Antibiotic prescribing in dental practice in Belgium.

AIM: To assess the types and frequency of antibiotic prescriptions by Belgian dentists, the indications for antibiotic prescription, and dentists' knowledge about recommended practice in antibiotic use. METHODOLOGY: In this cross-sectional survey, dental practitioners were asked to record information about all antibiotics prescribed to their patients during a 2-week period. The dental practitioners were also asked to complete a self-administered questionnaire regarding demographic data, prescribing practices, and knowledge about antibiotic use. A random sample of 268 Belgian dentists participated in the survey. RESULTS: During the 2-week period, 24 421 patient encounters were recorded; 1033 patients were prescribed an antibiotic (4.2%). The median number of prescriptions per dentist for the 2 weeks was 3. Broad spectrum antibiotics were most commonly prescribed: 82% of all prescriptions were for amoxycillin, amoxycillin-clavulanic acid and clindamycin. Antibiotics were often prescribed in the absence of fever (92.2%) and without any local treatment (54.2%). The most frequent diagnosis for which antibiotics were prescribed was periapical abscess (51.9%). Antibiotics were prescribed to 63.3% of patients with periapical abscess and 4.3% of patients with pulpitis. Patterns of prescriptions were confirmed by the data from the self-reported practice. CONCLUSIONS: Discrepancies between observed and recommended practice support the need for educational initiatives to promote rational use of antibiotics in dentistry in Belgium.

Orthodontic loading of titanium miniplates in dogs: microradiographic and histological evaluation.

OBJECTIVES: The objectives of this animal study were to evaluate if orthodontic loading has an impact on osseointegration of screws supporting miniplates, and to describe the histological components of the bone-screw interface. MATERIALS AND METHODS: Eighty orthodontic miniplates were placed in the jaws of 10 dogs. After 2 weeks, a 125 g force was applied between the miniplates of one upper quadrant of each dog and between those of the controlateral lower quadrant. The others, nonloaded miniplates, were considered as controls. Five dogs were sacrificed 7 weeks after implantation and the remaining five dogs after 29 weeks [Short Term (ST) and Long Term (LT) groups, respectively]. Fluorochromes were injected at implantation and at sacrifice. Jaw quadrants were dissected, embedded, cut into undecalcified transverse sections through the screws and finally submitted to microradiographic analysis to allow assessment of bone-implant contact (BIC) and bone volume/total volume (BV/TV). The sections were observed under UV light and stained in order to examine them under ordinary light. RESULTS: Osseointegration occurred around 90/160 screws and consisted mainly in limited repair and remodelling processes of lamellar bone, without inflammation. Wide variations were observed in BIC and BV/TV, but without any significant difference, neither between the loaded and the nonloaded screws, nor according to the direction of load, whereas they were significantly higher in the LT than in the ST group. Nonosseointegrated screws were surrounded by fibrous tissue. Osteoblastic activity, when present in front of these screws, was not sufficient to achieve stability. CONCLUSIONS: Osseointegration underlying orthodontic anchorage was not affected by loading. BIC increased with time and varied according to implantation site. Particularly the tight-fitting screw insertion appeared crucial in determining the appropriate bone healing response.

Malaria control among children under five in sub-Saharan Africa: the role of empowerment and parents' participation besides the clinical strategies.

CONTEXT: Child malaria remains a vital concern in sub-Saharan Africa in spite of major efforts to control it. The widely advertised best curative and preventive measures are not always accessible. ISSUE: This article examines the extent to which parents' perceptions and representations are considered, including their empowerment and participation in interventions aimed at controlling child malaria. The effect of this is examined through a content analysis of articles selected in the PubMed and Wholis databases over the period of 1996 to 2005. This analysis was performed according to three predefined categories consistent with the three main health promotion strategies used in the WHO-AFRO region: (1) development of knowledge and skills; (2) creation of supportive environments; and (3) advocacy. LESSONS LEARNED: Successful interventions met the health promotion strategies wholly or partly. Although these interventions were sometimes incomplete, the development took into account people's perceptions and representations. The authors acted on the belief that empowerment of parents and their participation in the development of interventions to control child malaria, is likely to yield better results and assist in reducing the prevalence of malaria morbidity and mortality in children under 5 years.

Effects of irradiation on bone remodelling around mandibular implants: an experimental study in dogs.

This research focuses on the effects of radiotherapy on bone remodelling around mandibular implants in dogs. After bilateral extraction of the mandibular premolars and first 2 molars, each of 11 beagles received 8 mandibular implants. Four animals were irradiated 4 weeks after implantation and 4 others 8 weeks before implantation; the remaining 3 did not receive radiotherapy. Irradiation consisted of 10 daily fractions of 4.3Gy (60)Co. Fluorochromes were given at implantation and irradiation to allow the measurement of bone apposition. The dogs were killed 6 months after implantation. Each hemi-mandible was processed according to bone-specific histological techniques. New bone formation was visible around 85 of the 88 implants. Stimulated mandibular remodelling was attested in both irradiated groups by increased porosity and numerous labelled osteons. Resorption was more pronounced in the group irradiated after implantation, but osteon formation appeared unvarying. Osseointegration was thus shown to be compatible with bone irradiation as bone turnover activities were maintained throughout the experiment. As the apposition stage of the remodelling cycle appears crucial to achieve optimal osseointegration, its normal completion should be taken into account in clinical practice by respecting a 6-month period between irradiation and implantation.

Nurses' health, age and the wish to leave the profession--findings from the European NEXT-Study.

BACKGROUND AND OBJECTIVES: In many industrialised countries the number of workers with low health is expected to increase in the nursing profession. This will have implications for occupational health work in health care. The European NEXT-Study (www. next-study. net, funded by EU) investigates working conditions of nurses in ten European countries and provides the opportunity to evaluate the role of health with respect to age and the consideration of leaving nursing. METHODS: 26,263 female registered nurses from Belgium, Germany, Finland, France, England, Italy, Netherlands, Poland and Slovakia were eligible for analysis. RESULTS: In most countries, older nurses considered leaving the profession more frequently than younger nurses. 'Health' was--next to 'professional opportunities' and 'work organisational factors'--strongly associated with the consideration of leaving nursing. However, more than half of all nurses with low health wanted to remain in the profession. This group reported rather positive psychosocial working conditions--but also the highest fear for unemployment. CONCLUSIONS: The findings indicate that 'the nurse with low health' is reality in many health care settings. Both positive supporting working conditions but also lack of occupational alternatives and fear of unemployment may contribute to this. Current economic, political and demographic trends implicate that the number of active nurses with low health will increase. Occupational health surveillance will be challenged by this. But NEXT findings implicate that prevention also will have to regard work organisational factors if the aim is to sustain nurses' health and to enable nurses to remain healthy in their profession until retirement age.

Practical considerations on the use of the Charlson comorbidity index with administrative data bases.

To develop a measure of the burden of comorbid disease from the MED-ECHO data base (Québec), the so-called Charlson index was adapted to International Classification of Disease (ICD-9) codes. The resulting comorbidity index was applied to the study of inpatient death in 33,940 patients with ischemic heart disease. Multiple logistic regression was used to relate inpatient death to its predictors, including gender, principal diagnosis, age, and the comorbidity index. Various transformations of the comorbidity score were performed, and their effect on the predictive accuracy was assessed. The comorbidity index was constantly and strongly associated with death. From a statistical viewpoint, the best results were obtained when the index was transformed into four dummy independent variables (the area under the receiver-operating curve is then 0.87). In a validation analysis performed on 1990-1991 MED-ECHO data (36,012 admissions with ischemic heart disease), the comorbidity index has the same statistical properties. We conclude that the Charlson index may be an efficient approach to risk adjustment from administrative data bases, although it should be tested on other conditions.

Evaluation of chlorhexidine and silver-sulfadiazine impregnated central venous catheters for the prevention of bloodstream infection in leukaemic patients: a randomized controlled trial.

It has been suggested that central venous catheters impregnated with antiseptics such as chlohexidine and silver-sulfadiazine reduce the risk of catheter-related bacteraemia in intensive care patients. Patients suffering from haematologic malignancy treated by chemotherapy through a central venous catheter are at even greater risk of catheter-related bacteraemia. A prospective double-blind randomized controlled trial was performed in order to investigate the effectiveness of chlorhexidine and silver-sulfadiazine impregnated catheters (CH-SS) in these patients. A total of 680 catheters (13,826 catheter days) were inserted, of which 338 were antiseptic impregnated. Bloodstream infection was observed in 105 cases with an overall risk of 7.6 per 1000 catheter days. Thirty-two infections (30.5%) were catheter-related, corresponding to a risk of 2.3 per 1000 catheter days. There was no statistically significant different between the overall rates of bloodstream infection for impregnated and non-impregnated catheters (14.5 vs. 16.3%). The incidence of catheter-related infection was also similar in both groups (5 vs. 4.4%) and there was no difference in the time of the onset of bacteraemia in the two groups. It is concluded that the use of CH-SS catheters in patients with haematologic malignancy reduces neither the overall risk of bloodstream infection, nor the catheter-related infection rate, nor the delay for the occurrence of infection.

Meta-analytical review of factors involved in dentin adherence.

Literature data on adherence tests of dentin-bonding systems (DBS) may differ widely, even for the same DBS. The problem of bond testing is that materials are seldom compared with a standard, and experimental conditions often vary. We sought to identify the parameters that influence this variability. Using inclusion and exclusion criteria, we conducted a meta-analytical review of 75 articles, published between 1992 and 1996 in SCI reviews, that give bond strength data for 15 dentin-bonding agents of the so-called third and fourth generations. Seventeen selected parameters were classified into four groups: Group A includes factors related to the dentin substrate (i.e., nature of teeth); group B, composite and bonding area (i.e., composite stiffness); group C, storage conditions of the bonded samples (i.e., thermocycling); and group D, test design (i.e., crosshead speed). For each report, the experimental features, the bond strength means and standard deviations, and the failure mode were extracted and tabulated. Statistical Analysis System software was used to perform Pearson correlation analysis and analysis of variance, with bond strength as the dependent variable and experimental conditions as the independent variables. The meta-analytical review highlighted the significant influence of various parameters in the different groups: origin of dentin, types of teeth, pulpal pressure, tooth storage temperature, maximum storage time of teeth, and dentin depth in group A; type and stiffness of composite and bonding area in group B; storage of bonded samples (medium, temperature, and time) in group C, and testing mode and crosshead speed in group D. A significant positive correlation was observed between the mean bond strength and the rate of cohesive failure. It can be concluded from this study that some of these parameters should be controlled by the use of a standardized protocol. Unfortunately, the substrate-related variables are more difficult to control, even though their influence is consistent.

The opinion of general practitioners on the treatment of prostate and breast cancer in elderly people: results of a survey based on clinical models.

AIMS: Several publications have reported age-related differences in the management of people with cancer. Most data have been derived retrospectively from hospital or cancer-centre databases. The aim of the present study was to identify major decisional factors observed in general practitioner (GP) practices, outside the hospital setting, regarding the clinical management of patients with prostate and breast cancer. MATERIALS AND METHODS: During three national GP meetings in Belgium, questionnaires presenting two simulated patient cases were presented to GPs who were asked two questions: one regarding further staging and referral of the case and the second regarding the treatment of the case. A total of 678 questionnaires were distributed. GPs received two randomly selected cases each: a breast cancer history and a prostate cancer history. Three variables were assessed simultaneously: age, performance status and medical history (comorbidity). RESULTS: The analysis indicated that elderly patients were more likely to be referred for non-curative treatment (OR 13.71; 95% CI 5.67-33.12; P < 0.0001 for prostate cancer and OR 17.67; 95% CI 4.04-77.31; P < 0.0001 for breast cancer). The other variables (performance status and medical history) did not affect treatment orientation. However, GPs were prepared to seek assistance from oncologists in both cases, irrespective of the patient's age. CONCLUSION: Age seems to be more important among GPs in deciding how to manage cancer patients than performance status and comorbidity. This is a very common prejudice. They are, nevertheless, inclined to refer people with cancer to oncologists independently of the patient's age.

Implants placed in an irradiated dog mandible: a morphometric analysis.

The objective of this research was to evaluate the influence of radiotherapy on the osseointegration of oral implants in a canine model. After the extraction of all mandibular premolars and first and second molars, 11 male beagles were divided into 3 groups. The control group (3 dogs) received no radiation. The second group (4 dogs) was irradiated 4 weeks after implantation. The third group (4 dogs) was irradiated 8 weeks before implantation. Eight implants were placed in each dog, in an alternating pattern: 4 non-submerged ITI Bonefit titanium plasma spray-coated and 4 submerged Steri-Oss hydroxyapatite-coated. The irradiated dogs received 4.3 Gy daily for 10 days. After 6 months of osseointegration, the dogs were sacrificed and each hemimandible was dissected to isolate the implants. Quantification of the extent of the direct bone-implant contact was carried out by scanning electron microscopy backscattered electron images that reproduced each implant in its entirety, using a digitizing table connected to a computer. The results were expressed as a percentage of direct bone-implant contact versus total perimeter accessible to bone. The bone contact percentage for the control group was 87% for Steri-Oss implants and 69% for the ITI Bonefit implants; for the animals irradiated after implantation, the percentages were 82 for Steri-Oss implants and 58 for ITI Bonefit implants; and for the animals irradiated before implantation, the percentages were 62 for Steri-Oss implants and 28 for ITI Bonefit implants. A statistically significant difference appeared between the 2 types of implants (P < .001). A statistically significant difference was also seen between the 3 groups for both types of implants, except between the control group and the group irradiated after implantation (P = .14). This indicates that, overall, the timing of irradiation influences osseointegration. Osseointegration is possible before and after radiotherapy; however, the direct bone-implant contact increased when the implants were placed before irradiation.

Risk adjustment in outcome assessment: the Charlson comorbidity index.

To measure the burden of comorbid diseases using the MED-ECHO database (Quebec), the so-called Charlson index was adapted to International Classification of Disease (ICD-9) codes. The resulting comorbidity index was applied to the study of inpatient death in a group of 62,456 patients having one of the following conditions: ischemic heart disease, congestive heart failure, stroke, or bacterial pneumonia. Multiple logistic regression was used to relate inpatient death to its predictors, including gender, principal diagnosis, age, and the comorbidity index. Various transformations of the comorbidity score were performed, and their effect on predictive accuracy was assessed. The comorbidity index was constantly and strongly associated with death. When gender, age, comorbidity and the principal diagnoses were taken into account, the area under the receiver-operating curve was 0.83. Therefore, the Charlson Index is a useful approach to risk adjustment in outcomes research from administrative databases.

The decline in dental caries among Belgian children between 1983 and 1998.

OBJECTIVES: to investigate cross-sectionally a probable dental caries decline in Belgian 12-yr-olds and to analyse some factors that may be associated with dental caries during the study period. METHODS: In the region of Brussels, children in the 7th grade at the same schools were sampled in 1983 (n=533) and 1998 (n= 496). DMFT, DMFS and dental fluorosis were clinically recorded. Data on children's home-based and professional dental health care habits were registered. RESULTS: Caries-free children increased from 4% to 50%. A reduction of the mean number of teeth attacked by dental caries from 7.5 to 1.6 and of tooth surfaces from 11.5 to 2.5 (P<0.001) was observed. Early signs of dental fluorosis were identified in 5% in 1983 and 30% of the subjects in 1998. Multiple linear regression analyses revealed that tooth brushing with fluoridated toothpaste, dental appointments and dental fluorosis were significantly related to dental caries reduction. CONCLUSIONS: A remarkable decline in dental caries was observed during the 15-yr period. The factors related to the children's home-based and professional dental health care were associated with the observed decline.

Caries decline in the primary dentition of Belgian children over 15 years.

OBJECTIVES: (1) To investigate changes in caries prevalence in the primary dentition of children resident in Brussels, Belgium between 1983 and 1998, (2) to analyse associations between changes in caries and children's socioeconomic and ethnic aspects. METHODS: In the Brussels region, children in the first grade at the same schools were sampled in cohort 1983 (n = 396) and cohort 1998 (n = 473). Caries experience of Belgian and non-Belgian nationals was summarized in dmf scores. The socioeconomic status of the children was established based on their parents' education and profession. The children were categorized in eight subgroups in relation to their socioeconomic status, ethnic origin and cohort (SESEC subgroups). RESULTS: The percentage of caries-free children increased significantly from 31.5% to 47.5%. A reduction was observed in the dmft scores from 3.9 to 2.3 (P < 0.001) and in the dmfs scores from 6.9 to 5.0 (P < 0.001). The odds ratio of being caries-free was 2.5 times higher for privileged children and 2.3 times higher for children belonging to cohort 1998. The ANCOVA analyses revealed that most of the SESEC subgroups showed significant reduction in dmft scores from 1983 to 1998 (P < 0.003). CONCLUSIONS: Children resident in Brussels showed caries decline in their primary dentition over 15 years. Diversity in caries decline was associated with children's socioeconomic status and ethnic origin.

Long-term evaluation of extensive restorations in permanent teeth.

OBJECTIVES: The present prospective, longitudinal study assessed the outcome of posterior extensive restorations and identified risk factors for failure of the restorations. MATERIALS AND METHODS: The sample consisted of 722 amalgam restorations, 115 composite resin restorations and 89 crowns placed in 428 adults by one dentist from 1982 to 1999 in Belgium. Well-defined criteria were used for cavity preparation design, type of retention and selection of restorative material. RESULTS: At the closure of the study 48% of the restorations were well functioning, 24% were lost to lack of follow-up, and 28% had failed. The most frequent reasons for failure were fracture of restoration (8%), secondary caries (6%) and fracture of cusp (5%). Failures were more often found in premolar teeth (34%) than in molars (27%) (P=0.05) and occurred in 28% of the amalgam restorations, 30% of the resin restorations and 24% of the crowns (P=0.55). Molar restorations were more frequently repaired than replaced in contrast to premolar restorations. The highest percentage of extractions was related to complete amalgam restorations in premolars. The Kaplan-Meier median survival times were 12.8 years for amalgam restorations, 7.8 years for resin restorations, and more than 14.6 years for crowns, considering all retreatment as failures (P=0.002). The survival was influenced by extension of restoration, age of patient, pulpal vitality, 3-year period of treatment, use of base material and dentinal retentive pins. CONCLUSION: Within the limits of the study the data support the view that extensive amalgam restorations but not composite resin restorations can be used as an appropriate alternative to crowns, with due consideration to the longevity of the restorations.

The importance of repeated risk assessment for pressure sores in cardiovascular surgery.

BACKGROUND: Patients undergoing cardiovascular surgery are at high risk for sores because of impaired perfusion, the time spent on the operating room table, and restricted mobility in the immediate postoperative period. OBJECTIVE: To identify risk factors for sores. METHODS: In a 900-bed teaching hospital, 163 patients who underwent cardiovascular interventions were enrolled. Risk measurement included skin assessment, Braden and Norton scales, physic and biologic data and specific risk factors. The development of the most severe stages of pressure sores was followed (Stages II and III). RESULTS: Forty-eight (29.5%) patients totalized 75 pressure sores. In univariate analyses, Norton and Braden scores, hemoglobin concentration, presence of ulcers at admission, use of antihypertensive drugs, systemic use of corticosteroids, nosocomial infection, re-intervention and readmission in intensive care units were associated with sores. In a logistic regression model, hemoglobin concentration at admission (p=0.0007), postoperative Braden score (p=0.0002), and postoperative steroid therapy (p=0.020) were the only predictors of sores. Total length of stay was 6 days higher (p=0.03) for patients with pressure sores. CONCLUSIONS: The detection of risks is recommended during the entire stay. Identification of patients at risk is required to provide preventive resources appropriately, which can lessen the incidence of pressure sores and reduce patient discomfort, length and costs of hospital stay.

Reliability of in vitro microleakage tests: a literature review.

PURPOSE: The literature contains conflicting data about in vitro microleakage evaluations and their usefulness and reliability. No standardization has yet been established. Here we consider features of published studies that might affect the results of the in vitro microleakage tests. MATERIALS AND METHODS: We reviewed 144 in vitro microleakage studies, published in 14 international reviews between 1992 and 1998, which comprised 917 sets or groups of experiments. The published studies were entered in a database and compared using selected literature criteria: sample, cavities, restoration procedures, thermocycling and mechanical cycling, evaluation method. RESULTS: The methods employed vary widely. The most frequent methodological choices (%) were (1) specimen storage after extraction: duration (unspecified, 59.2), medium (distilled or deionized water, 33.8), temperature (unspecified, 52.2), additives (none, 47.0); (2) aging method (79.1): duration before aging (< 24 h, 35.9); medium and temperature of storage before aging (distilled or deionized water, 26.8; 37 degrees C, 54.3); (3) medium of cycling (tap water, 50.5), number of cycles ([250-500], 34.6), number of baths (2, 84.0), bath temperature (5 degrees C to 55 degrees C, 60.6), immersion dwell time (30 s, 44.3); (4) tracer: type (basic fuchsin, 40.7), time of immersion (after thermocycling and/or mechanical cycles, 64.1), immersion duration (basic fuchsin: 24 h, 59.5); assessment of dye penetration of sections (91.7): direction (perpendicular, 88.5), number (1, 47.1). CONCLUSION: The great variability in the methods used in these 144 studies prevented meta-analysis and comparison of the results, thus reducing the value of these methods.

Using the handicap code of the ICIDH for classifying patients by intensity of nursing care requirements.

An 11-class patient classification system (PCS) has been built on a recode of two dimensions of the handicap code of the ICIDH: physical independence and mobility handicaps. The proposed system, called MAC XI, explains 78% of the variance of nursing care hours required by nursing-home residents and extended-care hospital patients. This percentage of variation is higher than the one explained by traditional dependency grids such as the Exton-Smith, Murphy, Kuntzmann and SMAF. MAC XI, based on two dimensions of the handicap code, is thus a powerful tool for predicting intensity of nursing care for staffing and budgeting purposes in long-term care institutions.

Two-level non-invasive positive pressure ventilation in the initial treatment of acute respiratory failure in an emergency department.

There are few data on the use of two-level non-invasive positive pressure ventilation (two-level nIPPV) in the initial treatment of severe acute respiratory failure in emergency departments (ED). In a prospective, non-randomized, pilot study, we assessed (1) the feasability of this method in an ED, (2) its effect on clinical and laboratory data, and (3) its effect on the need of intubation and the final outcome of patients. During a 1-year period all eligible patients admitted for acute respiratory failure, with absence of improvement after periods of specific classic treatments, were included in the study. Each patient received a specific classic treatment and two-level nIPPV with a two-level positive pressure ventilator through a face mask. We recorded parameters on admission, after 15 and 45 minutes of nIPPV and at the end of nIPPV. Sixty-two patients were included: 29 with acute pulmonary oedema (APO), 16 with acute exacerbation of chronic obstructive pulmonary disease (COPD), four with asthma, and 13 with various diseases. In the APO-group, we observed a statistically significant improvement of respiratory and pulse rates, diastolic blood pressure, pH, PaCO2 and SaO2. In acute exacerbation of COPD, we observed only a statistical improvement of respiratory and pulse rates without any significant change of PaCO2 and pH. In the two other groups, there was a clinical, gasometric and haemodynamic improvement in all patients. Four patients were intubated and 10 died, but none in the ED or in the first 24 hours after hospital admission. We were able to institute two-level nIPPV for severe acute respiratory failure in an ED without complications. Its addition to the rest of classic specific treatment seems to bring about a rapid improvement of various clinical and laboratory parameters in most patients. We found no deleterious effect of nIPPV when implemented for short periods of time in the emergency department setting.

[Application of the tracer method in the evaluation of the quality of dental care in 3237 Belgian schoolchildren]. / Application de la méthode des traceurs à l'évaluation de la qualité des soins dentaires chez 3237 écoliers belges.

In this paper, we describe the social distribution of levels of quality of the care to dental caries in 3237 Belgian schoolchildren aged 5 to 21. First, one decayed surface in 4 is filled. The index of filled surfaces of privileged children and of those who regularly consult the dentist is 50% higher than in disadvantaged children and in those who consult for cure. Secondly, one filled surface in 3 is threatened. The index of recurrent caries of privileged children is 30% lower than the one of disadvantaged children. A similar difference is observed between the groups defined by their use of dental services. Thirdly, one decayed surface in 25 is missing. The proportion of missing surfaces is not negligible in disadvantaged children and in those who consult the dentist for cure. We conclude that the system of dental care does not favor equity nor maintenance of dental health.

[Analysis of the relations between polysomnographic data and subjective evaluation of sleep in a group of normal subjects]. / Analyse des relations entre les données polysomnographiques et l'évaluation subjective du sommeil dans un groupe de sujets normaux.

The aim of the present study was to analyse the relationships between polysomnographic variables and the subjective evaluation of sleep quality in a sample of healthy subjects. Thirty one healthy subjects (7 women, 24 men) aged 16 to 74 (mean = 33.8; standard-deviation = 15.6) were included in the study. After one accommodation night, sleep was recorded during three consecutive nights in the sleep laboratory. Subjective evaluation of sleep quality was assessed by a questionnaire including quantitative aspects as well as qualitative aspects of sleep. The data of the third night are analysed here. Two factor analyses were performed on the sleep questionnaire. Two factors were extracted; they were named "depth" and "rest". Using a stepwise multiple regression analysis, these two indices of sleep quality were tested for explanation by 24 polygraphic variables. The "depth" factor was revealed positively related to the first awakening latency, and negatively to sleep onset latency, Rapid Eye Movement latency and the number of awakenings. The "rest" factor was shown to be positively related to stage 1 duration and sleep onset latency, and negatively to stage 4 duration and the number of awakenings. Some of these relationships have already been described. Others seem surprising and may seem questionable. These results raise the question of the relations between objective measures of sleep, the polygraphic variables, and the subjective process of perceiving and evaluating sleep.