Effects of charcoal-based whitening toothpastes on human enamel in terms of color, surface roughness, and microhardness: an in vitro study.

OBJECTIVE: Charcoal based oral care products have gained popularity in the last few years. The aim of this in vitro study was to compare the effects of different charcoal based whitening toothpastes on color, surface roughness and microhardness of human enamel. MATERIALS AND METHODS: Forty-eight specimens obtained from human permanent upper incisor teeth were randomly divided into 4 groups(n=12):Group-1:Colgate Total 12(CT); Group-2:Body Kingdom(BK); Group-3:Black is White(BW), Group-4:Colgate optic white(COW). Following 4 days cycle of darkening(2-min chlorhexidine and 60-min black tea per day), a 12- week brushing(twice daily for 1 min)was performed. Color of specimens was measured using a spectrophotometer. A contact type profilometer was used to measure surface roughness (Ra) and Vicker's hardness tester was used for the changes in microhardness(VHN). A representative sample from each group was visualized by SEM. Data were analyzed by One-way ANOVA, Welch, Fisher's, Kruskall-Wallis, Wilcoxon Sign Rank and Paired t-tests(p<0.05). RESULTS: After 12- week brushing, no differences were found among the groups in terms of color change(p=0.989). All toothpastes tested showed no clinically acceptable whitening performances. A substantial increase in surface roughness was found in all groups, except BW(p<0.05). An increase was found in microhardness with CT(p=0.013), while no changes were found with BK, BW and COW(p>0.05).Only few scratches were observed on the enamel surfaces by SEM evaluations. CONCLUSION: Twelve week brushing with charcoal based whitening toothpastes and a regular fluoridated toothpaste presented similar effects in color of enamel. Surface roughness was increased(except BW) while microhardness was not affected(except CT) with charcoal based whitening toothpastes. CLINICAL RELEVANCE: Charcoal based whitening toothpastes do not promise to whiten the human permanent teeth and their effects on enamel abrasion should not be disregarded.

Effect of bleaching agents on sealing properties of different intraorifice barriers and root filling materials.

OBJECTIVE: To evaluate the effect of intracoronal bleaching agents on the sealing properties of different intraorifice barriers and root filling materials. STUDY DESIGN: The root canals of extracted human premolars (n=180) were prepared by using System GT rotary files and filled with either gutta-percha+AH Plus or Resilon+Epiphany sealer. In both groups, the coronal 3mm of root filling was removed and replaced with one of the following materials applied as intraorifice barriers (n=30/group): 1. ProProot-MTA; 2. Conventional Glass ionomer cement; and 3. Hybrid resin composite. In each subgroup, intracoronal bleaching was performed using either sodium perborate with distilled water or 35% hydrogen peroxide gel for 3 weeks. The leakage of specimens was measured using fluid-filtration and dye penetration tests. The data were analyzed statistically with One-way ANOVA, Repeated Measures t-test and Independent Samples t-test (p=0.05). RESULTS: The fluid conductance values of the test groups were not influenced by the type of the bleaching agent, the intraorifice barrier, or the root filling material (all p>0.05). However, the extent of dye leakage was significantly affected by the type of intraorifice barrier material (p<0.05), which showed the following statistical ranking: glass ionomer cement > resin composite > ProRoot-MTA (p<0.05). CONCLUSIONS: The effect of 35% hydrogen peroxide gel or sodium perborate/distilled water on the sealing properties of tested intraorifice barriers and root filling materials varied conforming leakage assessment. These properties were not affected by using fluid filtration test, while the glass ionomer barrier showed the greatest amount of dye leakage in both gutta-percha and Resilon root-filled teeth.

Sealing properties of different obturation systems applied over apically fractured rotary nickel-titanium files.

This study investigated the sealing properties of cold laterally compacted gutta percha and Thermafil applied over different apically fractured rotary nickel-titanium files. Extracted human premolars were prepared by using ProTaper (Dentsply-Maillefer, Ballaigues, Switzerland) or ProFile (Dentsply-Maillefer) systems (n = 40 for each), after which half of the specimens in each subgroup were subjected to instrument separation at the apical level. For each rotary system, roots with and without apically separated instruments (n = 10 for each) were filled with the two obturation systems and the levels of fluid conductance were recorded. In the absence of instrument separation, the leakage of Thermafil (Dentsply Maillefer) was significantly less than that achieved with cold lateral compaction (p < 0.05), whereas Thermafil yielded similar amounts of leakage in roots prepared with the ProTaper and ProFile systems (p < 0.05). Roots with fractured ProTaper instruments displayed significantly less leakage than those filled without ProTaper fragments, regardless of the obturation technique used (p < 0.05). However, intracanal separation of ProFile instruments increased the leakage (p < 0.05), but the obturation method did not influence fluid conduction (p > 0.05). These results reveal the variability of leakage associated with apically fractured ProFile and ProTaper files and different obturation methods used.

Ultramorphological and histochemical changes after ER,CR:YSGG laser irradiation and two different irrigation regimes.

The purpose of this study was to evaluate the ultramorphological and chemical changes in Er,Cr:YSGG laser-treated radicular dentin in comparison with two different irrigation regimes. Extracted human premolars were assigned into three experimental groups. Group 1: After each file size, root canals were irrigated with 5.25% NaOCL, followed by a final irrigation with 5.25% NaOCL. Group 2: At each file size, biomechanical preparation was performed in conjunction with Rc-Prep, followed by 5.25% NaOCL irrigation; and 5.25% NaOCL for the final flush. Group 3: 5.25% NaOCL was used after each file size, followed by Er,Cr:YSGG laser irradiation; and a final flush with 5.25% NaOCL. Scanning electron microscopic (SEM) evaluations revealed failure of smear removal in NaOCL-irrigated specimens. RC-Prep + NaOCL-treated dentin revealed moderate-to-total presence of the smear layer with distinct areas of exposed collagen. Er,Cr:YSGG laser irradiation of radicular dentin also resulted in partial or total removal of the smear associated with a few small regions of thermal injury, including carbonization and partial melting. Energy dispersive X-ray analysis (SEM-EDX) showed no significant difference between the Ca/P ratios of the test groups, suggesting absence of changes at the molecular level.

Retreatability of Root Canals Obturated Using Gutta-Percha with Bioceramic, MTA and Resin-Based Sealers.

INTRODUCTION: The aim of this study was to evaluate the retreatability of root canals obturated with gutta-percha (GP) and three different endodontic sealers [iRoot SP (bioceramic sealer), MTA Fillapex (MTA-based sealer) and AH-26 (epoxy resin-based sealer)] using the ProTaper Universal Retreatment (PTR) system. METHODS AND MATERIALS: Forty extracted single-rooted human teeth were prepared with universal ProTaper files up to F4 (40/0.06). Specimens were randomly divided into four groups according to obturation technique/material: single-cone GP/AH-26, lateral compaction of GP/AH-26, single-cone GP/iRoot SP, and single-cone GP/MTA Fillapex. Root fillings were removed with PTR. The time taken to reach the working-length (TWL) was recorded. Roots were longitudinally sectioned and each half was evaluated using a stereomicroscope. Three observers scored each third of all specimen. Obtained data were analyzed using the Kruskal-Wallis, Mann-Whitney U, Welch and Games-Howell tests. The level of significance was set at 0.05. RESULTS: In single-cone GP/MTA Fillapex group the TWL was significantly shorter. The remnant of filling material in the apical and middle thirds of groups was similar and higher than the coronal thirds. CONCLUSION: None of the tested sealers were completely removed from the root canal system.

Fracture resistance of endodontically treated premolars restored with ormocer and packable composite.

In this study, mesiodistocclusal (MOD) cavity preparations of endodontically treated maxillary premolars that were enlarged to size #50 were restored using three restorative materials (one ormocer, one packable composite, and one high-copper amalgam) and two application techniques (with or without coronal radicular technique). Copper rings were filled with self-curing polymethylmethacrylate resin and the teeth were placed into resin up to the level of the CEJ. The teeth were grouped according to the restorative material and technique, mounted in a Universal Testing Machine, and the buccal walls subjected to a slowly increasing compressive force until fracture occurred. The force of fracture of the walls of each tooth was recorded and the results in the various groups compared. The group restored with packable composite without radicular extension showed the highest resistance to fracture (p < 0.05). Both groups restored with amalgam were significantly weaker than all the other groups (p < 0.05).

Effect of EDTA, sodium hypochlorite, and chlorhexidine gluconate with or without surface modifiers on dentin microhardness.

INTRODUCTION: This study aimed to evaluate the effects of root canal irrigants on the microhardness of root canal dentin in the presence and absence of surface-modifying agents. METHODS: Forty-eight root halves were prepared by longitudinal splitting of the distal roots of 24 freshly extracted mandibular human third molars and embedded in autopolymerizing acrylic resin, leaving the dentin surface exposed. After polishing, the microhardness values of the untreated dentin surfaces were recorded by using Vickers tester at the mid-root level. The root halves were randomly assigned to 6 groups composed of 8 samples each and treated for 5 minutes with one of the following irrigants: 17% EDTA, REDTA, 2% chlorhexidine gluconate (CHX), 2% CHX with surface modifiers (CHX-Plus), 6% NaOCl, or 6% NaOCl with surface modifiers (Chlor-XTRA). After surface treatment, dentin microhardness values were recorded at close proximity to the initial indentation areas. Experimental data were statistically analyzed by using the t test and one-way analysis of variance, followed by Tukey honestly significant difference test at α = 0.05. RESULTS: EDTA, REDTA, NaOCl, and Chlor-XTRA significantly decreased the microhardness of root dentin compared with intact controls (P < .05). CONCLUSIONS: The addition of surface modifiers to the irrigants did not affect the microhardness of the samples.

The importance of soft tissue examination in post-traumatic decision-making: a case report.

Dental and facial traumas involving teeth and supporting tissues are common sports-related injuries. In this case report treatment of a 23-year-old student who had been elbowed by an opponent player during a basketball game, which caused oblique fractures on both maxillary incisor teeth is presented. The patient presented 17 days following trauma having completed full recovery of soft tissues. A fragment of upper incisor tooth had been embedded in lower lip at the time of trauma, which was covered by healing tissues. At the 1 month control the patient complained of a hard structure in his lower lip. The elusive broken fragment was revealed by a radiograph and then removed surgically. This case report is a good example of the importance of the training of general dentists about sports-related traumatic injuries as well as emphasising the importance of the use of mouthguards during contact sports.

Debris and irrigant extrusion potential of 2 rotary systems and irrigation needles.

The purpose of this study was to compare the amount of apically extruded irrigant using 2 Ni-Ti rotary systems. Forty mandibular premolars with single canals were randomly assigned into 4 groups. Flower arrangement foam cubes were weighed with a precision balance before being attached to the apical portions of all teeth. In group 1, preparation was completed with ProTaper files. In group 2 canals were prepared with RaCe files. In groups 1 and 2, the irrigant was delivered with a 30-gauge conventional dental needle. In groups 3 and 4, teeth were prepared as in groups 1 and 2 with the exception that the irrigant was delivered with a side-vented irrigation needle. The weight of the extruded material (irrigant and debris) for each group was calculated by comparing the pre- and postinstrumentation weights of the foams used for periapical modeling. Obtained data were analyzed by Kruskal-Wallis and Mann-Whitney U tests, with P equals .05 as the level for statistical significance. ProTaper files used with regular needle irrigation had the highest fluid extrusion. The lowest irrigant extrusion was observed with the RaCe system combined with a side-vented irrigation needle. Within the limitations of this study, it can be concluded that irrigation needle and rotary instruments have an effect on the amount of extruded root canal irrigant.

Effect of different intraorifice barriers on the fracture resistance of roots obturated with Resilon or gutta-percha.

INTRODUCTION: This study investigated and compared the root reinforcement potential of 3 different intraorifice barriers (mineral trioxide aggregate [MTA], resin-modified glass ionomer cement [Vitremer], and fiber-reinforced composite [FRC]) placed over root canals obturated with gutta-percha or Resilon. METHODS: Crowns of 80 extracted human mandibular premolars were sectioned off to obtain 14-mm-long root specimens. After preparation of root canals with nickel-titanium rotary files, the roots were obturated with either the Resilon/Epiphany system or gutta-percha + AH Plus sealer. In both obturation groups, specimens were further subgrouped with respect to the intraorifice barrier material placed after removal of 3-mm coronal portion of the root fillings: (1) MTA, (2) Vitremer, and (3) FRC. The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. Results were evaluated statistically with two-way analysis of variance and Tukey tests. RESULTS: Fracture resistance of roots was significantly affected by the type of intraorifice barrier (P < .05), but not by the type of obturation system used (P > .05). CONCLUSIONS: The use of Vitremer and FRC significantly improved the fracture resistance, whereas MTA did not exhibit any reinforcing effect as an intraorifice barrier.

Management of a perforating internal resorptive defect with mineral trioxide aggregate: a case report.

INTRODUCTION: A radicular perforation caused by an inflammatory internal root resorption was present in a maxillary lateral incisor. METHODS: The root canal preparation was completed with hand files and thorough irrigation. Calcium hydroxide was placed as a temporary dressing for 10 days. At the second visit, the root canal with resorption lacuna was filled with warm vertical compaction of gutta-percha. The coronal access was restored with composite resin. A surgical flap was elevated to repair the resorption defect with gray mineral trioxide aggregate. The bony defect adjacent to the perforated lesion was filled with Unigraft (Unicare Biomedical, Laguna Hills, CA). RESULTS: The tooth was in function with satisfactory clinical and radiographic results after 48 months. CONCLUSIONS: According to the long term results of this case, successful sealing of a perforating defect is possible with mineral trioxide aggregate.

The effect of master point taper on bond strength and apical sealing ability of different root canal sealers.

OBJECTIVE: The aim of this study was to compare the bond strength and apical sealing ability of master gutta-percha points with different tapers, as used in conjunction with different root canal sealers. STUDY DESIGN: Roots of extracted human maxillary incisors (n = 135) were prepared with 0.06-taper nickel-titanium rotary files to final size 30. The roots were then randomly divided into 3 groups according to the root canal sealer used: 1) AH Plus; 2) Ketac-Endo; and 3) EndoREZ. Each sealer was combined with 1 of the following obturation techniques: 0.02-tapered gutta-percha master cone using lateral condensation, 0.04-tapered gutta-percha master cone using lateral condensation, or 0.06-tapered gutta-percha as a single cone. The bond strength and apical sealing ability were measured with the push-out test and dye penetration test, respectively. The data were statistically analyzed by using Kruskal-Wallis test with Bonferroni correction at P = .05. RESULTS: Both the taper of the gutta-percha point and root canal sealers had significant effects on push-out bond strength (P < .001). According to the microleakage data, AH Plus exhibited significantly lower overall leakage, whereas no difference was found between master cone points (P = .093). CONCLUSIONS: The use of matched-taper gutta-percha points in canals prepared with tapered rotary instruments may be advocated to improve bond strength ability of root canal filling material. Furthermore, AH Plus may be preferable to EndoRez and Ketac-Endo in terms of improved sealing and bonding quality of filling material.