The Impact of Simulated Bruxism Forces and Surface Aging Treatments on Two Dental Nano-Biocomposites-A Radiographic and Tomographic Analysis.

Background and Objectives: Nowadays, indication of composite materials for various clinical situations has increased significantly. However, in the oral environment, these biomaterials are subjected (abnormal occlusal forces, external bleaching, consumption of carbonated beverages, etc.) to changes in their functional and mechanical behavior when indicated primarily for patients with masticatory habits. The study aimed to recreate in our lab one of the most common situations nowadays-in-office activity of a young patient suffering from specific parafunctional occlusal stress (bruxism) who consumes acidic beverages and is using at-home dental bleaching. Materials and Methods: Sixty standardized class II cavities were restored with two nanohybrid biocomposite materials (Filtek Z550, 3M ESPE, and Evetric, Ivoclar Vivadent); the restored teeth were immersed in sports drinks and carbonated beverages and exposed to an at-home teeth bleaching agent. The samples were subjected to parafunctional mechanical loads using a dual-axis chewing simulator. A grading evaluation system was conducted to assess the defects of the restorations using different examination devices: a CBCT, a high-resolution digital camera, and periapical X-rays. Results: Before mechanical loading, the CBCT analysis revealed substantially fewer interfacial defects between the two resin-based composites (p > 0.05), whereas, after bruxism forces simulation, significantly more defects were identified (p < 0.05). Qualitative examination of the restorations showed more occlusal defects for the Evetric than the other nanohybrid composite. Conclusions: There were different behaviors observed regarding the studied nanocomposites when simulation of parafunctional masticatory forces was associated with aging treatments.

Effects of Acidic Environments on Dental Structures after Bracket Debonding.

Brackets are metallic dental devices that are very often associated with acidic soft drinks such as cola and energy drinks. Acid erosion may affect the bonding between brackets and the enamel surface. The purpose of this study was to investigate the characteristics of brackets' adhesion, in the presence of two different commercially available drinks. Sixty human teeth were divided into six groups and bonded with either resin-modified glass ionomer (RMGIC) or resin composite (CR). A shared bond test (SBS) was evaluated by comparing two control groups with four other categories, in which teeth were immersed in either Coca-ColaTM or Red BullTM energy drink. The debonding between the bracket and enamel was evaluated by SEM. The morphological aspect correlated with SBS results showed the best results for the samples exposed to artificial saliva. The best adhesion resistance to the acid erosion environment was observed in the group of teeth immersed in Red BullTM and with brackets bonded with RMGIC. The debonded structures were also exposed to Coca-ColaTM and Red BullTM to assess, by atomic force microscopy investigation (AFM), the erosive effect on the enamel surface after debonding and after polishing restoration. The results showed a significant increase in surface roughness due to acid erosion. Polishing restoration of the enamel surface significantly reduced the surface roughness that resulted after debonding, and inhibited acid erosion. The roughness values obtained from polished samples after exposure to Coca-ColaTM and Red BullTM were significantly lower in that case than for the debonded structures. Statistical results evaluating roughness showed that Red BullTM has a more erosive effect than Coca-Cola™. This result is supported by the large contact surface that resulted after debonding. In conclusion, the prolonged exposure of the brackets to acidic drinks affected the bonding strength due to erosion propagation into both the enamel-adhesive interface and the bonding layer. The best resistance to acid erosion was obtained by RMGIC.

A Systematic Analysis of the Available Human Clinical Studies of Dental Implant Failure in Patients with Inflammatory Bowel Disease.

Background and objectives: The aim was to evaluate the current literature on the influence of inflammatory bowel disease (ulcerative colitis/Crohn's disease) in dental implant osseointegration in human clinical studies. Materials and methods: This review was conducted under the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. PubMed, Scopus, and Web of Science databases were electronic screened to find relevant articles published until October 2021. The inclusion criteria consisted of human clinical studies that reported the use of dental implant in patients diagnosed with inflammatory bowel disease. Risk of bias was assessed according to The Strengthening the Reporting of Observational studies in Epidemiology criteria. Results: A total of 786 studies were identified from databases. Of these, six studies were included in the review and reported the use of implants in patients with Crohn's disease. No articles were available for ulcerative colitis. Included articles indicated that Crohn's disease may determine early and late implant failure. Besides Crohn's disease, several patients presented associated risk factors and systemic disease that determined implant failure. Conclusions: The presence of clinical studies on the influence of IBD in implant therapy is low. When recommending an implant therapy to IBD patients, the multidisciplinary team should be aware of side effects and a close collaboration between members of this team is necessary. More data are needed to sustain the effect of IBD on implant therapy.

The Use of Laser Energy for Etching Enamel Surfaces in Dentistry-A Scoping Review.

BACKGROUND: In dental practice, different situations require etching the enamel layer. Acid etching, the present golden standard, may be replaced by other methods, such as laser etching. The main focus of our scoping review is to assess the existent literature regarding the effectiveness of different types of lasers, to identify the main aspects studied so far, and to understand where new search strategies are needed. METHODS: The search was conducted in several databases focusing on the laser etching of human definitive enamel. We included English language articles published between January 2000 and December 2021. RESULTS: The 34 articles reviewed showed that hard lasers, Er:YAG, Er,Cr:YAG, may represent an alternative etching method on enamel surfaces. They create a fractured, irregular surface and open dentin tubules, highly suitable for adhesion but with a lower risk of cavity formation. Nd:YAG, CO2, and Diode lasers do not help in creating sufficient shear bond strength. There is, however, evidence suggesting that microcracks in the enamel layer may appear after thermomechanical ablation using laser energy. CONCLUSIONS: While the use of acid etching is still successfully used for enamel conditioning, some researchers have emphasized the role played by saliva in the enamel-remineralization process a few days after the procedure. In this context, laser energy can be used, especially for bonding ceramic brackets in the case of orthodontic treatments. However, as thermomechanical ablation can generate microcracks, further research is required in order to establish clear findings concerning the use of laser energy on enamel etching.

Bruxism's Implications on Fixed Orthodontic Retainer Adhesion.

BACKGROUND: Fixed retainers assist in maintaining the outcomes of orthodontic treatment. Fixed retention may be affected by bruxism. OBJECTIVE: Evaluate two adhesives (an ormocer and a flowable composite) used for fixed orthodontic retention in simulated bruxism settings, compared to regular mastication, using a dual axis chewing simulator. METHODS: Eighty human teeth were used. Periodontal tissues were simulated and exposed to 120,000 mechanical cycles, corresponding to 6 months of clinical service. Each set of two teeth was supplied with a pre-shaped, fixed, multi-braided, stainless steel wire retainer, in 1.5 cm portions, to establish passive contact with the lingual surface of the teeth. The Adhesive Remnant Index (ARI) was used to evaluate the shear bond strength. A stereomicroscope was used to assess the micro-infiltration. RESULTS: There was no significant difference in the mean value of micro-infiltration between adhesives in the mastication group but in the bruxism group. During testing, one composite sample (ARI score 1) was broken in the mastication group, while three ormocer samples (ARI score 2) and one composite sample (ARI score 1) were broken in the bruxism group. CONCLUSIONS: The mean value for micro-infiltration in composite (0.31) was more than double that in ormocer (0.13).

Photodynamic Therapy with Natural Photosensitizers in the Management of Periodontal Disease Induced in Rats.

This study aims to investigate the effect of new natural photosensitizers (PS) (based on oregano essential oil, curcuma extract, and arnica oil) through in vitro cytotoxicity and biological tests in rat-induced periodontal disease, treated with photodynamic therapy (aPDT). The cytotoxicity of PS was performed on human dental pulp mesenchymal stem cells (dMSCs) and human keratinocyte (HaCaT) cell lines. Periodontal disease was induced by ligation of the first mandibular molar of 25 rats, which were divided into 5 groups: control group, periodontitis group, Curcuma and aPDT-treated group, oregano and aPDT-treated group, and aPDT group. The animals were euthanized after 4 weeks of study. Computed tomography imaging has been used to evaluate alveolar bone loss. Hematological and histological evaluation showed a greater magnitude of the inflammatory response and severe destruction of the periodontal ligaments in the untreated group.. For the group with the induced periodontitis and treated with natural photosensitizers, the aPDT improved the results; this therapy could be an important adjuvant treatment. The obtained results of these preliminary studies encourage us to continue the research of periodontitis treated with natural photosensitizers activated by photodynamic therapy.

Orthodontic Attachment Adhesion to Ceramic Surfaces.

Ceramic materials are constantly evolving, achieving good functionality and aesthetics. Bonding to ceramics may be difficult because of high toxicity procedures and risk of surface damage. The review aims to answer several research questions: Is there a golden standard for bonding to ceramic? Are there adhesives or types of photopolymerization lamps that produce a higher bond strength on certain types of ceramics rather than others? Articles focusing on the bonding process of orthodontic attachments to ceramic surfaces searched in Pubmed, Medline and Embase, published between 1990 and 2018 were revised. Exclusions concerned bonding to non-ceramic surfaces, bonding to ceramic surfaces that are not destined for orthodontics or laser usage. Forty-nine articles that matched the inclusion criteria were researched. The following categories of original research articles were compared and discussed: metallic brackets bonding to ceramic surfaces, ceramic brackets to ceramic surfaces, bonding to new types of ceramics, such as zirconia, lithium disilicate, different photopolymerisation devices used on bonding to ceramics. Some types of adhesive may achieve minimal bond strength (6-8 MPa) even on glazed ceramic. Ceramic surface preparation may be done by sandblasting or hydrofluoric acid (60s application and 9.6%) with generally similar results. Studies rarely show any statistical difference and there are reduced number of samples in most studies. Ceramic brackets show better adhesion to ceramic surfaces and the same bonding protocol is advised. A higher bond strength may lead to ceramic surface. Few studies focus on newer types of ceramics; additional research is necessary. There is no clear evidence that a certain type of photopolymerization device produces higher shear bond strength values.

Dental Sealant Composition-Retention Assessment in Young Permanent Molars.

Tooth decay in children and adolescents remains a public health problem, despite prophylaxis and preventive measures being largely available. The aim of our study was to evaluate the clinical behavior of four dental sealants, related to first permanent molar topography and patient age (when sealant was applied for the first time). We assessed, by means of visual inspection and palpation with a dental probe, a group of 200 children, enrolled corresponding to school age-grade (mean age of 7 years at baseline) and randomly divided according to the material used as dental sealant (Admira seal©, Embrace Wet Bond©, Fotoseal©, GC Fuji Triaje©) in 4 groups (n = 50). Sealant clinical evaluation was made at 6-, 12-, 18-month intervals for dental material retention assessment. At 6 months, the sealant detached the most from 3.6 molars, and the material used was Fotoseal© (27.6%). At 12 months, Fotoseal© (48.3%) and GC Fuji Triaje© (41.4%) from 3.6 molars express detachment. At 18 months, 4.6. molars sealed with Admira Seal© (25.7%) and Embrace Wet Bond© (28.6%) lost the sealant. We noticed less detachment in maxillary molars and if sealant was applied around 7 years of age. In conclusion, sealant application on first permanent molars must be encouraged and practitioners can choose between various materials available.

Assessment and Characterization of Some New Photosensitizers for Antimicrobial Photodynamic Therapy (aPDT).

The novelty of this study consists on the formulation and evaluation of five complex experimental natural photosensitizers (PS): gel with oregano essential oil (O), gel with methylene blue (AM), gel with a mixture of essential oils (Thieves-H), gel with arnica oil and curcuma extract (CU) and gel with frankincense essential oil (T), used as photosensitizing agents (PS) in antimicrobial photodynamic therapy (aPDT) in the control of microbial biofilm in oral cavity. The experimental PS were characterized by gas chromatography-mass spectrometry (GC-MS), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy, cytotoxicity assay, antimicrobial effect and scanning electron microscopy (SEM). The IR spectra of the experimental PS with essential oils exhibit absorption bands due to the presence of water and glycerol in high quantities. The studied compounds had a reduced cytotoxic effect on cell cultures. The lowest cytotoxic effect was observed in experimental PS with oregano essential oil and methylene blue PS. Essential oils with proven antibacterial capabilities used in experimental PS confer antibacterial activity to the gels in which they are incorporated, an activity that may be more efficient use of a PDT therapy. Single bacteria were detected mainly by SEM after 12 h, while aggregate bacteria and micro colonies dominated the samples at 48 h.

Toothpaste Composition Effect on Enamel Chromatic and Morphological Characteristics: In Vitro Analysis.

The aim of this in vitro study was to assess the effect of toothpastes, with different compositions, on optical and morphological features of sound and demineralized enamel. We selected twenty-five teeth, recently extracted for orthodontic purposes, for this in vitro study. The teeth were caries free, without stains, fissures, filling or hypoplasia observed at inspection under standard conditions. Teeth were brushed (for 2-3 min, twice a day, for 21 days), with five different toothpastes (four commercially available and an experimental one) containing fluoride and hydroxyapatite. After that, teeth were demineralized with 37% orthophosforic acid (Ultra Etch®, Ultradent Products Inc., South Jordan, UT, USA) for 60 s. We repeated the brushing protocol for another 21 days on demineralized enamel. Enamel vestibular surfaces were examined using a spectrophotometer (Vita EasyShade -Vita Zahnfabrik, Bad Sackingen, Germany) and a Scanning Electron Microscope (Inspect S®, FEI Company, Hillsboro, OR, USA). Differences were statistically significant for colour parameters L* and ΔE*. SEM evaluation reveals demineralized enamel mineral gain after brushing with selected toothpastes. Toothpastes with specific ingredients can represent a balance between aesthetic and mineralization, and an oral hygiene correct algorithm is able to preserve enamel characteristics during ortodontic treatement with fixed appliances.

Antibacterial and antifungal activity of endodontic intracanal medications.

BACKGROUND AND AIMS: The sterilization of the entire root canal system represents the main goal of every endodontist, given the fact that the control of the microbial flora is the key point of every root canal treatment. The diversity of microorganisms found inside the root canal and also the resistance of some bacterial species to intracanal medications led to a continuous development of new endodontic products. The present study focuses on the comparison of the antibacterial and antifungal properties of different endodontic products, two commercially available, one experimental plant based extract, and two control substances. METHODS: The disc diffusion assay was used to determine the antibacterial and antifungal properties of chlorhexidine, calcium hydroxide, a mix extract between Arctium lappa root powder and Aloe barbadensis Miller gel, Amoxicillin with clavulanic acid and Fluconazole (as control substances). Two of the most common microorganisms found in endodontic infections were chosen: Enterococcus faecalis (ATCC 29212) and Candida albicans ATCC(10231). RESULTS: All tested substances showed inhibition zones around the discs, for Enterococcus faecalis and Candida albicans, including the experimental mix extract of Arctium lappa root powder with Aloe vera gel. CONCLUSION: The experimental mix extract of Arctium lappa root powder and Aloe vera gel is able to inhibit very resistant microorganisms, like Enterococcus faecalis and Candida albicans.