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The purposes of the study were to evaluate the bond strength of bioceramic TotalFill root repair material (RRM) in retrograde cavities prepared using Er:YAG and Er,Cr:YSGG laser and steel bur, and to analyze failure modes. The root canals of 30 single-rooted teeth were endodontically treated, their root-ends were resected using a diamond bur, and the teeth were randomly divided into three groups ( N  = 10) according to the retrograde cavity preparation technique: (1) Er:YAG laser, (2) Er,Cr:YSGG laser, and (3) steel bur. All retrograde cavities were filled with the TotalFill RRM which was prepared according to the manufacturers’ instructions. Push-out test was performed using universal testing machine, and failure mode was analyzed using a scanning electron microscope. The data were analyzed using one-way ANOVA, post hoc analysis with Bonferroni correction, and Fisher-Freeman-Halton exact test ( p  < 0.05). In the Er:YAG-, Er,Cr:YSGG-, and steel bur–prepared cavities, mean bond strengths (MPa) were 12.76, 8.44, and 6.01, respectively. The bond strength of the TotalFill RRM to dentin was significantly higher in the Er:YAG laser compared with the steel bur–prepared cavities ( p  = 0.004). The bond strength was not significantly different between the Er:YAG and Er,Cr:YSGG cavities ( p  = 0.074) and between the Er,Cr:YSGG and bur cavities ( p  = 0.648). In the cavities prepared by the Er,Cr:YSGG laser and bur, the failure mode of the TotalFill RRM was predominantly mixed, then adhesive and cohesive. In the Er:YAG laser–prepared cavities, the most common failure mode was adhesive, followed by mixed type and no cohesive failure. The bond strength of the TotalFill RRM to dentin was highest in the group of retrograde cavities prepared by the Er:YAG laser.

The aim of this study was to evaluate in vitro the influence of high-power lasers (Nd:YAG and diode 980 nm) associated with mineral coal as fotopotencializer on bond strength of an epoxy resin-based root canal sealer to root dentin, using the pushout test, and on the dentin/filling material interface, using confocal laser microscopy. For this purposes, 50 canines were instrumented with Mtwo rotary system up to #50.04 instrument and randomly assigned to five groups (n = 10): group I—control EDTAC; group II—EDTAC and Nd:YAG laser; group III—EDTAC and diode laser 980 nm; group IV—EDTAC, Nd:YAG laser and mineral coal 5 g/100 mL; and group V—EDTAC, diode laser 980 nm and mineral coal 5 g/100 mL. All data were analyzed by ANOVA (at 5% significance level) following the Kruskal-Wallis, Dunn and Tukey tests. The group I increased more bond strength of the sealer to root dentin that treated with only EDTAC 17% (17.21 ± 21.75 MPa), similar to the group II (12.21 ± 18.20 MPa) and group IV (14.92 ± 28.06 MPa), both treated with Nd:YAG laser, with the exception of group IV, which was added to mineral coal. The group V (8.75 ± 13.42 MPa) had similar results to the groups II and IV, but the same similarity were found when compared with group III (7.11 + 11.28 MPa), with lower results. Regarding the root thirds, the apical third (23.27 ± 29.21 MPa) presented a statistically higher value on bond strength than the cervical third (5.92 ± 5.33 MPa) and middle third (6.93 ± 7, 11 MPa) (p > 0.05). Group II (86.27 μm) showed the highest tags penetration values, with a statistically difference to the group III (51.57 μm), IV (36.77 μm) and V (32.37 μm) (p < 0.05). Group I (71.63 μm) was statistically similar to groups II and III (p > 0.05). Group IV had the lowest values and was statistically similarity to groups III and V (p > 0.05). It was concluded that the treatment with Nd:YAG laser provides better results than the diode 980 nm laser, except when was added mineral coal. The control and diode 980 nm laser groups presented less adhesive failures and more mists failures than the other groups. Both lasers did not interfere negatively compared to the control group.

Skeletal remains are among the most challenging forensic samples, and when extracting DNA from them, destructive grinding is usually employed to obtain a sufficient quantity of DNA. When identifying skeletonized remains, a nondestructive extraction method is of great importance, and undamaged skeletal remains should be returned to relatives after identification due to ethical issues. Teeth are a good source of DNA, which can be found in dental pulp, dentin, and cementum. Similar to bones, highly destructive grinding of the entire tooth is usually employed in the standard forensic extraction procedure. Recent studies have shown that DNA can be best preserved within teeth in the cementum layer of the tooth root. The DNA in the tooth root surface is easily accessible. A simple and fast nondestructive method without grinding, drilling, or scraping of the tooth was developed. A commercial forensic extraction kit was used for automated DNA purification. Sixty-two canines from adult skeletons excavated from two archaeological cemeteries dating from the 13th to 19th centuries were used for analysis. After chemical cleaning and UV irradiation, demineralization was performed by submerging the tooth in 0.5 M EDTA, followed by lysis of demineralized tissue and automated DNA purification. Real-time PCR quantification was employed to determine the quality and quantity of DNA. The efficiency of the nondestructive DNA extraction method developed for genetic analysis of teeth was evaluated by determining the DNA yield, degree of DNA degradation, and success of short tandem repeat (STR) typing. The results showed high efficiency of the method developed, with highly informative STR profiles obtained from 74 % of archaeological canines analyzed. This study highlights the potential of a nondestructive method for analysis of skeletal remains, and it discusses the practical implications of teeth for forensic investigations. The method developed to physically preserve the tooth is simple, fast, and highly efficient, and, because of reduced manual handling, it has a low risk of contamination. •Nondestructive DNA extraction method allows preservation of the specimen.•Canines from 62 adult skeletons from modern-era cemeteries were analyzed.•DNA was extracted employing decalcification and lysis without damaging the tooth.•Highly informative STR profiles were generated from 74 % of canines.

In-vitro-studies usually require extracted teeth, which have been stored over an extended period of time. It can be assumed that storage solutions and time may alter the mechanical properties of dentin. The aim of this study was to examine Martens hardness parameters of bovine dentin with regard to the storage medium and storage time for up to 6 months. Standardized root dentin bars from extracted bovine incisors were stored in thymol 0.1%, chloramine-T 0.5%, formalin 10% and double distilled water. At baseline and after storage periods of 1, 3, and 6 months, samples were analyzed regarding Martens hardness, indentation hardness, indentation modulus, and indentation creep (linear mixed-effects regression models). Within 3 months of storage at the latest, all solutions showed significantly reduced values for Martens and indentation hardness. Regarding the indentation modulus, a reduction was observed for all groups at 6 months at the latest. In general, chloramine-T was shown to have the least impact on the mechanical properties of bovine dentin. Within the limitations of this study, storage medium and time should always be considered when conducting studies on the mechanical properties of bovine dentin, including any unfavorable changes of the dental hard tissues.

Dentin is a vital, hydrated composite tissue with structural components and properties that vary in the different topographic portions of the teeth. These variations have a significant implication for biomechanical teeth properties and for the adhesive systems utilized in conservative dentistry. The aim of this study is to analyse the root canal dentin going from coronal to apical zone to find the ratio between the intertubular dentin area and the surface occupied by dentin tubules varies. Observations were conducted on 30 healthy premolar teeth extracted for orthodontic reasons in patients aged between 10 and 14. A SEM analysis of the data obtained in different canal portions showed that, in the coronal zone, dentinal tubules had a greater diameter (4.32 μm) than the middle zone (3.74 μm) and the apical zone (1.73 μm). The average number of dentinal tubules (in an area of 1 mm2) was similar in coronal zone ( 46,798 ± 10,644 ) and apical zone ( 45,192 ± 10,888 ), while in the middle zone they were lower in number ( 30,940 ± 7,651 ). However, intertubular dentin area was bigger going from apical to coronal portion. The differences between the analysed areas must be considered for the choice of the adhesive system.

Acellular extrinsic fiber cementum is a mineralized tissue that covers the cervical half of the tooth root surface. It contains mainly extrinsic or Sharpey's fibers that run perpendicular to the root surface to anchor the tooth via the periodontal ligament. Acellular cementum is continuously and slowly produced throughout life and exhibits an alternating bright and dark pattern under light microscopy. However, although a better understanding of the structural background of acellular cementum is relevant to many fields, such as cementochronology, periodontology and tissue engineering, acellular cementum remains rarely studied and poorly understood. In this work, we studied the acellular cementum at the incremental line scale of five human mandibular canines using polarized Raman spectroscopy. We provided Raman imaging analysis and polarized acquisitions as a function of the angular orientation of the sample. The results showed that mineral crystals were always parallel to collagen fibrils, and at a larger scale, we proposed an organizational model in which we found radial collagen fibers, \"orthogonal\" to the cementum surface, and \"non-orthogonal\" fibers, which consist of branching and bending radial fibers. Concerning the alternating pattern, we observed that the dark lines corresponded to smaller, more mineralized and probably more organized bands, which is consistent with the zoological assumption that incremental lines are produced during a winter rest period of acellular cementum growth.

Objectives The aim of this study was to evaluate the porosity and assess the root dentine to material interface of four root-end filling materials based on tricalcium silicate cement using two microscopy techniques. Methods The porosity of Bioaggregate, Biodentine, a prototype radiopacified tricalcium silicate cement (TCS-20-Zr) and intermediate restorative material (IRM) was evaluated after immersion for 28 days in Hank's balanced salt solution (HBSS) using mercury intrusion porosimetry. The root dentine to material interface of the cements when used as root-end filling materials in extracted human teeth was assessed after 28 days of dry storage and immersion in HBSS using a confocal microscope together with fluorescent tracers and also a field emission gun scanning electron microscope. Results Biodentine and IRM exhibited the lowest level or degree of porosity. The confocal microscopy used in conjunction to fluorescent tracers demonstrated that dry storage resulted in gaps at the root dentine to material interface and also cracks in the material with Biodentine being the most affected. Zinc was shown to be present in root dentine adjacent to the IRM restorations. Conclusions Dry storage of Biodentine resulted in changes in the material microstructure and cracks at the root dentine to Biodentine interface. Furthermore, the gaps resulting from material shrinkage allowed the passage of the fluorescent microspheres thus indicating that these gaps are significant and can potentially allow the passage of micro-organisms.

The aims of this laboratory study were to compare the effects of lesion baseline severity, mineral distribution and substrate on remineralization and progression of caries lesions created in root dentin. Lesions were formed in dentin specimens prepared from human and bovine dentin using three protocols, each utilizing three demineralization periods to create lesions of different mineral distributions (subsurface, moderate softening, extreme softening) and severity within each lesion type. Lesions were then either remineralized or demineralized further and analyzed using transverse microradiography. At lesion baseline, no differences were found between human and bovine dentin for integrated mineral loss (ΔZ). Differences in mineral distribution between lesion types were apparent. Human dentin lesions were more prone to secondary demineralization (ΔΔZ) than bovine dentin lesions, although there were no differences in ΔL. Likewise, smaller lesions were more susceptible to secondary demineralization than larger ones. Subsurface lesions were more acid-resistant than moderately and extremely softened lesions. After remineralization, differences between human and bovine dentin lesions were not apparent for ΔΔZ although bovine dentin lesions showed greater reduction in lesion depth L. For lesion types, responsiveness to remineralization (ΔΔZ) was in the order extremely softened > moderately softened > subsurface. More demineralized lesions exhibited greater remineralization than shallower ones. In summary, some differences exist between human and bovine dentin and their relative responsiveness to de- and remineralization. These differences, however, were overshadowed by the effects of lesion baseline mineral distribution and severity. Thus, bovine dentin appears to be a suitable substitute for human dentin in mechanistic root caries studies.

Post-mortem DNA degradation is still the real challenge of DNA-based identification in forensic practise. It is a complicated multifactorial process occurring as a result of the combination of several different environmental effects along with the crucial effect of the elapsed post-mortem interval (PMI). The main purpose of the present study is to evaluate the effect of ante- and post-mortem factors on dental DNA in real forensic cases. Ninety-five teeth extracted from 39 corpses, whose bodies were subject to 6 different post-mortem conditions, were used to evaluate dental DNA amount. In total, 179 DNA extracts isolated from the root of the teeth were examined after removing the crown and sectioning each root into apical and cervical portions. DNA concentration was measured using real-time polymerase chain reaction DNA quantitation kit (PowerQuant™ System/Promega). Our results indicate that the post-mortem interval (PMI) is the most important influential factor on dental DNA quantification (p < 0.001). However, in the actual data set, it was confounded with several ante- and post-mortem factors, rendering its actual net effect difficult. The time period of the first 10 days after death yielded the best DNA results from all analysed dental samples. Afterwards, a dramatic decrease in dental DNA was observed in the following time period. Teeth extracted from burnt and fresh corpses yielded the highest amount of DNA, while skeletonized exhumed corpses resulted in the lowest DNA amount. Indeed, dry and indoor conditions demonstrated better results than those in water, outdoors, or buried in the ground. On the other hand, ante-mortem factors including sex, age, tooth type, and tooth root portions did not reveal significant effect on dental DNA yield. We suggest that ante-mortem factors are considerably more subjected to individual variations. Post-mortem factors including PMI, post-mortem conditions, and the relevant surrounding environments have substantial influence on the dental DNA amount yielded.

The aim of this study was to evaluate the chemical stability of endodontic-treated root dentin after different laser irradiations through Raman spectroscopy. Fifty maxillary canines were selected and prepared with K3 system. Roots were randomly distributed into five groups ( n  = 10) according to the surface treatment: GI (water), GII (NaOCl + EDTA), GIII (NaOCl + EDTA + 980 nm Diode laser), GIV (NaOCl + EDTA+ 1064 nm Nd: YAG laser) and GV (NaOCl + EDTA+ 2780 nm Er,Cr: YSGG laser). Lasers were applied for 20 s. Samples were bisected, and the organic and inorganic content of dentin was analyzed by Raman spectroscopy. Data were submitted to ANOVA and Tukey tests ( p  < 0.05). None of the surface treatments alter the inorganic content (cts) ( p  = 0.183). Roots irradiated with Er,Cr: YSGG laser had a reduced collagen content (GV-290.7 ± 41.7) compared with the water-treated roots (GI-328.3 ± 63.5) and those treated with NaOCl + EDTA (GII-333.9 ± 55.8). Roots irradiated with Er,Cr: YSGG laser also showed a higher inorganic/organic ratio (GV-9.5 ± 1.1) than roots treated with water (GI-7.7 ± 1.5), NaOCl + EDTA (GII-8.0 ± 1.4) and diode laser (GIII-8.2 ± 1.6). Both organic and inorganic contents increased from cervical to apical thirds in all groups. None of the surface treatments were able to promote changes in the inorganic content of the root dentin; treatment with NaOCl + EDTA combined with Er,Cr: YSGG altered collagen.