Analysis of shade, temperature and hydrogen peroxide concentration during dental bleaching: in vitro study with the KTP and diode lasers.

Many dental bleaching techniques are now available, several of them using a laser source. However, the literature on the exact role of coherent light in the biochemical reaction of the whitening process is very discordant. The aims of this in vitro study were: (1) to compare two different laser sources, a KTP laser with a wavelength of 532 nm and a diode laser with a wavelength of 808 nm, during dental bleaching, and (2) to investigate the relationships among changes in gel temperature, tooth shade and hydrogen peroxide (HP) concentration during laser irradiation. Altogether, 116 bovine teeth were bleached using a 30% HP gel, some of them with gel only and others with gel plus one of the two lasers (532 or 808 nm) at two different powers (2 and 4 W). The KTP laser produced a significant shade variation with a minimal temperature increase. The diode laser led to a higher temperature increase with a greater reduction in HP concentration, but the change in shade was only statistically significant with a power of 4 W. At a power of 2 W, the KTP laser caused a greater change in shade than the diode laser. No significant correlations were found among temperature, HP concentration and shade variation. The KTP laser appears to provide better results with less dangerous thermal increases than the diode laser. This might call into question most of the literature affirming that the action of laser bleaching is by increasing the gel temperature and, consequently, the speed of the redox reaction. Further study is required to investigate the correlations between the parameters investigated and efficacy of the bleaching process.

Multimodal-3D imaging based on µMRI and µCT techniques bridges the gap with histology in visualization of the bone regeneration process.

Bone repair/regeneration is usually investigated through X-ray computed microtomography (µCT) supported by histology of extracted samples, to analyse biomaterial structure and new bone formation processes. Magnetic resonance imaging (µMRI) shows a richer tissue contrast than µCT, despite at lower resolution, and could be combined with µCT in the perspective of conducting non-destructive 3D investigations of bone. A pipeline designed to combine µMRI and µCT images of bone samples is here described and applied on samples of extracted human jawbone core following bone graft. We optimized the coregistration procedure between µCT and µMRI images to avoid bias due to the different resolutions and contrasts. Furthermore, we used an Adaptive Multivariate Clustering, grouping homologous voxels in the coregistered images, to visualize different tissue types within a fused 3D metastructure. The tissue grouping matched the 2D histology applied only on 1 slice, thus extending the histology labelling in 3D. Specifically, in all samples, we could separate and map 2 types of regenerated bone, calcified tissue, soft tissues, and/or fat and marrow space. Remarkably, µMRI and µCT alone were not able to separate the 2 types of regenerated bone. Finally, we computed volumes of each tissue in the 3D metastructures, which might be exploited by quantitative simulation. The 3D metastructure obtained through our pipeline represents a first step to bridge the gap between the quality of information obtained from 2D optical microscopy and the 3D mapping of the bone tissue heterogeneity and could allow researchers and clinicians to non-destructively characterize and follow-up bone regeneration.

Bisphosphonate-related osteonecrosis of the jaws: a case series of 25 patients affected by osteoporosis.

Bisphosphonates (BPs) are used to treat metabolic bone diseases, such as osteoporosis. In this study the occurrence of bisphosphonates-related osteonecrosis of the jaws (BRONJ) is reported in 25 patients who received BP therapy for osteoporosis with different drug schedules. From June 2005 to May 2009, 25 patients affected by BRONJ were observed. A history of oral surgery was reported for 18 patients (72%). Of the 22 patients treated by the authors, 20 (91%) recorded healing improvement with a mean follow-up of 16.6 months, with particular regard for those treated with oral surgery and laser applications (10/22, 45%) who were all characterised by complete mucosal healing over time. The risk of developing BRONJ in patients treated with BP for osteoporosis is lower than in cancer patients, but is not negligible. It is advisable for the prescribing physician to recommend a dental check-up prior to treatment, at least for patients who have not been to the dentist in the last 12 months. An early surgical and possible laser-assisted approach for patients who develop BRONJ is recommended.

Fatal amniotic fluid embolism during legally induced abortion, United States, 1972 to 1978.

Amniotic fluid embolism (AFE) has emerged as an important cause of death from legally induced abortion. In the period 1972-1978, 12 probably and three autopsy-confirmed cases of fatal AFE during legally induced abortion were identified in the United States (12% of all deaths from legal abortion). Fourteen deaths from AFE were associated with labor-inducing techniques, and one with hysterotomy. The risk of death appears to be related to gestational age: the death-to-case rate for AFE increases progressively from nil at less than or equal to 12 weeks' gestation to 7.2 deaths per 100,000 abortions at greater than or equal to 21 weeks' gestation. Because treatment is frequently ineffective, prevention of AFE is critical. Performing abortions early in pregnancy and using curettage techniques whenever feasible should reduce the risk of death from this obstetric accident during legally induced abortion.

PIP: Amniotic fluid embolism (AFE) has increased in importance as a cause of maternal death. During 1968-75 454 women died of AFE in the U.S., or 9% of all maternal deaths. AFE has recently been found to be an important cause of abortion-related deaths; since 1972 AFE has accounted for 12% of all deaths related to legally induced abortion; the overall estimated death-to-case rate for AFE is 0.2/100.000 legal abortions. 15 cases of fatal AFE associated with legally induced abortion were reported in 1978-79, according to the Center for Disease Controls; 3 of these cases were confirmed by autopsy. Age ranged from 16 to 35 years; 7 patients were white, 6 blacks, and 2 were Asian. Gestational age went from 14 to 35 weeks. 5 women had preexisting conditions; 14 women underwent instillation of hypertonic solution, hyperosmolar urea, or PGF2alpha; 1 woman underwent hysterotomy. All women were in labor when manifestations of AFE became evident; death usually occurred soon after the appearance of signs. Risk of death from AFE seems to increase progressively with advancing gestational age; risk at 21 weeks gestation is about 24 times higher than from abortion at 13-15 weeks' gestation. During the same period of time no deaths were associated with curettage abortions. Estimated death-to-case rate for instillation was not significantly different than for hysterotomy; the estimated death-to-case rate for black women and minority women was 2 times higher than for white women. Age did not make a difference in relationship to death. AFE is caused by the forcing of amniotic fluid into the maternal vascular system during the period of intense uterine contractions. The amount of amniotic fluid is much larger during the second and third trimester of pregnancy; this probably explains the increased risk of death from AFE afer 12 weeks' gestation. Prevention rather than treatment of AFE is of paramount importance. 2 measures may reduce the risk of abortion-related AFE: 1) abortion before the 12-15 week, and 2) curettage at about 13 weeks' gestation. Curettage, presumably by avoiding labor contractions, lowers the risk of AFE.

Rapid evaluation methods (REM) of health services performance: methodological observations.

The rapid evaluation method (REM) was developed by WHO in order to assess the performance and quality of health care services, identify operational problems, and assist in taking managerial action. It was tested in five developing countries (Botswana, Madagascar, Papua New Guinea, Uganda and Zambia) between 1988 and 1991. REM consists of a set of observation- and survey-based diagnostic activities, carried out mainly in health care facilities. The article describes the various steps of REM, methodological issues such as setting objectives and using an issue-information matrix, preparation of survey instruments, use of computer software (Epi Info), data quality control, fieldwork, and the use of data to produce useful information for decision-makers. REM aims at bringing prompt and relevant information to planners and decision-makers who need it for a specific purpose. In the present examples, REM provided information for preparing a programme proposal for external funding, for establishing baseline data for a situation analysis, and for assessing staff performance after extensive training in order to improve the curriculum.

PIP: The rapid evaluation method (REM) is a health management tool aimed at bringing prompt an relevant information to planners and decision makers. The method was developed by WHO's Family Health Division and was field tested in mother and child health care and family planning facilities in Botswana, Madagascar, Papua New Guinea, Uganda, and Zambia between 1988 and 1991. The purpose of this paper is to acquaint the reader with the basic components of the method and methodological problems that arise. Each of the data collection instruments employed is described: clinic exit interviews, health staff interviews, observation of task performance, community and staff focus group discussions, review of clinical records, checking of facilities and equipment and supplies, and household interviews. REM was developed because of the apparent problems of too much paperwork and insufficient time for useful analysis and fears of the expense of surveys. There was a need for a quick, accurate, and economical method of evaluation of facilities and client satisfaction. Reference is made to other REM approaches and a review of REM methods. A basic requirement is the involvement of national program managers in the control, implementation, and application of the design; outside consultants furnish information on methods, formats, and analytical techniques as a complement to national efforts. THe first action taken is to define the objectives and specify the topics and issues of concern. A core group is assigned responsibility for REM. The action plan involves the objectives, information desired, sources for information, schedule of activities, logistical arrangements, and budget preparation. The level of detail of the information desired is defined by the core group and its objectives. A matrix of information is developed which includes information requested and sources; an example is provided. The results of the 5-county evaluation revealed methodological concern about the identification of issues and pretesting of instruments, data quality control, advance notice and planning of fieldwork, the need for analysts familiar with Epi Info Software, analysis of quantitative data first and training of leaders for focus groups, and the need for basic results in 7-10 days and a draft report in several weeks.

Mortality among young black women using contraceptives.

Data on the risk of death associated with various contraceptive methods are incomplete. Therefore, we analyzed the mortality rates for young, black inner-city women who used one of four methods of contraception--oral contraceptives, depomedroxyprogesterone acetate, intrauterine (contraceptive) devices, and barrier methods. The subjects were 30,580 15- to 44-year-old women who enrolled at a family planning clinic between 1967 and 1972 and who were observed by monitoring death certificates through the end of 1977. Forty percent of the 218 deaths observed were from accidents and violence. Use of this family planning clinic greatly reduced the risk of death from childbearing; only two deaths were associated with pregnancy and childbirth, compared with the 24 deaths expected. Overall, users of the four methods died at similar, low rates. Given that this study involves considerable loss to follow-up, possible acute effects of contraceptives (eg, infections or thrombosis) are more accurately estimated than possible long-term effects (eg, cancer).

The relationship between birth weight, and arm and chest circumference in Egypt.

This paper is concerned with the prediction of birth weight using simple anthropometric indices, namely mid-arm and chest circumferences. Such indices are important tools in the identification of low birth weight infants in areas where scales are not widely available or where they are likely to be not robust enough to withstand rough treatment. This paper reports data from a study in Assiut, Egypt. The aim was to identify which of the two indices was the better predictor or whether measurements on both arm and chest circumference were required. The results show that chest circumference is the better predictor of birth weight, partly perhaps because its measurement is more replicable. Cut-off points for the identification of low birth weight infants are then identified.

Toxic-shock syndrome in menstruating women: association with tampon use and Staphylococcus aureus and clinical features in 52 cases.

To determine the risk factors associated with toxic-shock syndrome (TSS) in menstruating women, we conducted a retrospective telephone study of 52 cases and 52 age-matched and sex-matched controls. Fifty-two cases and 44 controls used tampons (P < 0.02). Moreover, in case-control pairs in which both women used tampons, cases were more likely than controls to use tampons throughout menstruation (42 of 44 vs. 34 of 44, respectively; P < 0.05). There were no significant differences in brand of tampon used, degree of absorbency specified on label, frequency of tampon change, type of contraceptive used, frequency of sexual intercourse, or sexual intercourse during menstruation. Fourteen of 44 cases had one or more definite or probable recurrences during a subsequent menstrual period. In a separate study, Staphylococcus aureus was isolated from 62 of 64 women with TSS and from seven of 71 vaginal cultures obtained from healthy controls (P < 0.001).

Vaginal colonization with Staphylococcus aureus in healthy women: a review of four studies.

Four studies assessed the frequency of vaginal Staphylococcus aureus colonization in healthy women and associated risk factors. An association was found between S. aureus vaginal colonization and colonization at the labia minora and the anterior nares. Significant risk factors associated with an increased risk of vaginal S. aureus in at least one study were a history of genital herpes simplex infection, insertion of tampons without an applicator, and the use of Rely (Procter & Gamble) tampons. The use of systemic antibiotics within 2 weeks of the vaginal culture decreased the risk of recovery of S. aureus. The overall frequency of vaginal S. aureus in the 808 women in the four studies was 9.2%.