Effect of Citric Acid Versus EDTA on Radiographic Root Development in Regenerative Endodontic Treatment: An Animal Study.

INTRODUCTION: Regenerative endodontic treatment was introduced with the aim of reinforcing the root and enabling further root development. In the process of dentin mineralization, bioactive molecules are entrapped in the dentin matrix, which can be released later by rinsing the dentin with chelating agents. This study aimed to compare the effects of citric acid and EDTA on radiographic root development in regenerative endodontic treatment in an animal model. METHODS: Premolars of 3 beagle dogs were used in this study. The teeth at 1 side of the jaw were irrigated with EDTA according to the regeneration protocol of the American Association of Endodontists. The teeth in the other quadrant were irrigated with citric acid in the second treatment session. Follow-up radiographs were obtained at 6 months, and the primary and final data were analyzed in SPSS Version 23 (IBM Corp, Armonk, NY) using the analysis of covariance. RESULTS: There was no significant difference between the 2 irrigating solutions regarding the increase in root length (P = .668); however, EDTA showed significantly superior efficacy in increasing the root dentin thickness compared with citric acid (P = .022). CONCLUSIONS: Within the limitations of this study, the use of citric acid versus EDTA was not superior on radiographic root development in regenerative endodontic treatment.

Effects of Erbium:Yttrium-Aluminum-Garnet Laser Irradiation on Bovine Dentin Contaminated by Cariogenic Bacteria.

Objective: This study was performed to determine the bactericidal effects of erbium:yttrium-aluminum-garnet (Er:YAG) laser irradiation and the morphological and chemical composition changes in bovine dentin. Methods: Dentin slabs were prepared from bovine incisors, and then cultured with Streptococcus mutans to produce bacteria-infected dentin samples. The samples were randomly divided into five groups with Er:YAG laser irradiation energy densities of 0, 6.37, 12.73, 19.11, and 25.47 J/cm2. After irradiation, samples were stained and observed by confocal laser scanning microscopy. The bactericidal abilities were measured using live/dead staining. The morphology and chemical components were investigated by scanning electron microscopy and energy-dispersive spectrometry. Results: After irradiation, the elimination of bacteria and the smear layer were significantly better in the high energy density groups (19.11, 25.47 J/cm2) than in the low energy density groups (6.37, 12.73 J/cm2; p < 0.001). On morphological examination, the group with minimum energy density (6.37 J/cm2) showed superficial melting. In the high energy density groups (12.73, 19.11, and 25.47 J/cm2), laser-irradiated dentin showed a clean surface with open orifices. Significant increases were observed in the weight percentages of calcium (from 19.75 ± 0.69 to 34.47 ± 2.91, p < 0.001) and phosphate (from 8.58 ± 0.43 to 15.10 ± 1.81, p < 0.001), whereas significant decreases were observed for oxygen (from 49.84 ± 0.69 to 36.39 ± 2.86, p < 0.001) and carbon (from 26.06 ± 3.58 to 12.80 ± 2.26, p < 0.01) with increasing energy density. Conclusions: This study confirmed that Er:YAG laser irradiation has bactericidal and dentin conditioning effects.

Protection Against Discolouration by Two Over-the Counter Desensitising Products.

PURPOSE: To determine in vitro the protection potential against discolouration of two OTC (over-the-counter) desensitising products on enamel and dentin in comparison to a standard toothpaste and water by means of a spectrophotometer. MATERIALS AND METHODS: A total of 96 samples of bovine enamel-dentin complex and 48 of bovine dentin were alternatively immersed in red wine, tea, coffee or water after having been treated by a sodium monofluorophosphate- and calcium phosphate-based product (Curodont Protect), an amine fluoride-based toothpaste (Elmex Red), a stannous chloride-based toothpaste (Elmex Protection Erosion) or distilled water (negative control). Initial (T0) and final colour (T1, after 4 weeks of immersion in staining solutions) of each specimen were assessed by a spectrophotometer. Statistical analysis was done by means of repeated measures ANOVA followed by Fisher's LSD post-hoc test. Differences between T0 and T1 were considered stastistically significant at p ≤ 0.05. RESULTS: When enamel samples were measured over a black background, ΔE00 values (T0-T1) varied from 2.2 (SD 0.7) for amine fluoride-based product/water to 53.9 (SD 7.6) for amine fluoride-based-product/red wine. When dentin samples were measured over a black background, ΔE00 values (T0-T1) varied from 5.4 (SD 0.9) stannous chloride based product/water to 61.6 (SD 3.7) amine fluoride-based product/red wine. CONCLUSION: Specifically, the application of the sodium monofluorophosphate was able to statistically significantly (p ≤ 0.05) reduce discolouration induced by the staining solutions tested only on the enamel-dentin complex, while distilled water and the stannous fluoride-based product were able to statistically significantly (p ≤ 0.05) reduce discolouration induced by the staining solutions tested in pure dentin samples.

Imaging human teeth by phosphorus magnetic resonance with nuclear Overhauser enhancement.

Three-dimensional phosphorus MR images ((31)P MRI) of teeth are obtained at a nominal resolution of 0.5 mm in less than 15 minutes using acquisition pulse sequences sensitive to ultra-short transversal relaxation times. The images directly reflect the spatially resolved phosphorus content of mineral tissue in dentin and enamel; they show a lack of signal from pulp tissue and reduced signal from de-mineralized carious lesions. We demonstrate for the first time that the signal in (31)P MR images of mineralized tissue is enhanced by a (1)H-(31)P nuclear Overhauser effect (NOE). Using teeth as a model for imaging mineralized human tissue, graded differences in signal enhancement are observed that correlate well with known mineral content. From solid-state NMR experiments we conclude that the NOE is facilitated by spin diffusion and that the NOE difference can be assigned to a higher water content and a different micro-structure of dentin. Thus, a novel method for imaging mineral content without ionizing radiation is proposed. This method has potential use in the assessment of de-mineralization states in humans, such as caries of teeth and osteoporosis of bones.

Sodium Thiosulfate for Recovery of Bond Strength to Dentin Treated with Sodium Hypochlorite.

INTRODUCTION: The aim of this study was to evaluate the efficacy of sodium thiosulfate (Na2S2O3) for restoring adhesion to pulp chamber dentin treated with sodium hypochlorite (NaOCl) and EDTA. METHODS: Sixty-three crowns of bovine incisors were cut to expose the dentin pulp chamber. The specimens were polished and randomly distributed into 9 groups (n = 7) according to the following protocols used: 0.9% sodium chloride for 30 minutes (negative control), 5.25% NaOCl for 30 minutes, 17% EDTA for 3 minutes, and 5.25% NaOCl for 1 minute (positive control). The other groups, after treatments with NaOCl and EDTA, were immersed in 0.5% or 5% Na2S2O3 for 1, 5, and 10 minutes or just immersed in an inert solution for 10 minutes (0.9% sodium chloride). After drying the specimens, Scotchbond Multi-Purpose (3M ESPE, St Paul, MN) was applied to the pulp chamber dentin followed by Filtek Z250 composite (3M ESPE). Six rectangular slabs were obtained from each specimen, and the dentin/resin interface was tested by using a universal testing machine. The resulting data were submitted to 1-way analysis of variance and the Duncan test (P = .05). RESULTS: There was a significant decrease in bond strength regarding NaOCl and EDTA (P < .05). When 5% Na2S2O3 was used for 10 minutes, the bond strength was found to be statistically equal to the negative control and higher than the positive control (P < .05). CONCLUSIONS: The use of Na2S2O3 can significantly increase the bond strength of composite resin to NaOCl/EDTA-treated dentin, allowing adhesive restorations to be immediately applied after endodontic treatment.

Comparative study of radiopacity of resin-based and glass ionomer-based bulk-fill restoratives using digital radiography.

This study investigated the radiopacity values of glass ionomer- and resin-based bulk-fill restoratives of different thicknesses using digital radiography. Two glass ionomer-based and three resin-based bulk-fill restoratives, and a conventional composite were studied. Five disc-shaped specimens were prepared from each of these materials at three different thicknesses; specimens of enamel and dentin with the same thicknesses were also prepared. Materials were placed over a complementary metal oxide-semiconductor sensor together with the tooth specimen and an aluminum step-wedge, and then exposed using a dental X-ray unit. The images were analyzed using a software program to measure the mean gray values (MGVs), which were converted to equivalent aluminum thicknesses. Two-way ANOVA was used to investigate the significance of differences among the groups. The GCP Glass Fill specimens showed the lowest radiopacity values, and the Quixfil specimens had the highest values. All materials had higher radiopacity values than enamel and dentin, except for GCP Glass Fill, which had a radiopacity similar to that of enamel. The resin-based bulk-fill restoratives had significantly higher radiopacity values than glass ionomer-based restoratives. All of the tested materials showed radiopacity values higher than that of dentin, as recommended by the ISO.

Comparison of different dentin pretreatment protocols on the bond strength of glass fiber post using self-etching adhesive.

INTRODUCTION: This study compared the influence of different irrigants with and without ultrasound or laser irradiation on the bond strength of glass fiber posts using a self-etching adhesive in a supplementary dentin pretreatment. METHODS: Ninety bovine incisor roots were divided into 3 groups according to the irrigant tested: 2% chlorhexidine (CHX) (n = 30); 2.5% sodium hypochlorite (NaOCl) (n = 30), and saline solution (control) (n = 30). Each group was randomly divided into 3 subgroups according to the supplementary dentin pretreatment: ultrasound, Nd:YAG laser, and nonsupplemented (control). A self-etching adhesive system (Futurabond DC; VOCO GmbH, Cuxhaven, Germany) was used, and the glass fiber posts were cemented with dual-cure epoxy-based luting agent (Bifix QM, VOCO GmbH). All roots were sectioned transversely, and the push-out test was performed. Failure mode analysis was also evaluated. RESULTS: Bond strength decreased significantly after the use of 2.5% NaOCl in all root thirds (P < .05). CHX showed no difference in the mean bond strength value compared with saline solution (P > .05). The supplementary dentin pretreatment using the Nd:YAG laser or ultrasound did not improve the bond strength values for both NaOCl and CHX (P > .05). Moreover, the apical third exhibited the lowest mean bond strength values (P < .05). Analysis indicated that the predominant failure mode was the mixed type. CONCLUSIONS: Regardless of the irrigant used, the supplementary dentin pretreatment with ultrasound or laser irradiation showed no improvement in bond strength. Also, the use of NaOCl decreased the bond strength of glass fiber posts using a self-etching adhesive system, whereas CHX preserved it.

Clinical and radiographic outcomes of traumatized immature permanent necrotic teeth after revascularization/revitalization therapy.

INTRODUCTION: Revascularization treatment is rapidly becoming an accepted treatment alternative for the management of endodontic pathology in immature permanent teeth with necrotic dental pulps. However, the success and timing of clinical resolution of symptoms, and radiographic outcomes of interest, such as continued hard tissue deposition within the root, are largely unknown. METHODS: In this prospective cohort study, 20 teeth were treated with a standardized revascularization treatment protocol and monitored for clinical and radiographic changes for 1 year. Standardized radiographs were collected at regular intervals, and radiographic changes were quantified. RESULTS: All 20 treated teeth survived during the 12-month follow-up period, and all 20 also met the clinical criteria for success at 12 months. As a group, the treated teeth showed a statistically significant increase in radiographic root width and length and a decrease in apical diameter, although the changes in many cases were quite small (such that the clinical significance is unclear). The within-case percent change in apical diameter after 3 months was 16% and had increased to 79% by 12 months, with 55% (11/20) showing complete apical closure. The within-case percent change in root length averaged less than 1% at 3 months and increased to 5% at 12 months. The within-case percent change in root thickness averaged 3% at 3 months and 21% at 12 months. CONCLUSIONS: Although clinical success was highly predictable with this procedure, clinically meaningful radiographic root thickening and lengthening are less predictable after 1-year of follow-up. Apical closure is the most consistent radiographic finding.

Technical quality of root canal treatment of posterior teeth after rotary or hand preparation by fifth year undergraduate students, The University of Jordan.

The aim of this study was to investigate the technical quality of root canal treatment provided by the undergraduate students as their first experience in molar endodontics using nickel-titanium (NiTi) files in a crown-down approach compared with stainless steel standard technique. This study was carried out by the fifth year undergraduate students attending peer review sessions as a part of their training programme, using two different questionnaires to assess the overall technical quality and potential problems regarding endodontic complications after root canal preparation with these two techniques. The overall results indicated a statistically significant difference in the performance of the two instrument techniques in difficult cases showing better performance of the NiTi system and mean rotary preparation time (P < 0.001). Under the conditions of this study, novice dental students, using NiTi ProTaper rotary files, were able to prepare root canals faster with more preparation accuracy compared with canals of same teeth prepared with hand instruments.

Ultrasound imagery for dental implant diagnosis and treatment planning in a porcine model.

STATEMENT OF PROBLEM: Currently, there is no commercially available method to provide non-invasive, non-ionizing, real-time imaging of the gingival form and bony architecture of implant sites, before, during, and after implant placement. PURPOSE: The purpose of this study was to demonstrate the feasibility of 2-dimensional (2-D) ultrasound imaging of soft and hard tissues for implant diagnosis and treatment planning. MATERIAL AND METHODS: A sector scanning ultrasound system was applied. Five representative clinical features (implant in an edentulous ridge, single implant tooth replacement, implant dehiscence, tooth dehiscence, and mental foramina) were created or identified in each of the 5 porcine jaws, which were then covered with soft tissue and imaged in an acoustic water tank. RESULTS: All of the 5 model features, in all 5 jaws, were clearly visible with the ultrasound. Most objects were visible over a large range of positions and angles. Each of the features, as well as the soft tissue and bone surfaces, were recognized by specific acoustic signatures, with the same signature recurring for each object type among all 5 of the jaw specimens. All implants were highly reflective and clearly visualized. CONCLUSIONS: A 2-D sector scanning ultrasound system was demonstrated to be capable of imaging representative features for implant treatment planning in a porcine model; these included implants placed in edentulous ridges; implants placed for single tooth replacement; implants with simulated dehiscences; teeth with simulated dehiscences; and mental foramina. Specific acoustic signatures for these features were defined. Qualitative differences between ultrasound and other dental imaging techniques were described.

Assessment of enamel-dentin caries lesions detection using bitewing PSP digital images.

OBJECTIVES: The aim of this study was to evaluate the detection of enamel-dentin occlusal caries using photostimulable phosphor plates. MATERIAL AND METHODS: The ability to detect enamel-dentin occlusal caries in 607 premolars and molars from 47 patients between 10 and 18 years old, referred to the School of Dentistry of the Federal University of Bahia, Brazil, was evaluated based on clinical and radiographic examinations, using the criteria proposed in a previous study. A total of 156 bitewing digital images were obtained using Digora® (Soredex Medical Systems, Helsinki, Finland) phosphor plates. The plates were scanned and the images were captured and displayed on a computer screen. Image evaluation was done using Digora® for Windows 2.1 software, Soredex®. The radiologists were allowed to use enhancement tools to obtain better visibility during scoring of the teeth based on the radiographic criteria proposed in a previous study. Descriptive analysis and chi-squared proportion tests were done at 5% significance level. RESULTS: The results of clinical examination showed a higher prevalence of teeth with a straight dark line or demineralization of the occlusal fissure (score 1) and a lower prevalence of sealed teeth (score 5). In the bitewing digital images, 47 teeth presented visible radiolucency, circumscribed, in dentin under occlusal enamel (enamel-dentin caries lesions). CONCLUSIONS: Correlating the clinical and radiographic findings, it was found that in the majority of teeth diagnosed by radiographic images as having enamel-dentin caries, no caries could be detected by clinical examination.

Laser-induced fluorescence and X-ray spectral analysis of carious process in hard dental tissues.

Morphological and spectral X-ray analysis of carious and noncarious extracted teeth showed the patterns of dentin ossification in caries of different degree. Parietal ectopic ossification of the canal and cavity lumens in stages III and IV dental caries is regarded as a specific structural marker of pathological regeneration. The X-ray spectral analysis showed that the progress of carious process is paralleled by loss of mineral components. Laser-induced fluorescent study of tissues in extracted teeth showed 4 spectral bands corresponding to mineral and protein components of the tooth. The progress of carious process was associated with reduction of the fluorescence intensities of the spectral bands characteristic of dental collagen and mineral components.

Comparison of conventional, rotary, and ultrasonic preparation, different final irrigation regimens, and 2 sealers in primary molar root canal therapy.

PURPOSE: The aim of this study was to compare the shaping effectiveness rotary nickel-titanium (Profile .04 ISO), ultrasonic (K-Type/Satelec), and stainless-steel hand file (K-file/Maillefer) instrumentation and to assess tubular penetration of 2 gutta percha sealers (AH Plus and Sealite-Ultra) following 4 different final irrigation regimens in primary molar roots. METHODS: Distal roots of extracted human primary second molars were prepared with 1 of the 3 instrumentation techniques. Direct digital radiographs were obtained on a custom-made platform before and after instrumentations. The amount of dentin removal, canal transportation, centering of preparation, changes in root curvature and working length, and zip formation were evaluated using image analysis. RESULTS: While no significant differences were found between the 3 preparation techniques in regards to dentin removal (P > .05), ultrasonic instrumentation significantly increased the incidence of zip formation (P < .05) and decreased working length (P < .05). Following final irrigation with 2.5% sodium hypochlorite (NaOCL), 10% ethylenediaminetetraacetic acid (EDTA), 17% EDTA, or distilled water (control), tubular penetration of the tested sealers were investigated under scanning electron microscope. Use of AH Plus after 17% EDTA irrigation exhibited the best tubular penetration. CONCLUSIONS: Root canal preparation with Profile .04 ISO nickel titanium instruments can be a viable alternative to manual instrumentation in primary teeth. When used as a gutta percha sealer, AH Plus exhibits good tubular penetration when 17% EDTA is used for final flush.

Cariogenic changes in dental enamel of boys and girls in relation to salivary properties. II. Radiological examination.

In earlier clinical studies of a group of children subjected to an intense fluoride treatment programme several salivary properties were related to cariogenic changes in the enamel surface, as assessed by mirror and probe. In this study the relationship between salivary parameters and cariogenic changes was investigated on bitewings taken from the same teeth. Inverse correlations were found between the acid producing capacity of the micro-organisms in the saliva (as determined in the Snyder test) and most cariogenic changes detected in bitewings particularly in boys. These radiologically detected changes in enamel were the reverse of those obtained clinically. These discrepancies were explained by differences in sensitivity between clinical and radiological techniques used to diagnose cariogenic changes. In contrast it was confirmed radiologically that for girls the P concentration in saliva and for boys the amount of resting saliva are important for preventing extension of caries into deeper layers of enamel.