Description and Durability of the Various Indirect Restoration Techniques in Molar-Incisor Hypomineralisation: A Systematic Review

Molar-incisor hypomineralisation (MIH) is a qualitative defect of the enamel structure. Indirect restorations may represent the most suitable therapeutic solutions for patients presenting MIH with tooth restorative procedures. This systematic review aims to determine the feasibility of indirect restorations.

MATERIALS AND METHODS

A systematic review has been performed and is reported following the PRISMA guidelines. It was performed on three databases (PubMed, Science Direct, and Google Scholar). Ten articles were included.

RESULTS

Only two articles reported the use of CAD/CAM technologies, whereas the other eight preferred conventional registration and handmade stratification for ceramics. All indirect bonded restorations made of composite resins or ceramics had significant success rates. A temporary material was placed in most of the articles. There was no clear consensus for tissue conditioning before bonding. Depending on the authors and the articles, the follow-up period extended from 2 months to 6 years.

CONCLUSIONS

The survival rate and the non-invasive procedures of indirect restorations are two main arguments that can help dental practitioners in daily practice. Development of CAD/ CAM technologies adds new perspectives in the registration, the design and production. However, more clinical trials are needed to confirm the conclusions.

Impact of Finishing and Polishing Procedures on CAD/CAM In Vitro Milled Ceramics Surfaces: A Systematic Review

INTRODUCTION AND OBJECTIVES

CAD/CAM prostheses may be produced in prosthetic laboratories or directly by practitioners. Quality of ceramic polishing procedures is a controversial topic and it would be interesting for practitioners working with CAD/CAM devices to determine which method is the most efficient regarding finishing and polishing. This systematic review aims to evaluate the impact of different finishing and polishing procedures on the surface of milled ceramics.

MATERIALS AND METHODS

A precise request was launched on the PubMed database. Studies included if they met the criteria of a specifically prepared PICO search. A first selection was performed by analysing titles and abstracts: the articles presenting a study conducted on non-CAD/CAM milled ceramics and research not containing comparisons of finishing procedures were not included. Roughness was evaluated in 15 articles. Nine papers recommended mechanical polishing over glazing regardless of the type of ceramic used. However, no significant differences were detected between the surface roughness of glazed and polished ceramics in nine other publications.

CONCLUSIONS

there is no scientific evidence demonstrating the superiority of hand polishing over glazing on CAD/CAM-milled ceramics.

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.

Decomposition mechanism of hydroxychloroquine in aqueous solution by gamma irradiation

One of the advanced oxidative processes is gamma irradiation, an efficient technique for removing pesticides and pharmaceutical products. Radiolytic degradation leads to free radical’s formation, which facilitates molecular lesion and breaks the chemical bonds. The use of pharmaceutical compounds, such as hydroxychloroquine (HCQ), is increasing nowadays due to the Covid 19 pandemic situation. This study focused on gamma radiation-induced degradation of HCQ in aqueous solution. The degradation was monitored by High-Performance Liquid Chromatography (HPLC) using an Eclipse XDB-C18 column (150 × 3.0 mm, 3.5 µm) and a mobile phase composed of 94% water (phosphate buffer at pH = 3.6) and 6% acetonitrile, with a DAD detection at λ = 343 nm. The effect of different gamma radiation doses (from 0.05 to 3 kGy) was investigated. Chromatographic analysis shows that 1 kGy dose is effective to degrade completely HCQ at 20 ppm and following a first-pseudo-kinetic order with a dose constant corresponding to 4.2 kGy⁻¹. A comparison was done between gamma degradation and other methods. LC-QToF-MS/MS identified the intermediate products, and their kinetic constants were determined. A mechanism pathway was proposed for HCQ degradation under gamma irradiation.

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.

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.

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

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.

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.

Idiopathic subclinical enteropathy in southern Iran

A study of 100 normal subjects from villages in southern Iran revealed that almost one third of this population had one (or more) absorptive or morphological abnormality of the small-bowel mucosa. The finding of morphologically normal bowel mucosa in stillborn fetuses and in newborns who died within two weeks of birth was consistent with the possibility that the abnormalities noted in the village population were postnatally acquired. Finally, speculations are offered regarding the relationship of idiopathic enteropathy and "immunoproliferative small intestinal disease," which is often seen in the region.

T and B lymphocytes in alpha-chain disease

The patients studied were diagnosed as suffering from alpha-chain disease by their clinicopathological features, malabsorption findings, X-ray, and presence of abnormal alpha-chain protein in their serum. The objective of the study was to determine any possible defect of the immune system in such patients. The rosette technique and surface immunofluorescence were used to enumerate the circulating T and B lymphocytes in these patients. They were also skin-tested with tuberculin and given sensitizing doses of dinitrochlorobenzene. Their serum immunoglobulins were also quantitated. It was found that the proportion of circulating B lymphocytes was much higher than normal, whereas that of T lymphocytes was lower than normal. Furthermore, they could not be sensitized to DNCB and their skin test to tuberculin was negative. It was concluded that the disease was a B-cell disease of IgA type, associated with low level of cellular immunity.

Alpha heavy-chain disease in southern Iran

A prospective study of 32 patients with primary upper small intestinal lymphoma in our region revealed 10 cases of alpha heavy-chain disease. Patients were mostly in the second and third decades of life and males predominated. Weight loss, diarrhea, and abdominal pain were the most common complaints and clubbing the most frequent physical findings. Laboratory tests revealed a malabsorption pattern on intestinal x-rays, and malabsorption of xylose, fat, and vitamin B12 was frequently noted. Dense plasmacytic infiltrate of the lamina propria of small bowel was the most frequent pathologic finding while true neoplasm of the lymphoid system (ie, immunoblastic sarcoma) was encountered in 20% of the cases.

Colorectal polyps and carcinoma in Southern Iran

A study was made of the prevalence of colorectal polyps (excluding juvenile polyps, familial polyposis coli and villous adenomas) and the minimum frequency of colorectal carcinoma in Southern Iran. A total of 801 large intestines from necropsies performed on individuals 20 years or older was examined with or without magnifying lens for presence of polyps. Our prevalence rate was then compared with those reported on postmortem material from the USA, Australia, South Africa (Bantus), Colombia, and Hawaii (Japanese immigrants). Our surgical pathology files were reviewed for colorectal polyps over a 22-year period (1952-1973). Colorectal carcinomas diagnosed in the Department of Pathology were reviewed over 11 years (1963-1973) and the minimum frequency rates compared with corresponding age- and sex-specific incidence rates from Connecticut, USA. The data indicate 1) a very low prevalence rate for colorectal polyps as well as carcinoma in our region and 2) a rather striking predominance of right-sided colonic carcinoma.

Alpha-chain disease and its association with intestinal lymphoma

Twenty-seven intestinal lymphoma patients were studied. Abnormal alpha-chain immunoglobulin was detected in the sera of seven of these patients. The alpha-chain disease patients were from the rural areas of Southern Iran. They were of low socio-economic status and their age ranged from 15-44 years. Predominant clinical features were malabsorption, diarrhoea , abdominal pain, vomiting, and weight loss. Infiltration of mucosa of the small intestine with plasma cells and also distortion and flattening of the villi were common histopathologic characteristics of these patients. Involvement of mesenteric lymph nodes with infiltration of tumour cells was observed in a number of cases. Protein studies revealed no significant differences between the serum immunoglobulin levels of these patients and normal values. Immunoelectrophoresis using monospecific antiserum against H-chain of human IgA demonstrated the abnormal precipitin band of alpha-chain disease protein.

Primary upper small-intestinal lymphomal A report of 40 cases fron Iran

Primary upper small-intestinal lymphoma (PUSIL) has now been recognized as a distinct clinical entity with a distinct geographic distribution. Herewith are presented 40 cases of PUSIL seen at Pahlavi University Hospitals in Southern Iran. The investigation reveals the lymphoma to be predominantly a disease of those under 30 and males; the major complaints and physical findings point to an intraabdominal disease. An exception has been clubbing and osteoarthropathy. Special features of PUSIL include: (1) protein loss into the gastrointestinal tract leading to hypoalbuminemia and edema; (2) an antibiotic-responsive diarrhea and steatorrhea; and (3) an associated abnormal heavy-chain protein. The study further stresses the importance of peroral small-intestinal biopsy and the pathologic features of this condition.

Idiopathic enteropathy: an evaluation in rural Iran with an appraisal of nutrient loss

Idiopathic enteropathy in the rural population of Iran was investigated through evaluation of 100 randomly selected apparently normal subjects. The evaluation included quantitation of the nutrient loss, presence of malabsorption, and small intestinal morphological abnormalities. The results show that: 1) there was no significant loss of major nutrients, 2) severe malabsorption was not present, 3) an enteropathy of unknown etiology was found in nearly one-third of the subjects, and 4) abnormalities in morphology did not necessarily mean presence of malabsorption.

Primary lymphoma of the upper small intestine

Seven patients with primary lymphoma involving the upper small intestine and presenting with diarrhoea, non-specific abdominal pain, and clubbing are reported. The disease appears to be more prevalent in young women, and clinical and radiological findings can provide an excellent preliminary diagnosis which is usually confirmed by peroral biopsy of the small intestine. This type of lymphoma is found to be clinically distinguishable both from the primary intestinal lymphomas reported from western countries and also from gastrointestinal involvement as part of a more systemic disease. It appears to be prevalent in the Middle East, and because of clear clinical, radiological, and histological features, it can be singled out from other primary intestinal lymphomas and considered as a distinct clinical entity.

Osteomyelitis complicating regional enteritis

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