Cement-enamel Junction Research Articles

Oral Health Status at Age 60 and 72 Years-A Longitudinal Study.

This study investigated oral health status in 60-year-old individuals over 12 years. Data were obtained from The Swedish National Study on Aging and Care (SNAC). One hundred nineteen 60-year-old individuals (48% females) underwent a clinical and radiographic baseline examination (2001-2003) and follow-up examination in 2013-2015. For statistical analyses, paired t-tests and McNemar's test were performed. Statistical significance was determined at p < 0.05. At the 12-year follow-up, the mean number of teeth and the proportion of individuals having ≥ 20 teeth decreased (p < 0.001). The mean number of teeth with buccal/lingual and approximal caries lesions increased (p < 0.029 and p < 0.031). Individuals with a distance from the cement-enamel junction to the bone of ≥ 5 mm increased in total (p < 0.002) and in males (p < 0.006). The prevalence of gingivitis increased in total (p < 0.001). The prevalence of periodontitis showed a significant increase in total (p < 0.043) and in females (p < 0.039). The present study indicates that oral health status in 60-year-old individuals deteriorates over 12 years. However, the deteriorations were minor in terms of tooth loss, caries lesions, and changes in periodontal status.

Evaluation of Shear Bond Strength of Universal Adhesives to Dentin: in Vitro Study

Aim: Universal adhesives are widely used in restorative dentistry. The aim of this study was to evaluate the shear bond strength (SBS) of universal adhesives to dentin in different application modes. Materials and Methods: The study utilized seven universal adhesives and one total-etch adhesive. The sixty-four extracted intact human molars used in the study were embedded in acrylic blocks to the enamel-cement junction. The occlusal surface was removed to expose the dentin surface. After applying self-etch and total-etch adhesives to the dentin, flowable composite (Clearfil Majesty Flow, Kuraray) was placed in a transparent mold (2.38 mm diameter and 2 mm height) and polymerized. After thermal aging (1000 cycles), a SBS test has been carried out on a universal testing machine. The fracture types formed on the surface of the teeth were examined under a microscope. Data were analyzed by two-way analysis of variance (ANOVA) test (p&lt;0.05). Results: SBS values of universal adhesives on dentin showed statistically significant differences according to adhesive and application mode (p&lt;0.05). Total-etch application produced statistically higher SBS than self-etch application (p&lt;0.05). The two-step universal adhesive (G2 Bond Universal) had the highest SBS in both the self-etch and total-etch application modes (p&lt;0.05). When the bond surfaces of the universal adhesives were examined, fractures occurred most frequently in the adhesive type. Conclusion: The use of universal adhesives in the total-etch mode results in greater bond strength to dentin tissue. Universal adhesive type influences bond strength.

Three-Dimensional Internal Voids and Marginal Adaptation in Deep Margin Elevation Technique: Efficiency of Highly Filled Flowable Composites.

To evaluate interfacial three-dimensional adaptation and internal voids of different flowable materials before and after cyclic fatigue in a simulated deep-margin elevation scenario. Eighty (n &#61; 80) extracted premolars were selected and two Class II cavities were prepared. The mesial one with cervical margin 1 mm above the cementum-enamel junction (CEJ) and the distal one with cervical margin 1 mm below the CEJ. After performing adhesive procedures, specimens were divided into four groups according to the employed materials for 2 mm horizontal deep-margin relocation: nanohybrid composite (Clearfil ES2, Kuraray); conventional viscosity flowable composite (Tetric Flow, Ivoclar); medium viscosity flowable composite (Majesty ES2 Low Flow, Kuraray); high viscosity flowable composite (Majesty ES2 Super Low Flow, Kuraray). All restorations were finalized by oblique layering with nanohybrid composite (Clearfil ES2, Kuraray). To reveal interfacial and internal gap progression, specimens were scanned with a micro-CT (SkyScan 1172), before and after 500,000 cycles of mechanical chewing simulation (50 N, 1 Hz). Data were imported into Mimics software after smoothing and region growing. Only the 2 mm margin relocation volumes were considered. Obtained masks were analyzed for noise removal and volume calculation. At baseline, interfacial gap progression and internal voids, expressed in mm3, were collected and statistically analyzed with two-way ANOVA (α 0.05) for the variables substrate and restorative materials followed by Tukey post-hoc test. An additional two-way ANOVA test, followed by Tukey post-hoc test, was performed to evaluate variation in interfacial gap progression after mechanical aging. At baseline, the ANOVA test showed a significant difference for the variable restorative materials (p &#61; 0.01). More specifically, the Tukey post-hoc test revealed that the highly filled medium viscosity composite performed better than the conventional viscosity composite at baseline for the interfacial gap. The internal voids ANOVA test at baseline reported no significant differences for the variable tested. Analysis of variance for internal gap progression after thermocycling showed no differences for both substrate and restorative material employed. Highly filled medium viscosity composite performed significantly better than the conventional viscosity flowable composite for what concern baseline interfacial gaps. Artificial aging with a chewing simulator and thermocycling did not affect interfacial gap progression on enamel and dentin. The tested restorative materials performed equally after aging.

Oro-Dental Characteristics in Patients With Adult-Onset Hypophosphatasia Compared to a Healthy Control Group-A Case-Control Study.

Hypophosphatasia (HPP) is a rare inherited disease that affects multiple organ systems including bone and teeth. Limited knowledge exists on dental and oral health in patients with adult-onset HPP (aHPP). The aim of this study was to investigate oro-dental characteristics in patients with aHPP compared to healthy controls. This case-control study included 20 patients with aHPP compared to 31 healthy controls. Oro-dental manifestations were examined by standardised interviews, clinical examinations as well as radiological registrations on panoramic radiograph (OP) and cone-beam computed tomography (CBCT) scans. The subjective experience of tooth fractures (p = 0.010), caries in permanent teeth (p = 0.032) and early loss of permanent teeth (p = 0.002) was significantly higher in patients with aHPP compared to the controls. In the aHPP group, the presence of specific teeth (p ≤ 0.045) and attrition of 11 were significantly lower (p = 0.012) compared to the controls. Opacity of a few teeth (p ≤ 0.049), presence of denticles (p = 0.024), the distance between the enamel-cement junction (CEJ) and the marginal bone level at specific sites (p ≤ 0.021) and crown height of 11 (p = 0.017) were significantly higher in patients with aHPP than in healthy controls. The results indicate that patients with aHPP have a subjective experience of having poorer dental health. Loss of permanent teeth, less attrition, tooth opacities, denticles and larger distance between CEJ and marginal bone level are possible oro-dental findings in patients with aHPP.

Evaluation Of Bone Thickness At Different Anatomical Sites In Infrazygomatic Crest For Miniscrew Insertion In Skeletal Class II Patients – A CBCT Study

AIM: To assess infrazygomatic crest bone thickness at different anatomical sites at a distance of 5mm, 7mm, 9mm and 11mm apical to cementoenamel junction, 70 degree to occlusal plane in skeletal class II patients using cone beam computed tomography (CBCT). Materials and Methods: The sample consists of cone beam computed tomography images of 23 class II subjects were evaluated. Infrazygomatic crest bone thickness was evaluated at the six horizontal regions (i) interdental area between maxillary second premolar (PM2) and first molar(M1) (ii) Mesiobuccal root of maxillary first molar (MB root of M1) (iii) Distobuccal root of maxillary first molar(DB root of M1) (iv) interdental area between maxillary first molar(M1) and second molar(M2) (v) Mesiobuccal root of maxillary second molar(MB root of M2) (vi) Distobuccal root of maxillary second molar (DB root of M2) at a vertical distance of 5mm,7mm,9mm and 11mm apical to cementoenamel junction, 70 degree to occlusal plane. Results: The buccal bone thickness increase from mesial surface of maxillary first molar to mesial surface of maxillary second molar from cement enamel junction at the level of 11mm, 70 degree to the occlusal plane. The bone thickness decreases at the second molar level. Conclusion: The safe site for insertion of miniscrews in the infrazygomatic crest were the interdental region between the maxillary first and second molars at the heights of 11 mm from cementoenamel junction and 70 degree to the occlusal plane

Umbelliferone reduces inflammation and ligature-induced osteoclastic alveolar bone resorption in mice.

This study aimed to investigate the effects of Umbelliferone (UMB) on the inflammation underlying alveolar bone resorption in mouse periodontitis. Male Swiss mice subjected to a ligature of molars were grouped as non-treated (NT), received UMB (15, 45, or 135 mg/kg) or saline daily for 7 days, respectively, and were compared with naïve mice as control. Gingival tissues were evaluated by myeloperoxidase (MPO) activity and interleukin-1β level by ELISA. The bone resorption was directly assessed on the region between the cement-enamel junction and the alveolar bone crest. Microscopically, histomorphometry of the furcation region, immunofluorescence for nuclear factor-kappa B (NF-ĸB), and immunohistochemistry for tartrate-resistant acid phosphatase (TRAP), and cathepsin K (CTSK) were performed. Systemically, body mass variation and leukogram were analyzed. Periodontitis significantly increased MPO activity, interleukin-1β level, and NF-ĸB+ immunofluorescence, and induced severe alveolar bone and furcation resorptions, besides increased TRAP+ and CTSK+ cells compared with naïve. UMB significantly prevented the inflammation by reducing MPO activity, interleukin-1β level, and NF-ĸB+ intensity, besides reduction of resorption of alveolar bone and furcation area, and TRAP+ and CTSK+ cells compared with the NT group. Periodontitis or UMB treatment did not affect the animals systemically. UMB improved periodontitis by reducing inflammation and bone markers.

Cone-Beam Computerized Tomography as a Tool for Greater Palatine Foramen and Greater Palatine Sulcus Detection

This study aimed in evaluates the position of the greater palatine sulcus and foramen, according to confounding factors, using cone-beam computerized tomography. The great palatine foramen and greater palatine sulcus were located at 105 maxillary cone-beam computerized tomography and the distance to the cement-enamel junction at the first and second premolars and the first molar were measured. A step-wise multiple regression analysis was used to data analysis. The great palatine foramen was most frequently located in the regions between the second and third molar and no influence of variables were noted (p&gt;0.05). The mean distance between the greater palatine sulcus and cement-enamel junction was 15.3±2.3 mm. However, a shorter distance was observed in females (p&lt;0.0001) and in those lowvault subjects (p&lt;0.05). The location of the greater palatine sulcus appears to be affected by gender and palatal type, i.e., female and low-vault subjects presented the artery closer to the cement-enamel junction.

Intraoral Ultrasound Imaging Using a Rotational Transducer with Periodontal Feature Identification by Machine Learning.

Innovative intraoral ultrasound devices with smart artificial intelligence-based identification for dento-anatomy could provide crucial information for oral health diagnosis and treatment and shed light on real-time detection of developmental dentistry. However, the grand challenge is that the current ultrasound technologies are meant for external use due to their bulkiness and low frequency. We report a compact versatile ultrasound intraoral device that consists of a rotational probe head robustly pivoted around a hand-held and portable handle for real-time imaging of intraoral anatomy using high-frequency ultrasonography (up to 25 MHz). The intraoral ultrasound device that could be adjusted for various orientations of the imaging planes by rotating the head provides real-time, high-resolution ultrasonograms of intraoral structures, including dento-periodontium of most tooth types and maxillary palate. Machine learning-based algorithms are integrated to automate the identification of important structures, including alveolar bone and cementum-enamel junction. The intraoral ultrasound device smartened with artificial intelligence could innovate oral health diagnosis and treatment plans toward precision health and patient care.

Periodontal evaluation after maxillary expansion with atooth-bone-borne expander in growing patients : Arandomized clinical trial.

This two-arm parallel randomized controlled trial aimed to evaluate and compare periodontal changes due to rapid maxillary expansion (RME) using tooth-bone-borne and tooth-borne devices in growing patients via clinical examinations and cone-beam computed tomography (CBCT). Forty-two eligible patients (aged 11-14years; transverse maxillary deficiency, posterior crossbite) were screened and divided into two groups based on the treatment received (randomization was performed using computer-generated numeric sequences): hybrid hyrax tooth-bone-borne group (TBB) and hyrax tooth-borne group (TB). The primary outcome was the change in cortical bone thickness (by CBCT). In addition, the clinical attachment level (CAL), gingival recession, and bleeding were assessed. Both examinations were performed before and 3months after the activation phase. Intergroup comparisons were performed using analysis of covariance (ANCOVA; P < 0.05). Twenty-one patients (12girls and 9boys; mean initial age, 13.3years) were included in the TBB group and 21 (5girls and 16boys; mean initial age, 13.2years) were included in the TB group. The TB group exhibited adecrease in buccal bone thickness in the first premolars and first molars at all three evaluated levels. Specifically, tooth 14 at 3 mm from the enamel-cement junction showed asignificant width reduction (0.7 mm; p < 0.001), accompanied by anotable increase in palatal cortical thickness at 6 mm of enamel-cement junction (1.13 mm; p < 0.001). RME resulted in buccal bone thickness reduction at the first premolar with hyrax treatment. In the molar region, both devices resulted in cortical bone alterations that were less pronounced in the TBB group.

Microleakage Assessment of Single Cone Gutta Percha Obturation Technique Using Different Types of Sealers

This study was carried out to compare the coronal and apical seal of canals obturated with single cone technique using different types of epoxy resin root canal sealers. A total of sixty extracted human upper molars with fully formed and sound palatal roots were used in this study. The crown of each tooth was decoronated at cement-enamel junction and the palatal root canal was prepared using ProTaper gold rotary instruments. Sixty specimens were used and divided into 3 equal groups(n=20) for single cone obturation using two different types of epoxy resin sealers AH26 and vioseal sealers respectively and one control group without sealer. All the specimens were exposed varnish application followed by dye penetration test using 2% methylene blue dye then root sectioning. Samples were evaluated under a stereomicroscope to detect the linear measurement of the dye penetration from the apical constriction. The image transferred to a computer equipped with the image analysis software program where the dye penetration along the filling dentine interface was evaluated. The collected data was statistically analysis by using Graph Pad Instat software for windows. One-way ANOVA was done for compared results followed by Tukey’s pair-wise. The results showed that, the difference in dye penetration microleakage means between groups was statistically significant as revealed by one-way ANOVA test (p &lt; 0.05). Pair-wise Tukey’s post-hoc test showed non-significant (p&gt;0.05) difference between (AH26 and Vioseal sealers) groups. None of the tested root canal sealers could eliminate the dye infiltration or microleakage formation. Single cone gutta-percha combined with AH26 sealer exhibited less microleakage than vioseal sealer although there were no statically significant differences between them.

Tissue Dissolution Ability of Sodium Hypochlorite, EDTA, Ambroxol Hydrochloride and Triphala Evaluated and Compared when used as an Irrigant on Bovine Pulp Tissue

Aim: The aim of the study is to evaluate pulp tissue dissolution ability of Sodium hypochlorite (NaOCl), Ethylenediaminetetraacetate (EDTA), Ambroxol hydrochloride and Triphala.  Methods: Pulp tissue of BOS Taurus primigenius was extracted from 20 mandibular incisors of 4 bovine jaws .Decoronation was done at the cementum–enamel junction and roots were resected at a length of 3 mm from the apex with a diamond disc connected to a electric micromotor. Pulp tissue was then taken out of the pulp chamber of the bovine tooth with a periodontal probe and cotton pliers. Specimens were weighed using a hermetic precision electronic balance (AND Company LTD) before the test to analyze the initial weight (T0) of the samples. Extracted bovine pulp tissue specimens were weighed and randomly distributed in to 4 experimental groups of 3% sodium hypochlorite, 17% EDTA, Ambroxol hydrochloride(35mg/ml), Triphala(100mg/ml) that were taken in 4 centrifugation tubes. Contents are filtered and undissolved tissue remnants collected and reweighed.  Results: Results obtained indicate that highest pulp dissolution is for NaOCl, followed by EDTA, Ambroxol Hydrochloride and least for Triphala.  Conclusion: Highest pulp dissolution is for NaOCl, followed by EDTA, Ambroxol Hydrochloride and least for Triphala.

A Minimally Invasive Surgical Procedure to Harvest Palate Periosteum as a Source of Mesenchymal Stromal/Stem Cells for Bone Tissue Engineering.

The aim of this study is to validate a minimally invasive surgical procedure to harvest palate periosteum as a source of tissue for mesenchymal stromal/stem cells. We performed a standardized procedure to harvest the palate periosteum in ten subjects, which consisted of a 3 mm disposable punch and a Molt periosteal elevator to harvest a small full-thickness fragment of soft tissue at the hard palate area, between the upper bicuspids, 3 to 4 mm apical to the cement enamel junction. The one-third inner portion was fragmented, and following standard cell culture procedures, the adherent cells were cultured for three passages, after obtaining 70-90% confluence. Cell morphology analysis, flow cytometry analysis, and viability and osteogenic differentiation assays were performed. In all 10 cases, uneventful healing was observed, with no need for analgesic intake. The evaluation of cell morphology showed elongated spindle-shaped cells distributed in woven patterns. A high viability range was verified as well as an immunophenotype compatible with mesenchymal stem cell lineage. The differentiation assay showed the potential of the cells to differentiate into the osteogenic lineage. These results demonstrate that the minimally invasive proposed surgical technique is capable of supplying enough periosteum source tissue for stem cell culture and bone tissue engineering.

Enamel surface roughness following debonding resin clean up using high speed air-turbine and electric handpieces. In vitro study

BackgroundHigh speed electric handpieces have recently been growing in popularity among dental professionals. Advantages include smoother surface preparation and increased cutting efficiency.AimThe primary objective was to compare enamel surface roughness following resin cleanup after bracket debonding using highspeed air turbine versus electric handpiece. The secondary objective was to record the time needed for resin-clean up.MethodForty deidentified freshly extracted human premolars were cleaned and sectioned at the cement-enamel junction. The crowns were embedded in acrylic blocks. Enamel surface roughness parameters (Ra, Rz, Rp and Rv) were measured using a stylus profilometer. Brackets were bonded using a light-cure orthodontic adhesive and stored in distilled water for 24 h. Following bracket debonding, the specimens were randomly divided into 2 groups: First group: resin clean-up was carried out using a 12-fluted carbide bur mounted on a high-speed air turbine; and second group: where an electric handpiece was used. Surface roughness parameters were measured following resin clean up and after polishing using pumice and a rubber cup. Time needed for resin clean-up was recorded. Differences in enamel surface roughness and time between groups were compared using repeated measures ANOVA and independent samples t-test, respectively at P ≤ 0.05.ResultsThe electric handpiece groups showed significantly higher values for Ra, Rz and Rp both following resin cleanup and polishing. Time taken for resin cleanup was significantly longer for the electric handpiece group.ConclusionConsidering both surface roughness and time, electric handpiece do not seem to add greater effectiveness or efficiency to resin cleanup following orthodontic bracket debonding.

An In-Vitro Study to Find the of Frequency of MB2 Canal in Permanent Maxillary Molars

Present in-vitro research conducted to find out the frequency of second mesiobuccal canals in permanent maxillary molars. Eighty extracted, intact maxillary permanent molars were selected for the present study. Following that, a slow-speed diamond disc was used to divide the occlusal sections of the crowns at the cement-enamel junction. Using a safe-end diamond bur, overhanging dentin that covered the canal orifices was removed to allow straight line visibility. Under an x8 magnification, the teeth were photographed from their occlusal side. Result showed that the first and second maxillary molars, MB2 canals were found in 70% and 55%, respectively. In conclusion it is crucial during endodontic procedures on maxillary molars to cautiously check pulpal floor to detect any "extra" canals, notably the second mesiobuccal canal, by scraping away the constrictive dentin above the orifices.

In vitro evaluation of the bleaching effect on the change of color match of omnichroma composite resin

Aim To in vitro evaluate the bleaching effect on the color match of Omnichroma composite resin restorations to the teeth color. Materials and methods Thirty freshly extracted intact human premolars were collected and mounted in acrylic resin blocks (only roots were embedded). The shade of the selected teeth was measured by (VITA Easyshade V). Class V cavities (4 mm width, 2 mm length, and 2 mm depth) were prepared 2 mm coronal to cement-enamel junction on the cervical third of the facial surface of each tooth. Specimens were randomly divided into two equal groups (n = 15): group I: was restored with nano hybrid Tetric N- ceram while group II: was restored with Omnichroma supra-nano filled composite resin using their respective adhesives. All the specimens were thermocycled for 500 cycles from 5 to 55°C with 15 s dwell time, and 20 s transfer time. The initial data of color measurements for tooth and restoration surfaces were recorded after thermocycling using VITA Easy Shade V. Specimens were then bleached using 40% HP by White smile power whitening YF according to the manufacturer instructions and kept in artificial saliva for 1 week before color re-measuring. All data were collected, tabulated, and statistically analyzed at 95% significance level using a software statistical package for social sciences (SPSS version 26). Results Before bleaching, higher mean ΔΕ values were recorded for the teeth (3.38 and 2.74) compared to (2.24 and 1.82) of the restorations in group I (Tetric N) and group II (Omnichroma) respectively with no statistically significant difference (P = 0.26 and 0.43) in either of the groups denoting the color match between the restorations and the teeth in both groups. After bleaching there was a highly statistically significant difference (P = 0.039) between the mean ΔΕ values of teeth (5.56) and restorations (3.23) in group I, denoting the color mismatch. While in group II there was no significant difference (P = 0.249) between the values of teeth (5.25) and restorations (4.49) denoting the persistence of the color match after bleaching. No significant difference was found between the ΔΕ values of teeth used in both groups neither before (P = 0.62) nor after bleaching (P = 0.802). While there was a significant difference between the recorded values of the restorations after bleaching (P = 0.026) although the difference was not significant before bleaching (P = 0.619). Bleaching significantly affected the teeth color (P = 0.013 and 0.038), and the restoration color (P = 0.049 and 0.012) in groups I and II, respectively. Conclusions Omnichroma class V composite restorations matched the shades of teeth before and after bleaching where it was changed to a lighter shade with the teeth enamel that was within the acceptable clinical range. The color matching of the Tetric N restorations after bleaching was lost where the teeth were lighter in a clinically detectable manner, which necessitates restoration replacement.

In Vitro Analysis of Outcome Differences Between Repairing and Replacing Broken Dental Restorations.

Objective In light of several advancements and considerations in endodontic dentistry, there still remains a need to comprehensively evaluate the outcome disparities between repairing and replacing broken dental restorations. This study aims to compare the effectiveness of repairing dental restorations versus replacing them, focusing on how each method affects the structural strength and longevity of the restorations. Methods The study included 60 freshly removed human maxillary premolars. Initial processing involved rigorous washing, descaling, and polishing of the teeth. To ensure preservation, the specimens were stored in sterile, distilled water. To occlude the root canals, a self-hardening composite resin was used, and the roots were coated with two coats of clear nail polish to prevent moisture penetration. A 245 carbide bur attached to a high-speed dental handpiece with air and water spray cooling produced standardized Class II cavities on the occluso-proximal surfaces. Each cavity had a buccolingual breadth of 2 mm, an occluso-cervical length of 4 mm, and a gingival boundary that was 1 mm coronal to the cement-enamel junction. Following this preparation, the teeth were randomly separated into three groups (Group A, Group B, and Group C), each containing 20 teeth. Results Our analysis showed that teeth with entirely replaced restorations had a higher average fracture resistance than those with repaired restorations. However, the difference in fracture resistance between the repair and replacement groups for each type of material was not statistically significant. Conclusion Based on the findings, repairing a dental restoration can be a conservative and less invasive alternative to a full replacement without a significant compromise in the restoration's ability to withstand fracture. Therefore, dental professionals might consider full restoration as a viable option, taking into account the need to preserve dental tissue as well as the restoration's durability and structural integrity.

Marginal adaptation of bulk-fill resin composites with different viscosities in class II restorations: a micro-CT evaluation

BackgroundThe purpose of this study is to evaluate the marginal adaptation of bulk-fill resin composites with different viscosities (paste-like and flowable) in Class II restorations using micro-CT imaging.MethodsForty extracted human molars were used. Mesial and distal Class II box cavities (approximately 3 mm x 3 mm x 4 mm) were prepared for each tooth, with cavity floors located 1 mm below the enamel-cementum junction. Following adhesive application, teeth were restored using eight different groups: Group XB: X-tra Base Bulk-fill Flowable (VOCO), Group XF: X-tra Fill Bulk-fill (VOCO), Group FB: Filtek Bulk-fill Posterior (3 M ESPE), Group FF: Filtek Bulk-fill Flowable (3 M ESPE), Group BB: Beautifil-Bulk (SHOFU), Group BF: Beautifil-Bulk Flowable (SHOFU), and Group CO: “as a control group”, Clearfil Majesty Posterior (KURARAY) and Group CF: “as a control group”, Clearfil Majesty Flow + Clearfil Majesty Posterior (KURARAY). The restored teeth underwent an aging protocol involving 1000 cycles in a water bath fluctuating between 5 ± 1.0 °C and 55 ± 1.0 °C. Post-aging, teeth were immersed in 50% silver nitrate solution for 24 h and then in a film developer solution for 8 h. Microleakage analysis was performed using micro-CT, evaluated with 3D Slicer software. A two-way ANOVA was employed for statistical analysis.ResultsTwo-way ANOVA results indicated significant effects of both viscosity (p < 0.0001) and composite type (p < 0.0001) on marginal adaptation. Viscosity analysis (comparing flowable and paste-like) revealed no significant differences in the FB-FF, XB-XF and BB-BF groups but significant differences in the and CO-CF group, with flowable type exhibiting less microleakage than paste-like type.ConclusionsThe study suggests that while the viscosity of bulk-fill composites did not significantly affect marginal adaptation, the brand of bulk-fill composite did influence it.

Oxytocin alleviates periodontitis in adult rats.

The objective of the study was to evaluate the expression of oxytocin receptors in normal and inflamed gingiva, as well as the effects of systemic administration of oxytocin in bone loss and gum inflammatory mediators in a rat model of experimental periodontitis. Current evidence supports the hypothesis of a disbalance between the oral microbiota and the host's immune response in the pathogenesis of periodontitis. Increased complexity of the microbial biofilm present in the periodontal pocket leads to local production of nitrogen and oxygen-reactive species, cytokines, chemokines, and other proinflammatory mediators which contribute to periodontal tissue destruction and bone loss. Oxytocin has been suggested to participate in the modulation of immune and inflammatory processes. We have previously shown that oxytocin, nitric oxide, and endocannabinoid system interact providing a mechanism of regulation for systemic inflammation. Here, we aimed at investigating not only the presence and levels of expression of oxytocin receptors on healthy and inflamed gingiva, but also the effects of oxytocin treatment on alveolar bone loss, and systemic and gum expression of inflammatory mediators involved in periodontal tissue damage using ligature-induced periodontitis. Therefore, anti-inflammatory strategies oriented at modulating the host's immune response could be valuable adjuvants to the main treatment of periodontal disease. We used an animal model of ligature-induced periodontitis involving the placement of a linen thread (Barbour flax 100% linen suture, No. 50; size 2/0) ligature around the neck of first lower molars of adult male rats. The ligature was left in place during the entire experiment (7 days) until euthanasia. Animals with periodontitis received daily treatment with oxytocin (OXT, 1000 μg/kg, sc.) or vehicle and/or atosiban (3 mg/kg, sc.), an antagonist of oxytocin receptors. The distance between the cement-enamel junction and the alveolar bone crest was measured in stained hemimandibles in the long axis of both buccal and lingual surfaces of both inferior first molars using a caliper. TNF-α levels in plasma were determined using specific rat enzyme-linked immunosorbent assays (ELISA). OXT receptors, IL-6, IL-1β, and TNF-α expression were determined in gingival tissues by semiquantitative or real-time PCR. We show that oxytocin receptors are expressed in normal and inflamed gingival tissues in male rats. We also show that the systemic administration of oxytocin prevents the experimental periodontitis-induced increased gum expression of oxytocin receptors, TNF-α, IL-6, and IL-1β (p < .05). Furthermore, we observed a reduction in bone loss in rats treated with oxytocin in our model. Our results demonstrate that oxytocin is a novel and potent modulator of the gingival inflammatory process together with bone loss preventing effects in an experimental model of ligature-induced periodontitis.

Deleterious effect of chronic high-dose ethanol intake on biomechanical bone properties and periodontal status.

To evaluate the effect of high-graduation chronic ethanol (EtOH) intake on bone and periodontal tissues of rats. Male Wistar rats (250g) were divided into two groups of n = 12 each one. EtOH (5ml of 3g/kg) was administered to the experimental group by gastric gavage twice a day for 20days and the control group received water under the same conditions. The rats were euthanized and used to perform biochemical determination in plasma and gingival tissue, and histological and biomechanical studies in the femur and mandibular tissues. Alcohol increased both TNFα (p < 0.01) and PGE2 (p < 0.05) in plasma and gingiva (p < 0.05) as compared to controls. In addition, EtOH increased the alveolar bone loss as evidenced by the increased distance between the cement enamel junction and the alveolar crest (p < 0.01), the lower % of interradicular bone expressed as bone area/total area (B.Ar/T.Ar, p < 0.05) and the larger periodontal space (p < 0.05), as compared to controls. Likewise, the mandibular microtomographic analysis in alcoholized rats revealed a lower % of interradicular bone volume/total volume (BV/TV, p < 0.05), greater trabecular separation (p < 0.05) and greater % trabecular porosity (p < 0.05) than controls. No biomechanical alteration was observed in lower jaws, while the femur of alcoholized rats presented a decrease in the structural bone properties (p < 0.001), as a systemic consequence of deterioration of the diaphyseal architecture (p < 0.01) without changes in material properties. The consumption of high doses of alcohol produces deleterious effects on periodontal tissues that could be due not only to local but also systemic effects.

Ten-month In Vitro Study of Marginal Adaptation and Micropermeability in Class II Restorations Made with Matrix-modified Composites

The aim of the present in vitro study was to compare the marginal adaptation and micropermeability of class II restorations with a gingival wall, located 1 mm below the enamel-cementum junction, restored with two conventional dimethacrylate composites (Filtek P60 and Filtek Ultimate), and two innovative composites with a modified polymer matrix (Venus Diamond and Kalore) over ten months of ageing. The marginal adaptation to the proximal margins of the cavity was analyzed and evaluated by the SEM. The dye method was used to assess the micropermeability, and the analysis was performed using a stereomicroscope. The same samples were used for both studies. A correlation analysis was done based on the data to establish the relationships between marginal adaptation and micropermeability. A statistically significant difference in the estimates for marginal adaptation of materials to the gingival, vestibular, and lingual proximal edges for values of excellent marginal adaptation ($$p&lt;0.005$$) was found. F.P60 differed significantly from V. Diamond and F. Ultimate. Kalore is arranged in the middle and does not differ considerably from the above two groups. According to micro permeability, a significant difference was found between F. Ultimate with better results and F.P60 and Kalore ($$p&lt;0.005$$). There was a significant correlation ($$p=0.008$$) between the excellent scores for marginal adaptation to the edge of the gingival wall and micropermeability. It can be concluded that innovative high-molecular-weight composites do not significantly improve marginal adaptation and micropermeability in class II cavities, with a gingival wall located entirely in dentin.