Aim To evaluate the bottom/top hardness ratio (B/T) and the dentin bonding stability of conventional and bulk-fill resin composites in high c-factor preparations. Methods Regular conventional (Tetric N-Ceram – TNC, and Polofil Supra – PFS), regular bulk-fill (Tetric N-Ceram Bulk fill – TBF, and Admira Fusion X-tra – AFX), and low viscosity bulk-fill resin composites (Tetric N-flow – TNF, and X-tra Base – XTB) were used to restore 180 dentin conical preparations. The specimens were randomly distributed in 12 groups (n = 15) according to the resin composites and storage time-points (24 h and six months) tested. After 24 h storage, all specimens were subjected to the bottom/top hardness ratio analysis. Then, the push-out bond strength test was performed in half of the specimens and the other half were maintained for six months on water storage before testing. The failure modes were analyzed in a stereomicroscopic. The data were analyzed statistically using one- and two-way ANOVA and Tukey post-test (p <0.05). Results There were no statistically significant differences for the bottom/top hardness ratio among the resin composites (p>0.05). Regardless of the storage time-point, regular bulk-fill resin composites showed the highest bond strength values statistically (p<0.05). Only conventional resin composites showed statistically lower bond strength values at six-month storage (p<0.05). Adhesive failures were more predominant for low-viscosity bulk-fill resin composites. Conclusion Although the DoC was not affected by different materials tested, only bulk-fill resin composites did not present dentin bond strength loss after six-month of water storage.

Abstract Reducing in-office tooth bleaching sensitivity represents a challenge for professionals. Researchers have associated the block of the pain receptor TRPA1 with reducing bleaching sensitivity. However, the chemical affinity of analgesic/anti-inflammatory drugs to the TRPA1 needs to be verified. To perform a virtual screening of multiple drugs (analgesic and anti-inflammatory drugs) to verify chemical affinity for the TRPA1 receptor. The crystal structure of the TRPA1 receptor proteins was retrieved from the Protein Data Bank. The SMILES codes of the ligands were extracted from PubChem. The binding energy of the complex was obtained in ∆G - kcal/mol by AutoDock Vina© and replicated in the webservers SwissDock©, Dockthor©, and CbDock©. LigPlus© confirmed the binding sites. Codeine and dexamethasone showed regularity among all servers, even showing binding energy values of -7.9 kcal/mol for codeine and -8.1 kcal/mol for dexamethasone. Codeine and dexamethasone may be potential drugs to manage tooth bleaching sensitivity if they reach the dental pulp TRPA1 receptor.

Aim To evaluate the impact of a dual-cured adhesive system on the in situ degree of conversion (DC), bond strength (BS) and failure mode (FM) of adhesive interfaces in dentin cavities restored with a bulk-fill resin composite. Methods 4-mm-deep dentin cavities with a 3.1 C-factor were created in 68 bovine incisors (n = 17 per group). The light-cured (Scotchbond™ Universal) or the dual-cured (Adper™ Scotchbond™ Multi-purpose Plus) adhesive system was applied to the cavities, which were then restored with a bulk-fill resin composite (Filtek™ Bulk Fill). In situ DC analysis was performed by means of micro Raman spectroscopy at the top and bottom interfaces. Push-out BS was measured in a universal testing machine after 24-h or 6-month water storage. FM was determined with a stereomicroscope. Data of in situ DC and BS were analyzed by two-way analysis of variance (ANOVA) and Tukey test (p<0.05), while the FM was analyzed descriptively. Results The groups that received the dual-cured adhesive system showed statistically higher in situ DC and BS than those that received the light-cured adhesive system. Cohesive failure mode was the most frequent in all conditions. Conclusion In situ DC and BS were influenced by the curing strategies of the adhesive systems with better performance of the dual-cured material.

Resumo O objetivo deste estudo foi avaliar a influência do modo de aplicação de três sistemas adesivos universais nas propriedades físicas interfaciais de restaurações indiretas de compósito adesivamente cimentadas a cavidades dentinária. Setenta e oito incisivos inferiores bovinos foram selecionados e uma fatia de dentina (espessura: 2 mm) entre a face vestibular e a câmara pulpar foi obtida para cada dente. Cavidades cônicas foram feitas nesta superfície. As paredes internas das cavidades foram então revestidas com um gel hidrofílico, preenchidas com resina composta, e fotopolimerizados. Os conjuntos dentina/cone foram divididos em 6 grupos (n=10) de acordo com o tipo de adesivo universal (TETRI: Tetric N Bond, FUT: Futura Bond U, SBU: Single Bond Universal) e ácido na dentina (A: com condicionamento ácido; WA: sem condicionamento ácido). O condicionamento ácido e os sistemas adesivos foram aplicados na superfície da dentina. Todos os cones de resina composta foram jateados (Al2O3, 20 s) e silanizados. Após o tratamento superficial, os cones foram cimentados (RelyX Ultimate) na cavidade dentinária e fotopolimerizados. Após a termociclagem (10.000 ciclos), as amostras foram submetidas a análise de adaptação marginal (usando corante detector de carie), teste push-out (0,5 mm/min) e análise do modo de falha. Amostras adicionais foram preparadas para análise de nanoinfiltração (MEV). Os dados (MPa) foram analisados por ANOVA dois fatores e pós-teste de Tukey (5%). Os grupos em que a dentina foi condicionada por ácido apresentaram valores significativamente menores de resistência de união no teste push-out (p<0,01). O condicionamento ácido da dentina reduziu significativamente a resistência de união entre sistemas adesivos universais e dentina em procedimentos restauradores indiretos.

Abstract The purpose of this study was to evaluate the influence of the application mode of three universal adhesive systems on interfacial physical properties of indirect composite restorations adhesively cemented to dentin cavities. Seventy-eight bovine lower incisors were selected and a slice of dentin (thickness: 2 mm) between the buccal surface and pulp chamber was obtained for each tooth. Conical cavities were made on this surface. The internal walls of the cavities were then coated with a hydrophilic gel, filled with composite resin and photopolymerized. The dentin/cone sets were divided into 6 groups (n=10) according to type of universal adhesive (TETRI: Tetric N Bond, FUT: Futura Bond U, SBU: Single Bond Universal) and acid etching on dentin (A: with acid etching; WA: without acid etching). The acid etching and the adhesive systems were applied to the surface of the dentin. All composite resin cones were sandblasted (Al2O3, 20 s) and silanized. After surface treatment, the cones were cemented (RelyX Ultimate) into the dentin cavity and photopolymerized. After thermocycling (10,000 cycles), samples were submitted to marginal adaptation analysis (using caries detector dye), push-out test (0.5 mm/min), and failure mode analysis. Additional samples were prepared for nanoleakage analysis (SEM). The data (MPa) were analyzed by two-way ANOVA and Tukey’s post-test (5%). The groups in which the dentin was acid etched showed significantly lower bond strength values in the push-out test (p<0.01). Dentin acid etching significantly reduced the bond strength between universal adhesive systems and dentin in indirect restorative procedures.

Resumo O objetivo deste estudo foi avaliar a resistência de união, razão base/topo de microdureza, adaptação marginal e nanoinfiltração interfacial de resinas compostas bulk fill (BF) e tradicional (RT) de viscosidade regular.: Duas BF (Filtek Bulk Fill e Aura Bulk Fill) e duas RT (Filtek Z250XT e Aura) foram testados. Quarenta cavidades cônicas (4,8×2,8×4,0) foram preparadas em dentina bovina e restauradas com os compósitos (n=10). Depois de 24 h em água, a adaptação marginal foi avaliada por meio do corante com detector de cárie. As faces de topo e base das restaurações cônicas foram coradas por cinco segundos e a porcentagem de fendas na interface compósito/dentina foi determinada utilizando-se imagens analisadas num programa (ImageTool). A microdureza Vickers foi mensurada e a razção base/topo de microdureza (B/T) foi determinada. A resistência de união por push-out foi executada numa máquina de ensaios universal (0,5mm/min) e o padrão de fratura avaliado num estereomicroscópio (20x). Espécimes adicionais (n=3) foram confeccionados para avaliação da nanoinfiltração interfacial. Os dados foram analisados por meio de ANOVA a dois fatores e teste de Tukey (a=0,05). A porcentagem de fendas foi maior na base que no topo. A B/T da Aura Bulk Fill foi estatisticamente menor que os demais compósitos. A resistência de união por push-out foi similar entre os compósitos. As BF apresentaram menos nanoinfiltração que as RT na base das restaurações cônicas e não houve diferenças entre os materiais no topo. Conclui-se que a Filtek Bulk Fill comportou-se melhor que a Aura Bulk Fill considerando-se as propriedades analisadas.

Abstract The aim of this study was to evaluate the bond strength, bottom/top hardness ratio, marginal adaptation, and interfacial nanoleakage of regular viscosity bulk fill composites (RVBFC) and regular viscosity traditional composites (RVTC). Two RVBFC (Filtek Bulk Fill and Aura Bulk Fill) and two RVTC (Filtek Z250XT and Aura) were assessed. Forty conical cavities (4.8×2.8×4.0) were prepared in bovine dentin and restored with composites (n=10). After 24h in water, marginal adaptation was evaluated by staining with a caries detector. The top and bottom surfaces of the conical restorations were stained for five seconds and the gap percentage in the composite/dentin interface was determined using digital images on a measurement program (ImageTool). The Vickers microhardness was measured and the bottom/top microhardness ratio (B/T) was determined. Push-out bond strength test was performed in a universal testing machine (0.5mm/min) and failure modes were evaluated in a stereomicroscope (20×). Other specimens (n=3) were produced for interfacial nanoleakage evaluation. Data were analyzed using one and two-way ANOVA and Tukey’s test (α=0.05). The gap percentage was higher in the bottom compared to the top. The B/T ratio of the Aura Bulk Fill was statistically lower than other composites. Push-out bond strength were similar among composites. The RVBFC presented lower nanoleakage than the RVTC in the bottom of the conical restoration and there was no difference among the materials in the top surfaces. In conclusion, Filtek Bulk Fill performed better than Aura Bulk Fill regarding the analyzed properties.

Abstract Objectives: To study the intensity of inflammatory infiltrate and production of interleukin-1β (ll-1β), tumor necrosis factor-β (TNF-β), fibroblast growth factor-2 (FGF-2), glutathione peroxidase (GPX), and osteocalcin in response to in-office tooth bleaching in rats. Material and Methods: Twenty male Wistar rats were randomized into four groups (n=5) according to the received treatment (tooth bleaching or no treatment - control) and the period of euthanasia after treatment (24 h or 10 days). We performed tooth bleaching using a 38% hydrogen peroxide gel on maxillary and mandibular incisors. After euthanasia, incisors (20 per group) were processed for histological analysis, immunohistochemistry staining of ll-1β, TNF-β, FGF-2 and GPX and osteocalcin by immunofluorescence. We analyzed data using the Mann-Whitney and Kruskal-Wallis/Dunn tests (p<0.05). Results: The bleached groups presented statistically significant differences regarding the pulp inflammation stage compared with the control groups. Bleached teeth showed moderate/severe inflammatory infiltrate and control groups presented absent inflammatory cells or a negligible number of mononuclear cells (p<0.001) at two times (24 h and 10 days). There was strong staining for ll-1β, TNF-β, and GPX in bleached groups at 24 h and strong staining for ll-1β, TNF-β, GPX and FGF-2 at 10 days. After 10 days of tooth bleaching, the bleached group showed a statistically superior amount of osteocalcin than the other groups (p<0.01). Conclusions: Tooth bleaching with 38% hydrogen peroxide causes severe pulp inflammation, but characteristics of tissue repair after 10 days.

OBJECTIVE: To determine the safety and efficacy of a transdermal nanostructured formulation of progesterone (10%) combined with estriol (0.1%) + estradiol (0.25%) for relieving postmenopausal symptoms. METHODS: A total of 66 postmenopausal Brazilian women with climacteric symptoms of natural menopause received transdermal nanostructured formulations of progesterone and estrogens in the forearm daily for 60 months to mimic the normal ovarian secretory pattern. Confocal Raman spectroscopy of hormones in skin layers was performed. Clinical parameters, serum concentrations of estradiol and follicle-stimulating hormone, blood pressure, BI-RADS classification from bilateral mammography, and symptomatic relief were compared between baseline and 60 months post-treatment. Clinicaltrials.gov: NCT02033512. RESULTS: An improvement in climacteric symptoms was reported in 92.5% of women evaluated before and after 60 months of treatment. The serum concentrations of estradiol and follicle-stimulating hormone changed significantly (p<0.05) after treatment; the values of serum follicle-stimulating hormone decreased after 60 months from 82.04±4.9 to 57.12±4.1 IU/mL. A bilateral mammography assessment of the breasts revealed normal results in all women. No adverse health-related events were attributed to this hormone replacement therapy protocol. CONCLUSION: The nanostructured formulation is safe and effective in re-establishing optimal serum levels of estradiol and follicle-stimulating hormone and relieving the symptoms of menopause. This transdermal hormone replacement therapy may alleviate climacteric symptoms in postmenopausal women.

O objetivo deste estudo foi realizar uma revisão sistemática de estudos existentes sobre os fatores relacionados à xerostomia e/ou à hipossalivação em idosos diabéticos. Busca sistemática foi realizada nas bases de dados SciELO, Science Direct, Scopus e PubMed/Medline entre janeiro de 1992 e janeiro de 2013, coletando artigos cujo objetivo tenha sido encontrar fatores associados/relacionados à xerostomia e/ou à hipossalivação em idosos diabéticos. Cinco artigos foram selecionados, sendo quatro estudos transversais e um longitudinal. Alguns trabalhos encontraram relação entre o mau controle glicêmico e o surgimento de hipossalivação. Outros encontraram que a xerostomia foi mais frequente em pacientes que trabalhavam em ambientes não domésticos e em mulheres. Entretanto, os aspectos metodológicos utilizados pelos pesquisadores variaram bastante entre os trabalhos selecionados. Conclusões definitivas não puderam ser retiradas com base na análise dos trabalhos selecionados. Estudos longitudinais com adequado tamanho da amostra são necessários para fornecer informações mais adequadas quanto aos fatores relacionados xerostomia e hipossalivação em idosos diabéticos.

This study aimed to perform a systematic review of studies on factors related to xerostomia and/or hyposalivation in elderly patients with diabetes. SciELO, Science Direct, Scopus, and PubMed/Medline databases were searched for articles published from January 1992 to January 2013, concerned with factors associated with/related to xerostomia or hyposalivation in elderly patients with diabetes. Five articles were selected, including four transversal studies and one longitudinal study. Some of the studies found relationship between poor glycemic control and hyposalivation. Others found that xerostomia was more frequent in patients who worked in nondomestic environments and in women. However, there was considerable variation in the methods used by the researchers in the selected studies. We could not draw definitive conclusions based on our analysis of the selected studies. Longitudinal studies with appropriate sample sizes are needed to provide more complete information about the factors related to xerostomia and hyposalivation in elderly patients with diabetes.

Este trabalho avaliou o impacto de tempos aumentados de condicionamento ácido e da estratégia adesiva na resistência de união por microcisalhamento de três materiais utilizados como selantes de fóssulas e fissuras. Dois tradicionais selantes, [FluroShield, Dentsply (fotoativado) e AlphaSeal, DFL (quimicamente ativado)] e uma resina composta de baixa viscosidade (Permaflo, Ultradent) foram utilizados de acordo com diferentes tempos de condicionamento ácido (15 s e 30 s) e diferentes estratégias de união (sem aplicação de sistema adesivo, aplicação de um primer + resina hidrófoba, e aplicação apenas de uma resina hidrófoba). Fragmentos de esmalte intacto foram obtidos de incisivos bovinos e os materiais foram aplicados respeitando-se os protocolos anteriormente descritos. Após 24 h, o teste de microcisalhamento foi executado utilizando-se uma máquina de ensaio universal, com velocidade de 0,5 mm/min. O padrão de fratura foi classificado com auxílio de lupa estereoscópica. Os dados foram submetidos aos testes ANOVA a três critérios e de Tukey (α=0.05). Não houve diferenças estatisticamente significantes entre os materiais. Permaflo apresentou maior resistência de união quando o esmalte foi condicionado por 30 s apenas. O sobrecondicionamento do esmalte diminuiu a resistência de união do selante fotopolimerizável. O tratamento prévio do esmalte com primer + resina hidrófoba melhorou a performance adesiva para o AlphaSeal. Todos os materiais apresentaram valores de resistência de união estatisticamente similares em relação ao protocolo adesivo e ao tempo de condicionamento ácido. A resina composta de baixa viscosidade poderá ser utilizada como selante de fóssulas e fissuras. A aplicação de um sistema adesivo de três passos é essencial durante o selamento com selante quimicamente ativado.

This study evaluated the impact of extended etching and bonding strategies on the microshear bond strength of three sealant materials. Two pit-and-fissure sealants [FluroShield, Dentsply (light-cured) and AlphaSeal, DFL (self-cured)] and one light-cured flowable composite resin (Permaflo, Ultradent) were evaluated according to different enamel etching times (15 s or 30 s) and bonding procedures (no adhesive application, application of primer/hydrophobic resin or hydrophobic resin only). Intact enamel blocks were obtained from bovine teeth and sealed via the tested protocols. After 24 h, the microshear bond strength test was performed in a universal testing machine at a crosshead speed of 0.5 mm/min. Failure modes were classified by stereomicroscopy. Data were submitted to a three-way ANOVA and to Tukey's test (α=0.05). There was no statistically significant difference (p>0.05) among the materials. Permaflo showed higher bond strength when etched for 30 s alone. Enamel overetching decreased the bond strength of the light-cured sealant. Primer/bond previous treatment improved bond performance for AlphaSeal. In conclusion, from the tested conditions, all sealant materials presented similar bond strength values in relation to bonding protocol and etching time. The flowable composite can be used as a pit-and-fissure sealant. The use of a three-step adhesive system was essential for the self-cured sealant application.

We evaluated the influence of photoactivation method and hydrophobic resin (HR) application on the marginal and internal adaptation, hardness (KHN), and crosslink density (CLD) of a resin-based fissure sealant. Model fissures were created in bovine enamel fragments (n = 10) and sealed using one of the following protocols: no adhesive system + photoactivation of the sealant using continuous light (CL), no adhesive system + photoactivation of the sealant using the soft-start method (SS), HR + CL, or HR + SS. Marginal and internal gaps and KHN were assessed after storage in water for 24 h. The CLD was indirectly assessed by repeating the KHN measurement after 24 h of immersion in 100% ethanol. There was no difference among the samples with regard to marginal or internal adaptation. The KHN and CLD were similar for samples cured using either photoactivation method. Use of a hydrophobic resin prior to placement of fissure sealants and curing the sealant using the soft-start method may not provide any positive influence on integrity or crosslink density.

The aim of this study was to evaluate the depth of curing of 10 contemporary blue light-activated dental flowable materials at several opacities, influenced by different irradiation times using FT-IR spectroscopy. Fifty-five specimens (n = 5) with a 5-mm diameter and 1-mm thickness of translucent (Opallis Flow T), yellowed (Master Flow A2; Opallis Flow A2; Natural Flow A2; Fluroshield Yellowed), and opaque materials (Master Flow OA2; Natural Flow O; Opallis Flow OA3.5; Opallis Flow OP; Fluroshield White) were obtained at six curing times (10s, 20s, 30s, 40s, 50s, and 60s) using a high-intensity LED (Coltolux, Coltène/Whaledent). The degree of conversion (DC) (%) was obtained using the Nexus 470 FTIR Spectrometer (Nicolet Instruments, USA). The FTIR-ATR spectra for uncured and cured samples were analyzed using a ZnSe crystal. The top and bottom surfaces of the cured specimens were analyzed to obtain the depth of curing. Two-way ANOVA was used to analyze the data. The highest curing depth was obtained by Natural Flow OA2, while the lowest was shown by Master Flow OA2. The shortest curing time generated similar depths of cure in comparison with the most extensive for Opallis Flow A2 and Fluroshield Yellowed. Therefore, depth of curing, influenced by the irradiation time, was dependent on the materials. Using the Natural Flow OA2 opaque sealant and the 10-s curing time for Opallis Flow A2 and Fluroshield Yellowed may represent alternative approaches to sealing tooth fissures.

Propriedades fisicas de materiais utilizados como selantes de fossulas e fissuras estao diretamente ligadas ao seu nivel de retencao in vivo. Este trabalho objetivou avaliar a dureza Knoop (KHN) de topo e de base de, alem da razao entre a KHN de topo/base de materiais utilizados como selantes de fossulas e fissuras, como influenciadas pelo tipo de material (selante de fossulas e fissuras e resina de baixa viscosidade) e pelo tempo de fotoativacao (20 e 60 segundos). Vinte corpos-deprova foram confeccionados para os quatro grupos em analise (n=5), utilizando-se o LED Bluephase 16i. A KHN nas faces de topo e base foi obtida apos 24 h de polimerizacao e a razao entre a KHN de base/topo foi calculada. Os valores de KHN foram comparados pelos testes ANOVA/Tukey (p < 0.05). A resina de baixa viscosidade obteve maior KHN do que o selante em todas as condicoes experimentais. O selante apresentou valores de base menores que os de topo em todas as condicoes experimentais. O tempo de 60 s aumentou os valores de KHN de base das amostras da resina, bem como na razao entre a KHN de base/topo deste material. A resina de baixa viscosidade apresentou maior dureza e maior razao dureza base/topo do que o selante testado, as quais foram aumentadas com o prolongamento do tempo de exposicao radiante.

Physical properties such as surface hardness of dental materials are directly linked to their clinical behavior. The aim of this study was to investigate the influence of extended curing time on the polymerization depth of fluoride-containing materials used as pit and fissure sealants. Conventional and extended exposure times (20 and 60 seconds) were used to photoactivate a gold-standard pit and fissure sealant (Fluroshield, Dentsply) and a flowable composite (PermaFlo, Ultradent). Twenty square-shaped samples (n=5) were prepared using a LED device (Bluephase 16i, Ivoclar). The Knoop Hardness Number (KHN) was calculated for the top and bottom surface of each sample 24 hours after polymerization. Bottom/top hardness ratio (B/T KHN) was than calculated. Averages were analyzed by two-way ANOVA and Tukey test (α=0.05). The flowable composite had higher KHN than conventional pit and fissure sealant for all experimental conditions (p<0.05). The 60-second photoactivation time increased KHN at the bottom surface and B/T KHN only of composite specimens. The flowable composite had better physical properties than the pit and fissure sealant, and they were improved by extended curing time.

Este trabalho objetivou avaliar o aspecto clinico da dentina e sua microbiota na predicao da progressao de carie. A amostra foi constituida por individuos na faixa etaria de 7 a 14. O tratamento envolveu a remocao de tecido cariado pelo criterio clinico de dureza, o qual foi coletado analise microbiologica. Apos o mesmo, fez-se analise do aspecto clinico da dentina remanescente, bem como nova coleta microbiologica e restaurou- se os elementos com amalgama de prata, apos forramento com ionomero de vidro. Um ano apos, com a reabertura do dente, outra coleta microbiologica foi feita, bem como analise do aspecto clinico do tecido remanescente. O crescimento bacteriano foi analisado quantitativamente atraves de hibridizacao com sondas de DNA genomico e do metodo Checkerboard. Observou-se diferenca estatisticamente significativa entre o aspecto da dentina na linha base do estudo e um ano apos (p=0.0078). A quantidade de bacterias na linha base, em relacao a um ano depois do preparo, nao diferiu estatisticamente (p=0,37) e a microbiota predominante da dentina cariada foi composta de cocos Gram-positivos. A remocao de dentina cariada pelo criterio clinico de dureza, favorecida pela boa adaptacao da restauracao determinaram a nao progressao de carie. As poucas bacterias que ainda permaneceram na cavidade apos o preparo provavelmente tornaramse inviaveis em promover o avanco do processo carioso.

The purpose of this study was to evaluate the clinical aspect of dentine and its microbiota in predicting caries progression. The sample consisted of schoolchildren in the 7 to14 years age group. Treatment involved cavity preparation trough the clinical criterion of hardness, with the collection of carious and remnants dentine for microbiological analysis. The clinical aspect (color and consistency) of the dentine remmants was recorded and the teeth were restored using silver amalgam and glass ionomer cement as pulpal protector (baseline - BL). After 1 year the restoration was removed and after new clinical and microbiological analyses, the teeth were then restored. Microbiological samples were collected at both time-points and cultivated in sheep blood agar, in anaerobiosis for 48 hours. Bacterial growth was analyzed quantitatively. Semiquantitative and qualitative analysis of the bacteria was performed by hybridization with genomic DNA probes and the checkerboard method. A significant difference was observed between the aspect of dentine remnants at BL and at 1 year (p=0.0078). The amount of bacteria at BL and at 1 year did not differ significantly (p=0.37) and the microbiota of the carious dentine was predominantly composed of Gram-positive cocci. The removal of carious dentine based on the clinical criterion of hardness, followed by a well-adapted restoration, would determine the non-progression of caries. The few bacteria that still remained in the cavity would be no longer viable.