Effects of 3D Airway Geometry on the Airflow of Adults with Cleft Lip and Palate and Obstructive Sleep Apnea: A Functional Imaging Study.

Objective Individuals with cleft lip and palate (CLP) are at a high risk of developing obstructive sleep apnea (OSA). Hypothetically, the severity of OSA might be associated with the morphology of the upper airway (UAW) and the characteristics of the airflow. Thus, the present study aimed to assess and compare, in adults with CLP and skeletal class-III discrepancy, with or without OSA, simulations of airflow resistance and pressure according to the geometrical characteristics of the UAW and cephalometric parameters. Materials and Methods According to the results of type-I polysomnography tests, the sample ( n = 21) was allocated in 2 groups: 1) without OSA (N-OSA; n = 6); and 2) with OSA (OSA; n = 15). Cephalometric measurements were performed on the cone-beam computed tomography (CBCT) scans of the groups. After three-dimensional (3D) reconstructions, the volume (V) and minimal cross-sectional area (mCSA) of the UAW were generated. Computational fluid dynamics (CFD) simulations were used to assess key airflow characteristics. The results were presented at a significance level of 5%. Results The UAW pressure values and airway resistance did not differ between the groups, but there was a tendency for more negative pressures (26%) and greater resistance (19%) in the OSA group. Volume and mCSA showed a moderate negative correlation with resistance and pressure. The more inferior the hyoid bone, the more negative the pressures generated on the pharyngeal walls. Conclusion The position of the hyoid bone and the geometry of the UAW (V and mCSA) exerted effects on the airway-airflow resistance and pressure. However, key airflow characteristics did not differ among subjects with CLP, were they affected or not by OSA.

Three-dimensional tomographic assessment of the upper airway using 2 different imaging software programs: A comparison study.

INTRODUCTION: Several imaging software programs with different tools are available for upper airway (UAW) analysis by means of cone beam computed tomography. Because of this wide variability, this study aimed to compare the reproducibility of two of the most used software programs on UAW segmentation, that is, Dolphin Imaging (Dolphin Imaging and Management Solutions, Chatsworth, Calif) and Mimics Research (Materialise, Leuven, Belgium). METHODS: The sample consisted of 50 scans of adult subjects with Class III malocclusion; pharyngeal volume and minimal cross-sectional area (mCSA) were assessed twice by 2 experienced evaluators using both software programs. Intra- and intersoftware and/or evaluator agreement were calculated using the intraclass correlation coefficient (ICC). Bland-Altman analysis was used to visualize the intersoftware and interevaluator agreement. RESULTS: Using Mimics Research and Dolphin Imaging, the respective mean values of volume (cm3) were 27.1 ± 8.4 and 24.7 ± 8.1 (P < 0.05) and of mCSA (mm2) were 167.8 ± 95.5 and 176.5 ± 102.3 (P < 0.05). Although differences between software packages were observed on both the analyzed variables, the results showed a high intersoftware agreement, with ICC of 0.87 (volume) and 0.97 (mCSA) and mean bias of 24.6 (volume) and -8.8 (mCSA). A high intrasoftware agreement was also observed, with values varying from 0.83 to 0.99. Excellent intra- and interevaluator agreement was also obtained, with ICC values from 0.93 to 0.99. CONCLUSIONS: Dolphin Imaging and Mimics Research individually provide highly reproducible results, with clinically acceptable agreement between them for UAW segmentation, providing consistent values for volume and mCSA.

Reduced pharyngeal dimensions and obstructive sleep apnea in adults with cleft lip/palate and Class III malocclusion.

Objective: To three-dimensionally evaluate the upper airway of individuals with cleft lip and palate (CLP) and Class III malocclusion and the occurrence of obstructive sleep apnea (OSA).Methods: Twenty-one CLP individuals with Class III malocclusion, 20-29 years of age, who underwent computed tomography for orthognathic surgery planning, were prospectively evaluated. All participants underwent polysomnography, and the apnea-hypopnea index ≥ 5 events/hour was considered indicative of OSA. The total upper airway and its subdivisions volumes, as well as the minimum pharyngeal cross-sectional area (CSA), were assessed using Mimics software.Results: Among the 21 individuals analyzed, 6 (29%) presented with OSA. The total upper airway and the oropharynx mean volumes were significantly decreased in subjects with OSA when compared to individuals without OSA. Mean CSA was not statistically different between groups.Conclusion: CLP individuals with Class III malocclusion and OSA have an upper airway significantly smaller than individuals without OSA.

Antimicrobial activity of ozone and NaF-chlorhexidine on early childhood caries.

An early childhood carie (ECC) is an extremely destructive form of tooth decay. The aim of this study was to investigate the action of ozone (O3), and the association of sodium fluoride (NaF) with chlorhexidine (CHX) on bacteria related to ECC. Overnight culture of the bacteria was performed. On exponential phase the suspension was adjusted (101-108 CFU/mL). A drop (10µL) of each concentration of bacteria was applied on sheep blood agar plates and treated with O3 (2, 20, 200, and 2,000 ppm); after 18 hours, recovery analysis of CFU verified the reduction of bacterial activity. For NaF-CHX, sterile 96-well plates were prepared and divided into groups: G1 (150 µL TSB); G2 (20 µL of bacteria + 25 µL CHX + 25 µL NaF); and G3 (150 µL TSB + 20 µL of bacteria + 50 µL water). The plates were verified by analysis of the optical density (0, 12, 14, 16, and 18 hours). The data from O3 test were submitted to ANOVA and Tukey's test (p < 0.05). For the data from NaF-CHX, the ANOVA 2-way and Bonferroni's test (p < 0.05) were used. The number of CFU/mL showed death > 3log10 (99.9%) for all bacteria (ozone ≥ 20ppm), while the combination of NaF-CHX was more effective (p < 0.001) compared to each substance tested alone and the control group. The antimicrobial agents tested were able to inhibit all bacteria tested; O3 seemed to be a good alternative for controlling progression of carious lesions, while the association of NaF-CHX showed to be a good antimicrobial with easy and inexpensive application.

Antimicrobial activity of ozone and NaF-chlorhexidine on early childhood caries

Abstract An early childhood carie (ECC) is an extremely destructive form of tooth decay. The aim of this study was to investigate the action of ozone (O3), and the association of sodium fluoride (NaF) with chlorhexidine (CHX) on bacteria related to ECC. Overnight culture of the bacteria was performed. On exponential phase the suspension was adjusted (101-108 CFU/mL). A drop (10μL) of each concentration of bacteria was applied on sheep blood agar plates and treated with O3 (2, 20, 200, and 2,000 ppm); after 18 hours, recovery analysis of CFU verified the reduction of bacterial activity. For NaF-CHX, sterile 96-well plates were prepared and divided into groups: G1 (150 µL TSB); G2 (20 µL of bacteria + 25 µL CHX + 25 µL NaF); and G3 (150 µL TSB + 20 µL of bacteria + 50 µL water). The plates were verified by analysis of the optical density (0, 12, 14, 16, and 18 hours). The data from O3 test were submitted to ANOVA and Tukey’s test (p < 0.05). For the data from NaF-CHX, the ANOVA 2-way and Bonferroni’s test (p < 0.05) were used. The number of CFU/mL showed death > 3log10 (99.9%) for all bacteria (ozone ≥ 20ppm), while the combination of NaF-CHX was more effective (p < 0.001) compared to each substance tested alone and the control group. The antimicrobial agents tested were able to inhibit all bacteria tested; O3 seemed to be a good alternative for controlling progression of carious lesions, while the association of NaF-CHX showed to be a good antimicrobial with easy and inexpensive application.

Diabetes mellitus and drug abuse during pregnancy and the risk for orofacial clefts and related abnormalities.

OBJECTIVE: to assessed the prevalence of diabetes mellitus (DM) and drug abuse in mothers of children with orofacial clefts (OFC). METHODS: 325 women who had children (0-3y) with clefts were interviewed. Data regarding type of diabetes, use of legal/illegal drugs during pregnancy, waist girth and fasting blood sugar at the first prenatal consult were collected. RESULTS: twenty seven percent of the women had DM, out of these, 89% had gestational DM, 5,5% type 1 DM and 5,5% type 2 DM. The prevalence of DM in mothers of children with OFC was 27%, it is significantly higher than the average Brazilian population which is 7.6% (p<0.01) (OR=4.5, 95%CI=3.5-5.8). Regarding drug abuse during pregnancy, 32% of the mothers used drugs and a significant positive correlation was observed between drug abuse and the occurrence of clefts and other craniofacial anomalies (p=0.028) (OR=2.87; 95%CI=1.1-7.4). CONCLUSIONS: DM and drug abuse during pregnancy increases the risk for OFC and related anomalies and early diagnosis of DM and prevention of drug abuse, especially in pregnant women, should be emphasized.

Micro-CT evaluation of the radioprotective effect of resveratrol on the mandibular incisors of irradiated rats.

The purpose of this study was to perform a microcomputed tomographic evaluation of the radioprotective effect of resveratrol on the volume of mandibular incisors of irradiated rats. A second aim was to make a quantitative assessment of the effect of x-ray exposure on these dental tissues. Twenty adult male rats were divided into four groups: control, irradiated control, resveratrol, and irradiated resveratrol. The resveratrol groups received 100 mg/kg of resveratrol, whereas the irradiated groups were exposed to 15 Gy of irradiation. The animals were sacrificed 30 days after the irradiation procedure, and their mandibles were removed and scanned in a microcomputed tomography unit. The images were loaded into Mimics software to allow segmentation of the mandibular incisor and assessment of its volume. The results were compared by One-way ANOVA and Tukey's post hoc test, considering a 5% significance level. The irradiated groups showed significantly diminished volumes of the evaluated teeth, as compared with the control group (p < 0.05). The resveratrol group presented higher values than those of the irradiated groups, and volumes similar to those of the control group. High radiation doses significantly affected tooth formation, resulting in alterations in the dental structure, and thus lower volumes. Moreover, resveratrol showed no effective radioprotective impact on dental tissues. Future studies are needed to evaluate different concentrations of this substance, in an endeavor to verify its potential as a radioprotector for these dental tissues.

Diabetes mellitus and drug abuse during pregnancy and the risk for orofacial clefts and related abnormalities / La diabetes mellitus, el abuso de drogas durante el embarazo y el riesgo de malformaciones craneofaciales y anomalías relacionadas / Diabetes mellitus e uso de drogas durante a gravidez e o risco de fissuras orofaciais e anomalias relacionadas

Abstract Objective: to assessed the prevalence of diabetes mellitus (DM) and drug abuse in mothers of children with orofacial clefts (OFC). Methods: 325 women who had children (0-3y) with clefts were interviewed. Data regarding type of diabetes, use of legal/illegal drugs during pregnancy, waist girth and fasting blood sugar at the first prenatal consult were collected. Results: twenty seven percent of the women had DM, out of these, 89% had gestational DM, 5,5% type 1 DM and 5,5% type 2 DM. The prevalence of DM in mothers of children with OFC was 27%, it is significantly higher than the average Brazilian population which is 7.6% (p<0.01) (OR=4.5, 95%CI=3.5-5.8). Regarding drug abuse during pregnancy, 32% of the mothers used drugs and a significant positive correlation was observed between drug abuse and the occurrence of clefts and other craniofacial anomalies (p=0.028) (OR=2.87; 95%CI=1.1-7.4). Conclusions: DM and drug abuse during pregnancy increases the risk for OFC and related anomalies and early diagnosis of DM and prevention of drug abuse, especially in pregnant women, should be emphasized.

Resumen Objetivos: esta investigación estableció la prevalencia de diabetes mellitus (DM) y el abuso de drogas en madres de niños con malformaciones creaneofaciales (MCF). Métodos: 325 mujeres que tuvieron hijos (0-3 años) con malformaciones fueron entrevistadas. Se obtuvieron datos referentes a: tipo de diabetes; uso de drogas lícitas o ilícitas durante el embarazo; circunferencia de la cintura; y, glucemia en ayunas en la primera consulta prenatal. Resultados: el veintisiete por ciento de las mujeres tenían DM. Entre estas, el 89% tuvieron DM gestacional, el 5,5% DM tipo 1 y el 5,5% DM tipo 2. La prevalencia de DM en madres de hijos con MCF fue de 27%. Esto es significativamente más alto que el promedio de la población brasileña afectada por esa enfermedad, que es de 7,6% (p<0.01) (OR=4,5, 95%IC=3,5-5,8). Observando el abuso de drogas durante el embarazo, el 32% de las madres había utilizado drogas y una correlación positiva significativa fue observada entre el abuso de drogas y la ocurrencia de hendiduras y otras malformaciones craneofaciales (p=0,028) (OR=2,87; 95%IC=1,1-7,4). Conclusiones: la DM y el abuso de drogas durante el embarazo aumentan el riesgo de MCF y de anomalías relacionadas; se enfatiza la importancia del diagnóstico precoz de DM y la prevención del abuso de drogas, especialmente entre las mujeres embarazadas.

Resumo Objetivos: avaliar a prevalência de diabetes mellitus (DM) e o uso de drogas em mães de crianças com fissuras orofaciais (FOF). Método: 325 mulheres que tiveram filhos (0-3 anos) com fissuras foram entrevistadas. Os dados referentes tipo de diabetes, uso de drogas lícitas / ilícitas durante a gravidez, circunferência abdominal e glicemia em jejum na primeira consulta pré-natal foram coletados. Resultados: vinte e sete por cento das mulheres tinham DM. Destes, 89% tinham DM gestacional, 5,5% DM tipo 1 e 5,5% DM tipo 2. A prevalência de DM em mães de crianças com FOF foi de 27%, significativamente mais elevado que a média da população brasileira que é de 7,6% (p <0,01) (OR = 4,5, IC de 95% = 3,5-5,8). Com relação ao uso de drogas, 32% das mães eram usuárias drogas durante a gravidez e uma correlação positiva foi observada entre o uso de drogas e a ocorrência de FOF e anomalias relacionadas (p = 0,028) (OR = 2,87; IC95% = 1,1-7,4). Conclusões: DM e uso de drogas durante a gravidez aumentam o risco de FOF e anomalias relacionadas e o diagnóstico precoce de DM e a prevenção do uso de drogas, especialmente em mulheres grávidas, devem ser enfatizados.

Micro-CT evaluation of the radioprotective effect of resveratrol on the mandibular incisors of irradiated rats

Abstract The purpose of this study was to perform a microcomputed tomographic evaluation of the radioprotective effect of resveratrol on the volume of mandibular incisors of irradiated rats. A second aim was to make a quantitative assessment of the effect of x-ray exposure on these dental tissues. Twenty adult male rats were divided into four groups: control, irradiated control, resveratrol, and irradiated resveratrol. The resveratrol groups received 100 mg/kg of resveratrol, whereas the irradiated groups were exposed to 15 Gy of irradiation. The animals were sacrificed 30 days after the irradiation procedure, and their mandibles were removed and scanned in a microcomputed tomography unit. The images were loaded into Mimics software to allow segmentation of the mandibular incisor and assessment of its volume. The results were compared by One-way ANOVA and Tukey's post hoc test, considering a 5% significance level. The irradiated groups showed significantly diminished volumes of the evaluated teeth, as compared with the control group (p < 0.05). The resveratrol group presented higher values than those of the irradiated groups, and volumes similar to those of the control group. High radiation doses significantly affected tooth formation, resulting in alterations in the dental structure, and thus lower volumes. Moreover, resveratrol showed no effective radioprotective impact on dental tissues. Future studies are needed to evaluate different concentrations of this substance, in an endeavor to verify its potential as a radioprotector for these dental tissues.

Clinical evaluation of desensitizing treatments for cervical dentin hypersensitivity.

The aim of this study was to compare different treatments for dentin hypersensitivity in a 6-month follow-up. One hundred and one teeth exhibiting non carious cervical lesions were selected. The assessment method used to quantify sensitivity was the cold air syringe, recorded by the visual analogue scale (VAS), prior to treatment (baseline), immediately after topical treatment, after 1 week, 1, 3 and 6 months. Teeth were randomly assigned to five groups (n = 20): G1: Gluma Desensitizer (GD); G2: Seal& (SP); G3: Oxa-gel (OG); G4: Fluoride (F); G5: Low intensity laser-LILT (660 nm/3.8 J/cm(2)/15 mW). Analysis was based on the non-parametric Kruskal-Wallis test that demonstrated statistical differences immediately after the treatment (p = 0.0165). To observe the individual effects of each treatment, data was submitted to Friedman test. It was observed that GD and SP showed immediate effect after application. Reduction in the pain level throughout the six-month follow-up was also observed. In contrast, LILT presented a gradual reduction of hypersensitivity. OG and F showed effects as of the first and third month respectively. It can be concluded that, after the 6-month clinical evaluation, all therapies showed lower VAS sensitivity values compared with baseline, independently of their different modes of action.

Efeito da ciclagem térmica na microinfiltração e microtração de restaurações de resina composta / Effect of thermal cycling on microleakage and µTBS of resin-composite restorations

O objetivo deste estudo foi avaliar a microinfiltração e a resistência de união à dentina por meio do teste de microtração em restaurações classe III, usando dois sistemas adesivos - o autocondicionante Clearfil SE Bond®/ Kuraray (SE) e o sistema de condicionamento ácido total Single Bond®/3MEspe (SB) -, submetidas (C) ou não à ciclagem térmica (NC). Foram preparadas duzentas cavidades classe III em incisivos bovinos, divididas em quatro grupos: G1:SB/NC; G2:SB/C; G3:SE/NC; G4:SE/C. Após restaurados, os G1 e G3 foram imersos em solução corante e os dentes, levados à cortadora metalográfica, sendo as restaurações seccionadas no sentido V-L em fatias de 0,7 a 0,8 mm. Essas secções foram, primeiramente, avaliadas quanto à penetração de corante e, em seguida, submetidas ao teste de microtração (área adesiva: 1 mm2), confeccionando-se espécimes em forma de "hourglass". Para os G2 e G4 as amostras foram submetidas a 2000 ciclos térmicos (5-55 ºC) e, após, sofreram os mesmos procedimentos descritos para os G1 e G3. Quanto à microinfilitração, os resultados foram analisados pelo teste de Kruskal-Wallis (p < 0,05), não demonstrando diferença estatisticamente significativa entre os grupos. Os dados de microtração (MPa) foram submetidos ao teste Anova dois fatores e Tukey (p < 0,05): G1:18,80a; G2:19,78a; G3:13,29c; G4:6,23b. Independentemente da ciclagem térmica, os dois adesivos apresentaram a mesma permissibilidade de microinfiltração. O desafio térmico influenciou negativamente na força de adesão do autocondicionante SE, mas não interferiu nos valores do SB.

The aim of this study was to evaluate the microleakageand μTBS of class III composite resin restoration using two bonding systems – the self etching primer Clearfil SE Bond/Kuraray (SE) and the one-bottle Single Bond/3MEspe (SB) subjected (C) or not (NC) to thermal cycles. 200 box-type class III cavities were prepared on surfaces of bovine incisors and divided into 4 groups: G1:SB/NC; G2:SB/C; G3:SE/NC; G4:SE/C. After the restorative procedures, G1 and G3 were immersed in a dye solution and the restorations were sectioned perpendicular to the cervical margin interface into 0.7± 0.2 mm thick slabs. These sections were first evaluated according to dye penetration and then the slabs were further trimmed at the interface to produce samples with a hourglass shape (cross-sectional surfacearea of 1mm2) to μTBS test evaluation. The samples ofG2 and G4 were thermocycled (2.000 cycles, 5-55 oC) and then subjected to the same procedures described for G1 and G3. The microleakage results were analyzed by the de Kruskal-Wallis (p < 0.05) test, and no differences were observed among groups. The μTBS means were analyzed by the Anova 2 way and Tukey test:G1:18.80a; G2:19.78a; G3:13.29c; G4:6.23b. Regardless the thermal cycles, both adhesive systems present the same microleakage results. However, for SE thermal cycling had adversely affected the bond strength values,but for SB no differences were observed.

Influence of different exposure time required to stabilize hardness values of composite resin restorations.

AIM: The purpose of this study was to evaluate if Knoop hardness values (KHN) for top and bottom surfaces of resin composite materials can reach a plateau within a clinically acceptable photoactivation time. METHODS AND MATERIALS: Four light-curing units (LCUs) were evaluated in this study (n=5): QTH (Optilux501: 550 mW/cm2) and LEDs (FreeLight2: 1100 mW/cm2; UltraLume5: 900 mW/cm2; and Radii: 750 mW/cm2). Composite resin discs (4 mm x 2 mm) of Heliomolar (Ivoclar/Vivadent) and Herculite XRV (Kerr) were tested using five photoactivation times (20, 40, 60, 80, and 100 seconds). KHN were obtained for each test specimen and comparisons between LCUs, depths, and photoactivation times were analyzed using two-way analysis of variance (ANOVA) and polynomial regression analysis. RESULTS: Data for Heliomolar discs using linear regression found a relationship between the independent variables KHN and time with the Optilux501 at the top and bottom surfaces (r2=0.68/ r2=0.66). Radii presented a linear regression at the top surface (r2=0.75) and a quadratic regression at the bottom (r2=0.94). A quadratic regression was also detected for UltraLume5 and FreeLight2 at both top (r2=0.84/ r2=0.94) and bottom surfaces (r2=0.97/ r2=0.90), respectively, reaching a plateau at 80 seconds in all cases. For Herculite XRV, a quadratic regression was observed for all LCUs at the top and bottom surfaces and 80 seconds irradiation time was needed to reach a plateau in KHN. CONCLUSION: There is a specific, but not clinically acceptable, photoactivation time that KHN at both top and bottom surfaces can reach a plateau and is dependent on LCUs and the resin-composite tested. CLINICAL SIGNIFICANCE: The LCUs and the resin-composite formulation affected the exposure time required to stabilize hardness values. The overall performance of LED LCUs was better than the QTH LCU regardless of the material evaluated.

Clinical evaluation of desensitizing treatments for cervical dentin hypersensitivity

The aim of this study was to compare different treatments for dentin hypersensitivity in a 6-month follow-up. One hundred and one teeth exhibiting non carious cervical lesions were selected. The assessment method used to quantify sensitivity was the cold air syringe, recorded by the visual analogue scale (VAS), prior to treatment (baseline), immediately after topical treatment, after 1 week, 1, 3 and 6 months. Teeth were randomly assigned to five groups (n = 20): G1: Gluma Desensitizer (GD); G2: Seal&Protect (SP); G3: Oxa-gel (OG); G4: Fluoride (F); G5: Low intensity laser-LILT (660 nm/3.8 J/cm²/15 mW). Analysis was based on the non-parametric Kruskal-Wallis test that demonstrated statistical differences immediately after the treatment (p = 0.0165). To observe the individual effects of each treatment, data was submitted to Friedman test. It was observed that GD and SP showed immediate effect after application. Reduction in the pain level throughout the six-month follow-up was also observed. In contrast, LILT presented a gradual reduction of hypersensitivity. OG and F showed effects as of the first and third month respectively. It can be concluded that, after the 6-month clinical evaluation, all therapies showed lower VAS sensitivity values compared with baseline, independently of their different modes of action.

Variability of shear and microtensile bond strength tests to enamel and dentin / Variabilidade de testes de cisalhamento e microtração ao esmalte e à dentina

Purpose: This study aimed to provide guidelines about the coefficient of variation (CV) of shear (SBS) and microtensile (µTBS) bond strength to enamel and dentin. Methods: A search of the English language peer-reviewed literature was conducted using the PubMed database from 2000 to 2009. Only bond strength studies (SBS and µTBS) that have tested both enamel and dentin substrates were selected. The following information was gathered from the 103 papers selected: groups mean and standard deviation (SD), repetition number, and type of statistical analysis. The CV of each study was calculated by using its mean and SD values, the normality of shear and microtensile CV was analyzed using Shapiro-Wilk test, and a CV classification was established for each variable. Results: According to the CV classification proposed, values below 10.3% and 11.3% could be considered low for shear bond strength to enamel and dentin, respectively; and values below 15.4% to enamel and 16.4% to dentin could be considered low for the microtensile test. Values higher than 46.8% and 62.1% (shear bond strength to enamel and dentin) and 45.9% and 45.5% (microtensile bond strength to enamel and dentin) showed a very high variability. Conclusion: Such classification can be useful for future experiments on adhesive materials to estimate statistical power and data precision.

Objetivo: Este estudo se propôs a fornecer diretrizes sobre o coeficiente de variação (CV) de ensaios de resistência ao cisalhamento (SBS) e à microtração (µTBS) em esmalte e dentina.Metodologia: Uma busca de artigos publicados de 2000 a 2009 foi realizada na base de dados PubMed. Apenas estudos (SBS e µTBS) que testaram esmalte e dentina foram considerados elegíveis. As seguintes informações foram coletadas dos 103 artigos selecionados: média e desvio-padrão (DP) dos grupos, número de repetições e análise estatística. O CV de cada estudo foi calculado utilizando-se média e DP, a normalidade dos CV de cada teste foi analisada pelo teste de Shapiro-Wilk e classificações para os CV foram estabelecidas. Resultados: De acordo com a classificação proposta, valores menores que 10,3% e 11,3% são baixos para estudos de cisalhamento ao esmalte e dentina, respectivamente. Para estudos de microtração, baixa variabilidade é obtida com CV menores que 15,4% (esmalte) e 16,4% (dentina). Experimentos com CV maiores que 46,8% e 62,1% (cisalhamento no esmalte e dentina) e 45,9% e 45,5% (microtração no esmalte e na dentina) apresentam variabilidade muito alta. Conclusão: Esta classificação pode ser útil para futuros experimentos em Odontologia adesiva para estimar o poder estatístico dos testes e a precisão dos dados.

Effect of long-term water storage on etch-and-rinse and self-etching resin-dentin bond strengths.

This study sought to evaluate the long-term bond strength of etch-and-rinse and self-etch adhesive systems to dentin after one year of water storage. Crown fragments from the buccal surface of extracted bovine incisors were ground flat to expose dentin surfaces. Four etch-and-rinse and two self-etch bonding agents were used according to manufacturers' instructions. Bonded specimens were stored in water for either 24 hours or one year at 37 delete C. After elapsed storage times, specimens were tested for shear bond strength (SBS) at 0.5 mm/min. Data were analyzed by ANOVA and Tukey's tests (p < 0.05). Both evaluated factors (adhesive system and storage time) and their interactions were statistically significant. Single Bond produced the highest SBS regardless of the water degradation period. One-year water storage reduced the SBS of Prime & Bond NT and One-Up Bond F significantly; the other adhesives performed similarly. Long-term bond strengths of etch-and-rinse and self-etch adhesive systems are susceptible to hygroscopic and hydrolytic effects to varying extents, depending on their chemistry and structure. The presence of monomers with different properties might induce preferential degradation of specific adhesive polymer systems.

Histomorphologic characterization and bond strength evaluation of caries-affected dentin/resin interfaces: effects of long-term water exposure.

OBJECTIVES: To evaluate the longevity of sound (SD) and caries-affected dentin (CAD) bonds made with etch-and-rinse and self-etching adhesives after a 6-month water-storage period, using bond strength and morphological evaluations. METHODS: Extracted human molars with coronal carious lesions were selected. Flat surfaces of CAD surrounded by SD were bonded with etch-and-rinse (Adper Scotchbond 1) or with self-etching (Clearfil Protect Bond and AdheSE) adhesives. Trimmed resin-dentin bonded interfaces (1mm2) were stored in distilled water for 24h or 6 months and subjected to microtensile bond strength (microTBS) evaluation. The quality of the dentin beneath fractured specimens was measured by Knoop microhardness (KHN). ANOVA and multiple comparisons tests were used (P<0.05). Fractographic analysis and interfacial nanoleakage evaluation were performed by scanning electron microscopy (SEM). Resin-dentin bonded sections (10microm thick) were stained with Masson's trichrome and examined using light microscopy. Collagen exposure and adhesive penetration were examined qualitatively. RESULTS: microTBS to SD was significantly higher than that to CAD for all bonding agents. Bonds made with AdheSE were weaker than the other adhesives after 6-months storage regardless of the dentin substrate. CAD bonded specimens presented a significant muTBS decrease over time. Lower KHN was recorded in CAD compared to SD. An increase in the exposed collagen zone and a decrease in the quality of the adhesive infiltration were observed in CAD interfaces. SIGNIFICANCE: CAD bonded interfaces are more prone to hydrolytic degradation than SD bonds. Additionally, as compared to SD, there were remarkable differences in depth of demineralization, adhesive infiltration and interfacial bond strength with CAD.

In vitro microTBS of one-bottle adhesive systems: sound versus artificially-created caries-affected dentin.

This in vitro study aimed to evaluate a pH-cycling model for simulation of caries-affected dentin (CAD) surfaces, by comparing the bond strength of etch-and-rinse adhesive systems on sound and artificially-created CAD. Dentin substrates with different mineral contents and morphological patterns were created by submitting buccal bovine dentin to the following treatments: (1) immersion in artificial saliva during the experimental period (sound dentin, SD), or (2) induction to a CAD condition by means of a dynamic pH-cycling model (8 cycles, demineralization for 3 h followed by mineralization for 45 h). The bond strength of Excite or Prime and Bond NT adhesive systems was assessed using the microtensile bond strength (microTBS) test. Dentin microhardness was determined by cross-sectional Knoop evaluations. Resin-dentin morphology after the treatments was examined by scanning electron microscopy. SD produced significantly higher microTBS than CAD for both adhesives evaluated, without differences between materials. CAD exhibited lower microhardness than SD. Morphological analysis showed marked distinctions between SD and CAD bonded interfaces. Under the conditions of this study, differences in morphological pattern and dentin mineral content may help to explain resin-dentin bond strengths. The proposed pH-cycling model may be a suitable method to simulate CAD surfaces for bonding evaluations.

Effect of light curing units on marginal adaptation and hardness of Class II composite resin restorations.

AIMS: The aim of this study was to test the influence of different curing protocols on dentin marginal adaptation and the hardness of two composites. METHODS AND MATERIALS: Three light-curing-units (LCUs): Quartz-Tungsten-Halogen (QTH: 541 mW/cm2), Argon-Ion-Laser (AL: 277 mW/cm2), and Plasma-Arc-Curing (PAC: 1818 mW/cm2) and two composites FiltekZ250 (F) and Tetric Ceram HB (TC) were tested. Sixty standardized "vertical-slot-Class II-cavities" were prepared at the mesial surface of bovine incisors and divided into six groups (n=10). Composites were placed using the Single Bond adhesive system and cured in 2 mm increments according to the manufacturers' instructions. After polishing, epoxy replicas were processed for scanning electron microscopy (SEM) marginal adaptation analysis at 500x magnification. The specimens were then sectioned transversally to the dental long axis, embedded in polyester resin, then polished and submitted to the Knoop hardness test at gingival and occlusal portions of the restoration. Data were analyzed using two-way analysis of variance (ANOVA) and Tukey's test (p=0.05). RESULTS: The gap margins ranged between 4.3 to 5.8 microm, and no statistically significant differences were revealed in marginal adaptation for LCUs or for composites (p>0.05). Location influenced hardness (p=0.01). The occlusal portion presented significantly higher KHN than the gingival portion for all composite-LCU combinations. Regardless of the LCU used, TC produced statistically significant lower hardness values (ranging between 82.8 to 110.7 KHN) than F (ranging between 105.9 to 117.3 KHN). CONCLUSIONS: Hardness and gap formation were not dependent on the LCUs tested in this study. Different resin composite was found to be a significant factor with regards to hardness but not gap formation.

Effect of photoactivation systems and resin composites on the microleakage of esthetic restorations.

AIM: The aim of this study was to evaluate the influence of four photoactivation systems [quartz tungsten halogen (QTH), light-emitting diode (LED), argon ion laser (AL), and plasma arc curing PAC)] on cementum/dentin and enamel microleakage of Class II restorations using a microhybrid [Z250-3M ESPE] and two packable composites [(SureFil-Dentsply and Tetric Ceram HB-Ivoclair/Vivadent]. METHODS AND MATERIALS: Three hundred sixty "vertical-slot Class II cavities" were prepared at the mesial surface of bovine incisors using a 245 carbide bur in a highspeed handpiece. Specimens were divided into twelve groups (composite-photoactivation systems). Half of the specimens had the gingival margin placed in enamel (n=15) and the other half in cementum/dentin (n=15). Composites were inserted and cured in 2 mm increments according to manufacturers' recommended exposure times. After polishing, the samples were immersed in 2% methylene blue solution, sectioned, and evaluated at the gingival margins. Data were submitted to statistical analysis using the Kruskal-Wallis and Mann-Whitney tests. RESULTS: No significant differences were found among the photoactivation systems and among resin composites (p>0.05). Microleakage was not significantly affected by location (enamel vs. cementum/dentin, p>0.05). These findings suggested neither the photoactivation systems nor the resin composite types might have an effect on the microleakage at gingival margins Class II cavities.

2-year Clinical evaluation of sodium hypochlorite treatment in the restoration of non-carious cervical lesions: a pilot study.

This pilot study evaluated the effect of removing acid-etch-exposed dentin collagen on the clinical performance of composite restorations of noncarious cervical lesions placed using 2 different adhesive systems. Fifty-six restorations were placed in 14 subjects, each subject receiving at least 4 restorations. No cavity preparation or mechanical retention form was used. The variables tested were: 1) dentin treatment prior to application of the adhesive (acid-etch only vs acid-etch and collagen removal) and 2) type of adhesive (acetone- vs ethanol-based). For the acid-etch only groups, enamel and dentin were etched with 37% phosphoric acid for 15 seconds, rinsed and blot dried. Prime & Bond 2.1 (Dentsply Caulk) or Single Bond (3M ESPE) was applied and light-cured according to the manufacturer's instructions. For the acid-etch and collagen removal groups, the enamel and dentin were etched and rinsed in the same manner and a 10% sodium hypochlorite (NaOCl) solution was applied for 60 seconds and rinsed before adhesive application. Filtek Z-250 (3M ESPE) was applied to all specimens and light-cured according to the manufacturer's instructions, and the restorations were finished and polished immediately. The restorations were evaluated for pre- and post-operative sensitivity, retention, marginal staining and secondary caries at baseline, 12 and 24 months after placement, using modified USPHS criteria. Data were analyzed using the Kruskal-Wallis and Wilcoxon statistical tests (p=0.05). At 24 months, the retention rates for Prime & Bond 2.1 with and without NaOCl pretreatment were 80% and 63%, respectively. The corresponding retention rates for Single Bond were 70% and 90%. Marginal staining was minimal. Statistical analyses revealed no significant differences at any time interval between groups for retention or marginal staining. No post-operative sensitivity or secondary caries was detected during the study.