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1.
J Adhes Dent ; 23(6): 505-512, 2021 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-34817966

RESUMO

PURPOSE: A new two-step self-etch adhesive (2-SEA) free of hydrophilic monomers was evaluated. Its microtensile bond strength (µTBS) to dentin under various aging conditions, interfacial gap formation, water sorption/solubility, and formation of an acid-base resistant zone (ABRZ) were evaluated and compared with a gold-standard 2-SEA. MATERIALS AND METHODS: The new 2-SEA G2-Bond Universal (G2; GC) was compared to Clearfil SE Bond 2 (CSE2, Kuraray Noritake). Their µTBS to sound coronal dentin was tested after 1 week, 10,000 thermal cycles (TC), 20,000 TC, 6 months and 1 year. Failure mode was determined using scanning electron microscopy (SEM). Gap formation at the interface of 2-mm deep tapered cavities with an enamel border was observed using swept-source optical coherence tomography after 1 day, 1 week, 10,000 TC, and 20,000 TC. In addition, water sorption and solubility of the bonding agents was measured, and ABRZ formation was evaluated using SEM. RESULTS: There was no significant difference in µTBS between G2 and CSE2 (p > 0.05), and the aging conditions had no significant effect on µTBS (p > 0.05). In all groups, cohesive failures prevailed (55%-95%). Interfacial gap formation was initially similar for both adhesives (p > 0.05), but G2 exhibited a significantly lower gap formation than CSE2 after TC (p < 0.05). The water sorption of G2 was significantly lower compared to CSE2 (p < 0.05), and their solubility was statistically similar (p > 0.05). ABRZ of similar thickness was observed with both adhesives. CONCLUSION: The new 2-SEA exhibited stable dentin bonding and increased hydrophobicity resulting from the absence of hydrophilic monomers.

2.
Clin Oral Investig ; 2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34383144

RESUMO

OBJECTIVE: To investigate the anti-demineralization potential of a newly developed surface reaction-type pre-reacted glass-ionomer (S-PRG) filler containing self-adhesive resin cement against acidic attacks on the dentin surface. MATERIALS AND METHODS: A total of 32 bovine teeth were used. Cavities were prepared on crown dentin slaps and filled with three self-adhesive resin cement: (1) S-PRG-based cement, (2) Si-based cement, and (3) RelyX cement. Specimens were then subjected to pH cycling for 28 days, and the depth of demineralization was assessed using swept-source optical coherence tomography (SS-OCT) after 7, 14, 21, and 28 days. Sixty-four root dentin blocks were divided into four groups and then subjected to a pH cycling procedure with the aforementioned three material blocks and one negative control. The mineral loss was observed using transverse microradiography (TMR), and the surface microhardness (SMH) test was conducted to investigate the mechanical properties of treated dentin surfaces. RESULTS: The depth of demineralization for the S-PRG-based cement was significantly lower than that of the Si-based cement after 7, 21, and 28 days. Conversely, the RelyX cement was not significantly different from the Si-based cement after 7, 14, and 21 days (p < 0.05). Regarding the TMR and SMH test, the S-PRG-based cement showed the least mineral loss with the highest resistance to acidic challenge. CONCLUSION: The S-PRG filler containing resin cement can reduce mineral loss and promote remineralization of dentin substrate and has the potential to preserve dentin integrity and resist acidic attack. Clinical significance Self-adhesive resin cement containing S-PRG fillers maintained the surface integrity of dentin after exposure to 28 days of acidic challenge with a significant anti-demineralization effect.

3.
Materials (Basel) ; 14(8)2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33918865

RESUMO

The purpose of this study was to evaluate the mechanism of action and the inhibiting effects of two types of desensitizers against dentin demineralization using pre-demineralized hypersensitivity tooth model in vitro. In this study, we confirmed that a hypersensitivity tooth model from our preliminary experiment could be prepared by immersing dentin discs in an acetic acid-based solution with pH 5.0 for three days. Dentin discs with three days of demineralization were prepared and applied by one of the desensitizers containing calcium fluoro-alumino-silicate glass (Nanoseal, NS) or fluoro-zinc-silicate glass (Caredyne Shield, CS), followed by an additional three days of demineralization. Dentin discs for three days of demineralization (de3) and six days of demineralization (de6) without the desensitizers were also prepared. The dentin discs after the experimental protocol were scanned using swept-source optical coherence tomography (SS-OCT) to image the cross-sectional (2D) view of the samples and evaluate the SS-OCT signal. The signal intensity profiles of SS-OCT from the region of interest of 300, 500, and 700 µm in depth were obtained to calculate the integrated signal intensity and signal attenuation coefficient. The morphological differences and remaining chemical elements of the dentin discs were also analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. SS-OCT images of CS and NS groups showed no obvious differences between the groups. However, SS-OCT signal profiles for both the CS and NS groups showed smaller attenuation coefficients and larger integrated signal intensities than those of the de6 group. Reactional deposits of the desensitizers even after the additional three days of demineralization were observed on the dentin surface in NS group, whereas remnants containing Zn were detected within the dentinal tubules in CS group. Consequently, both CS and NS groups showed inhibition effects against the additional three days of demineralization in this study. Our findings demonstrate that SS-OCT signal analysis can be used to monitor the dentin demineralization and inhibition effects of desensitizers against dentin demineralization in vitro.

4.
Dent Mater J ; 40(2): 379-384, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33100300

RESUMO

The effect of warm air-blowing on the sealing ability of two one-bottle and one two-bottle silane-containing universal adhesives (UAs) applied to lithium disilicate ceramics (LDS) was evaluated. Tapered cavities prefabricated in LDS blocks (IPS e.max CAD) were treated by the adhesives, air-blown either with normal air (23±1°C) or warm air (60±5°C), and filled with a flowable resin composite. Interfacial gap formation was observed using swept-source optical coherence tomography immediately after filling, after 24 h, 5,000 and 10,000 thermal cycles, and an additional 1-year water storage. Specimens bonded using normal air-blown one-bottle UAs exhibited a significantly higher gap formation than the two-bottle UA (p<0.001), and detached within 24 h. Warm air-blowing significantly decreased the gap formation of one-bottle UAs (p<0.001), but the specimens dislocated within 24 h or during thermocycling. The two-bottle UA withstood all aging procedures and warm air-blowing significantly decreased its 1-year gap formation compared to normal air-blowing (p=0.002).


Assuntos
Colagem Dentária , Silanos , Cerâmica , Cimentos Dentários , Porcelana Dentária , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície
5.
Sensors (Basel) ; 20(21)2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33113981

RESUMO

The aim of this study was to assess the utility of 3D imaging of optical coherence tomography (OCT) for the diagnosis of occlusal tooth wear ex vivo. Sixty-three extracted human molars with or without visible tooth wear were collected to take digital intraoral radiography and 3D OCT images. The degree of tooth wear was evaluated by 12 examiners and scored using 4-rank scale: 1-slight enamel wear; 2-distinct enamel wear; 3-tooth wear with slight dentin exposure; 4-tooth wear with distinct involvement of dentin. The degree of tooth wear was validated by the histological view of confocal laser scanning microscopy (CLSM). The sensitivity, specificity, and area under the curve (AUC) of receiver operating characteristic analysis were calculated. Diagnostic accuracy was compared with the agreement with CLSM observation using weighted kappa. The results were statistically analyzed at a significance level of α = 0.05. Three-dimensional OCT showed significantly higher sensitivity (p < 0.05) for all the diagnostic thresholds of enamel wear and dentin exposure than digital radiography (0.82, 0.85, and 0.79 vs. 0.56, 0.52, and 0.57, respectively). Three-dimensional OCT showed higher AUC and kappa coefficients than digital radiography (p < 0.05), where mean AUC and Kappa values were 0.95 and 0.76 for OCT and 0.92 and 0.47 for radiography, respectively. No significant difference of specificity was observed (p > 0.05). Three-dimensional OCT could visualize and estimate the degree of tooth wear and detect the dentin exposure at the tooth wear surface accurately and reproducibly. Consequently, a new guideline for tooth wear assessment can be proposed using OCT.


Assuntos
Tomografia de Coerência Óptica , Desgaste dos Dentes , Humanos , Imageamento Tridimensional , Curva ROC , Sensibilidade e Especificidade , Desgaste dos Dentes/diagnóstico por imagem
6.
Jpn Dent Sci Rev ; 56(1): 109-118, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33033549

RESUMO

Optical coherence tomography (OCT) is an imaging technique that can visualize the internal biological structure without X-ray exposure. Swept-source OCT (SS-OCT) is one of the latest version of OCT, wherein the light source is a tunable laser that sweeps near-infrared wavelength light to achieve real-time imaging. The imaging depth of OCT is highly influenced by the translucency of the medium. The medium that does not transmit light and the deeper structure beyond the range of light penetration depth are not relevant for OCT imaging. In OCT, sound enamel is almost transparent at the OCT wavelength range, and enamel and dentin can be distinguished from each other as the dentin-enamel junction (DEJ) appears as a dark border. Demineralized enamel and dentin are imaged as bright zones because of the formation of numerous micro-porosities where the backscatter of OCT signal is increased. In cavitated caries at interproximal or occlusal hidden zone, the upper margin of the cavity reflects the signal showing a distinct bright border in the SS-OCT image. SS-OCT is capable of determining crack penetration depth even when the cracks extended beyond the DEJ. SS-OCT has a high degree of sensitivity and specificity for the detection of dental caries and tooth cracks. SS-OCT is also capable of detecting non-carious cervical lesions and occlusal tooth wear in cross-sectional views to estimate the amount of tooth structure loss.

7.
Sci Rep ; 10(1): 15754, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32978464

RESUMO

Optical coherence tomography (OCT) can create cross-sectional images of tooth without X-ray exposure. This study aimed to investigate the diagnostic accuracy of 3D imaging of OCT for proximal caries in posterior teeth. Thirty-six human molar teeth with 51 proximal surfaces visibly 6 intact, 16 slightly demineralized, and 29 distinct carious changes were mounted to take digital radiographs and 3D OCT images. The sensitivity, specificity and area under the receiver operating characteristic curve (AUC) for the diagnosis of enamel caries and dentin caries were calculated to quantify the diagnostic ability of 3D OCT in comparison with digital radiography. Diagnostic accuracy was evaluated by the agreement with histology using weighted Kappa. OCT showed significantly higher sensitivity, AUC and Kappa values than radiography. OCT can be a safer option for the diagnosis of proximal caries in posterior teeth that can be applied to the patients without X-ray exposure.


Assuntos
Cárie Dentária/diagnóstico por imagem , Imageamento Tridimensional , Dente Molar/diagnóstico por imagem , Tomografia de Coerência Óptica , Humanos , Sensibilidade e Especificidade
8.
J Dent ; 94: 103300, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32070754

RESUMO

OBJECTIVES: To evaluate the sealing performance of self-etch adhesives (SEA) after smear layer deproteinization with chemo-mechanical caries removal agents (CRA) to enamel and dentin cavity walls in comparison with 6% NaOCl smear layer deproteinizing. METHODS: Eighty extracted bovine incisors with tapered cylindrical cavities (2.5 mm upper diameter, 1.5 mm lower diameter, 2 mm depth) at the cemento-enamel junction were randomly divided into four pre-treatment groups; no treatment (control), Papacarie (papain enzyme-based CRA), Carisolv (NaOCl-based CRA), and 6% NaOCl. After pretreatment, G-Bond Plus (GBP, one-step SEA) or Clearfil SE Bond 2 (CSE, two-step SEA) was applied to the pre-treated cavity, and then filled with a flowable resin composite (Clearfil Majesty ES Flow). Gap formations at the enamel and dentin lateral walls, and on the dentin cavity floor were investigated using swept-source optical coherence tomography (SS-OCT) after 24-h water storage at 37 °C. Deproteinizing effects of the tested agents on smear layer-covered enamel and dentin were quantified by changes in the amide:phosphate ratio using ATR-FTIR analysis. RESULTS: Papacarie significantly reduced gap formation with both self-etch adhesives at all locations, compared to the control group (p < 0.05). In contrast, increased gap formation was observed with Carisolv and NaOCl. In most groups, CSE exhibited significantly lower gap formation than GBP (p < 0.05). ATR-FTIR revealed a significant decrease in the amide:phosphate ratio for all the deproteinizing agents (p < 0.05). CONCLUSIONS: Chemo-mechanical CRAs could effectively remove the organic phase of enamel and dentin smear layer. The papain enzyme-based gel Papacarie could improve the sealing performance of the self-etch adhesives to both enamel and dentin.


Assuntos
Colagem Dentária , Camada de Esfregaço , Adesivos , Animais , Bovinos , Resinas Compostas , Cimentos Dentários , Esmalte Dentário , Dentina , Adesivos Dentinários , Teste de Materiais , Cimentos de Resina
9.
Lasers Med Sci ; 35(1): 213-219, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31342201

RESUMO

To investigate the prevalence of different patterns of cemento-enamel junction (CEJ) morphology under swept-source optical coherence tomography (SS-OCT). One hundred extracted human teeth were used consisting of incisors, premolars, and molars. Each sample was observed for every 500 µm circumferentially along CEJ and OCT images of the pattern were noted. Microscopic observations were done for the representative sample using confocal laser scanning microscope (CLSM) and transmission electron microscope (TEM). The OCT images exhibited four CEJ patterns: edge-to-edge (type I), exposed dentin (type II), cementum overlapping enamel (type III), and enamel overlapping cementum (type IV). The prevalence of CEJ patterns was further statistically considered for mesial, distal, buccal, and lingual surfaces. The real-time imaging by SS-OCT instantly determined CEJ morphology. CLSM and TEM observation revealed morphological features along CEJ, which corresponded to OCT images of CEJ anatomy. OCT results showed 56.8% of type I pattern predominantly found on proximal surfaces, followed by 36.5% of type II pattern on buccal and lingual surface, 6.4% of type III pattern, and 0.3% of type IV pattern. There was a significant difference in prevalence of CEJ patterns among different types of teeth, but there was no statistically significant difference among the four surfaces in each type of teeth. OCT is a non-invasive diagnostic tool to examine the CEJ patterns along the entire circumference. OCT observation revealed even minor dentin exposure that would need clinical and home procedures to prevent any symptoms.


Assuntos
Esmalte Dentário/anatomia & histologia , Esmalte Dentário/diagnóstico por imagem , Tomografia de Coerência Óptica , Colo do Dente/anatomia & histologia , Colo do Dente/diagnóstico por imagem , Dente Pré-Molar/anatomia & histologia , Dente Pré-Molar/diagnóstico por imagem , Humanos , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Dente Molar/anatomia & histologia , Dente Molar/diagnóstico por imagem
10.
Nihon Ronen Igakkai Zasshi ; 56(3): 323-330, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31366753

RESUMO

AIM: This study aimed to determine the perceptions among healthcare providers of the clinical need for cosmetic therapy among older adults. METHODS: A questionnaire was distributed to 190 medical staff regarding their perceptions of cosmetic therapy for older adults. The survey included questions on occupation, sex, age, cosmetic therapy in older adults, and acceptable cosmetic treatments. Nurses answered questions regarding the type of ward in which they worked. RESULTS: Completed questionnaires were collected from 121 people (mean age 33.3±9.4; men n=42). The participants included nurses (n=55), physical therapists (n=25), occupational therapists (n=15), and other occupations (n=26). Most participants believed that makeup improves the quality of life of older adults; however, many participants first became aware of the existence of cosmetic therapy through this survey. Half of the participants were interested in participating in cosmetic therapy, and a high number of women and nurses were interested. Most cosmetic treatments were acceptable to those caring for outpatients, while those caring for hospitalized patients showed low acceptance rates for treatments other than skin care. The acceptance rates tended to be particularly high for participants who worked in rehabilitation wards. CONCLUSION: Many participants believed cosmetic therapy to be effective in improving the quality of life; however, only about half of all subjects were interested in participating in cosmetic therapy. The acceptance rate of cosmetic treatments differed by work environment. This study provided valuable data contributing to the spread of cosmetic therapy.


Assuntos
Cosméticos , Adulto , Idoso , Conscientização , Feminino , Enfermagem Geriátrica , Pessoal de Saúde , Departamentos Hospitalares , Humanos , Masculino , Adulto Jovem
11.
Dent Mater J ; 38(5): 798-805, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31341147

RESUMO

The objective of this study was to determine the effect of flowable composite lining and dentin location on internal dentin fracture formation in the microtensile bond strength (MTBS) test using swept-source optical coherence tomography (SS-OCT). MTBS test beams (1.0×1.0 mm) were prepared from human superficial and deep dentin, which was bonded with a self-etch adhesive (Clearfil SE Bond) and hybrid composite resin (Clearfil AP-X), with or without flowable lining (Clearfil Majesty ES-Flow). We tested 4 groups according to placement technique (with vs. without flowable liner) and dentin (superficial vs. deep) locations. Cross-sectional 2D images of the bonded interface were obtained before and after the MTBS test. Internal dentin fracture after MTBT was observed as a bright zone in SS-OCT. Flowable lining significantly reduced internal fracture formation in dentin (p<0.05). Dentin location significantly influenced MTBS (p<0.05), and this was reduced by flowable lining usage.


Assuntos
Colagem Dentária , Adesivos Dentinários , Resinas Compostas , Estudos Transversais , Análise do Estresse Dentário , Dentina , Humanos , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Resistência à Tração
12.
Dent Mater J ; 38(5): 779-789, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31341148

RESUMO

Evaluation of gap formation at the interfaces of a two-step self-etching adhesive with/without pre-etching was performed using sweptsource optical coherence tomography (SS-OCT). Round cavities were prepared in bovine incisors at the middle (MC) and cervical (CC) thirds of the crown and the cervical third of the root (CR). Clearfil SE bond was directly applied to one group (SE) and another (PA) was pretreated with K-etchant gel. Following restoration by flowable composite resin, the teeth were thermally challenged and stored for 2 months. Interfacial gaps observed in the cross-sectional OCT images were analyzed and the bottom cavities exhibited increased gaps compared to the margin and dentin-enamel junction (DEJ). The CR site had a larger gap than at MC and CC in the SE group. DEJ separation at the MC was significantly smaller than that at CC in both groups. Therefore, gap formation depends on the cavity region, location, and bonding protocol.


Assuntos
Colagem Dentária , Adesivos Dentinários , Animais , Bovinos , Resinas Compostas , Estudos Transversais , Coroas , Preparo da Cavidade Dentária , Esmalte Dentário , Restauração Dentária Permanente , Dentina , Cimentos de Resina , Tomografia de Coerência Óptica
13.
Dent Mater J ; 38(4): 621-629, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31178547

RESUMO

The aim of this study was to investigate volumetric polymerization shrinkage (VS), using swept-source optical coherence tomography (SS-OCT), of bulk-fill composites with different light-curing strategies; immediately after light-irradiation and after 24 h, and to evaluate their regional ultimate tensile strength (UTS) at different curing depths. The immediate VS after photo-polymerization decreased when the curing light-curing time was reduced from 20 to 10 to 5 s. On the other hand, their VS values after 24 h significantly increased due to the post-cure polymerization, resulting in similar VS values at all the light-curing times. Five seconds light-curing decreased the regional UTS of resin composites after the 24 h period compared with the 10 and 20 s light-curing regimes; therefore, the remarkable progress of post-cure polymerization after light-curing for a short time would not lead to an improvement in the mechanical properties of resin composites. The influence of the light-curing time on the curing depth was dependent upon the bulk-fill composite material.


Assuntos
Resinas Compostas , Luzes de Cura Dentária , Teste de Materiais , Polimerização , Resistência à Tração
14.
Photobiomodul Photomed Laser Surg ; 37(5): 288-297, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31084561

RESUMO

Objective: The aim of this study was to examine effects of recently developed ultraviolet light-emitting diodes (UV LEDs) wavelengths on in vitro growth and gene expression of cultural periodontopathic bacteria, and on viability of experimental gingival fibroblasts. Materials and methods: Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, and Streptococcus oralis were irradiated by UV LEDs (265, 285, 310, 365, and 448 nm) at 600 mJ/cm2 and grown anaerobically in vitro. The colony forming units were counted after 1 week. Cell morphology was observed using a scanning electron microscope (SEM). Quantitative real-time polymerase chain reaction was performed to investigate gene expression changes by 310 nm irradiation. Viability of the irradiated human gingival fibroblasts was evaluated using WST-8 assay. Results: Both 265 and 285 nm resulted in the complete death of bacteria and fibroblasts, whereas 310 nm caused partial killing and suppression of bacterial growth and much less damage to the fibroblasts in vitro. Both 365 and 448 nm resulted in no significant change. SEM showed that P. gingivalis cells gradually degraded from day 2 or 3 and were severely destructed on day 5 for 265, 285, and 310 nm. The 310 nm irradiation transiently suppressed the transcripts of SOS response- and cell division-relative genes. Conclusions: Both 265 and 285 nm may induce powerful bactericidal effects and severe fibroblast phototoxicity, and 310 nm may induce partial killing or growth suppression of bacterial cells with much less fibroblast phototoxicity. UV lights may have potential for bacterial suppression, with situations dependent on wavelength, in periodontal and peri-implant therapy.


Assuntos
Aggregatibacter actinomycetemcomitans/efeitos da radiação , Fusobacterium nucleatum/efeitos da radiação , Porphyromonas gingivalis/efeitos da radiação , Prevotella intermedia/efeitos da radiação , Streptococcus oralis/efeitos da radiação , Terapia Ultravioleta , Técnicas de Cultura de Células , Fibroblastos/efeitos da radiação , Gengiva/microbiologia , Gengiva/patologia , Gengiva/efeitos da radiação , Humanos , Células-Tronco
15.
J Oral Sci ; 61(2): 221-228, 2019 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-30930355

RESUMO

Dry mouth, caused by decreased salivary gland function and/or weak salivary stimulation, can severely affect oral health in older individuals. Therefore, the aim of this study is to evaluate whether a lip trainer device and sonic toothbrush can improve salivary flow and oral wetness in older patients complaining of dry mouth. Overall, 39 subjects aged ≥60 years who had at least 20 natural teeth were randomly assigned to use a lip trainer device (group P, n = 13) or a sonic toothbrush (group S, n = 13). The subjects who did not experience oral dryness were included as controls (group C; n = 13). The unstimulated and stimulated salivary flow rates and oral wetness were measured at baseline, 1 and 6 months. The unstimulated salivary flow significantly increased in both groups at 1 and 6 months (P < 0.05). The stimulated salivary flow was also significantly increased in group P (P < 0.01) compared with the level at baseline. However, no significant difference was observed over time in group S. Oral wetness of the tongue and buccal mucosa in group P had significantly improved at 1 and 6 months (P < 0.05). Dry mouth in older individuals may be improved by using a lip trainer device or a sonic toothbrush.


Assuntos
Lábio , Xerostomia , Idoso , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Saúde Bucal , Escovação Dentária
16.
Dent Mater ; 35(4): e74-e82, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30770133

RESUMO

OBJECTIVE: The purpose of this study was to detect and investigate the association of enamel microcracks with demineralization at proximal contact areas of premolars, using 3D swept-source optical coherence tomography (SS-OCT). METHODS: Extracted maxillary and mandibular premolars (n=50 each), without any visible tooth cracks, were examined for demineralization of interproximal contact areas, using the International Caries Detection and Assessment System (ICDAS). SS-OCT was used to evaluate demineralization and detect microcracks. Demineralization progression was divided into 4 types by depth: 0 for sound enamel and Type I, II, and III for enamel demineralization penetrating into the outer third, the middle third, and the inner third of the enamel thickness, respectively. Enamel microcracks were classified according to the predominant crack pattern: Type O, no cracks; Type A, subsurface microdefects; Type B, enamel microcrack running along the direction of the enamel prism; Type C, enamel microcrack running transverse to the enamel prism direction; and Type D, a combination of patterns A, B, and C. SS-OCT findings were confirmed by confocal laser scanning microscopy observation. RESULTS: Microcracks confined within the superficial enamel in proximal contact areas were seen as bright lines on SS-OCT. There were significant positive correlations among ICDAS codes, demineralization levels, and microcrack distribution (p≤0.001). The mesial side of maxillary premolars showed significantly more demineralization (n=36) and microcracks (n=27) than that of the mandibular premolars (n=20 and n=14, respectively; p<0.001). SIGNIFICANCE: The presence of microcracks within the superficial enamel in proximal contact areas could be determined using SS-OCT, and correlated with the level of demineralization. 3D SS-OCT is a valuable diagnostic tool for comprehensive assessment of microstructural changes related to enamel demineralization and crack development.


Assuntos
Cárie Dentária , Tomografia de Coerência Óptica , Esmalte Dentário , Humanos , Microscopia Confocal
17.
Clin Oral Investig ; 23(2): 863-872, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29948272

RESUMO

OBJECTIVES: To assess the remineralization capacity of carious, non-carious, and combined white spot lesions (WSLs) using the ICDAS and SS-OCT. MATERIALS AND METHODS: This clinical trial was based on a quasi-experimental design. Forty-two healthy subjects (median age 26.6 years), who visited university hospital and had at least one WSL with an ICDAS score of 2 or 1, were recruited. The subjects chewed a non-blind sugar-free gum containing bioavailable calcium and fluoride for 3 months. The remineralization capacities of carious and non-carious 121 WSLs were assessed using ICDAS by two calibrated non-blind examiners and optical boundary depth (BD) by SS-OCT at a monthly recall. The outcome variables, transitions of ICDAS score, mean BD, and mean BD recovery rate (RR%), were statistically analyzed using the chi-square test, two way-repeated measures ANOVA, and Wilcoxon rank sum test, respectively (alpha = 0.05). RESULTS: Based on the visual inspection, OCT images at the baseline, 72 WSLs were purely carious, 20 were non-carious (developmental) lesions, while 29 were combined (carious-developmental). The responses of WSLs over time showed to be highly variable. There was a significant difference in transitions of ICDAS scores after 3 months between carious and non-carious WSLs (p < 0.05) and non-carious and combined WSLs (p < 0.05). Carious and combined WSLs underwent significant changes in the mean BD between baseline (161.8 ± 56.8 µm) and 2 months (130.7 ± 57.4 µm) or 3 months (119.1 ± 57.5 µm) (p < 0.05), while there was no significant difference between baseline (132.2 ± 26.2 µm) and 2 months (122.8 ± 24.1 µm) or 3 months (119.8 ± 22.6 µm) in non-carious WSLs (p > 0.05). There was a significant difference in mean RR% after 2 and 3 months between carious and non-carious WSLs (p < 0.05). CONCLUSIONS: The remineralization capacity of WSL was variable among the cases and subjects, and depended on the WSLs history, etiology (carious, non-carious, or combined lesion) and structure (histological pattern). CLINICAL RELEVANCE: Carious WSLs showed the highest remineralization potential.


Assuntos
Goma de Mascar , Cárie Dentária/diagnóstico por imagem , Cárie Dentária/patologia , Esmalte Dentário/patologia , Remineralização Dentária/métodos , Adulto , Feminino , Humanos , Masculino , Tomografia de Coerência Óptica
18.
J Prosthodont Res ; 63(2): 157-161, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30527704

RESUMO

PURPOSE: Elderly individuals with dry mouth wearing dentures require an appropriate denture adhesive. The purpose of this study was to evaluate the in vitro properties of a newly developed denture adhesive for patients with dry mouth and compare these with those of a currently available adhesive and oral moisturizing agent. METHODS: We developed a new gel-type denture adhesive with physical properties suitable for patients with dry mouth (DM). We subsequently performed in vitro comparisons among DM, New Poligrip (NP), and Biotene Oralbalance Gel (BT) with regard to the following properties: retention force, resistance to squeezing, and ease of removal. In accordance with the standards of the International Organization for Standardization (ISO10873:2010), the retention force was measured for dry samples (no water exposure, severe dry mouth model) and for samples exposed to water for 10min (normal model) and 1min (moderate dry mouth model). The resistance to squeezing was evaluated by pushing the samples out of syringes, while the ease of removal was evaluated by measuring the time required to wash the material from a polymethyl methacrylate plate. RESULTS: In the severe dry mouth model, DM exhibited greater retention force than did NP and BT. Moreover, the resistance to squeezing was significantly lower for DM than for NP. Both BT and DM showed better ease of removal than did NP. NP was the most difficult to wash out with water. CONCLUSIONS: Our findings suggest that the newly developed denture adhesive DM is suitable for use in patients with dry mouth.


Assuntos
Fenômenos Químicos , Cimentos Dentários/química , Materiais Dentários , Retenção de Dentadura , Prótese Total , Xerostomia , Modelos Dentários , Remoção de Dispositivo , Combinação de Medicamentos , Géis , Glucose Oxidase , Humanos , Técnicas In Vitro , Lactoperoxidase , Muramidase , Polimetil Metacrilato
19.
Lasers Med Sci ; 34(5): 901-906, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30421363

RESUMO

The objective of this study was to evaluate the bleaching effect of light sources with various wavelengths using 30% hydrogen peroxide (HP) in vitro. The hematoporphyrin-stained paper was bleached with HP and irradiated for 10 min using LED light sources with 265, 310, 365, 405, or 450 nm respectively. In control group, HP was applied for 10 min without light irradiation. The bleaching procedure was repeated two times. The L*a*b* values of the samples before bleaching and after each bleaching step were measured using a colorimeter. Color changes of specimens were then calculated and statistically analyzed. There was an interaction between light sources and time of irradiation in the color change (p < 0.05). Time and light sources significantly affected ΔE and ΔL (p < 0.05). The light source of 256 nm showed the highest bleaching effect over time followed by that of 310 nm, which were statistically different from other groups (p < 0.001). The 365 nm, 450 nm groups, and control group showed low bleaching effect visually with no significant differences in ΔE and ΔL (p > 0.05). It was concluded that the wavelengths of the light sources affected the bleaching by HP. The 310-nm light can be a potential source for bleaching.


Assuntos
Peróxido de Hidrogênio/farmacologia , Luz , Clareadores Dentários/farmacologia , Clareamento Dental , Cor , Processamento de Imagem Assistida por Computador , Papel
20.
Lasers Med Sci ; 34(5): 981-989, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30448940

RESUMO

The aim of this study was to evaluate the bactericidal effect of ultraviolet (UV) light at 265-nm (UVC) and 310-nm (UVB) wavelengths from a newly developed UV light-emitting diode (LED) device against cariogenic bacteria in vitro. Suspensions of Streptococcus mutans (S. mutans) and Streptococcus sobrinus were directly irradiated by UVB or UVC for 2.5 min or 5 min. Numbers of colonies were counted and calculated as colony forming units (CFU) per milliliter. Fluorescence microscopy (FM) and optical density measurements at 490 nm (OD490) were also taken after irradiation. In addition, the bactericidal effects of irradiation against S. mutans under 0.5 mm-thick dentin were compared using culture tests and OD490 measurements. Direct UV-LED irradiation with both UVB and UVC showed strong bactericidal effects. UVB showed superior bactericidal effect through 0.5-mm-thick dentin than did UVC, especially after demineralization. These results suggest that UVB irradiation could be utilized for the prevention and management of dental caries.


Assuntos
Cárie Dentária/microbiologia , Streptococcus mutans/efeitos da radiação , Streptococcus sobrinus/efeitos da radiação , Raios Ultravioleta , Contagem de Colônia Microbiana , Dentina/efeitos da radiação , Humanos , Viabilidade Microbiana/efeitos da radiação , Streptococcus mutans/crescimento & desenvolvimento , Streptococcus sobrinus/crescimento & desenvolvimento
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