The Influence of Adalimumab on the Healing of Apical Periodontitis in Ferrets

Introduction

Given the increasing use of anti–tumor necrosis factor α (anti-TNFα) biologic medications, and their interferences with the immune-inflammatory response, this study evaluated the effect of adalimumab (anti-TNFα), on healing and healing time of apical periodontitis (AP) in ferrets.

Effect of the implant–abutment interface on peri-implant tissues: A systematic review

Objective. The aim of the present systematic review was to determine the peri-implant tissue response to different implant abutment materials and designs available and to assess the impact of tissue biotype. Materials and methods. Relevant literature published between December 2009 and August 2012 was searched to identify studies dealing with different implant abutment designs and materials, as well as the response of different tissue biotypes. The search terms used, in simple or multiple conjunctions, were ‘implant abutment', ‘interface', ‘material', ‘peri-implant', ‘soft tissue' and ‘esthetic'. Studies were selected according to pre-determined inclusion and exclusion criteria. Results. The initial search yielded 2449 titles. After a subsequent filtering process, 23 studies were finally selected. The included studies revealed different factors responsible for the stability of peri-implant tissue and the esthetic outcome. These factors include tissue biotype and architecture, implant abutment material and implant abutment design. Several designs were suggested to prevent marginal bone loss and soft tissue recession. These included scalloped implants, platform-switched implants and gingivally converged or concave implant abutments. Due to the limited number of studies and the heterogeneity in their designs, it was not possible to perform a statistical analysis of the data. Conclusions. The current literature provides insufficient evidence about the effectiveness of different implant abutment designs and materials in the stability of peri-implant tissues.     

Effect of Ag on the corrosion behavior of Ti–Ag alloys in artificial saliva solutions

ObjectivesThe purpose of this study was to investigate the corrosion behavior of Ti–Ag alloys in artificial saliva solutions.MethodsThe corrosion behavior of experimental Ti–Ag alloys in artificial saliva was examined by means of potentiodynamic polarization measurements. The surface passive film formed was analyzed by means of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) methods.ResultsThe alloys were found to develop surface passive films after immersion for 1.8 × 10³ s. In comparison with commercially pure Ti, the Ti–Ag alloys exhibited better corrosion resistance with lower anodic current densities, larger polarization resistances, and higher open-circuit potentials. The passive film formed was predominantly composed of TiO₂, as determined by XPS. When fluoride ions were added in the solution, the TiO₂ passive film was destroyed and Na₂TiF₆ was formed.SignificanceAddition of Ag was found to be effective in reducing the corrosion current density and increasing the open circuit potential of titanium in artificial saliva environment. Addition of fluoride ions in the solution severely reduced the corrosion resistance of Ti–Ag alloys.     

Effect of the Progression of Fusobacterium nucleatum–induced Apical Periodontitis on the Gut Microbiota

IntroductionFusobacterium nucleatum, which is involved in the development of periodontal disease and apical lesions, can be transmitted to the colon and metastasize to colorectal cancer, suggesting a link between oral and systemic diseases. We analyzed the effects of F. nucleatum on bacterial flora in the gut and surrounding organs in a rat model of apical periodontitis and analyzed the infection route to the gut and distant organs.MethodsWe induced apical periodontitis in rat molars by infecting the dental pulp with F. nucleatum and then took X-ray images and performed histopathologic analyses. Next, we removed the maxilla, gut, heart, liver, and kidney from the rats at 0, 2, 4, and 8 weeks postsurgery and then extracted DNA samples and performed polymerase chain reaction and microbiome analyses using the Illumina MiSeq (Illumina Co, Tokyo, Japan).ResultsThe presence of inflammatory cell infiltration confirmed apical periodontitis from 2–8 weeks. Polymerase chain reaction and microbiome analyses revealed F. nucleatum in the rat gut from 2 weeks and in the kidney from 8 weeks. The rat gut, heart, liver, and kidney exhibited altered bacterial flora, including a marked decrease in Verrucomicrobia and an increase in Proteobacteria after 2 weeks and increases in Bacteroidetes and Firmicutes after 4 weeks.ConclusionsThe onset of F. nucleatum–induced apical periodontitis changed the bacterial flora in the rat gut, heart, liver, and kidney, with a confirmed progressing infection in the large intestines.     

Effect of pretreatments on the metal–ceramic bonding strength of a Pd–Ag alloy

Objectives

The purpose of this study was to evaluate the efficacy of surface treatments on the bonding properties between a metal and ceramic.

Methods

Sixty metal specimens were divided equally into four groups of 15 samples each. These groups received different treatments (Gr1: 250 μm Al₂O₃ + preoxidation; Gr2: 250 μm Al₂O₃ + degassing; Gr3: 120 μm Al₂O₃ + preoxidation; Gr4: 120 μm Al₂O₃ + degassing). Bond strengths were evaluated using a three-point bending test. The results were analyzed using 2-way ANOVA and Tukey's test. Scanning electron microscopy and energy dispersive spectroscopy were used to observe the microscopic features, elemental compositions and distributions, and diffusion in the specimens. Mechanical profiler was used to measure the roughness of metal surface.

Results

The bond strengths of the four groups ranged from 45.00 ± 3.63 MPa to 51.61 ± 5.91 MPa, with significant differences (P < .05). The specimen that received the pretreatment of 250 μm Al₂O₃ air-particle abrasion + degassing had the highest bond strength. Heating under different oxygen partial pressures caused the final Pd–Ag alloys to have varying degrees of internal oxidation and different quantities of metallic nodules. None of the elements in either the ceramic or the Pd–Ag alloy layer diffused into the other layer.

Conclusions

The metal–ceramic specimen subjected to air-particle abrasion with 250 μm Al₂O₃ and degassed before porcelain firing had significantly higher bond strength than specimens treated differently.     

Effect of Shaft Length on the Torsional Resistance of Rotary Nickel–titanium Instruments

IntroductionThis study was conducted to evaluate the effect of file length on the torsional resistance of nickel-titanium rotary files.MethodsForty-five new files with a #25 tip size and variable taper for ProTaper Next (PTN; Dentsply Sirona, York PA), ProTaper Gold (PTG, Dentsply Sirona), and HyFlex CM (HCM; Coltene-Whaledent, Allstetten, Switzerland) were divided into 3 subgroups (n = 15) according to the file length (21, 25, and 31 mm). Torsional tests were performed using a custom-made device (AEndoS; DMJ System, Busan, Korea). The maximum torsional load and distortion angle were measured until file fracture occurred. The toughness was calculated using these data. All data were statistically analyzed using 2-way analysis of variance at a confidence level of 95%. One-way analysis of variance and Duncan post hoc comparison were also conducted to assess the difference among the independent variables, shaft length, and file system.ResultsA statistically significant interaction was observed between the file system and instrument length with respect to the maximum torsional load (P < .05). The 31-mm shaft length of HCM showed higher maximum torsional load than that of the 25- and 21-mm shaft length in the HCM groups (P < .05). Among the instrument systems, PTG showed the significantly highest maximum torsional load followed by PTN and HCM (P < .05). The 31-mm shaft length of PTG showed significantly higher toughness than that of the 21- and 25-mm shaft lengths (P < .05), whereas PTN and HCM did not show any difference in relation to the shaft length.ConclusionsWithin the limitations of this study, the instrument with a longer shaft may have higher maximum torsional load or toughness than that with a shorter shaft.     

Effect of different surface treatments on the composite–composite repair bond strength

The aim of this study was to investigate the effect of different mechanical and adhesive treatments on the bond strength between pre-existing composite and repair composite using two aging times of the composite to be repaired. Standardized cylinders were made of a microhybrid composite (Spectrum TPH) and stored in saline at 37°C for 24 h (n = 140) or 6 months (n = 140). Three types of mechanical roughening were selected: diamond-coated bur followed by phosphoric acid etching, mini sandblaster with 50-μm aluminum oxide powder, and 30-μm silica-coated aluminum oxide powder (CoJet Sand), respectively. Adhesive treatment was performed with the components of a multi-step bonding system (OptiBond FL) or with a one-bottle primer–adhesive (Excite). In the CoJet Sand group, the effect of a silane coupling agent (Monobond-S) was also investigated. The repair composite (Spectrum TPH) was applied into a mould in three layers of 1 mm, each separately light-cured for 40 s. Repair tensile bond strengths were determined after 24-h storage. Mechanical and adhesive treatment had significant effects on repair bond strength (P < 0.001). The age of the pre-existing composite had no significant effect (P = 0.955). With one exception (CoJet Sand/OptiBond FL Adhesive), adhesive treatments significantly increased repair bond strengths to 6-month-old composite when compared to the controls without adhesive. Adhesive treatment of the mechanically roughened composite is essential for achieving acceptable repair bond strengths. The more complicated use of silica-coated particles for sandblasting followed by a silane coupling agent had no advantage over common bonding systems.     

Effect of seating forces on cement–ceramic adhesion in microtensile bond tests

Objectives

The aim of this study was to evaluate the effect of different seating forces during cementation in cement–ceramic microtensile bond strength (μTBS).

Materials and methods

Forty-five blocks (5?×?5?×?4 mm³) of a glass-infiltrated alumina-based ceramic (In-Ceram Alumina) were fabricated according to the manufacturer’s instructions and duplicated in resin composite. Ceramic surfaces were polished, cleaned for 10 min in an ultrasonic bath, silica coated using a laboratory type of air abrasion device, and silanized. Each treated ceramic block was then randomly assigned to five groups (n?=?9) and cemented to a composite block under five seating forces (10 g, 50 g, 100 g, 500 g, and 750 g) using a dual-cured resin cement (Panavia F). The ceramic–cement–composite assemblies were cut under coolant water to obtain bar specimens (1 mm?×?0.8 mm²). The μTBS tests were performed in a universal testing machine (1 mm/min). The mean bond strengths values were statistically analyzed using one-way ANOVA (α?≤?0.05).

Results

Different seating forces resulted in no significant difference in the μTBS results ranging between 13.1?±?4.7 and 18.8?±?2.1 MPa (p?=?0.13) and no significant differences among cement thickness.

Conclusions

Excessive seating forces during cementation seem not to affect the μTBS results.

Clinical relevance

Excessive forces during the seating of single all-ceramic restorations cementation seem to display the same tensile bond strength to the resin cement.     

Effect of different remineralizing agents on the initial carious lesions – A comparative study

ObjectivesThis study aimed to assess and compare the effectiveness of three different remineralizing agents (Tricalcium phosphate paste, Fluoride varnish, and Nano-hydroxyapatite gel) using the DIAGNOdent device.Material and MethodsThe present clinical study was carried out on 90 initial carious lesions detected by ICDAS caries diagnostic criteria and then take the baseline record by DIAGNOdent device. The selected initial carious lesions were randomly classified into three groups according to treatment modalities (30 lesions in each group) according to remineralizing agents: group A (TCP), group B (fluoride varnish) and group C (nano-hydroxyapatite gel). The remineralizing agents were applied for four minutes once weekly for four weeks. At the fifth week, the DIAGNOdent scores of initial carious lesions were recorded to evaluate the effect of remineralizing agents. A paired t-test was used to compare between baseline date and follow up of DIAGNOdent scores. A one-way ANOVA test was used to compare DIAGNOdent scores among the three groups. Post- Hoc Tukey test was used to determine the significant difference between every two groups.ResultsThere were statistically significant differences among the three groups at follow up (p = 0.001). Within each group, there was a significant difference between baseline and follow up scores (p = 0.000 for the three groups). Multiple comparisons between every two groups showed a highly statistically significant difference at follow up records between nano-hydroxyapatite versus TCP and fluoride varnish on pit and fissure caries (p = 0.039 and p = 0.007 respectively) and the nano-hydroxyapatite was the best of them.ConclusionThe present study concluded that the three remineralizing agents were effective in the treatment of initial carious lesion and the most effective remineralizing agent was nano-hydroxyapatite.