Evaluation of Poly(etheretherketone) Post's Mechanical Strength in Comparison with Three Metal-Free Biomaterials: An In Vitro Study.

The thinking about metallic replacement has begun in a global context of reducing metallic alloys' use in odontology. Among the materials proposed for their replacement, poly(etheretherketone) may present interesting properties, especially in removable dentures' frames. The purpose of this study is to evaluate fracture resistance of PEEK posts-and-cores compared to non-metallic CAD/CAM materials and fiber glass posts. Forty extracted maxillary central incisors were prepared to receive posts. Samples were divided into four groups depending on whether they had been reconstructed with LuxaCam® PEEK, Enamic®, Numerys GF® or LuxaPost®. Samples were submitted to an oblique compressive test and results were statistically analyzed with ANOVA and Student's tests (or non-parametric tests depending on the conditions). Glass fiber posts and Numerys GF® reveal a significantly higher fracture resistance than LuxaCam® PEEK and Enamic®. No exclusively dental fracture has been noted for the Enamic group, which significantly distinguishes these samples from the three other groups. In our study, it appears that the conception of posts and cores with hybrid ceramic never conducts to a unique tooth fracture. By weighting the results according to the materials used, our data, obtained for the first time on this type of PEEK block, cannot confirm the possibility of using PEEK for inlay-core conception, excepted for specific cases when the material is considered in a patient presenting allergies or systemic disease contraindicating resin or metal.

Computational fluid dynamics investigations over conventional and modified Savonius wind turbines.

Wind turbines are devices that convert the kinetic energy present in the wind into clean, sustainable, and effectively renewable energy that could be used to generate electricity. A Savonius wind turbine is a drag-based vertical axis wind turbine (VAWT) that is known to have low noise levels and good starting characteristics even at low wind speeds. Its disadvantage lies in its low efficiency or low coefficient of performance. Exploring ways to increase the coefficient of performance, numerical investigations were carried out on different modified Savonius VAWT configurations, having different curvatures, different overlap percentages, added mini blades, and fitted out with extended surfaces. These investigations were computationally executed on Ansys Fluent™ using the sliding mesh technique. Two-dimensional simulations, on a Bach blade curvature with zero overlap as well as a half-circle and a polynomial curvature with overlap, showed that for a wind speed of 5 m/s and a tip speed ratio of 0.8, the half-circle blade curvature having an overlap of 20% performs best, yielding the highest net (average) coefficient of moment, equal to 0.3065. Results also show that the addition of mini blades to this optimal configuration produces a slight improvement in the coefficient of moment. However, the addition of extended surfaces onto the blades caused the minimum coefficient of moment to be a substantial negative value and thus resulting in a much lower value for the turbine's average coefficient of moment.

Effects of Translucency and Thickness of Lithium Disilicate-Reinforced Glass-Ceramic Veneers on the Degree of Conversion of a Purely Light-Curing Bonding Resin: An In Vitro Study.

The objective of this study was to evaluate the variations in the degree of conversion (DC) of a light-curing composite resin when the thickness or the translucency of lithium disilicate-enriched glass-ceramic veneers are modified. IPS e. max® CAD blocks of the MT-A2, LT-A2 and MO1 types were cut to obtain four slices with thicknesses ranging from 0.6 mm to 1 mm. A strictly light-curing composite resin (G-aenial Universal Injectable) was injected in the empty part of a silicone mold so that the veneer could then be inserted under digital pressure to the stop. A 40 s light cure (1400 mW/cm2) was then performed. Resin samples were analyzed using Fourier transform infrared (FTIR) spectroscopy. When the degree of translucency of the ceramic was modified, a decrease in the resin conversion rate was noted, but with a non-significant global p-value (p = 0.062). Interestingly, the degree of conversion of the light-curing composite resin was also modified when the ceramic's thickness increased, especially when it was over 1 mm (DC0.6 > DC0.7 > DC0.8 > DC1; p < 0.0001). This confirms that the degree of conversion of a bonding material is very dependent on the ceramic's thickness. Contradictory data are, however, found in the literature, where there are reports of an absence of a difference between the DC obtained with thicknesses of ceramics of 0.7 and 2 mm.

The use of PEEK as an occlusal splint in a patient with histaminosis: A case report.

Poly-(etheretherketone) (PEEK) began to be used in the field of odontology more than 10 years ago, especially in relation to the creation of removable partial dentures. Here we report the case of a 62 years old woman diagnosed with histamine intolerance (or histaminosis), who presented a very particular set of oral symptoms. She described a certain tingling, burning, and swelling of the mucous membranes. These symptoms seem to be linked with the wearing of a resin occlusal splint which was initially prescribed to compensate for the absence of a meniscus in the left temporomandibular joint of the patient. After a multidisciplinary concertation, it was decided to create a new splint with a resin-free material. For this reason, the production of a PEEK prosthesis was considered. Following the installation of the occlusal splint in the patient, and after clinical adjustments, she described the occlusion positioning as correct and a disappearance of the symptomatology. Mechanically, PEEK seems to have higher mechanical resistance than PMMA. Despite these characteristics, the use of PEEK still presents some limitations, especially concerning the overall aesthetic. Additionally, the prescription of the occlusal splint seems to be limited to patients who need special care. The case presented here thus confirms a new perspective concerning the use of PEEK as an occlusal splint.

Dentin interaction with universal adhesive containing isopropanol solvent studied by solid-state NMR spectroscopy.

OBJECTIVE: This study investigated the chemical and structural changes in the mineral phase and collagen of dentin during application of a mild universal adhesive. Particular attention was paid to the role of isopropanol and changes in water molecules. METHODS: In vitro application of the mild universal adhesive on dentin with two established etching modes (self-etch and etch-and-rinse) was studied using solid state nuclear magnetic resonance spectroscopy. RESULTS: It was evidenced that the etch-and-rinse mode leads to a decrease of the inorganic apatite and a reorganization of the residual mineral phase with a low amount of adhesive phosphate monoesters calcium salt formed, compared to the self-etch mode. In contrast, the adhesive interacts very similarly to the level of dentin collagen in both protocols, with a strong decrease in the amount of the free water molecules induced by the presence of isopropanol as the adhesive solvent, but without significant changes in the initial collagen structure. For both modes, the adhesive acrylates monomers remain mobile and can infiltrate the collagen. SIGNIFICANCE: Understanding the molecular interactions between dentin and adhesive solutions is a major challenge for designing products that lead to the formation of ideal dentin resin hybrid layer. Notably, one point considered essential is the presence of unbound water which, over time, is associated with a hydrolytic degradation of the organic matrix. Isopropanol, as an adhesive solvent, leads to a decrease in the amount of the less stable water molecules while the water molecules strongly attached to the collagen are retained, thus preserving the collagen structure.

From Child to Adulthood, a Multidisciplinary Approach of Multiple Microdontia Associated with Hypodontia: Case Report Relating a 15 Year-Long Management and Follow-Up.

Oral rehabilitation of patients presenting multiple microdontia is a real therapeutic challenge. These alterations in size, often associated with other dental anomalies, have aesthetic and functional repercussions for patients and can lead to significant psycho-social consequences. We report here the case of an 11-year-old patient with bilateral sectorial microdontia and agenesis of teeth numbers 13 and 23. She also presented staturo-ponderal delay and a history of acute coronary syndrome with a lower coronary occlusion of unknown aetiology. At first, additive coronoplasties and an orthodontically retained interim prosthesis answered the aesthetic and functional need during childhood and adolescence. Once she reached adulthood, a multidisciplinary meeting was conducted and a treatment plan was established. The decision was made to rehabilitate the upper arch with a permanent bridge and the lower arch with indirect adhesive restorations. This solution solved the problem of the bilateral lateral infraocclusions and tooth agenesis, restoring both aesthetics and function. This paper presents 15 years of management and treatment of a patient presenting multiple microdontia associated with hypodontia. Both the multidisciplinary approach and coordination between the different medical team members was essential to maintain the existing dentition while preparing, planning, and carrying out a personalized treatment plan once maxillofacial growth was complete.

Step-by-Step Esthetic Rehabilitation with Chairside System.

In modern dentistry, Computer-Aided Design and Manufacturing (CAD/CAM) is a promising technology that allows fabrication of prosthetic restorations through milling procedures. Over years, with the continuous improvement of technology, direct CAD/CAM or "chairside" technology is becoming a widespread approach which offers immediate rehabilitation with long-term rates reported by several studies compared to conventional techniques. All steps are generally carried out in the dental office during the same treatment session. The present paper is about a healthy female patient with a decayed 36 tooth which was restored by ceramic onlay using Planmeca's PlanCAD system. Through the present clinical case, a detailed protocol of chairside technology would be presented from the digital impression to the milling process. It would detail impression steps. It would also highlight especially the virtual design confection of prosthetic restoration using a biogeneric model included in the software. It also illustrated tools which could be used by the dentist to perform the design. Also, some useful tips would be presented in order to perform the confection. On this subject, various studies showed the viability of such technology. To summarize, referring to previous studies, this promising technology allows especially time-saving and patient's comfort compared to the indirect one.

Recent Advances in Cone-beam CT in Oral Medicine.

BACKGROUND: The cone-beam computed tomography (CBCT) technology has continuously evolved since its appearance in oral medicine in the early 2000s. OBJECTIVES: To present recent advances in CBCT in oral medicine: i) selection of recent and consensual evidence-based sources, ii) structured summary of the information based on an iterative framework and iii) compliance with ethical, public health and patient-centered concerns. MAIN FINDINGS: We will focus on technological advances, such as sensors and reconstruction algorithms used to improve the constant quality of the image and dosimetry. CBCT examination is now performed in almost all disciplines of oral medicine: currently, the main clinical disciplines that use CBCT acquisitions are endodontics and oral surgery, with clearly defined indications. Periodontology and ear, nose and throat medicine are more recent fields of application. For a given application and indication, the smallest possible field of view must be used. One of the major challenges in contemporary healthcare is ensuring that technological developments do not take precedence over admitted standards of care. The entire volume should be reviewed in full, with a systematic approach. All findings are noted in the patient's record and explained to the patient, including incidental findings. This presupposes the person reviewing the images is sufficiently trained to interpret such images, inform the patient and organize the clinical pathway, with referrals to other medical or oral medicine specialties as needed. CONCLUSION: A close collaboration between dentists, medical physicists, radiologists, radiographers and engineers is critical for all aspects of CBCT technology.

Incidental Findings in Dental Radiology are Concerning for Family Doctors.

Cone Beam Computerized Tomography (CBCT) is an imaging technology increasingly used in dentistry. Depending on the size of the examination area, visualization of anatomical structures outside the indication area may reveal incidental findings (IF). The aims of this systematic review and meta-analysis were to 1) evaluate the frequency, location and different types of incidental findings (IF) revealed during CBCT examinations; 2) identify potential influencing factors such as gender or age; 3) highlight what the family doctor should know about CBCT and the benefits for medical care. 70 retrospective studies were included. 60% of IF are in the naso-oropharyngeal airway and paranasal sinuses. Carotid calcifications were observed with a mean prevalence of 9% CI95% [2-21]). Meta-regression showed a significant association of this prevalence with age, irrespective of gender. Given the high frequency of IF, with varying severity, the whole medical community is fully involved, and its opinion should be sought to ensure the best possible management for the patients. Physicians may also require CBCT examinations that would have been previously prescribed by a dentist, that may serve to better orientate investigations toward another imaging technique. The family doctor is therefore the dentist's main interlocutor and the main coordinator of the follow-up of IF.

Three-dimensional analysis of bitemarks using an intraoral scanner.

Conservation of the three-dimensional aspect of bitemarks is important to optimize their correct analysis. Bitemarks could be recorded with a surface scanner. In clinical dentistry, optical cameras are used as an alternative to conventional dental impressions. They scan the dental relief for prosthetic design. We propose a three-dimensional bitemark analysis protocol using an intraoral scanner. Eight volunteers bit on different materials: dental wax and hard cheese. Then, bitemarks and dentitions were scanned with the intraoral scanner. The scans obtained were exported into the mesh comparison software, CloudCompare®, which can automatically generate overlays. For this purpose, dentition were aligned and compared with indentations. The meshing and non-meshing areas were easily visualized using a colorimetric scale. This protocol made it possible to exclude incorrect dentitions in about twenty minutes. Moreover, dentitions corresponding to bitemarks all matched. In order to refine this protocol, it must be tested with morphologically close dentitions and on the skin as well.

A contribution of CAD/CAM treatment of a dental trauma in a special care patient.

After a dental trauma, difficulties of communication and the consequences of the complex clinical situation often make regular chairside oral care long and complicated for special needs patients. The aim of this case report is to show how CAD/CAM technology may help in the prosthetic treatment of a clinical situation by keeping the number and duration of clinical sessions to a minimum while enabling a good aesthetic and functional result to be achieved in the long term.

Survival of directly placed ormocer-based restorative materials: A systematic review and meta-analysis of clinical trials.

OBJECTIVES: In-vitro experiments on ormocers (ORganically MOdified CERamics) have provided controversial results. Consequently, the objectives of this meta-analysis were to (1) compare clinical performances of first generation ormocers versus conventional composite restorations, (2) explore the influence of various clinical factors and the impact of the quality of studies on published results. METHODS: The following databases were explored until 2017/01/08: Ovid MEDLINE In-Process, Pubmed, CENTRAL, HTA, DARE, LILACS and Google Scholar. Studies of more than two years with quantitative comparisons between ormocers and control groups were selected. Outcome was the failure of a restoration (need to repair, remove or replace). Multivariate random-effects Poisson's regression was used to obtain a summary estimate. RESULTS: 75% of the 8 included trials concerned Class I/II restorations. Although non-significant, the global failures were higher for ormocers (0.22 [-0.16; 0.61]). For Class I/II restorations, a significantly higher sensitivity was observed for ormocer-based materials compared to other composites (0.75 [0.01; 1.50]). An increase of the number of restorations per patient was associated with higher marginal adaptation failures for ormocers in Class I/II obturations (0.59 [0.11; 1.08]). SIGNIFICANCE: This study did not identify clear advantages of using the first generation of ormocer-based fillings rather than conventional composites. Given the recent development of new, dimethacrylate-diluent-free ormocer matrices, potentially more stable and resistant, new randomized clinical trials should be developed comparing this new family of pure ormocers with current composites.

Efficacy of composite versus ceramic inlays and onlays: study protocol for the CECOIA randomized controlled trial.

BACKGROUND: Dental caries is a common disease and affects many adults worldwide. Inlay or onlay restoration is widely used to treat the resulting tooth substance loss. Two esthetic materials can be used to manufacture an inlay/onlay restoration of the tooth: ceramic or composite. Here, we present the protocol of a multicenter randomized controlled trial (RCT) comparing the clinical efficacy of both materials for tooth restoration. Other objectives are analysis of overall quality, wear, restoration survival and prognosis. METHODS: The CEramic and COmposite Inlays Assessment (CECOIA) trial is an open-label, parallel-group, multicenter RCT involving two hospitals and five private practices. In all, 400 patients will be included. Inclusion criteria are adults who need an inlay/onlay restoration for one tooth (that can be isolated with use of a dental dam and has at least one intact cusp), can tolerate restorative procedures and do not have severe bruxism, periodontal or carious disease or poor oral hygiene. The decayed tissue will be evicted, the cavity will be prepared for receiving an inlay/onlay and the patient will be randomized by use of a centralized web-based interface to receive: 1) a ceramic or 2) composite inlay or onlay. Treatment allocation will be balanced (1:1). The inlay/onlay will be adhesively luted. Follow-up will be for 2 years and may be extended; two independent examiners will perform the evaluations. The primary outcome measure will be the score obtained with use of the consensus instrument of the Fédération Dentaire Internationale (FDI) World Dental Federation. Secondary outcomes include this instrument's items, inlay/onlay wear, overall quality and survival of the inlay/onlay. Data will be analyzed by a statistician blinded to treatments and an adjusted ordinal logistic regression model will be used to compare the efficacy of both materials. DISCUSSION: For clinicians, the CECOIA trial results may help with evidence-based recommendations concerning the choice of materials for inlay/onlay restoration. For patients, the results may lead to improvement in long-term restoration. For researchers, the results may provide ideas for further research concerning inlay/onlay materials and prognosis.This trial is funded by a grant from the French Ministry of Health. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01724827.

Effects of dentine moisture on the permeability of total-etch and one-step self-etch adhesives.

OBJECTIVES: The aim of this study was to compare the technique sensitivity of a one-bottle total-etch adhesive and a self-etch primer adhesive to the moisture condition of the dentine substrate. METHODS: The methods used were hydraulic conductance, light microscopy and scanning electron microscopy. RESULTS: When the moisture conditions of the dentine surface are modified with respect to the standard, the bonded interfaces obtained with the one-bottle total-etch Adper Scotch Bond 1 XT (SB) and the all-in-one self-etch Adper Prompt L-Pop (AP) are morphologically highly perturbed. But, although this study also showed a significant (p<0.01) relationship between increases in permeability of resin-bonded dentine and variations of dentine moisture conditions with SB, a significant relationship was found only for the influence of the over-wet condition with AP. CONCLUSION: Within the limitations of this study, the self-etch primer tested gave a greater reduction in dentine permeability than the one-bottle adhesive, while being more tolerant to handling. Although excess water should be avoided with both these systems, air-drying can be an alternative to wet-bonding with the self-etch primers, thus reducing the sensitivity to technique.

Acrylophosphonic acid reactivity with calcium ions and biological apatite.

OBJECTIVES: Acrylophosphonic acid (H(2)L) was reacted with biological apatite originating from dental enamel powder in order to identify and study the reaction products formed during the use of self-etch monomers. Nuclear magnetic resonance spectroscopy (NMR) showed the formation of brushite and a calcium salt of acrylophosphonic acid. This Ca salt was further synthesized and characterized by NMR, Fourier transform-infrared (FT-IR) and chromatography coupled with potentiometric analysis. The results reveal that calcium ions form a compound with two mono-deprotonated acrylophosphonate anions at physiological pH values. Thus, dissolution of the biological apatite by the acid-etch releases phosphate and calcium ions that combine to form brushite. The remaining dissolved Ca neutralize the acrylophosphonic acid to form an ionic salt of formula Ca(HL)(2). SIGNIFICANCE: The stoichiometry of this calcium salt allows us to conclude that, following a self-etch procedure, dissolved Ca ions participate in the formation of crosslinks in the complex photopolymerized copolymer composite network of the hybrid layer.

Release of aqueous calcium and phosphate from human dental enamel following administration of self-etching adhesives.

Seven self-etching adhesives were studied on an experimental reconstituted human enamel model. The objective was to evaluate the acid dissociation step of the enamel minerals. The self-etching products were applied to the enamel specimens according to the manufacturers' instructions and then rinsed with distilled water. The aqueous calcium and phosphate released were analysed chemically by atomic absorption and ion chromatography, respectively. Results show widely varying concentrations related to pH, acid concentration and calcium binding capacity. All concentrations are less than reference values obtained with orthophosphoric acid. The effectiveness of self-etchants is discussed in terms of their ability to demineralise human enamel and incorporate the released ions in the subsequent HEMA co-polymer composing the hybrid layer.