Human Canines Research Articles

Color Masking Ability of Guided Enamel Regeneration with a Novel Self-Assembling Peptide and Resin Infiltration on Artificial Enamel Lesions Under Various Challenges: An In Vitro Spectrophotometric Analysis

The color masking ability of resin infiltration (RI) and curodont repair fluoride plus–self-assembling peptide (CRFP-SAP) was investigated under various simulated oral challenging conditions. Sixty-four extracted caries-free human canines were randomly divided into two groups: Group 1 (RI) and Group 2 (CRFP-SAP). The baseline color values of samples were recorded using a spectrophotometer (VITA Easyshade® Advance 4.0 VITA Zahnfabrik, Bad Sackingen, Germany). The samples were stored in a demineralization solution for 4 days to induce artificial enamel lesions (AELs). The AELs of Groups I and II were treated with RI (Icon, DMG, Hamburg, Germany) and CRFP-SAP (vVARDIS, Zug, Switzerland), respectively, followed by color measurements. Each group was subjected to challenges such as remineralization, pH cycling, staining, and thermocycling, followed by color measurements. The difference between the mean ∆E (color difference value) of sound enamel and both treatment groups was less than 3.7 1-week post treatment. Meanwhile, the difference between the mean ∆E of RI-treated samples and all kinds of challenges was more than 3.7, while for the CRFP-SAP-treated samples, it was less than 3.7 for all kinds of challenges, except for the thermocycling, for which the mean ∆E difference was 4.3. RI and CRFP-SAP treatments were effective in masking the discoloration caused by AELs. However, the color was not stable for RI-treated samples, whereas it was stable for CRFP-SAP-treated samples under all challenges, except for thermocycling.

Evaluation of effects of different sizes and shapes of attachments during rotation, tipping, and torquing in clear aligner therapy - A finite element study.

To evaluate the effect of different shapes and sizes of attachments used for rotation, tipping, and torquing tooth movement in clear aligner therapy. Using computer-aided design/computer-aided manufacturing technology, 15 replicas of the upper right human canines were produced. Finite element analysis (FEA) was utilized to mimic tooth movement by applying a constant force of 2.942 N to these models, which contained various forms and sizes of composite attachments. Analysis was done on the stress on different dental structures and the displacement of the attachments. The outcomes demonstrated that tooth movement during clear aligner treatment was considerably impacted by attachment size and shape. Rectangular beveled attachments with dimensions of 3.5 mm × 1.2 mm × 3.5 mm showed the greatest rotating mobility. Triangular beveled attachments with dimensions of 5 mm by 0.8 mm by 2 mm produced the most displacement during tipping motion. For torquing motions, rectangular power ridge attachments with dimensions of 0.5 mm × 0.5 mm × 5 mm worked well. The size and geometry of composite attachments were shown to be extremely important in regulating tooth movement during clear aligner treatment, according to this FEA research. Greater displacement is produced when smaller attachments with less surface area dissipate more force. When using clear aligner therapy, orthodontists may optimize treatment plans, shorten treatment times, and provide more predictable results by having a better understanding of the biomechanics of various attachment designs.

Can Heated Distilled Water Effectively Prevent Precipitate Formation between NaOCl and CHX?

The present study aimed to investigate the capacity of different irrigation protocols using heated distilled water at 65°C (HDW), in preventing the formation of the brown-orange precipitate observed after the interaction between sodium hypochlorite (NaOCl) and chlorhexidine (CHX). Forty human canines were selected, prepared, and cleaved in two halves. Images of delimited areas in each root canal thirds were obtained through a stereomicroscope (16x and 40x). After reassembly, the teeth were distributed into four groups (n = 10) according to the final irrigation protocol: G1 (no HDW): EDTA + NaOCl + CHX with conventional irrigation (CI); G2 (HDW + CI): EDTA with passive ultrasonic irrigation (PUI) + NaOCl (PUI) + HDW (CI) + CHX (PUI); G3 (HDW + PUI): EDTA + NaOCl + HDW + CHX with PUI; G4 (HDW + CUI): EDTA (PUI) + NaOCl (PUI) + HDW with continuous ultrasonic irrigation (CUI) + CHX (PUI). After irrigation, the teeth were re-separated and images of the same delimited areas were obtained again. Scores were assigned according to the amount of precipitate observed, comparing the initial and final images. The data were submitted to Kruskal-Wallis, Dunn and Friedman statistical tests (α = 5%). G1(no HDW) showed the highest scores in the analysis between groups (p < 0.001), with a greater amount of precipitate in the cervical and medium thirds (p < 0.001). The thirds of the other experimental groups did not differ from each other (p > 0.05). The intermediate irrigation with heated distilled water at 65°C prevented the formation of brown-orange precipitate, regardless of the use of ultrasonic activation (PUI or CUI).

Evaluation of Er:YAG and Er,Cr:YSGG lasers on intraradicular bonding using modified glass fiber tips.

The aim of this study was to determine whether erbium laser irradiation emitted by modified glass-fiber tips would improve the intraradicular bonding of fiber posts. Forty human canines were endodontically treated and prepared for fiber-post placement. Roots were divided into five groups (n=8); according to the laser-tip combinations (2,940 nm Er:YAG and 2,780 nm Er,Cr:YSGG). Non-irradiated root canals served as control. Posts were cemented with self-adhesive resin cement and subjected to push-out test. Failure modes were characterized, and intraradicular bonded interfaces were analyzed by SEM and submitted to nanoleakage evaluation. Data were analyzed by two-way ANOVA and Tukey test (α=0.05). No significant differences were observed in cervical and middle sections (p>0.05), while significantly higher bond strengths were observed in apical sections (p<0.05). Laser irradiation reduced adhesive failures, cement-dentin gap formation, and nanoleakage apically. Laser-irradiation protocols employing end- or radial-firing tips improved bonding to apical intraradicular dentin contributing to more uniform bonded interfaces.

Effect of Whitening Toothpastes with Different Active Agents on the Abrasive Wear of Dentin Following Tooth Brushing Simulation.

The aim of this research was to evaluate the abrasive dentin wear that can be induced by three commercial whitening toothpastes following a tooth-brushing simulation (TBS) corresponding to a three-month period. Sixty human canines were selected, and the roots were separated from the crowns. Then the roots were randomly divided into six groups (n = 10) and were submitted to TBS using the following slurries: Group 1-deionized water (RDA = 5); Group 2-ISO dentifrice slurry (RDA = 100); Group 3-a regular toothpaste (RDA = 70); Group 4-a charcoal-containing whitening toothpaste; Group 5-a whitening toothpaste containing blue covasorb and hydrated silica; and Group 6-a whitening toothpaste containing microsilica. Following TBS, surface loss and surface roughness changes were evaluated using confocal microscopy. Additionally, surface morphology and mineral content changes were observed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The deionized water group presented the lowest surface loss (p < 0.05), while the charcoal-containing toothpaste presented the highest surface loss, followed by ISO dentifrice slurry (p < 0.001). Blue-covasorb-containing and regular toothpastes did not present statistically significant differences (p = 0.245), and neither didmicrosilica-containing toothpaste or ISO dentifrice slurry (p = 0.112). The surface height parameters and surface morphology changes of the experimental groups followed the surface loss patterns, while no differences were detected in mineral content after TBS.Although the charcoal-containing toothpaste exhibited the highest abrasive wear to dentin, according to ISO 11609, all the tested toothpastes exhibited appropriate abrasive behavior towards dentin.

The terrestrial malacofauna of Eastern Algeria during the Upper Capsian: The case of Medjez I (El Eulma)

The rammadiya of Medjez I, located near El Eulma (eastern Algeria), is one of the best known sites of the Upper Capsian. The discovered terrestrial malacofauna comes from two excavations (2013 and 2017). The majority of the shells belong to two species: Helix melanostoma and Xerosecta sp. (more than 90% of the total malacofauna). The high proportion of young individuals of Xerosecta sp., the small size of its shell and the presence of faunal remains highlight the negligible - secondary or complementary - role of the terrestrial malacofauna in the diet of the occupants of Medjez I. The molluscs could be cooked on heated stones, a technique that will preserve the structure of the shell. The presence of systematic (or regular) anthropogenic perforations is due, for a large part, to the methods of extraction of the animal from its shell for consumption: piercing by human canines and/or by a flint or bone tool. However, certain types of perforation, located just behind the peristome at the level of the last whorl of the shell, could have had the objective of manufacturing collars or other ornamental objects. The collection season for the land snail species identified in the site could have taken place during several periods of the year depending on the adaptation of each species to climate change.

Impact of radiotherapy on the morphological and compositional structure of intra-radicular dentin

Considering the side effects in the oral cavity and dental structures of radiotherapy (RDT) for head and neck cancer, this study aimed to evaluate the effects of RDT on the root dentin concerning the obliteration of dentinal tubules, the inorganic composition of intra-radicular dentin, and the integrity of collagen fibers. Thirty human canines were selected from a biobank and randomly divided into two groups (n=15). The samples were sectioned buccolingually, and a hemisection was used for structural analysis by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS). Low-vacuum SEM images were obtained at 2000-x magnification to observe the obliteration of the dentinal tubules. Moreover, compositional evaluation was performed using EDS. After RDT, the SEM and EDS analyses were repeated using the same methodology. RDT was applied fractionally at 2 Gy per day, 5 days per week, for 7 weeks, resulting in a total dose of 70 Gy. The collagen integrity of the irradiated and non-irradiated samples was analyzed using Masson's trichrome and picrosirius red staining polarization microscopy. Samples subjected to RDT exhibited dentinal tubule obliteration (p < 0.001); low integrity of type I and III collagen fibers (p < 0.05); compositional reduction of calcium (p = 0.012), phosphorus (p = 0.001), and magnesium (p < 0.001); an increased Ca/P ratio (p < 0.001). RDT affects the structure of dentinal tubules, the inorganic composition of intra-radicular dentin, and the collagen fiber integrity in the root dentin, which may interfere with the effectiveness and durability of dental procedures.

The current consumption of land snails in Tunisia: An ethnographic study

Piercing of land snails is archaeologically attested in prehistoric North Africa, but there is very little information about the techniques employed by the ancient peoples. This ethnographic study aims to throw light on this phenomenon. The consumption of land snails is one of the important culinary traditions of a large part of the current Tunisian population. Collected terrestrial gastropods and their preparation vary from one region to another and from one family to another. Consumption techniques depend on the position of the body of the mollusc at the entrance of the shell after cooking and the consumer's mastery of extraction techniques. In addition to simple extraction, the piercing of the shells, by human canines or by any other tool, offers an effective solution for removal of the animal from the shell. The position of the perforation on the shell (upper or lower part) is related to the part of the mollusc flesh desired by the consumer.

Glass Fiber Post lengths and adhesive strategies to restore extensively damaged canines

The aim of this study was to evaluate different post lengths and adhesive strategies for restoring extensively damaged canines. Sixty human canines were randomly distributed into two groups (n=30), according to the resin cement used: self-adhesive or conventional. Each group was further distributed into 3 groups (n=10) based on the intracanal post lengths: 5, 7.5 and 10 mm. The radicular portion was endodontically filled, the cervical third was enlarged to simulate extensive damage and the coronal portion was reconstructed with composite resin. The samples were prepared with a simulated periodontal ligament and submitted to fatigue loading (160N – 1,200,000 cycles), followed by fracture resistance testing. The results were submitted to two-way ANOVA and Tukey tests (α=5%). The assessed glass fiber post lengths have not influenced on the fracture resistance (p&gt;0.05). However, the performance of the conventional cements was better than the self-adhesive cements when the same post length was compared (p&lt;0.05). Repairable fractures were prevalent (70-90%) in all groups tested. Conventional resin cement yielded higher fracture resistance than self-adhesive cement, regardless the post length adopted.

Effect of Different Ceramic Materials on Fatigue Resistance and Stress Distribution in Upper Canines with Palatal Veneers.

The aim of this study was to evaluate, by means of a fatigue life test, different ceramic materials used in palatal veneers to restore the canine guidance. Forty-five standardized anatomical preparations were made in extracted healthy human canines with 1.2 uniform thickness. Samples were scanned, restorations were designed and milled in polymer-infiltrated ceramic network (PICN, Vita Enamic), zirconia-reinforced lithium silicate (ZLS, Vita Suprinity), and high translucent yttrium oxide-stabilized tetragonal zirconia (YZHT, Vita YZHT). Dental preparations were etched, restorations were processed according to the manufacturers' recommendations, and adhesively cemented. Then, three samples of each group were tested with load-to-fracture to determine the fatigue parameters. In addition, the palatal veneers stresses were evaluated using numerical models through finite element analysis. The mean of the monotonic test for PICN, ZLS, and YZHT was 674.18 N, 560.5 N, and 918.98 N, respectively. The StepWise test was performed until specimen fracture or until suspension of the test after 1.2 × 106 cycles. Regarding survival, using the Kaplan-Meier method, PICN presented results for the mean and median of 245.21 N and 225 N, respectively; ZLS had an average of 175.76 N and a median of 168 N, and YZHT with an average of 383.30 N and a median of 366 N. Regarding the Weibull method, PICN showed results of 5.43 β and 264 η for form and scale, respectively; ZLS had 36.14 β for form and 380.67 η for scale; and YZHT presented 4.95 β for form and 417.38 η for scale. The highest stress value was calculated for YZHT, ZLS, and PICN, respectively. It was possible to conclude that all tested materials have the possibility of being used for rehabilitation of upper canines' palatal surface.

Evaluation of microleakage of three different endodontic sealers in the presence and absence of moisture

Background and aims: AH26, Master-Dent, and Endoseal mineral trioxide aggregate (MTA) are three different types of sealers. The purpose of this study was to assess and compare THE apical seal of the root canal-treated teeth with the above-mentioned sealers in the presence and absence of moisture using the fluid filtration method. Methods: To this end, 54 freshly extracted single root canal human canines were selected for this study. The canals were prepared using rotary instruments, and then sodium hypochlorite was applied as an irrigation solution in this protocol. The specimens were randomly divided into three groups of 18. One group was obturated with the gutta-percha by the cold lateral compaction technique. Half of one of the aforementioned sealers belonged to the group of moistened teeth and the other half to the group of the dried teeth. Microleakage in all groups was assessed 3 months after the obturation of canals by the fluid filtration method. The data were analyzed using ANOVA and Tukey’s post hoc tests, and the level of significance was set at P&lt;0.05. Results: The results showed that the minimum and maximum micro-leakage belonged to Masterdent dry (mean leakage = 1.7778 μL/ min/CmH20) and Endoseal-MTA dry (mean leakage = 3.5000 μL/min/CmH20), respectively. All three groups of sealers exhibited a significant difference in apical micro-leakage between dry and moist conditions (PMasterdent &lt;0.001, PAH26=0.002, and PEndoseaL-MTA =0.007). Conclusion: The findings of this experimental study demonstrated that Masterdent provided the least apical micro-leakage under dry conditions while Endoseal-MTA had the highest micro-leakage under these conditions. There was a significant difference between dry and moist conditions in all groups.

Eliminación de la capa de barro dentinario mediante irrigación ultrasónica pasiva y continua: un estudio de microscopía electrónica de barrido

Background: Due to the anatomical complexity of the root canal system, irrigation plays an essential role in endodontics. This in vitro study was sought to compare the removal of the smear layer (RSL) promoted by conventional irrigation (CI), passive ultrasonic irrigation (PUI) and continuous ultrasonic irrigation (CUI) with 17% EDTA, by using scanning electron microscopy (SEM). Material and Methods: Forty single-rooted human mandibular canines were instrumented and randomly assigned to four groups (n=10), according to the irrigation protocol aiming to the RSL: CG (control group) —conventional irrigation with distilled water; CI— conventional irrigation with 17% EDTA; PUI —passive ultrasonic irrigation with 17% EDTA; CUI— continuous ultrasonic irrigation with 17% EDTA. Hemisections from each sample were obtained, and images of each root canal third (cervical, middle and apical) were captured at 1000 X magnification by SEM. Three previously calibrated and blinded evaluators classified the RSL, according to the criteria proposed by Torabinejad et al.: small or no smear layer (all dentinal tubules were clean and open); 2 = moderate smear layer (no smear layer on the surface of root canal, but dentinal tubules contained debris); 3 = dense smear layer (covering practically all dentinal tubules entrances). Statistical analysis was performed by Kruskal-Wallis and Bonferroni tests (p&lt;0.05). Results: Overall, CUI and cervical thirds showed better RSL rates, compared with the other methods and thirds, respectively (p&lt;0.05). More specifically, the cervical thirds showed better results in the CG, CI and PUI groups (p&lt;0.05), whereas the cervical and middle thirds were not significantly different in the CUI group. Conclusion: CUI was the most effective method for the RSL.

Conventional microscopy makes perikymata count and spacing data feasible for large samples.

Current methods of quantifying defects of dental enamel (DDE) include either gross or low-level examination for linear enamel hypoplasia, histological analysis of striae of Retzius, or scanning electron microscopy (SEM) of a tooth or a tooth cast. Gross examination has been shown to miss many defects. Other methods can be destructive, require transporting samples, and are expensive. Here, we show that digital light microscopy (DLM) can be used for the analysis of DDE as indicated by widened perikymata spacing (WPS). This method takes advantage of high-power (100×) microscopy, but is non-destructive, can be implemented almost anywhere, and is inexpensive. As proof of concept, we created photomontages of labial surfaces of five human canines from images made using DLM and SEM. We counted and measured the widths of all visible perikymata for each imaging modality and fit measurements to a negative curve representing the expected values for each tooth. We calculated residuals for each measurement. WPS were defined when R2 was in the 90th percentile, and were considered matched in DLM and SEM images when observed within the same decile of the tooth surface. There were more WPS detected in the images derived from DLM than from SEM. Overall, the data derived from the two imaging modalities provided similar information about the frequency and timing of stress during dental development. The method described here allows for DDE data acquisition as WPS from large samples, making feasible population-level studies that reflect sophisticated understanding of dental development.

CAD/CAM Milled Glass Fiber Posts: Adaptation and Mechanical Behavior in Flared Root Canals

This study aimed to evaluate the cementation and mechanical behavior of flared root canals restored with CAD/CAM milled glass fiber post-and-core systems. Sixty-six endodontically treated human canines with a flared root canal were divided into three different groups according to the type of post: GPF received prefabricated posts; GREL received relined glass fiber posts, and GMILLED received CAD/CAM milled glass fiber posts. Cementation was performed with self-adhesive resin cement. The samples were submitted to x-ray microcomputed tomography analysis for the analysis of voids and gaps. The roots were sectioned and submitted to the push-out bond strength test. The load-to-fracture was evaluated in post-and-core systems. GMILLED presented lower void and lower gap volumes when compared to GPF and GREL. On the load-to-fracture test, GREL presented statistically significant higher values than GMILLED. GPF values had no statistically significant difference from the two other groups. On the push-out bond strength test, GPF presented statistically significant lower values when compared to GREL and GMILLED. The most common failure pattern was between dentin and cement in all groups. CAD/CAM milled glass fiber post-and-core systems presented an enhanced adaptation of glass fiber posts to flared root canal systems. Their results were comparable to relined posts in bond strength, while load-to-fracture-results for GMILLED were lower than those for GPF.

Evaluation of various methods of methylene blue removal from the post space after photodynamic therapy on the bonding interface using different resin cementation systems.

To evaluate the effects of three protocols for removing 0.01 % methylene blue from the post space after photodynamic therapy on bond strength and tag formation in the dentin of the fiber post space, using a conventional cementation system with an etch-and-rinse or universal adhesive system. Sixty human canines were endodontically treated for fiber post cementation. The specimens were randomized into 6 groups (n = 10): G1, G2, G3, G4, G5, and G6. The G1, G2, and G3 groups were irrigated with saline solution, 2.5 % sodium hypochlorite (NaOCl), and 2.5 % NaOCl, agitated by passive ultrasonic irrigation (PUI), respectively. In these groups, a conventional cementation system with etch-and-rinse adhesive was used. The G4, G5, and G6 groups were irrigated with the respective solutions mentioned above and cemented using a conventional cementation system with universal adhesive. Tag formation in the dentin was evaluated by confocal laser scanning microscopy. The push-out bond strength test was performed on three thirds of the specimens. In the cervical and middle thirds, the greatest extent of dentin tag formation occurred in the G1 (p = 0.023 and p = 0.033, respectively). In the apical third, G1, G2, and G3 demonstrated similar tag formation between themselves (p = 0.089). In the cervical and middle thirds, G4 demonstrated the highest bond strength when compared to the other groups (p < 0.05). The protocols for removing 0.01 % methylene blue with NaOCl, irrespective of the involvement of passive ultrasonic irrigation, negatively effects the bond strength and tag formation in the dentin of the post space.

The influence of working length on the reduction of biofilm and planktonic bacteria in oval canals with reciprocating instrumentation

To evaluate the influence of reciprocating single-file instrumentation with different working lengths (WL) on the reduction of planktonic bacteria and bacterial biofilm in Enterococcus faecalis-contaminated oval root canals. Methodology: Fifty-five human single-rooted canines were used. Fifty were inoculated with E. faecalis for 21 days for biofilm formation. To confirm the formation of biofilm adhered to the root canal wall, 5 contaminated samples from positive control group were analyzed by SEM. Samples were assigned into 3 groups (n = 15) according to working length determined, G+1 root canal preparation 1 mm beyond the apical foramen, G0 root canal preparation at the major foramen, and G-1 root canal preparation 1 mm short of the major foramen. Five roots were not inoculated to serve as a negative control. Bacteriological samples were collected prior to preparation, initial collection (S1), and after reciprocating instrumentation (S2) by disaggregating biofilm to quantify the reduction of planktonic bacteria and intracanal biofilm at different WL. Bacterial quantitation was performed using colony-forming units per milliliter (CFU / mL) count. Statistical analysis was performed at the significance level of 0.05. Results: No bacterial growth was observed in the negative control. All positive controls demonstrated bacterial growth; S1 from all teeth were positive for bacteria with no significant difference. The post-hoc analysis showed G+1 promoting a significantly higher disinfection than G-1 (p&lt;0,05) and G-1 similar disinfection to G0 (P=962). Conclusion: Instrumentation as close as possible to major foramen or beyond it improves decontamination in oval root canals with reciprocating instrumentation.

Spectrophotometric evaluation of the effectiveness of Er,Cr:YSGG laser-assisted intracoronal tooth bleaching treatment using different power settings

BackgroundNon-vital tooth discoloration is a common condition in dental practice. The aim of this in vitro study was to evaluate the efficacy of intracoronal bleaching treatments of non-vital teeth either activated or not by Er,Cr:YSGG laser (2780 nm) operating at 1.25 or 2.5 W. MethodsTwenty four human canines were artificially stained after implementation of root canal treatment. Subsequently, the teeth were randomly divided into three groups (n = 8): Group 1 (control) received intracoronal bleaching treatment with a bleaching gel containing 35 % hydrogen peroxide for 40 min, Group 2 received the same treatment assisted with Er,Cr:YSGG laser (2780 nm) operating at 1.25 W average power for 30 s and Group 3 received the same treatment with Group 2, but the average power was adjusted to 2.5 W. The bleaching treatments repeated after one week. Spectrophotometric analysis of tooth color change (ΔE) was implemented 7 days after both bleaching sessions. ResultsThe results of two-way ANOVA revealed that there was a tendency of no significant difference in color change between the three experimental groups (p = 0.063). However, the between-group comparisons showed that laser 2.5 W group had significantly higher ΔE than the control group after the first bleaching session. Moreover, a significant interaction between bleaching treatment and number of applications was detected (p = 0.026). ConclusionsEr,Cr:YSGG laser irradiation significantly increased ΔE only after the first bleaching session when operating at 2.5 W. After the second bleaching session ΔE was not different compared to the control group, irrespectively of the laser power settings.

Sexual dimorphism applying the mandibular canine index in a Brazilian sample: a pilot study

The aim of this study was to apply the morphometric quantification of the canine index for sexual dimorphism in a Brazilian sample. The sample consisted of 90 participants (45 males and 45 females) aged between 18 and 35 years. With the aid of a digital caliper, the intraoral mesio-distal measurement of the permanent mandibular right canine (MD43) and the intercanine distance (IC) were taken by three examiners. The measurements were used in a formula established by Rao, Rao, Pai e Kotian (1989) to estimate sex based on morphometric features of the human canines. The applicability of this approach for sexual dimorphism was assessed based on the inherent mandibular canine index (MCI) calculated by the formula. The MCI was higher in males than females. The mean general accuracy rate of the MCI for sexual dimorphism in the total sample was 52.22%. In males, the MCI was able to properly distinguish sex in 82.22% of the sample, while in females the accuracy decreased to 22.22%. These outcomes raise the attention for the careful use of the MCI in practice – especially in the field of Forensic Anthropology. In particular, the accuracy of the method was close to random in a sample that contained both sexes. Thus, MCI should not be used as the only tool for sexual dimorphism.

Removal of filling material using rotating or reciprocating systems with or without solvent: microCT analysis.

This study evaluated by the efficacy of rotary and reciprocating systems to remove filling material by micro-CT. Sixty human canines were instrumented up to F3 by ProTaper Universal system and filled with AH Plus/ gutta-percha. Specimens were submitted to 1,200 thermal cycles, scanned by microCT SkyScan 1176 and randomly distributed in groups according to the filling material removal protocol (n = 10): ProTaper Universal, ProTaper Universal/xylol, ProTaper Next, ProTaper Next/xylol, Reciproc and Reciproc/xylol. After filling removal, specimens were analyzed by microCT to separately verify the presence of gutta-percha and sealer remnants. The data (mm3) were analyzed by two way ANOVA and Tukey´s test (5%). For the remaining gutta-percha, the use of xylol provided the highest values for Reciproc (7.60 ± 0.73), which was statistically different from the other groups (p < 0.05) that presented lower values and were statistically similar to each other (p > 0.05). For the remaining sealer, xylol provided the highest values (21.25 ± 6.94) different (p < 0.05) from the use of instruments alone (11.47 ± 9.45). ProTaper Next presented the lowest values (8.16 ± 1.37) for the remaining sealer, different (p < 0.05) from that of Reciproc (24.67 ± 6.32). The qualitative analysis revealed that all groups presented some remaining root filling material, with the highest volumes presented by Reciproc and Reciproc/xylol. In conclusion the rotary systems provided greater removal of filling material regardless of the use of xylol. The use of xylol negatively interfered with the action of the reciprocating system in the removal of the gutta-percha and sealer.

Resistance to fracture of intraradicular posts made of biological materials

BackgroundThe aim was to analyze the fracture resistance of human teeth treated endodontically and restored with posts made of bovine dentin, human dentin, or glass fiber, and to evaluate the fracture pattern.MethodsCylindrical posts of 1.5 mm in diameter cemented to the roots of human maxillary canines presented a length of 15 mm, cervical diameter of 5–5.5 mm in the mesiodistal direction, and 7–7.5 mm in the vestibule-palatal direction. The groups studied were: Group I—10 glass fiber posts; Group II—10 human dentin posts; Group III—10 bovine dentin posts (self-adhesive resin cement); and Group IV—10 bovine dentin posts (resin-modified glass-ionomer cements). The coronal part of tooth was restored with a standardized core build-up using composite. All of the groups were submitted to a compression force test and the resistance to fracture was verified using a universal testing machine. The fracture pattern was likewise evaluated.ResultsThe values of resistance to fracture were: 723.3N in group I, 561.5N in group II, 556.6N in group III, and, 613.27N in group IV. However, no statistically significant difference was observed among the groups. The fractures in groups I and II were most commonly found in the middle/apical third and were considered irreparable. For restored teeth in group III, half of the fractures appeared in the cervical third and were reparable. In group IV, all of the fractures were reparable, with the majority in the cervical thirds.ConclusionBovine dentin can be used as intraradicular post to substitute human dentin and glass fiber posts. The greater the malleability of the post, the greater the chances of survival of the teeth when subjected to fracture testing.