Influence of different laser-assisted retrograde cavity preparation techniques on bond strength of bioceramic-based material to root dentine.

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.

Factors affecting dental DNA in various real post-mortem conditions.

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.

Circumferential root strains generated during lateral compaction with stainless steel vs. nickel-titanium finger spreaders.

The circumferential strains created in the radicular dentin by nickel-titanium (NiTi) and stainless steel (SS) finger spreaders (FSs) during a simulated clinical procedure of lateral compaction were compared after minimal (size 50) and extensive (size 100) canal preparations. Nineteen maxillary central incisors underwent minimal preparation, while 10 underwent an extra phase of extensive preparation. Four miniature strain gauges were bonded circumferentially in the apical third of the root (buccal, lingual, mesial, and distal). Lateral compaction was performed using either NiTi-FSs or SS-FSs. Force and strains were continuously recorded. The maximal strains (with and without normalization according to force) were recorded. The SS-FSs generated higher maximal strains normalized according to force compared with the NiTi-FSs. The maximal normalized strains were higher by 37%-43% for the mesial and distal aspects and by 6%-14% for the buccal and lingual aspects after the minimal preparation and by 24%-28% for the mesial and distal aspects and by 19%-20% for the buccal and lingual aspects after extensive preparation. The maximal normalized strains increased by 30%-70% from minimal to extensive preparations, with two teeth exhibiting vertical root fracture while compaction with SS-FS. The NiTi-FSs induce less strain in root dentin than the SS-FSs and thus may contribute less to the risk of vertical root fracture.

Micro-computed tomography assessment of root dentin around fluoride-releasing restorations after demineralization/remineralization.

Using micro-computed tomography (micro-CT), this study assessed the inhibitory effect of three different types of restorations on root-caries formation under a cariogenic challenge. Bovine-root dentin blocks with a cylindrical cavity were divided into three restoration groups: a fluoride-free self-etch adhesive and a resin composite (SE-ES); a self-etch adhesive and a resin composite with multi-ion release (FL-BF); and a glass ionomer cement (Fuji-VII). After the restorative procedures, the specimens were stored in artificial saliva for 1 d, then subjected to a demineralization solution for 4 d and a remineralization solution for 28 d. Mineral density and mean mineral loss of dentin around the restorations were measured using micro-CT. The mean mineral loss values of dentin around the restorations were highest among SE-ES restorations and lowest among Fuji-VII restorations. Fuji-VII showed the highest mineral density and the lowest mineral loss after 28 d of remineralization. The observations made by scanning electron microscopy demonstrated that Fuji-VII created the smallest outer lesion followed by FL-BF and SE-ES. Fuji-VII has a larger inhibitory effect on root caries around the restorations and enhances remineralization more effectively than either FL-BF or SE-ES. Multi-ion and fluoride release from the restorative materials may be beneficial for inhibition of root-dentin caries around the restorations.

In vitro bond strength of an epoxy resin-based root canal sealer to root dentin irradiated with high-power lasers and adhesive interface analyses.

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.

Surface roughness and bacterial adhesion on root dentin treated with diode laser and conventional desensitizing agents.

The treatments for dentin hypersensitivity (DH) may change the surface roughness of the root dentin, which can lead to biofilm accumulation, increasing the risk of root caries. The aim was to compare the surface roughness of root dentin after different treatments of DH and the biofilm formation on those surfaces. After initial surface roughness (Sa) assessment, 50 bovine root fragments received the following treatments (n = 10): G 1-no treatment; G2-5% sodium fluoride varnish; G3-professional application of a desensitizing dentifrice; G4-toothbrushing with a desensitizing dentifrice; and G5-diode laser application (908 nm; 1.5 W, 20 s). The Sa was reevaluated after treatments. Afterward, all samples were incubated in a suspension of Streptococcus mutans at 37 °C for 24 h. The colony-forming units (CFU) were counted using a stereoscope, and the results were expressed in CFU/mL. The one-way ANOVA and the Tukey's tests compared the roughness data and the results obtained on the bacterial adhesion test (α = 5%). G2 (2.3 ± 1.67%) showed similar Sa variation than G1 (0.25 ± 0.41%) and G5 (5.69 ± 0.99%), but different from group G3 (9.05 ± 2.39%). Group 4 showed the highest Sa variation (30.02 ± 3.83%; p < 0.05). Bacterial adhesion was higher in G4 (2208 ± 211.9), suggesting that bacterial growth is greater on rougher surfaces. The diode laser and the conventional treatments for DH may change the surface roughness of the root dentin, but only brushing with desensitizing dentifrice induced a higher bacteria accumulation on root dentin surface.

Variation on Molecular Structure, Crystallinity, and Optical Properties of Dentin Due to Nd:YAG Laser and Fluoride Aimed at Tooth Erosion Prevention.

This in vitro study evaluated the compositional, crystalline, and morphological effects promoted by Nd:YAG laser on root dentin, and verified the effects of laser and topical acidulated phosphate fluoride application (APF-gel) on dentin erosion. 180 bovine dentin slabs were randomized into 4 groups (n = 45): G1-untreated, G2-APF-gel (1.23% F-, 4 min), G3-Nd:YAG (1064 nm, 84.9 J/cm², 10 Hz), and G4-APF-gel application followed by Nd:YAG laser irradiation. The compositional, crystalline, and morphological effects promoted by treatments were investigated on five samples of each experimental group. The other samples were submitted to a 5-day, 10-day, or 15-day erosive and abrasive demineralization and remineralization cycling in order to create erosion lesions. The area and depth of lesions, as well as the optical attenuation coefficient, were assessed, and all data were statistically analysed (p < 0.05). Nd:YAG laser promoted the reduction of carbonate, the formation of tetracalcium phosphate, as well as the melting and recrystallization of the dentin surface. Laser significantly decreased the area and depth of erosion lesions and altered the optical attenuation coefficient when compared to untreated and APF-gel groups, but the association of APF-gel and laser did not promote an additional effect. Nd:YAG laser irradiation can be a promissory treatment to prevent dentin erosion and the abrasion process.

Aspartic acid racemization of root dentin used for dental age estimation in a Polish population sample.

Precise age determination of unidentified bodies and human remains is one of the essential tasks of forensic science. The aim of this study was to assess the applicability of using the enantiomeric composition of aspartic acid racemization in root and crown dentin for dental age estimation using a Polish population sample. Coronal and root dentin from four teeth groups from the mandible were studied using gas chromatography with mass spectrometry. The results demonstrated a very high correlation between the chronological age and enantiomeric composition in both of the dentin samples. Individual linear equations of root dentin with correlation coefficients between 0.96 and 0.98 and a standard estimation error of ±2.95-4.84 years validated the application of aspartic acid racemization as a significant practical contribution to everyday forensic medical practice. Discrepancies in methodological aspects and modifications that simplify the protocol are presented.

Use of XRD and SEM/EDX to predict age and sex from fire-affected dental remains.

In fire scenarios, the application and accuracy of traditional odontological methods are often limited. Crystalline studies and elemental profiling have been evaluated for their applicability in determining biological profiles (age and sex) from human dentition, particularly fire- and heat-affected dental remains. Thirty-seven teeth were paired according to tooth type and donor age/sex for the analysis of crown and root surfaces pre- and post-incineration using X-ray diffraction (XRD) and scanning electron microscopy (SEM/EDX). In unburned crowns, carbon (C) content showed a positive correlation with age, whereas phosphorus (P) and calcium (Ca) contents showed a negative correlation with age. In unburned roots, C, P and Ca contents also showed significant changes that were opposite of those observed in the crowns. In relation to sex, females exhibited a higher C ratio than males, whereas males showed significantly higher levels of oxygen (O), P and Ca in unburned roots. Incineration resulted in an increase in the crystallite size that correlated with increasing temperature. No differences in hydroxyapatite (HA) crystallite size were found between age groups; however, unburned teeth from females exhibited a larger crystallite size than did those from males. The challenges of using XRD with a 3D sample were overcome to allow analysis of whole teeth in a nondestructive manner. Further studies may be useful in helping predict the temperature of a fire.

Study of three types of desensitizers in dentin bonding strength.

One hundred and twenty human molars without decay (premolars and complete third molars) freshly extracted for orthodontic purposes were used in the study to explore the impact of application of three kinds of desensitizers on self-etching/all-etching bond strength of dentin. The roots were ground along the cementoenamel junction (CEJ), the residual crowns were divided into two parts along mesial and distal direction, and the enamel layer was removed. The dentin was ground into standard pieces of 3x3x3 mm and then polished using alumina waterproof abrasive paper. Two hundred and forty specimens were divided into two groups according to self-etching bond (OptiBond, iBond, XenoIV) and all-etching bond (OptiBond, iBond, Probond). Each of the two groups were subdivided into three groups with different brands, and then further subdivided into three experimental groups and a control group (10 samples in each final group). The surface of dentin coated with desensitizer was examined using scanning electron microscope. Results showed that only the shear strength of iBond + Ddes + Z100 resin group was lower compared to the control group (P < 0.05). The comparison of the resin shear strength in other experimental groups with the control groups demonstrated no statistically significant difference (P > 0.05). The shear strength of Optibond + Gluma, Optibond + Ddes, iBond + Ddes + Z100 resin group in all-etching bond group and the experimental groups in Probond group was lower than in the control group (P < 0.05). The resin shear strength in other groups did not differ from the controls (P > 0.05).

Biostimulation with diode laser positively regulates cementoblast functions, in vitro.

The aim of this study was to evaluate the effects of diode laser biostimulation on cementoblasts (OCCM.30). A total of 40 root plates were obtained from healthy third molar teeth and assigned to the following two groups: (1) control group and (2) laser-treated group. Root plates were placed into the cell culture inserts, and OCCM.30 cells were seeded onto root plates. Cells were irradiated with a low level of diode laser (power: 0.3 W in continuous wave, 60 s/cm2). Proliferation and mineralized tissue-associated gene's and BMP's messenger RNA (mRNA) expressions of cementoblasts were evaluated. Total RNAs were isolated on day 3 and integrin-binding sialoprotein (Ibsp), bone gamma-carboxyglutamate protein (Bglap), Type I collagen (Col1a1), osteoblastic transcription factor, runt-related transcription factor (Runx2), and Bone Morphogenetic Protein (BMP)-2, 3, 4, 6, and 7 mRNA expressions were determined using quantitative RT-PCR. von Kossa staining was performed to evaluate biomineralization of OCCM.30 cells. In the proliferation experiment, while there was no significant difference until 96 h, laser irradiation retarded the decrease in cell proliferation trend after 96 h compared to the untreated control group. Statistically significant increase in Ibsp, Bglap, and BMP-2,3,6,7 mRNA expressions were noted in the laser groups when compared to the untreated control group (p < 0.05). Laser irradiation induced mineralized nodule formation of cementoblasts. The results of this study reveal that the biostimulation setting of diode laser modulates the behavior of cementoblasts inducing mineralized tissue-associated gene's mRNA expressions and mineralization. Therefore, biostimulation can be used during regenerative periodontal therapies to trigger cells with periodontal attachment apparatus.

A Comparison of the Discoloration Potential for EndoSequence Bioceramic Root Repair Material Fast Set Putty and ProRoot MTA in Human Teeth: An In Vitro Study.

OBJECTIVE: To compare the discoloration potential of Endosequence Bioceramic Root Repair Material fast set putty (ERRMF) and ProRoot MTA (PMTA) when placed coronally in human extracted teeth over a 4-month period. METHODOLOGY: Forty-eight premolars were sectioned 2 mm below the cementoenamel junction. The pulp chambers were cleaned chemo-mechanically. The specimens were randomly assigned to three groups: PMTA, ERRMF, and no fill (control). Tooth color was measured spectrophotometrically at six time points: after material placement, after 2, 4, 8, 12, and 16 weeks. Data were transformed into Commission Internationale de l'éclairage (CIE) L*a*b* system and color difference values (ΔΕ) were calculated. Specimen images were recorded for each time point. Three random specimens from experimental groups were sectioned longitudinally and examined under a stereomicroscope. For data analyses, we used one-way analysis of variance with repeated measurements and Tukey's test (α = 0.05). RESULTS: At 2 weeks, the ΔE means did not differ significantly between the groups. At 4, 8, 12, and 16 weeks, PMTA group exhibited a significantly higher ΔE compared with the ERRMF and control groups. The ΔE did not differ significantly between the ERRMF and control groups. Teeth restored using PMTA exhibited a visually progressive dark discoloration. The control and ERRMF group specimens exhibited color stability. Sections of PMTA specimens revealed grayish discoloration of the material with dark dentinal staining that was not visible in the ERRMF specimens. CONCLUSION: Teeth restored using PMTA exhibited progressive discoloration, whereas teeth restored with ERRMF maintained color stability over a 4-month period. CLINICAL SIGNIFICANCE: The results found in the present study suggest that PMTA produces tooth discoloration over time, whereas ERRMF does not induce tooth discoloration. Therefore, ERRMF might be an alternative to PMTA, especially for coronal restoration in aesthetic zone teeth. (J Esthet Restor Dent 29:59-67, 2017).

Effects of different lasers on organic/inorganic ratio of radicular dentin.

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.

Effect of Lesion Baseline Severity and Mineral Distribution on Remineralization and Progression of Human and Bovine Dentin Caries Lesions.

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 (x0394;Z). Differences in mineral distribution between lesion types were apparent. Human dentin lesions were more prone to secondary demineralization (x0394;x0394;Z) than bovine dentin lesions, although there were no differences in x0394;L. 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 x0394;x0394;Z although bovine dentin lesions showed greater reduction in lesion depth L. For lesion types, responsiveness to remineralization (x0394;x0394;Z) 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.

Effect of polymer-based desensitizer with sodium fluoride on prevention of root dentin demineralization.

PURPOSE: To evaluate the effect of a fluoride-containing polymer-based desensitizer on prevention of root demineralization using micro-computed tomography (micro-CT). METHODS: Bovine root dentin blocks were divided into four groups; no treatment (Control); 1% oxalic acid (OA); MS Coat One containing methacrylate-co-p-styrene sulfonic acid (MS polymer) and 1% oxalic acid (MSO); and MS Coat F containing MS polymer, 1% oxalic acid and 3,000 ppm sodium fluoride (MSF). A window of the dentin surface was treated with each solution. The blocks were scanned using micro-CT after demineralization (pH 4.5, 5 hours). The dentin surfaces before and after demineralization were examined by scanning electron microscopy (SEM). Fluoride ion release was measured using a fluoride ion-specific electrode. The data were statistically analyzed using one-way ANOVA and Tukey's test (α = 0.05). RESULTS: MSF showed the lowest mineral loss (3176.5 ± 630.5 vol%µm), which was significantly different from Control (4600.1 ± 1053.4 vol%µm), OA (3992.7 ± 899.0 vol%µm) and MSO (3900.2 ± 645.4 vol%µm). [corrected]. Under the SEM observations, the dentin tubules appeared to be blocked after all desensitizer treatments. After demineralization, the exposure of dentin tubules was clearer in OA and MSO compared to MSF which showed sealed dentin tubules after demineralization. Fluoride ion release was detected only in the MSF group.

Racemization of aspartic acid in root dentin as a tool for age estimation in a Kuwaiti population.

Estimation of age is one of the most significant tasks in forensic practice. Amino acid racemization is considered one of the most reliable and accurate methods of age estimation and aspartic acid shows a high racemization reaction rate. The present study has investigated the application of aspartic acid racemization in age estimation in a Kuwaiti population using root dentin from a total of 89 upper first premolar teeth. The D/L ratio of aspartic acid was obtained by HPLC technique in a test group of 50 subjects and a linear regression line was established between aspartic acid racemization and age. The correlation coefficient (r) was 0.97, and the standard error of estimation was ±1.26 years. The racemization age "t" of each subject was calculated by applying the following formula: ln [(1 + D/L)/(1 - D/L)] = 0.003181 t + (-0.01591). When the proposed formula "estimated age t = ln [(1 + D/L)/(1 - D/L)] + 0.01591/0.003181" was applied to a validation group of 39 subjects, the range of error was less than one year in 82.1% of the cases and the standard error of estimation was ±1.12. The current work has established a reasonably significant correlation of the D-/L-aspartic acid ratio with age, and proposed an apparently reliable formula for calculating the age in Kuwaiti populations through aspartic acid racemization. Further research is required to find out whether similar findings are applicable to other ethnic populations.

In vitro evaluation of a novel biofilm remover.

OBJECTIVE: To evaluate a novel device for its efficacy in removing experimental biofilm from root surfaces and its potential for concomitantly removing/roughening the surface substance. METHODS AND MATERIALS: A novel acrylic rotary device (biofilm remover, BR) was tested in vitro in three experiments: surface loss, surface roughness [positive controls: Perioset (PS) and Proxoshape (PR)] and biofilm removal [positive controls: ultrasonic (US) and PS]. Surface loss/surface roughness was evaluated for dentin samples instrumented for three 20 s periods. The calcium removed during instrumentation was analysed after each interval and cumulatively, using atomic absorption spectrophotometry (AAS). Surface roughness was measured using profilometric analysis. Biofilm removal was evaluated on dentin specimens coated with a 64.5 h 6-species in vitro formed biofilm, after one 20 s treatment. Surface loss was analysed using anova with Scheffé post hoc test, and surface roughness/biofilm removal was analysed using Mann-Whitney test (all P ≤ 0.05). RESULTS: Significantly less substance loss [µg (± 1 SD)] was observed with the novel device at all time points, both interval and cumulative (1.0 (± 0.5) versus 9.3 (± 3.2) PS and 9.9 (± 1.9) PR at 60 s). Surface roughness [µm (95% CI)] was significantly lower for BR than for PS and PR [0.00 (-0.01, 0.08) 0.20 (0.16, 0.27) and 0.21 (0.19, 0.24) at 60 s]. Significantly less biofilm bacteria remained after treatment with both BR 4.5 (-0.1, 16.2) and US 1.9 (-0.2, 14.3), compared to PS 52 (27.9, 82.1). CONCLUSIONS: The novel biofilm remover was less damaging to dentin surfaces, while removing biofilm at least as effectively as devices used in this study.

Immunohistochemical localization of connective tissue growth factor, transforming growth factor-beta1 and phosphorylated-smad2/3 in the developing periodontium of rats.

BACKGROUND AND OBJECTIVE: Connective tissue growth factor (CTGF) is a downstream mediator of transforming growth factor-beta1 (TGF-ß1), and TGF-ß1-induced CTGF expression is regulated through the SMAD pathway. CTGF is implicated in the development of cartilage, bone and tooth. However, its expression in the developing periodontium is unclear. Therefore, we aimed to investigate the immunolocalization of CTGF, TGF-ß1 and phosphorylated SMAD2/3 (pSMAD2/3) in the developing periodontium of rats. MATERIAL AND METHODS: The maxillaries of Wistar rats, 2, 3, 7 and 12 wk of age, were used and the localization of CTGF, TGF-ß1 and pSMAD2/3 was detected using immunoperoxidase techniques. RESULTS: Hertwig' s epithelial root sheath (HERS) cells were strongly positive for CTGF and TGF-ß1, but not for pSMAD2/3. Positive staining for CTGF, TGF-ß1 and pSMAD2/3 was found in bone and periodontal ligament. In cementum, most cementoblasts associated with cellular cementum and some cementocytes stained strongly for CTGF, whereas cementoblasts associated with acellular cementum did not express CTGF. No signal for TGF-ß1 was observed in cellular and acellular cementum. In addition, most cementocytes were strongly positive for pSMAD2/3. CONCLUSION: CTGF, TGF-ß1 and pSMAD2/3 are localized in bone and periodontal ligament, but are differentially expressed in HERS and cementum. The results of our study indicate that the regulation of CTGF expression by TGF-ß1 might be cell-type specific in periodontium.

Application of the Bang and Ramm age at death estimation method to two known-age archaeological assemblages.

The Bang and Ramm method uses root dentine translucency (RDT) length in sectioned or unsectioned teeth as a sole indicator of chronological age at death in adult human remains. The formulae have been tested on modern remains of known age and on modern and archaeological remains of unknown age. This is the first published study of the method on known-age archaeological specimens and tests whether RDT is a good indicator of chronological age in buried human remains. We applied the Bang and Ramm equations to two 18th and 19th century assemblages excavated from the crypt of Christ Church, Spitalfields, and the cemetery of All Hallows by the Tower. Translucency was defined by shining a light through the external unsectioned root surface and was measured from digital images of 583 and 83 nonmolar roots from 126 Spitalfields and 12 All Hallows individuals, respectively, aged 21-81 years. Average absolute difference between real age and estimated age was 10.7 years and 8.4 years for Spitalfields and All Hallows individuals, respectively, with 58% and 75% estimated within 10 years of known age, and 29% and 33% estimated within five years of known age. These estimations are comparable to results from other ageing methods applied to the Spitalfields collection. Ages from both populations were estimated largely to the middle ranges, with younger individuals overestimated and older individuals underestimated. This is a common occurrence when using inverse calibration, where age is treated as the dependent variable and the ageing feature as the independent variable.

Porosity and root dentine to material interface assessment of calcium silicate-based root-end filling materials.

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.