Periodontal health plays an important role in the longevity of prosthodontic restorations. The issues of comparative assessment of prosthetic constructions are complicated and not fully understood. The aim of this article is to review and present the current knowledge regarding the various technical, clinical, and molecular aspects of different prosthetic biomaterials and highlight the interactions between periodontal health and prosthetic restorations. Articles on periodontal health and fixed dental prostheses were searched using the keywords “zirconium”, “CAD/CAM”, “dental ceramics”, “metal–ceramics”, “margin fit”, “crown”, “fixed dental prostheses”, “periodontium”, and “margin gap” in PubMed/Medline, Scopus, Google Scholar, and Science Direct. Further search criteria included being published in English, and between January 1981 and September 2021. Then, relevant articles were selected, included, and critically analyzed in this review. The margin of discrepancy results in the enhanced accumulation of dental biofilm, microleakage, hypersensitivity, margin discoloration, increased gingival crevicular fluid flow (GCF), recurrent caries, pulp infection and, lastly, periodontal lesion and bone loss, which can lead to the failure of prosthetic treatment. Before starting prosthetic treatment, the condition of the periodontal tissues should be assessed for their oral hygiene status, and gingival and periodontal conditions. Zirconium-based restorations made from computer-aided design and computer-aided manufacturing (CAD/CAM) technology provide better results, in terms of marginal fit, inflammation reduction, maintenance, and the restoration of periodontal health and oral hygiene, compared to constructions made by conventional methods, and from other alloys. Compared to subgingival margins, supragingival margins offer better oral hygiene, which can be maintained and does not lead to secondary caries or periodontal disease.

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Fixed Prosthetic Restorations and Periodontal Health: A Narrative Review

Recently, polyetheretherketone (PEEK) has been introduced to the dental market as a high-performance and chemically inert biomaterial. This study aimed to compare the wear resistance, abrasiveness, color stability, and displacement resistance of zirconia and PEEK milled crowns. An ideal tooth preparation of a first maxillary molar was done and scanned by an intraoral scanner to make a digital model. Then, the prosthetic crown was digitally designed on the CAD software, and the STL file was milled in zirconia (CaroZiir S, Carol Zircolite Pvt. Ltd., Gujarat, India) and PEEK (BioHpp, Bredent GmbH, Senden, Germany) crowns using five-axis CNC milling machines. The wear resistance, color stability, and displacement resistance of the milled monolithic zirconia with unfilled PEEK crowns using a chewing simulator with thermocyclic aging (120,000 cycles) were compared. The antagonist wear, material wear, color stability, and displacement were evaluated and compared among the groups using the Wilcoxon-Mann-Whitney U-test. Zirconia was shown to be three times more abrasive than PEEK (p value < 0.05). Zirconia had twice the wear resistance of PEEK (p value < 0.05). Zirconia was more color stable than PEEK (p value < 0.05). PEEK had more displacement resistance than zirconia (p value < 0.05). PEEK offers minimal abrasion, better stress modulation through plastic deformation, and good color stability, which make it a promising alternative to zirconia crown.

Wear Resistance, Color Stability and Displacement Resistance of Milled PEEK Crowns Compared to Zirconia Crowns under Stimulated Chewing and High-Performance Aging.

Antibiotic resistance rate is rising worldwide. Silver nanoparticles (AgNPs) are potent for fighting antimicrobial resistance (AMR), independently or synergistically. The purpose of this study was to prepare AgNPs using wild ginger extracts and to evaluate the antibacterial efficacy of these AgNPs against multidrug-resistant (MDR) Staphylococcus aureus, Streptococcus mutans, and Enterococcus faecalis. AgNPs were synthesized using wild ginger extracts at room temperature through different parameters for optimization, i.e., pH and variable molar concentration. Synthesis of AgNPs was confirmed by UV/visible spectroscopy and further characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy analysis (EDXA), and Fourier-transform infrared spectroscopy (FTIR). Disc and agar well diffusion techniques were utilized to determine the in vitro antibacterial activity of plant extracts and AgNPs. The surface plasmon resonance peaks in absorption spectra for silver suspension showed the absorption maxima in the range of 400–420 nm. Functional biomolecules such as N–H, C–H, O–H, C–O, and C–O–C were present in Zingiber zerumbet (Z. zerumbet) (aqueous and organic extracts) responsible for the AgNP formation characterized by FTIR. The crystalline structure of ZZAE-AgCl-NPs and ZZEE-AgCl-NPs was displayed in the XRD analysis. SEM analysis revealed the surface morphology. The EDXA analysis also confirmed the element of silver. It was revealed that AgNPs were seemingly spherical in morphology. The biosynthesized AgNPs exhibited complete antibacterial activity against the tested MDR bacterial strains. This study indicates that AgNPs of wild ginger extracts exhibit potent antibacterial activity against MDR bacterial strains.

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Synthesis of Silver Nanoparticles from Extracts of Wild Ginger (Zingiber zerumbet) with Antibacterial Activity against Selective Multidrug Resistant Oral Bacteria

Tooth root resorption is multifactorial, leading to progressive destruction and eventual loss of tooth root dentin and cement. There are internal and external types of root resorption, each having its variety. The etiology and pathogenesis of tooth root resorption are poorly understood, and the most significant etiological factors are trauma, pulpal infection, tooth bleaching, and orthodontic treatment. Tooth root resorption is primarily asymptomatic; thus, it is revealed accidentally by radiographic examination. Progressive clinical manifestations are pain, tooth discoloration, tooth mobility, and other conditions. Awareness of the causes and risk factors allowing tooth root resorption, and regular radiographic examination, in case of necessity, make it possible to reveal resorption at an early stage and to prevent its further development. Thus, the aim of this study is to present etiopathogenesis, a clinical course, and diagnostic peculiarities of internal and external types of tooth root resorption, enabling practicing dentists to timely diagnose root resorption and take appropriate measures to avoid further complications. Within the limitation of this review, even though the etiopathogenesis of tooth root resorption is yet not fully understood, it is suggested that the etiological factors fall into two groups (endogenic and exogenic) to enhance further understanding of the possible causes and mechanisms of root resorption and allow practitioners to monitor high-risk patients and make timely diagnoses. Moreover, radiographic examination and CBCT are indispensable for the diagnosis of root resorption.

https://journals.sagepub.com/doi/pdf/10.1177/00368504221109217

Tooth root resorption: A review

Objective To evaluate the marginal adaptation of computer-aided designing and computer-aided machining (CAD/CAM) fabricated cobalt-chromium and zirconium-oxide-based ceramic crowns compared to those produced by a conventional method. Material and Methods The study consists of three groups; 45 crowns fabricated from cobalt-chromium (CAD-CoCr) and 45 crowns manufactured from zirconium CAD/CAM technology (CAD-Z), and 45 control (C) which consists of conventional metal-ceramic crowns. The marginal discrepancies in vertical dimensions were assessed utilizing a microscope in four surfaces (mesial, distal, vestibular, and oral) for each crown. On completion of the microscopic evaluation, multivariate analysis of variance (MANOVA) was used to study the difference in the four surfaces, considered altogether. Two-way ANOVA revealed the effect of three systems used for gap measurements of each landmark. The differences observed were considered significant at p<0.05. Results There were no differences in the four surfaces revealed by АNOVА in the three groups when considered altogether. Two-way ANOVA of each surface discovered no differences among all groups as well. Conclusion The CAD/CAM crowns revealed a comparable and satisfactory marginal adaptation compared to conventional metal-ceramic crowns. 

In Vitro Microscopic Evaluation of Metal- And Zirconium-Oxide-Based Crowns’ Marginal Fit

The present in vivo study determined the microbiological counts of the gingival crevicular fluid (GCF) among patients with fixed dental prostheses fabricated using three different techniques. A total of 129 subjects were divided into three study groups: first, cobalt-chrome-based, metal-ceramic prostheses fabricated by the conventional method (MC, n = 35); the second group consisted of cobalt-chrome-based, metal-ceramic prostheses fabricated by the computer-aided design and computer-aided manufacturing (CAD/CAM) technique (CC-MC, n = 35); the third group comprised zirconia-based ceramic prostheses fabricated using the CAD/CAM technique (CC-Zr, n = 35). The control consisted of 24 patients using prostheses fabricated with either MC, CC-MC, or CC-Zr. The GCF was obtained from the subjects before treatment, and 6 and 12 months after the prosthetic treatment. Bacteriological and bacterioscopic analysis of the GCF was performed to analyze the patients’ GCF. The data were analyzed using SPSS V20 (IBM Company, Chicago, IL, USA). The number of microorganisms of the gingival crevicular fluid in all groups at 12 months of prosthetic treatment reduced dramatically compared with the data obtained before prosthetic treatment. Inflammatory processes in the periodontium occurred slowly in the case of zirconium oxide-based ceramic constructions due to their biocompatibility with the mucous membranes and tissues of the oral cavity as well as a reduced risk of dental biofilm formation. This should be considered by dentists and prosthodontists when choosing restoration materials for subjects with periodontal pathology.

https://www.mdpi.com/1422-0067/22/11/5463/pdf

Bacteriological Evaluation of Gingival Crevicular Fluid in Teeth Restored Using Fixed Dental Prostheses: An In Vivo Study

Despite the large number of studies on the effect of braces on teeth, there is no information on the dynamics of the state of the ultrastructure of the hard tissues of teeth during orthodontic treatment. The purpose of this study is to examine the state of the hard tissues of the teeth and carry out preventive measures to reduce the risk of complications in the process of orthodontic treatment using a non-removable device. Methods: For the in vitro study, 68 teeth were randomly divided into group A—no prophylactic treatment, and group B—treated with the fluorine varnish Tiefenfluorid. After 35 days, all the teeth were prepared for microscopic examination. The clinical study included 59 patients aged 12–17 years with orthodontic brackets. The split-mouth technique was used. The areas around the bracket of one-half of the oral cavity were treated with Tiefenfluorid every 6 months during the entire treatment period. The teeth of the second half of the oral cavity served as the control group. The data were processed in the SPSS19 package. Results: In vitro and clinical study results showed a statistically significant difference between the prophylactic and control groups of teeth in favor of the prophylactic group, where the statistical significance was p ≤ 0.01.

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Morphological Characteristics and Prevention of Tooth Enamel Demineralization during Orthodontic Treatment with Non-Removable Appliances

BACKGROUND: Due to Coronavirus disease, several body systems are involved, and, in the most severe cases, there may be a multiorgan disfunction. The general symptoms can be associated with lesions of the oral cavity. Among these the most reported are ulcerative lesions, together with vesicles and blisters, petechiae, and erythema multiforme-like lesions, aphthous-like lesions, herpetiform lesions and they typically appear at the same time as general symptoms or within one week. The aim of this study was to describe oral lesions observed in 41 Armenian patients with SARS-CoV-2 infection. METHODS: During the period of April 2020-January 2021, 43 patients aged 25 to 51 years positive for COVID-19 test were referred for a full oral mouth examination and diagnosis at Nord KS dental clinic. RESULTS: Of the 18 patients who were already diagnosed with SARS-CoV-2 infection at the time of the visit, 66.6% presented ulcerative lesions;in this group also Candida Albicans infection and lichenoid lesion were diagnosticated. 29 patients were suspected to be positive for COVID-19 and 23 tested positive. In this group of patient periodontal altera-tions relatable to hyperemia, gingival cyanosis and vascular dilation were the most frequently encountered manifesta-tions.CONCLUSIONS: Our study shows how the type of oral lesions during COVID-19 can be related to a determinate phase of the clinical progression: in the first stage of disease oral lesions could be an early sign of infection and during the full-blown phase of this disease they could be clinical manifestation of vasculitic and thrombotic phenomena responsible of COVID-19 complications. The role played by the oral examination in patients with COVID-19 is important in order to raise the suspicion of infection early and to monitor and improve the state of oral health and painful symptoms, in the event of the appearance of more disabling lesions.

Clinical manifestations of oral mucosa lesions in patients with SARS-CoV-2 infection

Oral lichen planus is a chronic, mucocutaneous condition with an unidentified etiology. Women between the ages of 30 and 60 are most affected. The incidence rate for the entire population is 1-2%. Bilateral lesions are typically whitish, sometimes ulcerated. The importance of this condition is related to the frequency of occurrence, the clinical resemblance to other diseases of the mucosa, sometimes with persistent pain and the possible relationship with squamous cell carcinoma. There are several hypotheses regarding the etiology of these diseases, they include: the genetic factor, infectious, psychogenic and autoimmune. The diagnosis of oral plan lichen is made on the basis of clinical and morphopathological examination where information on changes in tissue and cells is obtained.

Mikayel Manrikyan

Papers

Bacteriological Evaluation of Gingival Crevicular Fluid in Teeth Restored Using Fixed Dental Prostheses: An In Vivo Study

Morphological Characteristics and Prevention of Tooth Enamel Demineralization during Orthodontic Treatment with Non-Removable Appliances

Clinical manifestations of oral mucosa lesions in patients with SARS-CoV-2 infection

Clinical and morphopathological aspects af oral lichen planus