp Cavity ; Edetic Acid ; Humans ; Incisor ; Sodium Hypochlorite ; Tooth