Overall Review on Recent Applications of Raman Spectroscopy Technique in Dentistry

Funding Information: Acknowledgements are due to S. Pessanha and V. Vassilenko, from NOVA School of Science and Technology, for the general supervision, guidance, and systematic remarks and comments. Publisher Copyright: © 2023 by the author.The present paper reviews the applications of Raman spectroscopy in dentistry in the past two decades. This technique is considered a highly promising optical modality, widely used for the chemical identification and characterization of molecular structures, providing detailed information on the structural arrangement, crystal orientations, phase, and polymorphism, molecular interactions and effects of bonding, chemical surrounding environment, and stress on samples. Raman spectroscopy has been appropriate to investigate both organic and inorganic components of dental tissues since it provides accurate and precise spectral information on present minerals through the observation of the characteristic energies of their vibrational modes. This method is becoming progressively important in biomedical research, especially for non-invasiveness, non-destructiveness, high biochemical specificity, low water sensitivity, simplicity in analyzing spectral parameters, near-infrared region capability, and in vivo remote potential by means of fiber-optics. This paper will address the application of Raman spectroscopy in different fields of dentistry, found to be the most relevant and prevalent: early recognition of carious lesions; bleaching products performance; demineralizing effect from low-pH foods and acidic beverages; and efficiency of remineralization agents. Additionally, this review includes information on fiber-optic remote probe measurements. All described studies concern caries detection, enamel characterization, and assessment indicating how and to what extent Raman spectroscopy can be applied as a complementary diagnostic method.publishersversionpublishe

Deterministic End-to-End Delay Guarantees in a Heterogeneous Route Interference Environment

Some of the known results for delivering deterministic bounds on end-to-end queuing delay in networks with constant packet sizes and constant link rates rely on the concept of Route Interference. Namely, it is required to know the number of flows joining on any output link in the whole network. In this paper we extend the existing results for the more generic cases of connection-oriented networks consisting of links with different capacities, carrying different traffic classes and packets of different sizes

A new record of Ratan goby - Ponticola ratan (Nordmann, 1840) (Pisces: Gobiidae) in the Black Sea, Romanian coastal waters

In August 2015 we managed to capture a specimen of ratan goby (Ponticola ratan) in the Romanian coastal waters of the Black Sea, near the locality of Sf. Gheorghe (Tulcea County). This is the 7-th signaling for this species in Romanian coastal waters. The previous 6 specimens were recorded in the period 1960-1993, between Mangalia (Constanţa County) and Sulina (Tulcea County). The species was identified by means of meristic characters (number of scales on medial line, number of spiny and soft rays), and morphological particularities (cycloid scales on the nape area and pectoral fin joint). Also, the measurements made, confirmed that the ratio between the head length and total length, which was 33% (TL=8.70 cm vs. Head Length=2.61cm). Another morphological character, specific to this species, is the lower jaw, which exceeds in length the upper jaw. Being a Ponto-Caspian endemite, with low population along the Bulgarian and Romanian coastline, we considered it important to point out this new record. Noting that, being known the trend of sporadic migration of this species, would not be excluded that global warming causes a shift from its normal distribution area, from northern and northeastern (Black Sea) to south-west. Therefore, future research may bring more notifications regarding this species in south-western area of the Black Se

Renovascular hypertension: mechanisms of development, clinical manifestation, management of treatment. Review of literature

This presentation is a review of international literature that elucidates the clinical manifestation, management of treatment, and mechanisms of renovascular hypertension. Another object of our work is to report some real clinical cases relating to this study and make a difference between international and Moldavian practice in the management of patients with renovascular hypertension. Hypertension in the presence of renal artery stenosis may not necessarily be renovascular hypertension. The two conditions may simply co-exist. Renovascular hypertension is usually symptomless, while hypertension that is difficult to control with antihypertensive therapy is probably the best indication as to whether further diagnostic evaluation is indicated. Some features of renovascular hypertension include: a worse prognosis than essential hypertension, less amenable to drug treatment, a greater risk of dose-dependent side effects, a higher risk of progression to accelerated hypertension and it may result in irreversible ischaemic failure of the affected kidney. Renal artery stenosis may be present in up to 30% of drug resistant hypertensive patients. Arteriosclerotic renovascular disease is an increasingly important cause of renal failure. Functional diagnostic tests for renovascular hypertension such as rapid sequence intravenous urography have now been superseded by the captopril challenge test and in particular scintigraphy following captopril provocation. Tests of prediction as to whether correction of a demonstrated renal artery stenosis will lead to an improvement in the blood pressure include renal vein renin estimations and scintigraphy. The key diagnostic procedure is renal angiography. The approaches to management primarily include appropriate antihypertensive therapy, while there is an increasing place for percutaneous transluminal angioplasty, with or without stenting of an occluding lesion. There is still a small place for corrective surgery. Renal ischaemia due to atherosclerotic renovascular disease is becoming an increasing problem in nephrology. Treatment should be directed at preserving or even restoring renal function

A New Species of the Gobiidae Family in Transylvania Waters: Racer Goby (Babka gymnotrachelus, Kessler 1857)

The racer goby (Babka gymnotrachelus) is one of the well represented Ponto-Caspian goby species in most Danube Delta Biosphere Reserve lakes and channels, including Razim-Sinoe lagoon complex and lower sector of the Danube. Also, the presence of this species is noted in some lakes near Bucharest. The presence of this species in Transylvania has not been reported until now, when our team, while conducting ichthyologic investigations, captured seven specimens from SomeÈ™ River and some of its tributaries, as follows: one specimen was caught in a channel adjacent to Èšaga Mare Lake, one specimen was caught in Someșul Mare River (Mica village, Cluj County), two specimens were captured from the confluence of the Someșul Mic River and FizeÈ™ River. Another two specimens were captured from Fizeș River (Fizeșu Gherlii village, Cluj County) and the last one was also caught from the Fizeș River (Sântioana village, Cluj County). It is possible that the species migrated in Someș Catchment from the Hungarian Danube sector, by the tributaries of Tisa River, or it might have originated from stocking material used in fish farms in Transylvania.The somatic, gravimetric and meristic measurements of the collected specimens were taken in the Acquaculture and Acquatic Organisms Phisyology laboratories from the University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca and correspond with those mentioned in the published literature regarding this species

Application of Unsupervised Multivariate Analysis Methods to Raman Spectroscopic Assessment of Human Dental Enamel

Funding Information: Acknowledgments: This work has been financially supported by Fundação para a Ciência e a Tecnolo-gia through the LIBPhys funding UID/FIS/ 04559/2021 and I. Otel PhD grant PD/BDE/143107/2018. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This work explores the suitability of data treatment methodologies for Raman spectra of teeth using multivariate analysis methods. Raman spectra were measured in our laboratory and obtained from control enamel samples and samples with a protective treatment before and after an erosive attack. Three different approaches for data treatment were undertaken in order to evaluate the aptitude of distinguishing between groups: A—Principal Component Analysis of the numerical parameters derived from deconvoluted spectra; B—PCA of average Raman spectra after baseline correction; and C—PCA of average raw Raman spectra. Additionally, Hierarchical Cluster Analysis were applied to Raman spectra of enamel measured with different laser wavelengths (638 nm or 785 nm) to evaluate the most suitable choice of illumination. According to the different approaches, PC1 scores obtained between control and treatment group were A—50.5%, B—97.1% and C—83.0% before the erosive attack and A—55.2%, B—93.2% and C—87.8% after an erosive attack. The obtained results showed that performing PCA analysis of raw or baseline corrected Raman spectra of enamel was not as efficient in the evaluation of samples with different treatments. Moreover, acquiring Raman spectra with a 785 nm laser increases precision in the data treatment methodologies.publishersversionpublishe

A fully automatic nerve segmentation and morphometric parameter quantification system for early diagnosis of diabetic neuropathy in corneal images

Diabetic Peripheral Neuropathy (DPN) is one of the most common types of diabetes that can affect the cornea. An accurate analysis of the nerve structures can assist the early diagnosis of this disease. This paper proposes a robust, fast and fully automatic nerve segmentation and morphometric parameter quantification system for corneal confocal microscope images. The segmentation part consists of three main steps. First, a preprocessing step is applied to enhance the visibility of the nerves and remove noise using anisotropic diffusion filtering, specifically a Coherence filter followed by Gaussian filtering. Second, morphological operations are applied to remove unwanted objects in the input image such as epithelial cells and small nerve segments. Finally, an edge detection step is applied to detect all the nerves in the input image. In this step, an efficient algorithm for connecting discontinuous nerves is proposed. In the morphometric parameters quantification part, a number of features are extracted, including thickness, tortuosity and length of nerve, which may be used for the early diagnosis of diabetic polyneuropathy and when planning Laser-Assisted in situ Keratomileusis (LASIK) or Photorefractive keratectomy (PRK). The performance of the proposed segmentation system is evaluated against manually traced ground-truth images based on a database consisting of 498 corneal sub-basal nerve images (238 are normal and 260 are abnormal). In addition, the robustness and efficiency of the proposed system in extracting morphometric features with clinical utility was evaluated in 919 images taken from healthy subjects and diabetic patients with and without neuropathy. We demonstrate rapid (13 seconds/image), robust and effective automated corneal nerve quantification. The proposed system will be deployed as a useful clinical tool to support the expertise of ophthalmologists and save the clinician time in a busy clinical setting

Development of Raman spectroscopy instrumentation for dental research

Raman spectroscopy is, in general, a non-invasive and non-destructive analytical technique used for the identification and analysis of chemical composition, and characterization of molecular structures, providing detailed information on structural arrangement, crystal orientations, crystallinity, phase, and polymorphism, as well as for the assessment of molecular interactions and the effects of bonding, chem-ical surrounding environment, and stress on samples. This method is becoming progressively important in biomedical research especially for its high biochemical specificity, low water sensitivity, simplicity in analyzing the spectral parameters, capability to work in the near-infrared region and in-vivo remote potential by means of fiber-optics. Raman technique has been confirmed to be a very appropriate tech-nique to characterize both organic and inorganic superficial components of dental tissues, enabling the acquisition of accurate and precise spectral information on present minerals through the observation of the characteristic energies of their vibrational modes. The sensitivity of this spectroscopic technique for changes in the symmetric stretching band of phosphate ions in the hydroxyapatite matrix could be used as a powerful tool and complementary method for early diagnostics of incipient caries and assessment of dental mineral content, even before signs of tooth demineralization are detected with conventional methods – visual-tactile examination combined with radiography. The present doctoral thesis aims to promote the application of Raman technique as a promising tool for dental examination, tooth decay and caries diagnostics, with emphasis on 1) the relevance and appropriateness of Raman spectroscopy in dentistry; 2) improvement of the accuracy for the spectral data processing and interpretation; 3) de-velopment of instrumentation for ex-vivo and in-vivo analysis, based on the design and assembly of a remote fiber-optic Raman probe with potential applications for the ex-vivo and in-vivo assessment of the human enamel and early caries diagnosis, presenting additionally a comparison study between Ra-man benchtop measurements and remote fiber-optic probe-based measurements. The accomplishment of the mentioned objectives should confirm the functioning principle of the Raman probe concept, im-prove the remote application, and help to implement the Raman technique in modern dentistry area, for a better counselling and assistance of the patients in preventing demineralization, the appearance of white spot lesion (WSL) and caries progression.A espectroscopia Raman é, em geral, uma técnica analítica não-invasiva e não-destrutiva, utilizada para a identificação e análise química, e a caracterização de estruturas moleculares, fornecendo informações detalhadas sobre o arranjo estrutural, orientações cristalinas, fase e polimorfismo, bem como para a avaliação das interações moleculares e os efeitos da ligação, ambiente químico circundante e tensão nas amostras. Este método é cada vez mais importante na investigação biomédica, especialmente devido a sua alta especificidade bioquímica, baixa sensibilidade à água, simplicidade na análise dos parâmetros espectrais, capacidade de trabalhar na região do infravermelho (NIR), potencial remoto e aplicação in-vivo por meio de fibra ótica. A técnica Raman é considerada muito apropriada para caracterizar componentes superficiais orgânicos e inorgânicos de tecidos dentais, permitindo a aquisição de informações espectrais exatas e precisas sobre os minerais presentes através da observação das energias características de seus modos vibracionais. A sensibilidade desta técnica espectroscópica para alterações na banda de alongamento simétrico dos iões de fosfato na matriz de hidroxiapatita pode ser usada como uma ferramenta poderosa e como um método adjuvante alternativo para diagnóstico precoce da cárie incipiente, início de lesão dentária ou perda de minerais, mesmo antes dos sinais de desmineralização serem detetados por métodos convencionais – a examinação visual-tátil em combinação com o exame radiológico. A presente tese visa promover a aplicação da técnica Raman como uma ferramenta promissora, bem como um método complementar, para o diagnóstico dentário, precisamente na deteção precoce da cárie incipiente e avaliação do estado de mineralização, demonstrando a 1) relevância e adequação da técnica por espectroscopia Raman na área dentária; 2) melhoria da precisão do processamento e interpretação dos dados espectrais; 3) desenvolvimento de instrumentação para análise efetuada ex- ou in-vivo, baseada no desenho e montagem de uma sonda remota Raman acoplada a fibras óticas, apresentando adicionalmente, um estudo comparativo entre as medições com o microscópio Raman e as medições remotas através da sonda. A concretização dos objetivos referidos deverá confirmar o princípio de funcionamento do conceito de sonda Raman, melhorar a aplicação remota e ajudar a implementar a técnica Raman na área da medicina dentária moderna, para um melhor aconselhamento e assistência dos pacientes na prevenção de desmineralização, aparecimento de lesão branca (WSL) e progressão da cárie

Evaluation of corneal nerve morphology for detection and follow-up of diabetic peripheral neuropathy

A Diabetes Mellitus, principalmente a Diabetes tipo 2, é uma das doenças crónicas mais prevalentes, e mais desafiantes. A diabetes atinge uma grande parte da população mundial, com este número a aumentar consideravelmente nos últimos anos. Esta doença metabólica afeta substancialmente a qualidade da vida, resultando em complicações graves, que são as principais causas da morbidez e mortalidade. Estão associadas à diabetes várias complicações crónicas. Uma das mais frequentes é a neuropatia diabética periférica (DPN) – a principal causa de incapacidade em diabéticos. Esta condição patológica inclui uma variedade de danos neurológicos periféricos, que são progressivos e que afetam principalmente os nervos sensitivos proximais e distais, bem como os nervos motores. O diagnóstico e a classificação da neuropatia é geralmente baseada numa combinação de sintomas clínicos e sinais neuropáticos, e em estudos electrofisiológicos. Adicionalmente, são utilizados outros métodos, como os estudos de condução nervosa (NCS) e os testes sensitivos quantitativos (QST). Estes métodos conferem maior exatidão ao diagnóstico efetuado por exame clínico, sendo extremamente úteis na caraterização da expressão neuropática. Estudos recentes mostraram que as anomalias dos nervos periféricos estão diretamente relacionadas com as alterações no plexo nervoso sub-basal corneano, sugerindo que a neuropatia periférica pode ser diagnosticada e avaliada através da análise morfométrica dos nervos da córnea. Esta abordagem tem recebido uma crescente atenção. A microscopia confocal da córnea (CCM) é uma técnica frequentemente utilizada para adquirir in vivo imagens dos nervos da córnea. Esta técnica é não-invasiva e permite a obtenção de imagens da córnea em tempo real. A microscopia confocal representa um método ideal para investigação e avaliação clínica, produzindo imagens com alta qualidade e permitindo a visualização das camadas e das células da córnea com uma resolução elevada. VI Apresentamos Aqui um estudo piloto em que se avalia a deteção e classificação da neuropatia periférica através da análise morfométrica dos nervos da córnea. O estudo consiste numa avaliação pormenorizada dum pequeno grupo de 12 voluntários não-diabéticos e 8 doentes diabéticos tipo 2, classificados consoante a presença e o grau de severidade da neuropatia. Os resultados que obtivemos são promissores e similares aos reportados em estudos anteriores. Os parâmetros Densidade de Fibras Nervosas (NFD), Comprimento de Fibras Nervosas (NFL), Largura de Fibras Nervosas (NFW) e Densidade de Branching de Nervos (NBD) apresentaram o melhor desempenho na avaliação da neuropatia diabética. Os valores de NFD, NFL e NBD são significativamente mais baixos (p <0.05) nos doentes diabéticos quando comparados com os controlos, e exibem correlações inversas com o grau de severidade da neuropatia. Os valores de NFW são significativamente superiores nos doentes diabéticos, variando com o grau de severidade da neuropatia. Os parâmetros NFD e NFL mostram diferenças estatisticamente significativas (p <0.05) entre os casos sem neuropatia e os doentes com neuropatia, mostrando também diferenças significativas (p <0.05) entre os grupos dos diabéticos (classificados consoante a severidade da neuropatia), diferenciando os grupos com grau ligeiro e moderado de neuropatia, do grupo de controlos não-diabéticos. Concluímos que a CCM pode ser utilizada com êxito para complementar os resultados de avaliação da neuropatia periférica, obtidos através de exames clínicos e electrofisiológicos. Palavras-Chave: diabetes, neuropatia diabética periférica, microscopia confocal da córnea, nervos da córnea, parâmetros morfométricos