[Application of autofluorescence microscopy and laser Induced fluorescence methods to study the dynamics of the demineralization primary teeth process in vitro]. / Primenenie autofluorestsentnoi mikroskopii i lazernoi fluometrii dlya izucheniya protsessa demineralizatsii vremennykh zubov in vitro.

OBJECTIVE: Improvement of methods for studying the processes of demineralization of hard tissues of temporary teeth. MATERIAL AND METHODS: The study included primaries second molars (n=11). Samples of primary teeth were placed in a test tube with a demineralizing solution for - 1, 4, 8, 21 and 31 days. The of primary teeth samples were examined using methods - laser induced fluorescence (LIF) and autofluorescence microscopy (AFM). Assessment of the degree of demineralization of samples of temporary teeth was carried out according to the score scale developed by us. RESULTS: The enamel of the samples is demineralized slowly and evenly for up to 8 days with minimal objective signs, starting from the 8th day of the experiment, there is a significant increase in demineralization indicators. By the 21st day, the peak of demineralization is reached with partial dissolution of the enamel, an increase in the fluorescence effect to 80 UE, and reaches a maximum of 4 points on the evaluation scale. Dentin's hard tissues are demineralized gradually without "sudden jumps" in the fluorescence effect and at the same rate throughout the experiment, reaching a maximum on 31 days (30 UE - LIF). Dentin demineralization is characterized by less dissolution, however, the phenomenon of delamination is determined by the type of exfoliation of the organic dentin matrix, starting from the 21st day of the experiment. CONCLUSION: Enamel and dentin of deciduous teeth demineralize at different rates and have a characteristic specificity of morphological changes. Logistic regression analysis showed the consistency of the classifier for the predictive accuracy of each unit of the proposed scale for assessing the degree of demineralization of temporary teeth samples.

Ex-vivo analysis of demineralisation on irradiated teeth using optical coherence tomography.

Head and neck cancer patients are prone to dental caries after radiotherapy. An ex-vivo study was conducted to assess the feasibility of optical coherence tomography (OCT) to detect tooth demineralization due to caries in irradiated teeth. Thirty-nine human molar teeth were subjected to caries lesion induction through irradiation (Group 1), pH cycling (Group 2-1), and both (Group 2-2). The OCT signal attenuation coefficient, µR was assessed and validated against microhardness test and scanning electron microscope (SEM). The µR for Group 1 increased from 10 Gy to 40 Gy, and subsequently decreased after irradiated to 50 Gy and 60 Gy due to damaged enamel microstructure. In Group 2-1, the µR decreased with duration of pH cycling from day 1 to day 14 due to the increase of porosity in enamel layer. However, the µR showed decreasing trend from day 14 to day 28 of pH cycling, resulted from mineral deposition in the enamel layer. Although no significant difference was found in the µR between Group 2-1 and 2-2, SEM of Group 2-2 demonstrated visually higher porosity and larger gaps between microstructures. Irradiation may accelerate caries damage to tooth microstructure by increasing its porosity and brittleness, but larger sample size may be needed to further prove the effect. OCT could potentially be used for early detection of tooth demineralization in vivo based on the measurable µR changes for all groups which are shown negatively correlated with microhardness value (p < 0.05).

Integrated Multiplex Sensing Clear Aligner for In Situ Monitoring of Dental Enamel Demineralization.

Clear aligners have become one of the most important tools in orthodontic treatment. However, over a lengthy period of orthodontic treatment, enamel demineralization or even dental caries could be susceptible for occurrence. Therefore, early diagnosis of enamel demineralization has been widely investigated. Nevertheless, for reasons including bulky monitoring equipment and complexity of operation, few techniques reported to date possessed clinical utility. The combination of flexible electronics and electrochemical sensing technology presented a promising strategy. Herein, an integrated multiplex sensing clear aligner (IMSCA) system, including a clear aligner with a multiplex sensor array patch, was developed for in situ monitoring of Ca2+, pH, and PO43- in the oral environment to provide a foundation for early diagnosis of enamel demineralization. The IMSCA exhibited a broad linear response range, great selectivity, temporal stability, reproducibility, and biological safety. Results of enamel demineralization simulating experiments and human permanent tooth demineralization experiments validate the capability of the IMSCA to indicate the occurrence of enamel demineralization. All results ultimately point to the promising clinical utility of the IMSCA, which facilitates the quantitative characterization of enamel demineralization in complex oral environments. This study provides a novel strategy in the early diagnosis of enamel demineralization.

Use of bioluminescence measurements for detection of artificial demineralization adjacent to orthodontic brackets.

PURPOSE: Enamel demineralization can occur as a side effect during orthodontic treatment with fixed appliances and should be detected as early as possible. A new approach to assess demineralization is a system consisting of a photosensitive protein that binds to free calcium ions at the enamel surface. A camera is then used to visualize the bioluminescence spots. This in vitro study aimed to evaluate the ability of the bioluminescence technology to assess artificially demineralized enamel adjacent to various orthodontic brackets. METHODS: In all, 108 human enamel samples were allocated randomly to groups with different orthodontic bracket material: stainless steel, titanium, ceramic. Initial lesions were created adjacent to the brackets. The samples were assessed by bioluminescence before and after demineralization. Images were assessed for presence of bioluminescence spots (yes/no). To quantify the bioluminescence measurements, the images' pixel values (P) were calculated within a defined area (F) adjacent to each bracket before and after demineralization. Quantitative light-induced fluorescence measurements (ΔF, ΔQ) were performed as the reference standard for demineralization. RESULTS: After demineralization, bioluminescence spots were visible (yes/no decision) in 87% of the samples. The pixel analysis of the bioluminescence spots showed significantly higher pixel values after demineralization compared to baseline (p < 0.0001). The bracket material had no influence on the bioluminescence measurements. All samples showed fluorescence loss with a median ΔF of -9.52% (±3.15) and a median ΔQ of -1.01%â€¯× mm2 (±3.34), respectively. CONCLUSION: The bioluminescence technology is a promising tool to demonstrate demineralization adjacent to different orthodontic brackets in vitro.

Ability of a Blue Hemoglobin-Based Liquid as a Novel Technology to Stain Initial Enamel Demineralization: A Proof-of-Concept in vitro Study.

During orthodontic treatment, enamel demineralization can occur. Its early detection is the basis for efficient preventive measures to arrest or remineralize lesions. In the present study, the application of a novel blue hemoglobin-based liquid (BlueCheck) was evaluated as proof of concept for detection of artificially demineralized smooth surfaces. 60 samples from extracted human posterior teeth were randomly assigned to four groups (15 per group). In 30 of these samples (groups A and B), superficial enamel was removed to create a ground surface. On the surface of other 30 samples (group C and D), orthodontic metal brackets were bonded. On each surface, BC liquid was applied and rinsed with water after 3 min (baseline). All surfaces were checked by two independent observers for presence of blue areas. On each sample, one side was covered by nail varnish to protect this enamel part from demineralization. The samples were demineralized with lactic acid (pH 4.6) for 7 days (group A and C) and 14 days (group B and D), respectively. Mineral loss was determined using quantitative light-induced fluorescence after demineralization. BlueCheck dye was again applied on the samples and evaluated for presence of stained areas. Histological sections were prepared from randomly selected samples and lesion depth was measured. Kruskal-Wallis test was used for group comparison (α = 0.05). After demineralization, median ΔF value for all samples was -8.25% indicating the presence of an initial demineralization. The difference of ΔF values was not statistically significant between samples at 7 or 14 days of demineralization, nor for samples with and without orthodontic brackets (p = 0.13). At baseline, none of the sample surfaces showed discoloration, whereas a distinctive blue color was visible after demineralization in all samples exposed to acid-exposed areas, corresponding to 100% sensitivity. The internal control surfaces (without demineralization) did not show any staining, corresponding to 100% specificity. Histologically measured lesion depths ranged between 200 and 254 µm. In this in vitro study, staining of demineralized enamel surface areas were shown to be reliable. Based on our results, this easily applicable product seems useful to be an adjuvant method to clinical examination to monitor oral health during an orthodontic treatment on tooth surfaces after removal of dental biofilm.

Non-invasive caries detection and delineation via novel laser-induced fluorescence with hyperspectral imaging.

Carious is a global chronic disease; 2 billion people and 520 million children suffer from permanent and primary teeth caries respectively. Early caries detection via precise, non-invasive, non-ionizing radiation is highly appreciated. Carious deteriorate the chemical structure of sound tooth tissues, with variation in its optical properties. In this study, customized laser-induced fluorescence system consists of non-ionizing laser light source and hyperspectral camera was developed for early caries detection. Tested tooth sample was illuminated with laser source of 385 nm and 5 mW power. The emitted spectrum signature for main tooth elements including enamel, dentin, stain, and caries were captured. Logarithmic scale of spectrum signature was applied in an attempt to enhance system sensitivity to fluorescent signal. Fluorescence signature at 500 nm secured the maximum fluorescence intensity difference for different tooth elements. Consequently 2D hyperspectral image at 500 nm was constructed. Enhanced 2D image was accomplished via nonlinear filter to enhance contrast. Segmentation via K mean clustering was adopted for precise caries delineation. This narrative, facile, non-invasive, non-ionizing technique experienced precise and accurate delineation of different caries stages (normal, moderate, and severe).

A novel method quantifying caries following orthodontic treatment.

This retrospective pilot study used a newly developed evaluation tool to assess the prevalence and incidence of White Spot Lesions (WSL) before and after multibracket appliance (MB) therapy. Digital photographs of 121 adolescent patients (63 ♂, 58 ♀) with metal brackets were analyzed retrospectively before and after MB therapy. The labial surfaces of anterior teeth, canine teeth, and premolars in the upper (UJ) and lower jaws (LJ) were evaluated using the Enamel Decalcification Index (EDI) by Banks and Richmond (Eur J Orthod, 16(1):19-25, 1994, levels 0-3) and a specially developed digitally scaled graticule with concentric circles to quantify the extent of WSL (in %). The statistical data analysis was based on crosstabulations and logistic regression. Before MB, 69.4% of the patients presented at least one WSL and 97.5% after, an increase of 28.1%. Before MB, 18.4% of the tooth surfaces (TS) showed an EDI level of 1-3. After MB, 51.8% of the TS featured WSL. 18.2% of the TS showed a WSL to the extent of ≥ 20-100% before and 52.3% after MB. The incidence in the UJ (71-79%) as well as the LJ (64-76%) was highest for the first and second premolars and lowest for LJ incisors (22-35%). The probability for developing a new distal WSL is higher than developing gingival, mesial or occlusal WSL. Labial MB therapy drastically increases the risk of developing WSL. We verified a concise quantification of the extent of labial WSL with the evaluation index.

ORAL HYGIENE IN CHILDREN WITH DISTURBANCES IN TOOTH FORMATION WHO WERE AFFECTED AS A CONSEQUENCE OF THE ChNPP ACCIDENT. / STAN GIGIIeNY POROZhNYNY ROTA U DITEI Z PORUShENNIaMY FORMUVANNIa ZUBIV, POSTRAZhDALYKh VNASLIDOK AVARIÏ NA ChAES.

OBJECTIVE: evaluation of oral hygiene to enhance the prophylaxis of complications specifically of dental caries inchildren with disturbances in tooth formation (DTF) who live on radiologically contaminated territories after theChornobyl NPP (ChNPP) accident. MATERIALS AND METHODS: Children aged 6-14 years (n = 1470) with DTF were the study subjects examined in 2012-2016. Among them there were (n = 528) residents of the zones III and IV of radiological contamination after theChNPP accident with 137Cs soil contamination density 1-15 Ci/km2. The effective radiation dose in them was notexceeding 1 mSv/year. The Green-Vermillion and Silness-Loe oral hygiene indices were assesses within clinicalexamination methods. RESULTS: The worth oral hygiene was revealed in children having got the DTF, compensated chronic diseases oforgans and systems, and in those with burdened radiation history. The Green-Vermilion and Silness-Loe indices were1.7 ± 0.51 and 1.65 ± 0.46 respectively. CONCLUSIONS: A significant deterioration in oral hygiene confirmed by the highest values of the Green-Vermillion index (1.7 ± 0.51; p < 0.001 - «unsatisfactory oral hygiene¼ criterion) and Silness-Loe index (1.65 ± 0.46; p < 0.001 -«poor oral hygiene¼ criterion) was found in children with DTF aged 6-14 years being residents of contaminated areasas a result of the Chernobyl accident. The revealed deterioration may be due to a set of negative factors, includingthe impact of ionizing radiation in low doses and peculiarities of social status. Results of the questioning of surveyed pediatric contingents both having got an DTF and with no defects of the hard tissues of teeth indicate aninsufficient level of knowledge and skills in hygienic care of oral cavity regardless of the area of residence.Development of a set of measures to prevent the DTF complications in children should be carried out taking intoaccount the state of oral hygiene, level of knowledge and skills in oral care, and include the use of hygiene products, namely toothpastes and anti-caries mouthwashes.

Raman spectroscopy for early detection and monitoring of dentin demineralization.

Early detection of dental caries and variations in composition/structure of both enamel and dentin represents an important issue in modern dentistry. Demineralization has been associated to teeth discoloration, development of caries, and formation of cavities. OBJECTIVE: In this study, we systematically monitored the processes of demineralization/remineralization in dentin samples by means of three different spectroscopic techniques, namely, Raman spectroscopy, X-Ray Photo-electron spectroscopy (XPS), and X-Ray Diffractometry (XRD). METHODS: Bovine dentin samples were first exposed to acidic solutions and their structure systematically monitored as a function of time and pH. Then, the samples were rinsed in artificial saliva to simulate remineralization. RESULTS: The above three spectroscopic techniques provided quantitative structural information spanning from the nanometer to the millimeter scale of sample penetration depth. An irreversible level of demineralization was reached when dentin was exposed to pH 2 beyond a time threshold of 6h, successive treatments with artificial saliva being unable to restore the mineral fraction. On the other hand, short-term treatments at pH 5 and long-term treatments at pH 6 could partially or completely recover the dentin structure within one week of remineralization treatment. SIGNIFICANCE: Two specific Raman parameters, namely, the bandwidth of the symmetric phosphate-stretching signal and the mineral-to-matrix intensity ratio, showed strong correlations with XPS and XRD data, and matched laser microscopy observations. Such correlations open the path to apply Raman spectroscopy in monitoring dentin demineralization in vivo and provide quantitative working algorithms for the prevention of oral caries.

Influence of customized therapy for molar incisor hypomineralization on children's oral hygiene and quality of life.

OBJECTIVE: The aim of this clinical follow-up study was to demonstrate the effects of different therapeutic strategies for hypomineralized teeth on patients' oral health. The treatment results were characterized by changes in the extent of hypersensitivity and plaque accumulation, as well as reductions in nutritional restrictions. MATERIAL AND METHODS: The impacts of therapy, including the use of fluoride varnish, fissure sealants, fillings, and stainless steel crowns, were evaluated in 78 children (mean age 8.5 years). We followed recommendations according to the Molar Incisor Hypomineralisation Treatment Need Index for customized treatment. The Quigley Hein Index, the Schiff Cold Air Sensitivity Scale, Wong-Baker Faces Scale, and dietary-limiting parameters were assessed before and after therapy for comparison. RESULTS: Plaque accumulation and hypersensitivity decreased after completion of therapy. The improvements were greater for individual teeth (Quigley Hein Index for teeth treated with stainless steel crowns from 4.19 to 2.54) than for those of the whole dentition (high-severity category from 2.67 to 2.20). Problems with food intake were minimized via therapy, with the greatest influence observed for patients who were also in the high-severity category. CONCLUSIONS: Therapy for affected teeth in children has positive effects on oral health and quality of life.

Evaluation of mineral loss in primary and permanent human enamel samples subjected to chemical demineralization by international caries detection and assessment system II and quantitative light-induced fluorescence™: An in vitro study.

PURPOSE: The purpose of the study was to understand the mineral loss in primary and permanent enamel samples and an attempt is made to standardize the process of chemical demineralization to generate more meaningful results in research studies involving the remineralization of demineralized samples. MATERIALS AND METHODS: Due to variability among enamel samples theoretically, it is impossible to standardize demineralization by running time-based chemical demineralization cycle without frequent monitoring. Instead of carrying out demineralization cycles for a fixed duration of time, we quantified the mineral loss 24 hourly using the International Caries Detection and Assessment System (ICDAS) and Quantitative Light-induced Fluorescence System (QLF™). Twenty primary and permanent enamel samples were subjected to demineralization, and ICDAS and QLF™ evaluation were done at 0, 24, 48, 72, 96, 120, 144, and 168 h of demineralization. RESULTS: The first visual change in permanent enamel is appreciated at 24 h (ICDAS II code1, QLF™ code1 -16.353 - ΔF) of demineralization, at 48 h (ICDAS II code2, QLF™ code2, -24.515 - ΔF), there was localized white spot lesion in permanent enamel and remained until 96 h (ICDAS II code 2, QLF™ code 2, -25.739 - ΔF) of demineralization. In primary samples, distinct visual change was seen at 24 h (ICDAS II code2, QLF™ code2, -19.431 - ΔF), and at 48 h clinically, there was a distinct visual change, but optically mild enamel breakdown was appreciated (ICADSII code 2 QLF™ code3, -27.201 - ΔF), which remained constant till 120 h of demineralization (ICDAS II code2 QLF™ code3 -37.645 - ΔF). CONCLUSION: Different samples demineralize at different rates. The demineralization in primary samples was 1.25 times higher than permanent samples. Recommendation: due to inherent variability in the samples continuous monitoring of the demineralization process on a 24 hourly basis is required to standardize the process.

Early detection of enamel demineralization by optical coherence tomography.

Enamel is the outermost layer of the tooth that protects it from invasion. In general, an acidic environment accelerates tooth demineralization, leading to the formation of cavities. Scanning electron microscopy (SEM) is conventionally used as an in vitro tool for the observation of tooth morphology changes with acid attacks. Yet, SEM has intrinsic limitations for the potential application of in vivo detection in the early demineralization process. In this study, a high-resolution optical coherence tomography (OCT) system with the axial and transverse resolutions of 2.0 and 2.7 µm in teeth has been utilized for characterizing the effect of the acidic environment (simulated by phosphoric acid) on the enamel topology. The scattering coefficient and the surface roughness of enamel can be directly derived from the OCT results, enabling a quantitative evaluation of the topology changes with demineralization. The dynamic process induced by the acid application is also recorded and analyzed with OCT, depicting the evolution of the demineralization process on enamel. Notably, the estimated enamel scattering coefficient and surface roughness significantly increase with the application time of acid and the results illustrate that the values of both parameters after demineralization are significantly larger than those obtained before the demineralization, illustrating both parameters could be effective to differentiate the healthy and demineralized teeth and determine the severity. The obtained results unambiguously illustrate that demineralization of the tooth surface can be successfully detected by OCT and further used as an indicator of early-stage cavity formation.

Desafios clínicos no tratamento de hipomineralização molar incisivo / Clinical challenges in the treatment of incisive molar hypomineralization

Introdução: Um dos defeitos de esmalte que vem desafiando os odontopediatras é a Hipomineralização Molar-Incisivo (HMI), uma alteração de origem sistêmica caracterizada pela diminuição da mineralização de um até quatro primeiro molar permanente e que surge frequentemente associada aos incisivos permanentes, os quais podem estar, igualmente, afetados. Objetivo: O propósito deste trabalho é realizar uma revisão da literatura sobre as possibilidades de tratamento em molares afetados pela HMI. Método: Através de uma revisão de literatura, foi feito buscas nas bases de dados Biblioteca Virtual em Saúde, Scientific Electronic Library Online (Scielo) e Google Acadêmico. Os termos utilizados foram hipomineralização, molar, incisivo, anomalias. Resultados: Os tratamentos variam desde aplicação tópica de flúor à restaurações e exodontias. A decisão do tratamento depende do grau de acometimento do dente com HMI. A utilização de vernizes fluoretados são essenciais no início de todo tratamento com a finalidade de diminuir a sensibilidade presente nesses casos. Conclusão: Por meio desta, concluiu-se que, o estabelecimento de um correto plano de tratamento é fundamental para proservação do elemento dental, sendo necessário o conhecimento dessa alteração para o profissional fazer a melhor escolha(AU)

Introduction: One of the enamel defects that is a challenge to the pediatric dentists is Molar-Incisive Hipomineralization (HMI), an alteration of systemic origin characterized by a decrease in mineralization from one to four permanent first molars and frequently associated with permanent incisors, which may also be affected. Objective: The purpose of this work is to review the literature on treatment possibilities in molars affected by HMI. Method: Through a bibliographic review, the databases of the Virtual Health Library, Scientific Electronic Library Online (Scielo) and Google Scholar were searched. The terms used were hypomineralization, molar, incisor, anomalies. Results: Treatments range from topical fluoride application to restorations and extractions. The decision of the treatment depends of the degree of affection in the tooth with HMI. The use of fluoride varnishes is essential at the beginning of any treatment the objective is to reduce the sensitivity present in these cases. Conclusions: Through this, it was concluded that, the establishment of a correct plan of treatment is fundamental for the dental element preservation, being necessary the knowledge of this alteration for the professional to make the best choice(AU)

Hipomineralização molar incisivo em odontopediatria: considerações gerais / Molar incisor hypomineralization in pediatric dentistry: general considerations

Introdução: Hipomineralização molar incisivo (HMI) engloba a hipomineralização do esmalte que aflige um ou mais primeiros molares permanentes e que pode acometer também incisivos permanentes. Segundos pré-molares e caninos permanentes também podem mostrar-se envolvidos, assim como alguns decíduos, entre os quais cita-se os segundos molares. Objetivo: O objetivo do presente artigo foi averiguar as manifestações clínicas ocasionadas pela hipomineralização molar incisivo sob o enfoque da odontopediatria. Método: Realizou-se estudo de revisão bibliográfica com busca nas bases de dados LILACS e Google Acadêmico. Na base LILACS empregou-se a expressão de busca: hipomineralização molar incisivo and odontopediatria. Na base de dados Google Acadêmico utilizou-se a expressão de busca: hipomineralização molar incisivo and odontopediatria. Resultados: É importante que se proceda ao diagnóstico precoce e correto da HMI, baseando-se na realização de anamnese detalhada, que seja capaz de investigar a existência de possíveis doenças no período da infância e que se proceda concomitantemente ao feitio de exame clínico para que se estabeleça um prognóstico adequado. Conclusões: Concluiu-se que o diagnóstico precoce da HMI, firmado imediatamente e concomitantemente no momento em que ocorre a erupção dental e que uma abordagem com cunho preventivo evita a realização de tratamentos com maior complexidade e é capaz de minimizar eventuais danos, oriundos de algumas manifestações clínicas da HMI que podem ocorrer, como: cárie dentária; desgaste de tecido dentário; perda de esmalte e sensibilidade dentária, dentre outros(AU)

Introduction: Molar incisor hypomineralization (MIH) encompasses the hypomineralization of the enamel that afflicts one or more first permanent molars and may also affect permanent incisors. Second premolars and permanent canines may also be involved, as well as some deciduous ones, among which the second molars are mentioned. Objective: The aim of the present article was to investigate the clinical manifestations caused by molar incisor hypomineralization under the pediatric dentistry approach. Method: A bibliographic review study was carried out with search in the databases LILACS and Google Scholar. In the LILACS database, the search expression was used: molar incisor hypomineralization and pediatric dentistry. In the Google Scholar database we used the search term: molar incisor hypomineralization and pediatric dentistry. Results: It is important to carry out the early and correct diagnosis of MIH, based on detailed anamnesis, which is capable of investigating the existence of possible diseases in the period of childhood and proceeding concomitantly to the clinical examination form to establish an adequate prognosis. Conclusions: It was concluded that the early diagnosis of MIH, established immediately and concomitantly at the time of dental eruption and that a preventive approach avoids the accomplishment of treatments with greater complexity and is capable of minimizing any damages, arising from some clinical manifestations of MIH that may occur, such as: dental caries; wear of dental tissue; loss of enamel and tooth sensitivity, among others(AU)

An unusual disordered alveolar bone material in the upper furcation region of minipig mandibles: A 3D hierarchical structural study.

Teeth are subjected to compressive loads during mastication. Under small loads the soft tissue periodontal ligament (PDL) deforms most. However when the loads increase and the PDL is highly compressed, the tooth and the alveolar bone supporting the tooth, begin to deform. Here we report on the structure of this alveolar bone in the upper furcation region of the first molars of mature minipigs. Using light microscopy and scanning electron microscopy (SEM) of bone cross-sections, we show that this bone is hypermineralized, containing abundant small pores around 1-5 µm in diameter, lacunae around 10-20 µm as well as larger spaces. This bone does not possess the typical lamellar motif or other repeating structures normally found in cortical or trabecular mammalian bone. We also use high resolution focused ion beam scanning electron microscopy (FIB-SEM) in the serial surface mode to image the 3D organization of the demineralized bone matrix. We show that the upper furcation bone matrix has a disordered isotropic structure composed mainly of individual collagen fibrils with no preferred orientation, as well as highly staining material that is probably proteoglycans. Much larger aligned arrays of collagen fibers - presumably Sharpey's fibers - are embedded in this material. This unusual furcation bone material is similar to the disordered material found in human lamellar bone. In the upper furcation region this disordered bone comprises almost all the volume excluding Sharpey's fibers. We surmise that this most unusual bone type functions to resist the repeating compressive loads incurred by molars during mastication.

Evaluation of laser fluorescence in combination with photosensitizers for detection of demineralized lesions.

BACKGROUND AND OBJECTIVES: Early detection of caries plays an important role in its prognosis. This study sought to assess the efficacy of laser fluorescence alone and in combination with photosensitizers for detection of demineralized smooth-surface lesions of permanent teeth. MATERIALS AND METHODS: This in vitro experimental study was conducted on 60 extracted sound premolars. Four windows measuring 2 x 2 mm were created on each tooth. Forty out of 60 teeth were subjected to demineralization cycle. All teeth were then sectioned and subjected to DIAGNOdent Pen (Kavo, Biberach, Germany) alone and in combination with 0.2-mM tetrakis N-methylpyridyl porphyrin (TMPyP) fluorescent dye, 2% methylene blue and 2% new methylene blue photosensitizers. The results of histological analysis of sections served as the gold standard. The correlation of the results with the gold standard was assessed using the Pearson's correlation coefficient and receiver operating characteristic (ROC) curve. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the four techniques were evaluated as well. RESULTS: The correlation between the results of DIAGNOdent laser with TMPyP dye and the gold standard was significant (P < 0.05). Also, this technique had the highest sensitivity while DIAGNOdent laser alone had the highest specificity. CONCLUSION: Laser fluorescence with TMPyP fluorescent dye has suitable efficacy for early detection of initial enamel lesions.

Remineralizing Potential of Nano-Silver-Fluoride for Tooth Enamel: An Optical Coherence Tomography Analysis

Objective: To evaluate the use of nanosilver fluoride in the enamel remineralization process through optical coherence tomography. Material and Methods: All samples were submitted to demineralization process by pH cycling during 14 days and randomly distributed into three groups (n = 11): Nanosilver Fluoride (NSF), Sodium fluoride (NaF), and negative control. Optical coherence tomography images were acquired at three different moments: initial stage (T0), post caries formation (T1), and post pH cycling (T2). The integrity of the enamel surface and the measurement of the volume loss for the tissue after pH cycling in comparison to initial images were obtained from optical coherence tomography images. Results: After analyzing the exponential decay of A-scans from each group, it was possible to identify differences in light propagation among samples. In T1 it is not possible to visualize the dentin-enamel junction, probably due to the higher back scattering of the demineralized enamel, which does not allow light to reach the dentin. The decay curves obtained from NaF and nanosilver fluoride groups showed similar behavior, while the negative group showed lower extinction coefficient. Conclusion: Nanosilver fluoride showed the best effect against caries compared to conventional fluoride treatments.

In Situ Effect of Intra-Oral Application of Pastes Containing CPP-ACP or CPP-ACPF Against Initial Enamel Erosion

Objective: To evaluate in situ the effect of toothpastes containing casein phosphopeptide - amorphous calcium phosphate (CPP-ACP) and casein phosphopeptide-amorphous calcium phosphate associated to fluoride (CPP-ACPF) on initial erosion prevention. Material and Methods: Bovine enamel blocks (n = 192) were randomly assigned into 4 phases according to the baseline surface hardness: GI: CPP-ACP Paste (MI Paste™), GII: CPP-ACPF Paste (MI Paste Plus™), GIII: Fluoridated paste and GIV: Placebo Paste. In each of the 4 crossover phases, twelve volunteers wore intraoral palatal appliances containing 4 enamel blocks for 2 hours, then the tested treatments were applied intraorally (3 min) and the appliance was maintained in the mouth for another 3 hours. After, the appliances were removed and immersed in hydrochloric acid (0.01 M, pH 2.3) for 30 seconds to promote erosive demineralization. The final surface hardness was evaluated and percentage of surface hardness loss was calculated. The data were analyzed by ANOVA and Tukey's test (α = 5%). Results: The application of CPP-ACP paste, independent of fluoride content, resulted in significant lower enamel hardness loss (GI: 9.26% ±3.48 and GII: 9.14% ±1.73) compared to NaF (GIII: 15.5% ± 3.94) and placebo (GIV: 16.7% ± 4.07) pastes, which did not show difference between them. Conclusion: The CPP-ACP pastes were able to reduce initial erosive demineralization in relation to fluoride and placebo pastes. Nevertheless the formulation of CPP-ACP with fluoride did not provide an additional benefit.

Assessment of the Raman spectroscopy effectiveness in determining the early changes in human enamel caused by artificial caries.

Current diagnostic methods for enamel caries detection are unable to detect caries lesions at a very early stage. Previous studies indicated that Raman spectroscopy is a promising and effective tool for the detection of early caries. In our previous work, we showed that several independent parameters obtained during the analysis of the Raman spectra of enamel allow for the identification of carious lesions formed in the oral cavity (natural caries). The aim of this research was to estimate the effectiveness of Raman spectroscopy in the determination of specific changes in human enamel affected by artificial caries. The values of parameters obtained in a previous study were compared with those obtained in this work. Moreover, the direction of parameter value changes during caries formation was checked, and also compared with earlier results. The results show that Raman maps permit the determination of local variations in the enamel structure affected by the early demineralization process. As follows from these and previous results a few parameters such as depolarization ratio, polarization anisotropy, position, intensity and full width at half maximum of the Raman band allow for the identification of the enamel caries changes. This investigation contributes to the development of Raman spectroscopy for the identification of caries at a stage before visual changes in enamel.

Classification of dental diseases using hyperspectral imaging and laser induced fluorescence.

PURPOSE: Early diagnosis of tooth enamel demineralization, and dentin caries lesions, present a valuable solution to avoid or decrease their deleterious effect. The aim of this study was to design a simple, effective, and non-invasive technique, employing a novel laser wavelength to classify and differentiate between various tooth abnormalities in-vitro, by estimating wavelengths, showing distinctive appearance for each tooth class. METHODS: This study implies a fluorescence hyperspectral imaging system employing a 395-nm laser diode source, irradiating a pre-diagnosed 12 molars and premolars teeth. The obtained reconstructed images were displayed and processed by HSAnalysis2XL, accompanied by a custom made digital, and image signal processing algorithms, revealing the exact wavelengths, characterizing the fluorescence of each tooth pre-diagnosed class. RESULTS: The proposed hyperspectral imaging system was able to discriminate between normal, and abnormal dental classes for the entire specimens. Furthermore, a series of wavelengths, noting each lesion individually were obtained from the spectroscopic hyperspectral output. The root calculus, white spot, dentin caries, and enamel caries have a bright visual appearance at λ3 = 702 nm, λ5 = 771 nm, and λ6 = 798 nm respectively. Consequently, these abnormalities exhibit a dark appearance at λ1 = 421 nm, λ2 = 462 nm, and λ4 = 734 nm. The wavelength selections were confirmed by the grayscale image outcomes. CONCLUSIONS: This study provides a set of wavelengths that can be employed by dentists to diagnose white spot, root calculus, and enamel dentin caries lesions under the irradiation of a new UV-vis laser illumination source without, any hazardous thermal or mechanical effects.