Using self-etch adhesive agents with pit and fissure sealants. In vitro analysis of shear bond strength, adhesive remnant index and enamel etching patterns.

PURPOSE: The aim of this study was to evaluate in vitro, the shear bond strength (SBS) and adhesive remnant index (ARI) of pit and fissure sealants (PFS) after enamel conditioning with different new-generation self-etching (SE) agents; additionally, enamel etching patterns were assessed. METHODS: Healthy unerupted third molars surgically removed for therapeutic reasons (n = 25p/g), were randomly assigned to six groups. Conventional etching (CE) or SE was applied prior to pit and fissure sealants bonding. Enamel conditioned surfaces were evaluated by SEM at × 500, × 1000, and × 2000 magnification to determine etching patterns. Subsequently, 25 PFS blocks (3 × 2 × 1.5 mm) p/g were bonded to enamel surface. Samples were stored in water at 37 °C for 24 h, previous to SBS and ARI test. One-way ANOVA and Tamhane statistic tests were used for SBS; while Mann-Whitney U and Kruskal-Wallis were employed for ARI (p ≤ 0.05). RESULTS: For SBS test, CE_PFS_3M and SE1_PFS_Shofu groups showed the lowest values (8.74 ± 4.02 and 8.75 ± 3.90, respectively). The highest scores were observed in SE_PFS_Kuraray group (13.46 ± 5.83). Significant differences in SBS and ARI assessments were found. All experimental groups showed type 1 etching pattern. CONCLUSION: The etching pattern was less pronounced in self-etching groups, which showed an equal or superior in vitro performance compared to conventional etching agents. The clinical use of self-etching agents could be recommended before pit and fissure sealants application in new dental protocols. The best in vitro performance was observed when both applied materials, self-etching agent and pit and fissure sealant have 10-methacryloyloxydecyl dihydrogen phosphate in their chemical composition.

Morphological, chemical and structural characterisation of deciduous enamel: SEM, EDS, XRD, FTIR and XPS analysis.

AIM: The purpose of this study was to characterise the enamel surface of sound deciduous teeth in terms of morphology, chemical composition, structure and crystalline phases. MATERIALS AND METHODS: The enamel of 30 human deciduous teeth was examined by: Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), X-ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS). Chemical differences between incisors and canines were statistically evaluated using the Mann-Whitney U test (p ≤ 0.05). RESULTS: Three enamel patterns were observed by SEM: 'mostly smooth with some groves', 'abundant microporosities' and 'exposed prisms'. The average Ca/P molar ratios were 1.37 and 1.03 by EDS and XPS, respectively. The crystallite size determined by XRD was 210.82 ± 16.78 Å. The mean ratio between Ca bonded to phosphate and Ca bonded to hydroxyl was approximately 10:1. CONCLUSION: The enamel of sound deciduous teeth showed two main patterns: 'mostly smooth with some groves' and 'abundant microporosities'. 'Exposed prisms' was a secondary pattern. There were slight variations among the Ca/P molar ratios found by EDS and XPS, suggesting differences in the mineral content from the enamel surface to the interior. The crystalline phases found in enamel were hydroxyapatite and carbonate apatite, with major type B than type A carbonate incorporation.

Adhesion of Streptococci to various orthodontic composite resins.

BACKGROUND: This investigation aimed to determine quantitatively the adhesion of Streptococcus mutans and Streptococcus sobrinus to orthodontic composite resins that were tested simultaneously using radio-markers. METHODS: Seven orthodontic composite resins were classified into seven groups: BeautyOrtho Bond (GI), Blugloo (GII), Enlight (GIII), Grengloo (GIV), Kurasper F (GV), Transbond CC (GVI) and Turbo Bond II (GVII). Thirty 4 x 4 x 1 mm blocks of each orthodontic composite resin were made (a total of 210 blocks). Both Streptococcus species were cultivated independently. For the quantitative analysis, radioactive markers were used to codify the bacteria ((3) H for Streptococcus mutans and (14) C for Streptococcus sobrinus). The blocks were submerged in a solution with microorganisms previously radiolabelled for 2 hours at 37 °C in constant movement. The blocks were placed in a combustion system to quantify the Streptococcus adhering to the surface of the materials by capturing the residues and measuring the radiation. RESULTS: Significant differences in bacterial adhesion were found among the groups. The lowest significant scores for both microorganisms were observed in GIII. CONCLUSIONS: The orthodontic composite resin evaluated in GIII exhibited the lowest adhesion of Streptococcus mutans and Streptococcus sobrinus, which may reduce enamel demineralization and the risk of white spot lesion formation.

Adherence of Streptococcus mutans to orthodontic band cements.

BACKGROUND: The aim of this study was to quantitatively determine the adherence of Streptococcus mutans to orthodontic band cements. METHODS: Two hundred and ten blocks of seven different band cements for orthodontic prescription were made using a Teflon mould (4 × 4 × 1 mm). The obtained blocks were slightly polished and cleansed ultrasonically. Certified S. mutans ATCC 25175 were cultured with conventional methods for growth in Petri dishes and trypticase soy broth. Quantitative analysis was carried out with radioactive markers to codify the bacteria ((3) H). Subsequently, a combustion system was used to capture the residues, the radioactivity of the samples was measured, and the values recorded in disintegrations per minute (dpm). One-way analysis of variance (ANOVA) with a Scheffé test for multiple comparisons was realized with a significance level of ≤0.05. RESULTS: Significant differences were found among different band cement materials (p < 0.001). Two band cement materials showed statistically lower values than the others (Transbond Plus Band Cem and Ketac Cem). In contrast, GC Fuji Ortho Band presented the highest adherence of S. mutans. CONCLUSIONS: Among the cements evaluated, Transbond Plus Band Cem and Ketac Cem showed lower adherence of S. mutans.

Dental caries and treatment needs in street children in Toluca, Mexico.

OBJECTIVE: To assess dental caries (deft and DMFT) and treatment needs, in street children from the city of Toluca in Mexico. METHODS: After informed consent from their parents, guardian or legal representative, 310 street children, 0 to 17 years of age, from Toluca in the state of Mexico, were evaluated. Caries and treatment needs were recorded according to 1997 WHO criteria. The oral examination was carried out on site in daylight. RESULTS: For the population from which the sample was derived, the caries prevalence was 94.96%, the mean DMFT was 6.0 +/- 4.6 (5.8 decayed), while deft was 3.5 +/- 3.7 (3.4 decayed). Treatment needs in the deciduous dentition revealed that 43.9% of teeth did not require any treatment, 20% needed fissure sealants, 19% required one surface restoration and 13.19% needed restoration in two or more surfaces. In the permanent dentition, the treatment needs were as follows: 51.2% teeth did not need any treatment, 22.9% needed fissure sealants, 18.4% required one surface restoration and 5.3% needed restoration in two or more surfaces. CONCLUSIONS: These findings illustrate the high prevalence of caries in street children in the city of Toluca. There is an enormous need for dental treatment; sealant applications were the treatment most in need. The data can serve as a platform to implement preventive and restorative dental health programmes that meet the needs of Mexican street children,

Co-factors related to the causal relationship between human papillomavirus and invasive cervical cancer in Honduras.

BACKGROUND: A case-control study was conducted in Honduras to identify co-factors in the carcinogenic pathway by which human papillomavirus (HPV) causes invasive cervical cancer. METHODS: Ninety-nine cases aged 23-65 (median 47) years participated. Two controls were matched to each case by age and clinic where they first presented for cytological screening; controls had no cervical abnormalities. Information on risk factors was obtained by personal interviews in the clinics regarding sociodemographic, reproductive and behavioral characteristics. Human papillomavirus was detected in cervical scrapes by general primer-mediated polymerase chain reaction (PCR) followed by sequence analysis to identify the different types present. RESULTS: All cases had squamous cell tumours and most were FIGO (International Federation of Gynecologists and Obstetricians) class II or higher; HPV was strongly associated with cervical cancer (odds ratio [OR] = 7.66, 95% CI : 3.88-15.1). Among HPV-positive women, dose-response relationships were observed for education, age at first intercourse and exposure to wood smoke that persisted after adjustment for previous screening. Among HPV-negative women, the number of sexual partners and parity were associated with cervical cancer. The protective effect of previous cytological screening operated independently of HPV. CONCLUSIONS: Our findings speak for the powerful role that both primary and secondary education plays in fostering a lifestyle that reduces the risk of invasive cervical cancer. The data suggest that important elements of such a lifestyle include later age at first sexual intercourse, a limited number of pregnancies, greater likelihood of undergoing cytological screening and reduced exposure to carcinogens in the household environment.

Human papillomavirus infection, cervical dysplasia and invasive cervical cancer in Honduras: a case-control study.

A substantial body of evidence has confirmed human papillomavirus (HPV) infection as the central etiological agent in human cervical carcinogenesis. In Honduras, cervical cancer is the most common cancer among women, with a high annual incidence. We conducted a population-based, case-control study of 229 patients with different grades of CIN and invasive cervical cancer and 438 matched controls. A structured questionnaire was used to investigate known and probable risk factors for cervical cancer. Cervical scrapes were tested for the presence of different HPV types using a general primer-mediated PCR followed by PCR-based sequencing. HPV DNA was detected in 87% of all cancer in situ and invasive cancer cases, and 95% of invasive cases could be attributed to high-risk types. In control women, 39% were positive for HPV DNA sequences. HPV 16 prevalence ranked highest in all stages of cervical dysplasias, invasive cancers and controls. A statistically significant association with HPV was observed for CIN II, CIN III and invasive cancer, showing an upward trend to more severe lesions and being more pronounced for HPV 16 and related types. The OR for HPV 16- and 18-related invasive cancer cases was 14.88 (95% CI 5.12-43.25) and 74.66 (95% CI 7.77-717.62), respectively. Our results confirm a central role of HPV as the cause of cervical cancer in Honduras and provide information as to the type distribution of HPVs in the country.

Infección por virus de inmunodeficiencia humana en mujeres: experiencia de un hospital de enfermedades infecciosas en Chile: 1988-1994 / Human immunodeficiency virus infection in women: experience of an infectious disease hospital in Chile: 1988-1994

Se revisaron retrospectivamente las fichas clínicas de 26 mujeres con infección por VIH atendidas en el Hospital Dr. Lucio Córdova L. entre enero de 1988 y diciembre de 1994. El 79,6 por ciento de las pacientes tenía entre 20 y 39 años. La infección fue adquirida en forma sexual en 73,1 por ciento, por transfusiones sanguíneas en 15,4 por ciento, ambos antecedentes estaban presentes en 7,7 por ciento y el mecanismo fue desconocido en 3,8 por ciento. El principal factor de riesgo fue el contacto sexual con pareja portadora del VIH (69,2 por ciento). La patología definitoria de SIDA más frecuente fue la neumonitis intersticial por P. carinii confirmada o presunta. La candidiasis orofaríngea y las manifestaciones herpéticas oro-genitales fueron las patologías más prevalentes. Dos pacientes (7,7 por ciento) tuvieron Ca. cérvico-uterino. Ocho enfermas (30,7 por ciento) fallecieron, 5 por complicaciones neurológica

Bacteremia por streptococcus beta hemoliticus grupo A / Streptococcus beta hemoliticus group A bacteremia

Se estudian 22 pacientes con bacteremia por Streptococcus beta hemolítico grupo A, tratados en el Hospital Lucio Córdova entre 1990 y 1995. Observamos un incremento epidémico en la última década, tanto en el número de pacientes admitidos en el hospital, como en la agresividad de la infección. En más de la mitad de los casos (54,5 por ciento) la puerta de entrada fue cutánea, encontrándose signología inflamatoria inespecífica (eritema, edema, aumento de temperatura, dolor y/o herida localizada) en la totalidad de éstos; y, sólo en la mitad, elementos sugerentes de infección estreptocócica, tales como bulas, ampollas y/o celulitis necrotizante. La complicación principal, tanto por su frecuencia, como por su gravedad, fue el Síndrome de Shock Tóxico, que apareció en 7 casos (31,8 por ciento). Todos los pacientes que presentaron dicho síndrome, fallecieron; 6 de ellos dentro de las primeras 48 horas de ingreso al hospital. Tuvimos una letalidad de 36,3 por ciento